WO2003103103A1

WO2003103103A1 - Cable connector and locking shroud

Info

Publication number: WO2003103103A1
Application number: PCT/GB2003/002320
Authority: WO
Inventors: Mark Ian Mckinnie; Craig Stuart Hislop
Original assignee: W L Gore & Associates (Uk) Ltd.
Priority date: 2002-06-01
Filing date: 2003-05-29
Publication date: 2003-12-11
Also published as: GB0212852D0; AU2003241018A1

Abstract

A cable connector assembly (10) includes a threaded connector part (12) and a coupling part (20), comprising a threaded nut (22) rotatable on a cable holder (26). The nut (22) engages with the connector part (12). The cable holder (26) includes a profiled external face (32) defining a pair of flats. A locking shroud (34) including a number of internal elastomeric O-rings (38) may be passed over the cable holder (26) and nut (22), whereupon the O-rings (38) engage with the outer surface of the nut (22). The shroud (34) further includes a profiled portion (40) which engages with the flats of the external face (32) of the cable holder (26). The combination of the profile (40) and the O-rings (38) serve to hold the nut (22) stationary relative to the cable holder (26), and so prevent disassembly of the connector assembly (10).

Description

CABLE CONNECTOR AND LOCKING SHROUD

The present invention relates to an electrical connector assembly, and in particular a connector assembly having lockable means to prevent loosening of the connector.

Many connector assemblies include a coupling part which is rotatable with respect to the other connector parts about an axis. This rotatable part is often a coupling nut adapted to be coupled to an externally threaded mating connector. Such assemblies are commonly used in making electrical connections between cables and the like. The coupling part may be rotatably mounted on an inner cable holder fixed to an end of a cable which passes through the coupling part to engage with a cable terminal of the mating connector. To allow tightening of the threads of the coupling part and mating connector, the coupling part and cable holder are relatively rotatable, since the cable which passes through the cable holder is often non- rotatable. In particular applications, it may be desirable to be able to lock the coupling part with respect to the other connector parts, to prevent or restrict unwanted rotation and loosening of the connector. For example, where the connector is to be exposed to vibrations or other shocks, without locking of the coupling part the connector may work itself loose, leading to a loss of connection. Further, relative rotation between the coupling part and the cable holder may disrupt the electrical connection leading to noise or loss of signal on the cable.

To overcome this, one solution is to provide a ratchet and tooth arrangement to 'hold the coupling part and connector part together at a predetermined position with a predetermined contact force. However, such an arrangement may not be suitable for all types of connector assembly, and does not easily permit variation of the contact force if necessary. An alternative construction provides a locking shroud which fits over the coupling part and engages with the mating part of the connector. To prevent relative rotation of the coupling part and the mating part, splines are provided on the coupling part and the mating part, with corresponding splines formed on the inner surface of the locking shroud. The locking shroud thus engages with the coupling part and the mating part, while the interengaging splines prevent relative rotation of the shroud and mating part, and hence also of the coupling part. The connector may thus be secured against unwanted rotation.

However, in order to fit the shroud over the coupling part and the mating part, the splines on the components^' must be aligned with one another. This can be a delicate operation, and can greatly complicate the fitting and installation of such connectors, as the user must ensure that all parts of the connector are aligned, perhaps by making many slight adjustments to each of the components, before the locking shroud may be fitted. This can be particularly difficult when the connector is to be installed in a relatively inaccessible location, or in an awkward alignment, which restricts the accessibility of the connector to fitting tools.

Furthermore, for a number of high-specification applications, the contact force between the parts of the electrical connections must be carefully determined; this is typically achieved by reference to the torque which must be applied to the coupling part to obtain the desired contact force. The torque may be restricted by making up the connector using a torque wrench or similar tool, which allows only torque up to a predetermined value to be applied to a fitting. Once this has been done, however, if it is then necessary to adjust the alignment of the parts of the connector to ensure alignment of splines, then this will alter the make-up torque of the components. This is clearly undesirable if a defined torque is necessary or desirable.

It is among the objects of^• embodiments of the present invention to obviate or alleviate these and other disadvantages of known locking connectors.

According to a first aspect of the present invention, there is provided a connector assembly comprising: a coupling part comprising an engagement member for engaging with a corresponding connector part, and a cable holder, the cable holder being rotatable relative to the engagement member, and having a profile portion; and a locking shroud having a through bore, the shroud comprising a resilient member located in the bore for engaging with the engagement member, and a profile portion for engaging with the corresponding profile portion of the cable holder; wherein when the resilient member is engaged with the engagement member, and the locking shroud profile portion is engaged with the cable holder profile portion, relative rotation of the engagement member and the cable holder is restricted or prevented.

The present invention thus provides a locking shroud which engages with the engagement member by means of a resilient member, rather than splines or the like profiles, and which holds the engagement member locked with respect to the cable holder. Since the cable held by the cable holder may be securely held in place at a location away from the cable connector, this will tend to prevent the cable holder from rotating, while the locking shroud serves to prevent the engagement member from rotating. Vibration will therefore be less likely to lead to relative rotation of the parts . of the connector, such that undesired loosening or movement of the cable connection will be less likely. Further, it is not essential to hold the engagement member securely with respect to the connector part, since the whole of the connector assembly is secured by virtue of the cable. It is therefore possible to fit the shroud and coupling part to a pre-existing connector part. The resilient member is deformable, and may engage with the engagement member in any of a number of orientations, thereby avoiding the need for precise alignment of the engagement member and the cable holder; for example, as would be the case if splines were used. Installation and locking of the connector is thus greatly simplified, compared with conventional locking connectors, and it is possible for a user to provide a desired torque to the connector before fitting the locking shroud without the need to alter the torque to allow the shroud to be fitted.

Preferably the connector assembly further comprises a connector part for engaging with the engagement member of the coupling part.

Preferably the assembly further comprises a cable mounted to the cable holder. The cable may be an electrical, fibre optic, or other cable. The cable may be coaxial, twinaxial, or indeed may take any form. Preferably the assembly further comprises means for securing the cable at a location other than at the cable holder against unwanted movement; this may comprise cable clips, adhesive tape or the like, or any suitable means. Preferably the resilient member is polymeric; more preferably elastomeric.

Preferably the engagement member comprises a screw thread, which allows the connector part and coupling part to be engaged or disengaged on relative rotation in an appropriate direction.

Preferably the cable holder comprises means for permitting an electrical connection to be formed between electrical conductors held by the cable holder and the connector part. The cable holder may include a male or female member which engages with a corresponding female or male member provided on the connector part.

Preferably the engagement member has an external profile of conventional shape, suitable for engagement with a conventional tool. For example, the engagement member may have an external profile of the shape of a nut, or generally hexagonal. This allows the engagement member to be tightened by means of a conventional tool, such as a torque wrench. Preferably the engagement member has an external profile having generally straight sides meeting at edges defining the maximum diameter described by the engagement member. The presence of edges allows the engagement member to engage more firmly with the resilient member of the locking shroud.

Preferably the respective profile portions of the cable holder and the locking shroud are arranged coaxially with the bore of the locking shroud. This ensures that the profile portions are aligned with one another as the bore of the shroud is aligned with the cable holder and engagement member, so removing the requirement for additional alignment of the various connector components.

Preferably the profile portions of the cable holder and locking shroud are engageable in multiple orientations; this permits the profiles to be engaged without requiring careful alignment of the connector components in only one possible position. This may be of assistance when the locking shroud is to be fitted in a relatively inaccessible location, where the user may be unable to precisely determine the relative alignment of the components. Preferably the locking shroud bears a knurled or otherwise textured outer surface; this provides a secure grip for a user, allowing the shroud to be manipulated manually without the need for specialised tools.

Conveniently the resilient member may comprise one or more O-rings. Preferably however the resilient member comprises an inner resilient shroud disposed within the locking shroud. The resilient member is preferably bonded or otherwise secured to the bore of the locking shroud. The resilient member need not be substantially continuously disposed around the interior of the bore, although it will be appreciated that this may restrict the range of orientations in which the locking shroud may be engaged with the engagement member.

In certain embodiments of the invention, the locking shroud and the resilient member may comprise a side opening along the length of the locking shroud, providing communication between the bore of the shroud and the exterior of the shroud. This allows the locking shroud to be placed onto a cable, electrical conductor, or the like via the side opening, rather than by feeding the cable through the bore of the shroud. This may greatly simplify fitting of the locking shroud, since this may be done after a cable has been fitted and connected, without the need to disconnect one end of the cable. Where a cable is otherwise secured in position, this feature is particularly useful to allow the shroud to be fitted onto a pre-existing cable. Preferably the side opening of the resilient member is relatively narrow; the resilient member may deform to permit a cable to be passed therethrough without providing a large opening whereby the cable may easily pass back out of the resilient member.

The components of the connector may be made from any suitable material or materials; metal or polymers are acceptable. A preferred material for the shroud is PEEK (poly (ether-etherketone) ) , since this provides strength, lightness, and corrosion resistance.

According to a second aspect of the present invention, there is provided a locking shroud for a connector, the shroud comprising a through bore, a resilient member located in the bore for engaging with an engagement member of a connector; and a profile portion for engaging with a corresponding profile portion of a cable holder of a connector.

A locking shroud according to the present invention may be used in combination with a specifically provided connector, or may be retrofitted to an existing connector assembly, since the resilient member may engage with engagement members of a range of shapes and configurations.

Conveniently the resilient member may comprise one or more O-rings. Preferably however the resilient member comprises an inner resilient shroud disposed within the locking shroud. The resilient member is preferably bonded or otherwise secured to the bore of the locking shroud. The resilient member need not be substantially continuously disposed around the interior of the bore, although it will be appreciated that this may restrict the range of orientations in which the locking shroud may be engaged with the engagement member .

In certain embodiments of the invention, the locking shroud and the resilient member may comprise a side opening along the length of the locking shroud, providing communication from within the bore of the shroud to the exterior of the shroud. This allows the locking shroud to be placed onto a cable, electrical conductor, or the like via the side opening, rather than by feeding the cable through the bore of the shroud. This may greatly simplify fitting of the locking shroud, since this may be done after a cable has been fitted and connected without the need to disconnect one end of the cable. Preferably the side opening of the resilient member is relatively narrow; the resilient member may deform to permit a cable to be passed therethrough without providing a large opening whereby the cable may pass back out of the resilient member.

These and other aspects of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 illustrates a sectional view of a connector assembly in accordance with a first embodiment of the present invention;

Figure 2 illustrates a transverse sectional view of the connector assembly of Figure 1; and

Figure 3 illustrates a sectional view of a coupling part of a connector according to a second embodiment of the present invention.

Referring to Figures 1 and 2, a connector assembly 10 according to the present invention comprises a connector part 12 having a flange 13 for mounting in a bulkhead, and carrying an electrical cable 14 to a male mating portion

16. The connector part 12 also carries a screw thread 18 for engaging with a coupling part 20. The coupling part 20 comprises an outer nut 22, which carries a cooperating female screw thread portion 24, allowing the coupling and connector parts to be engaged with one another on relative rotation thereof. The outer face of the nut 22 is hexagonal in cross section, allowing the nut 22 to be engaged by means of a conventional tightening tool, such as a torque wrench. Mounted within the outer nut 22 of the coupling part 20, and rotatable relative thereto, is a cable holder 26 which carries an electrical cable 28 to a female mating portion 30, which mates with the cooperating male portion

16 provided on the connector part 12. The cable holder 26 has a profiled external face 32 defining a pair of flats.

The two parts of the electrical cable 14, 28 pass through the coupling and connector parts, and are brought into electrical communication when the coupling and connector parts are engaged. When the coupling and connector parts are engaged to the desired torque, a locking shroud 34 is passed over the cable holder 26 and nut 22 of the coupling part 20. The locking shroud 34 is generally tubular, having an internal through bore 36 within which are mounted a number of elastomeric O-rings 38; these O-rings are brought into an interference fit with the outer edges of the nut 22, so holding the locking shroud 34 in secure engagement with the nut 22. The end of the locking shroud 34 adjacent the cable holder 26 is formed in a shaped profile 40, which fits over and engages the flats 32 of the cable holder 26. This arrangement causes the locking shroud 34 to be held in secure engagement with the cable holder 26. Thus, when the locking shroud 34 is engaged with both the nut 22 and the cable holder 26, these two parts are prevented from relative rotation. Hence any vibration or other interference with the connector will not alter the relative rotation of the nut 22 and cable holder 26. If in use the cable 28 is securely held elsewhere, any vibration will not affect either the holder or the nut, nor be transmitted to the connector part 12. Thus the assembly components cannot inadvertently be released from one another. If the connector assembly 10 is desired to be disassembled, the locking shroud 34 is simply moved away from the nut and cable holder, thereby disengaging the shroud from these parts, and allowing relative rotation once more. The nut may then be rotated relative to the cable holder and connector part to disengage the screw threads 18, 24, allowing the electrical cable 14, 28 to part .

In certain embodiments of the invention, the O-rings 38 may be replaced by an elastomeric shroud covering the inner surface of the locking shroud. Further, the elastomeric and locking shrouds may include side openings to allow the shrouds to be fitted over a cable without passing the shrouds over an end of the cable.

Figure 3 shows a variant coupling part 126 and shroud 134, connected to an electrical cable 128 having a right angle bend therein; this- is known as a box connector. The construction of the coupling part 126 and shroud 134 is similar to that described above, although the shroud 134 is somewhat truncated compared to the shroud 34 of Figure 1, and includes only a pair of O-rings 138.

A number of connectors including a coupling part and shroud in accordance with the present invention were vibration tested, to Mil standard 810D, Method 514.3. The O-rings for each connector were made from Viton 75 durometer (R & M Bearings) , while the shrouds were made either of Vitrex PEEK Grade 450G (PEEK connector) , or of stainless steel 303 passivated to Gore specification 503

(steel connector) . The shroud had an outer diameter of

25.70 mm, a maximum inner diameter of 18.88 mm, and a minimum inner diameter (at the profile portion) of 12.72 mm. The shroud was 14.91 mm in length. Two straight connectors (as illustrated in Figure 1) were tested, one each of PEEK and steel, together with two box connectors (as illustrated in Figure 3), again one each of PEEK and steel. A connector of similar straight construction was also tested without the shroud, to provide an indication of the effect of the shroud. The connectors were tested in accordance with the abovementioned standard under the following conditions, where ^λHz' indicates vibration frequency in hertz, DA' indicates peak to peak displacement amplitude in millimetres, mag' indicates a magnification factor, and g total' indicates the maximum force in multiples of g experienced by the connector.

The results of the tests were as follows

It can be seen that each of the inventive connectors provides an increase in torque after the test compared with a connector with no shroud.

Claims

1. A connector assembly comprising: a coupling part comprising an engagement member for engaging with a corresponding connector part, and a cable holder, the cable holder being rotatable relative to the engagement member, and having a profile portion; and a locking shroud having a through bore, the shroud comprising a resilient member located in the bore for engaging with the engagement member, and a profile portion for engaging with the corresponding profile portion of the cable holder; wherein when the resilient member is engaged with the engagement member, and the profile portion of the locking shroud is engaged with the profile portion of the cable holder, relative rotation of the engagement member and the cable holder is restricted or prevented.

2. The connector assembly of claim 1, wherein the resilient member is polymeric.

3. The connector assembly of claim 1 or claim 2, wherein the resilient member is elastomeric.

4. The connector assembly of any preceding claim, wherein the engagement member comprises a screw thread, which allows the connector and coupling parts to be engaged or disengaged on relative rotation in an appropriate direction.

5. The connector assembly of any preceding claim, further comprising an electrical conductor mounted to the cable holder.

6. The connector assembly of any preceding claim, wherein the cable holder comprises means for permitting an electrical connection to be formed between electrical conductors held by the cable holder and a connector part.

7. The connector assembly of any preceding claim, wherein the engagement member has an external profile of conventional shape, suitable for engagement with a conventional tool.

8. The connector assembly of claim 7, wherein the engagement member has an external profile of the shape of a nut .

9. The connector assembly of any preceding claim, wherein the engagement member has an external profile having generally straight sides meeting at edges defining the maximum diameter described by the engagement member.

10. The connector assembly of any preceding claim, wherein the profile portions of the cable holder and the locking shroud are arranged coaxially with the bore of the locking shroud.

11. The connector assembly of any preceding claim, wherein the profile portions of the cable holder and locking shroud may engage in multiple orientations .

12. The connector assembly of any preceding claim, wherein the locking shroud bears a knurled or otherwise textured outer surface.

13. The connector assembly of any preceding claim, wherein the resilient member comprises one or more O-rings.

14. The connector assembly of any of claims 1 to 12, wherein the resilient member comprises an inner resilient shroud disposed within the locking shroud.

15. The connector assembly of any preceding claim, wherein the locking shroud and the resilient member comprise a side opening along the length of the locking shroud, providing communication between the bore of the shroud and the exterior of the shroud.

16. The connector assembly of claim 15, wherein the side opening of the resilient member is relatively narrow.

17. The connector assembly of any preceding claim, further comprising a connector part.

18. A locking shroud for a connector, the shroud comprising a through bore, a resilient member located in the bore for engaging with an engagement member of a connector; and a profile portion for engaging with a corresponding profile portion of a cable holder of a connector.

19. The locking shroud of claim 18, wherein the resilient member comprises one or more O-rings.

20. The locking shroud of claim 18, wherein the resilient member comprises an inner resilient shroud disposed within the locking shroud.

21. The locking member of any of claims 18 to 20, wherein the locking shroud and the resilient member comprise a side opening along the length of the locking shroud, providing communication from within the bore of the shroud to the exterior of the shroud.