Clamping members and clamping devices

A clamping arrangement which includes an elongate member having a plurality of strands wound around one another in a plurality of turns of each strand. The clamping arrangement further includes a clamping device which includes a clamping member for clamping the elongate member. The clamping member has an engaging means for engaging the elongate member. The engaging means is configured to engage half or more of the total number of strands forming the elongate member. The clamping device further includes a fixed reaction member, and urging means to urge the clamping member towards the reaction member. When the elongate member is received between the clamping member and the reaction member, the reaction member provides a reaction against the elongate member to clamp the elongate member in the clamping device.

This invention relates to clamping members for use in clamping devices. This invention also relates to clamping devices.

The use of clamping members in clamping devices is known. An example of such a clamping device is disclosed in GB patent specification No. 2240581.

According to one aspect of this invention, there is provided a clamping member for clamping an elongate member to a clamping device, the elongate member comprising a plurality of strands wound around one another in a plurality of turns of each strand, wherein each strand has substantially the same pitch as each other strand, and the clamping member has engaging means for engaging the elongate member, the engaging means being configured to engage half or more of the total number of strands forming the elongate member.

According to one aspect of this invention, there is provided a clamping arrangement comprising an elongate member having a plurality of strands wound around one another in a plurality of turns of each strand, a clamping device comprising a clamping member for clamping the elongate member, wherein the clamping member has an engaging means for engaging the elongate member, the engaging means being configured to engage half or more of the total number of strands forming the elongate member, and the clamping device further includes a reaction member, and urging means to urge the clamping member towards the reaction member, and wherein when the elongate member is received between the clamping member and the reaction member, the reaction member provides a reaction against the elongate member to clamp the elongate member in the clamping device.

In the embodiment described herein, the reaction member and the clamping member extending over half or more of the total number of strands in the elongate member provides the advantage that the elongate member is clamped tightly between the clamping member and the reaction member, and the risk of the elongate member being cut by the clamping member is minimised. The reaction member may be a fixed reaction member.

When the elongate member is clamped between the clamping member and the reaction member, each strand of the elongate member is engaged by one or both of the clamping member and the reaction member.

Each strand may be in the form of a helix. The elongate member may be a wire, cable, rope or the like.

The clamping member may have a body. The engaging means may be provided on the body.

In one embodiment, where the elongate member has six strands, the engaging means may engage three or more of the strands.

Desirably, the engaging means may be configured to engage two thirds or more of the total number of strands forming the elongate member. In one embodiment, where the elongate member has six strands, the engaging means may engage four or more of the strands.

Desirably, the engaging means may be configured to engage at least three quarters of the total number of strands forming the elongate member. In one embodiment, where the elongate member has eight strands, the engaging means may engage six or more of the strands.

More desirably, the engaging means may be configured to engage all of the strands of the elongate member. In one embodiment, where the elongate member has six strands, the engaging means may engage all six strands.

The engaging means may have a dimension which may be substantially equal to 50% or more of the pitch of the strands in the elongate member. The engaging means may be configured to engage the elongate member, such that the aforesaid dimension of the engaging means extends along the elongate member. The dimension may be the length of the engaging means.

As used herein, the word “pitch” means the length of one complete turn of a strand measured along the main longitudinal axis of the elongate member.

The aforesaid dimension of the engaging means is desirably substantially equal to 67% or more of the pitch of the strands. The aforesaid dimension of the engaging means is desirably substantially equal to 75% or more of the pitch of the strands. The aforesaid dimension of the engaging means is desirably substantially equal to 100% or more of the pitch of the strands.

The clamping member may comprise a preliminary engaging projection to initially engage the elongate member. The preliminary engaging projection may comprise a tooth on the engaging means. The clamping member may comprise a plurality of the aforesaid preliminary engaging projections, such as three preliminary engaging projections. Each preliminary engaging projection may comprise a respective tooth.

The engaging means may comprise an engaging surface, which may have with a plurality of gripping formations. The gripping formations may comprise serrations, wherein each serration extends across the engaging surface.

The clamping member may be elongate, having a length and comprising front and rear regions, the front region leading the rear region when the clamping member is urged into engagement with the elongate member, and the front region being thinner than the rear region. The clamping member may be in the form of a wedge. The engaging means may have an engaging length which is between approximately three fifths and approximately three quarters of the length of the clamping member.

The front region of the clamping member may be convexly curved to facilitate engagement of the engaging means with the elongate member. The curvature may extend from the front region to the engaging means. The curvature of the front region may extend between approximately one quarter and approximately one third of the length of the clamping member.

The clamping member may be movable between a clamping position and a release position. The engaging means may be configured to grip the elongate member when the clamping member is in the clamping position. The reaction member may be configured to allow adjustment of the position of the elongate member relative thereto when the clamping member is in the release position.

The reaction member may have a reaction surface to engage the elongate member. The reaction surface may be smoother than the engaging means of the clamping member, thereby to allow the aforesaid adjustment of the elongate member when the clamping member is in the release position.

According to another aspect of this invention, there is provided a clamping device for clamping an elongate member, the clamping device comprising a housing defining a passage to receive the elongate member, a clamping member as described above arranged in the housing to clamp the elongate member in the passage, and urging means to urge the clamping member towards the passage, wherein the clamping device includes a reaction member fixed relative to the housing to provide a reaction against the elongate member received in the passage when the clamping member is urged towards the passage to clamp the elongate member.

The passage may be defined by a reaction member and a reaction element arranged opposite one another and angled towards one another. The reaction member may comprise a wall. The reaction element may comprise a second wall.

The clamping device may define a pair of passages into each of which an elongate member can be received. The elongate members received in the respective passages may be different elongate members, or different regions of the same elongate member.

The clamping device may comprise a pair of clamping members, each of which being associated with a respective one of the passages. The clamping device may comprise a pair of urging means, each of which being arranged to urge a respective one of the clamping members towards the passage with which it is associated.

In one embodiment, the clamping device may have a single reaction member associated with each passage. The reaction member may have two surfaces, and each surface may provide a reaction against a respective elongate member in each passage.

In another embodiment, the clamping device may have two reaction members, each being associated with a respective one of the passages. Each, reaction member may comprise a respective wall. Each, reaction element may comprise a respective second wall. The, or each, wall may be part of the housing.

A clamping member10for use as part of a clamping arrangement100is shown inFIG. 1. The clamping member10comprises a body12, and engaging means on the body12, the engaging means being in the form of an engaging surface14. The clamping member10is generally in the form of an elongate wedge having a narrow front region10A, and a wide rear region10B.

FIG. 2shows the clamping arrangement100comprising the clamping member10, a clamping device18and an elongate member20in the form of a wire, cable, rope or the like. InFIG. 2, the clamping member10is shown in the clamping device18, clamping the elongate member20. Although not shown inFIG. 2, the elongate member20is formed of a plurality of strands22A,22B,22C,22D,22E and22F. The strands22A to22F are shown more clearly inFIG. 3, and discussed below.

A part of the clamping device18is shown diagrammatically inFIG. 2, and in more detail inFIG. 5. The clamping device18comprises a housing24defining a passage26for receipt of the elongate member20and the clamping member10. The passage26has an article receiving channel28through which the elongate member extends, and a space30in which the clamping member10is held.

The passage is defined between a fixed reaction member in the form of a first wall32, and a fixed reaction element in the form of a second wall34angled at an acute angle relative to the first wall32.FIG. 2shows the clamping device in use, and it can be seen that the elongate member20is received in the article receiving channel28and engages the first wall32. The clamping member10is provided in the space30between the elongate member20and the second wall34.

Urging means in the form of a compression spring36urges the clamping member10in the direction indicated by the arrow Z from a release position, in which the clamping member is disengaged from the elongate member20and a clamping position, in which the clamping member10clamps the elongate member20against the first wall32.

The angled second wall34urges the clamping member onto the elongate member20so that a clamping force is applied on the elongate member20. The engaging surface14of the clamping member10engages the elongate member20and the elongate member20is clamped between the first wall32and the clamping member10. The first wall32acts to provide a reaction force against clamping force applied by the clamping member10onto the elongate member20.

The engaging surface14has gripping formations in the form of a plurality of serrations38. The serrations38extend one after another along the length of the engaging surface14, and each serration38extends laterally across the engaging surface14. The serrations38provide enhanced grip between the clamping member10and the elongate member20compared with a smooth engaging surface14.

In addition to the serrations38, the engaging surface14also has two preliminary engaging projections40at the rear region10B of the clamping member10. The preliminary engaging projections40are provide to engage the elongate member20before the serrations38, to provide purchase onto the elongate member20to prevent it from slipping before the elongate member20is engaged by the serrations38.

It is desirable that clamping member10moves with the elongate member20during clamping of the elongate member20against the first wall32. It is also desirable that the elongate member20can move relative to the clamping device18during the clamping of the elongate member onto the first wall.

In order to ensure that the clamping member10moves with the elongate member20, the engaging surface14is provided with the aforesaid gripping formations in the form of the serrations38. In order to ensure that the elongate member20can move relative to the clamping device18, the first wall32is made to be smooth, to allow the elongate member20to slide over the first wall32until the elongate member20has been clamped thereto by the clamping member10.

The elongate member shown inFIG. 2is a simplified representation of the elongate member, which is shown more clearly inFIG. 3, and now described.

The elongate member20comprises six strands22A,22B,22C,22D,22E and22F. The strands22A to22F are helically wound around one another in a plurality of turns of each strand22A to22F. Each of the strands22A to22F has a pitch P. The elongate member20has a longitudinal main axis XX. The pitch P is the distance along the main axis XX of the elongate member20of one complete turn of one of the strands22A to22F. InFIG. 3, the pitch of the strand22A is shown, but it will be appreciated that the pitch of each other strand22B to22F is the same.

The clamping member10has a length L1extending from the front region10A to the rear region10B. The engaging surface has a length L2, which is between approximately three fifths and approximately three quarters of the length L1of the clamping member10.

The front region10A of the clamping member10has a curved leading surface10C, which curves convexly from the front end region10A to the engaging surface14. The curved leading surface10C facilitates movement of the clamping member10along the passage26in engagement with the elongate member20. The curved leading surface10C extends between approximately one quarter and approximately one third of the length L1of the clamping member10.

The length L2of the engaging surface14is also shown inFIG. 3and as can be seen, the whole length of the engaging surface14engages each of the strands22A to22F. This means that, in use, when a clamping member10having an engaging surface14of length L2is used to clamp an elongate member20formed of six strands22A to22F, each having a pitch P, each of the strands22A to22F is engaged by the clamping member10and by the first wall32.

It has been discovered that instead of engaging all six strands22A to22F, the clamping member10can engage only three of the strands, say22A to22C. With such engagement, the remaining strands22D to22F are in engagement with the first wall32at points that are directly opposite the points of engagement of the strands22A to22C with the engagement surface14.

Thus, when the engaging surface14engages the three strands22A,22B and22C, and applies a clamping force to the strands22A,22B and22C, the region of the first wall32in alignment with the clamping surface14engages the other three strands22D to22F, and the first wall32applies a reaction force to each of the strands22D,22E,22F.

The arrangement of the strands22A to22F is shown more clearly inFIG. 4, which is a diagrammatic representation of an elongate member20. Each of the strands22A to22F is shown partially spaced from the other strands so that they can be seen more clearly. Where the engaging surface14of the clamping member10extends along the three strands22A,22B and22C, the wall32engages the other three strands22D,22E and22F. The broken lines A-D, B-E, and C-F show the points on the respective strands22A and22D,22B and22E,22C and22F that are opposite each other and hence engaged by either the clamping member10or the region of the first wall32aligned with the engaging surface14.

Thus, with the use of a clamping member10with an engaging surface14that extends across three of the strands22A to22F, all of the strands are clamped by the clamping member10against the first wall32.

FIG. 5shows an example of a clamping arrangement100comprising the features of the clamping arrangement100described above. The features shown inFIG. 5have the same reference numerals as the corresponding features shown inFIGS. 1 to 4. The clamping device18shown inFIG. 5also includes a release member for releasing the clamping member10from the elongate member20.

In the embodiment shown inFIG. 5, the release member comprises a screw50threadably secured to the rear region10B of the clamping member10. The clamping member10can be moved to its release position by pulling the screw50in the direction indicated by the arrow Y.

The embodiment of the clamping device18shown inFIG. 5has securing formations52to secure the clamping device18to a further article (not shown). Each securing formation52comprises a wing member54defining an aperture56. Each wing member54extends outwardly form the housing24on opposite sides thereof. A fastening member such as a bolt can be received through each aperture56to secure the clamping device18to the article.

There is thus described a clamping member10that has an engaging surface14that is of such a length that all of the strands of a multi-strand elongate member20can be clamped by a clamping device. There is also described a clamping arrangement and a clamping device18that enables an elongate member to be clamped more firmly than prior art clamping devices, and reduces the risk of such clamping cutting through the elongate member20.

Various modifications can be made without departing from the scope of the invention.