IL304246A

IL304246A - Accessories for circular connectors

Info

Publication number: IL304246A
Application number: IL304246A
Authority: IL
Inventors: Lagziel Rafi; Israel Ingber; Eyal Peleg
Original assignee: Israel Aerospace Ind Ltd; Lagziel Rafi; Israel Ingber; Eyal Peleg
Priority date: 2023-07-04
Filing date: 2023-07-04
Publication date: 2025-02-01
Also published as: WO2025008817A1

Description

ACCESSORIES FOR CIRCULAR CONNECTORS TECHNOLOGICAL FIELD The present disclosure relates to circular connectors, in particular to circular connectors that include an electrical arrangement configured for interconnecting between electrical cables via electrical connector elements, for example pin connectors.

BACKGROUND Circular connectors, also known as cylindrical connectors, are a well known arrangement in the art for enabling interconnection of certain types of electrical components, to thereby enable transmission of analog or digital data, electrical signals or electrical power, for example, between multiple cables, between a circuit box and cables, and the like, especially in the avionics applications.

The circular connector types are commonly classified according to their receptacle housing, for example cable plugs, in-line receptacles, box- and panel-mounted receptacles, bulkhead feed-through, blind-mate connectors and PCB mount connectors.

Conventionally, such connectors comprise two generally cylindrical connector parts, in which a first connector part accommodates a male electrical connector part of an electrical arrangement, and the second connector part accommodates a female connector element of the electrical arrangement. For example such an electrical arrangement can be in the form of an 8-pin connector, or crimped removable pins, or PCB pins, or fixed pin contacts.

Such connectors can also come in different sizes, such as to enable different numbers of pins/sockets to be interconnected.

In practice, the same type of electrical arrangement can be provided to a plurality of cylindrical connectors, such that the first connector part is physically compatible with 0293857313-08 more than one second connector part, which can lead to errors occurring in which a first connector part is connected to the wrong second connector part.

Some manufacturers produce a plurality of different connectors, each having a different, integrally formed, alignment arrangement to avoid such errors, but such a solution requires many different connectors to be manufactured, and stocked by the user, which can have logistical and cost implications. In other cases, the pattern of which one of the male or female connector element is provided in the junction box can be inverted for some of the connectors to minimize connection errors, which can have limited utility in avoiding such errors, and which complicates the arrangements at the junction box itself.

GENERAL DESCRIPTION According to a first aspect of the present disclosure, there is provided a coupler for a circular connector, the circular connector comprising a first generally cylindrical connection element having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;the coupler comprising:a first coupler element connectable to the first connection element, the first coupler element comprising a first portion of an engagement arrangement, the first portion comprising a first geometrical configuration; anda second coupler element connectable to the second connection element, the second coupler element comprising a second portion of the engagement 0293857313-08 arrangement, the second portion comprising a second geometrical configuration; andwherein, when the first coupler element and the second coupler element are connected to the first connection element and the second connection element, respectively, the engagement arrangement is configured to permit axial translation of the first and second connection elements along the common connector axis into the connected configuration, conditional on at least the following conditions for engagement being fulfilled:a) the first geometrical configuration is complementary to, matches or corresponds to the second geometrical configuration at least in an axial direction parallel with common connector axis, so as to fit together when brought together in an axial direction along the common connector axis; anb) the first connection element and the second connection element are coaxially aligned along the common connector axis; andc) the first and second portions of the engagement arrangement are in an engaging enabling position, in which they are oriented about the common connector axis at corresponding angular orientations so as to fit together when brought together in an axial direction along the common connector axis.

For example, each of the first and second coupler elements, when connected to the respective first and second connection element, is constrained with respect to the respective connection element in:pr eventing relative movement in an axial direction along the respective central longitudinal axis;andpreventing relative movement in a radial direction from the respective central longitudinal axis.In some examples, each of the first and second coupler elements, when connected to the respective first and second connection element, is constrained with respect to the respective connection element also in preventing relative movement in a circumferential direction about the respective central longitudinal axis; 0293857313-08 Additionally or alternatively for example, the engagement arrangement acts as a limiter preventing the connection elements when connected to the coupler elements from being brought into the connected configuration unless the conditions for engagement are fulfilled.

Additionally or alternatively for example, at least one of the first and second portions of the engagement arrangement comprises at least one projection and at least the other of the first and second portions of the engagement arrangement comprises a corresponding at least one recess; configured to receive the at least one projection;wherein, in use, when the coupler elements are connected to the respective connection elements:- the at least one projection extends in a direction parallel to the common connector axis; and- the at least one recess is configured to receive the at least on projection in the connected configuration.

Additionally or alternatively for example, in at least a first example the first and second coupler elements are configured to be mounted to a cylindrical outer surface of the respective first and second connection elements. For example, each of the first and second coupler elements comprises a hollow annular body comprising a central longitudinal axis. For example, the hollow annular body comprises at least two arc-shaped members and the arc-shaped member are connected in a hinged manner at one end and configured with a snap-fit closure at the other. Alternatively, the hollow annular body comprises at least two arc-shaped members and the two arc-shaped member are configured at both ends with snap-fit closures.

Additionally or alternatively for example, in at least a second example, the first coupler element comprises a first annular plate configured to be mounted to an axial end surface of the first connection element; andwherein the second coupler element comprises a second annular plate configured to be mounted to the second connection element; 0293857313-08 wherein the first annular plate comprises at least one through-bore passing through a thickness of said plate, and the second annular plate is provided with at least one protrusion configured to extend orthogonal to a surface of said second annular plate;wherein, when the conditions for engagement are fulfilled, the first and second annular plates can be brought together, such that the at least one protrusion is configured to be at least partially received in the at least one through-bore.

For example, the at least one protrusion is configured to taper in a direction away from said second annular plate.

Additionally or alternatively for example, the at least one through-bore comprises at least two through-bores located at predetermined relative angular locations about a central axis of said first annular plate, andwherein the at least one protrusion comprises at least two protrusions configured to be located at predetermined relative angular locations about a central axis of said second annular plate configured to correspond with the predetermined relative angular locations of the at least two through-bores.

In at least a third example, the first coupler element comprises at least one non- rotationally symmetric recess extending therein when viewed along an axis of the at least one recess; andwherein the second coupler element comprises at least one protrusion configured to be mounted to the second connection element, the at least one protrusion configured to extend parallel to an axis of the second connection element, wherein the at least one protrusion comprises a non-rotationally symmetric cross-section taken orthogonal to an axis of the protrusion;wherein, when the conditions for engagement are fulfilled, the at least one protrusion can be passed at least partially through the at least one recess.

For example, the at least one protrusion is configured to taper along the axis thereof. 0293857313-08 Additionally or alternatively for example, the at least one non-symmetrical recess comprises at least two non-symmetric recesses configured to be located at predetermined relative angular locations about the first longitudinal central axis of the first connection element, andwherein the at least one protrusion comprises at least two protrusions configured to be located at predetermined relative angular locations about the second longitudinal central axis of the second connection element configured to correspond with the predetermined relative angular locations of the recesses configured to receive the at least two protrusions.

In at least a fourth example, the first coupler element has a hollow cylindrical shape and comprises a central longitudinal axis, and wherein the first geometrical configuration comprises at least one of a longitudinally extending groove or a protrusion; andwherein the second coupler element has a hollow cylindrical shape and comprises a central longitudinal axis, and wherein the second geometrical configuration comprises at least the other of the longitudinally extending groove or the protrusion;wherein, when the conditions for engagement are fulfilled, the first and second coupler elements, when fixed to the respective first and second connection elements, can be brought together, such that the protrusion is configured to be at least partially received in the groove.The fourth example can be of particular use where the number of pins/sockets of the electrical connection arrangement is small. Alternatively, a circular connecter having a relatively large internal diameter and generally used for a large number of pins/sockets can be used with a relatively smaller number of pins/sockets when implementing the third example.

For example, the protrusion comprises a key extending longitudinally along the respective coupler element.

Additionally or alternatively for example, each of the first and second coupler elements further comprises a flange configured to facilitate fixing of the respective first and second coupler element within the respective first or second connection element. 0293857313-08 Additionally or alternatively for example, each of the first and second coupler elements comprises a plurality of protrusions or grooves located at predetermined angular locations about the respective central axis.

Additionally or alternatively for example, at least a portion of the coupler is made from at least one of- a polymer material, optionally a plastics material; and- a metal, optionally any one of steel, aluminium or titanium;- a composite material of other fiber-reinforced material.

Additionally or alternatively for example, the coupler is configured to be retrofitted on a pre-existing circular connector.

Additionally or alternatively for example, the coupler is suitable for use with any one of a MIL-DTL-38999 circular connector, a micro miniature D38999 circular connector or any other suitable mating by turn connector.

According to a second aspect of the presently disclosed subject matter, there is provided a circular connector comprising a first generally cylindrical connection element each having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;wherein the circular connector is operatively connected with a coupler as defined herein. 0293857313-08 According to the second aspect of the presently disclosed subject matter, there is also provided a circular connector comprising a first generally cylindrical connection element each having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;wherein the circular connector is configured to receive the coupler as defined herein according to the first example;wherein the first coupler element is externally affixed with respect to the first connection element, andwherein the second coupler element is externally affixed with respect to the second connection element.

According to the second aspect of the presently disclosed subject matter, there is also provided a circular connector comprising a first generally cylindrical connection element each having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;wherein the circular connector is configured to receive the coupler according defined herein regarding the second example;0293857313-08 wherein the first connection element comprises an annular axial end surface comprising a plurality of bores, the annular axial end surface being configured to receive thereon the first annular plate; andwherein the second connection element is configured to receive the second annular plate.

For example, the plurality of bores comprises a plurality of blind-bores.

Alternatively for example, the plurality of bores comprises a plurality of through- bores.

According to the second aspect of the presently disclosed subject matter, there is also provided a circular connector comprising a first generally cylindrical connection element each having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;wherein the circular connector is configured to receive the coupler as defined herein regarding the third example;wherein the first connection element comprises an axial end surface configured to receive the first coupler element; andwherein the second connection element is configured to receive the second coupler element.

According to the second aspect of the presently disclosed subject matter, there is also provided a circular connector comprising a first generally cylindrical connection element each having a first longitudinal central axis, and a second generally cylindrical 0293857313-08 connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;wherein the circular connector is configured to receive the coupler as defined herein regarding the fourth example;wherein the first connection element comprises a first annular space around one or more electrical connection elements, the first annular space being configured for receiving the first coupler element; andwherein the second connection element comprises a second annular space around one or more electrical connection elements, the second annular space being configured for receiving the second coupler element.For example, the circular connector comprises any one of a MIL-DTL-389circular connector, a micro miniature D38999 circular connector or any other suitable mating by turn connector.According to a third aspect of the presently disclosed subject matter, there is also provided a kit comprising a plurality of couplers, wherein each coupler is as defined herein, wherein the first portion of the engagement arrangement of one of the plurality of couplers is incompatible with the second portion of the engagement arrangement of at least one other coupler of the plurality of couplers.According to the third aspect of the presently disclosed subject matter, there is also provided a kit comprising a plurality of couplers, wherein each coupler is as defined herein, wherein the first geometrical form of the first portion of the engagement arrangement of one of the plurality of couplers is incompatible with the second geometrical form of the second portion of the engagement arrangement of at least one other coupler of the plurality of couplers. 0293857313-08 For example, a colour of the first coupling element of one of the plurality of couplers does not match a colour of the second coupling element of at least one other coupler of the plurality of couplers.According to a third aspect of the presently disclosed subject matter, there is also provided a kit comprising a plurality of circular connectors and a plurality of couplers as defined herein regarding the first example.According to a third aspect of the presently disclosed subject matter, there is also provided a kit comprising a plurality of circular connectors and a plurality of couplers as defined herein regarding the second example;wherein, in use, the first annular plate is mounted to the first connection element such that the at least one through-bore of the annular plate is selectively aligned with a respective at least one bore of the plurality of bores in the respective connection elements; andwherein, in use, the at least one protrusion of the second annular plate is selectively mounted thereon, so as to extend orthogonally therefrom, at angular locations around the second annular plate corresponding to the at least one through-bore.

According to a third aspect of the presently disclosed subject matter, there is also provided a kit comprising a plurality of circular connectors and a plurality of couplers as defined herein regarding the third example;wherein, in use, the first coupler element comprising the non-symmetrical recess is fixed to the first connection element at a rotational orientation selected by the user; andwherein, in use, the at least one non-symmetrical protrusion is selectively fixed to the second connection element at a rotational orientation selected by the user, so as to correspond with the rotational orientation of the at least one recess selected by the user.

According to a third aspect of the presently disclosed subject matter, there is also provided a kit comprising a plurality of circular connectors and a plurality of couplers as defined in defined herein regarding the second example. 0293857313-08 A feature of at least one example of the presently disclosed subject matter is that circular connectors of the same type can be essentially coded using different pairs of matching coupler elements, which can prevent the respective cables from being incorrectly connected to their connections.

Another feature of at least one example of the presently disclosed subject matter is that the pairs of matching coupler elements can be mounted or fixed to a single type of circular connector, which can enable the provision of multiple differently-coded circular connectors while only needing to store or stock a single type of circular connector.

Another feature of at least one example of the presently disclosed subject matter is that a user can selectively apply pairs of matching coupler elements to circular connectors as needed in the field, which enables greater flexibility in providing the desired coding to circular connectors.

Another feature of at least one example of the presently disclosed subject matter is that the coupler elements can be cheap to manufacture, which enables provision of a more economical coding system.

Another feature of at least one example of the presently disclosed subject matter is that the coupler elements can be retrofit to pre-existing circular connectors, which enables easy coding of pre-existing connectors without the need for replacement.

Another feature of at least one example of the presently disclosed subject matter is that there is no need to acquire a variety of connectors that are integrally coded in a different manner one with respect from another at factory, and instead the same basic model of connector can be used for all the connectors in an electric box, and wherein different couplers are used for each connector. This can provide logistic and/or cost advantages over conventional practice, by reducing the variety of connector stock that is required for any given application, and such an effect can be multiplied when considering that the requirement for a variety of elements to which the connectors can be connected to can also be reduced. 0293857313-08 BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the subject matter that is disclosed herein and to exemplify how it can be carried out in practice, examples will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Fig. 1 shows schematically an example of an electrical/avionics junction box arrangement example for use with a plurality of circular connectors that are connected to a plurality of cables . Fig. 2 shows in isometric view an example of a circular connector having first and second connection elements, wherein the circular connector is in a disconnected configuration. Fig. 3 shows in isometric view the example of Fig. 2, in a connected configuration; Fig. 4 shows in isometric view, the circular connector example of Fig. 2 in the disconnected configuration, and including a coupler according to a first example of the presently disclosed subject matter. Fig. 5 shows in isometric view a first coupler element of the coupler example of Fig. 3. Fig. 6 shows in isometric view a second coupler element of the coupler example of Fig. 3. Fig. 7 shows in isometric view a first connection element of a second example of a circular connector, in conjunction with a first coupler element of a coupler according to a second example of the presently disclosed subject matter. Fig. 8 shows in isometric view a second connection element of the circular connector example of Fig. 7, in conjunction with a second coupler element of the coupler according to the second example of the presently disclosed subject matter. Fig. 9 shows in partial detail isometric view a first coupler element of a third coupler according to a third example of the presently disclosed subject matter. Fig. 10 shows in isometric view of a second coupler element of the coupler according to the third example of the presently disclosed subject matter. Fig. 11 shows in isometric view a portion of the second coupler element of the coupler example of Fig. 10. Fig. 12Ashows in isometric view a first connection element of a third example of a circular connector, in conjunction with a first coupler element of a coupler according to a fourth example of the presently disclosed subject matter; Fig. 12Bshows in isometric 0293857313-08 view a second connection element of the circular connector example of Fig. 12A, in conjunction with a second coupler element of the coupler according to the fourth example of the presently disclosed subject matter. Fig. 13 schematically illustrates a kit according to an example of the presently disclosed subject matter.

DETAILED DESCRIPTION As shown schematically in Fig. 1, a junction box or panel 2comprises a plurality of first connection elements 4each of which is a part of a respective circular connector 10 . A plurality of second connection elements 6,each of which is the respective second connecting part of the respective circular connector, are configured to be connected to the respective second connection elements 4.In at least this example, the second connection elements 6are each connected to a cable 8or the like, while first connection elements 4, for example in the form of plugs, are each connected to specific electrical or electronic components, for example in the form of a junction box, for example an electrical/electronic/avionics junction box, that can have different electrical ratings one to another, for example.

Each circular connector 10accommodates two parts of a respective electrical connection arrangement, one part of the electrical connection arrangement being accommodated in the respective first connector element 4,and the second part of the electrical connection arrangement being accommodated in the respective second connector element 6.Each respective electrical connection arrangement provides electrical and/or electronic continuity across the connector 10when the respective pair of first and second connection elements 4, 6,are axially fully engaged with one another.

For example, the electrical connection arrangement can be in the form of male and female connectors. For example, one part of the electrical connection arrangement can include a particular pin arrangement – for example an 8- pin arrangement in which the pins are arranged in three rows, while the other part of the electrical connection arrangement can include a complementary socket arrangement – for example an 8- socket 0293857313-08 arrangement in which the sockets are arranged in complementary positions corresponding to the pins.

However, the arrangement of electrical connections such as pins and sockets in each of the pairs of connection elements 4, 6can be such that first connection element 4 of some circular connectors 10could be physically compatible with the respective second connection elements 6of more than one circular connector 10 , which could to incorrect connections between a first connection element 4of one circular connector 10the respective second connection elements 6of a different, and thus incorrect, circular connector 10 , which in turn can result in the different cables 8being electrically coupled to the wrong components of the junction box.

According to an aspect of the presently disclosed subject matter, and in order to minimize the risk and preferably prevent accidental physical connection of the wrong first and second connector elements 4, 6(i.e. that do not belong to the same circular connector 10 ) together, respective accessories in the form of couplers are provided, and examples of which are disclosed below by way of non-limiting examples. In such examples, differently-coded couplers can be provided for a set of identical connectors, thereby essentially coding the generic connectors in a non-integral manner. In other words, the respective couplers are each non-integral with respect to the respective circular connectors, and the circular connectors can be formed and provided without such couplers being attached thereto; rather, the couplers can be affixed to the respective connectors when desired, and optionally the couplers can be removed from the circular connectors in a non-destructive way, enabling the circular connector to still interconnect the two connector portions thereof in the conventional manner.

It is to be noted that the couplers according to the presently disclosed subject matter are not an integral part of any circular connector per se, and each coupler is separate from, distinct and different from the circular connector per se.

Referring to Figs. 2 and 3, there is shown a circular connector 20(also referred to interchangeably herein as a cylindrical connector) according to an example of the presently disclosed subject matter. 0293857313-08 The circular connector 20comprises a first generally cylindrical connection element 40(for example in the form of a receptacle) and a second generally cylindrical connection element 60(for example in the form of a plug). Each of the first and second connection elements 40 , 60 , comprises a respective longitudinal central axis, such that the first connection element 40comprises a first longitudinal central axis LCA1and the second connection element 40comprises a second longitudinal central axis LCA2.

Fig. 2 illustrates the first and second connection elements 40 , 60in a disconnected configuration DC , in which the first and second connection elements 40 , 60are not full mated with one another and are electrically disconnected from one another, i.e., the respective two parts of the respective electrical connection arrangement, each part being accommodated in a different one of the first connection element 40and the second connection element 60 , are not in electrical or electronic communication. Thus, for example, in the disconnected configuration DCthe respective male pins of one connection element are fully disengaged from, or at least not fully received inside, the respective female sockets of the other connection element.

Fig. 3 illustrates the first and second connection elements 40 , 60in a connected configuration CC , in which the first and second connection elements 40 , 60are coaxially aligned so as to have a common connector axis CCA , and in which the first and second connection elements 40 , 60are fully mated with one another so as to permit electrical connection therebetween. In other words, in the connected configuration CCthe respective two parts of the respective electrical connection arrangement are in electrical or electronic communication. Thus, for example, in the connected configuration CCthe respective male pins of one connection element are fully received inside, the respective female sockets of the other connection element.

Such mating can include, but is not limited to, an arrangement of pin and socket connections, or other male-female electrical arrangements as known to the skilled person.

The first and second connection elements 40 , 60can further be provided with locking arrangement to help retain the connection elements 40 , 60in the connected configuration. The locking arrangements could, for example, take the form of helical threads provided on each of the first and second connection elements 40 , 60 , a bayonet fitting, a blind mate locking mechanism, or other locking arrangements known to the 0293857313-08 skilled person. In the event that helical threads are provided, a torque limiting mechanism can be additionally provided to prevent over-tightening of the connection between the first and second connection elements 40 , 60 .

At least one of the first and second connection elements 40 , 60 , for example the second connection element 60,can be provided with a locking ring 62 , which can be turned about the second longitudinal central axis LCA2to advance and fully lock the first and second connection elements 40 , 60together axially in the connected configuration CC . The locking ring 62can comprise an outer textured surface to enable a user to better grip the connection elements 40 , 60in order to enable ease of connection and disconnection. In at least some alternative variations of this example, the first and second connection elements 40 , 60can be provided with any suitable arrangement or preparation that is compatible with a tightening tool.

Furthermore, the first and second connection elements 40 , 60can be provided with alignment arrangement that compels the first and second connection elements 40 , 60 to be aligned circumferentially with respect to one another (when also co-axially aligned with one another) in order to enable the first and second connection elements 40 , 60to come together to provide the connected configuration CC . For example, the first connection element 40can be provided with a number of keys axially parallel with respect to the first longitudinal central axis LCA1 , and the second connection element 60can be provided with complementary keyways that are also axially parallel with respect to the second longitudinal central axis LCA2 . The various keys are complementary to the respective keyways and are circumferentially located with respect to the first and second connection elements 40 , 60such that when the first and second connection elements 40 , 60are properly aligned, the keys slide into the respective keyways enabling the first and second connection elements 40 , 60to interconnect in the connected configuration CC . In this manner, it is ensured that the respective parts of electrical arrangement are also aligned and can electrically connect with one another properly. On the other hand, if the first and second connection elements 40 , 60are not circumferentially aligned, the mismatched alignment arrangement, for example the mismatched keys and keyways will not allow the first and second connection elements 40 , 60to come together and the circular connector 20will be unable to transition to the connected configuration CC . Such 0293857313-08 alignment arrangements are integrally provided in the circular connector 20 , and are distinct from the couples of the presently disclosed subject matter.

While there can be many kinds of applications for circular connectors, in this particular example, the first connection element 40is of the kind to pass through a structural element such as a wall, barrier or the like, while the second connection element 60is of the kind to be connected to the end of a cable, fibre optic transmission line or the like.

The circular connector can, for example, be capable of transferring data, power, signals, or the like between the two connection elements 40 , 60 , for example via coaxial connectors or pin/socket connectors wherein at least some such pins can also be in the form of coaxial connectors.

Since, in at least some applications, multiple circular connectors, having the same internal electrical connection arrangement, can be used in a single application, for example in a connector box, bulkhead or the like, care must be taken in order to avoid connecting the wrong second connection element 60to the wrong first connection element 40 , to ensure correct electrical connections are made.

According to an aspect of the presently disclosed subject matter, and in order to minimize the risk and preferably prevent accidental physical connection of the wrong first and second connector elements 40 , 60to one another (i.e. to prevent physical connection of first and second connector elements 40 , 60that do not belong to the same circular connector 20 ), the generic circular connector 20can be provided with a coupler, a few non-limiting examples of which will now be described in conjunction with the drawings.

With reference to Figs. 4 to 6, there is provided a coupler according to a first example of the presently disclosed subject matter, generally designated 100 . The coupler 100comprises a first coupler element 100A , which is connectable to the first connection element 40 , and a second coupler element 100B , connectable to the second connection element 60 .

As will become clearer herein, the coupler 100comprises a unique engagement arrangement 140that allows only the matched pair of the first coupler element 100Aand the second coupler element 100Bto be coupled to one another, and generally prevents a 0293857313-08 respective first coupler element of one such coupler to be coupled to a respective second coupler element of a different coupler. Thus, the coupler 100essentially provides an external, or non-integral coding option to differentiate properly coded connectors from other connectors.

With particular reference to Fig. 5, in this example, the first coupler element 100A comprises a first arc-shaped member 110Aand a second arc-shaped member 120A . The first arc-shaped member 110Acomprises a respective first end 111Aand a respective second end 112A , while the second arc-shaped member 120Acomprises a respective first end 121Aand a respective second end 122A . In at least this example, the first end 111A of the first arc-shaped member 110Aand the first end 121Aof the second arc-shaped member 120Aare hingedly connected to one another via a pivot 130A , allowing relative pivoting motion between the first arc-shaped member 110Aand the second arc-shaped member 120Aabout the pivot 130A .

In at least this example, the angle subtended by each of the first and second arcshaped members 110A , 120Ais nominally 180°. However, in at least some alternative variations of this example, the respective first coupler element can include more than two arc-shaped members hingedly connected to one another, each subtending an angle of 180° or less, so that the sum of the angles subtended by the respective arc-shaped members is 360°.

The first coupler element 100Aincludes a respective first locking arrangement for selectively (and optionally reversibly) locking together the second end 112Aof the first arc-shaped member 110Aand the second end 122Aof the second arc-shaped member 120A.

The second end 112Aof the first arc-shaped member 110Ais provided with a cantilever projection 113Ahaving a stepped lug 117Aat the end of the cantilever projection 113A , while the second end 122Aof the second arc-shaped member 120Ais provided with a recess 123Ahaving a locking step 124A(not visible in the angle of view of Fig. 5, but comparable to the locking step 117Bshown in Fig. 6). 0293857313-08 In at least some alternative variations of this example, different locking arrangements can be provided, for example screws, zip ties, cable ties, latch mechanisms, butterfly lock plug, adhesive, nuts/bolts, rivets and so on.

When the first and second arc-shaped members 110A , 120Aare rotated about the pivot 130Aso as to bring the second ends 112A , 122Atowards one another, the cantilever projection 113Aenters the recess 123Aand the stepped lug 117Acreates a cantilever snap-fit with the locking step 124A , so as to lock the coupler element 100Ain a closed position. In this manner, the first coupler element 100Acan be fixedly fitted in a snug manner around the first connection element 40in a manner preventing relative translation or rotation between the first coupler element 100Aand the first connection element 40 .

Optionally, the snap-fit can be released by simply biasing the cantilever projection 113Aso that the stepped lug 117Amoves away from the locking step 124A , thereby permitting the cantilever projection 113Ato be removed from the recess 123Aand the first and second arc-shaped members 110A , 120Ato be rotated about the pivot 130Aso as to separate the second ends 112A , 122Afrom one another.

While in at least this example, the recess 123Ais provided on the second arcshaped member 120Aand the cantilever projection 113Ais provided on the first arcshaped member 110A , in at least some alternative variations of this example, the reverse arrangement can instead be provided, for example in which the recess is provided on the first arc-shaped member and the cantilever projection is provided on the second arcshaped member. In yet other alternative variations of this example, the pivot arrangement can be replaced with a second locking arrangement, similar for example to the first locking arrangement.

While in at least this example, the locking between the first and second arc-shaped members 110A , 120Ais provided by a snap-fit connection, in at least some other alternative variations of this example, different locking arrangements can be provided for interconnecting the arc shaped members together, for example other conventional locking arrangements known to the skilled person, for example as screws, nuts bolts, glue, adhesive, rivets other fixings and fittings and the like. 0293857313-08 The first coupler element 100Acomprises a first portion 140Aof the engagement arrangement 140 . The first portion 140Acomprises a first geometrical configuration, which in this example is provided by two radial recesses 142A , 144Alocated on a radially inner side RIof a circumferentially extending wall 115Aof the first arc-shaped member 110A .

In at least this example, the radial recesses 142A , 144Aeach have a uniform crosssection that extends axially parallel to the respective first longitudinal central axis LCA1.

In at least this example, the radial recesses 142A , 144Asubtend an angle α therebetween. The two radial recesses 142A , 144Aare provided on an axial end-surface 114Aof the first arc-shaped member 110A , and when connected to the first connection element 40 , the axial end-surface 114Ais arranged to face towards the second connection element 60 .With particular reference to Fig. 6, in at least this example, the second coupler element 100Bcomprises a first arc-shaped member 110Band a second arc-shaped member 120B . The first arc-shaped member 110Bcomprises a first end 111Band a second end 112B , while the second arc-shaped member 120Bcomprises a first end 121B and a second end 122B . The first end 111Bof the first arc-shaped member 110Band the first end 121Bof the second arc-shaped member 120Bare hingedly connected by means of a pivot 130B , allowing rotation thereabout. In at least some alternative variations of this example, the hinged connection can be replaced with any suitable locking arrangements can be provided, for example similar to the arrangement for selectively (and optionally reversibly) locking together the second end 112Aof the first arc-shaped member 110Aand the second end 122Aof the second arc-shaped member 120Aas disclosed above, mutatis mutandis, or alternatively screws, zip ties, cable ties, latch mechanisms, butterfly lock plug, adhesive, nuts/bolts, rivets and so on.

In at least this example, the angle subtended by each of the first and second arcshaped members 110B , 120Bis nominally 180°. However, it in at least some alternative variations of this example, the respective first coupler element can include more than two arc-shaped members hingedly connected to one another, each subtending an angle of 180° or less, so that the sum of the angles subtended by the respective arc-shaped members is 360°. 0293857313-08 The second coupler element 100Bincludes a respective second locking arrangement for selectively (and optionally reversibly) locking together the second end 112Bof the first arc-shaped member 110Band the second end 122Bof the second arcshaped member 120B.

The second end 112Bof the first arc-shaped member 110Bis provided with a recess 113Bhaving a locking step 117B , while the second end 122Bof the second arcshaped member 120Bis provided with a cantilever projection 123Bhaving a stepped lug 124Bat the end of the cantilever projection 123A .

When the first and second arc-shaped members 110B , 120Bare rotated about the pivot 130Bso as to bring the second ends 112B , 122Btowards one another, the cantilever projection 123Benters the recess 113Band the stepped lug 124Bcreates a cantilever snap-fit with the locking step 117B , so as to lock the coupler element 100Bin a closed position. In this manner, the second coupler element 100Bcan be fixedly fitted in a snug manner around the second connection element 60in a manner preventing relative translation or rotation between the second coupler element 100Band the second connection element 60 .

Optionally, the snap-fit can be released by simply biasing the cantilever projection 123Bso that the stepped lug 124Bmoves away from the locking step 117B , thereby permitting the cantilever projection 123Bto be removed from the recess 113Band the first and second arc-shaped members 110B , 120Bto be rotated about the pivot 130Bso as to separate the second ends 112B , 122Bfrom one another.

While in at least this particular example, the recess 113Bis provided on the first arc-shaped member 110Band the cantilever projection 123Bis provided on the second arc-shaped member 120B , in at least some alternative variations of this example, the reverse arrangement can instead be provided, for example in which the recess is provided on the second arc-shaped member and the cantilever projection is provided on the first arc-shaped member. In yet other alternative variations of this example, the pivot arrangement can be replaced with a second locking arrangement, similar for example to the first locking arrangement of the second coupler element. 0293857313-08 While in at least this example, the locking between the first and second arc-shaped members 110B , 120Bis provided by a snap-fit connection, in at least some other alternative variations of this example, different locking arrangements can be provided for interconnecting the arc shaped members together, for example other conventional locking arrangements known to the skilled person, for example screws, zip ties, cable ties, latch mechanisms, butterfly lock plug, nuts/bolts, glue, adhesive, rivets other fixings and fittings and the like.

As can be seen in Fig. 6, in at least this example, the first arc-shaped member 110Bis provided with a first cut-away portion 118Bin an outer surface thereof, and the second arc-shaped member 120Bis provided with a second cut-away portion 128Bin an outer surface thereof. The first and second cut-away portions 118B , 128Benable a user to contact the locking ring 62of the second connection element 60in order to carry out any necessary relative rotation, for example a twisting motion, between portions of the first and second connection elements 40 , 60which will enable connection ordisconnection, such as a helical threaded connection, bayonet connection or other connection known to the skilled person.

The second coupler element 100Bcomprises a second portion 140 B of the engagement arrangement 140 . The second portion 140Bcomprises a second geometrical configuration, which in this example is provided by two lugs 142B , 144Bprojecting radially outwardly from the first arc-shaped member 110B .

In at least this example, the lugs 142B , 144Beach have a uniform cross-section that extends axially parallel to the respective second longitudinal central axis LCA2.

In at least this example, the two lugs 142B , 144Bsubtend an angle βtherebetween. The two lugs 142B , 144Bare provided on an axial end-surface 114Bof the first arcshaped member 110B , and when connected to the second connection element 60 , the axial end-surface 114Bis arranged to face towards the first connection element 40 .

The cross-sectional profiles of each of the radial recesses 142A , 144Aare complementary to the respective cross-sectional profiles of respective lugs 142B , 144B .

As can be seen in Fig. 4, when both the first coupler element 100Aand the second coupler element 100Bare connected to their respective first and second connection 0293857313-08 elements 40 , 60 , the axial end surfaces 114A , 114Bare arranged to face towards one another.

Since in at least this example, the subtended angles αand βare the same, and since the cross-sectional profiles of each of the radial recesses 142A , 144Aare complementary to the respective cross-sectional profiles of respective lugs 142B , 144B, when the first coupler element 100Aand the second coupler element 100Bare brought together coaxially, with the axial end surfaces 114A , 114Bfacing each other, the lugs 142A , 144Aare arranged to enable them to slide into, or be received in, the respective recesses 142B , 144B .

However, if non-matching coupler elements 100A , 100Bare brought towards one another, where the angles αand βdo not match, and/or the cross-sectional profiles of each of the radial recesses are not complementary to the respective cross-sectional profiles of respective lugs, the lugs 142A , 144Awill not coincide with the recesses 142B , 144Band instead will collide with the axial end surface 114Bof the circumferentially extending wall 115B . This will limit the proximity of the respective mis-matched coupler elements 100A , 100B , and prevent the mis-matched coupler elements 100A , 100Bfrom being brought together to be fully coupled, and hence when the mis-matched coupler elements 100A , 100Bare connected to the wrong combination of first and second connection elements 40 , 60 , will prevent the wrong combination of first and second connection elements 40 , 60from being brought into the connected configuration. Accordingly, two connection elements which are provided with (and thus "coded" with) non-matching coupler elements, i.e., with non-matching geometrical configurations, physically cannot be fully connected to one-another, thereby preventing errors and accidental misconnection between the first connection element of one circular connector and the second connection element of a different circular connector.

Accordingly, when the properly matched first coupler element 100Aand the second coupler element 100Bare connected to the first connection element 40and the second connection element 60 , respectively, the engagement arrangement 140is configured to permit axial translation of the respective and properly matched first and second connection elements 40 , 60along the common connector axis CCAinto the 0293857313-08 connected configuration, conditional on at least the following conditions for engagement being fulfilled: a) the first geometrical configuration 140Ais complementary to, matches or corresponds to the second geometrical configuration 140Bat least in an axial direction parallel with common connector axis CCA , so as to fit together when brought together in an axial direction along the common connector axis CCA ;b) the first connection element 40and the second connection element 60are coaxially aligned along the common connector axis CCA ; andc) the first and second portions 140A , 140Bof the engagement arrangement 140 are in an engaging enabling position, in which they are oriented about the common connector axis at corresponding angular orientations so as to fit together when brought together in an axial direction along the common connector axis CCA .

The engagement arrangement 140essentially acts as a limiter preventing the connection elements 40 , 60when connected to the coupler elements 100A , 100Bfrom being brought into the connected configuration unless the conditions for engagement are fulfilled.

Alternatively or additionally, although in this example, the physical limit provided by the geometrical configurations is determined by a size of a subtended angle, it is envisaged that the limit can additionally or alternative also be provided by a non-matching size or cross-sectional profile, of a respective recess or lug.

Alternatively or additionally, although in this example, two lugs and recesses were provided, it is envisaged that there can alternatively be provided one, two, three, four, five or more recesses and lugs, which could be of varying sizes and shapes in profile.

Alternatively or additionally, although in this example, the lugs are provided on the first coupler element 100Aand the recesses are provided on the second coupler element 100B , it is envisaged that these can be provided in the opposite manner, or alternatively, a combination of lugs and recesses could be provided on each of the coupler elements 100A , 100B . 0293857313-08 Since the coupler elements 100A , 100Bare each provided with a snap-fit closure mechanism, when each coupler element 100A , 100Bis closed around the respective connection element 40 , 60 , a snap-fit locking connection is made, by which a snug, interference fit is created between the coupler elements 100A , 100Band each respective connection element 40 , 60 . Thus, each of the first and second coupler elements 100A , 100B , when connected to the respective first and second connection element 40 , 60 , is constrained with respect to the respective connection element in:- preventing relative motion in an axial direction along the respective central longitudinal axis; and- preventing relative motion in a radial direction from the respective central longitudinal axis.In at least some alternative variations of this example, each of the first and second coupler elements 100A , 100B , when connected to the respective first and second connection element 40 , 60 , is constrained with respect to the respective connection element in preventing relative motion in a circumferential direction about the respective central longitudinal axis.The at least this example, the coupler 100can be formed by injection molding or cast, for example. Alternatively, the coupler 100can be produced by additive manufacture such as 3D printing, or subtractive manufacture such as machining, or the like.In at least some examples, the coupler 100could be formed of a polymer material, such as a plastics material, or a metal material such as aluminium, steel, titanium, composite materials (for example fiber reinforced materials) or the like. The respective hinges can be formed of the same material as the remainder of the coupler 100or from a different material.In at least some examples, the coupler 100is configured to be snap-fit onto the outside of a circular connector, and so can be retrofit on a pre-existing circular connector, or could be used in combination with a new circular connector. Exemplary circular connectors in conjunction with which the first exemplary coupler 100could be used can include, but are not limited to, any one of a MIL-DTL-38999 circular connector, a micro miniature D38999 circular connector or any other suitable mating by turn connector.According to an aspect of the presently disclosed subject matter, there is provided a kit of couplers according to the first example, wherein each coupler 100in the kit has a 0293857313-08 respective engagement arrangement 140that is different from the respective engagement arrangement 140of the other couplers 100in the kit. This allows only the matched pair of the first coupler element and the second coupler element of the respective coupler to be coupled to one another, and generally prevents a respective first coupler element of one such coupler to be coupled to a respective second coupler element of a different coupler in the kit.In this manner a user can use such kit to selectively code each pair of connection elements of the respective circular connectors in a different manner with respect to one another, by using differently-coded couplers (i.e., in which the couplers each have respective engagement arrangements that are incompatible with respect to the engagement arrangement of the other couples, for example, having incompatible geometrical configurations). This feature enables a user to stock a single type of circular connector which is not specifically coded (in which the respective first connection elements are compatible with any second connection element of the other circular connectors), and to add-on the requisite number of cheap-to-produce, uniquely or differently coded couplers as required. In this way, an economical manner of producing a uniquely coded circular connector can be achieved, which can be tailored to the needs of the user.Optionally, matching pairs of coupler elements can be colour coded in the same colour, but different from colour of the colour code of other coupler elements having different geometrical configurations.Optionally, indicia or markings can be provided on an outer surface of the coupler elements to aid a user in aligning the coupler elements when making the electrical connections.

Referring to Figs. 7 and 8, a circular connector 220(also referred to interchangeably herein as a cylindrical connector) according to a second example of the presently disclosed subject matter, comprises a first generally cylindrical connection element 240and a second generally cylindrical connection element 260.

The first connection element 240is similar to the first connection element 40 described above, mutatis mutandis, except for the recesses 242and fastening holes 244 as will be described in more detail below. Hence, the above detailed description with 0293857313-08 respect to the first connection element 40applies mutatis mutandis to the first connection element 240.

Similarly, the second connection element 260is similar to the second connection element 60described above, mutatis mutandis, except for fastening arrangements provided inside, as will be described in more detail below. Hence, the above detailed description with respect to the second connection element 60applies mutatis mutandis to the second connection element 260.

As mentioned above, and as can be seen in Fig. 7, an annular axial end surface 241of the first connection element 240is provided with a plurality of recesses 242 arranged thereabout, optionally at equal angular intervals. Although in this example twelve recesses 242are shown, in at least some alternative variations of this example any number of recesses greater than one can be provided, before example an odd number or an even number of recesses. For example the first connection element 240can be provided with two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty or more than twenty recesses 242 , for example.

Additionally, the annular axial end surface 241is provided with two fastening holes 244 , which can be provided with an internal screw thread.

According to the second example, the respective coupler 200comprises a first coupler element 210Aand a second coupler element 210B . Furthermore, the respective coupler 200comprises a unique engagement arrangement 212that allows only the matched pair of the first coupler element 210Aand the second coupler element 210Bto be coupled to one another, and generally prevents a respective first coupler element of one such coupler to be coupled to a respective second coupler element of a different coupler.

The first coupler element 210Acomprises an annular ring 211Ahaving the same internal and external radial dimensions as the annular axial end surface 241of the first connection element 240 . The annular ring 211Ais provided with two countersunk fastening holes 214Aconfigured to align with the fastening holes 244of the first connection element 240 . Additionally, two countersunk screws 216Aare provided for 0293857313-08 affixing the annular ring 211Aof the first coupler element 210Ato the annular axial end surface 241of the first connection element 240via the countersunk fastening holes 214A and the fastening holes 244 .

The first coupler element 210Afurther comprises a first portion 212Aof the engagement arrangement 212 , which at least in this example is in the form of a bore 212A . In at least this example, the bore is configured to align with one of the recesses 242when the annular ring 211Aof the first coupler element 210Ais connected to the axial end surface 241of the first connection element 240 , while in the same position, the remainder of the annular ring 211Ais configured to cover, conceal and seal off the remainder of the recesses 242 .

Although in at least this example, a plurality of recesses 242 , are provided, in at least some alternative variations of this example, one or more circumferentially extending slots can be provided, which can allow more flexibility in the geometrical configuration which can be provided.

In at least some examples, the first coupler element 210A , in particular the annular ring 211A , has an axial thickness greater than or equal to a length of the protrusion or pin 212B , and there is no need for any recesses 242or slots in the annular axial end surface 241of the first connection element 240 ; thus, such recesses 242can be omitted in such examples.

Although in at least this example, two screws 216Aare provided to connect the first coupler element 210Ato the annular axial end surface 241of the first connection element 240 in at least some alternative variations of this example, more than two screws can be used, for example three or four screws, or more than four screws.

Additionally or alternatively, in at least some examples, only a single screw can be used in examples wherein the first connection element 240is provided with a shaped recess for receipt of the annular ring 211Aof the first coupler element 210Ain such a way so as to restrict relative movement between the first connection element 240and the annular ring 211Aof the first coupler element 210Ain at least one degree of freedom. 0293857313-08 With reference to Fig. 8, the second connection element 260is provided in an annular recessed internal portion thereof 262with two fastening arrangements (not shown), which can have a female screw thread arrangement configured to receive a screw.

A second coupler element 210Bcomprises an annular ring 211Bconfigured to fit inside the annular recessed internal portion 262of the second connection element 260 . The annular ring 211Bis provided with two countersunk fastening holes 214Bconfigured to align with the fastening arrangements of the second connection element 260 . Additionally, two countersunk screws 216Bare provided for connecting the annular ring 211Bof the second coupler element 210B , at least partially within the annular recessed internal portion 262of the second connection element 260 , to the fastening arrangements via the countersunk fastening holes 214B .

The second coupler element 210Bfurther comprises a second portion 212Bof the engagement arrangement 212 , which at least in this example is in the form of a protrusion or pin 212Bthat is configured to align with bore 212Awhen the second coupler element 210Aconnected to the second connection element is brought into engagement with the first coupler element 210Bwhen connected to the first connection element. The pin 212B is arranged to project in a direction parallel to an axis of the annular ring 211Bstarting at an axial end surface 218Bof the annular ring 211B .

The pin 212Bcan have any suitable cross-section that enables receipt of the pin within the bore 212A , including circular, non-circular, axi-symmetric or non-axi- symmetric.

In at least this example, the pin 212Bhas a cross-section that is complementary to the cross-section of the bore 212A.

Although in at least this example only a single pin 212Band bore 212Aare provided, in at least some alternative variations of this example any number of pins and bores can be provided, as long as their relative angular positioning matches, conforms, corresponds or is aligned thereby permitting the connection elements to be brought into the engaged configuration, in which the first and second connection elements 240 , 260 are coaxially aligned so as to have a common connector axis CCA , and in which the first 0293857313-08 and second connection elements 240 , 260are fully mated with one another so as to permit electrical connection therebetween.

Since in at least this example, the two parts of the engagement arrangement 212 , in the form of the pin 212Band bore 212A,are located at coincident angular locations about the respective axes LCA2 , LCA1when connected to the respective connection elements 260 , 240 , when the first coupler element 210Aand the second coupler element 210Bare brought together coaxially, with respective axial end surfaces 218A , 218Bof the first and second coupling elements respectively facing each other, the pin 212Bis arranged to slide into, or be received in, the respective bore 212Aand subsequently the respective recess 242 .

However, if non-matching coupler elements 210A , 210Bare brought towards one another, where the angular arrangement of the pin(s) 212Band bore(s) 212Ado not match and/or the cross-sectional profiles of each of the pin(s) are not complementary to the respective cross-sectional profiles of respective bore(s), when connected to the respective connection elements 240 , 260and when the electrical pins of the connection elements 240 , 260are aligned in a manner permitting contact therebetween when pushed together along the common connection axis CCA , the pin(s) 212Bwill not coincide with the bore(s) 212Aand instead will collide with the axial end surface 218Aof the annular ring 211Aof the first coupler element 210A . This will limit the proximity of the mis-matched respective coupler elements 210A , 210B , and prevent, the mis-matched respective coupler elements 2 10A , 210Bfrom being brought together to be fully coupled, and hence when mis-matched respective coupler elements 2 10A , 210Bare connected to the wrong combination of first and second connection elements 240 , 260 , will prevent the wrong combination of first and second connection elements 240 , 260from being brought into the connected configuration. Accordingly, two connection elements which are provided with (and thus "coded" with) non-matching coupler elements, i.e., with non-matching geometrical configurations physically cannot be fully connected to one-another, thereby preventing errors and accidental misconnection between the first connection element of one circular connector and the second connection element of a different circular connector. Accordingly, when the properly matched first coupler element 210Aand the second coupler element 210Bare connected to the first connection element 240and the second connection element 260 , respectively, the engagement arrangement 212 , which in 0293857313-08 this example comprises the pin(s) 212Band bore(s) 212A , is configured to permit axial translation of the respective and properly matched first and second connection elements 240 , 260along the common connector axis CCAinto the connected configuration, conditional on at least the following conditions for engagement being fulfilled: a) the first geometrical configuration, or bore(s) 212A , is complementary to, matches or corresponds to the second geometrical configuration, or pin(s) 212Bat least in an axial direction parallel with common connector axis CCA , so as to fit together when brought together in an axial direction along the common connector axis CCA ;b) the first connection element 240and the second connection element 260are coaxially aligned along the common connector axis CCA ; andc) the first and second portions of the engagement arrangement 212A , 212Bare in an engaging enabling position, in which they are oriented about the common connector axis CCAat corresponding angular orientations so as to fit together when brought together in an axial direction along the common connector axis.

The engagement arrangement essentially acts as a limiter preventing the connection elements 240 , 260when connected to the coupler elements 210A , 210Bfrom being brought into the connected configuration unless the conditions for engagement are fulfilled.

Alternatively or additionally, although in this example, the physical limit provided by the geometrical configurations is determined by the angular locations of the pin(s) and bore(s), it is envisaged that the limit can additionally or alternative also be provided by a non-matching size or cross-sectional profile, of a respective pin or bore.

Alternatively or additionally, although in this example, the bore is provided on the first coupler element 210Aand the pin is provided on the second coupler element 210B , it is envisaged that these can be provided in the opposite manner, or alternatively, a combination of bores and pins could be provided on each of the coupler elements 210A , 210B , in conjunction with respective modifications being made to the respective connection elements as necessary. For example, but without limitation, provision of recesses for at least partial receipt of an end of the pin. 0293857313-08 Since the coupler elements 210A , 210Bare each connected to the respective connection element by means of fasteners such as screws 216A , 216B , relative movement is constrained with respect to the respective connection element 240 , 260in: - an axial direction along the respective central longitudinal axis;- a circumferential direction about the respective central longitudinal axis; and - a radial direction from the respective central longitudinal axis.

As can be seen in at least this example, the pin 212Bcan taper at a distal end thereof, in order to provide ease of connection between the pin 212Band bore 212Awhen initially pushing the connection elements 240 , 260together due to an initial clearance fit therebetween, and subsequent snug connection when in an engaged configuration due to an interference or other close fit between a less tapered or wider portion of the pin 212B and the bore 212A .

Exemplary circular connectors in conjunction with which the second exemplary coupler could be used include, but are not limited to, any one of a MIL-DTL-389circular connector, a micro miniature D38999 circular connector or any other suitable mating by turn connector.According to an aspect of the presently disclosed subject matter, there is provided a kit of couplers according to the second example thereof, wherein each coupler 200in the kit has a respective engagement arrangement 212that is different from the respective engagement arrangement 212of the other couplers 200in the kit. This allows only the matched pair of the first coupler element and the second coupler element of the respective coupler to be coupled to one another, and generally prevents a respective first coupler element of one such coupler 200to be coupled to a respective second coupler element of a different coupler 200in the kit.In this manner a user can use such a kit to selectively code each pair of connection elements of the respective circular connectors in a different manner with respect to one another, by using differently-coded couplers (i.e., in which the couplers each have respective engagement arrangements that are incompatible with respect to the engagement arrangement of the other couples, for example, having incompatible geometrical configurations). This feature enables a user to stock a single type of circular connector which is not specifically coded (in which the respective first connection 0293857313-08 elements are compatible with any second connection element of the other circular connectors), and to add-on the requisite number of cheap-to-produce, uniquely or differently coded couplers as required. In this way, an economical manner of producing a uniquely coded circular connector can be achieved, which can be tailored to the needs of the user.Thus in at least some examples, a kit of couplers 200 as described above can be provided, comprising a plurality of matching pairs of coded rings with recesses and protrusions, such that at least two of these pairs are non-matching. In this way, a user can selectively code each standard pair of connection elements using differently coded couplers (e.g., having a recess(es) or a protrusion(s) or pin(s) at different angular locations).Optionally, matching pairs of coupler elements can be colour coded in the same colour, but different from the colour of the colour code of the other coupler elements having different geometrical configurations.Optionally, indicia or markings can be provided on an outer surface of the coupler elements to aid a user in aligning the coupler elements when making the electrical connections.

Referring to Figs. 9, 10 and 11, a coupler 300according to a third example of the presently disclosed subject matter, is similar to the second example of the coupler 200as disclosed herein, mutatis mutandis, except for the differences described below.

According to the third example, the respective coupler 300comprises a first coupler element 331Aand a second coupler element 311B . Furthermore, the respective coupler 300comprises a unique engagement arrangement 312that allows only the matched pair of the first coupler element 331Aand the second coupler element 311Bto be coupled to one another, and generally prevents a respective first coupler element of one such coupler to be coupled to a respective second coupler element of a different coupler.

In at least this example, and as will become clearer below, the engagement arrangement 312 , comprises a pin 312Band hole 332A(of a nut 330A ).Referring to Fig. 9, the first coupler element 331Acomprises a nut 330Aand a first annular ring 310A. The nut 330Acomprises a non-symmetrical recess or non-cylindrical shaped hole 332A 0293857313-08 passing therethrough. The nut 330Acomprises an outer polygonal shape, configured to be received within a recess 313Aprovided in the first annular ring 310A .

The recess 313Ais also polygonal and complementarily shaped with respect to the nut 330A . Furthermore, the polygonal shapes of the nut 330Aand recess 313Ahave at least two lines of symmetry, and thus the nut 330Acan be received in the recess 313A in at least two different orientations. In the illustrated example of Fig. 9 the nut 330Aand recess 313Ahave eight lines of symmetry and thus the nut 330Acan be received in the recess 313Ain any one of eight different orientations. In at least some alternative variations of this example, the respective nut and the respective recess have three, four, five, six, seven, nine or more than nine lines of symmetry and thus the nut can be received in the recess in respectively any one of three, four, five, six, seven, nine or more than nine different orientations.

The first annular ring 310Acan be provided as a separate component connected to an annular axial end surface of a first connection element of a circular connector, similar to axial end surface 241of the first connection element 240 , mutatis mutandis, or can constitute or be part of the axial end surface itself comprising the recess 313A . The recess 313Acomprises a seat for receipt of the nut 330A , which seat has an axisymmetric bore 312Acontinuing in a depth direction, configured to be aligned with the non- cylindrical or non-symmetrical shaped hole 332Aof the nut 330A .

In contrast with the outer polygonal shape of the nut 330A , the hole 332Ais non- symmetrical, as disclosed above. In at least this example the hole 332Ahas a flat wall part 339Ajoined to a concave cylindrical wall part 338A . The flat wall part 339Ais at a fixed spatial relationship with respect to the outer polygonal shape of the nut 330A . On the other hand, in view of the multiple lines of symmetry of this polygonal shape, the relative spatial orientation of the flat wall part 339Awith respect to the first annular ring 310A(and in at least this example, with respect to the first coupler element 331A ) can be any one of corresponding multiple orientations. Thus, in the illustrated example, since the nut 330Acan be received in any one of eight different orientations within the recess 313A , correspondingly the flat wall part 339Acan be oriented in each pone of eight different positions with respect to the first annular ring 310A(and in at least this example, with respect to the first coupler element 331A ). 0293857313-08 Referring again to Figs. 10 and 11, the second coupler element 310Bcomprises a second annular ring 318Band projection 312B(also referred to interchangeably herein as a pin or protrusion).

The second annular ring 318Bis configured to fit inside an annular recessed internal portion of a second connection element in the same way as with the annular ring of the second coupler element 210Band the second connection element 260of the second example, mutatis mutandis.

The second coupler element 310Bof the third example differs from the second coupler element 210Bof the second example in that the projection 312Bcomprises a shaft 332Bhaving a non-symmetrical (for example, non-cylindrical) shaft cross-section.

Furthermore, the shaft cross-section is complementarily shaped with respect to the hole 332A , and has flat wall part 339Bcorresponding to flat wall part 339A , and a convex cylindrical wall part 338Bcorresponding to concave cylindrical wall part 338A .

Thus, when the projection 312B , in particular the shaft 332B , is properly oriented with respect to the hole 332A , then the projection 312B , in particular the shaft 332B , can be axially passed through the hole 332A . By "properly oriented" is meant that the flat wall part 339Band the flat wall part 339Aare aligned with one another, and facing one another when the projection 312B , in particular the shaft 332B , is received in the hole 332A .

However, when the projection 312B , in particular the shaft 332B , is not properly oriented with respect to the hole 332A , then the projection 312B , in particular the shaft 332B , cannot be inserted through the hole 332A .

Thus, in a matched pair of first coupler element 331Aand second coupler element 310B , the projection 312B , in particular the shaft 332B , is properly oriented with respect to the hole 332A . Thus, the nut 330Ais received in a desired one of the multiple possible different orientations within the recess 313A , and correspondingly the nut 330Ais oriented with respect to the first annular ring 310A(and in at least this example, with respect to the first coupler element 331A ). Similarly, projection 312B , in particular the shaft 332Bis oriented in a matching manner with respect to the second annular ring 318B (and in at least this example, with respect to the second coupler element 311B ). 0293857313-08 Thus, in use, a user can independently choose for each pair of connection elements of a circular connector the orientation of each of the non-cylindrical pin 312Band nut 330A , such that they are configured to match, conform or complement one another on each pair of connection elements, but do not match one another between connection elements from different pairs of connection elements.

Since in this example, the pin 312Band hole 332Aof the nut 330Aare located at coincident angular locations about the respective axes LCA2 , LCA1when connected to the respective connection elements, when the two connection elements in a pair are brought together coaxially, with the pin 312Bprotruding towards the nut 330A , the pin 312Bis arranged to slide into, or be received in, the non-cylindrical c shaped hole 332A of the nut 330Aand subsequently the axisymmetric bore 312A .

However, if a pin 312Band nut 330Aof non-matching (i.e., improper) orientation are brought towards one another when connected to the respective connection elements and when the electrical pins of the connection elements are aligned in a manner permitting contact therebetween when pushed together along the common connection axis CCA , the pin(s) 312Bwill collide with the nut 330Aand not pass through the hole 332A . When mis-matched coupler elements are connected to the first and second connection elements, this will limit their proximity and will prevent the first and second connection elements from being brought into the connected configuration. Accordingly, two mis-matched connection elements which are "coded" with non-matching coupler elements, i.e. nonmatching geometrical configurations physically cannot be fully connected to one-another, thereby preventing errors and accidental misconnection.

Accordingly, when the properly matched nut 330Ais connected to the first connection element and the pin 312Bis connected to the second connection element, the engagement arrangement 312 , which in this example comprises the pin 312Band hole 332Aof the nut 330A , is configured to permit axial translation of the respective and properly matched first and second connection elements along the common connector axis CCAinto the connected configuration, conditional on at least the following conditions for engagement being fulfilled: a) the first geometrical configuration, or non-cylindrical 0293857313-08 b) shaped hole 332Aof the nut 330A , is complementary to, matches or corresponds to the second geometrical configuration, or pin 3 12Bat least in an axial direction parallel with common connector axis CCA , so as to fit together when brought together in an axial direction along the common connector axis CCA ;c) the first connection element and the second connection element are coaxially aligned along the common connector axis CCA ; andd) the first and second portions of the engagement arrangement 332A , 312Bare in an engaging enabling position, in which they are oriented about the common connector axis CCAat corresponding angular orientations so as to fit together when brought together in an axial direction along the common connector axis.

The engagement arrangement essentially acts as a limiter preventing the connection elements when connected to the coupler elements 330A , 310Bfrom being brought into the connected configuration unless the conditions for engagement are fulfilled.

Alternatively or additionally, although in this example, the physical limit provided by the geometrical configurations is determined by the particular orientation of the pin and bore, it is envisaged that the limit can additionally or alternative also be provided by a non-matching size or cross-sectional profile, of a respective pin or bore.

While in this example, the nut 330Ais octagonal allowing eight different orientations of the nut and respective pin 312B , it is envisaged that the nut could have any polygonal shape capable of having rotational symmetry of order at least two.

Alternatively or additionally, although in this example, the nut 330Ais arranged to be received on the first connection element and the pin is provided on the second coupler element 310B , it is envisaged that these can be provided in the opposite manner, or alternatively, a combination of bores and pins could be provided on each of the coupler element, in conjunction with respective modifications being made to the respective connection elements as necessary. 0293857313-08 Since the nut 330Aand pin 312Bare configured to be operably mounted to the respective connection elements such that relative movement is constrained with respect to the respective connection elements in:- an axial direction along the respective central longitudinal axis;- a circumferential direction about the respective central longitudinal axis; and - a radial direction from the respective central longitudinal axis.Exemplary circular connectors in conjunction with which the third exemplary coupler could be used include, but are not limited to, any one of a MIL-DTL-389circular connector, a micro miniature D38999 circular connector or any other suitable mating by turn connector.Although in at least this example, only a single protrusion 312Band nut 330Aare provided, in at least some alternative variations of this example, there can be provided more than one nut 330Aand more than one protrusion 312B , such as two or more of each, configured to be located at predetermined relative angular locations about the longitudinal central axes of the respective first and second connection elements configured to correspond with one another.While in at least this example the projection 312B , in particular the shaft 332B , and the hole 332Aeach have a respective flat wall part to provide the respective nonsymmetry, in at least some alternative variations of this example the respective projection, in particular the respective shaft, and the respective hole can have any suitable non- symmetric profile.According to an aspect of the presently disclosed subject matter, there is provided a kit of couplers according to the third example thereof, wherein each coupler 300in the kit has a respective engagement arrangement 312that is different from the respective engagement arrangement 312of the other couplers 300in the kit. This allows only the matched pair of the first coupler element and the second coupler element of the respective coupler to be coupled to one another, and generally prevents a respective first coupler element of one such coupler 300to be coupled to a respective second coupler element of a different coupler 300in the kit.In this manner a user can use such a kit to selectively code each pair of connection elements of the respective circular connectors in a different manner with respect to one another, by using differently-coded couplers (i.e., in which the couplers each have respective engagement arrangements that are incompatible with respect to the 0293857313-08 engagement arrangement of the other couples, for example, having incompatible geometrical configurations). This feature enables a user to stock a single type of circular connector which is not specifically coded (in which the respective first connection elements are compatible with any second connection element of the other circular connectors), and to add-on the requisite number of cheap-to-produce, uniquely or differently coded couplers as required. In this way, an economical manner of producing a uniquely coded circular connector can be achieved, which can be tailored to the needs of the user.Thus in at least some examples, a kit of different-coded said couplers 300as described above for the third example can be provided, comprising a plurality of non- cylindrical or non-axi-symmetrical pins or protrusions and a plurality of nuts having non- cylindrical or non-axi-symmetrical through-holes.Optionally, the kit could also include any necessary rings or fastenings as required.Optionally, indicia or markings could be provided on an outer surface of the coupler elements to aid a user in aligning these when making the electrical connections.

Referring to Figs. 12A and 12B, a circular connector 420(also referred to interchangeably herein as a cylindrical connector) according to a third example of the presently disclosed subject matter, comprises a first generally cylindrical connection element 440and a second generally cylindrical connection element 460 .

As shown in Fig. 12A, the first connector element 440is similar to first connector element 40described above, mutatis mutandis, and comprises a hollow housing portion 441surrounding a central void 444 . The central void 444is arranged to receive a one or more electrical connection elements 443 , which can be male, female or a combination of male and female, for example, a set of pins, recesses or similar arrangements. Once the electrical connection elements 443are received centrally within the central void 444 , there is an annular space around the electrical connection elements 443 , arranged to receive therein a first coupler element 410A .

The respective coupler 400according to the fourth example of the presently disclosed subject matter comprises a first coupler element 410Aand a second coupler element 410B . Furthermore, the respective coupler 400comprises a unique engagement 0293857313-08 arrangement 412that allows only the matched pair of the first coupler element 410Aand the second coupler element 410Bto be coupled to one another, and generally prevents a respective first coupler element of one such coupler to be coupled to a respective second coupler element of a different coupler.

The fourth example can be of particular use where the number of pins/sockets of the electrical connection arrangement is small. Alternatively, a circular connecter having a relatively large internal diameter and generally used for a large number of pins/sockets can be used with a relatively smaller number of pins/sockets when implementing the third example. In at least this example, the first coupler element 410Acomprises a central longitudinal axis AAand has a hollow cylindrical shape designed to allow passage of the electrical connection elements 443at least partially therethrough. At one end, the first coupler element 410Acomprises an annular flange 414A , comprising a plurality of boreholes 420Apassing through a thickness thereof. The first coupler element 410Acan be fixed within the annular recess surrounding the electrical connection elements 443 within the central void 444via fasteners such as for example screws 422Apassing through the boreholes 420Aof the flange 414Aand into the housing portion 441of the first connector element 440 .The first coupler element 410A , in particular the engagement arrangement 412 , comprises a first geometrical configuration, in the form of one or more grooves 412A arranged at select angular locations around, and recessed into, an inner circumferential surface of the hollow cylindrically shaped first coupler element 410A . These grooves 412Aextend in a direction parallel to the central longitudinal axis AAof the first coupler element 410A .As shown in Fig. 12B, the second connector element 460is similar to second connector element 60described above, mutatis mutandis, And comprises a hollow housing portion 461surrounding a central void 464 . The hollow housing portion 461 comprises a locking ring 462with a textured surface to enable a user to easily grip the second connector element 460and apply a twisting force or torque to permit changing between the connected configuration and the disconnected configuration of the connection elements 440 , 460 . The central void 464is arranged to receive a one or more electrical connection elements 463 , which can be male, female or a combination of male and female. For example, a set of pins, recesses or similar. Once the electrical connection 0293857313-08 elements 463are received centrally within the central void 464 , there is an annular space around the electrical connection elements 463 , arranged to receive therein a second coupler element 410B .In at least this example, the second coupler element 410Bcomprises a central longitudinal axis BBand has a hollow cylindrical shape designed to allow passage of the electrical connection elements 463at least partially therethrough. At one end, the second coupler element 410Bcomprises an annular flange 414B , comprising a plurality of boreholes 420Bpassing through a thickness thereof. The second coupler element 410B can be fixed within the annular recess surrounding the electrical connection elements 463 within the central void 463by means of fasteners such as screws 422Bpassing through the boreholes 420Bof the flange 414Band into the housing portion 461of the second connector element 460 .The second coupler element 410B , in particular the engagement arrangement 412 , further comprises a second geometrical configuration, in the form of one or more radially outwardly protruding keys 412Barranged at select angular locations around an outer circumferential surface of the hollow cylindrically shaped second coupler element 410B . These keys 412Bextend in a direction parallel to the central longitudinal axis BBof the second coupler element 410B .

Once the first and second coupler elements 410A , 410Bare fastened or fixed to the first and second connection elements 440 , 460respectively, the first and second connection elements 440 , 460can be brought together along a common central axis in the manner described in the examples above, mutatis mutandis, such that the keys 412Bare aligned with the grooves 412Aand are at least partially received therein. Thus, the coupler elements 410A , 410Band the connection elements 440 , 460must be coaxially aligned about a common central axis CCA , and rotationally oriented about that common central axis CCAin a manner such that the keys and grooves are aligned. Furthermore, the particular first and second geometrical arrangements, i.e. the keys and grooves 412B , 412A , must match or be compatible, for example, but without limitation, in terms of number, size and angular arrangement of the keys and grooves 412B , 412A .

Although in this example, screws are shown as the fastening arrangement for fixing the first and second coupler elements 410A , 410Bto the first and second connection elements 440 , 460respectively, in at least some alternative variations of this 0293857313-08 example, any suitable fastening or fixing arrangement known to the skilled person could be used alternatively.

Although in at least this example, keyways or grooves are provided on the first coupler element and keys are provided on the second coupler element, in at least some alternative variations of this example, the grooves and keys can be provided on the opposite components, and/or each of the first and second coupler elements can comprise at least one groove and at least one key, as long as the geometrical configurations are compatible with one another.

Additionally or alternatively, the keys need not extend longitudinally, and can simply comprise a protrusion which travels along the groove as the first and second coupler elements are brought between the connected and disconnected configurations.

Referring to Fig. 13, according to another aspect of the presently disclosed subject matter, a kit 500is provided, comprising a plurality of first coupler elements 510a , 510b , … , 510N , where the plurality is an integer N. The kit further comprises a plurality of second coupler elements 520a , 520b , … , 520N , where the plurality is also the integer N. Thus, the kit comprises N couplers 520 , each of which comprising a pair of first and second coupler elements.

The couplers 520are couplers for a plurality of circular connectors, each circular connector comprising a first generally cylindrical connection element having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, for example as disclosed herein mutatis mutandis. The first connection element and the second connection element have a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween. The first connection element and the second connection element also have a disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another.

As disclosed above, each coupler 520comprises a respective first coupler element and a second coupler element. Each first coupler element is connectable to a respective 0293857313-08 first connection element, and comprises a first portion of a respective engagement arrangement, which first portion comprises a first geometrical configuration. Each respective second coupler element is connectable to a respective second connection element, and comprises a respective second portion of the engagement arrangement, the second portion comprising a second geometrical configuration.

When the respective first coupler element and the respective second coupler element of one of the couplers are connected to the first connection element and the second connection element respectively of a circular connector, the respective engagement arrangement is configured to permit axial translation of the first and second connection elements along the common connector axis into the connected configuration, conditional on at least the following conditions for engagement being fulfilled: a) the first geometrical configuration is complementary to, matchesor corresponds to the second geometrical configuration at least in an axial direction parallel with common connector axis, so as to fit together when brought together in an axial direction along the common connector axis; b) the first connection element and the second connection element arecoaxially aligned along the common connector axis; and c) the first and second portions of the engagement arrangement are inan engaging enabling position, in which they are oriented about the common connector axis at corresponding angular orientations so as to fit together when brought together in an axial direction along the common connector axis.

At least one of the first coupler elements in the kit 500has a first geometrical configuration which is incompatible with at least one, and optionally all the other, of the second geometrical configurations of the second coupler elements in the kit.

The kit can comprise two or more couplers, such as 2, 3, 4, 5, 6, 7, 8, 9 or couplers for example.

Optionally each of the couplers within the kit 500can have unique geometrical configurations, such that the respective first coupler elements and the respective second 0293857313-08 coupler element have only a single unique one-to-one correspondence in terms of compatibility.

Optionally each of the first coupler element within the kit is geometrically compatible with only one second coupler element within the kit. Alternatively or additionally, each of the second coupler element within the kit are geometrically compatible with only one first coupler element within the kit.

The couplers in the kit or in any of the examples described above can, for example, be produced using additive manufacture, for example, by 3D printing. Materials which can be deposited include, but are not limited to, polymer material such as a plastic, metal material such as aluminium, stainless steel or titanium, composite materials (for example fiber reinforced materials) or any other material suitable for additive manufacture as known to the skilled person. Optionally, matching pairs of coupler elements could be colour coded in the same colour, but different from coupler elements having different or incompatible geometrical configurations.Optionally, indicia or markings could be provided on an outer surface of the coupler elements to aid a user in aligning these when making the electrical connections.

It should be noted that the word "comprising" as used throughout the appended claims is to be interpreted to mean "including but not limited to".

While there has been shown and disclosed examples in accordance with the presently disclosed subject matter, it will be appreciated that many changes can be made therein without departing from the scope of the presently disclosed subject matter as set out in the claims. 0293857313-08

Claims

- 46 - CLAIMS:

1. A coupler for a circular connector, the circular connector comprising a firstgenerally cylindrical connection element having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;the coupler comprising:a first coupler element connectable to the first connection element, the first coupler element comprising a first portion of an engagement arrangement, the first portion comprising a first geometrical configuration; anda second coupler element connectable to the second connection element, the second coupler element comprising a second portion of the engagement arrangement, the second portion comprising a second geometrical configuration; andwherein, when the first coupler element and the second coupler element are connected to the first connection element and the second connection element, respectively, the engagement arrangement is configured to permit axial translation of the first and second connection elements along the common connector axis into the connected configuration, conditional on at least the following conditions for engagement being fulfilled:(a) the first geometrical configuration is complementary to, matches or corresponds to the second geometrical configuration at least in an axial direction parallel with common connector axis, so as to fit together when brought together in an axial direction along the common connector axis; an(b) the first connection element and the second connection element are coaxially aligned along the common connector axis; and 0293857313-08 - 47 - (c) the first and second portions of the engagement arrangement are in an engaging enabling position, in which they are oriented about the common connector axis at corresponding angular orientations so as to fit together when brought together in an axial direction along the common connector axis.

2. The coupler according to claim 1, wherein each of the first and second couplerelements, when connected to the respective first and second connection element, is constrained with respect to the respective connection element at least:to prevent relative movement in an axial direction along the respective central longitudinal axis; andto prevent relative movement in a radial direction from the respective central longitudinal axis.

3. The coupler according to claim 1 or 2, wherein the engagement arrangement actsas a limiter preventing the connection elements when connected to the coupler elements from being brought into the connected configuration unless the conditions for engagement are fulfilled.

4. The coupler according to any one of claims 1 to 3, wherein at least one of the firstand second portions of the engagement arrangement comprises at least one projection and at least the other of the first and second portions of the engagement arrangement comprises a corresponding at least one recess; configured to receive the at least one projection;wherein, in use, when the coupler elements are connected to the respective connection elements:- the at least one projection extends in a direction parallel to the common connector axis; and- the at least one recess is configured to receive the at least on projection in the connected configuration.

5. The coupler according to any one of claims 1 to 4, wherein the first and secondcoupler elements are configured to be mounted to a cylindrical outer surface of the respective first and second connection elements. 0293857313-08 - 48 -

6. The coupler according to claim 5, wherein each of the first and second couplerelements comprises a hollow annular body comprising a central longitudinal axis.

7. The coupler according to claim 6, wherein the hollow annular body comprises atleast two arc-shaped members; andwherein the arc-shaped member are connected in a hinged manner at one end and configured with a snap-fit closure at the other.

8. The coupler according to claim 6, wherein the hollow annular body comprises atleast two arc-shaped members; andwherein the two arc-shaped member are configured at both ends with snap-fit closures.

9. The coupler according to any one of claims 1 to 4, wherein the first couplerelement comprises a first annular plate configured to be mounted to an axial end surface of the first connection element; andwherein the second coupler element comprises a second annular plate configured to be mounted to the second connection element;wherein the first annular plate comprises at least one through-bore passing through a thickness of said plate, and the second annular plate is provided with at least one protrusion configured to extend orthogonal to a surface of said second annular plate;wherein, when the conditions for engagement are fulfilled, the first and second annular plates can be brought together, such that the at least one protrusion is configured to be at least partially received in the at least one through-bore.

10. The coupler according to claim 9, wherein the at least one protrusion is configured to taper in a direction away from said second annular plate.

11. The coupler according to claim 9 or 10, wherein the at least one through-bore comprises at least two through-bores located at predetermined relative angular locations about a central axis of said first annular plate, and 0293857313-08 - 49 - wherein the at least one protrusion comprises at least two protrusions configured to be located at predetermined relative angular locations about a central axis of said second annular plate configured to correspond with the predetermined relative angular locations of the at least two through-bores.

12. The coupler according to any one of claims 1 to 4, wherein the first coupler element comprises at least one non-rotationally symmetric recess extending therein when viewed along an axis of the at least one recess; andwherein the second coupler element comprises at least one protrusion configured to be mounted to the second connection element, the at least one protrusion configured to extend parallel to an axis of the second connection element, wherein the at least one protrusion comprises a non-rotationally symmetric cross-section taken orthogonal to an axis of the protrusion;wherein, when the conditions for engagement are fulfilled, the at least one protrusion can be passed at least partially through the at least one recess.

13. The coupler according to claim 12, wherein the at least one protrusion is configured to taper along the axis thereof.

14. The coupler according to claim 12 or 13, wherein the at least one non-symmetrical recess comprises at least two non-symmetric recesses configured to be located at predetermined relative angular locations about the first longitudinal central axis of the first connection element, andwherein the at least one protrusion comprises at least two protrusions configured to be located at predetermined relative angular locations about the second longitudinal central axis of the second connection element configured to correspond with the predetermined relative angular locations of the recesses configured to receive the at least two protrusions.

15. The coupler according to any one of claims 1 to 4, wherein the first coupler element has a hollow cylindrical shape and comprises a central longitudinal axis, and 0293857313-08 - 50 - wherein the first geometrical configuration comprises at least one of a longitudinally extending groove or a protrusion; andwherein the second coupler element has a hollow cylindrical shape and comprises a central longitudinal axis, and wherein the second geometrical configuration comprises at least the other of the longitudinally extending groove or the protrusion;wherein, when the conditions for engagement are fulfilled, the first and second coupler elements, when fixed to the respective first and second connection elements, can be brought together, such that the protrusion is configured to be at least partially received in the groove.

16. The coupler according to claim 15, wherein the protrusion comprises a key extending longitudinally along the respective coupler element.

17. The coupler according to claim 15 or 16, wherein each of the first and second coupler elements further comprises a flange configured to facilitate fixing of the respective first and second coupler element within the respective first or second connection element.

18. The coupler according to any one of claims 15 to 17, wherein each of the first and second coupler elements comprises a plurality of protrusions or grooves located at predetermined angular locations about the respective central axis.

19. The coupler according to any one of claims 1 to 18, wherein at least a portion of the coupler is made from at least one of- a polymer material, optionally a plastics material; and- a metal, optionally any one of steel, aluminium or titanium;- a composite materials, optionally a fiber reinforced materials.

20. The coupler according to any one of claims 1 to 19, wherein the coupler is configured to be retrofitted on a pre-existing circular connector. 0293857313-08 - 51 -

21. The coupler according to any one of claims 1 to 20, being a coupler is suitable for use with any one of a MIL-DTL-38999 circular connector, a micro miniature D389circular connector or any other suitable mating by turn connector.

22. A circular connector comprising a first generally cylindrical connection element each having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;wherein the circular connector is operatively connected with a coupler as defined in any one of claims 1 to 21.

23. A circular connector comprising a first generally cylindrical connection element each having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;wherein the circular connector is configured to receive the coupler according to any one of claims 5 to 8;wherein the first coupler element is externally affixed with respect to the first connection element, and0293857313-08 - 52 - wherein the second coupler element is externally affixed with respect to the second connection element.

24. A circular connector comprising a first generally cylindrical connection element each having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;wherein the circular connector is configured to receive the coupler according to any one of claims 9 to 11;wherein the first connection element comprises an annular axial end surface comprising a plurality of bores, the annular axial end surface being configured to receive thereon the first annular plate; andwherein the second connection element is configured to receive the second annular plate.

25. The circular connector according to claim 24, wherein the plurality of bores comprises a plurality of blind-bores.

26. The circular connector according to claim 24, wherein the plurality of bores comprises a plurality of through-bores.

27. A circular connector comprising a first generally cylindrical connection element each having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in 0293857313-08 - 53 - which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;wherein the circular connector is configured to receive the coupler according to any one of claims 12 to 14;wherein the first connection element comprises an axial end surface configured to receive the first coupler element; andwherein the second connection element is configured to receive the second coupler element.

28. A circular connector comprising a first generally cylindrical connection element each having a first longitudinal central axis, and a second generally cylindrical connection element having a second longitudinal central axis, the first connection element and the second connection element having:a connected configuration in which the first and second connection elements are coaxially aligned so as to have a common connector axis, and in which the first and second connection elements are fully mated with one another so as to permit electrical connection therebetween; anda disconnected configuration in which the first and second connection elements are not full mated with one another and are electrically disconnected from one another;wherein the circular connector is configured to receive the coupler according to any one of claims 15 to 18;wherein the first connection element comprises a first annular space around one or more electrical connection elements, the first annular space being configured for receiving the first coupler element; andwherein the second connection element comprises a second annular space around one or more electrical connection elements, the second annular space being configured for receiving the second coupler element. 0293857313-08 - 54 -

29. The circular connector according to any one of claims 22 to 28, comprising any one of a MIL-DTL-38999 circular connector, a micro miniature D38999 circular connector or any other suitable mating by turn connector.

30. A kit comprising a plurality of couplers, wherein each coupler is as defined in any one of claims 1 to 21, wherein the first portion of the engagement arrangement of one of the plurality of couplers is incompatible with the second portion of the engagement arrangement of at least one other coupler of the plurality of couplers.

31. A kit comprising a plurality of couplers, wherein each coupler is as defined in any one of claims 1 to 21, wherein the first geometrical form of the first portion of the engagement arrangement of one of the plurality of couplers is incompatible with the second geometrical form of the second portion of the engagement arrangement of at least one other coupler of the plurality of couplers.

32. A kit according to any one of claims 30 to 31, wherein a colour of the first coupling element of one of the plurality of couplers does not match a colour of the second coupling element of at least one other coupler of the plurality of couplers.

33. A kit comprising a plurality of circular connectors as defined in claim 23 and a plurality of couplers as defined in any one of claims 5 to 8.

34. A kit comprising a plurality of circular connectors as defined in any one of claims to 26 and a plurality of couplers as defined in any one of claims 9 to 11;wherein, in use, the first annular plate is mounted to the first connection element such that the at least one through-bore of the annular plate is selectively aligned with a respective at least one bore of the plurality of bores in the respective connection elements; andwherein, in use, the at least one protrusion of the second annular plate is selectively mounted thereon, so as to extend orthogonally therefrom, at angular locations around the second annular plate corresponding to the at least one through-bore.0293857313-08 - 55 -

35. A kit comprising a plurality of circular connectors as defined in claim 27 and a plurality of couplers as defined in any one of claims 12 to 14;wherein, in use, the first coupler element comprising the non-symmetrical recess is fixed to the first connection element at a rotational orientation selected by the user; andwherein, in use, the at least one non-symmetrical protrusion is selectively fixed to the second connection element at a rotational orientation selected by the user, so as to correspond with the rotational orientation of the at least one recess selected by the user.

36. A kit comprising a plurality of circular connectors as defined in any one of claim to 28 and a plurality of couplers as defined in any one of claims 15 to 18. For the Applicants, REINHOLD COHN AND PARTNERS By: 0293857313-08