GB2233838A

GB2233838A - Cable glands

Info

Publication number: GB2233838A
Application number: GB8915113A
Authority: GB
Inventors: Michael Twist; Edward Hand
Original assignee: Hawke Cable Glands Ltd
Current assignee: Hawke Cable Glands Ltd
Priority date: 1989-06-30
Filing date: 1989-06-30
Publication date: 1991-01-16
Also published as: GB8915113D0

Abstract

A cable gland for terminating armoured cable 111 comprises a hollow body 102 having a stepped bore defining a cable passageway having an entry 103a and an exit portion 103b. An abutment shoulder 112a provides a seating for the sheath 111b of the cable 111 and the unsheathed conductors 111a extend with radial clearance from the body 102 for connection as required. A support sleeve 105 slidably mounted in the body carries an earth continuity ring member 106 having flexible tines 106b engageable with the cable sheath 111b and inclined to resist withdrawal of the cable 111 from the gland. The tines directly engage the sheath 111b or pierce surrounding insulation. The sleeve 105 is retained by an end cap 104 holding a seal member 107. The cable 111 is optionally sealed at the exit portion 103b by a filler compound 114 in a removable liner 112 slidably received in the body 102 so as to facilitate dis-assembly of the gland. <IMAGE>

Description

CABLE GLANDS This invention relates to cable glands for terminating cables of the kind comprising a plurality of conductors within a protective outer sheath and in particular, though not exclusively, for terminating metal armoured cables.

In the known cable glands, the end of the cable extends through the gland and has a portion of the sheath removed to expose the conductors which project from the gland for connection to the apparatus or equipment. Various arrangements have been proposed for sealing and/or retaining the sheathed portion of the end of the cable within the gland many of which are of complex construction making fitment and assembly difficult.

Additionally, in certain applications, it is desirable to encapsulate the unsheathed conductors with a filler compound within the gland to prevent ingress of fluid and/or to provide resistance to fire. The provision of such filler compound further complicates the construction of the gland making fitment and assembly more difficult as well as creating problems if the gland later has to be dis-assembled for any reason.

It is an object of the present invention to provide a cable gland of improved construction which is relatively simple to fit and assemble and which can be disassembled if required.

It is another object of the present invention to provide a cable gland which can readily be adapted for encapsulating the unsheathed conductors of the cable with a filler compound within the gland in a simple manner if required.

According to the present invention there is provided a cable gland for the termination of a cable having a plurality of conductors within a protective outer sheath, the gland comprising a hollow body having a through bore defining a passageway for the cable, the bore having at one end an entry portion for the sheathed cable and at the other end an exit portion through which the unsheathed conductors extend with the bore being adapted to receive an optional liner for encapsulation of the unsheathed conductors by a filler compound, a ring member mounted in the entry portion for engagement with the cable sheath, an end cap engageable with the body, and a seal member arranged within the end cap for engagement with the cable sheath.

The invented cable gland with optional liner is of simple construction which can be adapted for use with or without filler compound to encapsulate the unsheathed conductors as required. In this way a complete kit of parts can be provided which the user adapts on site depending on the particular requirements of a given installation for assembly and fitment of the gland with or without the optional liner.

Preferably, the ring member has a plurality of radially inwardly directed flexible tines for resilient engagement with the cable sheath. Where the cable has a protective metal sheath, the ring member is preferably adapted to provide earth continuity between the cable and gland body.

Conveniently, the tines extend towards the exit portion of the bore and are uniformly spaced apart in the circumferential direction. This arrangement facilitates insertion of the cable and provides an even grip around the sheath to resist withdrawal of the cable from the gland.

In one preferred construction, the ring member comprises a cylindrical element with the tines arranged to extend inwardly and axially from one end of the element to the other end.

The preferred number of tines is 8,10 or 12 but any other number of tines may be provided as required.

The inclination of the tines may be selected as required and is preferably in the range 150 to 750 relative to the central longitudinal axis of the element, more preferably in the range 300 to 600 0 with 45 being the optimum. The tines may all extend at the same angle or at different angles within the preferred range.

Advantageously, the ring member is mounted in a support sleeve slidably mounted in the entry portion of the bore. This arrangement facilitates assembly and, where the cable has a protective metal sheath, ensures the earth continuity between the cable and gland body is maintained if the gland is subsequently dis-assembled for any reason, for example maintenance.

Conveniently, the support sleeve and body have cooperating formations to locate the sleeve within the body. The co-operating formations preferably comprise an external flange at one end of the support sleeve engageable with the body at said one end.

Conveniently, the confronting surfaces of the flange and body are tapered.

Advantageously, the end cap threadably engages the body at said one end and the sealing ring is mounted in an internal groove within the end cap such that the seal member is compressed onto the cable sheath on tightening the end cap.

For certain applications, for example where the gland is installed in a hazardous environment, the gland is assembled with the optional liner within the bore and filler compound used to encapsulate the unsheathed conductors within the liner.

Conveniently, the liner is a sliding fit in the bore and defines with the entry portion of the bore an annular recess at one end of the body in which the support sleeve and ring member are received.

Preferably, the liner comprises a hollow ferrule having opposed end portions complementary to the entry and exit portions of the bore and a radial web extending between the end portions which seats against an internal abutment shoulder extending between the entry and exit portions of the bore.

Other features and advantages of the invented cable gland will be apparent from the following description of exemplary embodiments with reference to the accompanying drawings wherein: FIGURE 1 is a longitudinal section of a first embodiment of a cable gland according to the present invention; FIGURE 2 is an end view of the cable gland shown in Figure 1; with the end cap removed; FIGUPE 3 is an exploded isometric view of the component parts of the cable gland shown in Figures 1 and 2; FIGURE 4 is a longitudinal section of a cable termination incorporating the cable gland shown in Figures 1 to 3; FIGURE 5 is a longitudinal section similar to Figure 4 showing the earth continuity ring member in the upper half and the support sleeve in the lower half; FIGURE 6 is a section on the line 6-6 of Figure 5; FIGURE 7 is a longitudinal section of a second embodiment of a cable gland according to the present invention; FIGURE 8 is an end view of the cable gland shown in Figure 7; with the end cap removed; FIGURE 9 is an exploded isometric view of the component parts of the cable gland shown in Figures 7 and 8; FIGURE 1Q is a longitudinal section of a cable termination incorporating the cable gland shown in Figures 7 to 9; FIGURE 11 is a longitudinal section similar to Figure 10 showing the earth continuity ring member and filler compound in the upper half and the support sleeve and liner in the lower half; FIGURE 12 is a section on the line 11-11 of Figure 11; FIGURE 13 are sectional views of alternative profiles for the sealing ring member; and FIGURE 14 are plan views of alternative profiles for the tines of the earth continuity ring member.

Referring first to Figures 1 to 3 of the accompanying drawings, a cable gland 1 is shown comprising a hollow body 2 having a through bore 3 defining a cable passageway. The bore 3 has an entry portion 3a at one end and an exit portion 3b at the other end of reduced cross-section separated from the entry portion 3a by an internal abutment shoulder 3c.

One end of the body 2 is externally screw threaded at 2a for connection, for example to a housing (not shown) of electrical apparatus or equipment, and the other end is externally threaded at 2b for engagement by an end cap 4.

Intermediate the external screw threads 2a,2b the body 2 has an external collar 2c of hexagonal shape for engagement by a suitable tool (not shown) to facilitate mounting of the body 2 and tightening of the end cap 4 on the body 2 during assembly and installation of the gland 1.

Slidably received in the entry portion 3a of the bore 3 is a support sleeve 5 having respective internal flanges 5a,5b at each end between which an earth continuity ring member 6 is located and retained.

The support sleeve 5 further has an external flange 5c at one end having a tapered surface 5d which seats against a complementary tapered surface 2d at the end of the body 2 to limit sliding movement of the sleeve 5 into the entry portion 3a of the bore 3.

The earth continuity ring member 6 comprises a cylindrical element 6a having a plurality of radially inwardly directed flexible tines 6b. Each tine 6b has a root portion 6b' integral with one end of the element 6a and extends towards the other end of the 0 element 6a at an angle of approximately 45 to the longitudinal axis of the element 6a terminating in a tip portion 6b" lying in a common plane normal to the longitudinal axis at or adjacent to the other end of the body 6a. The sleeve 5 with the earth continuity ring member 6 mounted therein is inserted into the entry portion 3a of the bore 3 with the tines 6b extending towards the exit portion 3b of the bore 3 to assist insertion of the end of a cable as described later herein.

The end cap 4 has an internal groove 4a in which a sealing ring 7 of a resilient elastomeric material such as neoprene is retained.

The sealing ring 7 has a central aperture 7a aligned with the internal flange 5b of the sleeve 5 and a through hole 4b in a retaining flange 4c of the end cap 4.

In the assembled condition of the gland 1 shown in Figure 1, the sealing ring 7 is axially located between the end of the body 2 and the retaining flange 4c of the end cap 4 and is compressed therebetween on tightening the end cap 4 onto the body 2.

With reference now to Figures 4 to 6, there is shown application of the cable gland 1 as above-described in a termination 10 for an armoured cable 11.

The cable 11 comprises a plurality of conductors 11a enclosed within a protective outer flexible wire sheath 11b which is cut-back at the end of the cable 11 to expose the conductors lla to be connected to the apparatus or equipment as desired.

For assembly of the termination, the end cap 4 with the internal sealing ring 7 is located on the end of the cable 11. The cable 11 is then inserted into the entry portion 3a of the bore 3 until the sheath 11b seats against the abutment shoulder 3c within the bore 3. The exposed conductors lia extend with radial clearance through the exit portion 3b of the bore 3 and project therefrom as shown for connection as required.

The tines 6b of the earth continuity ring member 6 deflect outwards on insertion of the cable 11 and, due to the inherent resilience thereof, the tines 6b are urged against the sheath 11b both to provide an earth continuity connection between the cable sheath 11b and the gland body 2 and to resist withdrawal of the cable 11 from the gland 1.

Finally, the end cap 4 is tightened onto the body 2 to compress the seal member 7 which resiliently conforms to the outer profile of the sheath 11b to provide a weathertight seal at the entry end of the gland 1 and to assist further in holding the cable 11 in position.

If the end cap 4 is subsequently released, for example for inspection of the cable 11 for routine maintenance or repair, the slidable mounting of the support sleeve 5 mounting the earth continuity ring member 6 in the entry portion connection 3a of the bore 3 ensures that the earth continuity connection is maintained at all times.

Referring now to Figures 7 to 9 of the accompanying drawings, a second embodiment of the invented cable gland for use in a hazardous environment is shown, like reference numerals in the series 100 being used for parts corresponding to the first embodiment above-described.

In this second embodiment, the cable gland 101 comprises the same components as the gland 1 of the first embodiment with the addition of an optional liner comprising a hollow ferrule 112 slidably received in the bore 103.

The ferrule 112 has opposed end portions 112a and 112b connected by a radial web 112c defining an internal abutment shoulder 112d and an annular skirt 112e at one end of the same internal diameter but of reduced external diameter relative to the adjacent end portion 112a.

In the assembled gland 101, the web 112d of the ferrule 112 seats against the internal abutment shoulder 103c of the bore 103 and the skirt 112e of the ferrule 112 defines, with the entry portion 103a of the bore 103, an annular recess 113.

The support sleeve 105 and the cylindrical element 106a of the earth continuity ring member 106 are received in the recess 113 with the skirt 112e extending adjacent to the root portion 106b of the tines 106.

In other respects the construction and assembly of the gland 101 is similar to the first embodiment and will be understood by those skilled in the art from the description already given of the first embodiment.

Referring now to Figures 10 to 12, a cable termination 110 incorporating the gland 101 abovedescribed is shown, like reference numerals in the series 100 being used for parts corresponding to the termination 10 above-described.

Assembly of the termination 110 is similar to that of the termination 10 above-described except that the outer sheath 111b of the armoured cable 111 seats against the internal abutment shoulder 112d of the liner 112 and a filler compound 114, such as an epoxy putty or like insulating compound, is forced into the end portion 112b of the liner to encapsulate totally the unsheathed conductors 111a extending therethrough within the exit portion 103b of the bore 103. As best shown in Figure 11, the filler compound 114 completely fills the void space within the end portion 112b and is prevented from spreading into the opposed end portion 112a by engagement of the cable sheath 111b with the abutment shoulder 112c of the liner 112.

As will be understood, this arrangement confines the filler compound 114 within the end portion 112b of the liner 112 and prevents the filler compound contacting the body 102 and other components of the gland 101 thereby facilitating opening of the gland 101 for inspection and routine maintenance. In addition, the gland 101 may be taken apart and the main parts recovered for re-use of the gland 101 with a replacement liner 112 or without the liner as described for the first embodiment.

It will be appreciated from the foregoing description of two exemplary embodiments that the present invention provides a cable gland for terminating cable which is of simple construction and which can be readily adapted for use with a filler compound by the simple addition of the optional liner ferrule. In this way the gland may be supplied as a kit of parts for assembly by the user on site with or without the optional liner as required. As a result, the gland can be assembled for both non-hazardous and hazardous environments as designed using the same basic components and the user has to select and fit the optional liner so desired. This has considerable benefits for the manufacture and retailer as well as the user.

It will also be understood that the present invention is not limited to the exemplary embodiments above-described. For example, the flexible tines which are of rectangular shape in the exemplary embodiments may be of any suitable shape and a range of alternative shapes of tines are shown in Figure 14. Also, whilst the number of tines in the exemplary embodiments is eight, the number of tines may be selected as desired, for example ten or twelve tines may be provided. In addition, the tines may be uniformly spaced as described or non-uniformly. Furthermore, the inclination of the tines to the longitudinal axis of the gland may be selected in the range 150 to 750 and more preferably in the range 300 to 600 with the tines extending at the same or different inclinations as required.

In another modification, the seal member mounted in the end cap may have any desired external profile and a range of suitable profiles for the seal member is shown in Figure 13.

The filler compound for application of the gland to hazardous environments may be of any type known to those skilled in the art to prevent ingress of fluid and/or to provide improved fire or heat resistance.

The preferred materials for the gland body, end cap, liner ferrule, support sleeve and ring member are metals or alloys such as brass, aluminium, steel, stainless steel, gun metal or combinations thereof.

The same material may be used for all these components or different materials may be used for one or more components as desired.

Finally, it will be understood that the cable gland of the present invention is not limited to the termination of wire armoured cable but has application to cables having any type of protective metal sheath as well as to cables having an insulating outer sheath that is pierced by the tines both to retain the cable with the gland body and, where provided, to engage a metal reinforcement or the like to provide the earth continuity connection.

Claims

Claims:

1. A cable gland for the termination of a cable having a plurality of conductors within a protective outer sheath, the gland comprising a hollow body having a through bore defining a passageway for the cable, the bore having at one end an entry portion for the sheathed cable and at the other end an exit portion through which the unsheathed conductors extend with the bore being adapted to receive an optional liner for encapsulation of the unsheathed conductors by a filler compound, a ring member mounted in the entry portion for engagement with the cable sheath, an end cap engageable with the body, and a seal member arranged within the end cap for engagement with the cable sheath.

2. A cable gland according to Claim 1 wherein the ring member has a plurality of radially inwardly directed flexible tines for resilient engagement with the cable sheath.

3. A cable gland according to Claim 2 wherein the ring member is adapted to provide earth continuity between the gland body and the cable.

4. A cable gland according to Claim 2 or Claim 3 wherein the tines extend towards the exit portion of the bore.

5. A cable gland according to any one of Claims 2 to 4 wherein the tines are uniformly spaced apart in the circumferential direction.

6. A cable gland according to any one of Claims 2 to 5 wherein the ring member has an even number of tines.

7. A cable gland according to any one of Claims 2 to 6 wherein the tines extend at an angle to the central longitudinal axis of the ring member.

8. A cable gland according to Claim 7 wherein the tines extend at an angle in the range 150 to 750

9. A cable gland according to Claim 8 wherein the tines extend at an angle in the range 300 to 600.

10. A cable gland according to Claim 9 wherein the tines extend at an angle of "O

11. A cable gland according to any one of Claims 7 to 10 wherein the tines extend at the same angle.

12. A cable gland according to any one of Claims 7 to 9 wherein the tines extend at different angles.

13. A cable gland according to any one of Claims 2 to 12 wherein the tip portions of the tines terminate in a common plane transverse to the central longitudinal axis of the ring member.

14. A cable gland according to any one of the preceding Claims wherein the ring member is received in a support sleeve mounted in the entry portion of the bore.

15. A cable gland according to Claim 14 wherein the ring member comprises a cylindrical element provided with the tines that is located and retained between axially spaced internal flanges of the sleeve member.

16. A cable gland according to Claim 14 or Claim 15 wherein the support sleeve is slidably mounted in the entry portion and the support sleeve and body have cooperating formations to locate the sleeve within the entry portion.

17. A cable gland according to Claim 16 wherein the co-operating formations comprise an external flange at one end of the support sleeve engageable with the body at said one end.

18. A cable gland according to Claim 17 wherein the confronting surfaces of the flange and body are tapered.

19. A cable gland according to any one of the preceding Claims wherein the end cap threadably engages the body at said one end and the sealing ring is mounted in an internal groove within the end cap such that the seal member is compressed onto the cable sheath on tightening the end cap.

20. A cable gland according to any one of the preceding Claims wherein the exit portion is of reduced cross-section relative to the entry portion with an internal abutment shoulder connecting the entry and exit portions for engagement by the sheathed cable for locating the cable in the bore.

21. A cable gland according to any one of the preceding Claims including the liner and a filler compound for encapsulating the unsheathed conductors within the liner.

22. A cable gland according to Claim 21 wherein the liner defines with the entry portion of the bore an annular recess at one end of the liner in which the ring member is received.

23. A cable gland according to Claim 21 or Claim 22 as dependent on Claim 20 wherein the liner is slidably received in the bore and comprises a hollow ferrule having opposed end portions complementary to the entry and exit portions with a radial web extending between the end portions of the ferrule for seating against the abutment shoulder and providing an abutment face for engagement by the cable sheath.

24. A cable gland substantially as hereinbefore described with reference to Figures 1 to 6 of the accompanying drawings.

25. A cable gland substantially as hereinbefore described with reference to Figures 7 to 12 of the accompanying drawings.

26. A cable gland substantially as hereinbefore described with reference to Figures 1 to 6 of the accompanying drawings as modified by any one of the alternatives shown in Figure 13 and/or by any one of the alternatives shown in Figure 14 of the accompanying drawings.

27. A cable gland substantially as hereinbefore described with reference to Figures 7 to 12 of the accompanying drawings as modified by any one of the alternatives shown in Figure 13 and/or by any one of the alternatives shown in Figure 14 of the accompanying drawings.

28. A kit of parts for use in assembling a cable gland according to any one of the preceding Claims.