GB2079547A

GB2079547A - Electric connectors

Info

Publication number: GB2079547A
Application number: GB8119193A
Authority: GB
Original assignee: BICC PLC
Current assignee: Balfour Beatty PLC
Priority date: 1980-06-25
Filing date: 1981-06-22
Publication date: 1982-01-20
Also published as: GB2079547B

Abstract

An electric connector includes a first metallic support member 9 comprising a disc 10 having open slots (13) and fins 11. Individual contact units 5, previously secured to respective cable conductors 1, are moved laterally into the slots 13, so obtaining easy alignment, and secured there by a second metallic support member 15. The connector is primarily for heavy conductors that are difficult to push into alignment with a simple apertured support. The support members may also provide screening. <IMAGE>

Description

SPECIFICATION Electric connectors and methods of assembling them This invention relates to two-part electric connectors for multiconductor cables, for example plugs, sockets, and bayonet and other butt contact connectors. More specifically it relates to connectors for use with conductors that, on account of cross-section or material or both, require the application of considerable forces to deflect them. In the usual case of annealed copper or aluminium conductors, the invention is likely to be applied to connectors with a current rating of 50 amperes and upwards.

In using most present designs of such connectors, the end of each cable conductor has to be prepared by stripping insulation, and screening, if any, after which a suitable contact fitting may be separately secured to each of them; the various prepared ends must then be sufficiently aligned to allow assembly with an axially-presented common support that determines the spacing of the contacts in the finished connector.

Such alignment is difficult to obtain whenever the conductors become too stiff to be bent and inserted one by one by axial movement of their ends and either too stiff or too numerous to be simultaneously bent to the required alignment by forces that can be applied with the fingers of one hand.

The present invention greatly simplifies the process of positioning and alignment, and also facilitates the provision of a barrier against short circuits between adjacent contacts, when required.

As used herein, the 'front' of a connector means the end that is presented to a cooperating connector to mate them, and 'rear' is to be construed accordingly.

The connector in accordance with the invention comprises: a separate contact unit for each conductor, each contact unit having a rear-facing shoulder; a first support member having a slot for each contact unit that is laterally open at one end and closed at the other end and of such shape and dimensions that the respective contact unit, after mounting on its conductor, can be inserted into the slot from its open end to rest securely in the closed end of its slot with its shoulder engaging the first support member; and a second support member that is engageable with the contact units when resting in the closed ends of respective slots to secure them against movement away from the closed ends.

The invention includes a method of assembling the connector just described with a prepared cable end, comprising first securing a contact unit to each conductor end; next inserting the first support member between the contact units and entering each contact unit in turn into a respective slot until it rests securely in the closed end thereof; and then securing the second support to the so-aligned contact units.

It also includes the connector when assembled on the cable end.

If the support members are both made of insulating material, they may provide sufficient insulation between the contacts; in other cases appropriate insulation will be needed and preferably takes the form of a respective insulating sleeve forming part of each of the contact units and surrounding the currentcarrying part of the unit; in most cases the insulating sleeve will also provide the required shoulder.

The contact units and the first or second support member are preferably so shaped that they resist relative rotation when engaged with one another.

In most cases the first support member will comprise a slotted disc of circular or other section; the slots may extend radially or obliquely to the local radius. Preferably the sides of the slots that engage the shoulders of the contact units are shaped to provide a lead-in for the shoulders and/or to offer some resistance to movement of the contact units away from the closed ends of the slots, for example by chamfering the edges of an otherwise planar disc and/or by providing resilient interlocking formations.

The first support member will normally be positioned rearwardly of the second, and in this case it may include, or support, means forming a physical and/or electrical barrier between adjacent contact units. Such a barrier is preferably metallic and connected to earth, though an insulating coating or covering may be advantageous in providing adequate phaseto-phase clearances more easily; a convenient form comprises a number of fins radially disposed and united in the region of the central axis of the connector. The second support member preferably also provides a barrier between the contact units, and the two support members may together provide a continuous barrier from a position forward of the front end of the contact units to a position to the rear of the cut-back end of the core screens of the cable, when present.

This invention will be further described, by way of example, with reference to the drawings in which: Figure 1 is a longitudinal section of one form of three-phase mining connector in accordance with the invention for service at about 3kV; Figure 2 is a cross-sectional view on the line A-A in Fig. 1; Figure 3 is a longitudinal section, corresponding to Fig. 1, of the first support member of the connector; Figures 4 and 5 are opposite end elevations of the support member shown in Fig. 3, and Figure 6 is a view, corresponding to Fig. 1, of a similar connector for 6.6kV, 400A service.

The connector illustrated by Figs. 1 to 5 is suitable for use with a three-core cable with individually screened conductors of about 1 50 mm2 cross-section, and in assembling it the cable end if first cut back in the usual way to separate the cores 1 and to terminate the core screen and insulation at the point 2. A gland unit 3 is positioned about the cable and temporarily secured. To each prepared conductor end is secured contact unit 4, comprising a conventional metal contact 5 and an insulating sleeve 6 that provides an annular shoulder 7. Since there is almost unrestricted access at this stage, crimping or any other suitable connecting technique (such as soldering) can be used.

Three tie rods 8 are now screwed into the gland 3 and the conductor ends are bent outwards between them to allow insertion of the first support member 9. This (Figs. 3-5) is a zinc alloy die-casting and consists of a disc 10 and three fins 11 which are radially disposed and are united at the axis 1 2 of the support. To facilitate casting, the fins are slightly tapered. The disc 10 is formed with three radially-extending slots 1 3 (one for each contact unit), open to the outside and closed towards the axis 12, and adjacent the open end of each slot the disc is chamfered to provide ramps 14. This support member is pushed between the outspread cable cores and seated on the tie-rods 8.

The three cores are now brought, one by one, to the position shown in Figs. 1 and 2.

The dimensions are such that the shoulders 7 on the contact units bear first on the ramps 14 and then on the flat front face of the disc 10, resisting any tendency for the support member 9 to be pushed forward if the cores contact the rear end of the fins 11 and providing a sufficient grip to resist any tendency for the conductors to spring back and so to prevent the contact units from seating securely in the closed ends of the slots 13.

The contact units are now properly aligned, and a second die-cast support member 1 5 having a separate bore to receive each contact unit can be slid into place and screwed to the tie-rods 8.

The shoulders 7 have flats that are engaged when the connector is assembled so as to prevent rotation of the contact units and consequent twisting of the cable conductors.

The gland is now fixed in its final position.

A housing 1 6 which may be filled with an insulating compound (not shown) completes the connector. Note that a continuous earthed metallic barrier against phase-to-phase faults is provided by the two support members in conjunction with the core screens of the cable.

The connector illustrated in Fig. 6 follows precisely the same principles, and the same references have been used. However the gland 3 is of a type appropriate for a double wire armoured cable, and on account of the higher voltage the connection between each cable core and its contact unit has been appropriately taped.

If desired, the shoulder might be provided with small projections and the disc 10 with corresponding recesses to provide even more positive location of the contact units 4 in the closed ends of the slots 1 3.

Instead of being an integral die-casting as shown, the disc 10 and fins 11 might be separately formed by stamping and extrusion respectively and secured together by welding or otherwise.

Claims

1. A connector for a multiconductor cable comprising: a separate contact unit for each conductor, each contact unit having a rear-facing shoulder; a first support member having a slot for each contact unit that is laterally open at one end and closed at the other end and of such shape and dimensions that the respective contact unit, after mounting on its conductor, can be inserted into the slot from its open end to rest securely in the closed end of its slot with its shoulder engaging the support member; and a second support member that is engageable with the contact units when resting in the closed ends of respective slots to secure them against movement away from the closed ends.

2. A connector for a multiconductor cable comprising: a separate contact unit for each conductor, each contact unit having an insulating sleeve shaped to provide a rear-facing shoulder; a first metallic support member having a slot for each contact unit that is laterally open at one end and closed at the other end and of such shape and dimensions that the respective contact unit, after mounting on its conductor, can be inserted into the slot from its open end two rest securely in the closed end of its slot with its shoulder engaging the support member;; and a second metallic support member that is engageable with the contact units when resting in the closed ends of respective slots to secure them against movement away from the closed ends, the first support member being positioned rearwardly of the second and providing a barrier between adjacent contact units.

3. A connector as claimed in Claim 1 or Claim 2 in which the contact units and the first or second support member are so shaped that they resist relative rotation when engaged with one another.

4. A connector for a cable with at least three individually-screened cores substantially as described with reference to the drawings.

5. A method of assembling a connector with a multi-conductor cable end comprising: first securing a separate contact unit to each conductor, each contact unit having a rearfacing shoulder; next inserting between the contact units a first support member having a slot for each contact unit that is laterally open at one end and closed at the other end; then inserting respective contact units, each mounted on its conduct, into each slot from its open end to rest securely in the closed end of its slot with its shoulder engaging the support member; and then securing to the so-aligned contact units a second support member that engages them and secures them against movement away from the closed ends.

6. The method claimed in Claim 5 when used with the connector claimed in Claim 2 or Claim 3.

7. A method of assembling a cable having at least three individually-screened cores with a connector, substantially as described with reference to the drawings.

8. A connector assembled on the end of a multiconductor cable comprising: a separate contact unit mounted on each conductor, each contact unit having a rearfacing shoulder; a first support member having a slot for each contact unit that is laterally open at one end and closed at the other end, the respective contact unit resting securely in the closed end of its slot with its shoulder engaging the support member; and a second support member that is engaged with the contact units to secure them against movement away from the closed ends of their slots.

9. A connector assembled on the end of a multiconductor cable with individually screened cores comprising: a separate insulated contact unit mounted on each conductor, each contact unit having a rear-facing shoulder; a first metallic support member having a slot for each contact unit that is laterally open at one end and closed at the other end, the respective contact unit resting securely in the closed end of its slot with its shoulder engaging the support member; ; and a second metallic support member that is engaged with the contact units to secure them against movement away from the closed ends of their slots, the first support member being positioned rearwardly of the second and the first and second support members together providing a continuous barrier from a position forward of the front end of the contact units to a position to the rear of the cut-back end of the core screens of the cable.

10. A connector as claimed in Claim 8 or 9 in which the contact units and the first or second support member are so shaped that they resist relative rotation when engaged with one another.

11. A connector assembled on the end of a cable with at least three individuallyscreened cores, substantially as described with reference to and as shown in the drawings.