WO2013186571A1

WO2013186571A1 - A clamp

Info

Publication number: WO2013186571A1
Application number: PCT/GB2013/051562
Authority: WO
Inventors: James Devereux; Clive SPENCE
Original assignee: Silvertronic Limited
Priority date: 2012-06-15
Filing date: 2013-06-14
Publication date: 2013-12-19
Also published as: GB201210693D0; GB2503035A

Abstract

The present invention relates to a clamp. Particularly, but not exclusively, the invention relates to a clamp having two clamp members for clamping a bus bar in order to form a connection. A bus bar clamp for making an electrical connection with a bus bar, comprising a first clamp member (100) having a non-conductive body with a first clamp surface; a second clamp member (200) having a non-conductive body with a conductive second clamp surface formed thereon; and an electrical connector (240) mounted on the second clamp member and electrically connected to the conductive clamp surface.

Description

A CLAMP

The present invention relates to a clamp. Particularly, but not exclusively, the invention relates to a clamp having two clamp members for clamping a bus bar in order to form a connection .

Bus bar clamps are known in the art. However, these are slow to attach to, or remove from, a bus bar.

There is therefore a need for a bus bar clamp that enables connection with a bus bar to be quickly achieved.

According to a first aspect of the invention there is provided a clamp.

According to a second aspect of the invention there is provided a method of forming an electrical connection with a bus bar.

According to a third aspect of the invention there is provided a method of manufacturing a clamp.

For a better understanding of the invention, and to show how the same may be put into effect, the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a first view of a clamp forming a first embodiment of the invention;

Figure 2 shows a second view of the clamp of Figure 1; Figure 3 shows an exploded view of the clamp of Figure 1 ; and

Figure 4 shows a view of the abutting surfaces of a second clamp member and a nut forming part of the embodiment of Figure 1.

As can be seen in Figure 1, a first embodiment of a clamp, comprises a first clamp member 100 having a first clamp surface 140. The first clamp member 100 includes a base 105 and threaded member 110 extending from one end of the base 105. Preferably, the threaded member 110 extends

perpendicularly to the base 105. Preferably, the threaded member 110 is integrally formed with the base 105. The threaded member 110 includes a male thread 112 that extends from the end distal the base 105 towards the base.

Preferably, the length of the threaded member 110 is in the range 20mm to 100mm. More preferably, the length of the threaded member 110 is around 50mm.

Preferably, the diameter of the threaded member 110 is in the range 5mm to 15mm. More preferably, the diameter of the threaded member 110 is around 10mm.

The clamp also comprises a second clamp member 200 having a second clamp surface 240. The second clamp member 200 has an opening 210, into which the threaded member 110 may be inserted. The second clamp member 200 can therefore be slidably mounted on the threaded member 110. Thus, the second clamp member 200 can translate along the longitudinal axis of the threaded member 110 to move the second clamp surface 240 towards or away from the first clamp surface 140.

Preferably, the first clamp member and the second clamp member comprise a non-conductive body.

Preferably, at least one of the first clamp member and the second claim member comprises one or more polymers, such as a polyamide.

More preferably, at least one of the first clamp member and the second clamp member comprises nylon.

In preferred embodiments, the second clamp member comprises an elongated tubular section 205. In such embodiments, the opening 210 forms the bore of the tubular section 205.

Advantageously, such a tubular section 205 prevents slight rotation of the second clamp member 200 relative to the first clamp member 100, by ensuring that the longitudinal axes of the bore and the threaded member 110 are closely aligned, and thereby allows the second clamp surface 240 to maintain an accurate position with respect to the first clamp surface 140. Preferably, the length of the tubular section 205 is in the range 20mm to 50mm. Most preferably, the length of the tubular section 205 is about 30mm.

In preferred embodiments, the threaded member 110 has one or more longitudinally extending groove (s) 114 for slidable engagement with one or more protrusion ( s ) 214 on the

internal surface of the opening 210. In embodiments having an elongated tubular section 205, the protrusions may be ribs 214 extending in parallel with the longitudinal axis of the bore of the tubular section 205. The interlocking groove (s) and protrusion ( s ) thereby provide means for prevent relative rotation between the first clamp member 100 and the second clamp member 200.

The clamp also comprises a nut 300. The nut 300 has a bore in which is formed a female thread 312. The female thread 312 is arranged to engage the threaded member 110. Thus, rotation of the nut 300 causes the nut 300 to move along the threaded member 110 towards or away from the base 105. The nut 300 can therefore provide a clamping force to urge the second clamp surface 240 towards the first clamp surface 140. When a bus bar is positioned between the first and second clamp surfaces 140, 240, the nut 300 can urge the two clamp surfaces 140, 240 together to clamp the bus bar.

As can be seen in Figure 4, in order to prevent slippage of the nut 300, complementary protrusions and/or depressions may be formed on the contact surfaces 280, 380 of the second clamp member 200 and the nut 300. The contact surface 280 of the second clamp member 200 surrounds the opening 210.

The complementary protrusions and/or depressions of the contact surfaces 280, 380 engage to prevent slippage of the nut 300. The materials of at least one of the second clamp member 200 and/or the nut 300 are sufficient elastic that a large force can overcome the engagement to release the nut 300. Preferably, the protrusions and/or depressions have a height in the range 0.125mm to 0.375mm.

In preferred embodiments, the nut 300 has a radially

outermost surface for gripping by a user. Preferably, at least a portion of the outermost surface is roughly

textured. For example, the nut may have a knurled outermost surface . Preferably, the nut 300 has an outer diameter in the range 10mm to 40mm. Most preferably, the outer diameter is about 25mm .

As the bus bar carries an electrical current, its inherent resistance will generate heat. This heat may cause the bus bar to expand. When the current is deactivated, the bus bar may cool and thus contract. Such expansion and contraction can cause the clamp to relax its grip on the bus bar. As can be seen from Figure 3, in preferred embodiments, the first clamp surface 140 is formed of an elastically

compressible pad. The pad 140 may be inserted within a cavity in the base 105. The pad may be glued in place. The pad may be a solid, resilient piece of material, and/or may include a spring.

The pad may comprise one or more of: a polymer; rubber; or nylon .

In preferred embodiments, the area of the pad forming the contact surface 140, when in an uncompressed state, is in the range 350mm to 550mm . Preferably, the area is about 450mm².

The height of the pad when formed as a solid piece of material maybe at least 2mm. Preferably the height of the pad is about 2mm.

The pad may have a convex abutment surface forming the first clamp surface 140. The second clamp surface 240 is conductive and is formed on the non-conductive body of the second clamp member. Thus, an electrical connection can be formed by bringing the second clamp surface 240 into contact with a bus bar. The clamp further comprises an electrical connector 400.

This is mounted on the second clamp member 200 and arranged to be in electrical communication with the second conductive clamp surface 240. The electrical connector 400 may be a plug, a socket, or a conductive lead attached to a plug or a socket.

The electrical connector 400 is preferably a socket, such as a 4mm socket. Most preferably, the electrical connector 400 is a socket integrally formed with the second clamp member 200.

The threaded member 110 has a thread 112 extending along at least a portion of its length from an end distal the base 105.

In preferred embodiments, the second clamp member 200 may comprise finger guards 230. As can be seen from Figure 2, the finger guards 230 extend outwardly from the second clamp member 200 in a direction perpendicular to the longitudinal axis of the threaded member 110. The finger guards 230 may prevent a user's fingers from inadvertently slipping from the nut 300 onto the bus bar.

The clamp described above can be used to form an electrical connection with a bus bar. A bus bars typically has a thickness in the range 2mm to 15mm .

The bus bar is positioned between the first clamp surface 140 and the second clamp surface 240.

The second clamp member 200 may be slid along the threaded member 110 towards the first clamp member 100 until the bus bar is contacted by both the first clamp surface 140 and the second clamp surface 240.

The nut 300 can be rotated about the threaded member 110 so that the contact surface 380 of the nut 300 abuts the contact surface 280 of the second clamp member 200. The nut 300 may be tightened until the bus bar is firmly held between the contact surfaces 140, 240.

The bus bar is thus clamped between the first clamp surface and the second clamp surface so that the second contact surface 240 makes an electrically conductive contact with the bus bar. Tightening of the nut 300 against the second clamp member 200 may involve partially compressing the pad.

The contact surfaces 280, 380 may engage each other to prevent inadvertent loosening of the nut 300.

A wire having an electrical connector at one end is then connected with the electrical connector 400. For example, a wire having a plug at one end may be plugged into a socket forming the electrical connector 400. The wire is thus electrically connected to the bus bar.

The first and/or second clamp member (s) 100, 200 and/or the nut 300 may be manufactured by moulding. For example, by injection moulding.

The conductive surface may be attached to the second clamp member after moulding. The electrical connector may be mounted on the second clamp member 200 after moulding.

The conductive surface is then electrically connected to the electrical connector.

Claims

CLAIMS :

1. A bus bar clamp for making an electrical connection with a bus bar, comprising:

a first clamp member having a non-conductive body with a first clamp surface;

a second clamp member having a non-conductive body with a conductive second clamp surface formed thereon; and

an electrical connector mounted on the second clamp member and electrically connected to the conductive clamp surface .

2. The clamp of claim 1, further comprising a nut and a threaded member for applying a clamping force to the first and second clamp surfaces to hold a bus bar therebetween.

3. The clamp of claim 2, wherein the threaded member and first clamp member are integrally formed.

4. The clamp of claim 2 or claim 3, wherein the second clamp member has an opening for receiving the threaded member .

5. The clamp of claim 4, wherein the second clamp member comprises a tube and the opening forms the bore of the tube.

6. The clamp of claim 5, wherein the length of the tube is in the range 20mm to 50mm.

7. The clamp of any one of claims 2 to 6, wherein the length of the threaded member is in the range 20mm to 100mm.

8. The clamp of any one of claims 2 to 7, wherein the diameter of the threaded member is in the range 5mm to 15mm.

9. The clamp of any one of claims 4 to 8, wherein second clamp member comprises protrusions and/or depressions surrounding the opening configured to engage with

complementary protrusions and/or depressions formed on the surface of the nut.

10. The clamp of claim 9, wherein the protrusions and/or depressions have a height in the range 0.125mm to 0.375mm.

11. The clamp of any one of claims 4 to 10, wherein the threaded member has one or more longitudinally extending groove (s) for slidable engagement with one or more

protrusion ( s ) on the internal surface of the opening.

12. The clamp of claim 11 as dependent upon claim 5, wherein the protrusions are ribs extending in parallel with the longitudinal axis of the tube.

13. The clamp of any preceding claim, wherein the second clamp member comprises finger guards.

14. The clamp of any preceding claim, wherein the

electrical connector is a plug.

15. The clamp of any one of claims 1 to 13, wherein the electrical connector is a socket.

16. The clamp of any preceding claim, wherein the first clamp surface is formed of an elastically compressible member .

17. The clamp of any preceding claim, wherein the first clamp surface is formed of an elastically compressible pad comprising one or more of: a polymer; rubber; or nylon.

18. The clamp of any preceding claim, wherein the first clamp surface has an area in the range 350mm 2 to 550mm2.

19. The clamp of any preceding claim, wherein the first clamp member comprises a polymer.

20. The clamp of any preceding claim, wherein the second clamp member comprises a polymer.

21. The clamp of any one of claims 2 to 20, wherein the nut has a radially outermost surface, at least of portion of which is roughly textured.

22. The clamp of any one of claims 2 to 21, wherein the nut has an outer diameter in the range 10mm to 40mm.

23. A method of forming an electrical connection with a bus bar, comprising the steps of:

clamping the bus bar with the clamp of any preceding claim; and

connecting a wire to the electrical connector.

24. A method of manufacturing a clamp comprising the steps of:

moulding a first non-conductive clamp member;

moulding a second non-conductive clamp member;

providing a conductive surface on the second clamp member ;

mounting an electrical connector on the second clamp member; and

electrically connecting the conductive surface to the electrical connector.