GB2359938A

GB2359938A - Electrical interconnection for screening sleeves

Info

Publication number: GB2359938A
Application number: GB0103981A
Authority: GB
Inventors: Guy James Ashley Dewdney; Alan James Riddell
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 2000-02-29
Filing date: 2001-02-19
Publication date: 2001-09-05
Anticipated expiration: 2021-02-19
Also published as: GB0103981D0; FR2805667A1; GB2359938B; GB0004621D0

Description

2359938 1 ELECTRICAL CONNECTION This invention relates to electrical

connection.

The invention is more particularly concerned with arrangements for making electrical connection between screening sleeves of several wires.

Where a cable includes a wire having a screening sleeve, such as a braid, it is usually necessary to make connection between the braid and a ground plane, such as a connector shell. If the cable includes several individually screened wires it can be more difficult to make connection to the separate screening sleeves. One way in which this is done is by means of several short interconnecting wires electrically interconnecting the screens with one another and with the ground plane. The wires are usually electrically insulated and each has a crimp or solder sleeve at one end, its other end.having the insulation stripped back to expose the conductor. The crimp sleeve on one interconnecting wire is crimped over the screen of one of the signal wires and its free end is inserted within the crimp sleeve of a second interconnecting wire together with the screen of an adjacent signal wire. The free end of the second interconnecting wire is inserted within the crimp sleeve of a fourth interconnecting wire with the screen of a third signal wire, and so on until all the screens are connected with one another via a daisy-chain of interconnected wires. The free end of the last interconnecting wire in the chain is electrically connected to the ground plane, such as the shell of a connector.

2 Although this arrangement can provide a reliable interconnection between the screens and ground, it is time-consuming and awkward because, for every wire, the installer has to thread and retain both the screening sleeve and the free end of an interconnecting wire in the crimp sleeve while it is being crimped. Because it is awkward to hold both the screen and the wire in the sleeve during crimping there is a risk that one of these may not be correctly inserted when the sleeve is crimped.

It is an object of the present invention to provide an alternative arrangement for making electrical connection to screening sleeves.

According to one aspect of the present invention there is provided an arrangement for making connection to screening sleeves on a plurality of wires, the arrangement including a plurality of connection members interconnected with one another by respective lengths of flexible wire attached with the connection members to form a chain, and the connection members being attachable to screening sleeves on the wires so as to interconnect the screening sleeves with one another.

According to another aspect of the present invention there is provided an electrical connection arrangement including a first connection member, a first length of flexible interconnection wire attached at one end with the first connection member and at its opposite end with a second connection member, and a second length of interconnection wire attached at one end with the second connection member, the first and second connection members being attachable to screening sleeves on respective signal wires so as to interconnect the screens with one another.

1 3 According to a third aspect of the present invention there is provided an assembly including a bundle of a plurality of screened signal wires and an interconnection arrangement comprising a plurality of connection members electrically connected with one another in a chain by respective lengths of flexible interconnection wire, the connection members being attached with screens of respective ones of the signal wires so that the interconnecting wires electrically interconnect the screens with one another, and the connection members being attached with the lengths of interconnection wire prior to attachment with the screens.

The connection members may include a crimp sleeve or a solder sleeve. The connection members preferably include a tubular portion, the ends of two of the flexible wires and a screening sleeve being received in the tubular portion. The connection members may include a tail portion. The flexible wires may be attached with the connection members by a weld prior to attachment to the screening sleeves. The screening sleeves preferably extend into the connection members from an end opposite that from which the flexible wires extend. The flexible wires may be bent into a loop between connection members.. One of the flexible wires preferably has one end loose for attachment to a grounding member. Flexible wires at opposite ends of the arrangement may both have one end loose for attachment to a grounding member. An insulating sleeve may embrace each respective connection member and each respective wire so as to retain the connection member against the respective wire.

According to a fourth aspect of the present invention there is provided a method of making electrical connection between screening sleeves on a plurality of signal wires including the steps of providing a connection arrangement comprising a plurality of 4 connection members interconnected with one another in a chain by respective lengths of interconnecting wire attached with respective connection members, and subsequently attaching the connection members to the screening sleeves on respective ones of the signal wires so as electrically to interconnect the screening sleeves with one another.

The method preferably includes the step of attaching an interconnecting wire at one end of the chain to a grounding member and may include the step of attaching interconnecting wires at opposite ends of the chain to a grounding member.

According to a fifth aspect of the present invention there is provided an assembly having screening sleeves interconnected with one another by a method according to the above fourth aspect of the invention.

A cable assembly including a connection arrangement 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 simplified side elevation view of the assembly; Figure 2 is an enlarged cross-sectional side elevation of one connection; Figure 3 is a transverse section along the line III-III of Figure 2; and 4 Figure 4 is a view of the connection arrangement before connection to the cable assembly.

The cable assembly includes a bundle 1 of signal wires 11 to 14 only four of which are shown here for clarity but there could be up to about fifty wires in a bundle. The assembly also includes a connector shell 2, providing a ground plane or member, and a connection arrangement in the form of a chain 3 connecting screens on the wires 11 to 14 with one another and with the connector shell.

Each wire 11 to 14 includes a twisted pair of insulated signal conductors 21 and 22 extending coaxially within a braided screening sleeve 23, which in turn is protected by an outer insulating jacket 24. The jacket 24 is stripped back at the end of the wires 11 to 14 within the shell 2 to expose the signal conductors 21 and 22 and the screening sleeve 23.

The chain 3 has four crimp sleeves 31 to 34 or other connection members, such as solder sleeves, (one for each screened signal wire) connected with one another in series by four insulated interconnecting wires 35 to 38, each wire being about 60mm. long. One end of the first wire 35 is attached to the first crimp sleeve 31 and its other end is attached to the second crimp sleeve 32. The second wire 36 has one end attached to the second crimp sleeve 32 and its other end attached to the third crimp sleeve 33 and so on. The final interconnect wire 38 has one end connected to the final crimp sleeve 34 and has its other end flying or loose, with its insulation stripped back. Each crimp sleeve 31 to 36 is of stainless steel and has a rear tail portion 40 formed at one end of a tubular crimp portion 4 1. The or both interconnecting wires 35 to 38 are attached with the crimp sleeve 31 to 34 by means of a spot 6 weld 42 onto the tail portion 40, with the forward end of the wires extending into the tubular portion 41, which is initially open. The weld 42 is sufficient to keep the crimp sleeves 31 to 34 secured to the wires 35 to 38 during handling but does not provide the main electrical connection. The internal diameter of the tubular portion 41 is sufficient to receive two interconnecting wires and also the screening sleeve 23 of one of the signal wires.

The chain 3 is assembled on the cable assembly in the following manner. Each screening sleeve 23 is twisted to form a short tail. The screen tail 23 from one wire 11 is pushed into the forward end of the first crimp sleeve 31 and this is then crimped tightly about both the screen and the interconnecting wire 35. The crimp forms the main electrical connection between the screen 23 and the interconnecting wire 3 1. The crimped connection is then folded rearwardly alongside the jacket 24 of the signal wire 11 and a short insulating sleeve 50 is slipped over the end of the wire to embrace the crimp sleeve and wire so as to retain the crimp sleeve against the wire. The interconnecting wire 35 is bent in a loop extending rearwardly and the second crimp sleeve 32 is then attached to the screen 23 of the next, adjacent signal wire 12, in the same manner. This crimp sleeve 32 has two interconnecting wires 35 and 36 attached to it so the crimping operation securely connects both these with the screen 23 of the second signal wire 12. This operation is repeated around the cable bundle until each screen 23 is electrically interconnected with one another via the connection chain 3. The fmal interconnecting wire 38 is attached to the connector shell 2 in some conventional manner.

In some applications it may be preferred to have a loose wire at both ends of the chain so that the chain can be connected to the ground plane at both ends. This provides greater 1 7 security and provides a shorter path length to the ground plane for some of the screening sleeves.

The connection chain could be preformed to length with the desired number of crimp sleeves or it could be in a continuous length on a reel in a suitable tool and cut from the length after connection had been made to all the screening sleeves.

If it is necessary to make connection to a ground plane at some distance from the screening sleeves, the connection chain could be extended in length at one or both ends by means of additional lengths of interconnecting wire and crimp sleeves.

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Claims

An arrangement for making connection to screening sleeves on a plurality of wires, wherein the arrangement includes a plurality of connection members interconnected with one another by respective lengths of flexible wire attached with the connection members to form a chain, and wherein the connection members are attachable to screening sleeves on the wires so as to interconnect the screening sleeves with one another.
2. An electrical connection arrangement including a first connection member, a first length of flexible interconnection wire attached at one end with the first connection member and at its opposite end with a second connection member, and a second length of interconnection wire attached at one end with the second connection member, and wherein the first and second connection members are attachable to screening sleeves on respective signal wires so as to interconnect the screens with one another.
An arrangement according to Claim 1 or 2, wherein the connection members include a crimp sleeve.
4. An arrangement according to Claim 1 or 2, wherein the connection members include a solder sleeve.

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5. An arrangement according to any one of the preceding claims, wherein the connection members include a tubular portion, and wherein the ends of two of the flexible wires and a screening sleeve are received in the tubular portion.
6. An arrangement according to any one of the preceding claims, wherein the connection members include a tail portion.
7. An arrangement according to any one of the preceding claims, wherein the flexible wires are attached with the connection members by a weld prior to attachment to the screening sleeves.
8. An arrangement according to any one of the preceding claims, wherein the screening sleeves extend into the connection members from an end opposite that from which the flexible wires extend.
9. An arrangement according to any one of the preceding claims, wherein the flexible wires are bent into a loop between connection members.
10. An arrangement according to any one of the preceding claims, wherein one of the flexible wires has one end loose for attachment to a grounding member.
11.

An arrangement according to Claim 10, wherein flexible wires at opposite ends of the arrangement both have one end loose for attachment to a grounding member.
12. An arrangement substantially as hereinbefore described with reference to the accompanying drawings.
13. An assembly including a bundle of a plurality of screened signal wires and an interconnection arrangement comprising a plurality of connection members electrically connected with one another in a chain by respective lengths of flexible interconnection wire, wherein the connection members are attached with screens of respective ones of the signal wires so that the interconnecting wires electrically interconnect the screens with one another, and wherein the connection members are attached with the lengths of interconnection wire prior to attachment with the screens.
14. An assembly according to Claim 13, wherein the connection members include a crimp sleeve.
15. An assembly according to Claim 13, wherein the connection members include a solder sleeve.
16. An assembly according to any one of Claims 13 to 15, wherein the connection members include a tubular portion, and wherein the ends of two flexible wires and a screening sleeve are received in a tubular portion.
17. An assembly according to any one of the Claims 13 to 16, wherein the connection members include a tail portion.

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18. An assembly according to any one of Claims 13 to 17, wherein the flexible wires are attached with the connection members by a weld prior to attachment to the screening sleeves.
19. An assembly according to any one of Claims 13 to 18, wherein the screening sleeves extend into the connection members from an end opposite that from which the flexible wires extend.
20.

An assembly according to any one of Claims 13 to 19, wherein the flexible wires are bent into a loop between connection members.
21. An assembly according to any one of Claims 13 to 20, wherein one of the flexible wires has one end loose for attachment to a grounding member.
22. An assembly according to Claim 2 1, wherein flexible wires at opposite ends of the interconnection arrangement both have one end loose for attachment to a grounding member.
23. An assembly according to any one of Claims 13 to 22, including an insulating sleeve embracing each respective connection member and each respective wire so as to retain the connection member against the respective wire.
24. An assembly substantially as hereinbefore described with reference to the accompanying drawings.

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25. A method of making electrical connection between screening sleeves on a plurality of signal wires including the steps of providing a connection arrangement comprising a plurality of connection members interconnected with one another in a chain by respective lengths of interconnecting wire attached with respective connection members, and subsequently attaching the connection members to the screening sleeves on respective ones of the signal wires so as electrically to interconnect the screening sleeves with one another.
26.

A method according to Claim 25 including the step of attaching an interconnecting wire at one end of the chain to a grounding member.
27.

A method according to Claim 25 or 26 including the step of attaching interconnecting wires at opposite ends of the chain to a grounding member.
28.

A method of grounding screening sleeves on a plurality of signal wires substantially as hereinbefore described with reference to the accompanying drawings.
29.

An assembly having screening sleeves interconnected with one another by a method according to any one of Claims 25 to 28.
30.

Any novel and inventive feature or combination of features as hereinbefore described.