GB1603523A

GB1603523A - Cable glands

Info

Publication number: GB1603523A
Application number: GB1708878A
Authority: GB
Original assignee: BRITISH ENG Ltd
Current assignee: BRITISH ENG Ltd
Priority date: 1978-04-28
Filing date: 1978-04-28
Publication date: 1981-11-25

Description

(54) IMPROVEMENTS IN OR RELATING TO CABLE GLANDS (71) We, BRITISH ENGINES LIMITED, a British Company, of Glass House Street, St.

Peter's, Newcastle Upon Tyne, NEl lBS, England, 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 a cable gland such as may be used for the entry of a cable through the wall of a housing or junction box, or other wall. The invention is particularly concerned with a cable gland for use with cables having a braided armoug or screening sheath embodied in the cable construction.

It is a requirement of such cable glands that means is provided to mechanically grip a cable passing through the gland so that the cable cannot be pulled outwards through the gland in use thus protecting the electrical connections made with the cable. Previous designs of cable gland suitable for gripping armoured and screened cables have not proved entirely satisfactory and it is an obejct of the present invention to provide a cable gland with which a braided armour or screened cable may be reliably retained in the gland.

Accordingly the present invention provides a cable gland for the entry of a cable through a wall, particularly for use with braided armour or screen cables, comprising a gland body having a shouldered screwthreaded nose portion and a mating screwthreaded locking ring or nut arranged to retain the nose portion in an aperture in the wall, the nose portion being formed with at least one transverse aperture adjacent the shoulder thereon through which an ear formed of the cable armour or screen may be passed to be gripped between the wall and the shoulder or the lock ring on tightening of the lock ring.

Preferably the nose portion is provided with at least two transverse apertures to receive respective ears formed of the cable armour or screen.

Preferably the apertures are in the form of slots which may extend from the shoulder to be open to the free end of the nose portion.

In order to promote a fuller understanding of the above and other aspects of the present invention, an embodiment will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 show in schematic cross-section a first embodiment of the invention, Figure la shows a detail of the gland body of Figure 1, Figures 2 and 2a show a schematic crosssection of a second embodiment with its associated gland body, and Figures 3 and 3a show a schematic crosssection of a third embodiment with its associated gland body.

Figure 1 of the drawings shows in schematic cross-section a gland indicated at 10 assembled in a wall 11 of a housing or junction box for the entry of a cable 12 into that housing or junction box.

The cable 12 shown is of a kind having an elastomeric outer sheath covering a braided wire armour sheath which is provided to protect the inner part and conductors of the cable.

The cable gland 10 comprises a gland body 13 which has a screw-threaded nose portion 14 arranged to pass through a suitable aperture formed in the wall 11, and to receive a screw-threaded lock ring or nut 15 to secure the gland body and thus the gland in the wall ll.

The gland body 13 is provided with an internal conical seat 16 arranged to receive an elastomeric seal ring 17. The gland body 13 has an internal screw-thread to receive a screw-threaded bush 18 provided with a hexagonal end 19 to clamp the seal 17 against the seating 16 to distort it to grip the cable 12 to form a weatherproof seal on the outer sheath of the cable 12. A synthetic plastics material slip washer 20 is interposed between the screw-threaded bush 18 and the seal 17 so that rotation of the bush 18 to screw it into the gland body does not damage the seal 17.

The external screw-thread on the nose portion 14 terminates in a shoulder 21 as best seen in Figure la. In order to mechanically grip the armour braiding of the cable 12, at least one, and preferably at least two apertures 22, are provided in the screw-threaded nose portion 14 adjacent the shoulder 21. On assembly, the armour braiding of the cable 12, is uncovered and stripped back from the cable a suitable distance and formed into ears 23 which are passed through the apertures 22 in the nose portion 14 during assembly of the cable into the gland, to be gripped between the shoulder 21 and the wall 11. on tightening of the lock ring or nut 15.

This is illustrated in Figure 1. Preferably the apertures 22 are disposed to be tangential to the surface of the shoulder 21.

Thus it can be seen that the ears 23 of the braided material are turned back to extend substantially at a right angle to the axial direction of the cable 12 and may be firmly gripped between the shoulder 21 and the wall 11. This provides the extreme mechanical resistance to the cable 12 being pulled out of the gland, the ears 23 being at the optimum angle to the axial direction of the cable for this purpose.

A washer 24 is preferably provided on assembly between the ears 23 and the wall 11 to assist in gripping the ears 23. The washer 24 may be in the form of an earth connection lug if desired.

Figures 2 and 2a show a cable gland 30 in which the apertures 22 of the previous embodiment are replaced by elongated apertures or slots 32. In order respects the embodiment is exactly similar to that shown in Figures 1 and la and the other parts are given the same reference number. It should be noted however, that the gland is shown in Figure 2 assembled in the wall 11 with the ears 23 extending on the opposite side of the wall 11 from the shoulder 21, and they are gripped between the wall 11 and the lock ring or nut 15 with the interposition of the washer 24. It will of course be appreciated that this gland can equally be assembled in the fashion of Figure 1.

Figures 3 and 3a show a cable gland 40 in which the apertures 22 of Figures 1 and la have been replaced by open slots 42 extending from adjacent the shoulder 21 to the end of the nose portion 14. In other respects this embodiment is similar to the two previous embodiments and the various parts are given the same reference numbers.

Thus it can be seen that the invention provides a cable gland which can receive and mechanically grip the braided armour or screen of a braided cable in an extremely favourable fashion to resist mechanical removal of the cable. At the same time the gland provides means for providing a weatherproof seal to the outer sheath of the cable.

It will be appreciated that the cable may be readily assembled and can provide a good electrical contact between the gland body and/or the wall 11 in which the gland is inserted, and the braided armour or screening of the cable.

WHAT WE CLAIM IS: 1. A cable gland for the entry of a cable through a wall, particularly for use with braided armour or screen cables, comprising a gland body having a shouldered screwthreaded nose portion and a mating screwthreaded locking ring or nut arranged to retain the nose portion in an aperture in the wall, the nose portion being formed with at least one transverse aperture adjacent the shoulder thereon through which an ear formed of the cable armour or screen may be passed to be gripped between the wall and the shoulder or the lock ring on tightening of the lock ring.

2. A cable gland as claimed in Claim 1 having at least two such transverse apertures equally circumferentially spaced.

3. A cable gland as claimed in Claim 1 or 2, in which the transverse apertures are circular in cross-section.

4. A cable gland as claimed in Claim 1 or 2 in which the transverse apertures are in the form of elongated holes or slots.

5. A cable gland as claimed in Claim 4, in which the slots are open to the free end of the nose portion.

6. A cable gland as claimed in any preceding claim in which the transverse apertures are tangential to the surface of the shoulder of the nose portion.

7. A cable gland as claimed in any preceding claim, including a washer on the nose portion to be interposed between the ear or ears of cable armour or screen and the shoulder or lock ring.

8. A cable gland as claimed in Claim 7, in which the washer is in the form of an earth connection lug.

9. A cable gland as claimed in any preceding claim, including means for forming a weatherproof seal with the outer sheath of a cable therein.

10. A cable gland substantially as herein described with reference to the accompanying drawings.

Il. A method of assembling the cable gland of any one of Claims 1 to 9, substantially as herein described with reference to the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. seen in Figure la. In order to mechanically grip the armour braiding of the cable 12, at least one, and preferably at least two apertures 22, are provided in the screw-threaded nose portion 14 adjacent the shoulder 21. On assembly, the armour braiding of the cable 12, is uncovered and stripped back from the cable a suitable distance and formed into ears 23 which are passed through the apertures 22 in the nose portion 14 during assembly of the cable into the gland, to be gripped between the shoulder 21 and the wall 11. on tightening of the lock ring or nut 15. This is illustrated in Figure 1. Preferably the apertures 22 are disposed to be tangential to the surface of the shoulder 21. Thus it can be seen that the ears 23 of the braided material are turned back to extend substantially at a right angle to the axial direction of the cable 12 and may be firmly gripped between the shoulder 21 and the wall 11. This provides the extreme mechanical resistance to the cable 12 being pulled out of the gland, the ears 23 being at the optimum angle to the axial direction of the cable for this purpose. A washer 24 is preferably provided on assembly between the ears 23 and the wall 11 to assist in gripping the ears 23. The washer 24 may be in the form of an earth connection lug if desired. Figures 2 and 2a show a cable gland 30 in which the apertures 22 of the previous embodiment are replaced by elongated apertures or slots 32. In order respects the embodiment is exactly similar to that shown in Figures 1 and la and the other parts are given the same reference number. It should be noted however, that the gland is shown in Figure 2 assembled in the wall 11 with the ears 23 extending on the opposite side of the wall 11 from the shoulder 21, and they are gripped between the wall 11 and the lock ring or nut 15 with the interposition of the washer 24. It will of course be appreciated that this gland can equally be assembled in the fashion of Figure 1. Figures 3 and 3a show a cable gland 40 in which the apertures 22 of Figures 1 and la have been replaced by open slots 42 extending from adjacent the shoulder 21 to the end of the nose portion 14. In other respects this embodiment is similar to the two previous embodiments and the various parts are given the same reference numbers. Thus it can be seen that the invention provides a cable gland which can receive and mechanically grip the braided armour or screen of a braided cable in an extremely favourable fashion to resist mechanical removal of the cable. At the same time the gland provides means for providing a weatherproof seal to the outer sheath of the cable. It will be appreciated that the cable may be readily assembled and can provide a good electrical contact between the gland body and/or the wall 11 in which the gland is inserted, and the braided armour or screening of the cable. WHAT WE CLAIM IS:

1. A cable gland for the entry of a cable through a wall, particularly for use with braided armour or screen cables, comprising a gland body having a shouldered screwthreaded nose portion and a mating screwthreaded locking ring or nut arranged to retain the nose portion in an aperture in the wall, the nose portion being formed with at least one transverse aperture adjacent the shoulder thereon through which an ear formed of the cable armour or screen may be passed to be gripped between the wall and the shoulder or the lock ring on tightening of the lock ring.