GB2432624A

GB2432624A - Gripping device for an elongate element

Info

Publication number: GB2432624A
Application number: GB0522816A
Authority: GB
Inventors: Terence Raymond Dingley; Steven Ferry
Original assignee: Doby Cleats Ltd
Current assignee: Doby Cleats Ltd
Priority date: 2005-11-09
Filing date: 2005-11-09
Publication date: 2007-05-30
Also published as: GB0522816D0

Abstract

A gripping device comprises a housing with aligned apertures 6, 6' for receiving an elongate element such as a wire and a pair of grip elements 2 pivoted therein to provide facing toothed surfaces. The grip elements 2 can pivot between an open condition allowing the passage of the elongate element and a gripping condition engaging the elongate element against movement. The elements 2 allow movement of the elongate element in an insertion direction (from aperture 6 to aperture 6') and grip by cam action to prevent movement in the opposite direction. A element such as a spring 5 biases the elements 2 to the gripping condition and a sliding button can engage both elements to move them to the open condition against the bias. Two set of apertures and gripping elements can be provided in the housing (as shown).

Description

Gripping Device

Field of the Invention

This invention relates to a gripping device, and in particular to a device for gripping an elongate strand of material such as wire.

Background of the Invention

Gripping devices are used in many applications. For example, joining together wire strands in fencing applications, to suspend an object from a wire, to suspend sports equipment, or to suspend objects from structural elements of a building.

Gripping devices are known from the patent documents referred to below: GB 2210517, WO 95/30844 and WO 97/36123 for examples of wire gripping devices in which toothed wedges grip the wire.

GB 2240581 describes a gripping device of the type described in the above-mentioned patents where the toothed wedges are replaced by ribbed rollers.

GB 2,322,435, GB 2378979 and GB 2378980 illustrate how a gripping device oi the type described in the above-mentioned patents may be deployed.

WO 92/12766 describes a gripping device for gripping a cord which supports a ball.

One problem associated with the known gripping devices is that when placed under excess load, or if the gripping device is defective, the gripped elongate element can pull through the gripping device. Obviously, this is undesirable and could have disastrous consequences.

Another problem associated with the known gripping devices is that they are difficult to adjust.

The afore-mentioned problems are not solved by the inventions proposed in the above-mentioned patent applications.

It would therefore be desirable to provide an improved gripping device.

Summary of the Invention

According to one aspect of the invention, there is provided a gripping device as specified in Claim 1.

According to another aspect of the invention, there is provided a method of gripping an elongate element as specified in Claim 13.

Other preferred features of the invention are set out in the appended claims.

The gripping device of the invention provides a number of advantages over the prior art.

First, the elongate element is engaged from either side rather than one side only. Second, the grip clement is rotatably rather than sildably mounted so that as more force is exerted on an elongate member, the closer together the grip elements come. Third, the device can be used with a wider range of cross-sections of elongate element. Fourth, the device of the invention is much simpler to adjust than the known gripping devices, which require the use of alien keys to first slacken off the gripping element so that the gripped element can be moved. The device of the invention provides for simple adjustment of the gripped clement by moving the adjustment buttons in the direction against the force of the tension spring.

Brief Description of the Drawings

In the drawings, which illustrate a preferred embochment of the invention, and are by way of

example:

Figure 1 is an exploded view of a grippmg device according to the invention; Figure 2a is an end view of a the gripping device illustrated In Figure 1 when assembled; Figure 2b is a plan view of the gripping device illustrated in Figure 2a; Figure 3a is schematic representation of a base plate of the gripping device illustrated in Figure 1; and Figure 3b is a front view of the base plate illustrated in Figure 3a.

Detailed Description of the Preferred Embodiments

Referring now to Figures 1 and 2, the gripping device comprises a base plate I which mounts two pairs of grip elements 2, and for each pair of grip elements 2 a button 3 and a spring 5.

Each grip clement 2 is a cam and has a toothed surface 2a, the toothed surfaces 2a of a pair of gripping elements facing each other. The base plate I includes openings 6, 6' through which an elongate element such as a wire may be passed. In use, such a wire is presented upto the opening 6 and pushed towards the opening 6', between which is located a pair grip elements 2. Inserting a wire causes the grip elements 2 to be pushed apart against the force generated by the spnng 5. The wire is pushed through the opening 6' until it protrudes out of the said opening. The sprmg 5 pushes together the respective grip elements 2 of a pair and causes the teeth to of the grip elements 2 to bite into the surface of a wire located between the two said grip elements. When a force is exerted on the wire along the axis of said wire in a direcuon from the opening 6' towards the opening 6, the teeth of the grip element 2 are caused to bite Into the wire further.

The base plate I will now be described in greater detail with reference to Figures 3a and 3b.

The base plate I is formed from a block of suitable material, such as metal or plastics, and the openings 6, 6' arc formed therein as bores. The base plate 1 includes two housings 7, each housing including a pair of slots 7a, a pair of sockets 7b, and a spring housings 7c. The sockets 7b are cylindrical and have an opening 7d along one side.

Figure 1 best illustrates how the grip elements 2 are mounted in the base plate 1. Each end of the grip element 2 comprises a substantially cylindrical clement which fits into a socket 7b thereby providing for the grip element 2 to rotate in the housing 7. The spring 5 is located in the spring housing 7c and acts on a pair of grip elements 2 to bias the elements together. In the example the spring is a compression coil spring.

The button 3 has a pair of spaced apart legs 3a, which locate in slots 7a. The distance between the legs 3a and slots 7a is such that each leg engages with one grip element of a pair, the purpose of the button 3 being to push the grip elements of a pair in the direction from opening 6 to opening 6', so that the position of a wire in the gripping device can be adjusted manually.

Typically, prior art gripping devices rely of a sliding cam to engage with a wire. As the cam slides into gripping engagement with the wire the wire is pressed against a flat surface. In some devices the flat surface is deformable to assist in preventing the wire from being pulled from the gripping device unintentionally.

The present invention utilises a pair of rotating cams, each having a toothed surface for engagement with a wire. The rotatable mounting of the cams in the housing ensures that the greater the load put on a wire passing through the device, the more the grip elements bite into the surface of the wire.

Claims

Claims 1. A gripping device comprising a pair of spaced apart and

aligned openings for receiving an elongate element, a pair of grip elements each provided with a toothed surface, the toothed surfaces of the grip elements facing each other, wherein each grip element is rotatable between an open condition in which an elongate element may pass between the grip elements of a pair, and a gripping condition in which the teeth of each grip element engage with the elongate element.

2. A gripping device according to Claim 1, wherein the device comprises a housing and the grip elements are rotatably mounted in the housing.

3. A gripping device according to Claim 2, wherein the housing comprises a pair of spaced apart sockets and the grip elements each include an element which engages with the socket.

4. A gripping device according to any preceding claim, further comprising biasing means arranged to bias the grip elements of a pair into the gripping condition.

5. A gripping device according to Claim 4, wherein the biasing means is a spring.

6. A gripping device according to Claim 4, wherein the biasing means is a compression spring.

7. A gripping device further comprising adjustment means, the adjustment means being arranged to change the position of the grip elements.

8. A gripping device according to Claim 7, wherein the adjustment means comprises a movable element located in the housing and arranged to engage with each grip element of a pair, and a button connected to the movable element and actuable externally of the housing.

9. Gripping apparatus comprising at least two gripping devices as claimed in any precedmg claim.

10. Gripping apparatus according to Claim 9, wherein the at least two gripping devices are mounted in a single housing.

11. Gripping apparatus according to Claim 9 or 10, wherein the at least two gripping devices are arranged such that elongate elements are inserted between the grip elements froni opposite directions.

12. A method of gripping an elongate element comprising the step of exerting a first force on the elongate element in a first direction to introduce said element into and through the aligned openings of a gripping device as claimed in any of Claims I to 9 such that the end of the elongate element inserted into the opening passes between the toothed surfaces of a pair of grip elements, and exerting a second force on the said elongate element, said second force having a component acting in a second direction substantially opposite to the said first direction.

13. A gripping device substantially as shown in, and as described with reference to, the drawings.