GB2111324A

GB2111324A - Cable stripping

Info

Publication number: GB2111324A
Application number: GB08234923A
Authority: GB
Inventors: Neville James Ditchfield
Original assignee: BICC PLC
Current assignee: Balfour Beatty PLC
Priority date: 1981-12-09
Filing date: 1982-12-08
Publication date: 1983-06-29
Also published as: GB2111324B

Abstract

A device (1) for removing the metal armouring or sheathing (8) from an electric cable (3) for reclamation purposes, in which the device comprises a cutter (2) which rotates about an axis transverse to, and passing through, the longitudinal axis of the cable to cut a longitudinally extending slot (10) in the metal covering and to draw the cable through the device; and means for opening out the slotted metal covering to allow separation of the conductor or conductors from the metal covering. <IMAGE>

Description

SPECIFICATION Cable stripping This invention relates to a device for, and a method of, separating the metal or metal alloy sheathing or armouring (hereinafter for convenience referred to as metal covering) from around the conductor or conductors of an electric cable, to allow for reclamation of the materials of the cable.

In a known device two spaced toothed rollers grip opposite sides of a cable, and on rotation force the cable onto a fixed blade which splits the metal covering to form a longitudinal opening therein. Further rotation of the rollers forces the opening onto a fixed wedge-shaped member which opens out the metal covering to allow easy separation of the conductor or conductors of the cable from the metal covering. This device has the disadvantage that it works solely by force, and in use the fixed blade becomes blocked by the materials of the cable, preventing further use. As a result only short lengths of cable can be fed through the device, to allow the blade to be cleared between each feed. Obviously this results in a slow throughput. Further, this device can only be used on cables down to 2.5 cm in diameter.

Cables having a smaller diameter tend to be too flexible to be forced onto the fixed blade. Also this device is arranged such that the toothed rollers grip the cable at a position offset from the longitudinal axis of the cable and the fixed blade is positioned adjacent a face of one of the rollers, again making the device unsuitable for cables under 2.5 cm diameter as smaller cables cannot be gripped and split with this arrangement.

According to the present invention a device for separating the metal covering (as hereinbefore defined) from around the conductor or conductors of an electric cable comprises a cutter which rotates about an axis transverse to, and passing through, the longitudinal axis of the cable to cut a longitudinally extending slot in the metal covering and to draw the cable through the device; and means for opening out the slotted metal covering to allow separation of the conductor or conductors from the metal covering.

This device has the advantage that the slot in the metal covering is cut rather than split, and therefore requires no gripping and forcing arrangements. Further this device can be used on any size of metal covered cable. Further still, as the metalcovering is cut rather than split, the cutter does not tend to become blocked, which aliows a continuous feed of cable through the device, resulting in a much faster throughput.

Preferably. the device further comprises straightening rollers positioned upstream of the cutter to straighten the cable before it is drawn through the cutter. The rollers are preferably driven to assist in drawing the cable through the device, and are preferably adjustable to allow for cables of sizes differing from one another.

The cutter preferably cuts the metal covering of the cable in a guide block, the cutter passing through an aperture in the guide block substantially perpendicular to, and opening into, a second aperture through the guide block, through which the cable passes. The second aperture is preferably so shaped as to prevent substantial sideways movement of the cable in the guide block, and is preferably adjustable in size to allow for cables of sizes differing from one another.

The device may also include flattening rollers positioned upstream of the cutter, which can flatten the cable, if required, before it is fed to the cutter. By flattening the cable, its rigidity can be increased.

Preferably the cutter has a variable speed control, such that its speed can be varied to allow for changes in cable materials and/or rate of drawing of cable.

Where a cable has a covering of plastics material (e.g. PVC) over the metal covering, the device may also include a slitting knife positioned upstream of the cutter for removing the plastics covering. Similarly, where a cable has a layer of plastics material under the metal covering, a slitting knife may be positioned downstream of the cutter for removing this plastics layer.

Where a cable has more than one metal covering, the device preferably comprises two or more cutters at spaced positions along the route of a cable, each cutter cutting a slot in one or more of the metal coverings.

The cutter is preferably a milling cutter comprising an elongate member of substantially cylindrical shape, which member is rotatably driven about its longitudinal axis, and has in its circumferential surface cutting edges on helical flutes in the surface.

The means for opening out the metal covering preferably comprises a fixed wedge-shaped member, although any other suitable means may be used. The separated conductor or conductors can be fed onto a take-up drum which is preferably driven to assist in drawing the cable through the device.

The device preferably has cooling means for dissipating heat generated by the cutter.

This invention also includes a method of separating the metal covering from around the conductor or conductors of an electric cable using the device hereinbefore described.

The invention is further illustrated by a description, by way of example, of the preferred device in accordance with the invention with reference to the accompanying drawings, jn which Figure 1 is a side view of the device; and Figure 2 is a cross-sectional view on the line Il-Il in Figure 1.

The device 1 shown in the drawings comprises a variable speed milling cutter 2 which rotates about an axis transverse to, and passing through, the longitudinal axis of a cable 3, a fixed wedged shaped member (not shown) downstream of the cutter, a guide block 4 and driven rollers 5 upstream of the cutter. The guide block 4 has a through aperture 6 for the cable 3, and an aperture 7, which opens into the through aperture, for the cutter 2.

The cable 3, which has a metal sheath and an insulated conductor 9, passes through the rollers 5 which straighten the cable and assist in drawing the cable through the device 1, and into the through aperture 6 of the guide block 4. The cutter 2, which has been set to cut a predetermined depth into the cable 3 to form a longitudinally extending slot 10 in the metal sheath 8, extends through the aperture 7 in the guide block 4 to protrude into the through aperture 6. As the cable 3 passes through the through aperture 6 the cutter 2 torms the slot 1 ü and drives the cable through the device 1. The cut cable 3 then passes to the fixed wedge shaped member which opens out the slot 10 and allows separation of the metal sheath 8 and conductor 9.

Claims

1. A device for separating the metal covering (as hereinbefore defined) from around the conductor or conductors of an electric cable comprising a cutter which rotates about an axis transverse to, and passing through, the longitudinal axis of the cable to cut a longitudinally extending slot in the metal covering and to draw the cable through the device; and means for opening out the slotted metal covering to allow separation of the conductor or conductors from the metal covering.

2. A device as claimed in Claim 1 , wherein said device also comprises straightening rollers positioned upstream of the cutter to straighten the cable before it is drawn through the cutter.

3. A device as claimed in Claim 2, wherein the rollers are driven to assist in drawing the cable through the device, and are adjustable to allow for cables of sizes differing from one another.

4. A device as claimed in any one of the preceding Claims, wherein the cutter passes through an aperture in a guide block, which aperture is substantially perpendicular to, and opens into, a second aperture through the guide block, through which the cable can be passed.

5. A device as claimed in Claim 4, wherein the second aperture is so shaped as to prevent substantial sideways movement of the cable in the guide block, and is adjustable in size to allow for cables of sizes differing from one another.

6. A device as claimed in any one of the preceding Claims, wherein the cutter has a variable speed control, such that its speed can be varied to allow for changes in cable materials and/or rate of drawing of cable.

7. A device as claimed in any one of the preceding Claims, wherein the cutter is a milling cutter comprising an elongate member of substantially cylindrical shape, which member is rotetably driven about its !ongitudinal axis, and has in its circumferential surface cutting edges on helical flutes in the surface.

8. A device as claimed in any one of the preceding Claims, wherein the means for opening out the metal covering comprises a fixed wedge shaped member.

9. A device as claimed in any one of the preceding Claims, wherein the device also includes cooling means for dissipating heat generated by the cutter.

10. A device for separating the metal covering (as hereinbefore defined) from around the conductor or conductors of an electric cable substantially as hereinbefore defined with reference to, and as shown in, the accompanying drawings.

11. A method of separating the metal covering from around the conductor or conductors of an electric cable using a device as claimed in any one of the preceding Claims.