GB1571380A - Plug and socket connection - Google Patents

Description

(54) PLUG AND SOCKET CONNECTION (71) We, RAYCHEM LIMITED, a British Company, of Moor House, London Wall, London EC2Y 5HP, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to connectors, especially electrical connectors, and methods for their manufacture and use.

In British Patent Specification No.

1,504,704, to which this application is an application for a Patent of Addition, there is described and claimed a connector which comprises a first connector member at least part of which is substantially non-resilient (as hereinafter defined) and deformable and a second member made from a memory metal, the arrangement of said members being such that a temperature below the transition temperature of the memory metal the non-resilient deformable part of the first member and the second member can be deformed from their existing configuration and that when the connector is then raised to a temperature above the transition temperature. the recovery of the second member towards its original configuration will force the deformable part of the first connector member back towards its original configuration. A preferred form of connector according to Patent Specification No. 1,504,704 comprises a substantially non-resilient socket member with a deformable recess portion at one end and a heat-recoverable metal ring which is positioned about the deformable recess portion and which, on recovery, shrinks and forces the socket member into firm engagement with a substrate such as a connector pin positioned within the recess.

The heat-recoverable metal ring or band is made from a so-called "memory metal".

As is known, "memory metals" are alloys which exhibit a martensitic transition when passing through a narrow temperature range and which can be used to make heatrecoverable articles. Such alloys and uses for them are described, for example, in the book "Shape Memory Effects in Alloys" (Jeff Parkins, Plenum Press, New York and London, 1975). Amongst suitable alloys for use in the invention described in Patent Specification No. 1,504,704 there may be mentioned various alloys of titanium and nickel described, for example, in U.S.

Patent Nos. 3,174,851, 3,351,463, 3,753,700, 3,759,552, British Patent Nos.

1,327,441 and 1,337,442 and NASA Publi cation SP 110, "55-Nitinol-The Alloy with a Memory, etc." (U.S. Government Printing Office, Washington, D.C. 1972). The prop erty of heat-recoverability has not, however, been solely confined to such titanium-nickel alloys. Thus, for example, various beta-brass alloys have been demonstrated to exhibit this property in e.g. N. Nakanishi et al, Scripta Metallurgica 5, 433-440 (Pergamon Press 1971) and such materials may be doped to lower their transition temperatures to cryogenic regimes by known techniques.

Similarly, 304 stainless steels have been shown to enjoy such characteristics, E.

Enamietal, id at pp.663-68.

In general these metals have a transition temperature within the range of from -196"C to +135"C, especially from -196"C to -700C (this being the lowest temperature they are liable to encounter during everyday use), and thus may be brought into their martensitic state by immersion in liquid nit rogen. However, more recently, it has been found possible to "precondition" memory metals so as transiently to raise their transi tion temperature. This enables the articles made from such alloys to be kept at room temperature prior to use, when they can be recovered by heating. Such preconditioning methods, which eliminate the need for liquid nitrogen during storage and transportation, are described, for example, in British Patent Application No. 3940/76 (Serial No.

1558194) and U.S. Patent No.4,095,999.

In the connectors described and claimed in Patent Specification No. 1,504,704, the socket member and the metal band or ring are deformed simultaneously in order to bring the connector into its operative position with the metal band or ring in its heatrecoverable form. The deforming expansion may be performed by first bringing the connector to a temperature at which the memory metal exists in its martensitic state (this being conveniently effected by immersion in, or spraying with, liquid nitrogen) and then forcing a suitably sized mandrel indo the recess portion of the socket, which is, in general, longitudinally slotted to facilitate expansion. In some cases it may be appropriate to use the substrate itself to effect the expansion but the forces involved are considerable and may lead to damage of other parts of the substrate. The thus deformed connector can if desired be kept at room temperature by inserting a keeper into the recess portion to prevent recovery or may be stored in liquid nitrogen. In use the connector is applied to the substrate, for example a connector pin, in its low-temperature state and is then allowed to warm to make the connection. An advantage of such a connector is that it requires no force to posi tion the substrate within the recess portion, i.e. it is a "zero insertion force" device. A further advantage is that no heating is required. It is therefore especially suitable for use with fragile and temperaturesensitive substrates. An especially preferred use for such a connector is in the connection of the multiple conductor cores of a power cable to the multiple pins of a bulkhead feedthrough device of the type used in power stations, ships and aircraft. In such an application the socket member is attached to the conductor core by conventional methods, for example by soldering or crimping, and may be provided with a recess portion at its other end for this purpose. The connection to a pin is then carried out as described above.

The present invention is based on our observation that in some cases, especially when a number of connections are to be made at the same time, it is disadvantageous to form the connectors, as in Patent Specification No. 1,504,704, by simultaneous deformation of the socket member and the memory metal ring. Furthermore, we have found that in many cases it will be desirable not to deform the socket member at all prior to connection.

The present invention accordingly provides a method of making a connector comprising a socket member having at least one substantially non-resilient (as hereinafter defined) deformable terminal recess portion and a heat-recoverable metal member positioned about said recess portion and adapted to deform said recess portion upon recovery, which method comprises the steps of (a) deforming a member made of a memory metal so as io make it heat-recoverable; and (b) positioning said deformed memory metal member about the deformable recess portion of said socket member.

The present invention also provides a connector made by the above method and, more especially, a connector comprising a socket member having at least one undeformed but substantially non-resilient (as hereinafter defined) deformable terminal recess portion and a heat-recoverable metal member positioned about said recess portion.

The present invention is especially applicable to the connection of a plurality of conductors from a multi-core power cable to the pins of a bulkhead feedthrough device and is even more especially suited for use in a method of making such a plurality of connections as described below.

A multi-core cable is stripped to expose about 5 inches of each of its fourteen insulated cores and each of the insulated cores is then stripped to expose about 1 inch of bare conductor. The stripped cores are then positioned approximately in a desired arrangement, preferably by using a spacer disc having fourteen apertures corresponding to the pins of the bulkhead device.

Before or after this operation each conductor is attached to a socket member. This may be done, for example, by crimping or soldering, the socket member preferably being with a terminal recess portion for this purpose.

With the conductors and their attached socket members in position in the spacer disc the socket members are then arranged with their deformable recess portions positioned loosely over the pins of the bulkhead device. This ensures an accurate arrangement of the conductors. Cotton wool is then stuffed between and around the sockets and is impregnated with water and liquid nitrogen which freezes solid to produce a rigid structure. Alternatively, any other material which can be frozen solid can be used to fix the conductors and sockets accurately in position, for example polyurethane foam may be used which becomes brittle and rigid on the application of liquid nitrogen. Advantageously, a continuous band of material, such as a strip of felt, is arranged around the outer perimeter of the assembly so as to ensure that the outermost conductors will not become detached from the frozen structure. This strip of material is itself frozen solid during the freezing operation. It will be appreciated that other coolants or methods of cooling can be used in order to produce the frozen structure, the term "freezing" as used herein meaning that the temperature of the assembly is reduced to 0 C or lower.

As a result of this operation, there is obtained a rigid structure in which the conductors and their sockets are firmly held in position in the desired arrangement. This structure is then removed from the pins, at which stage the spacer disc may, if required, be removed. Pre-expanded heatrecoverable metal rings are then placed over the terminal deformable recess portions of the socket members. The installation of the rings takes only a short time, especially if a suitably designed installation tool is used, but the recovery of the rings is, in any case, restrained by the coldness of the frozen structure and thus premature shrinkage of the rings is avoided. The frozen structure with the rings in position about the socket members is now reconnected to the pins of the bulkhead device and the whole assembly is allowed to warm whereupon the rings shrink to form the desired connections.

After connection, the frozen material, for example the cotton wool or the polyurethane foam, may now be readily removed if desired.

A similar method could, of course, be used to form a splice between multi-core cables. In such a case, for example, pins could be attached in a conventional manner to one set of core conductors and socket members in accordance with the present invention could be attached to the other set.

One or, preferably both of the sets could then be frozen in position and pre-expanded memory metal rings could be applied to the socket members. The pins could then be inserted into the socket members and the resultant assembly allowed to warm to effect recovery and connection. It will be appreciated that whilst such a method can in some cases be used with connectors of the type described and claimed in Patent Specification 1,504,704 it will, in most cases, be inconvenient to use those connectors which require simultaneous deformation of the socket member and the memory metal ring.

To expand the memory metal rings in situ on the frozen structure would take more time and thus might lead to premature recovery of the rings and there would also be a considerable danger of damage to the frozen structure. However, when the memory metals rings are applied in a pre-expanded state to the socket members held in the frozen structure, the whole operation can be carried out rapidly without danger of premature recovery or damage to the assembly.

Thus it will be appreciated that the present invention shows considerable advantages as compared with the invention described and claimed in Patent Specification 1,504,704, especially when used in conjunction with the method of fixing a plurality of socket members in a predetermined arrangement, as described above. It will also be appreciated that there will be other applications, especially those involving the formation of a plurality of connections, in which the use of connectors made in accordance with the present invention will prove to be especially advantageous.

Another advantage of the present invention is that it is possible to form the connectors in situ immediately prior to making the connection. That is to say, in many applications it will not be necessary to make and store the connectors prior to their actual use. This is another advantage compared with the connectors described and claimed in Patent Specification 1,504,704 where the general need for mandrel expansion often precludes the possibility of forming the simultaneously deformed connectors on site.

Thus the present invention further provides a method making a connection with at least one substrate which comprises the steps of (a) deforming a member made of a memory metal so as to make it heat-recoverable; (b) positioning said deformed memory metal member substantiallv non-resilient (as hereinafter defined) about a deformable recess portion of a socket member; (c) inserting the substrate into said deformable recess portion; and (d) allowing the resulting assembly. to warm so that the heat-recoverable metal member recovers and forces the deformable recess portion into firm engagement with the substrate.

It will be seen from the above discussion that such a method is especially applicable to the formation of a plurality of connections in a single stage operation.

A further advantage of the present invention as compared with the invention described and claimed in Patent Specification 1,504,704 is that because the socket member need not be deformed together with the heat-recoverable metal member, the possibility of damage to the socket member before the connection operation is substantially reduced. This is especially advantageous where the socket member has to be made from a relatively weak material, and/or the recessed portion of the socket member is provided with a plurality of longitudinal slots and is thus substantially weakened in that area.

It will, of course, be understood that the heat-recoverable member, the socket member and the substrate should be so contoured that a secure connection is made.

Thus, when the substrate is in the form of a round pin, preferably the socket member has a tubular recess of slightly larger diameter than the pin and the heat-recoverable member is in the form of a ring of slightly larger diameter than the outside of the socket. Such contouring can include gradual or stepwise changes in the cross-section of one or more of the socket member, heatrecoverable member and substrate, so as to enhance engagement upon recovery. For example the pin may be cut away at its terminal portion to provide a seat onto which the socket member is deformed by the recovery of the heat-recoverable sleeve or ring. Alternatively, the pin may, for example, be provided with an annular groove the width of which corresponds to that of the heat-recoverable sleeve or ring. Similarly, it may in some applications be advantageous to provide the socket member with a suitably contoured portion to facilitate positioning of the heat-recoverable metal sleeve or ring. This contoured portion may, for example, be a simple annular shoulder against which the recoverable sleeve or ring abuts to ensure correct positioning.

The heat-recoverable sleeve or ring, which may be split or continuous, may be made from any suitable memory metal. In many applications it can advantageously be made from a nickel titanium alloy. However, in other applications, especially where it is necessary for the sleeve or ring to have good electrical properties, it may be convenient to make it from another alloy, especially a brass. The substrate, e.g. the pin, and the socket member may similarly be formed of any suitable material, depending upon the application concerned. For example when a good electrical connection is required it may be advantageous for both the pin and socket member to be made from copper. In other applications it may be appropriate to form at least the socket member from aluminium. In all cases, it will generally be advantageous to choose the materials of the socket member and the substrate so that galling occurs between their contacting surfaces.

Various embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a cross-section through a bulkhead feedthrough device; Figure 2 is an end view of the device of Figure 1; Figure 3 is a side view of another bulkhead feedthrough device; Figure 4 is an end view of the device of Figure 3; Figure 5 is a section through a socket member; Figure 6 is an end view of the socket member of Figure 5; Figure 7 shows a spacer disc; Figure 8 shows the conductors of a multicore cable positioned within the spacer disc of Figure 7; Figure 9 shcws the assembly of Figure 8 loosely positioIIed on the bulkhead feedthrough device of Figures 3 and 4; Figure 10 is a further view, partly in cross-section, similar to Figure 9; Figure 11 shows the assembly of Figure 10 after removal from the bulkhead feedthrough device; Figure 12 shows the assembly of Figure 11 with heat-recoverable metal rings in position about the socket members; Figure 13 shows the assembly of Figure 12 repositioned on the bulkhead feedthrough device, and Figure 14 is a cross-section showing a connector in accordance with the present invention positioned about a connector pin.

Referring now to the drawings, there is shown in Figure 1 and 2 a bulkhead feedthrough device 1 having fourteen connector pins indicated generally by the reference numeral 2 which are held in and pass through a moulded body portion 3. The arrangement of the pins 2 is clearly shown in Figure 2. Typically the pins will be made from high conductivity copper and the moulded body portion 3 will be made from a tough plastics material such as a polyarylene, although in some applications it may be made of a more fragile material such as glass.

In Figures 3 and 4 there is shown a somewhat similar bulkhead feedthrough device 4 provided with three connector pins 5 held within and passing through a moulded body 6.

Bulkhead feedthrough devices of the type shown in Figures 1 to 4 are commonly positioned in the dividing walls of power stations and in the walls and partitions of naval and aerospace vehicles.

Figures 5 and 6 show a socket member 7 suitable for use in the present invention.

The socket member 7 is provided with two recessed terminal portions 8 and 9 separated by a central solid body portion 10.

Recess portion 8 is adapted to receive, and form a crimped joint to, a conductor from a multicore power cable. Recess portion 9, which is provided with four longitudinal slots 11, is adapted to receive a pin 5 from the bulkhead feedthrough device shown in Figures 3 and 4. The recess portion 9 is deformable and has been cut away to provide a seat 12 and a shoulder 13. A heatrecoverable metal ring can be placed on this seat and will abut the shoulder 13 to ensure correct positioning.

Figure 7 shows a spacer disc 14 having three apertures 15 arranged to correspond with the arrangement of the pins 5 of the bulkhead feedthrough device of Figures 3 and 4.

Figure 8 shows an assembly which has been produced by crimping three socket members 7 onto the conductors of the insulated cores 16 of a three-core power cable 17. the conductors with their attached socket members then being positioned in the spacer disc 14.

As is shown in Figure 9 the assembly so produced is then positioned loosely on the pins 5 of bulkhead feedthrough device 4 which is in position in a wall 18. By positioning the socket members 7 on the pins 5 a correct arrangement of the socket members is ensured.

As is shown in Figure 10, cotton wool 19, felt or another absorbent material is now stuffed between and arranged around the socket members 7, the spacer disc 14 acting as a back-stop to help this operation. A continuous band of felt 20 is wound around the cotton wool 19 and both materials are then impregnated with water and liquid nitrogen.

The assembly promptly freezes to form a rigid structure which, as is shown in Figure 11, is then immediately removed from the bulkhead feedthrough device 4.

If desired the spacer disc 14 can now be removed and, as is shown in Figure 12, preexpanded heat-recoverable metal rings 21 are immediately placed in position about the deformable recess portions 9 of socket members 7. A suitable installation tool may be used, especially in cases where the number of sockets is large, for example, in the application of the invention to the bulkhead feedthrough device of Figures 1 and 2.

The coldness of the assembly prevents premature recovery of the heat-recoverable rings 21, but the assembly produced in Figure 12 is immediately repositioned on the bulkhead feedthrough device 4, as is shown in Figure 13, whereupon it warms up and the rings 21 shrink to force the socket members 7 into firm engagement with the pins 5 and thus make a secure connection. If desired the felt 20 and cotton wool 19 may now be removed.

It will be appreciated that a similar operation can now if necessary be performed on the other side of the bulkhead feedthrough device 4 in order to complete the operation.

Finally, in Figure 14 there is shown part of a second connector for use in the present invention positioned around a pin connector. As can be seen, the connector according to the present invention is provided with a deformable recess portion 22 on which sits a heat-recoverable metal band 23. The pin 24 is provided with an annular groove 25, the arrangement being such that the band 23 is positioned above groove 25 so that on recovery the deformable recess portion 22 is forced into that groove to form a secure engagement.

It will be appreciated from the above description that the present invention is especially applicable to the formation of a plurality of connections, e.g. from 2 to 20 connections, usually in a single stage operation, in situations where the complexity size and close proximity of the components concerned would preclude the use of other methods. For example, in the bulkhead feedthrough device shown in Figures 1 and 2 the outer diameter of the moulded body 3 will typically be about 80 mm and the pins 2 will, in such a case, generally have a diameter of about 7mm, the distance between the centres of the pins being from about 9 to 10 mm and the exposed lengths of the pins being about 20 mm.

However, the present invention is, of course, equally applicable in circumstances in which the demands of size and space are not so great but, where, for example, other factors preclude the use of conventional methods. One example of such an application is in the attachment of conductors to the pins of hermetically sealed feedthrough devices. In these devices the pins, which, for example, may be made from nickel/iron alloy, are commonly mounted in glass. The fragility of such devices makes the use of the zero insertion force connectors of the present invention especially advantageous.

By "substantially non-resilient" there is herein meant that the deformable member unlike the resilient member described in tJ.S. Patent No. 3,740,839) is not sufficiently resilient that when the recoverable member is cooled below the temperature at which its transition to martensite occurs, it will by its own resilience deform the recoverable member.

WHAT WE CLAIM IS: 1. A method of making a connector comprising a socket member having at least one substantially non-resilient (as hereinbefore defined) deformable terminal recess portion and a heat-recoverable metal member positioned about said recess portion and adapted to deform said recess portion upon recovery, which method comprises the steps of (a) deforming a member made of a memory metal so as to make it heat-recoverable, and (b) positioning said deformed memory metal member about the deformable recess portion of said socket member.

2. A method as claimed in claim 1, wherein the socket member is contoured to facilitate correct positioning of the memory metal member.

3. A method as claimed in claim 2,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (34)

**WARNING** start of CLMS field may overlap end of DESC **. Figure 7 shows a spacer disc 14 having three apertures 15 arranged to correspond with the arrangement of the pins 5 of the bulkhead feedthrough device of Figures 3 and 4. Figure 8 shows an assembly which has been produced by crimping three socket members 7 onto the conductors of the insulated cores 16 of a three-core power cable 17. the conductors with their attached socket members then being positioned in the spacer disc 14. As is shown in Figure 9 the assembly so produced is then positioned loosely on the pins 5 of bulkhead feedthrough device 4 which is in position in a wall 18. By positioning the socket members 7 on the pins 5 a correct arrangement of the socket members is ensured. As is shown in Figure 10, cotton wool 19, felt or another absorbent material is now stuffed between and arranged around the socket members 7, the spacer disc 14 acting as a back-stop to help this operation. A continuous band of felt 20 is wound around the cotton wool 19 and both materials are then impregnated with water and liquid nitrogen. The assembly promptly freezes to form a rigid structure which, as is shown in Figure 11, is then immediately removed from the bulkhead feedthrough device 4. If desired the spacer disc 14 can now be removed and, as is shown in Figure 12, preexpanded heat-recoverable metal rings 21 are immediately placed in position about the deformable recess portions 9 of socket members 7. A suitable installation tool may be used, especially in cases where the number of sockets is large, for example, in the application of the invention to the bulkhead feedthrough device of Figures 1 and 2. The coldness of the assembly prevents premature recovery of the heat-recoverable rings 21, but the assembly produced in Figure 12 is immediately repositioned on the bulkhead feedthrough device 4, as is shown in Figure 13, whereupon it warms up and the rings 21 shrink to force the socket members 7 into firm engagement with the pins 5 and thus make a secure connection. If desired the felt 20 and cotton wool 19 may now be removed. It will be appreciated that a similar operation can now if necessary be performed on the other side of the bulkhead feedthrough device 4 in order to complete the operation. Finally, in Figure 14 there is shown part of a second connector for use in the present invention positioned around a pin connector. As can be seen, the connector according to the present invention is provided with a deformable recess portion 22 on which sits a heat-recoverable metal band 23. The pin 24 is provided with an annular groove 25, the arrangement being such that the band 23 is positioned above groove 25 so that on recovery the deformable recess portion 22 is forced into that groove to form a secure engagement. It will be appreciated from the above description that the present invention is especially applicable to the formation of a plurality of connections, e.g. from 2 to 20 connections, usually in a single stage operation, in situations where the complexity size and close proximity of the components concerned would preclude the use of other methods. For example, in the bulkhead feedthrough device shown in Figures 1 and 2 the outer diameter of the moulded body 3 will typically be about 80 mm and the pins 2 will, in such a case, generally have a diameter of about 7mm, the distance between the centres of the pins being from about 9 to 10 mm and the exposed lengths of the pins being about 20 mm. However, the present invention is, of course, equally applicable in circumstances in which the demands of size and space are not so great but, where, for example, other factors preclude the use of conventional methods. One example of such an application is in the attachment of conductors to the pins of hermetically sealed feedthrough devices. In these devices the pins, which, for example, may be made from nickel/iron alloy, are commonly mounted in glass. The fragility of such devices makes the use of the zero insertion force connectors of the present invention especially advantageous. By "substantially non-resilient" there is herein meant that the deformable member unlike the resilient member described in tJ.S. Patent No. 3,740,839) is not sufficiently resilient that when the recoverable member is cooled below the temperature at which its transition to martensite occurs, it will by its own resilience deform the recoverable member. WHAT WE CLAIM IS:

1. A method of making a connector comprising a socket member having at least one substantially non-resilient (as hereinbefore defined) deformable terminal recess portion and a heat-recoverable metal member positioned about said recess portion and adapted to deform said recess portion upon recovery, which method comprises the steps of (a) deforming a member made of a memory metal so as to make it heat-recoverable, and (b) positioning said deformed memory metal member about the deformable recess portion of said socket member.

2. A method as claimed in claim 1, wherein the socket member is contoured to facilitate correct positioning of the memory metal member.

3. A method as claimed in claim 2,

wherein the external surface of the socket member at the terminal recess portion is cut away to provide a seat for the memory metal member and a shoulder against which it can abut.

4. A method as claimed in any one of claims 1 to 3, wherein the socket member is attached to a conductor.

5. A method as claimed in claim 4, wherein the socket member is provided with a second terminal recess portion for attachment to a conductor.

6. A method as claimed in claim 5, wherein the socket member is a substantially cylindrical member having a recess at each end and a solid central portion separating said recesses.

7. A method as claimed in any one of claims 1 to 6, wherein the or each terminal recess portion is longitudinally slotted to facilitate its deformation.

8. A method as claimed in any one of claims 1 to 7, wherein the heat-recoverable metal member is a continuous band or ring.

9. A method as claimed in any one of claims 1 to 8, wherein the heat-recoverable metal member is made from an alloy of nickel and titanium or a brass.

10. A method of making a connection with at least one substrate which comprises the steps of (a) deforming a member made of a memory metal so as to make it heat-recoverable, (b) positioning said deformed memory metal member about a substantially nonresilient (as hereinbefore defined) deformable recess portion of a socket member.

(c) inserting the substrate into said deformable recess portion, and (d) allowing the resulting assembly to warm so that the heat-recoverable metal member recovers and forces the deformable recess portion into firm engagement with the substrate.

11. A method as claimed in claim 10, wherein the socket member is contoured to facilitate correct positioning of the memory metal member.

12. A method as claimed in claim 11, wherein the external surface of the socket member at the terminal recess portion is cut away to provide a seat for the memory metal member and a shoulder against which it can abut.

13. A method as claimed in any one of claims 10 to 12, wherein the socket member is attached to a conductor.

14. A method as claimed in claim 13, wherein the socket member is provided with a second terminal recess portion for attachment to a conductor.

15. A method as claimed in claim 14, wherein the socket member is a substantially cylindrical member having a recess at each end and a solid central portion separating said recesses.

16. A method as claimed in any one of claims 10 to 15, wherein the or each terminal recess portion is longitudinally slotted to facilitate its deformation.

17. A method as claimed in any one of claims 10 to 16, wherein the heatrecoverable metal member is a continuous band or ring.

18. A method as claimed in any one of claims 10 to 17, wherein the heatrecoverable metal member is made of an alloy of nickel and titanium or a brass.

19. A method as claimed in any one of claims 10 to 18, wherein a plurality of connections are made in a single operation in which a plurality of substrates are inserted into the respective deformable recess portions of a plurality of socket members and the resulting plurality of assembled substrates and socket members (with their heatrecoverable members in posltion) is allowed to warm so as simultaneously to effect the plurality of connections.

20. A method as claimed in claim 19, wherein from 2 to 20 connections are made.

21. A method as claimed in claim 19 or claim 20, wherein the substrates are the pins of a feedthrough device and the socket members are attached to the conductors of the insulated cores of a multicore cable.

22. A method as claimed in claim 21, wherein the pins are mounted in a fragile material such as glass.

23. A method as claimed in any one of claims 19 to 22, wherein the plurality of socket members is fixed in a desired predetermined arrangement by surrounding them with a soft pliable material which can be frozen to make it solid and the material is then frozen to form a solid structure.

24. A method as claimed in claim 23, wherein the socket members are each attached to a conductor prior to being fixed in the frozen structure.

25. A method as claimed in claim 23 or claim 24, wherein the socket members are placed approximately in the desired arrangement by means of a spacer member prior to the application of the relatively soft pliable material.

26. A method as claimed in any one of claims 23 to 25, wherein the plurality of socket members is brought exactly into the desired arrangement by positioning them about the plurality of substrates prior to the freezing operation.

27. A method as claimed in any one of claims 23 to 26, wherein the soft pliable material is cotton wool, felt or a similar absorbent material which is impregnated with water and liquid nitrogen to cause it to freeze.

28. A method as claimed in any one of claims 23 to 26, wherein the soft pliable material is polyurethane foam which is treated with liquid nitrogen to cause it to become brittle and rigid.

29. A method as claimed in any one of claims 23 to 28, wherein a continuous band of material is arranged around the outer perimeter of the soft pliable material.

30. A connector comprising a socket member having at least one undeformed but substantially non-resilient (as hereinbefore defined) deformable terminal recess portion and a heat-recoverable metal member positioned about said recess portion.

31. A connector as claimed in claim 30, whenever made by a method as claimed in any one of claims 1 to 9.

32. A method as claimed in claim 1, carried out substantially as described herein with reference to, and as illustrated in, the accompanying drawings.

33. A method as claimed in claim 10, carried out substantially as described herein with reference to, and as illustrated in, the accompanying drawings.

34. A connector as claimed in claim 30, substantially as described herein with reference to, and as illustrated in, the accompanying drawings.