CH428882A - Method and tool for forming an electrical connection - Google Patents

Description

Method and Tool for Forming an Electrical Connection This addition is an improvement to the method and tool described in the Master Patent for forming an electrical connection between a conductor and a terminal. The present addition relates more particularly to a method and tool for making an electrical connection using insulated conductors, and its usefulness is particularly great when the techniques described in the main patent are only difficult to apply for removing the insulation. from the end of the conductor.

According to the present invention, the method for forming an electrical connection between an insulated conductor and a terminal by means of a connection member having between its opposite faces a width less than the thickness of the terminal and the core of the terminal. conductor in contiguous relationship and capable of being engaged with clamping on the Terminal by a sliding action, according to which an places the conductor transversely with respect to the Terminal at one end thereof and causes the connection member to slide on the Terminal to attack the conductor and to move it with the connecting member along the Terminal in order to trap the conductor between the connecting member and the Terminal, is characterized in that the insulation of the conductor is notched longitudinally near the Terminal to expose the core of the conductor which is pressed into direct contact with the Terminal when the conductor and the Terminal are pressed together between opposite faces of the connecting member .

The tool for implementing the method defined above, according to the present invention, comprises a body, a driving element movable longitudinally relative to a guide element facing an opening for a connection member. provided in the first body, the guide element being able to receive a connection member through said opening and ensuring the guiding of the connection member subject to the action of the drive element beyond a transverse passage. sal is intended to receive a conductor, in the direction of an anvil comprising a guide in line with the guide element and capable of being aligned on a Terminal, and is characterized in that the said guide element is formed with a notching device to score the insulation on the side of the conductor away from the core of the connecting member to expose the core of the conductor to the guide member.

The invention also covers the connection formed by the present method, in which an insulated stub of the conductor is clamped between the connecting member and the terminal and a bare core stub of the conductor is compressed between the terminal and the connecting member. connection. This connection is characterized in that the latter core has a longitudinal cut in the insulation on the side adjacent to the terminal, the core of the conductor being exposed through the cut and pushed against the terminal.

The invention is particularly suitable for its application to two conductors of the flexible Tinsel cord type, as will be seen later.

Forms of execution of the invention will now be described by way of example with reference to the appended partially schematic drawings, in which FIG. 1 is a schematic perspective view of the driving end of a tool according to the invention.

fig. 2 is a partial section and on a larger scale of the front part of the tool of FIG. 1 in line with a Terminal and with an insulated conductor, in the Position prior to the establishment of a connection.

fig. 3 is a cross-section through line 3-3 of FIG. 2 looking in the direction of the arrows.

fig. 4 is a view similar to FIG. 2 but showing the tool in an intermediate operating position.

fig. 5 is a traxLsversale section through line 5-5 of FIG. 4.

fig. 6 is an axial section of a clip-shaped connector used to hold a wire against a Terminal in a fully established connection.

fig. 7 is a cross section through line 7-7 of fig. 6.

fig. 8 is a partial perspective view of a portion of a strip of connectors joined end to end and making it possible to establish electrical connections according to the invention.

fig. 9 is a c816 view of the tool of FIG. 1, and fig. 10 is a partial perspective view of a short section of a flexible Tinsel cord.

A first embodiment of a corinector C in the form of a clip making it possible to make connections according to the invention is shown in FIG. B. Each Strip connector comprises a flat web 2 whose side walls 4 extend from its longitudinal sides. The edges of the side walls 4 are curved towards each other and towards the underside of the web 2. The distance between the edges of the side walls 4 and the underside of the web 2 is such that that the connector can tighten, as shown in figs. 6 and 7, a vertical Terminal 1 and bioquer 1'ame 5 of a conductor 3 against the surface of 1.a Terminal. The leading end of the core 2 has a recess 8 forming a cup towards the outside and fulfilling the dual function of a stress reduction element and of an insulation support for the protruding section of the conductor.

A hand tool for applying connectors of the type shown in FIG. 8 in order to establish connections (fig. 6 and 7) is represented in fig. 9 and comprises a descending handle 10 supporting on its upper side a pneumatic cylinder 12. The tool contains a mechanism for advancing successive connectors forming a Strip from a reel or other suitable source and leading from the Band into a Position facing a punch, itself driven by the piston rod of the pneumatic cylinder 12. The mechanism of this tool is well known and it is only the nose of this tool which is of interest to the Implementing the process that is the subject of this addition. It follows that Beul the nose of the tool will be the subject of a detailed description. Two flat covers 14 enclose the mechanism which actuates the various transfer devices and the punch which will be described later.

The nose of the tool is shown in FIG. 1 and comprises a Chassis Plate 18 on the front end of which is mounted a chuck block or anvil 20. The chuck block has a T-shaped upper portion comprising a rib 22 and a head 24. The thickness of the chuck head 24 is such that the connector can be brought over this projecting part with a hard friction fit. The head 24 ends slightly before reaching the anterior end of the block 20 by a stripped surface 26 beyond which an arm 32 extends forwards forming an extension of the rib 20 and can be placed against 1 end of Terminal 1, as shown in fig. 2. Plates 28 are fixed to each side of the chuck block 20 and are provided with elastic fingers 30 curved inwards and passing on each side of the arm 32 to come into contact with the sides of the Terminal 1 and thus facilitate the task. of the worker for the 1st

maintaining the tool against the Terminal. A cavity 34 for receiving a conductor is directed downward and rearward through the head 24 of the mandrel block, emerging in the rib 22 and opening to the right of the head.

A punch 38 constituting a connector pusher is moved back and forth along a T-shaped projection 44 on the upper end of a neck transfer slider 42 located at the rear of the block 20 and on the T-head 24 of the chuck. A recess is formed in the leading end of the punch 38 and a terminal connector fits into this recess During the movement of the punch, as shown in FIG. 4. Connectors are loaded onto projection 44 of cross slider 42 when cross slider 42 is in the down position and aligned with a strip of connectors on a feed path indicated generally at 49. Lowering of transfer slider 42 is ensured by a lever 46 itself actuated by the piston rod of the pneumatic cylinder 12. The strip of connectors is advanced to a position in which the movement of which a finger in advance comes into Engagment with the Strip of connectors. The block 50 is driven by the pneumatic cylinder 12. On the upstroke of the smooth neck 42, the head connector is severed from the Band and brought into the path of the punch 38.

An eastic finger 62 on the upper side of the tool is arranged to bear against the surface of a bollard when the tool is brought against its end, and this finger extends from a block 60 which straddles the path of the reciprocating movement of the punch and which is itself mounted on a block 61 fixed to the chassis plate.

A groove 64 is formed in the upper surface of the head 24 of the T-projection and slopes rearwardly and downwardly from a point near the front end 26 of the head 24 upwards. recess 34 and inside the latter. Near recess 34, groove 26 slopes more steeply, as indicated at 68, and merges with the forward side of recess 34 to provide a smoothly curved transition surface. As seen more clearly in FIG. 3, a V-rib 66 is formed on the bottom of the recess 64 centrally between its two walls. The top of the rib 66 is sharpened to allow it to score the insulating sheath 3 of a conductor when the latter is pulled forward through the groove.

In service, the parts normally occupy the position shown in fig. 1 and a Terminal is on projection 44 of cross slide 42. 30 come to bear on the sides of the bollard while the elastic finger 62 rests against the upper side of the latter. An operator inserts the end of an insulated conductor into recess 34 (see Fig. 2) and depresses detent 30 to admit compression into cylinder 12 and impart forward motion to punch 38. This punch 38 first passes over the upper end 44 of the transverse slide 42 to push the slide connector and over the head 24 of the chuck. As the punch continues to move, it pushes the connector against the head 24 and past the recess 34 where. the leading end of the connector engages the insulation 3 of the conductor. This insulation is compressed in the groove 64 of the mandrel head 24 and as the connector progresses forward the insulated conductor is compressed more and more due to the curved transition section 68 until so that the insulated conductor is effectively deformed and fills the entire cross section of the groove (see FIG. 5). The insulation On the underside of the conductor is pushed against the sharp edge of the rib 66 which cuts an axial cut in the insulation. The conductor end is pulled through groove 64 as the connector advances and is thus scored to the end.

As Connector C moves relative to Borge 64 and past it to Terminal 1, it is forced to close 61astically, as seen in FIG. 7, to receive the conductor drawn from the Borge 64 and the conductor being confined between the core 2 and the opposite surface of the Terminal. The relatively large force on the conductor causes it to flatten and separate from the insulation along the notch made by the sharp edge of the rib 66. This results in the conductor core 5 of the conductor being pushed against the surface of the conductor. Terminal Terminal So that after the connector has come to the Rest Position on the Terminal, there is a direct electrical connection between Core 5 and the Terminal, as seen in FIG. 7.

Advantageously, the physical properties of the material forming the connector are such as to allow this connector to behave like a spring capable of compensating for the relaxation of the insulation, which would otherwise have caused a lowering of the pressure. contact between the first core 5 and the Terminal.

The process described is advantageously applicable to any insulated conductor with insulation which may be cut by the sharp edge of rib 66, for example comprising insulation of polyamide resin, polytetrafluoroethylene or a conventional fibrous material. A special advantage is that the contact area between the terminal and the conductor core is surrounded by highly compressed insulation material which is resiliently urged by the connector against the core 5 and the surface of the terminal. . Ort thus establishes a substantially continuous bond between the environment and the contact zones, protecting against adverse media such as humidity or corrosive gas.

The method described is particularly useful for establishing a connection between a terminal and a wire of the flexible Tinsel cord type. A conductor of this type is represented in FIG. 10 and comprises several strands in the form of extremely small ribbons 70 each of which RTI ID="0003.0274" WI="4" HE="3" LX="378" LY="2045"> is wound helically around a core continuous 72 made of fibers, usually natural fibers such as cotton. The individual strands 70 are covered with an inner insulating sheath 74 and an outer insulating sheath 76. These insulating sheaths can be made of a natural fiber or at least one of them can be made of a plastic material. This type of conductor is used when maximum flexibility is desired, but this wire has always caused serious trouble when it came to making an electrical connection. In effect, the conductor does not lend itself to conventional stripping techniques since the conductor core is formed of helical ribbons surrounding the fibers 72, so that any attempt to nick the wire generally results in the sectioning of strands. Flexible Tinsel conductors can be connected to terminals as described, because the cutting edge 66 cuts the insulating sheaths 74 and 76 as the conductor is pulled through the groove 64. The helical strands of the conductor are then exposed and compressed against the surface of the Terminals as shown in fig. 7, through the axial cut in the sheaths.

Although in the described embodiment, a sharp edge 66 is used to make the axial cut in the insulating sheath 3 of the conductor, it has been found that for certain types of insulation such a sharp edge is not necessary. When the insulating sheath is made of a plastic material having a high susceptibility to notching, and tending to split; after extension, it becomes possible to form the notch by simply pulling the wire over the surface of the anvil. that it is held in the flattened position by the constraint of the connector. In these cases, the insulation is stretched on the underside to such a degree that the insulation separates on the opposite sides at the core side and at the anvil side. 0n will see In fig. 5 that the isolation is much less compressed or constrained across the width of the anvil edge, such that separation of the isolation cannot occur along the sides considered.

An important function of the Borge 64 is to center the conductor with respect to the cutting edge 66, but other means can accomplish this task. For example, several cutting edges may be installed across the width of the anvil or chuck so that the driver inevitably passes over one or other of said edges.

Claims (11)

CLAIMS I. Process for forming an electrical connection between an insulated conductor and a terminal by means of a connection member having between its opposite faces a width less than the thickness of the terminal and the core of the conductor in contiguous relationship and capable of being engaged with clamping on the Terminal by a sliding action, according to which an places the conductor iso16 transversely with respect to the Terminal at one end of the latter and causes the connection member to slide on the Terminal to attack the conductor and to move it with the connecting member along the Terminal in order to trap the conductor between the connecting member and the Terminal, characterized in that the insulation of the conductor is notched longitudinally to near the Terminal to expose the core of the conductor which is pressed into direct contact with the Terminal when the conductor and the Terminal are pressed together between opposite faces of the connecting member. II. Tool for implementing the process according to claim 1, comprising a body, a drive element movable longitudinally relative to a guide element facing an opening for a connection member formed in the first body, the guide capable of receiving a connecting member through said opening and ensuring the guiding of the connecting member subjected to the action of the driving element beyond a transverse passage intended to receive a conductor, in the direction of an anvil comprising a guide in line with the guide element and capable of being aligned on a terminal, characterized in that the said guide element is formed with a notching device for notching the insulation on the side of the remote conductor of the core of the connection member in order to expose the core of the conductor to the guide element. III. Electrical connection made by the method of claim 1, wherein an iso16 section of the conductor is clamped between the connection member and the terminal, and a stripped core section of the conductor is compressed between the terminal and the connection member, characterized in that the latter section has a longitudinal cut in the insulation on the side adjacent to the terminal, the conductor core being exposed through the cut and pushed against the terminal. SUB-CLAIMS 1. Process according to claim I, characterized in that a guide of the connection member is placed in alignment with the terminal at the end of the latter, this guide presenting at the end opposite the terminal an anvil , by placing the conductor transversely with respect to the terminal and the anvil, by pushing the connecting member against the anvil to engage the conductor between the connecting member and the anvil and to move the conductor with the connecting member along of the guide to compress the first conductor between the connecting member and the first guide and thus form in the insulation of the conductor a longitudinal cut adjacent to the guide Jans the portion between the connecting member and the first guide in order to expose the core of the conductor, and moves the connecting member with the guide conductor over the terminal to clamp the conductor core in direct contact with the terminal. 2. Process according to claim 1, characterized in that the portion of the conductor between the connection member and the terminal is subjected to increasing compression during its application to the terminal or movement along the guide. 3. Method according to sub-claim 1, characterized in that the guide has a Borge in which an initially deforms the conductor as the connection member moves beyond this Borge. 4. Method according to sub-claim 3, characterized in that said Borge has a notching device which attacks the insulation on the side far from the core of the connecting member. 5. Method according to sub-claim 4, characterized in that the conductor is progressively flattened after said notch to push its core through the notch. 6. Tool according to claim II, characterized in that the scoring device comprises a cutting tool which attacks the insulation on the 6th side of the core of the connecting member. 7. Tool according to claim II, characterized in that the guide element RTI ID="0004.0274" WI="4" HE="4" LX="1587" LY="667"> is formed with a ramp s extending forward from the Cross Conductor Passage and capable of progressively compressing the conductor between the connecting member and the ramp as the connecting member moves forward. B. Tool according to claim 11, characterized in that the guide element has a rib extending forwards from the transverse passage to receive the conductor while the connecting member moves forwards opposite the Cross passage. 9. Tool according to sub-claim 8, characterized in that the depth of said Borge decreases forwards from the Cross Passage. 10. Tool according to sub-claim 9, characterized in that the Borge has a bottom having a surface of gradual transition from a front wall of the Cross Passage. 11. Tool according to sub-claims 8, 9 and 10, characterized in that a cutting edge extends upwards from the bottom of the Borge to attack the insulation of the conductor on a side remote from 1 soul of the connecting device.