GB2089586A

GB2089586A - Improvements in and relating to cable securing devices

Info

Publication number: GB2089586A
Application number: GB8037809A
Authority: GB
Original assignee: LEWDEN METAL PRODUCTS Ltd
Current assignee: LEWDEN METAL PRODUCTS Ltd
Priority date: 1980-11-25
Filing date: 1980-11-25
Publication date: 1982-06-23
Also published as: GB2089586B

Abstract

A cable securing device comprises a first member (1) to which a cable (5) is to be secured, said member having an opening including a tapped portion (2) and a tapered seating (3). An annular collar (4), which is formed of resilient material and is clamped within the seating (3) by means of a screw-threaded bush member (7), has a frustoconically tapered outer surface (7B) having a taper angle which is smaller than that of the seating (3) in order to promote effective compression of the collar (4) to clamp the cable (5) within its central bore (4A). The collar (4) may have a series of radial slots (6) to facilitate compression thereof. <IMAGE>

Description

SPECIFICATION Improvements in and relating to cable securing devices This invention concerns improvements in and relating to cable securing devices, and more especially to devices for securing flexible electrical cable in the neck of a connecting plur or similar device, in order to anchor the cable against inadvertent withdrawai.

It is an object of the present invention to provide such a device which will secure the cable in a fluid-tight manner, and which can accommodate a range of cable diameters.

The invention accordingly provides a cable securing device comprising a first member with respect to which the cable is to be secured, said member having an annular opening or recess for receiving the cable, said opening or recess including a tapped portion and, inwardly of said tapped portion, a tapered seating; an annular collar member of resilient material having a central bore for receiving the cable to be clamped and a tapered external surface for engagement with said tapered seating of said first member; and a second member in the form of a screw-threaded bush arranged to admit the cable through a central bore thereof, and to be screw-threaded into engagement with the tapped portion of said first member in order to clamp said resiliently deformable collar member into engagement with the said tapered seating, whereby said collar member is compressed around the circumference of the cable in order to clamp the cable in a substantially fluid-tight manner.

In order to enable the said collar member to accommodate a wider range of cable sizes the central bore of the collar member may be tapered in the same direction as its external surface. Thus, when the collar is threaded onto a cable of larger diameter than the narrower end of the bore, the smaller end of the collar will stretch to accommodate the cable.

Preferably, the said tapered seating, the tapered external surface and internal bore of the said collar member, and the forward end of the said second member all comprise tapered frustoconical surfaces, the angles of taper being different from one another in order so as to compress said collar member further to promote fluid-tight sealing. For example, the said tapered seating may comprise an angle of 220, the external surface of said collar member a taper angle of 150, and the forward surface of the threaded bush member a taper angle of 180.

Advantageously, the external surface of the said collar member is radially slotted, the radial slots terminating short of the central bore of the collar member and of the outer end of the collar member; the flexibility of this slotted construction allows the collar member to accommodate a wider range of cable diameters, while the continuous annular core forms the desired fluidtight seal between the cable and the seating of said first member.

The invention is illustrated by way of example in the accompanying drawings, the single figure of which is an exploded perspective view of a cable securing device in accordance with the invention.

Referring to the drawing, the cable clamping device comprises a first member 1, which may, for example, comprise the body of an electrical plug or socket, said member 1 having a female tapped portion 2, at the inner end of which is provided a tapered frustoconical seating 3. The seating 3 has a taper angle of, for example, 220. A collar member 4 which is formed of resiliently deformable material such as rubber, comprises a tapered central bore 4A arranged to receive an electrical cable 5, and a tapered frustoconical outer surface 4B, which has, for example, a taper angle of 15 . This outer surface of the collar member is provided with a series of radially extending slots 6 which terminate short of the internal bore 4A, ieaving a continuous annular core 4C, and also terminate short of the outer peripheral edge 4D of the collar member.

A threaded bush member 7 comprises a male screw-threaded portion 7A, a frustoconically tapered forward end 7B and a central bore 7C. The angle of taper of the forward end 7B has, for example, an angle of taper of 18 .

A flat steel washer 8 is arranged between the bush member 7 and the collar member 4 to reduce friction upon the back face of the collar member 4.

In use, the electrical cable 5 is threaded through the central bore 7C of the bush member 7, through the central bore 4A of the collar member 4, and is then inserted into the member 1, where the bared ends of the electrical leads are secured to appropriate electrical terminals.

The cable 5 may be of any desired diameter within the range capable of being accommodated by the collar member 4. That is to say that the cable diameter is preferably within the range of diameters between those of the smaller and larger ends of the central bore 4A. When the collar member is threaded over a cable of greater than the minimum diameter, therefore, the smaller end of the collar member 4 expands to accommodate the cable. This expansion is facilitated by the presence of the longitudinal slots 6 which enable the bore 4A to stretch to the extent that its two ends are of the same diameter, when the largest cable is accommodated therein.

The collar member 4 is then pushed into the member 1 until it engages the tapered seating 3, and the bush member 7 is screwed into the tapped portion 2 in order to compress the collar member 4 and clamp the cable 5 in the bore 4A.

Owing to the differing tapering angles of the seating 3 and the collar member 4, and, to a lesser extent, the tapered forward end of the bush member 7, the collar member 4 is thereby effectively compressed into engagement with the outer circumference of the cable 5, so that the latter is secured against inadvertent displacement from the member 1. It is a particular advantage of the illustrated arrangement that the collar member 4 also provides an effective seal against entry of water or other moisture between the cable 5 and the member 1. Moreover, a range of diameters of cable can be accommodated within the bore of the flexible collar member 4, so that a limited number of units can cover a large number of cable diameters.

The natural tendency for rubber to return to its original position when under compression pushes the collar member 4 upwards thus causing friction and locking between the flank angles of the male thread on the bush 7 and the female thread 2 in the neck of the plug. This obviates tendencies to loosen, such as during vibration, but does not lock to an extent that cannot easily be overcome by use of a spanner.

Claims

1. A cable securing device comprising a first 'member with respect to which the cable is to be secured, said member having an annular opening or recess for receiving the cable, said opening or recess inciuding a tapped portion and, inwardly of said tapped portion, a tapered seating; an annular collar member of resilient material having a central bore for receiving the cable to be clamped and a tapered external surface for engagement with said tapered seating of said first member; and a second member in the form of an annular bush arranged to admit the cable through a central bore thereof, and to be screw-threaded into engagement with the tapped portion of said first member in order to clamp said resiliently deformable collar member into engagement with the said tapered seating, whereby said collar member is compressed around the circumference of the cable in order to clamp the cable in a substantially fluid-tight manner.

2. A device as claimed in Claim 1, in which the central bore of the collar member is tapered in the same direction as its external surface.

3. A device as claimed in Claim 1 or 2, in which the said tapered seating of said first member and the said tapered external surface of said collar both comprise frustoconical surfaces, the angle of taper of said seating being greater than the angle of taper of the external surface of said collar so as to compress said collar member further to promote fluid-tight sealing.

4. A device as claimed in Claim 3, in which the forward end of said second member also comprises a tapered frustoconical surface, the angle of taper of which is greater than that of the external surface of said collar.

5. A device as claimed in any of Claims 1 to 3, in which the external surface of the said collar member is radially slotted to facilitate compression or expansion thereof, the radial slots terminating short of the bore of the collar and of the outer peripherai edge of the collar, so that when the collar is compressed, the collar core forms the fluid-tight seal between the cable at the seating of said first member.

6. A cable securing device substantially as described herein with reference to the accompanying drawing.