GB2030793A

GB2030793A - Cable terminations and means for making them

Info

Publication number: GB2030793A
Application number: GB7927235A
Authority: GB
Original assignee: BICC PLC
Current assignee: Balfour Beatty PLC
Priority date: 1977-09-27
Filing date: 1978-09-27
Publication date: 1980-04-10

Abstract

A cable gland has a spigot (2) projecting into an internal open space thereof. This receives a composite heat-shrinkable sleeve (3), which may be enclosed within the gland body. <IMAGE>

Description

SPECIFICATION Cable terminations and means for making them This invention relates to the termination of electric cables having a metallic sheathing layer (which may be an extruded or welded sheath, a tape armour layer, a screen, or wire armour) to which an electrical connection is required. More especially, though not exclusively, it is concerned with the termination of paper insulated, lead sheathed cables. Mechanical sealing glands with lead rings can be used with these cables, but especially in the case of glands with a good range-taking capacity there is a risk of over-tightening resulting in deformation of the lead sheath and consequently in damage to the underlying papers.

Our related application 38313/78 (serial No. 2005091 A) claims a method of terminating a cable having a metallic sheathing layer comprising the steps of surrounding the sheathing layer with a composite tube comprising an outer sleeve of distended elasticmemory material and an inner sleeve of metal, inserting a contact member between the composite tube and the sheathing layer and thereafter heating the composite tube to the recovery temperature of the elastic memory material, the materials and dimensions of the composite tube being such that on heating the sleeve to its recovery temperature the metallic sleeve is softened (but not melted) and the forces generated in the outer sleeve are sufficient to deform the metallic sleeve into contact with the sheathing layer and the contact member.

In accordance with the present invention, a cable terminating gland, suitable for use in the method of application 38313/78, Serial No 2005091, is distinguished by a spigot projecting into an open internal space thereof.

Usually the spigot will be on a tubular member through which the cable passes.

More especially, it is preferable for it to be on a member of a gland gripping one or more than one other layer of the cable, for example the cone of a grip for a wire-armour layer over the sheathing layer. In such cases the composite sleeve may be enclosed by the gland in the finished termination.

The spigot may have smooth or angular ribs or other gripping formations on its outer surface to increase the mechanical strength of the connection.

The accompanying drawings illustrate the use of the invention in terminating wire-armoured lead sheathed paper insulated cables.

Figures 1 and 2 are each composite sketches, the upper half of each figure showing the parts of a complete gland as supplied and the lower half the finished termination.

Figure 3 is a more detailed drawing of two components of the gland of Fig. 1 (in the assupplied condition) and Figures 4-5 show the corresponding components of a further design in the as-supplied and finished condition respectively.

As seen in Figs. 1 and 3, the armour cone 1 of an otherwise conventional gland is modified to provide a spigot 2 with annular ribs on its outer surface. Over this fits a composite tube 3 comprising an inner sleeve 4 of pure lead and an outer sleeve 5 of irradiated polyethylene that is heat-recoverable. On heating to the recovery temperature (about 1 30 C) the ends of the composite tube collapse into firm gripping, sealing and contact-making engagement with the spigot 2 and the sheath of a cable 6.

The glands of Fig. 2 and 5 are identical except that the composite tubes 3 are tapered; in Fig. 2 uniformly from end to end and in Fig. 4 over a central part joining end parts of uniform but different diameters.

CLAIMS (27 Sep 1978) 1. A cable terminating gland, distinguished by a spigot projecting into an open internal space thereof.

2. A gland as claimed in Claim 1 in which the spigot is on a member of a gland gripping at least one other layer of the cable.

3. A gland as claimed in Claim 2 in which the member is the cone of a grip for a wirearmour layer.

4. A gland as claimed in any one of the preceding claims in which the spigot has ribs or other gripping formation on its outer surface.

5. A cable termination made by means of the gland claimed in any one of the preceding

Claims.

CLAIMS (30 Nov 1979) 1. A cable terminating gland, distinguished by an annular spigot projecting from an annular end-face of one main gland member into an open internal space thereof enclosed by another main gland member.

2. A gland as claimed in Claim 1 in which the spigot is on a member of the gland gripping at least one layer of the cable.

3. A terminating gland for a wire-armoured cable having a cone grip for a wirearmour layer and distinguished by an annular spigot projecting from an annular end-face of the gripping cone into an open internal space of the gland enclosed by another main gland member.

4. A gland as claimed in any one of the preceding claims in which the spigot has ribs or other gripping formations on its outer surface.

5. A cable termination made by means of the gland claimed in any one of the preceding claims.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Cable terminations and means for making them This invention relates to the termination of electric cables having a metallic sheathing layer (which may be an extruded or welded sheath, a tape armour layer, a screen, or wire armour) to which an electrical connection is required. More especially, though not exclusively, it is concerned with the termination of paper insulated, lead sheathed cables. Mechanical sealing glands with lead rings can be used with these cables, but especially in the case of glands with a good range-taking capacity there is a risk of over-tightening resulting in deformation of the lead sheath and consequently in damage to the underlying papers. Our related application 38313/78 (serial No. 2005091 A) claims a method of terminating a cable having a metallic sheathing layer comprising the steps of surrounding the sheathing layer with a composite tube comprising an outer sleeve of distended elasticmemory material and an inner sleeve of metal, inserting a contact member between the composite tube and the sheathing layer and thereafter heating the composite tube to the recovery temperature of the elastic memory material, the materials and dimensions of the composite tube being such that on heating the sleeve to its recovery temperature the metallic sleeve is softened (but not melted) and the forces generated in the outer sleeve are sufficient to deform the metallic sleeve into contact with the sheathing layer and the contact member. In accordance with the present invention, a cable terminating gland, suitable for use in the method of application 38313/78, Serial No 2005091, is distinguished by a spigot projecting into an open internal space thereof. Usually the spigot will be on a tubular member through which the cable passes. More especially, it is preferable for it to be on a member of a gland gripping one or more than one other layer of the cable, for example the cone of a grip for a wire-armour layer over the sheathing layer. In such cases the composite sleeve may be enclosed by the gland in the finished termination. The spigot may have smooth or angular ribs or other gripping formations on its outer surface to increase the mechanical strength of the connection. The accompanying drawings illustrate the use of the invention in terminating wire-armoured lead sheathed paper insulated cables. Figures 1 and 2 are each composite sketches, the upper half of each figure showing the parts of a complete gland as supplied and the lower half the finished termination. Figure 3 is a more detailed drawing of two components of the gland of Fig. 1 (in the assupplied condition) and Figures 4-5 show the corresponding components of a further design in the as-supplied and finished condition respectively. As seen in Figs. 1 and 3, the armour cone 1 of an otherwise conventional gland is modified to provide a spigot 2 with annular ribs on its outer surface. Over this fits a composite tube 3 comprising an inner sleeve 4 of pure lead and an outer sleeve 5 of irradiated polyethylene that is heat-recoverable. On heating to the recovery temperature (about 1 30 C) the ends of the composite tube collapse into firm gripping, sealing and contact-making engagement with the spigot 2 and the sheath of a cable 6. The glands of Fig. 2 and 5 are identical except that the composite tubes 3 are tapered; in Fig. 2 uniformly from end to end and in Fig. 4 over a central part joining end parts of uniform but different diameters. CLAIMS (27 Sep 1978)

1. A cable terminating gland, distinguished by a spigot projecting into an open internal space thereof.

Claims.

CLAIMS (30 Nov 1979)

1. A cable terminating gland, distinguished by an annular spigot projecting from an annular end-face of one main gland member into an open internal space thereof enclosed by another main gland member.