GB2503035A

GB2503035A - Bus-bar clamp

Info

Publication number: GB2503035A
Application number: GB201210693A
Authority: GB
Inventors: James Devereux; Clive Spence
Original assignee: SILVERTRONIC Ltd
Current assignee: SILVERTRONIC Ltd
Priority date: 2012-06-15
Filing date: 2012-06-15
Publication date: 2013-12-18
Also published as: WO2013186571A1; GB201210693D0

Abstract

A bus-bar clamp for making an electrical connection with a bus-bar comprises: a non-conductive first clamp member 100 having a first clamp surface 140; a non-conductive second clamp member 200 having a conductive second clamp surface 240 formed thereon; and an electrical connector 400 mounted on the second clamp member 200 and electrically connected to the conductive clamp surface 240. The first clamp surface 140 may be formed of an elastically compressible member (e.g. a polymer, rubber or nylon pad). The clamp may include a nut 300 and a threaded member 110 to apply a clamping force to the first and second clamp surfaces 140, 240 to hold a bus-bar between them. The threaded member 110 may be integrally formed with the first clamp member 100 and the second member 200 may have an opening for receiving the threaded member 110. Also disclosed is a method of manufacturing a clamp that comprises the steps of: moulding first and second non-conductive clamp members 100, 200; providing a conductive surface on the second clamp member 200; mounting an electrical connector 400 on the second clamp member 200; and electrically connecting the conductive surface to the electrical connector 400.

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 cf 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 siidably 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 elcngated 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 cf 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 siidable 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 foroe to urge the second clamp surfaoe 240 towards the first olamp 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 seoond olamp 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 350mm2 to 550mm2 Preferably, the area is about 0mm2.

The height of the pad when formed as a solid pieoe 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 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 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.