NZ237814A

NZ237814A - Insulation-displacement connector with jaws having v-shaped pairs of symmetrically arranged transverse teeth

Info

Publication number: NZ237814A
Application number: NZ237814A
Authority: NZ
Inventors: Eric Dominique Sauer
Original assignee: Eric Dominique Sauer
Priority date: 1990-04-12
Filing date: 1991-04-12
Publication date: 1994-05-26
Also published as: AU7434891A; NO304767B1; NO911411L; NO911411D0; FR2661045B1; PT97352B; PT97352A; FR2661045A1

Description

237 8 1 4 Prioriiy Dslo(s): . JflS? j j 0 K). . n 2 6 MAY 1394 Publication Date: , P.O. Journal, No: ..... jj ^ No: Dates: i NEW ZEALAND • •/ ! s - <:•] Patents Act 1953 \ i 2APR}99J COMPLETE SPECIFICATION ' ?•' , ?%? f A CONNECTOR DEVICE FOR CONNECTING A NON—STRIPPED ELECTRIC CABLE .poHiA-f' Q<J £ I, ERIC (P-, SAUER, a French citizen of 16, rue J.B. Clement, 08110 Carignan, France do hereby declare the invention, for which I pray that a Patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- -1- (followed by la) 2378 14 A CONNECTOR DEVICE FOR CONNECTING A NON-STRIPPED ELECTRIC CABLE The present invention relates to a connector device for electrically connecting a cable constituted by a metal core surrounded by an insulating covering without requiring the 5 cable to be stripped, the device comprising a pair of jaws fitted with sharp members at least some of which are conductive, which members are disposed so as to engage opposite regions of the periphery of a cable inserted between the jaws and to penetrate the insulating covering to make contact with 10 the cable core when the jaws are moved towards each other by clamping.

Connection devices of this type are known having jaws including groups of spikes pointing towards each other in the clamping direction. Such devices suffer from several 15 drawbacks: they do not center the cable to which a connection is to be made, thereby requiring the cable to be held in the proper position while the connection operation is being performed; they apply concentrated pressure forces to the cable in 20 two small diametrically opposite regions of its periphery, thereby crushing the cable; the disposition and the size of the spikes must match the diameter of the conducting core of the cable, which varies for given section depending on whether the core structure is solid 25 or stranded; they are unsuitable for making connections to stripped stranded cables since the component strands, no longer held together by the covering, splay out when the jaws are clamped together; and they are suitable for cables of circular section, only.

To remedy these drawbacks, the present invention provides for the sharp members carried by the jaws to be constituted by flat teeth each situated in a plane that extends transversely relative to the axial direction of a cable to be connected, and 35 preferably perpendicularly to said direction, the teeth being combined in pairs, with the teeth in each pair having cutting edges facing each other obliquely relative to the direction in 2 3 7 8 1 4 which the jaws clamp onto the cable and being disposed symmetrically on either side of the midplane of the cable parallel to said direction, with at least one tooth in at least one jaw having a cutting edge which is conductive, thereby enabling 5 electrical contact to be made with the core of the cable.

A connector device as defined above has the following advantages: the cable benefits from an automatic centering effect because the opposite pairs of flat teeth are no longer applied 10 in two regions only, but are applied in four regions distributed around its periphery; for the same reason, the cable is subjected by the opposite pairs of teeth to four converging forces distributed around its periphery and which tend to maintain cable cohesion 15 without crushing it; the flat teeth are equally suitable for cable cores that are solid or stranded; stripped cables and insulated cables are engaged identically by the pairs of flat teeth without any risk of the 20 strands of a stranded cable being splayed apart; and cables that are non-circular in section, such as sector-shaped cables for conveying three-phase electricity, can be engaged just as well as cables of circular section.

Thus, a connector device of the invention can be used with 25 cables that are stripped or insulated, that are solid or stranded, and that are circular in section or otherwise. In all cases, the operation of making a connection does not crush the cable, and on the contrary tends to keep it compact without changing its geometrical shape.

Surprisingly, it has also been observed that a connector of the invention gives rise to lower electrical contact resistance than that which can be obtained using a conventional device having spikes.

Although the cutting edges of the teeth of a device of the 35 invention may be rectilinear, they are preferably curved, having a convex outline such as a circular sector, e.g. a quarter circle, in which case the circular sectors defining the 23 7 8 1 outlines of the cutting edges of the teeth in the same pair may belong to two equal circles that are tangential or slightly spaced apart.

The teeth in the same pair may lie in the same transverse 5 plane or they may lie in two close-together transverse planes. In addition, the teeth of two opposite pairs belonging to respective ones of the jaws may face each other so as to be exactly opposite or they may be slightly offset in the axial direction of the cable to be connected, in which case a single 10 pair of teeth on one of the jaws may face two pairs of teeth on the other jaw, with the two pairs of teeth being slightly offset in the axial direction of the cable and lying on opposite sides of the pair of teeth on the first jaw.

In practice, facing pairs of teeth may be distributed in 15 distinct groups.

A device of the invention may be designed to interconnect two cables, e.g. a main cable and a branch cable, in which case the jaws have two systems of facing pairs of teeth disposed side-by-side for the purpose of interconnecting the two cables, 20 with at least one tooth in one of the systems having a conducting cutting edge which is electrically connected to a conducting cutting edge of a tooth in the other system.

Other features and advantages of the invention appear from the following description of non-limiting embodiments described 25 with reference to the accompanying drawings.

Figure 1 shows a prior art cable connector device seen end-on in the cable axis direction.

Figures 2 and 3 are similar to Figure 1 and show a connector device of the invention in two different jaw-clamping 30 positions.

Figure 4 is a view on arrow IV of Figure 2.

Figures 5 and 6 are similar to Figure 2 and show a variant embodiment.

Figure 7 is a cross-section through a device of the 35 invention designed to interconnect two cables.

Figure 1 shows a conventional connector device for an electric cable 1 comprising a metal core 2 surrounded by an 2 3 7 8 " insulating covering 3. This device comprises two jaws 4 and 5 each of which is fitted with metal spikes 6 facing in opposite directions on either side of the cable 1. When a clamping force F is applied to the jaws 4 and 5 causing them to move 5 towards the axis 7 of the cable 1, the spikes 6 perforate the covering 3 of the cable and come into contact with its core 2, establishing an electrical connection between the core and an apparatus 8 for which the device 4, 5, 6 constitutes a clamping connection terminal.

As explained above, such a device suffers from drawbacks due, in particular, to the absence of means for centering the cable between the jaws and means for maintaining cohesion of a core that is a stranded core.

Figure 2 shows a connection device capable of avoiding 15 these drawbacks. In this device which likewise comprises jaws 4 and 5, the contact members for perforating the insulating covering 3 of the cable 1 are now constituted by flat teeth 9 provided with cutting edges 10 and combined in pairs on each of the jaws 4 and 5. The two teeth 9 in each pair lie in a single 20 common plane perpendicular to the axis 7 of the cable 1 with their cutting edges 10 extending obliquely relative to each other so as to define a re-entrant angle between the pair of teeth 9 in which the teeth receive the cable 1 prior to penetrating therein. Thus, when the jaws 4 and 5 are caused to 25 move towards each other, each pair of teeth 9 comes into contact with the cable 1 at two points I and J which are spaced on either side of the midplane P of the device as a whole. The four contact points I, J, I, J of the two opposite pairs of teeth 9 define a rectangle which differs little in shape from a 30 square. As a result, the opposite pairs of teeth give rise to a centering effect on the cable 1, which effect continues as the teeth penetrate like knife blades into the covering 3 of the cable so that their cutting edges 10 come into contact with the cable core 2 (Figure 3). Under the effect of the clamping 35 force F applied to the jaws 4 and 5, the teeth 9 then apply four forces f on the core 2 along two intersecting transverse axes X and Y, which forces are equal and converge on the axis 7 23 78 of the cable. These four forces serve to maintain cohesion of the core 2 if it is constituted by a bundle of distinct strands, and this applies in particular if the cable is a stripped stranded cable, whereas the strands of such a cable 5 are splayed apart in detrimental disorder by the spikes 6 of the device shown in Figure 1 which engage the cable in two small diametrically opposite regions, only.

As shown in Figure 4, the opposite pairs of teeth 9 may occupy transverse planes which are slightly offset along the 10 direction of the axis 7 of the cable 1 to be connected. More precisely, each pair of teeth 9 belonging to the jaw 4 cooperates with two pairs of teeth 9 belonging to the jaw 5, with the planes of said two pairs lying on opposite sides of the plane of the first-mentioned pair. In addition, two axially 15 spaced-apart groups of such facing pairs of teeth are provided on the jaws 4 and 5. One pair of teeth in each group on the jaw 5 fixed to the apparatus 8 is made of metal (copper, aluminum, zamac, etc.), or at least the cutting edges of the corresponding teeth are made of metal, thereby electrically 20 connecting the cable to said apparatus, while the other teeth may be made of an insulating material such as a plastic or a composite. The number of conducting teeth is selected as a function of the current that is to flow through the connector device.

Figures 5 and 6 show a variant in which the teeth 9 of the jaws have a cutting edge 10' which is curved rather than being rectilinear, with each tooth being in the form of a circular sector extending over about 90°, the spacing C between the centers of two 1/4 circle teeth in the same pair being slightly 30 greater than twice the radius R of the circular sectors. The space outlined by the two pairs of facing teeth, which is diamond-shaped in the embodiment of Figures 2 and 3, now has a shape reminiscent of the cruciform curve. As can be seen in Figures 5 and 6, a device fitted with teeth having this shape 35 adapts particularly well to cables of different diameters. In practice, a device having teeth whose cutting edges are of radius R is suitable for receiving cables having diameters lying in the range about R/2 to about 2R. 237 8 6 Fi ~ 'lows a connector device for interconnecting two cables and pr1 and using contact members similar to those described above with reference to Figures 5 and 6. This device has two jaws 14 and 15 fitted with two systems A and B of pairs 5 of teeth 9a, 9b disposed side-by-side, with each system serving to make contact with a respective one of two cables la and lb. The teeth 9a of system A correspond to a main cable la and have edges 10'a that are larger in radius to the edges 10!b of the teeth 9b of the system B which corresponds to a normally 10 smaller diameter branch cable lb. Nevertheless, each of the connection systems A and B is suitable for receiving a wide range of different cable diameters. The jaw 15 has a guide tube 11 which engages in an opening 12 included in the other jaw 14, which opening is flared going away from the cables to 15 enable the two jaws to tilt relative to each other when clamped together by means of a bolt 17 engaged in a nut 18, thereby accommodating various different diameters of cables la and lb to be interconnected. particular the teeth 9a and 9b are made of plastic. However, in order to provide electrical connection between the two cables, metal strips 16 are inserted in transverse notches provided in some of the pairs of teeth 9a, 9b situated in the same transverse plane and belonging both to the system A and to 25 the system B. Each strip 16 is shaped to have metal cutting edges 10"a and 10"b which replace the cutting edges of the corresponding teeth 9a, 9b that are eliminated by the notches for receiving the strips 16.

The two jaws 14 and 15 and the associated parts, in N il 6 FEB 1394 . RECEIVED

Claims

237814 WW AT "X- CuAl^ IS : -CLAIHO

1. / A connector device for electrically connecting a cable constituted by a metal core surrounded by an insulating covering^without requiring the cable to be stripped, the device 5 pompriGQ a pair of jaws fitted with sharp members at least some of which are conductive, which members are disposed so as to engage opposite regions of the periphery of a cable inserted between the jaws and to penetrate the insulating covering to make contact with the cable core when the jaws are moved 10 towards each other by clamping, wherein the sharp members carried by the jaws are constituted by flat teeth each situated in a plane that extends transversely relative to the axial direction of a cable to be connected, and preferably perpendicularly to said direction, the teeth being combined in 15 pairs, with the teeth in each pair having cutting edges facing each other obliquely relative to the direction in which the jaws clamp onto the cable and being disposed symmetrically on either side of the midplane of the cable parallel to said direction, with at least one tooth in at least one jaw having a 20 cutting edge which is conductive, thereby enabling electrical contact to be made with the core of the cable-

2. / A device according to claim 1, wherein the cutting ■ edges of the teeth are rectilinear. 25

3. / A device according to claim 1, wherein the cutting edges of the teeth are curved, being convex in outline.

4. / A device according to claim 3, wherein the outlines of the 30 cutting edges of the teeth are circular sectors, such as quarter circles.

5. / A device according to claim 4, wherein the circular sectors defining the outlines of the cutting edges of the teeth of any 35 one pair belong to two equal circles that are tangential or slightly spaced apart. FlD tS24 30 2378 14 8

6. / A device according to any one of claims 1 to 5, wherein the teeth of any one pair lie in a single transverse plane, or in two close-together transverse planes.

7. / A device according to any one of claims 1 to 6, wherein the teeth of two facing pairs belonging to different ones of the jaws face each other exactly, or with a small offset in the axial direction of the cable to be connected.

8. / A device according to claim 7, wherein a single pair of teeth in one of the jaws faces two pairs of teeth in the other jaw, said two pairs of teeth being slightly offset from each other in the axial direction of the cable and lying on opposite sides of the single pair of teeth of the first jaw.

9. / A device according to any one of claims 1 to 8, wherein facing pairs of teeth are split up into distinct groups.

10. / A device according to any one of claims 1 to 9, wherein the jaws include two facing systems of pairs of teeth situated side-by-side to enable two cables to be interconnected, with at least one tooth in one of the systems having a conductive cutting edge which is electrically connected with a conductive cutting edge of a tooth of the other system.

11. / A connector device substantially as herein described with reference to and as illustrated in Figures 2 to 7 of the accompanying drawings. ERIC PK SAUER By his Attorney ffa 7 Don Hopkins ""li Registered Patent Attorney