GB2305549A - Mechanical and elecrical connector - Google Patents

Abstract

A connector for mechanically and electrically connecting electrical cables has a channel-shaped housing (1) carrying a loosely retained clamping plate (5) and a support plate (2) slidably mounted between the walls of the channel. The support plate (2) has threaded orifices (3) for receiving clamping bolts (4) or screws which bear on the clamping plate (5) to clamp cables between the clamping plate (5) and the inner wall of the channel housing. The support plate (2) and channel housing have complimentary shaped mounting elements (6, 2'') which allow the support plate to be inverted in position between the channel walls. The orifice openings are on two opposing faces of the support plate, one of which is closer to the mounting element than the other. Thus the allowable screwable travel of the bolts towards the clamping plate to the shearing tension required is greater in one inverted position of the support plate than the other. Cables of a wider range of size than heretofore possible can thus be clamped by inverting the support plate to suit.

Description

MECHANICAL CONNECTORS The present invention relates to mechanical connectors for coupling electrical cables or wires.

In particular, the present invention relates to such connectors for use in mains distribution in an underground location. In such applications, the connector is finally encapsulated in a sealant material electrically to insulate the connection so formed.

A common type of mechanical connector in present day use is in the form of a U-shaped channel in which two cables to be connected may be assemhe channel has a loosely fitted pressure pad which can be clamped against the cables in the channel by means of shear off bolts screw mounted in a bolt support plate. The bolt support plate is slidably mounted transversely between the walls of the channel.

Single channel connectors are generally employed in straight through mains connectors where the cables to be connected are of similar size.

In some cases integrally formed side by side channel connectors are used to effect the electrical connection, each channel incorporating pressure pads and tensioning bolts as described above.

Such dual channel connectors have application. where, in a mains distribution network, an uncut main sector shaped conductor has to be electrically connected to a main branch conductor.

In the connectors of the prior art, to ensure an adequate connection is made either the respective channels have to be of an appropriate particular size to receive to the cables desired to be joined, or such measures will need to be resorted to as bending the cable ends double or "packing out", whereby a void in the connector is filled with the same conductive material.

It is an object of the present invention to provide a mechanical connector of the type described which is capable of handling cables which differ in size over a wider range than heretofore possible.

According to the invention there is provided a mechanical connector comprising a channel for receiving electrical cables to be connected, a clamping plate retained in the channel, clamping bolts or screws mounted in a support plate slidable between the walls of the channel to pennit the bolts to be tightened on the clamping means to secure the cables in the channel, characterised in that the support plate and the channel have cooperating mounting elements which permit the plate to be slidably mounted in an up-sidedown position in the channel, said support plate having a body portion or portions formed on one side thereof which are at a closer spatial distance from the inner channel wall than the other side thereof in one slidable position in the channel such as to extend the range of cable sizes which can be retained in the channel.

Other features and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention made with reference to the accompanying drawings wherein; Fig 1 is a cutaway perspective view of an electrical connector according to the invention; Fig 2 is an end elevation of the connector shown in Fig 1 with a bolt support bridge piece in a first position; and Fig 3 is an end elevation of the connector shown in Fig 1 with a bolt support bridge piece in a second position.

The electrical connector shown in the drawings is comprised of a U-shaped channel 1 for receiving the ends of cables (not shown) to be connected in abutting relationship.

The channel 1 contains a pair of bolt support bridge pieces 2, each bridging piece 2 being provided with two threaded orifices 3 as to receive two shear head clamping bolts 4 or screws having a shear throat. The shear throat is designed so that the head of the bolt 4 will shear from the threaded stem portion when the bolt 4 has been tightened to a predetennined tension corresponding to a sufficient clamping pressure.

It is, of course, possible to use bolts or screws without such a predetermined shearing capability, but this will render the correct clamping pressure more difficult to gauge.

The lower ends of the bolts 4 engage the top surface 5' of a pressure plate 5 loosely fitted within the channel 1, the underside surface 5" of which is convex.

The bridge pieces are in the form of flat plates 2 of rectangular cross section.

The sides of the plates 2 have a portion 2' in sliding fit with the inner surfaces of the walls of the channel 1 and another portion 2" in the form of dove-tailed flanges slidable in corresponding dove-tailed grooves 6 formed in the walls of the channel 1.

The support plates 2 are invertable in the grooves 6 such that that portion of the plate 2' in sliding fit with the walls of the channel 1 is either in an upward position with respect to the flange portion 2" as shown in Fig 2, or in a downward position as shown in Fig 3, so providing a variable upper surface level of the plate 2 with respect to the base of the channel 1.

With a given bolt length, therefore, the maximum depth of screwable movement through the support plate 2, and therefore the depth within the channel 1 of the pressure plate 5 contacted by the bolt 4 may be made variable depending on the inverted position of the plate 2 in the grooves. In this way the dimension of the channel portion for the cable to be received may be altered to suit the cable in hand.

This permits, for example, cables having a wide range of differing dimensions to be anchored in the channel 1 as the pressure plate 5 holds the cable against the channel base, by having the bolt support plates 2 in the position of Fig 2 to suit a larger range of cable size and in the inverted position of Fig 3 to suit a smaller range of cable size.

Furthermore the structure permits two cables of differing cable core crosssection to be anchored reliably and consistently in the connector by having one bolt support plate 2 in an inverted position with respect to the other.

In use the insulating layer is removed from each respective core to a length equal to that of the pressure plate 5. The core having been straightened, the connector is then assembled around the conductor by inserting the pressure plates 5 and bridge plates 2 as shown in the drawings whereby the bolts 4 may be tightened until such time as the shearing tension is reached whereupon the bolt head shears ensuring that a proper engagement has been made with the conductor.

The respective portions of the connector may be manufactured from any material having the requisite mechanical strength and providing the necessary electrical connection, for example typically aluminium.

Copper conductors may be wrapped in a brass gauze (not shown) prior to insertion in the connector to ensure electrical stability between the copper and aluminium.

The base of the U-shaped channel 1 may be grooved as to increase the degree of engagement as the pressure plate 5 tightens the cable occupying the channel 1 against its base.

Claims (8)

1. A mechanical connector comprising a channel for receiving electrical cables to be connected, a clamping plate retained in the channel, clamping bolts or screws mounted in a support plate slidable between the walls of the channel to permit the bolts to be tightened on the clamping means to secure the cables in the channel, characterised in that the support plate and the channel have cooperating mounting elements which permit the plate to be slidably mounted in an up-side-down position in the channel, said support plate having a body portion or portions formed on one side thereof which are at a closer spatial distance from the inner channel wall than the other side thereof in one slidable position in the channel such as to extend the range of cable sizes which can be retained in the channel.

2. A mechanical connector as claimed in claim 1 wherein the inner walls of the channel are provided with opposing grooves in which the support plate may slide in any inverted position thereof.

3. A mechanical connector as claimed in claim 2 wherein the support plate comprises a first body portion having flanges for engagement in the grooves which are of complimentary shape to the flanges, and a second body portion in sliding fit with the inner walls of the channel such that the second body portion presents a closer support plate face to the inner wall of the channel in one slideable position of the plate than the other.

4. A mechanical connector as claimed in claim 3 wherein the channel grooves and the support plate flanges are provided in the form of dovetail joints.

5. A mechanical connector as claimed in any preceding claim wherein the clamping plate and the support plate are provided in two halves such that each of the respective halves may be independently adjusted securely to retain the cables to be electrically connected.

6. A mechanical connector as claimed in any preceding claim wherein the screws or bolts have tension dependent shearing heads to ensure that a correct tightening pressure is applied to the clamping plate.

7. A mechanical connector as claimed in any preceding claim wherein the channel is U-shaped.

8. A mechanical connector substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.