IE41794B1

IE41794B1 - Electrical contact element with stripless cable connection device

Info

Publication number: IE41794B1
Application number: IE200175A
Authority: IE
Original assignee: Itt
Priority date: 1974-09-13
Filing date: 1975-09-12
Publication date: 1980-03-26
Also published as: JPS5155983A; IE41794L; GB1519014A; IT1042449B; FR2285000A1; DE7525722U; FR2285000B1; DE2536184A1

Abstract

1519014 Terminals; two part connectors ITT INDUSTRIES Inc 12 Sept 1975 [13 Sept 1974] 37591/75 Heading H2E An electrical contact element has a cable connecting part 1 comprising a trough having an upstanding forked member 13. An unstripped cable for connection to the element is pressed into the opening between the tines 14, 15 of the fork so that the insulation is pierced and the core of the conductor is engaged by them. A cable grip comprises inwardly projecting tongues 7, 8, 9 formed from the side walls of the trough or alternatively a fork, similar to the fork 13 but with a larger opening so that the insulation is not pierced but gripped. A tongue 10 and shoulders 5, 6 serve a retention means for holding the element in an insulating block.

Description

The present invention relates to an electrical contact element for connection to unstripped cable.

For the connection of cables to contact elements, soldering and crimping operations or screws are commonly used. All these means usually necessitate the prior stripping of the cable to be connected and sometimes the operation of particularly complex apparatus. The cost of such cable connections may not be negligible when a large number of connections have to be made.

Attempts have been made to reduce the cost of making connect!ons,for example, by inserting a cable between lips, the edges of which cut the cable insulating sheath and contact its metallic core as the cable is inserted between them. However, the parts which contact the metallic core i.e. in this case, the cutting lips - are subject to strains when the cable is introduced into them, which'reduces the reliability of any electrical connection.

According to the present invention, there is provided an electrical contact element for connection to unstripped cable including a trough shaped part, a forked member cut from the base of said part so as to be upstanding in the trough and abutting the walls thereof, the arms of the forked member being so shaped that upon the insertion of suitable unstripped cable between the arms of the fork, the arms, which are thereby pressed into closer contact with respective walls of the trough, bite through the unstripped insulation into the conductor core of the cable, means being provided to restrain the cable against withdrawal from the element as a result of a force tending to pull the cable and the element apart.

The invention will now be more particularly described with reference to the accompanying drawings illustrating embodiments thereof in which: Figure 1 is a perspective view of a contact element according to a first embodiment, Figure 2 is a perspective view of a cohtact element such as that of Figure 1 after the positioning of a cable to be connected.

Figure 3 is a perspective view of an alternative embodiment to the - 2 contact element of Figure 1.

Figure 4 is a perspective view of the contact element of Figure 3, after the positioning of the cable to be connected.

Referring to the drawings, Figure 1 shows a contact element for plugging into a socket, having a first part 1, which is arranged to allow a cable connection to be made to it without stripping the cable of its insulating sheath, and a second part 2, which provides the male contact plug element. Obviously the part 2 could be of any other well known shape used for contact elements (i.e. not plug-and-socket elements only).

During the manufacture of the contact element, the part 1 is folded so that it forms a trough having a U-shaped cross section. The height of the walls 3 and 4 of the trough is not the same throughout its length.

Shoulders 5 and 6 are formed which act as a stop for the contact element when it is inserted, as it may be, in a connector insulating piece.

Tongues 7,8 and 9 are cut out of the walls 3 and 4 and their free ends are folded inwards. Another tongue 10 is provided in(the bottom of the trough which ensures that the contact element is held in position after its insertion in a connector insulating piece. For this purpose, the tongue 10 is folded outwards, in well-known manner. It may be sprung inwards when the contact element is moved in the direction of the arrow 11 and inserted in an insulating piece. After insertion in the insulating piece, the tongue 10 springs outwardly to abut a shoulder on the connector insulating piece and lock the contact element in the insulating piece so that it cannot be moved with respect to the insulating piece in the direction of arrow 12.

It is to be noted that the contact element locking tongue 10 is cut out of the bottom of the trough along the walls 3 and 4. The cut material is not removed but is bent up to form a forked lug 13. The latter, which has an important function, is thus obtained simultaneously with the tongue 10 as a result of a single cutting process. The lug 13 has a generally U-shaped internal cut-out corresponding to the shape of the tongue 10. This U-shaped cut-out is wider towards the top of the trough. It will be noted that the lug 13 has arms 14 and 15 which abut the internal faces of walls 3 and 4. - 3 41794 Referring to Figure 2 which shows the contact element of Figure 1 after a cable 16 has been introduced into the U-shaped trough, a part of the wall 4 has been cut-away in order to enable the drawing to be understood more clearly. The cable 16 is inserted, in the direction of the arrow 17 between the arms 14 and 15. The upper more widely spaced parts of the arms 14 and guide the cable past sloping shoulders towards flanks 18 and 19 which, being closer together, progressively engage the cable as it is inserted into the lower part of the lug 13. As the distance between the flanks 18 and 19 is slightly less than the diameter of the metal core of the cable, the flanks 18 and 19 bite into the core metal and ensure a good metallic connection between the lug 13 and the cable core.

An advantage offered by the device is that, when the cable 16 is inserted into the trough 1, the force exerted upon the arms 14 and 15 tending to urge them away from one another is resisted since they each abut one Of the side walls 3 and 4. The arms 14 and 15 are thus very effective in establishing contact with the metal core of the cable.

It will be also noted that since the tongues 7,8 and 9 are-folded inwardly they bite into the cable insulating sheath with their sharp edges when the cable 16 is inserted without touching its metallic core. They thus ensure that the cable is retained in position and make its withdrawal difficult by biting more and more deeply into it if it is pulled in the direction of the arrow 20.

Referring to Figure 3, in which the contact element shown is an alternative to that of Figures 1 and 2, it can be seen that this contact element 21 includes a lug 22 which is identical to the lug 13 of the previous figures, both as far as its manufacture and its function with respect to the Cable are concerned. However, the contact element 21 has another lug 23. This lug 23 has a U-shaped internal cut-out, similar to that of the lug 22 and it is folded at right angles to the bottom of the contact element 21. The 3θ lugs 22 and 23 are thus arranged in planes parallel to each other, their respective arms abutting side walls 24 and 25. The rear ends 26 and 27 - 4 41794 of these walls are folded inwardly and there are no tongues such as 7,8 or 9 of Figures 1 and 2. The upper part of the U-shaped opening situated between the upper parts of the arms of the lug 23 has the same width as the corresponding part of the opening of the lug 13 of Figures 1 and 2, whereas the width of the lower part of the opening located almost at the bottom of the fork formed by the arms of the lug 23 is slightly smaller than the external diameter of the cable insulating sheath but greater than the diameter of its metallic core.

Such an arrangement enables a cable 28 to be inserted in the same way as that described with reference to Figure 2. Figure 4 illustrates this fact. As already described with reference to Figure 2, the lower part of the lug 22 which is identical to lug 13 cuts the insulating sheath of the cable 28 and bites into its metallic core. However, it is to be noted that the lug 23 only bites the insulating cable sheath without touching the metallic core of the cable and thus ensures that the cable is held in position, which function was previously assigned to the tongues 7,8 and 9 in Figure 2. Indeed, if the cable 28 is subject to traction efforts in the direction of an arrow 29, these efforts act upon both lugs 22 and 23, but as the lug 23 abuts the folded extremities 26 and 27 of the lateral walls, the traction efforts are absorbed by these extremities 26 and 27 and the lugs 22 and 23 remain vertical between the walls 24 and 25.

It will be understood that the preceding description has only been given by way of example and that numerous alternatives are possible without departing from the scope of the invention as defined in the claims which follow.

Claims

1. An electrical contact element, for connection to unstripped cable, including a trough shaped part, a forked member cut from the base of said part so as to be upstanding and in the trough and abutting the walls thereof, the arms of the forked member being so shaped that, upon the insertion of a suitable unstripped cable between the arms of the fork, the arms, which are thereby pressed into closer contact with respective walls of the trough, bite through the unstripped insulation into the conductor core of the cable, means beinq provided to restrain the cable against withdrawal from the element as a result of a force tending to pull the cable and the element apart.

2. A contact element as claimed in claim 1 wherein the means to restrain the cable against withdrawal includes inwardly projecting tongues formed from the side walls of the trough shaped part.

3. A contact element as claimed in claim 1 wherein the means to restrain the cable against withdrawal includes a second forked member, cut from the base of said trough-shaped part so as to be upstanding in the trough, the arms of the second forked member being so shaped that, upon the insertion of said suitable unstripped cable between the arms of the second forked member, the arms of the second forked member, which are thereby pressed into closer contact with respective walls of the trough, bite into the insulating sheath of the cable but not into the conductor core of the cable.

4. A contact element as claimed in any one of the preceding claims wherein the opening between the arms of the or each of the forked members is greater at the top than at the bottom, sloping shoulders providing a transition between the openings at the top and bottom.

5. A contact element as claimed in claim 3 wherein the side walls of the trough shaped part are bent inwardly at their ends in order to support the second forked member.

6. A contact element as claimed in any one of the preceding claims wherein the trough shaped part has an outwardly projecting tongue for use in locking - 6 41794 the contact element in a mounting.

7. A contact element substantially as herein described with reference to Fig. 1 and Fig. 2 or Figs 3 and 4 of the accompanying drawings.