GB2338123A

GB2338123A - Mounting a plug contact on a plug body

Info

Publication number: GB2338123A
Application number: GB9906062A
Authority: GB
Inventors: Ng Yuk Hung
Original assignee: Helms Man Ind Co Ltd
Current assignee: Helms Man Ind Co Ltd
Priority date: 1998-03-21
Filing date: 1999-03-18
Publication date: 1999-12-08
Anticipated expiration: 2019-03-18
Also published as: GB9906062D0; DE19812501C1; AU2132499A; GB2338123B; AU740361B2

Abstract

A plug contact has an elongate conductive body 8, a contact tip 28 press-fitted thereon and an insulating sleeve 42. The plug contact is mounted with clearance in an aperture 9 in a conductive wall 2 of a plug body. A holding element 58, 65 press-fitted onto the elongate conductive body 8 bears on the inside of the wall 2 to retain the plug contact: the holding element 58, 65 and the contact tip 28 retain the body 8 in the aperture in the aperture with the sleeve being forced into contact with the outside of the wall.

Description

A PLUG DEVICE 2338123 The invention relates to a plug device comprising at

least one plug contact attached a housing wall of a plug housing, said contact having an electrically conductive longitudinal body extending through a lead through opening in the housing wall, said body having an inner longitudinal section extending away from the housing wall to an inner side of the plug housing and serving for electrical connection with at least one electrical lead, said body having an outer longitudinal section extending away from the housing wall to an outer side of the plug housing opposite to the inner side, said outer longitudinal section being provided on its outer end portion with a contact portion, said outer longitudinal section having, at least on its outer end port--',on, a contact face servina for the production of an electrical plug connection with a mating plug member, said contact face bearing externally against the housing by the intermediary of a first abutment face, a holding element being present press fitted on the inner longitudinal section of the longitudinal body, said holding element bearing on a second abutment 'Lace on the interior of the housing wall so that the plug contact is held on the housing wall by thrusting the two abutment faces against the housing wall from opposite sides.

A plug device of this type, which for instance may be employed for an electrical line plug for the electrical supply of an electrical or electronic appliance, is for instance disclosed in the German patent publication 1,024,602 B. It comprises a plug housing, which is generally manufactured of plastic material by injection molding, the individual plug contacts being made integrally and being able to be manufactured separately from the wall of the plug housing. In the course of assembly the respective plug contact is inserted through a lead through opening in the housing wall until its first abutment face, which is for instance in the form of a step, externally engages the housing wall, whereafter an annular holding element is thrust - 2 onto the inner longitudinal section until it engages a second abutment face on the inner side of the housing within. The fixing in place of the plug contact is accordingly based on the principle of thrusting the two abutment faces from opposite sides against the housing wall.

A similar design of a plug device is also shown in the German patent publication 1,490,757 B and the US patent 4,127,942.

As compared with other known designs as well, in the case of which the plug contacts are embedded and attached directly during injection molding of the housing wall, the above mentioned designs do have the advantage of simpler assembly, since there is no awkward operation of putting in place of the plug contacts in the injection mold employed from the production of the housing wall. However there is still the disadvantage that for the production of plug devices, which for instance must comply with d-.. llferen- standards for different countries, in each case completely different, separate plug contacts must be used. If it is a question of cylindrical plug contacts, there is moreover the danger of the plug contacts being bent during further manufacturing operation, something which leads to defects.

Accordingly it is one object of the present invention to provide a plug device of the type initially mentioned, which ensures simpler, more precise and more adaptable production.

In order to achieve this object there is the provision that the contact portion is constituted by a contact element which is separate with respect to the longitudinal body, said contact element having the configuration of a sleeve or cap and being pressed on the inner longitudinal section of the longitudinal body, it bearing against the housing wall by the intermediary of a spacing sleeve having the first abutment face and coaxially surrounding the longitudinal body, and furthermore the both the spacing sleeve and also the holding element consist of electrically insulating material.

This means that the contact portion possessing the contact face is constituted by a sleeve- or cap-like contact element, which is a part separate from the conductive longitudinal body and is fixed with a press fit on the conductive longitudinal body. There is thus the possibility of adaptation to different standards or for other reasons by simply changing the external shape of the contact element and connection with a standard pin-like longitudinal body. The latter may, if suitably designed, be obtained at a low price by cutting off from raw material in the form of continuous lengths, the danger of undesired deformation being considerably reduced. The design of the spacer sleeve and of the holding element using electrically conductive material leads to a further reduction in costs, more especially because the parts holding the electrical plug contact on the housing wall are electrically insulated from the housing wall. For safety reasons in the case of housing walls in contact in a load supporting manner with components carrying current there is often a requirement for particularly heat resistant material. Since there is now a possibility of producing the firm connection between the plug contact and the housing wall with electrically insulating elements therebetween, the housing wall may be manufactured of less high-quality and accordingly cheaper material, this generally reducing the costs of production.

Further advantageous developments of the invention are defined in the claims.

As a material for the spacer sleeve and/or the holding element a plastic is preferably employed.

It is further an advantage if centering means are provided on the outer side of the housing wall adjacent to the periphery of the lead through opening, such means being in engagement with the centering means of the spacer sleeve.

This measure means that the position of the spacer sleeve in relation to the lead through opening is set and defined with the result that assembly of the plug contacts of the housing wall is even further simplified.

The centering means may in this respect be constituted by a centering recess, into which the end section, having the first abutment face, of the spacer sleeve fits, which is shaped to be essentially complementary to the centering 4 - recess and which constitutes the mating centering means. Accordingly both the centering means and also the mating centering means are able to be manufactured in a particularly simple fashion.

Furthermore it is advantageous for the spacer sleeve setting the distance between the housing wall and the contact element to be seated on the longitudinal body free of a press fit. On assembly it is consequently sufficient to slip the spacer sleeve loosely onto the longitudinal body.

It is moreover advantageous for the longitudinal body to extend through the lead through opening in the housing wall free of a press fit so that it is unnecessary to adapt the cross section of the lead through opening exactly to the cross section of the longitudinal body. In this respect there is the possibility of making the lead through opening so large that there is a small clearance between the longitudinal body and the hearing wall. In consequence it is possible for departures in the cross section of the lead through opening owing to inaccuracies in manufacture to be compensated for in a better manner.

It is appropriate for a plurality of and more particularly two mutually parallel plua contacts to be provided, there being a single holding element for the internal longitudinal sections of the longitudinal bodies. It then suffices for the holding element to be pressed onto the inwardly extending longitudinal sections of the longitudinal bodies on attachment of the plug contacts in a single operation.

In the case of a further advantageous embodiment the longitudinal bodies and/or the contact elements are manufactured of copper or a copper alloy. It is in this manner that it is possible to ensure a high degree of conductivity of the longitudinal body or, respectively, of the contact element while keeping to low production costs.

In the following a working embodiment of the invention will be described with reference to the accompanying drawings.

Figure 1 shows a first embodiment of the invention of a plug device in an elevation, the one part being illustrated in a partially sectioned exploded view and the other in a sectional view.

Figure 2 shows the plug device of figure 1 in a transversely sectioned view on the section line II - II of figure 1.

Figure 3 shows a second embodiment of a plug device of the invention in a view like that of figure 2.

Figure 1 shows a first embodiment of the invention in the form of a plug device 1, which possesses at least one and for instance two parallel plug contacts 4 attached a wall 2 of a plug housing 3.

In the case of the plug device 1 it is a question for instance of a line plug, which serves for plugging into a conventional plug receptacle. The plug device 1 is normally connected by the intermediary of an electric cable, not illustrated in detail, with any desired electrical or electronic appliance so that such appliance is able to be connected with the power supply in the form of the plug receptacle. In the plug housing 3 it is possible for a regulator means to be arranged, at whose input the line voltage is present which comes from the plug contacts 4 and which supplies the power with the desired amperage and voltage.

It will be clear that dependent on the purpose of use it is also possible for more than two parallel plug contacts 4 to be provided. Furthermore, the configuration of the plug housing 3 depends more particularly of the application of the plug device 1 and is hence to be adapted in this respect. For instance there are different possible configurations of the geometry of line plugs for different countries, the working examples of the plug device 1 complying with the usual design for Germany, such plugs being more especially compatible for other countries in the European region.

The plug contacts 4 each comprise an electrically - 6 conductive longitudinal body 8, which extends through a lead through opening 9 provided in the housing wall 2. In this respect the longitudinal body 8 extends through the housing wall 2 free of any press fit with the result that it is not fixed in its axial direction 10. Although it is possible for there to be contact or a slight clamping effect between the housing wall 2 and the longitudinal body 8 adjacent to lead through opening 9, this is not in fact necessary. Quite on the contrary, it may be convenient to have a small radial distance between the longitudinal body 8 and the housing wall 2 adjacent to the lead through opening 9 so that inaccuracies in manufacture of the housing wall 2 as regards the lead through openings 9 may be compensated for on fitting of the plug contacts 4 to the housing wall 2.

The longitudinal body 8 of a respective plug contact 4 has an inner longitudinal section 14 extending away from the housing wall 2 to an inner side 13 of the plug housing 3. it serves for electrical connection with at least one lead, as for instance as a direct connection with the associated electrical appliance or a regulator means possibly accommodated in the plug housing 3 or able to be arranged in same.

On the outer side 15, opposite the inner side 13 of the plug housing 3, the longitudinal body 8 has an outer longitudinal section 16 extending away essentially at a right angle from the wall 2 and running in the axial direction 10, and which is adjoined by the inner longitudinal section 14 of the longitudinal body 8.

The free outer end portion 20, opposite to the housing wall 2, of the outer longitudinal section 16 is provided with an electrically conducting contact face 21, in the in the present case has a shape in the form of a complete loop around the longitudinal axis of the longitudinal body 8 in the peripheral direction 22 with the result that it corresponds to the peripheral surface of a cylinder.

As a modification of the embodiment of the invention it would be possible for the contact face 21 to have a surface section projecting in the axial direction 10, it being possible for the entire outer face 25 of the outer longitudinal section 16 to form the contact face.

The contact face 21 serves from the production of an electrical plug connection with a mating plug contact, not illustrated, which could for instance be constituted by a standard line power outlet. On plugging in the plug device into the line power outlet the contact face 21 of a respective plug contact 4 comes into engagement with a corresponding mating contact face with the result that at the same time the electrical plug connection will be produced.

In the part adjacent to the contact element 28 the cross section of the plug contact 4 is larger than the cross section of the axially adjoining portion of the longitudinal body 8. Thus the outer longitudinal section 16 is designed so that it is radially extended by the contact face 21.

As shown in figure 1 the contact face 21 is provided on a cap-like contact element 28, formed separately from the longitudinal body 8, such contact element 28 having a substantially cylindrical configuration. The contact element 28 comprises a blind press-on recess 29 extending in the axial direction 10, which is open toward the first axial side 30, associated with the longitudinal body 8, of the contact element 28. On this first axial side 30 there is as a result an annular flange 31 adjoining the press-on recess 29 annularly in the peripheral direction 22.

On the second axial side 34, opposite to the first axial side 30, of the contact element 28 same is in a closed form with the result that there is a generally cap-like configuration. As an alternative to this it would be possible for the contact element 28 also to be like a sleeve, the presson recess 29 being open toward the second axial side 34 of the contact element 28 as well.

The contact element 28 is pressed onto the outer longitudinal section 16 of the longitudinal body 8, it for example only surrounding the outer end portion 20 of the outer longitudinal section 16. On attachment of the contact element 28 by means of a press fit on the outer end portion 20 of the outer longitudinal section 16 of the electrically - 8 conductive longitudinal body 8 an electrically conductive connection will be obtained between the contact face 21 provided on the contact element 28 and the longitudinal body 8. Thus an electrical connection will be produced between the contact face 21 and the inner longitudinal section 14 of the longitudinal body 8.

The longitudinal element 8 possesses an essentially constant cross section, which for example is selected to be circular so that the longitudinal body 8 may be given the shape of a pin. It is only at its two axial end portions that the longitudinal body 8 may be provided with a chamfered edge 37 and 38. This provides for the possibility of manufacturing the longitudinal body 8 by simple cutting off from running lengths of stock as a raw material, complex working of the longitudinal body 8 being unnecessary.

Because the contact face 21 is provided on the contact element 28, it lis possible for it to be adapted to the respectively assigned purpose of use or, respectively, the associated mating contact face of the mating plug member without any complex machining operation being required on the longitudinal body 8. The contact element 28 as well can for example be produced by having a hole forming the press-on recess 29 in the terminal face into which a wire, cut off from a running length, or a rod, is inserted before it is cut to the required length. The running length may then be selected freely with a suitable cross section so that the contact elements 28 may be manufactured in a simple and cheap fashion with a different cross sections and accordingly different contact faces 21.

In order to provide for good electrical conductivity in the embodiment of the invention both the contact element 28 and also the longitudinal body 8 are manufactured of copper or a copper alloy. It is of course possible to use utilize any other electrically conductive material for the longitudinal body 8 and the contact element 28. There is also the possibility of providing these two components only partly with electrically conductive portions as long as there is a sufficient electrical connection between the contact face 21 and the associated inner longitudinal section 14 of the longitudinal body 8. In addition it would be possible for the longitudinal body and/or the contact element 28 to be coated with the suitable material, as for example for protection against corrosion or in order to lower contact resistance.

The contact element 28 has a first abutment face 41 externally in engagement with the housing wall 2 for support. The first abutment face 41 is provided on a spacer sleeve 42, which bears against the housing wall 2. In the example, the first abutment face 41 may be in engagement near the peripheral portion of the through lead opening 9 on the housing wall 2.

Alternatively to the preferred embodiment the contact element 28 could completely surround the outer longitudinal section 16 of the longitudinal body 8 in the axial direction 10 so that the annular face 31 might constitute the first abutment face 41.

As will appear from figure 1, the spacer sleeve 42 is arranged axially between the contact element 28 and the housing wall 2 of the plug housing 3. It possesses a tubular configuration and surrounds a part of the outer longitudinal section 16 of the longitudinal body 8 coaxially. In this respect the spacer sleeve 8 preferably rests on the longitudinal body 8 or, respectively, its outer longitudinal section 16 free of any press fit. During assembly of the plug device 1 it is then loosely slipped over the longitudinal body 8.

On the annular face 31 facing the spacer sleeve 42, of the contact element, which constitutes an abutment face 43, the spacer sleeve mating abuts at an abutment face 44, said face 44 surrounding the outer longitudinal section 16 of the longitudinal body 8 in an annular manner as well. At its end section 45, which is opposite to the mating abutment face 44, the spacer sleeve 42 possesses the first abutment face 41. Same is provided for example on the terminal face of the spacer sleeve 42 facing in the axial direction 10 and extending annularly and coaxially in relation to the longitudinal body 8.

The contact element 28 is provided with an outer axial section 48 of the spacer sleeve 42, whose cross section is less than that of the contact element 28 with the result that the same projects in a radial direction past the outer axial section 48. The outer axial section 48 is adjoined by the end section 45 of the spacer sleeve 42, whose cross section is larger than that of the outer axial section 48 and has approximately the same cross section as the contact element 28.

In the illustrated working embodiment the spacer sleeve 42 is electrically insulated from the longitudinal body 8 and the contact element 28. In the course of insertion of the plug device 1 in the plug mating member or socket, which for instance is constituted by a line power outlet or receptacle, the user will be provided with a guard to prevent getting a shock on touching 1-1ve conductors at the spacer sleeve 48, lif the contact faces 21 are already in electrical contact with the mating contact faces of the mating part of the plug. This measure is more particularly to be recommended in the case of plug housings 3 with a flat form, as is illustrated in figure 2. Such plug housings 3 may be termed flat plugs as well.

In the illustrated working embodiment the spacer sleeve 42 is manufactured of insulating material and is preferably made of plastic.

In the circumferential part of the lead through opening 9 centering means 51 are located externally on the housing wall 2, such means being in engagement with mating centering means 52 provided on the spacer sleeve 42. The result of this is that in relation to the lead through opening 9 the spacer sleeve 49 adopts a predetermined, desired alignment. More particularly the central opening 53 extending in the interior of the spacer sleeve 48 in the axial direction is aligned with the lead through opening 9.

In the case of the preferred embodiment the centering means are constituted by a centering recess 54 formed externally inside the housing wall 2, the cross section of 11 such recess 54 being made complementary to the outer shape of the end section 45 of the spacer sleeve 42, this end section 45 of the spacer sleeve 42 forming the mating centering means 52.

The centering recess 54 extends coaxially to the lead through opening 9 and is in cross section substantially circular.

On the inner longitudinal section 14 of the longitudinal body 8, which is associated with the inner side 13 of the plug housing 3, a holding element 58 is press fitted, which for at least a part of its length surrounds the outer longitudinal section 14 in an annular or sleeve-like manner.

It hence has a passage opening 59 extending in the axial direction 10, in which opening the portion, surrounded by the holding element 58, of the inner longitudinal section 14 of the longitudinal body 8 is arranged with a press fit.

Furthermore the holding element 58 has a second abutment face 60, at which it rests against the housing wall 2 on the inner side 13 of the plug housing 3. In the illustrated working embodiment the second abutment face 60 is thrust from the inside against the housing wall 2 at least in the peripheral portion of the lead through opening 9.

In the case of the embodiment of the plug device 1 in the form of a line plug the device has two mutually parallel plug contacts 4, which are arranged at a distance apart on the housing wall 2 of the plug housing 3.

The inner longitudinal sections 14 of the longitudinal bodies 8 of the plug contacts 4 have a common single holding element 58 so that same has two passage openings 59, which are respectively fixed in place by a press fit on the associated inner longitudinal section 14 of the longitudinal body 8.

Moreover the holding element 58 possesses an abutment plate 62, whose one plate face constitutes the second abutment face 60, at which the holding element 58 presses from the inside against the housing wall 2. The abutment plate 62 respectively comprises a first section 63 of the respective passage opening 59 and extends linearly between the portions, having the passage openings 59, of the holding element 58. The abutment plate 62 is formed with its two ends rounded off which are placed adjacent to the passage channels 59, the rounded parts extending generally coaxially to the respectively associated passage opening 59.

The passage openings 59 have a second section 64 thereof, which is aligned with the first section 63, extending in a respectively collar- like holding portion 65 which, on the rear face 66 (opposite to the second abutment face) extends away from the abutment plate 62. The holding portion 65 coaxially surrounds the respectively associated inner longitudinal section of the longitudinal body 8 in its immediate peripheral portion and has a generally cylinderlike shame, it having the second section 64 of the passage opening 59 extending through it in the axial direction 10. Accordingly there is a transverse supporting action for the longitudinal body over a relatively great length.

It is convenient for the holding element 58 to have an abutment face 41, which is insulated from the components of the plug contact 4 conducting current during operation, abutting the housing wall 2. It is an advantage for it to be manufactured of plastic and more especially nylon.

By thrusting the two abutment face 41 and 60 from the outside and, respectively, from the inside, against the housing wall 2 of the plug housing 3 the respective plug contact 4 will be held on the plug housing 3 and, respectively, on the housing wall 2. Because both abutment faces 41 and 60 are insulated from the components for carrying current of the plug contact 4, the load bearing contact between the housing wall and the plug contact is via parts which do not carry current, this making it possible for the housing wall to be manufactured of a plastic material which is of a lower quality and consequently lower in price.

The end 69, which is at the inner side 13 of the plug housing 3, of the inner longitudinal section 14 of a respective longitudinal body 8 projects, on the side opposite the housing wall 2, of the holding element 58 out of the respective passage opening 59 a short distance so that such end 69 is accessible in order for example to electrically join the initially mentioned electrical leads with the inner longitudinal section 14 of the longitudinal body 8.

In order to improve the press f it between the contact element 28 and the longitudinal body 8 or, respectively, the holding element 58 and the longitudinal body 8 it is possible for its outer face 25 to have grooves or roughness in some other suitable form. In the working example the outer face 25 has several helical or spiral grooves 72, which, which on the surface 25 constitute rhombic segments 73.

Figure 3 shows a second possible form of construction of the plug housing 3 in a view similar to that of figure 2. The housing is here generally cylindrically shaped, it being designed to be complementary to the female portion of a power outlet, customarily employed in buildings, for a 220 volt line supply. In this construction two ground contacts 75 are externally provided on opposite outer sides of the housing wall 2, such ground contact being indicated in chained lines in figure 3. In the plugged in condition of the plug device 1 such contacts cooperate with mating contacts in such a plug receptacle, an electrical connection being produced between the ground contacts 75 and the mating contacts. Such mating contacts are connected with ground with the result that metal parts of a housing of an electrical appliance provided with the plug device 1 may be connected with ground for protection of the user by means of a connection with the ground contacts 75.

An advantageous method for the application of a plug contact 4 to the housing wall 2 will be described in the following.

Firstly the contact element 28 is pressed onto the one end of the longitudinal body 8. Then the spacer sleeve 42 is slipped over the longitudinal body 8, whereafter the longitudinal body 8 is inserted in the lead through opening 9 with its end, which is opposite to the contact element 28, first from the outer side 15 of the plug housing 3. When this is done the end section 45 of the spacer sleeve 42 fits into the associated centering recess 54 and the first - 14 abutment face 41, provided on this end section 45 of the spacer sleeve 42, will rest on the outside of the housing wall 2 of the plug housing 3. Furthermore the abutment face 43 of the contact element 28 and the mating abutment face 44 of the spacer sleeve 42 come into engagement with the result that the spacer sleeve sets the axial distance of the contact element 28 from the outer face of the housing wall 2 automatically.

If the plug device 1 has several plug contacts 4 the above described steps are performed for each of the plug contacts 4.

on the inner longitudinal sections 14, which project into the interior of the plug housing 3, the holding element 58 is then pressed so that the second abutment face 60 is thrust from the inside against the housing wall 2. There is, as it were, a sort of clamping action on the housing wall 2 between the two abutment faces 41 and 60 so that the plug contacts 4 are securely held against the housing wall 2.

The application of the plug contacts 4 is accordingly performed using an extremely simple assembly method which can be carried out by machine without extensive hand labor. The costs of production of a plug device 1 may consequently be kept extremely low.

is

Claims

1. A plug device comprising at least one plug contact attached to a housing wall of a plug housing, said contact having an electrically conductive longitudinal body extending through a lead through opening in the housing wall, said body having an inner longitudinal section extending away from the housing wall to an inner side of the plug housing and serving for electrical connection with at least one electrical lead, said body having an outer longitudinal section extending away from the housing wall to an outer side of the plug housing opposite to the inner side, said outer longitudinal section being provided on its outer end portion with a contact portion, said outer longitudinal section having, at least on its outer end portion, a contact face serving for the production of an electrical plug connection with a mating plug member, said contact face bearing externally against the housing by the intermediary of a first abutment face, a holding element being present press fitted on the inner longitudinal section of the longitudinal body, said holding element bearing on a second abutment face on the interior of the housing wall so that the plug contact is held on the housing wall by thrusting the two abutment faces against the housing wall from opposite sides, wherein the contact portion is constituted by a contact element which is separate with respect to the longitudinal body, said contact element having the configuration of a sleeve or cap and being pressed on the outer longitudinal section of the longitudinal body, it bearing against the housing wall by the intermediary of a spacer sleeve having the first abutment face and coaxially surrounding the longitudinal body, and furthermore both the spacer sleeve and also the holding element consist of electrically insulating material.

2. A plug device as claimed in claim 1, wherein the spacer sleeve and/or the holding element are manufactured of plastic material.

3. A plug device as claimed in claim 1 or in claim 2, wherein the two abutment faces in the peripheral portion of the lead through opening rest 16 against the housing wall.

4. A plug device as claimed in any of claims 1 through 3, wherein on the outer side of the housing wall of the plug housing in the peripheral portion of the lead through opening centering means are provided which are in engagement with centering means on the spacer sleeve.

5. A plug device as claimed in claim 4, wherein the centering means are constituted by a centering recess, into which the end section, having the first abutment face, of the spacer sleeve fits, which is essentially complementary to the centering recess and constitutes the centering means.

6. A plug device as claimed in any of claims 1 through 5, wherein the spacer sleeve is seated on the longitudinal body in a manner free of a press fit

7. A plug device as claimed in any of claims 1 through 6, wherein the longitudinal body extends through the lead through opening in the housing wall without any press fit.

8. A plug device as claimed in any of claims 1 through 7, wherein the holding element surrounds the inner longitudinal section of the longitudinal body for at least a part of its length in the manner of a ring or sleeve.

9. A plug device as claimed in any of claims 1 through 8, wherein several and more especially two mutually parallel plug contacts are provided, the inner longitudinal sections of the longitudinal bodies sharing a double holding element.

10. A plug device as claimed in claim 9, wherein the holding element has a more particularly elongated abutment plate, on which the second abutment face is provided.

A plug device as claimed in claim 10, wherein in the peripheral portion 17 of each inner longitudinal section the holding element possesses a collarlike holding portion extending away from the side, which is opposite to the second abutment face.

12. A plug device as claimed in any of claims 1 through 11, wherein the longitudinal body and/or the contact element are manufactured of copper or an alloy thereof.

13. A plug device substantially as described hereinbefore with reference to and as illustrated in figures 1 and 2 of the accompanying drawings.

14. A plug device substantially as described hereinbefore with reference to and as illustrated in figure 3 of the accompanying drawings.

15. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.