GB2355346A

GB2355346A - Electrical terminal assembly with catches

Info

Publication number: GB2355346A
Application number: GB0022661A
Authority: GB
Inventors: Peter Dent; Ian Charles Parry
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 1999-10-12
Filing date: 2000-09-13
Publication date: 2001-04-18
Also published as: GB0022661D0; GB9923989D0; EP1107393A2; EP1107393A3; CA2322351A1

Abstract

An electrical busbar terminal assembly has several hyperboloid spring sockets 21 to 32 mounted on a metal bar 20 spaced along its length. The sockets 21 to 32 extend along respective bores 13 of an insulating lower body 10 and the bar 20 extends along the bottom of the body being covered by a cover plate 12. The two end sockets 21 and 32 are larger than the others 22 to 31 and receive input power contacts 72 and 83 so that power is distributed from these sockets via the bar 20 to contacts 73 to 82 inserted in the other sockets. Catches 4 with inturned teeth (41, Fig 4) retain the contacts 72 to 83 after insertion. The catches 4 are located in bores in an upper closure 11 bonded to the lower body 10 and are trapped between the lower body and a step 44 in the upper closure. The catches 4 are electrically isolated from the sockets 21 to 32 until after insertion of a contact 72 to 83.

Description

2355346 ELECTRICAL CONNECTOR ASSEMBLIES This invention relates to

electrical connector assemblies.

The invention is more particularly concerned with busbar connector assemblies used to supply power between power lines.

Busbar connector assemblies have a power input socket and two or more power output sockets. A power source is connected with the assembly via a power line having a plug at one end, which is inserted in the input socket. Power is distributed to several pieces of electrical equipment via power lines plugged into the output sockets. The input and output sockets are usually fixed to a solid metal rod, or busbar, at their lower end by which power is supplied from the input sockets to the output sockets. The sockets are contained within an electrically-insulative housing having openings along its top through which the upper ends of the sockets are accessed.

The plugs and sockets are constructed such as to avoid inadvertent separation during use. The socket takes the form of a metal sleeve extending close to the open, upper end of the housing and having a locking catch at its upper end designed to latch onto a specially-shaped formation on the outside of the plug. Once inserted, a special tool is needed to release the catch and remove the plug. Busbar connectors of this kind are sold by Bumdy/Framatome Connectors International.

2 Several problems exist with conventional busbar connector assemblies. In particular, the plugs need to be of a special design in order to lock in the sockets and these are usually expensive. Other problems arise as a result of the locking catch being provided directly on the socket, which means that the catch itself is electrically live during use. Consequently, the distance between the openings at the top of the housing and the electrically-live internal components is relatively short. This increases the risk of inadvertently contacting the live components. Another problem is that any arcing between the plugs and sockets during insertion and withdrawal, when the assembly is live, occurs relatively close to the exposed parts of the assembly. A ftirther disadvantage is that the plug is electrically connected to the socket when only a short length of the plug is inserted, and that a relatively large part of the length of the plug is exposed and live.

It is an object of the present invention to provide an alternative electrical power terminal assembly.

According to one aspect of the present invention there is provided an electrical power terminal assembly including an electrically-insulating housing opening at one end and closed at its opposite end by an electrically-insulating member, a contact assembly within the housing and including a plurality of electrical contacts and a conductor interconnecting the contacts with one another, the contact assembly being located away from the open end of the housing with the conductor protected by the electrically-insulating member, the terminal assembly including a plurality of catch members located within the housing spaced from the contact assembly, the contact assembly being arranged electrically to contact respective cooperating contacts inserted in the housing through the open end such that power supplied to 3 one of the cooperating contacts flows to others of the cooperating contacts via the contact assembly, the catch members being arranged to engage the cooperating contacts and restrain withdrawal of the cooperating contacts, and the catch members being electrically isolated from the contacts of the contact assembly prior to insertion of the cooperating contacts.

The conductor is preferably a metal bar and the contacts of the contact assembly are preferably mounted in respective holes in the bar. The housing may include a lower body and an upper closure, the contacts of the contact assembly extending in bores in the lower body and the catch members being trapped between the lower body and the upper closure. At least one contact of the contact assembly may have a larger diameter than the others and may receive a power input contact. The assembly may include two contacts of larger diameter. The contacts are preferably sockets.

According to another aspect of the present invention there is provided an electrical power terminal assembly including a contact assembly including a metal bar and a plurality of sockets mounted on the bar spaced along its length, a lower electrically-insulating body having a plurality of bores extending through it, the sockets extending in respective ones of the bores with the bar extending along a lower end of the lower body, an electricallyinsulating cover member covering the bar, an upper electrically-insulating closure mounted at the upper end of the lower body and having a plurality of bores aligned with the bores in the lower body, and a catch member mounted in each bore and retained between the lower body and the upper closure, each catch member being arranged to engage a contact inserted within a bore to make contact with a socket, and the catch members being electrically isolated from the sockets prior to insertion of the contacts.

4 The sockets are preferably hyperboloid spring element sockets. The catch members may include a sleeve having an inclined tooth arranged to engage a part of a cooperating contact inserted in the assembly.

A busbar connector terminal assembly according to the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of the assembly; Figure 2 is a perspective, cut-away view of the assembly; Figure 3 is an exploded view of the assembly from one end; and Figure 4 is a sectional side elevation view of a part of the assembly.

The busbar assembly comprises an outer housing I of an electricallyinsulative material, an electrical socket assembly 2 within the lower end of the housing, and a number of retention clips or catches 4 located towards an upper end of the housing.

The housing I is of a generally rectangular shape comprising a main, lower body 10, an upper closure 11 and a bottom cover 12, all of an electrically-insulative plastics material, although it would be possible for the housing to be of a metal with an insulating insert. The main body 10 has twelve parallel bores 13 arranged side-by-side and extending up the entire height of the main body. The electrical socket assembly 2 is fitted in the main body 10 and is retained by the bottom cover 12, which fits in a rectangular recess 14 extending across the lower end of the body.

The socket assembly 2 includes a bar 20 of plated brass or other electricallyconductive material, which has a rectangular section and extends across the entire width of the housing 1, in the recess 14. The socket assembly 2 also includes twelve electrical sockets 21 to 32 equally spaced along the bar 20 and pressed into holes 33 through the bar so that they project at right angles and align with respective ones of the bores 13 in the main body 10 of the housing 1. The sockets 21 and 32 at opposite ends of the assembly 2 are slightly larger in diameter than the others 22 to 31 and are adapted to receive the input power to the busbar assembly. The sockets 21 to 32 are of the hyperboloid spring element kind, such as sold by Hypertac Limited of England under the Hypertac trade mark (Hypertac is a Registered Trade Mark of Hypertac Limited). The sockets have a cylindrical sleeve and several spring wires extending within the sleeve, which make electrical connection with a contact pin inserted in the socket. Hyperboloid sockets have a relatively high current rating and are highly reliable in adverse circumstances, although other sockets could be used. Typically, each socket 21 to 32 is about I Omm long whereas the housing I is about 3 5mm high, so it can be seen that the upper end of each socket is spaced from the upper, open end of the bores 13 by a considerable distance.

The retention clips 4 are in the form of short cylindrical sleeves 40 of a spring metal having three teeth 41 spaced around their circumference. The teeth 41 incline inwardly at their lower end at an angle of about 101. The retention clips 4 are located at the lower end of 6 the upper closure 11, in respective bores 43, which align with the bores 13 in the main body 10 of the housing. The lower end of each bore 43 is slightly enlarged to receive the clips 4 and to form a shallow annular step 44 about midway along its length. Each clip 4 is, therefore, trapped between a step 44 and the upper end of the main body 10. The clips 4 are electrically isolated from the socket assembly 2 until bridged by an inserted contact pin. The bores 43 in the upper closure I I open on the upper face 45 of the housing 1 via a row of twelve openings 46.

The upper closure I I and bottom cover 12 are bonded to the main body 10 such as by welding or an adhesive or solvent, so that the socket contact assembly 2 and the retention clips 4 are securely retained.

Externally, opposite ends of the housing I have an integral lug 50 with a vertical aperture 51 in which is received a metal mounting bracket 52.

The busbar assembly is used to make connection between twelve power lines 60 to 71 each of which is terminated by a male contact in the form of a crimp pin 72 to 83. The crimp pins 72 to 83 are of a conventional kind, such as MIL-C 39029 and are made of plated, machined brass. The pins are of circular section, the rear end of each having a cylindrical recess 90 within which an exposed conductor 91 in a power line 60 to 71 is inserted and crimped. The forward end of each pin is reduced in diameter to form a contact portion 92 of the appropriate size to make sliding connection in the appropriate socket 21 to 3 1. A shallow armular flange 93 projects externally around each pin 72 to 83 at the lower end of the crimp recess 90, the dimensions and location of the flange being selected so that the upper edge 94 7 of the flange is engaged by the teeth 41 of the retention clip 4 when the pin is inserted in full electrical contact with the socket 21 to 3 1. The pins 72 and 83 are connected to input power lines 60 and 71 and are larger in diameter than the other pins 73 to 82, which are connected to output power lines 61 to 70. The bores 43 in the upper closure I I are sufficiently long to ensure that the upper end of the pins 72 to 83 are entirely recessed within the bores.

In use, power from a power source (not shown) is supplied to the assembly on lines 60 and 71, via pins 72 and 83. These electrically connect with the sockets 21 and 32 at opposite ends of the assembly 2, so that power connection is established to the bar 20 and hence to each of the other sockets 22 to 3 1. The power thereby flows via the pins 73 to 82 to the output power lines 61 to 70 and hence to the electrical equipment supplied by those lines. The pins 72 to 83 can be removed from the terminal assembly by means of a conventional extraction tool having a channel of part-circular section that is threaded along the power line 60 to 71 into the upper part of the bore 43 and into the sleeve 40 of the retention clip 4 to push out the teeth 41, clear of the flange 93.

The hyperboloid sockets used in the assembly give a considerably improved electrical connection with the pins compared with previous assemblies. The pins can be conventional, thereby keeping costs to the user to a minimum. By separating the mechanical retention of the inserted contacts from the electrical interconnection, live components can be spaced from the open end of the housing. Thus, there is little risk of inadvertently contacting an unused, live power output socket. Connection can be made to the busbar assembly when live more safely than previously because very little of the inserted pins is exposed outside the housing when they are inserted far enough to contact the sockets. Furthermore, because contact is made and 8 broken deep within the housing, any arcing is also contained away from the open end of the housing.

Instead of a bar, the sockets could be electrically interconnected by other means, such as a wire. The contacts within the housing need not be sockets; they could, for example, be male components arranged to contact sockets inserted within the housing.

9

Claims

An electrical power terminal assembly including an electricallyinsulating housing opening at one end and closed at its opposite end by an electrically-insulating member, a contact assembly within the housing and including a plurality of electrical contacts and a conductor interconnecting the contacts with one another, the contact assembly being located away from the open end of the housing with the conductor protected by the electrically-insulating member, wherein the terminal assembly includes a plurality of catch members located within the housing spaced from the contact assembly, wherein the contact assembly is arranged electrically to contact respective cooperating contacts inserted in the housing through the open end such that power supplied to one of the cooperating contacts flows to others of the cooperating contacts via the contact assembly, wherein the catch members are arranged to engage the cooperating contacts and restrain withdrawal of the cooperating contacts, and wherein the catch members are electrically isolated from the contacts of the contact assembly prior to insertion of the cooperating contacts.
2. An assembly according to Claim 1, wherein the conductor is a metal bar.
3. An assembly according to Claim 2, wherein the contacts of the contact assembly are mounted in respective holes in the bar.
4. An assembly according to any one of the preceding claims, wherein the housing includes a lower body and an upper closure, wherein the contacts of the contact assembly extend in bores in the lower body, and wherein the catch members are trapped between the lower body and the upper closure.
5. An assembly any one of the preceding claims, wherein at least one contact of the contact assembly has a larger diameter than the others and receives a power input contact.
6. An assembly according to Claim 5, including two said contacts of larger diameter.
7. An assembly according to any one of the preceding claims, wherein the contacts of the contact assembly are sockets.
8. An electrical power terminal assembly including a contact assembly including a metal bar and a plurality of sockets mounted on the bar spaced along its length, a lower electrically-insulating body having a plurality of bores extending through it, the sockets extending in respective ones of the bores with the bar extending along a lower end of the lower body, an electrically-insulating cover member covering the bar, an upper electrically-insulating closure mounted at the upper end of the lower body and having a plurality of bores aligned with the bores in the lower body, and a catch member mounted in each bore and retained between the lower body and the upper closure, each catch member being arranged to engage a contact inserted within a bore to make contact with a socket, and the catch members being electrically isolated from the sockets prior to insertion of the contacts.
9. An assembly according to Claim 7 or 8, wherein the sockets are hyperboloid spring element sockets.
10. An assembly according to any one of the preceding claims, wherein the catch members include a sleeve having an inclined tooth arranged to engage a part of a cooperating contact inserted in the assembly.
11. An electrical power terminal assembly substantially as hereinbefore described with reference to the accompanying drawings.
12. Any novel and inventive feature or combination of features as hereinbefore described.