GB2109180A

GB2109180A - Highway cable connector

Info

Publication number: GB2109180A
Application number: GB08231399A
Authority: GB
Inventors: Anthony Graham Gorman; John Richard Peacock
Original assignee: Racal Acoustics Ltd
Current assignee: Racal Acoustics Ltd
Priority date: 1981-11-04
Filing date: 1982-11-03
Publication date: 1983-05-25
Also published as: GB2109180B

Abstract

A connector which can make electrical connection to the wires in a highway cable (30) without cutting the cable is formed with two hinged members (10, 11) which can be closed together to make the connection. On closing, conducting needles (23, 24) penetrate the insulation of the cable to contact the wire core. For a co-axial cable, the needle (23) for the central core is insulated except at the tip (26). In another embodiment, plates with sharpened V slots are used to penetrate the insulation of the two side-by-side cables in order to make contact with the conductors therein. Spongy seal members may be mounted on each member (10, 11) to seal the areas of the cables which are penetrated. <IMAGE>

Description

SPECIFICATION Highway cable connector The present invention relates to a highway cable connector for making electrical connection to a conductor in a length of insulated highway cable at a point intermediate to the ends of the length of the cable.

According to the invention the highway cable connector comprises a pair of interconnected members which are movable relative to one another between open and closed positions, electrically conductive cutting or penetrating means mounted on at least one of said members, said members being formed to receive the highway cable with the members in the open position, to present the cable to said cutting or penetrating means and to press the cable against said cutting or penetrating means when the members are moved to the closed position, whereby on closing the members said means cuts or penetrates through the insulation of the cable to make contact with the conductor, and a terminal enabling electrical connection to be made to said cutting or penetrating means. With this connector, connections can be made intermediate the ends of a length of highway cable without breaking the cable.

This is especially useful when connecting telephone apparatus to a communication cable as will become apparent.

In a preferred arrangement, one of said members is a die member formed with a groove sized to receive and locate the highway cable against transverse movement relative to the die member, and said cutting or penetrating means comprises at least one electrically conductive needle point upstanding from the base of the groove, the other of said members having a ram positioned to bear against the cable on moving the members to the closed position and to press the cable into the groove and onto the needle point so that the point pierces the insulation of the cable and makes connection with the conductor.The pair of members may be hinged to one another about an axis parallel to the groove and then the ram is preferably mounted on said other of the members such that the ram can move substantially linearly into the groove at least over a final arc of relative movement of the members to the closed position.

In one embodiment providing a connector for making respective connections to the screen and core conductors of a co-axial cable, said cutting or penetrating means comprises a first said needle point located centrally in the groove and having an electrically insulating coating except at the tip, and a second said needle point located off-centre in the groove but aligned parallel to the first needle point, whereby on moving said members to the closed position said first needle pierces the insulation of the cable and penetrates through the screen conductor to make electrical contact only with the core conductor and said second needle point pierces the insulation and makes contact only with the screen conductor.Athird said needle point may be included corresponding to and electrically connected to said second needle point and located off-centre in said groove but spaced along said groove from said second needle point. It will be understood that the screen conductor of co-axial cable commonly includes a loosely braided conductor structure so that it is theoretically possible that said second needle point may fail to make contact with the braided screen conductor of some co-axial cables. By providing two electrically interconnected off-centre needle points, the risk of failing to make contact with the screen conductor is greatly reduced.

In a different embodiment, said cutting or penetrating means comprises at least two V-shaped members, mounted on one of said members and arranged to receive respective insulated wires of a multiwire highway cable, and the other of said members having abutment means arranged to bear on the wires and press the wires into the V's of the V-shaped members on closing the members of the connector, whereby the insulation of the wires is displaced by the V-shaped members to make electrical contact between the V-shaped members and the wire conductors.Preferably resiliently deformable seals are mounted on each of the relatively moveable members of the connector so as to cooperate with one another and, on closing the members, make a moisture tight seal between the members and around the wires of the highway cable to prevent ingress of moisture to the connections between V-shaped members and wire conductors.

Then, said relatively moveable members of the connector may be formed to locate the respective seals mounted thereon and to apply additional squeezing pressure on the seals, on closing the connector, immediately adjacent the wires of the highway cable.

An example of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a side elevation of a highway cable connector embodying the present invention and Figure2 is a view of the connector of Figure 1 taken along arrow.

Figure 3 is a perspective view of a different embodiment of the invention.

Figures 4 and 5 are detailed cross-sectional views of part of the embodiment of Figure 3.

Referring to Figure 1, the illustrated connector has members 10 and 11 hinged together at pivot 12. The members 10 and 11 are illustrated primarily in an open position but are also shown in Figure 1 in ghost in the closed position.

Member 10 comprises a base in the form of a die having a transverse groove 13 extending across the width of the base. The groove has a width selected to correspond substantially with the diameter of a co-axial cable forming the highway cable with which the connector is designed to make connections.

The member 11 is formed as a channel comprising side flange portions 14joined buy a single elongate web portion 15. The web portion 15 may be cut away at the end of the member 11 adjacent the pivot 12 to enable the member 11 to adopt the open position illustrated in Figure 1. Mounted between the side flanges 14 of the member 11 is a ram 16. The ram 16 comprises a plate-like member having a thickness corresponding to the width of the groove 13. A lower end 17 of the ram is machined to have a cylindrical concave profile so as to match the cylindrical profile of the highway cable with which the connector is to be used. As can be best seen from Figure 2, the ram 16 extends substantially the full length of the groove 13.

The ram 16 has a pair of sutds 18 on each end face fitting in corresponding grooves 19 provided through the side flanges 14 of the member 11. The hemispherical stud 20 is fastneed midway across the width of the web piece 15 of the member 11, as best seen in Figure 2. The upper end edge 21 of the ram 16 is machined to have a cylindrical convex profile as shown in Figure 1. The grooves 19 are arranged to be substantially horizontal when the member 11 is in the open position as illustrated in Figure 1, such that the grooves are substantially vertical when the member 11 is in the fully closed position as shown in ghost in Figure 1.

Mounted on the base 22 of the groove 13 are needle points 23,24 and 25 (see Figure 2). Each of the needle points 23-25 are aligned parallel to the depth and transversely of the length of the groove.

The needle point 23 is located centrally of the width of the groove and has a length not substantially greater than half the diameter of the co-axial highway cable with which the connector is designed to be used. The needle point 23 is provided with an electrically insulating coating over the major part of its length above the base of the groove 13, except at the tip 26. The insulating coating is conveniently a thin glazing, which may be only a few microns thick, provided by painting the needle with a glass frit, and then firing the painted needle to dry off and vitrify the frit as a glass coating on the surface of the needle point.

Each of the needle points 24 and 25 are uncoated.

They are arranged to be parallel to the needle point 26 but located off-centre in the groove 13 and spaced apart one from the other along the length of the groove as shown in Figure 2. The positioning of the needle points 24 and 25 relative to the centre line of the groove 13 is quite critical. It is important that the needle points 24 and 25 should not be so close to the centre line of the groove that they can make contact with the core conductor of the co-axial highway cable with which the connector is designed to be used. On the other hand the needle points 24 and 25 should not be so close to the sides of the groove 13 that they fail to pierce the outer insulation of the co-axial highway cable sufficiently to make contact with the screen conductor of the cable.

The needle point 23 is connected via a terminal to the core conductor 27 of a co-axial cable 28 leading to the equipment which it is desired to connect to the highway cable by means of the connector. The two needle points 24 and 25 are connected together and via a further terminal to the screen conductor 29 of the co-axial cable 28.

In operation, the connector illustrated is presented to the highway cable to which connection is desired with the member 11 in the open position as shown in Figure 1, and the highway cable is inserted in the groove 13. The member 11 is then closed by rotating in the clockwise direction in Figure 1 relative to the base member 10 of the connector. This clockwise closing movement of the member 11 causes the ram 16 to enter the groove 13 and the concave end face 17 of the ram to bear against the upper surface of the highway cable in the groove. Continued closing action of the member 11 causes the ram 16 to press the highway cable into the groove so as to be pierced by the needle points 23, 24 and 25 until the highway cable is pressed fully home into the groove and adopts the position shown in ghost at 30 in Figure 1.In this position, the needle point 23 penetrates through the outer insulator of the highway cable and also through the screen conductor.

However, the insulating coating on the needle point 23 prevents electrical contact between this needle point and the screen conductor of the highway cable.

The uninsulated tip 26 of the needle point however makes electrical contact with the core conductor of the highway cable as illustrated in Figure 1. The two off-centre needle points 24 and 25 penetrate through the outer insulation of the highway cable and at least one of them normally makes contact with the braided screen conductor of the cable. Thus, electrical contact is made to the core and screen conductors respectively of the highway cable without breaking the cable.

On closing the member 11, it can be seen that the hemispherical stud 20 bears against the convex cylindrical end 21 of the ram 16. The slots 19 in the side flanges 14 of the member 11 permit the ram 16 to move angularly relative to the member 11 so that the ram 16 can adopt a purely linear motion down into the groove 13 at least over the final arc of the closing movement of the member 11. The outer edge of the groove 13 on the side of the groove adjacent the pivot 12 is rounded off in a circular profile as illustrated in Figure 1 so as to permit the ram 16 to slide over this edge into the groove during the closing movement of member 11.

In order to keep the connector firmly closed and maintain good connection with the highway cable, a spring clip 31 is provided fastened to the base member 10 of the connector and arranged to clip over an outer end 32 of the member 11 when in the fully closed position.

Although the above described embodiment is applicable to making connection to co-axial highway cables, corresponding connectors for making connections with other forms of highway cables are also envisaged. For example, a connector for making electrical connection to the wires of a twisted pair highway cable may have a pair of laterally spaced V-shaped members made from an electrically conducting material and sharpened along the opposed inwardly directed edges of the V's of the members.

Then each conductor of the twisted pair can be inserted into a respective V-shaped member and on closing the connector, the conductors are pressed down to the bases of the V's so that the knife edges cut through the insulation of the cales and make electrical contact with the conductors.

A particular example of connector for connecting to the wires of a twisted pair highway cable is illustrated in Figures 3 to 5. The connector has hinged members 30 and 31 corresponding to the members 10 and 11 of the example illustrated in Figure 1. The member 30 is formed with two transverse grooves 32 and 33 substantially parallel to the axis of the hinge 34 between the members 30 and 31. The grooves 32 and 33 are sized to receive the individual wires of a twisted pair cable. It will be appreciated that the twisted pair is untwisted for a short length to enable the wires pair to be located in the respective grooves 32 and 33 and extend out either side of the member 30 through slots 35 in raised side flanges 36 formed upstanding from the member 30.

Metallic V-shaped members 37 and 38 are positioned one aligned with each of grooves 32 and 33 to receive a respective wire of the highway cable. The V-shaped members 37 and 38 are spaced apart along the grooves 32 and 33 as illustrated in the drawing.

The member 30 is formed in the region of the grooves 32 and 33 and the V-shaped members 37 and 38 with locating blocks 39 to 43. The member 31 of the connector is formed on the underside as shown in the drawing with two pairs of pressure blocks 44 and 45 positioned to correspond with respective V-shaped members 37 and 38, so that on pivoting the member 31 to close the connector, the pairs of blocks 44 and 45 engage respective wires of the cable on both sides of the V-shaped members to force the wires down into the V's of the members.

The V-shaped members 37 and 38 are formed with opposed inwardly directed edges which displace the insulation cover of the wires as the wires are pressed down towards the bases of the V's. The base of the V of each member is sized to be just smaller than the diameter of the conductor in each wire of the highway cable, so that when each wire is fully pressed down into the respective V-shaped member, the insulating cover is completely displaced and connection is made by the V-shaped member to the conductor of the wire. In practice, the opposed inwardly directed edges of the V's of the members 37 and 38 need not be sharp in the sense of being razor edged. Indeed excessively sharp members would tend to cut right through the metal conductors of the wires.Thus, the inwardly directed edges of the V's may have a substantially flat profile, almost parallel or slightly angled relative to the wire engaged by the V-shaped member. The profile of the edge may be similar to that of the edge of the one blade of a pair of scissors.

It is desirable to form a seal completely around the region where the insulation of the wires of the highway cable is being cut into by the V-shaped members 37 and 38. To this end, a shallow rectangular cross-section groove 46 is formed completely encompassing the V-shaped member 37 and 38. The groove is formed as a square in the illustrated example. A square shaped seal member 47 is securred in the groove 46. The seal 47 is conveniently of a spongy material and is arranged to have a natural, undistorted thickness so that the seal 47 extends just above the level of the groove 46. The seal 47 co-operates with a corresponding square seal member 48 located on the member 31.Thus, when the member 31 is rotated to close the connector, the seals 47 and 48 engage each other and are compressed to make moisture proof seals completely around the connection region and in particular around the wires of the highway cable located in the grooves 32 and 33.

Figures 4 and 5 illustrate the sealing arrangement in more detail. As can be seen, the material of the members 30 and 31 immediately under the spongy seal members 47 and 48 is profiled to enhance the sealing effect and to accommodate material of the seals 47 and 48 displaced by the presence of the wires 49 and 50. Thus, enlarged portions 51 and 52 are formed to accomodate seal material displaced by the wires 49 and 50 and raised portions 53 and 54 are formed immediately adjacent the enlarged portions 51 to ensure extra compression of the seal material around the wires.

In the example of connector illustrated in Figure 3, provision is made in a housing region 55 which is closed by the member 31, to accomodate for example patches of insulating material for use in repairing the damaged insulation of the highway cable when the highway connector is disconnected and removed. The housing area 55 may also accomodate spare fuses for use in the connector.

Claims

1. A highway cable connector for making electrical connection to a conductor in a length of insulated highway cable at a point intermediate to the ends of the length of cable, comprising a pair of interconnected members which are moveable relative to one another between open and closed positions, electrically conductive cutting or penetrating means mounted on at least one of said members, said members being formed to receive the highway cable with the members in the open position, to present the cable to said cutting or penetrating means and to press the cable against said cutting or penetrating means when the members are moved to the closed position whereby on closing the members said means cuts or penetrates through the insulation of the cable to make contact with the conductor, and a terminal enabling electrical connection to be made to said cutting or penetrating means,

2.A connector as claimed in Claim 1 wherein one of said members is a die member formed with a groove sized to receive and locate the highway cable against transverse movement relative to the die member, and said cutting or penetrating means comprises at least one electrically conductive needle point upstanding from the base of the groove, the other of said members having a ram positioned to bear against the cable on moving the members to the closed position and to press the cable into the groove and on to the needle point so that the point pierces the insulation of the cable and makes connection with the conductor.

3. A connector as claimed in Claim 2 wherein the pair of members are hinged to one another about an axis parallel to the groove and the ram is mounted on said other of the members such that the ram can move substantially linearly into the groove at least over a final arc of relative movement of the members to the closed position.

4. A connector as claimed in Claim 2 or Claim 3 and for making respective connections to the screen and core conductors of a co-axial cable, wherein said cutting or penetrating means comprises a first said needle point located centrally in the groove and having an electrically insulating coating except at the tip, and a second said needle point located off-centre in the groove but aligned parallel to the first needle point, whereby on moving said members to the closed position said first needle point pierces the insulation of the cable and penetrates through the screen conductorto make electrical contact only with the core conductor and said second needle point pierces the insulation and makes contact only with the screen conductor.

5. A connector as claimed in Claim 4 and including a third said needle point corresponding to and electrically connected to said second needle point and located off-centre in said groove and spaced along said groove from said second needle point.

6. A connection as claimed in Claim 1 wherein said cutting or penetrating means comprises at least two V-shaped members mounted on one of said members and arranged to receive respective insulated wires of a multiwire highway cable, and the other of said members having abutment means arranged to bear on the wires and press the wires into the V's of the V-shaped members on closing the members of the connector, whereby the insulation of the wires is displaced by the V-shaped members to make electrical contact between the V-shaped members and the wire conductors.

7. A connector as claimed in Claim 6 wherein resiliently deformable seals are mounted on each of the relatively moveable members of the connector so as to co-operate with one another and, on closing the members, make a moisture tight seal between the members and around the wires of the highway cable to prevent ingress of moisture to the connections between V-shaped members and wire conductors.

8. A connection as claimed in Claim 7 wherein said relatively moveable members of the connector are formed to locate the respective seals mounted thereon and to apply additional squeezing pressure on the seals, on closing the connector, immediately adjacent the wires of the highway cable.

9. A highway cable connector substantially as hereinbefore described with reference and as illustrated in Figures 1 and 2 or Figures 3 to 5 of the accompanying drawings.