CN103178372A - Plug pins formed in extrusion method - Google Patents

Abstract

The invention relates to a plug pin having a connection end for connecting to a power supply stranded wire and an extruded middle area leading from the connection end to a contact end on the socket contact side. For this purpose, the connection end is designed as a clamping end and the middle area is designed to be hollow.

Description

Plug pins formed in extrusion method

This application is a divisional application of the parent application of the applicant's invention titled "Plug Pins Formed in Extrusion Method". The application number of the parent case in China is 200880109927.1, and the application date is August 12, 2008.

technical field

The invention relates to a plug pin as well as its production and application.

Background technique

Plug pins are well known. It is applied to the power plug of electrical appliances to realize the connection between the conductive twisted wires of the power cord as a conductive connection in the socket.

For this purpose, the plug pins are typically fastened in a plug bridge in which the plug pins are enclosed in a non-conductive plastic with a geometrically correct mutual spacing and with the correct protrusion height. Plug bridges can have ground spring clips and in some applications filter elements or similar. When producing the power cord applied to the plug bridge, the insulation layer of the twisted wire of the power cord is removed at first, and then fixedly connected to the connecting end of the plug pin. After fixing the strands, a PVC insert, typically produced by the injection molding method, is formed around the connection area. The inlay body insulates the contact connections and can be provided with strain relief or the like.

The power cords and plug bridges of many electrical appliances needed in daily life, as well as used parts such as plug pins are mass-produced products. The production of corresponding components is subject to enormous cost pressures. Despite the cost pressures, a high level of safety must also be ensured, since errors in production could put the user of the plug pins at risk of life, ie through a fire or by electrical shock to the user due to improper use.

A large number of plug pins are already known. Typical in the prior art is the undesired formation of lead alloys with the usual use of brass as raw material.

DE 10 203 171 A1 already discloses an electrical plug pin with a conductive core produced in an extrusion process, wherein the electrical plug pin is intended to be inserted into a socket and comprises a conductive core with a connection area for the electrical connection of the socket and for connecting electronic The interface area of the part. In DE 10 203 171 A1 the conductive core is produced in an extrusion process. The conductive core is used especially for European sockets and is surrounded by an electrically insulating layer in the central area.

The conductive plug connector mainly consists of two plug connectors of the same design or a plug connector and a connection part of the same design, wherein an outwardly protruding, at least A flange-shaped position stop extending approximately over the entire circumference of the plug-in connector and ending in a sharp corner is disclosed in DE 103 23 850 C2. Wherein the position stop is formed by the ring-shaped outer area of the end of a circular closure part integrally formed on the end of one of the two parts or of the end of a circular separating part between the two parts form. Although chipless machining was proposed, extrusion was not explored in detail.

Extrusion is mentioned in DE10041516A1, but it relates to electrical connections for high currents, which have sockets (Aufnahme) for permanently fixing the conductors of the connection and elastic plug contacts for connection to mating plugs. point. Spring ends shown are not suitable for power plugs. In addition, a multi-component structure is described.

US-PS 4597281 discloses the production of brush connectors by extrusion forming a metal alloy. Furthermore, the brush connector is produced in a multi-stage process with two opposing ends having different diameters.

Therefore, it is desirable to provide a power socket that achieves higher safety at a lower overall cost.

Contents of the invention

It is therefore the object of the present invention to provide a new industrially applicable plug pin.

The objects of the invention are given in the independent claims. Preferred embodiments are given in the dependent claims.

Accordingly, the present invention proposes, in a first basic idea, a plug pin with a connection end for connecting a power supply strand and an extruded middle region leading from the connection end to the connection end on the socket connection side, wherein The connecting end is designed as a clamping end and the central region is at least substantially hollow.

Therefore, the first basic idea of the invention is that a plug pin can be substantially improved in that a hollow shape of the central region is provided simultaneously with the formation of the clamping end. The central region, even if it is formed hollow, has a change in the material properties brought about by extrusion. This applies in particular when the pins of the plug are made of solid material, which may be the case but is not required. The change in properties of the central region that occurs during extrusion unexpectedly leads to an improvement in the mechanical stability of the central region, so that even in the case of relatively thin walls in the central region and thus with considerable material savings There are also no breakages or other deformations that occur in the falling drum test (Trommelfallversuchen), in which the plug bridges are regularly bent in order to pass the test.

It has been found that excessive changes in the material properties, in particular the ductility and the hardness, which occur through the necessary and for the person skilled in the art, the extrusion deformation which is carried out in multiple stages which are reasonable for the extrusion deformation, can possibly be Set up the heat treatment process. This can be achieved by thermal processing of prefabricated or partially produced plug pins, or by hot extrusion, ie extrusion of preheated material.

The processing steps that occur during the production process also do not lead to deformation of the usually hardened intermediate region formed by extrusion. Equally, unintentional clamping on the connection ends can also occur, which is undesirable because clamping is a highly dynamic process and hardening by deformation, which can even lead to brittle or hardened materials, is typical here do not want to see. However, it has been found that, despite the improved intermediate region, there can still be clamping in the connection region, which in turn can be attributed to the presence of other deformation conditions there. A plug pin formed in this way makes it possible to provide a lighter plug pin, which in particular requires less raw material. Due to the fact that the cavity in the middle area can be additionally closed in the direction of the plug insert by suitable clamping, that is, during normal clamping (as it is achievable in industry standards), the sealing of the plastic fluid is such that neither There is no concern about the PVC protruding into the cavity, nor the resulting additional material consumption. The connection area also no longer needs to be insulated by additional material. This not only leads to a reduction in the price of the entire plug through material savings, but also saves transport weight, which is of great significance for global transport, for example when the plug bridge, power cord and electrical appliances are manufactured separately at other locations and later The case where the finished appliance is to be shipped to distant users.

It is particularly preferred if the connection is extended on the side of the power strand. This simplifies the connection, ie lead-in, of the power strands. In principle, the insertion of the power strands can also be simplified by means of predetermined plastic funnels, which can be integrally formed with the plug base plate into which the plug pins are injected, and/or the predetermined The plastic funnel is fixed to the base plate of the plug bridge. Preferably, however, instead and/or preferably additionally, the connection ends themselves are directly extended. This can be achieved by creating a funnel-shaped profile, which is identical to the arrangement of the clamping tabs, resulting in a V-shaped or U-shaped clamping part. The actual shape of the connection can also be determined depending on the plug pins of each country, since for a given plug pin geometry it is preferably possible to insert the power strands in different ways in the base plate. On this point reference is made to the difference between German plug pins and British plug pins.

Furthermore, the pins of the plug can be defined not only for connection to the neutral or phase conductor (neutral and live), but also for connection to the ground or earth. A plug pin can also be understood here as a plug pin for a conventional 240V or 120V alternating current, as well as a plug pin for a three-phase current.

In the case of the funnel-shaped preferred expansion of the connection end, a standard expansion can be provided, wherein the deformation means can be introduced from the connection end. In particular a multi-stage acting punch, like a (hydrostatic) acting flow, can be used as the deformation means. It should be noted that the invention allows both possibilities, but a multi-stage forward extrusion is particularly preferred.

As mentioned above, the safety plug (plug with protective earth contact) is preferably designed for power plugs, especially for European standard double safety plugs or safety plugs.

Since the plug pins are defined and suitable for use in a plug bridge, the molding is preferably carried out in a sealing manner in the area of the connection end which is surrounded by plastic when forming the plug bridge, this shaping prevents twisting of the plug pins in the plastic block of the plug bridge or rotate freely and/or be pulled out. To prevent loosening due to twisting, roll-on, press-in or cast-in, i.e. snap off in the area of the plug bridge plastic block or provide for circularly symmetrical shaping of the plug pins in the area surrounded by the plug bridge plastic block . Molding can be effected during extrusion deformation, eg pressing the material towards an external extrusion die (master die) and/or in subsequent processing.

The plug pins can be made of solid material. In this case, the plug pin is formed into a hollow central region by a suitable pressing punch or pressing fluid. This can be done by means of a pressed punch or by pumping in a fluid. Alternatively, a hollow element can also be used as a starting point, ie an extruded blank of suitable length is provided. During the pressing and/or in a step different therefrom, the contact-side end can be deformed such that a standard rounding results. This prevents the penetration of foreign matter without any problems, so that the user cannot be injured by touching, for example, damp or inherently conductive objects such as thin copper wires, which protrude at the tip and lead therethrough to the phase conductor.

The use of solid material is preferred if the plug pin is not designed to be hollow or not completely hollow at its socket insertion end, but solid material is also present there. Advantageously, a plug bridge formed by the plug pins performs a pull-out test for testing the behavior of the plug pins when they are continuously pulled out of the socket under full load. Such tests can cause damage to the pins of the plug by arcing during extraction. Durability under such conditions is greatly improved by leaving a thickened end area towards the socket. Furthermore, at least preferably, the end region is selected in such a way that it completely contacts the connection region in the socket.

It should be noted that extrusion molding alone does not have to be performed, but it is preferable because it is very advantageous in manufacture.

The dimensions of the hollow area are chosen such that the weight of the central area, which is considered to be insulating, is at most 70%, preferably less, particularly preferably at most 40%, of the weight of a solid body with the same outer dimensions. The advantages obtained with the plug pin according to the invention, in particular with regard to the saving of expensive metal material, will be reduced if the weight saving is less than 30%. Conversely, for a wall thickness that is too small, the stability of the plug pins is affected. However, it is conceivable that, with suitable materials, a greater weight reduction compared to the central region given here is preferably also possible. In principle, the weight should be reduced as much as possible, but it must be ensured that the necessary stability tests such as the falling drum test and similar tests can still be passed. The above describes the case where it is possible to realize without problems, but the present invention is not limited thereto.

The plug pins are preferably made of brass or stainless steel. Extruded materials that withstand the necessary dimensions without breaking or other damage may also be used.

Furthermore, the invention can preferably use brass as raw material, provided that the copper content is sufficiently high. In practical tests the results were very satisfactory with a copper content of 85%, it is also possible to consider brass types with a smaller copper content, for example brass types with only 70% copper content. Furthermore, it is not necessary to add lead (Pb) alloys, resulting in lead-free plug pins. Furthermore, the percentage content of copper is not meant to be limiting, but only preferred. Raw materials that have been preheated in a suitable, known manner for extrusion are used where appropriate. This preferably also applies to raw materials other than brass.

It is also conceivable for the invention to use different materials than those specified according to national or international standards and, if necessary, to use materials which are not yet usable for legal reasons if the national standards change. The availability of metals other than brass, in particular stainless steel, has already been explained and disclosed in detail; a preferred embodiment is given here, in which the plug pin forms the contact part solidly in the front region, ie when introduced into the socket. Surface treatments such as nickel plating can reasonably be applied to the plug pins of the present invention and are generally preferred. This also happens to apply to the stainless steel plug pins.

The cavity can be designed such that there is solid material on the outside, ie the part of the plug pin protruding beyond the base plate. This is beneficial for implementing security testing.

Also claimed are a plug bridge with at least one plug pin according to the invention, a power cord with such a plug bridge and an electrical appliance with such a power cord. Also protected is the method for producing the device according to the invention.

Description of drawings

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. in:

Figure 1a is a longitudinal sectional view of a plug pin according to the invention in the state of being injected into a plug bridge substrate;

Figure 1b is a cross-sectional view through different heights of the pins of the plug;

FIG. 2 shows a plug pin according to the invention with a short cavity.

Detailed ways

According to FIG. 1 a , the plug pin, generally designated 1 , comprises a connection end 2 for connecting a power supply strand, not shown, and an extruded central area leading from the connection end 2 to a contact end 3 on the socket side. 4, wherein the central region 4 is hollow, as indicated by the cavity 4a, and the connecting end 2 is formed as a clamping end 2a.

The plug pins 1 are used in this example for a double-secured plug and are injected into a plug bridge base 5 made of plastic during use. The plug pins are made of a specially conductive material, preferably brass which can be used here. The availability of other metals, particularly stainless steel, has been thoroughly described and published.

A funnel-shaped extension 2b is provided on the connection end 2, which makes it easier to push in the power supply strands, for example from the direction indicated by the arrow 6, without the strands affecting the safety of the finished power plug . It should be pointed out that the expansion funnel 2 b can be placed in front of the introduction funnel made of plastic belonging to the plug bridge base 5 and/or only a plastic funnel can be used without expanding the connection terminal area. It is also preferred that the connection area is expanded in a funnel-like manner and preceded by an additional plastic introduction funnel. It should be noted that different configurations are known for the design of the front funnel and its configuration in the direction of the plug pin, and such known configurations can be used with the plug pin according to the invention. In particular, the plastic funnel at the front has been proven to be flat in the direction of the plug pin; the plastic funnel is conically constructed in the form of a double cone; A region with a protruding or cylindrical protruding to make it level.

In the cross-section in FIG. 1 b it can be seen that the inner diameter of the funnel region 2 b is significantly greater than the inner diameter of the cavity 4 a of the lower middle region 4 in FIG. 1 b. Below the introduction funnel 2b there is a clamping area 2a, which extends between the surface 5a of the contact end of the power cable strands of the plug bridge base plate 5a and the funnel-shaped opening of the introduction funnel 2b, so that the inserted strands can be Clamped without damaging or damaging the base body 5 . This is indicated by the double arrow 2d. Corresponding dimensioning of this region is easily accomplished by a person skilled in the art. It can be seen that the area in which the clamping tool is embedded during the manufacture of the power plug does not completely extend to the plug bridge base plate 5a, nor does it deform the introduction funnel. The preferred inner diameter can be seen, for example, in the second view from the top in FIG. 1 b. It can also be seen that enough wall material is retained by the crushing to allow secure clamping without breaking plug pins or the like. Likewise, the wall thickness is selected such that a tight, in particular gas-tight, at least PVC fluid-tight closure of the strands is possible.

In this example the contact end 3 is completely closed, which is possible here only because the shown plug pin is produced from a solid material, ie a round steel wire. When using cut-off tubes, further options are available for adequately closing the contact ends.

As shown in FIG. 1 a , when a solid material is used, the front, ie, socket-side contact end is not completely hollowed out, but instead has a region at the front where the solid material remains. This area is made of solid material and is dimensioned such that the tip cannot be damaged by galvanic erosion or other adverse effects forming arcs during an extraction attempt with full load. The thickness of the tip region which is not hollow-formed can vary depending on the geometry of the socket-plug pin pairs according to the national standards. A sufficiently large thickness of the front end as shown in Figure 1a not only helps to provide the material to keep the plug pins intact in the event of a large galvanic erosion, but also helps to form a solid enough tip that will enter the arc when the arc is formed. The thermal energy of the material is better dissipated.

The central region 4 is initially hollow and thin-walled in particular in the region between the contact ends 3 and the surface of the plug bridge base plate 5 which is directed toward the socket side during use of the power plug (see 5 b ). This is shown in FIG. 1 b by the lowermost cross-sectional view. It can be seen that the main part of the cross-section shown is hollow. So it can be seen intuitively that this saves a lot of weight and material compared to solid material. The wall thickness is selected in such a way that on the one hand the minimum cross-section required for the set current exists even in thin-walled regions, and on the other hand both the plug pin and the plug pin injected into the plug bridge pass through the downturn without any problems. Drum test and similar tests. As shown, the annular wall is slightly thinner in the hollow middle region than in the clamping region, but this is not necessary.

In the region of the plug bridge base 5 , the thickness of the plug pins increases, as shown in FIG. 1 b in the third cross-sectional view from the top and in FIG. 1 a . The effect of the thickening is to form a shoulder 4c which can be slightly inclined downwards, ie does not have to (but can) protrude perpendicularly to the other plug pin walls, which fixes the plug pin so that it cannot be pulled out of the plug bridge base plate 5. It has been shown that such thickening is not necessary. At the same time, its outer shape is selected not as a circle, but as a shape different from a circle and therefore can be toothed or zigzag or have a profile arranged along the circumference of the surface, which is at least partially arranged, for example, in the subregion 4d, In this case, the outline region 4 d does not have to be arranged in the middle of the thickness of the plug bridge substrate, but a plurality of corresponding subregions can also be arranged. It is only important that the finer contouring of the surface can bring about an increased resistance to twisting.

This structure was formed and processed as follows.

First, a solid piece of material is cut and provided with an extrusion die, in which the cut material is formed into the desired shape by means of a single extrusion step. The extrusion punch is then introduced into an extrusion die filled with the cut raw material and thus forms the plug pins. It should be noted that a multi-stage molding method with other extrusion molding steps can also be realized. Multistage forming processes can likewise be carried out by means of an extrusion process.

In a preferred variant, no subsequent thermal processing is used, but the further processing of the plug pins is carried out directly. For this purpose, the plug pins can be injected in a conventional manner into the plug bridge base plate, after which the resulting plug bridge is equipped with power strands. After connection to the power supply strands, the plug body can be formed by surrounding casting of PVC material. There is no risk of PVC material being squeezed into the cavity here, since the clamping of the empty central region is sufficient to ensure that the material is not squeezed in.

It has been found that clamping does not have to be carried out only in cavities. Instead, the switching can also be effected by clamping tabs or the like. Clamping of particularly good quality can likewise be achieved.

It has been found that it is not necessary to deform the plug pin hollowly up to the tip of the socket side. Instead, it is sufficient that the central region is hollow. This is shown in FIG. 2 , where at the height of the base plate on which the plug pins are fixed, there is still a solid material in the direction of insertion.

Claims (19)

1. a plug pin, have the zone line for the contact jaw guiding link that is connected with the power supply twisted wire and extrusion modling, from link to the socket contact side, it is characterized in that, link is designed to pinching end and zone line is designed to hollow.

2. plug pin as claimed in claim 1, is characterized in that, link is in the one side expansion of power supply twisted wire.

3. plug pin as claimed in claim 2, is characterized in that, link exists infundibulate or wing expansion.

4. plug pin as claimed in claim 2 or claim 3, is characterized in that, the standard of the expansion of link is to make it possible to be squeezed into deformation mechanism.

5. plug pin as claimed in claim 4, is characterized in that, described deformation mechanism is cone shape deformation mechanism.

6. plug pin as described in any one in claim 1-3, is characterized in that, plug pin is for the safety plug design size.

7. plug pin as claimed in claim 6, is characterized in that, described safety plug is the dual fail-safe plug according to European standard.

8. plug pin as described in any one in claim 1-3, is characterized in that, plug pin to have anti-distortion and/or prevents extracting protection in order to be fixed in plug bridge-unit of plastic.

9. plug pin as claimed in claim 8, is characterized in that, anti-distortion and/or anti-extract protection by roll extrusion, be pressed into or be cast into formation.

10. plug pin as described in any one in claim 1-3, is characterized in that, plug pin is made of the hollow member of extrusion modling.

11. plug pin as described in any one in claim 1-3 is characterized in that plug pin is made of solid material.

12. plug pin as described in any one in claim 1-3 is characterized in that, plug pin is with in order to form anti-distortion protection and/or anti-ly to extract the mold shaping method that protection adopted and make.

13. plug pin as described in any one in claim 1-3 is characterized in that, the weight of zone line is the external dimensions maximum 70% of the weight of identical solid member with it.

14. plug pin as described in any one in claim 1-3 is characterized in that, the weight of zone line is the external dimensions maximum 40% of the weight of identical solid member with it.

15. plug pin as described in any one in claim 1-3 is characterized in that the material of plug pin is brass or stainless steel.

16. a plug bridge has at least one plug pin as described in any one in aforementioned claim.

17. a power line has plug bridge as claimed in claim 16.

18. an electrical equipment has power line as claimed in claim 17.

19. one kind for the manufacture of the method as the described plug pin of any one in claim 1-15, it is characterized in that, adopt a kind of with hard instrument, with forward the extruding or backward the extruding method or adopt fluidstatic pressing method as the extrusion modling of the zone line of plug pin.

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