GB2287366A - Cable terminations - Google Patents

Abstract

A cable termination comprises a body (1) of electrically insulating material having a pair of opposite major faces (2, 3) and a plurality of tubular metal bushes (8 - 11) embedded in the body so as to be exposed to both those faces for the passage of terminal bolts or the like. The end of a multicore cable (12) is embedded in the body and each of its cores is electrically connected within the body to a respective one of the bushes. The body (1) is flexible in a direction transverse to its major faces but resistant to bending in any other direction. The termination can be applied to equipment having terminal bolts (18, 19) in two or more planes with minimal risk of error, even in the difficult conditions typical of railway installation and maintenance work. <IMAGE>

Description

Cable Terminations This invention relates to terminations of multicore electric cables that are to be connected to electrical equipment by connecting bolts or the like. It is concerned primarily with terminations of relatively large flexible cables such as are used to connect signalling and low-voltage auxiliary power circuits in rail transport installations.

Installation and maintenance of railway electrical equipment is almost always done at night and often in cramped conditions and/or outdoors in bad weather. Conventional terminations in which the individual cores of the cable are merely exposed, cut to the required length and fitted with a termination lug are often difficult to manipulate under such conditions and may sometimes allow the cable cores to be connected in an incorrect order, which at best results in delay for correction and at worst may be dangerous if undetected.

For track circuit terminations, the applicants have used preformed terminations in which the exposed parts of the cable cores are embedded in a slab of stiffly resilient electrically insulating material and connected to tubular metallic bushes which extend through the slab and are positioned to receive connecting bolts in predetermined positions, and this principle can be used for other connections where the flat form of the slab is compatible with the design of the equipment to which the cable is to be terminated. In this way, the installer is able to manipulate the cable end as a whole, without any need to manipulate individual core ends, and if the design of the equipment allows the predetermined positions of the bushes to be unsymmetrical, the possibility of connection in the wrong order can be substantially eliminated.

The present invention seeks to provide comparable benefits for terminations to equipment in which the individual cores need to be connected at points that are at two or more different levels.

The termination in accordance with the invention comprises a body of electrically insulating material having a pair of opposite major faces and a plurality of tubular metal bushes embedded in the body so as to be exposed to both those faces for the passage of terminal bolts or the like, the end of a multicore cable being embedded in the body and each of its cores being electrically connected within the body to a respective one of the bushes, and is characterized in that the body is flexible in a direction transverse to its major faces but resistant to bending in any other direction.

Preferably the body is shaped to form at least two lobes each accomodating at least one of the bushes and each lobe being individually flexible in the required direction to allow the bush or bushes in that lobe to be brought to the required level with respect to the other bush or bushes.

Preferably (whether the body is formed with lobes or not) the bushes are located near a pair of opposite ends of the body and the flexibility of the body is such that it can be bent by hand until those opposite ends overlie one another.

This arrangement is particularly suitable for use, for example, when the equipment to be connected has connecting bolts or the like arranged in two rows with the rear row raised above the front row.

The invention will be further described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a perspective sketch of one form of cable termination in accordance with the invention as manufactured, Figure 2 is an end view showing it as bent to shape for connection to equipment having rear upper and front lower rows of terminal bolts; and Figures 3 and 4 are corresponding views of a second form of cable termination in accordance with the invention.

The termination of figures 1 and 2 comprises a body 1 of approximately H shape having opposite major faces 2,3 and subdivided into lobes 4,5,6,7 in each of which is embedded a respective brass bush 8,9,10,11 so that bushes 5 and 6 are located close to one end of the body and bushes 7 and 8 close to the opposite end of the body. The end portion of a cable 12 is embedded in the body (which may be locally enlarged as seen at 13 to accomodate it, if appropriate in particular applications) and its cores 14,15,16,17 are connected respectively to the bushes 8,9,10 and 11. The material of the body (an appropriately selected rubber or thermoplastic material) and the widths of the lobes are such that the body is easily bent by hand transversely to the major faces 2,3 but the lobes are not easily bent in their own planes (and if so bent spring back), so that the spacing of the bushes is stable in handling.

The installer needs first to ensure that the termination is the right way up (if it is not sufficiently assymmetric to make this easy, it may be provided with visible and/or tactile marks to assist: for example one major face may be smooth and the other ribbed) and then to present the short lobes 4,5 to the lower set of terminal bolts 18 (Figure 2), insert those bolts through the bushes 8,9 and secure them with nuts (not shown); the long lobes 6,7 can then be bent upwards and over to overlie the short ones, and the bushes 10,11 fitted onto the upper set of terminal bolts 19 and secured with nuts (not shown).

The individual lobes can be bent, within limits, to accomodate equipment in which the terminal bolts are at more than two different levels.

In the alternative form of termination shown in Figures 3 and 4, the cable 12 enters the body 1 not in its central region but at the end of an additional lobe 20; the additional flexibility is beneficial primarily when the cable is to extend upwards and possibly over the top of the termination, as seen in Figure 4.

Claims (9)

1 A cable termination comprising a body of electrically insulating material having a pair of opposite major faces and a plurality of tubular metal bushes embedded in the body so as to be exposed to both those faces for the passage of terminal bolts or the like, the end of a multicore cable being embedded in the body and each of its cores being electrically connected within the body to a respective one of the bushes, characterized in that the body is flexible in a direction transverse to its major faces but resistant to bending in any other direction.

2 A termination as claimed in claim 1 in which the body is shaped to form at least two lobes each accomodating at least one of the bushes and each lobe is individually flexible in the required direction to allow the bush or bushes in that lobe to be brought to the required level with respect to the other bush or bushes.

3 A termination as claimed in claim 1 or claim 2 in which the bushes are located near a pair of opposite ends of the body and the flexibility of the body is such that it can be bent by hand until those opposite ends overlie one another.

4 A termination as claimed in any one of the preceding claims in which the major faces are distinguished by visible and/or tactile markings.

5 A termination as claimed in any one of the preceding claims in which the cable end enters the body at the end of a lobe thereof.

6 A cable termination substantially as described with reference to Figure 1.

7 A cable termination substantially as described with reference to Figures 1 and 2.

8 A cable termination substantially as described with reference to Figure 3.

9 A cable termination substantially as described with reference to Figures 3 and 4.