GB2096843A

GB2096843A - Connector element structure having a plurality of contacts for electrically connecting trailers or the like.

Info

Publication number: GB2096843A
Application number: GB8209807A
Authority: GB
Original assignee: Menbers SpA
Current assignee: Menbers SpA
Priority date: 1981-04-07
Filing date: 1982-04-02
Publication date: 1982-10-20
Also published as: DE3212848C2; IT8120975A0; AT383700B; ES272674Y; FR2503466A1; IT1137663B; FR2503466B1; ES272674U; NL8201338A; ATA135282A; GB2096843B; DE3212848A1

Abstract

A socket, particularly for a vehicle trailer comprises a casing member (2) and a contact carrier member (3) which are connected by mutual engagement of integral raised elements on the inside of the casing and outside of the contact carrier. The contact carrier member has contacts removably located in axial bores and is formed of thermoplastic material. The socket is cheap to manufacture. <IMAGE>

Description

SPECIFICATION Connector element structure having a plurality of contacts for electrically connecting trailers or the like This invention relates to a connector element structure or socket having a plurality of contacts for making an electrical connection between a motor vehicle and a trailer, for example a caravan or box trailer. As is known, the means for making an electrical connection between a motor vehicle and a trailer comprise a socket which is fitted to the motor vehicle and into which is inserted a plug which is connected to the trailer, the connection having a plurality of contacts which are disposed in a position and which are of a configuration which are standardised under international standards.

The known sockets are generally formed by an external casing of cap-like shape, which carries therein a contact carrier element and which is adapted to be associated, for example by means of screws, with the rear part of the towing vehicle.

In particular, the contact carrier element which is generally made of plastics material must be such that it can be firmly fixed in the cap-like body and at the same time be removable when that is necessary, in order, for example, to re-attach any conductors which have become disconnected.

A disadvantage which is found with the sockets of known type is that the operation of connecting the contacts, of male or female type, gives rise to considerable difficulty in the construction phase, requiring a considerable amount of labour and in many cases allowing the possibility, even if slight, of movement at the contacts, with the possibility in the worst case of damaging the electrical connection of the cables themselves.

For example, German Gebrauchsmuster 78 12 822 illustrates a socket having a plurality of contacts, a so-called "multipolar" socket, of the above-mentioned type, in which the contactcarrier insert is made in two parts which can be mutually engaged by pressure and which has a plurality of axial holes for receiving the male or female electrical connecting elements. The connection between the contact carrier element and the external cap-like casing is effected by engagement of respective recesses and projections and, once the contact carrier element has been engaged in the cap by using particular pressing tools, it can be disengaged only by the fresh application of pressure and using further tools.

The two-part construction of the contact carrier insert is obviously a disadvantage of the socket of the above-mentioned German specification, insofar as not only must the two parts be produced in two separate phases but in addition they require a further assembly phase which contributes to increasing the costs of the finished socket. In addition, in that known socket, as stated above, it is not possible easily to disengage the contact carrier insert from the cap-like body and moreover access to the contact members for any re-connection of the conductors which may be required is rather difficult. Finally, by virtue of its particular internal configuration, having projecting portions with recesses and ribs, the cap-like body cannot be constructed of metal material such as aluminium, which limits the field of application of the socket unless complicated assemblies of parts are added.

According to the present invention there is provided a multi-contact electrical connector socket comprising a casing body, a contact carrier element which is arranged to be removably received in the casing body, and a plurality of contact elements each removably located in an axial hole in the contact carrier element, wherein the carrier contact element is a single substantially' cylindrical element formed of a thermoplastic material and having a plurality of tooth elements formed integrally on its outside periphery, and the casing body has a multiplicity of further tooth elements integrally formed internally of the body, the tooth elements enabling axial insertion of the contact carrier element into the casing body and subsequent rotation of the contact carrier element to engage that element in the casing body.

The socket of the invention is particularly valuable as a socket on a vehicle for receiving a plug which is attached to a caravan or trailer.

Because of its mode of construction, the contact carrier element can be easily and rapidly fitted in a durable manner into a cap-like casing body and at the same time can just a easily and rapidly be removed, without the use of particular tools. In addition, electrical contacts of male or female type can be easily and firmly associated with the contact carrier insert by means of a single operation, thus eliminating any possibility of translation or movement of the contacts, and so improving the electrical connection.

One advantage of the invention is that all the elements for engagement between the contact carrier insert and the cap-like casing body are integral either with the insert or with the casing body and can thus be produced automatically during the operation of stamping or moulding the insert and the casing body respectively.

The casing body, which may carry a spring loaded dust cover of known type, may be made either of a plastics material or of a metal such as an aluminium alloy.

The electrical connector socket of the present invention can thus be easily produced from materials that are commonly commercially available; it does not require expensive or complicated equipment for producing it and so can be made highly competitive from a purely economic point of view.

Further features and advantages of the socket or electrical connector structure according to the invention will be more clearly apparent from the following particularised description of an embodiment thereof, which is illustrated by way of example in the accompanying drawings, in which: Figure 1 is a view from below of a socket according to the invention, the contact carrier element and a cap-like casing body being in their assembled condition, Figure 2 is a view in section taken along line Il-Il in Figure 1, Figure 3 shows a view from above of the contact carrier element, Figure 4 is a view from below of the contact carrier element, Figure 5 is a view in cross-section of the contact carrier element shown in Figures 3 and 4.

Figure 6 is a partly sectional view of the contact carrier element shown in Figures 3 to 5, Figure 7 is a view from below of the cap-like casing body, Figure 8 is a view in section taken along line VIlI-VIlI in Figure 1, Figure 9 is a front view of the cap-like casing body with an associated cover, and Figure loins a view from above of the casing body and cover shown in Figure 9.

Referring now to Figures 1 and 2, shown therein as a plan view and a view in section taken along line il--II, is a socket according to the invention, which is generally indicated by reference numeral 1.

It should be noted that the expression "socket" used in this description and claims indicates a connector element which is not associated with the electrical cable, that is to say, a connnector element which is provided to be connected to a fixed structure, such as the rear part of a towing vehicle. Obviously, the concept of the present invention can be applied to a structure, having electrical cables associated therewith, in which the contact carrier element and the protective casing are produced and coupled in accordance with the teachings of the invention.

The socket 1 comprises an external cap-like casing 2 which is made for example of a suitable thermo-plastic material such as polypropylene, or a metal material such as for example aluminium.

Fitted removably with the cap-like casing 2 is a contact carrier element 3 of substantially cylindrical configuration and produced by moulding a thermoplastic material such as polypropylene.

Referring now to Figures 3 to 6, the contact carrier element 3 is illustrated in greater detail therein.

As is known, the contact carrier element 3 comprises a plurality of axial holes 4 which extend axially along the cylindrical body of the element 3 and which are separated from each other by divider walls of thermoplastic material. In particular, each axial hole 4 has an upper collar portion 5 and is laterally open by way of a circumferential space 6 which terminates below the open collar portion 5 with sharp edges.

Advantageously, two small retaining portions 7, the purpose of which is to retain the electrical contact elements in the holes 4, are formed integrally adjacent the upper edge within each hole 4.

As is known, there are seven holes 4 in this embodiment, six holes being disposed in the form of a hexagon while the seventh hole is disposed centrally and is at a higher level than the plane of the upper mouth of the holes 6.

In accordance with the invention, provided on the outside periphery of the body of the element 3 is a grooved configuration, having radial side surfaces and formed by a plurality of upper projecting tooth elements 8 and a corresponding plurality of lower projecting tooth elements 9, each lower tooth element 9 being interposed between two upper tooth elements 8.Of the tooth elements 8, one which is indicated by reference 8' is of larger dimensions while another tooth element which is indicated by reference numeral 8" is provided, formed integrally therewith, with a stop projection 10 having a protruberance 1 Oa which, once the insert 3 has been coupled into the cap-like casing 2, can provide a gripping portion so that the insert 3 can be easily removed from the casing 2 when that is desired, for example for re-connecting any electrical conductor wires which may have become disconnected.

Obviously, the tooth elements 8 and 9 and the projection 10 are integral, as already stated, with the body 3, being formed during the operation of moulding the body.

Figure 5 shows a plug contact element 11 inserted into a corresponding hole 4. The plug contact element 11 has a lower shank portion and an upper head portion 12 of increased diameter.

The plug contact element is made of an electrically conducting material such as copper alloy. A screw 13 for clamping the respective conductor wire is threadedly engaged in the enlarged diameter portion 1 2.

As required by international standards, a plurality of male or female elements will be provided in the finished socket, with one element 11 for each hole 4. The plug contact element which is to be disposed in the central hole 4 is longer than the others to cause the head thereof with its screw to project.

Some holes 4 receive female contact elements, as shown at 1 a in Figure 2.

It should be noted that each hole 4 has a lower portion of increased diameter, to contain the female contact or to permit a plug contact element 11 to mate with a respective female contact which will be inserted from below, as shown in the drawing.

The sets of tooth elements 8 and 9 are spaced apart in the axial direction and there are five thereof in the illustrated embodiment, that is to say, one tooth less than the holes 4, at the perimeter of the arrangement. In this way, as will be clearly seen hereinafter, the contact carrier insert element will necessarily have to be inserted into the cap-like element 2, in a predetermined position.In order to make the coupling between the two components, with an axial rotational movement, provided integrally in the cap-like casing 2 is a corresponding plurality of teeth 1 4, the thickness of which is equal to the spacing between the teeth 8 and 9 of the contact carrier element 3, thus forming a series of recesses 14' into which pass the teeth 9 of the contact carrier element 3, while the teeth 8 thereof, being of larger diameter, bear against the circumferential edge portion 1 5 which is at the base of the teeth 1 4. One of the recesses 14" is enlarged while the adjacent tooth 14 is extended by a rib portion 1 spa to ensure that the two components 3 and 2 are assembled in a predetermined position (see Figures 7 and 8).The cap-like casing 2 has the above-mentioned rib portion 1 5a for positioning of the "plug" connector element which can be plugged into the assembled socket 1. Finally, shown in Figures 9 and 10 is the socket as viewed from the outside, a cover element 1 9 being provided, which can be pivotally fitted to the cap like casing 2 for protecting the electrical contacts.

The socket in accordance with the invention is assembled in the following manner: The electrical contact elements, being plug contact elements or female elements, are all inserted at the same time, by applying pressure, and by means of a suitable tool (not shown) from the smaller-diameter part 5 of the holes 4, making use of the resiliency of the thermoplastic material and the tapered entry at 5a.

More specifically, after the electrical contact .elements have been partially introduced from above the insert 3, the upper portions or enlargeddiameter head portions 12 thereof are pushed into the holes, causing the upper portions of the holes 4 to "expand". In this way, the head portions 1 2 of the contact elements will be forcibly introduced into the holes and the upper edge of each said head portion will bear against the step or collar 5, whereby the contact element will be unable to move in the opposite direction. In addition, the projections 7 will apply to each contact element a direct force eccentrically towards the solid part or wall of each hole 4, whereby each contact element will be firmly retained in the respective hole 4.In addition, by virtue of the provision of the sharp angles or corners at the upper edges of the holes 4, there will not be any opportunity for each contact element to escape axially.

In particular, the contact elements are inserted simultaneously into the holes 4 with the screws 1 3 already screwed thereinto. The screws 1 3 will be received in the openings 6 whereby the contact elements can be connected to the conductor wires in an extremely simple manner. For the purposes of fitting the contact carrier insert 3 within the cap like element 2, the insert 3 will be introduced from below the cap-like element 2 and then rotated by one step so as to move the free end of the projection 10 against a corresponding stop element or projection 1 7 formed on the inside of the casing 2 (see Figure 7).In this way, each upper tooth of the insert 3 will be disposed at the top between two adjacent teeth 1 4 of the cap-like casing 2, while each lower tooth 9 will be disposed below a respective tooth 1 4 of the element 2.

In this way the insert 3 will be locked in the cap-like casing 2 and the insert, besides not being able to move axially by virtue of the interarrangement of the corresponding teeth, will not even be able to rotate, by virtue of the provision of the projection 10 bearing against the internal projection 1 7 formed in the cap-like casing.

For the sake of completeness, finally, it should be noted that weakened regions 1 8 have also been formed in the wall of the cap-like casing 2 and can be removed by breaking them off in the event that the electrical conductors are to be taken out of the assembly through the wall of the cap-like casing.

It can be seen clearly from the foregoing description how the invention provides an electrical connector socket which is extremely simple to assemble and in which the contact carrier element is firmly retained in the cap-like casing, and can move neither axially, by virtue of the engagement of the teeth 8, 9 and 14, nor with a rotary movement, by virtue of the projection 10 being bearing against the projection 17. In addition, the contact elements in each hole 4 are also firmly retained, and cannot move axially either upwardly, by virtue of the collar portions 5, or downwardiy by virtue of the heads of the screws 1 3 being supported in the recesses 6, and cannot even perform very small axial movements, by virtue of the projections 7. At the same time, the insert element 3 can be easily removed, if desired.

In addition, the socket of the invention may have an external cap-like member either of plastics material or of metal material and in addition is of very low cost.

In practice, the materials used as well as the dimensions and shapes involved may be varied in accordance with requirements.

In addition, the contact between the conductors and the plug contact members 11-11 a, rather than being produced by means of a hole and clamping screw as illustrated, may also be made with known types of plate members and connecting means, with the plate members being soldered or welded to the ends of the respective plug contact member or female contact, from the larger-diameter part already described above.

In this case, the recess 6 which permits a certain resiliency in the collar portion 5 may be shortened to contain the above-mentioned contact plate member which in this way locks the plug contact member in regard to rotary movement.

It will be apparent that many variations of design nature, expecially in regard to the dimensions and the number of teeth and recesses for the coupling arrangement and the like may be made without thereby departing from the scope of the present invention.

Claims

1. A multi-contact electrical connector socket, comprising a casing body, a contact carrier element which is arranged to be removably received in the body casing, and a plurality of contact elements each removably located in an axial hole in the contact carrier element, wherein the contact carrier element is a single substantially cylindrical element formed of a thermoplastic material and having a plurality of tooth elements formed integrally on its outside periphery, and the body has a multiplicity of further tooth elements integrally formed internally of the body, the tooth elements enabling axial insertion of the contact carrier element into the casing body, and subsequent rotation of the contact carrier element to engage that element in the casing body.

2. An electrical connector socket according to claim 1 wherein each axial hole in the contact carrier element has a thickened wall portion at an upper mouth opening thereof and an enlarged diameter at a lower aperture thereof, a lateral aperture through which a clamping screw forming part of a contact element protrudes being formed adjacent the upper mouth opening.

3. An electrical socket according to claim 2 wherein each axial hole in the contact carrier insert is provided, just within the mouth opening, with a shoulder step capable of preventing upward axial translational movement of the contact element, the step extending circumferentially as far as the vicinity of the lateral aperture.

4. An electrical connector socket according to claim 3 wherein each axial hole in the contact carrier insert is provided, at each end of the step, with a respective projection acting to push each contact element eccentrically and thereby to prevent axial sliding movement of the contact element when without a screw.

5. An electrical connector socket according to any one of claims 1 to 4 wherein the contact carrier insert bears two sets of tooth elements in parallel spaced apart planes about its circumference, each tooth of one set lying angularly between two teeth elements of the other set.

6. An electrical connector socket according to claim 5 wherein the angular extent of one tooth of one of the sets of teeth is greater than that of the other teeth in that set.

7. An electrical connector socket according to claim 5 or 6 wherein the tooth elements of one set project radially of the substantially cylindrical element more than the tooth elements of the other set.

8. An electrical connector socket according to any one of the preceding claims wherein one of the the tooth elements carries a resilient curved stop projection capable of engaging with its free end against a stop projection formed on the inside of the casing body thereby substantially to prevent rotary movement of the contact carrier element in the casing body.

9. An electrical connector socket according to claim 8 wherein, adjacent its free end, the resilient curved stop projection carries a gripping pin portion for facilitating removing the contact carrier insert from the casing body.

10. An electrical connector socket having a plurality of contacts and substantially as hereinbefore described with reference to the accompanying drawings.