GB2299462A - Cord grip - Google Patents

Abstract

A cord grip for an electrical accessory in which a first member (2) having a first cable gripping surface is biased towards a second member (8) having a second gripping surface so that the cable to be gripped (20) lies between the gripping surfaces. In order to prevent the gripping surfaces drifting relative to each other in a plane roughly parallel to the gripping planes so that the cable "walks" out of the grip, a protrusion (12, 13) is provided at one end of the or each gripping surface which extends towards the opposition gripping surface.

Description

CORD GRIP The present invention relates to a cord grip.

Cord grips of various designs for locking an electrical cable into an electrical accessory such as a plug where the cable needs to be safely secured to the accessory are well known. Commonly, they comprise a strap screwed over a recess into which the cable is fitted. In order to avoid the necessity of using a screw driver and the possibility of loosing screws, we have designed a vane type cord grip for a plug in which a pair of angled vanes acting as gripping arms either side of a recess, grip the cable with their inner surfaces.

This arrangement works well where the recess is enclosed by the plug cover since the cable is securely trapped between the vanes on each side, and by the top and bottom of the recess defined by the cover and base of the plug.

In a situation where a cord grip is provided in an accessory where the recess is only partially defined such that the cable is not fully trapped within the recess, the cable as it moves under use in relation to the accessory tends to work out of the opposed gripping surfaces of the gripping arms. This is caused by the gripping surfaces shifting relative each other substantially in a plane parallel to the gripping planes.

A cord grip according to a first aspect of the invention comprises a first member at one end of which is a first cable gripping surface biased toward a second opposed cable gripping surface to grip a cable between the surfaces, the first surface having at one end a protrusion extending therefrom in a direction toward one end of the second surface.

The protrusion acts so as to prevent a cable gripped between the surfaces from riding along the first surface and working out of engagement between the surfaces. this is particularly important for smaller sizes of cable where there would otherwise be a risk that the cable would roll out of engagement between the surfaces and would roll under a side perpendicular to the first surface.

Preferably each surface has such a protrusion and there are two such members, that it the first and a second member, each formed of resilient material to provide the necessary bias.

Each member may be joined together so as to provide a single unit that has means to securely engage the grip in an accessory. Each surface at the other end to the end having the protrusion may be sloped with first slopes away from each other to provide a substantially "V" shaped notch to assist the entrance of a cable between the surfaces and these surfaces may be further sloped outwardly with second slopes at right angles to the first slopes. The surfaces are preferably toothed to provide a better grip and the teeth may extend so that their tips extend to an arc which ensures that whatever the size of cable gripped between opposed teeth, the teeth can act towards each other in substantially the same plane ensuring a good grip.

Preferably at least one of the teeth is truncated with respect to at least one other of said teeth so as to provide an end surface opposing the protrusion of the same cable gripping surface. The truncated tooth or teeth prevents the rotation of a cable inserted between the gripping surfaces. This is particularly advantageous when a small cable is to be gripped since whilst the protrusion or protrusions prevent the cable rolling downwards over the gripping surfaces the truncated tooth or teeth prevent the cable from rolling upwards in a direction along the length of the tooth or teeth.

In a further aspect of the invention there is provided an electrical accessory having a cord grip according to the first aspect of the invention. The cord grip may be formed as wholly or a part of the accessory or may be separately fixed into the accessory. Thus said first member may be a part of or separate from the accessory with the second surface on or separate from accessory or both the first member and second surface can be separate from the accessory but fixed thereto.

In a further aspect the accessory can have a hole or recess adjacent a location for the cord grip through which the cable can be inserted into the grip. The hole or recess can be provided with a stop retainable in the hole or recess by means of the grip.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a rear plan view of an accessory fitted with a cord grip according to the invention, Figure 2A is a plan view of a cable entry blanking plug for insertion into the accessory of Fig. 1, Figure 2B is a front elevation of the blanking plug of Fig. 2A, Figure 2C is a side elevation of the blanking plug of Fig. 2A, Figure 3 is a perspective view of the cord grip seen from below, that is from the side where it fits against the front plate of the accessory of Fig. 1, Figure 4 is a front elevation of the cord grip of Fig.

3, Figure 5 is a cross sectional view of the cord grip of Fig. 3 taken from V-V of Fig. 4, Figure 6 is a perspective view of one arm of the cord grip of Fig. 3 taken from VI of Fig. 5, Figure 7 is a perspective view of the cord grip of Fig. 3 with a cable inserted as seen from below, Figure 8 is a part cross section side view of the grip of Fig. 3 showing insertion of a cable, Figure 9 is a similar cross section to Fig. 8 with a cable inserted.

The cord grip shown in the drawings has a first member 2 at one end of which is a first cable gripping surface 4 biased toward a second opposed cable gripping surface 6 on a second member 8 by means of resilience of the members which are joined by a base portion 10. The surfaces 4 and 6 each have respectively protrusions 12, 13 extending in a direction toward the inner ends of opposite surface, each protrusion seats on its bottom surface 15 against a recess 14 in the front plate 16 of the accessory 18 of Fig. 1 which is diagrammatically a switch. The function of the protrusions 12, 13 is to prevent a cable 20 from riding along the first surface and working out of engagement between the surfaces as will be described below with the aid of Figures 7 to 9.

The surfaces are each arcuately shaped as may be seen in Fig. 1 extending from the inner protrusion end 22 to an outer end 24 which ensures that at least a pair of teeth 26 on the surfaces face directly towards each other no matter the diameter of the cable 20. Inner said teeth 26' stop short of the bottom surface 15 so that the inner teeth 26' are truncated with respect to the outer teeth 26 (see Figs.

3 and 4) so as to form a gap 17 defined in part by end surfaces 19 of teeth 26' into which gap a small cable can be trapped. This prevents such a cable from rotating.

At the outer ends 24 of the surfaces, the surfaces each have a first surface portion 28 which together provide a "V" shaped notch to assist the entrance of each cable 20 between the surfaces. Each have also a second surface portion 30 which slope outwardly toward the outer ends 24, the second surface portions being at right angles to the first surface portion.

The lower surface 32 of the members 2 and 8 are sloped upwards towards elbows 34 which enables the grip to be slid at an angle into recess 14 in the front plate 16.

The base portion 10 has a lug 36 and ribs 38 and 40 which latter fit into grooves 42 and 44 respectively in switch casing 46. The lug 36 is trapped in a groove 48 in the under side of casing 46 so that the grip is securely fixed into the casing and between the casing and front plate.

The recess 14 may be enlarged to broken lines 49 so that the members 2 and 8 can open out further than shown in Fig.

1 to allow a greater gap between the gripping surfaces 4 and 6 and hence enable a larger diameter cable 20 to be gripped.

Shown in Fig. 1 is a U shaped cable recess 50 in front plate 16 adjacent cord grip recess 14 for receiving and locating cable 20. Into cable recess 50 is slid a stop or blanking plug 52 shown in detail in Fig.s 2A-2C. The plug 52 has a shallow V shaped inner surface 54 which is engaged when fitted into recess 50 by the outer ends 24 of the cord grip surfaces 4 and 6 to retain the plug into the recess 50. Projections 56 from the plug prevent the plug from being forced out of recess 50 by engaging on the inner surfaces 58 of rim 60 of the front plate.

Figures 8 and 9 show the insertion of cable 20 in direction A into gripping location between the members 2 and 8 (member 2 being hidden from view by member 8).

Figure 7 shows the function of projection 12 and 13 particularly when there is a distortion of member 8 which without projection 13 engaging on the under side 62 of cable 20 would result in cable 20 "walking" out of engagement with teeth 26.

Whilst two gripping members 2 and 8 are provided for the cable grip, it is possible to have a single member with one gripping surface.

Whilst the opposed gripping surface is provided on the front plate on one side of recess 14. However, this arrangement does not provide for such a range of cable sizes.

Claims (14)

CLAINS

1. A cord grip comprising a first member at one end of which is a first cable gripping surface biased toward a second opposed cable gripping surface to grip a cable between the surfaces, the first surface having at one end a protrusion extending therefrom in a direction toward one end of the second surface.

2. A cord grip as claimed in claim 1 wherein the second surface is provided at one end with a second protrusion extending therefrom in a direction toward the end of the first surface.

3. A cord grip as claimed in claim 1 or 2 wherein the second opposed gripping surface is at one end of a second member and is biased towards the first gripping surface.

4. A cord grip as claimed in claim 3 wherein the first and second members are each formed of resilient material to provide the said bias.

5. A cord grip as claimed in claim 4 wherein the first and second members are joined together so as to provide a single unit.

6. A cord grip as claimed in any one of the preceding claims wherein the gripping surfaces are provided with teeth.

7. A cord grip as claimed in claim 6 wherein at least one of the said teeth is truncated with respect to at least one other of said teeth so as to provide an end surface opposing the protrusion of the same cable gripping surface.

8. A cord grip as claimed in claim 5 wherein the lower surfaces of the members are sloped upwards to enable the grip to be slid at an angle into a grip receiving recess of an electrical accessory.

9. A cord grip substantially as described with reference to Figures 1 and 3 to 7 of the accompanying drawings.

10. An electrical accessory having a cord grip as claimed in any one of the preceding claims.

11. An electrical accessory as claimed in claim 6 wherein a cable recess is provided through which a cable may be passed to enable it to be inserted into the cord grip.

12. An electrical accessory as claimed in claim 11 wherein a blanking plug is provided to close the cable recess.

13. An electrical accessory as claimed in claim 12 wherein the blanking plug is arranged to be retained in the cable recess by means of the cord grip.

14. An electrical accessory substantially as described with reference to Figures 1, 2A, 2B, 2C, 8 and 9 of the accompanying drawings.

14. An electrical accessory substantially as described with reference to Figures 1, 2A, 2B, 2C, 8 and 9 of the accompanying drawings.

Amendments to the claims have been filed as follows

1. A cord grip comprising a first member at one end of which is a first cable gripping surface biased toward a second opposed cable gripping surface to grip a cable between the surfaces, the first surface having at one end a protrusion arranged for abutment with the cable extending therefrom in a direction toward one end of the second surface, said protrusion being displaced from the or any gripping surface.

2. A cord grip as claimed in claim 1 wherein the second surface is provided at one end with a second protrusion extending therefrom in a direction toward the end of the first surface.

3. A cord grip as claimed in claim 1 or 2 wherein the second opposed gripping surface is at one end of a second member and is biased towards the first gripping surface.

4. A cord grip as claimed in claim 3 wherein the first and second members are each formed of resilient material to provide the said bias.

5. A cord grip as claimed in claim 4 wherein the first and second members are joined together so as to provide a single unit.

6. A cord grip as claimed in any one of the preceding claims wherein the gripping surfaces are provided with teeth.

7. A cord grip as claimed in claim 6 wherein at least one of the said teeth is truncated with respect to at least one other of said teeth so as to provide an end surface opposing the protrusion of the same cable gripping surface.

8. A cord grip as claimed in claim 5 wherein the lower surfaces of the members are sloped upwards to enable the grip to be slid at an angle into a grip receiving recess of an electrical accessory.

9. A cord grip substantially as described with reference to Figures i and 3 to 7 of the accompanying drawings.

10. An electrical accessory having a cord grip as claimed in any one of the preceding claims.

11. An electrical accessory as claimed in claim 6 wherein a cable recess is provided through which a cable may be passed to enable it to be inserted into the cord grip.

12. An electrical accessory as claimed in claim 11 wherein a blanking plug is provided to close the cable recess.

13. An electrical accessory as claimed in claim 12 wherein the blanking plug is arranged to be retained in the cable recess by means of the cord grip.