GB2106336A

GB2106336A - Electric cable glands

Info

Publication number: GB2106336A
Application number: GB08225160A
Authority: GB
Inventors: John Blundell Hutchison
Original assignee: BICC PLC
Current assignee: Balfour Beatty PLC
Priority date: 1981-09-04
Filing date: 1982-09-03
Publication date: 1983-04-07
Also published as: GB2106336B

Abstract

A barrier gland for electric cables includes a body 1 which is threaded for mounting in an aperture and a compressor 2 which is so engageable with the body as to prevent free relative rotation about the axis of the gland while allowing axial sliding movement. The body and compressor are urged together by a gland nut 5, and they either form the compound chamber of the gland between them or form a recess in which a ferrule 10 is received to form the compound chamber. A counterbore 6 in the compressor member receives a contractible ring 7 compressed by a nut 9 to grip and if desired seal on to the cable. <IMAGE>

Description

SPECIFICATION Electric cable glands This invention relates to electric cable glands of the type, now known in the industry as a "barrier" gland, in which two annular members are shaped to form between them an annular chamber which when the gland is used is filled with a hardenable sealing compound in a pasty or viscous condition after which the two members are urged together to cause the sealing compound to extrude from the chamber and to penetrate into and seal interstices between and around the cores of the cable where it passes through the axial openings of the annular members.

Preferred known designs of barrier gland are described and claimed in the specifications of our British Patents Numbers 1 524683 and 1 524684.

These barrier glands have proved technically and commercially successful for armoured cables, but have not proved as convenient as might be desired for use on un-armoured cables.

In accordance with the present invention, a barrier gland comprises: a body member threaded for mounting in an aperture; a compressor member so engageable with the body member as to prevent free relative rotation about the axis of the gland while allowing axial sliding movement; means for urging the compressor member axially towards the body member; a radially contractible ring housed in a counterbore in the end of the compressor member remote from the body member; and a ring nut threadedly engaging the end of the compressor member remote from the body member to effect contraction of the ring; the body member and the compressor being shaped to form between them an annular recess.

This recess may itself be the compound chamber of the gland; or it may receive one or more than one other annular member to form the compound chamber either between two such other annular members or between one such annular member and either the body member or the compressor. Preferably the compound chamber is so formed between the compressor member and one such other annular member (a ferrule) as to prevent the sealing compound from adhering to the body member so that the cable, compressor and resin seal can be withdrawn as a unit from the finished termination.

Preferably the engagement between the body member and the compressor member is such that any substantial relative rotation is prevented, but this is not essential and a free movement of a substantial proportion of a revolution, or even more, might be permitted provided that there is some limit to ensure that the compressor is held by the body member to allow the nut to be screwed up and unscrewed without the need to use a second spanner to hold the compressor member. Any suitable interlocking formation can be used to achieve this result; a preferred arrangement when the compressor member is machined from hexagonal stock is to leave a hexagon flange at some point along the length of the compressor member and form in the interior of the body member grooves to receive the vertices of the flange, say by broaching.

The preferred means for urging the compressor member axiallv towards the body member is a gland nut threaded on the body member and bearing on a suitable shoulder on the compressor member (such as the appropriate side of the flange just referred to) but other conventional means could be used.

Preferably the contractible ring is of an inert resilient material, e.g. polychloroprene or any other suitable rubber, in which case a skid washer is preferably used; but if a seal is not required a split collet could be used (the counterbore and/or the nut being appropriately shaped).

The invention will be further described. by way of example, with reference to the accompanying drawings in which Figure 1 is a longitudinal section through one form of gland in accordance with the invention and Figure 2 is an exploded view showing only two members of the gland.

In the drawings, 1 is the body of the gland, and receives the compressor 2 slideably but nonrotatably through the engagement of the flange corners 3 on the compressor with grooves 4 in the body, as best seen in Figure 2. These members are urged together by a gland nut 5, and the compressor member has a counterbore 6 in which is received a polychloroprene grooved washer 7 of conventional design, together with a skid washer 8. The counterbore is threaded and receives a nut 9, which has a mating male thread, and which is formed at its outer end with a hexagon or any other suitable gripping formation. The compound chamber of the gland is formed between the compressor 2 and a ferrule 10, which forms a complete lining for the body member 1 and projects so as to be visible in the finished joint, as in conventional barrier glands.

In use, the gland is first loosely assembled on the cable-end without inserting any sealing compound. The body member 1 is screwed into its mounting aperture, and the cable is firmly gripped by sliding the compressor member 2 into the body member 1 to hold it against rotation and then tightening the nut 9 to the ring 7. This defines the position of these members on the cable.

Compressor member 2 is then withdrawn with the cable gripped in it, and the cable-end prepared, after which the appropriate amount of sealing compound is mixed and introduced into the compound chamber as seen at 11. On reassembly, the sealing compound is compressed between the compressor member 2 and the ferrule 10 by tightening the gland nut 5 and extrudes through the open end of the ferrule, so that the sealing compound as well as the ferrule is visible for inspection in the finished termination.

Whilst the ring nut 9 is shown threadedly engaged in the open end of the counterbore of the compressor member, the invention is not so restricted as the ring nut may be so shaped as to threadedly engage the outer surface of the compressor member.

Claims

1. A barrier gland comprising: a body member threaded for mounting in an aperture; a compressor member so engageable with the body member as to prevent free relative rotation about the axis of the gland while allowing actual sliding movement; means for urging the compressor member axially towards the body member; a radially contractible ring housed in the counterbore in the end of the compressor member remote from the body member; and a ring nut threadedly engaging the end of the compressor member remote from the body member to effect contraction of the ring; the body member and the compressor being shaped to form between them an annular recess.

2. A barrier gland comprising: a body member threaded for mounting in an aperture; a compressor member so engageable with the body member as to prevent free relative rotation about the axis of the gland while allowing sliding movement; means for urging the compressor member axially towards the body member; a radially contractible ring housed in a counterbore in the end of the compressor member remote from the body member; a ring nut threadedly engaging the end of the compressor member remote from the body member to effect contraction of the ring; and a ferrule in the said recess shaped to form between itself and the compressor member a chamber for the reception of sealing compound.

3. A barrier gland as claimed in Claim 1 or Claim 2 in which the compressor member and the body member are so engaged as to prevent any substantial relative rotation between them.

4. A barrier gland as claimed in Claim 3, wherein the compressor member has a hexagonal flange vertices of which engages longitudinal grooves in the interior of the body member for the purpose specified.

5. A barrier gland as claimed in any one of the preceding Claims, wherein the contractible ring is of an insert resilient material.

6. A barrier gland as claimed in any one of Claims 1 to 4, wherein the contractible ring is a split collet.

7. A barrier gland substantially as described with reference to and as shown in the drawings.