GB2430234A

GB2430234A - Gripping device for elongate element

Info

Publication number: GB2430234A
Application number: GB0618089A
Authority: GB
Inventors: Terence Raymond Dingley; Steven Ferry
Original assignee: Doby Cleats Ltd
Current assignee: Doby Cleats Ltd
Priority date: 2005-09-14
Filing date: 2006-09-14
Publication date: 2007-03-21
Anticipated expiration: 2026-09-14
Also published as: GB2430234B; WO2007031730A1; GB0618089D0; GB0518715D0

Abstract

A gripping device comprises at least one elongate opening 4 for receiving an elongate element, a rack 4d and pinion 5 , and means (e.g. a spring 6) for bringing the pinion 5 into engagement with an elongate element located in the said opening. The pinion 5 is mounted for translational movement in a slot 4e' having an longitudinal axis set at an acute angle to the longitudinal axis of the opening 4. A force component exerted on an elongate element located in the said opening causes the pinion to move in the slot towards the elongate element.

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 ftr examples of wire gripping devices in which toothed wedges grip the wire.

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

GB2,322,435, GB 2378979 and GB 2376980 illu'trste how a gripping device of 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.

Sununaty 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 16.

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, better engagement of the teeth of the pinion wheel is provided as a result of the pinion being rotatably mounted and engaging on one side with a rack and the other with the dongate element.

Second, the device can be used with a wider range of cross-sections of elongate element Third, 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 gnpping element so that the gripped element can be moved.

The device of the invention provides for simple adjustment of the gripped element by moving the adjustment knobs in the direction against the force of the tension spring.

Brief Description of the Drawings

in the drawings, which illustrate a preferred embodiment of the invention, 2nd are byway of

example

Figure 1 is a plan view of a gripping device according to the invention; Figure 2 is an end view of the gripping device illustrated in Figure 1; Figure 3 is a plan view of the gripping device illustrated in Figure 1 in a partially assembled forin and Figure 4 is an end view of the gripping device as illustrated in Figure 3.

Detailed Description of the Preferred Embodiments

Referring now to Figures 1 to 4, the gripping device 1 comprises a body 2 and a top plate 3.

The body 2 includes a pair of spaced apart openings 4 that extend through the body 2 from the front to the back of the device Each opening 4 has one substantially flat side 4a and an opposing side 4b induding a recess 4c. Each recess 4c indudes a toothed surface forming a rack 4d. Within the boundary of each recess 4c and located in the body 2 there is located a slot 4e which is aligned with a corresponding slot 4e' in the top plate 3. A toothed pinion wheelS is mounted on a pin 5a, which pin locates in the said slots 4e, 4e', the said slot defining a path in which the pin travels. The slots 4e, 4e' are positioned and oriented such that the teeth of the pinion wheel 5 engage with the teeth of the rack 4d, the ends of the slots 4e, 4e' defining the extreme positions of the pinion wheel. The slots 4e, 4e' are set at an angle yto the longitudinal axis of the opening 4.

The top plate 3 includes a slot 7 in which a spring 6 is located. The spring 6 is a tension spring and extends between a spring location pin 8 located in one end of the slot 7 and the pin 5a mounting the pinion wheel 5. The spring 6 biases the pinion wheel 5 to a closed position, e. the pinion wheel is biased to the position marked "x" in Figure 1. An adjustment knob 9 is mounted on the ends of each of the pins 5a to allow a user to adjust the position of the pinion wheels 5 by pulling against the tension force generated by the spring 6.

In this example, the body 2 and top cover 3 are each formed of pressed steeL The body 2 includes bores 10 which align with location pins 11 forming part of the top cover 3. The dimensions of the said bores and location pins are such that one is a press fit into the other. The device further comprises fixing screws 12 at opposite corners of the device, the fixing screws passing through corresponding through bores 13 in the top cover 3 and into threaded blind bores 14 in the body 2.

The device may be used in a number different ways. In the configuration illustrated in Figure 1, a user has, with the aid of adjustment knobs 10 moved the pinion wheels 5 towards their extreme open positions to permit an elongate element 15 such as wire to be passed through the opening 4. When the user releases the adjustment knobs the tension springs 6 pull the pinion wheel towards the position "x". The distance travelled by the pinion wheel in the slot 4e depends on the dimensions of the elongate element, the pinion wheel substantially ceasing travel when the teeth of the pinion wheel 5 engage with the surface of the elongate element. Any further travel of the pinion wheel in the slot 4e is as a result of the teeth of the pinion wheel biting into the surface of the elongate element When the device is used according to a second method, the pinion wheels are in the position "x" and are moved towards the position "y" by the insertion of an elongate element 15 into the opening in the direction "a" from the position "v". Upon insertion of the elongate element into the opening 4, the free end of the element engages with the pinion wheel 5 pushing the wheel in the direction "z", said pinion wheel moving against the force generated by the tension spring 6. When the elongate element has been pushed through the opening 4, the user ceases feeding the element in the direction "z" and the tension spring 6 pulls the pinion wheel 5 into engagement with the surface of the said element When a force is exerted on the elongate element in the direction "z" the teeth of the pinion wheel 5 are caused to bite into the said element As will be appreciated from Figure 1, when a force is exerted on an elongate element in the direction "z" a torque is applied to the pinion wheel 5 causing it to rotate about its own axis and move along the rack 4<1. The major part of the rack 4<1 is substantially straight and set at an angle to the longitudinal axis of the opening 4 so that as the pinion wheel 5 moves along the track under the influence of the said force and the force exerted by tension spring 6, the pinion wheel moves doser to the outer wall of the opening 4, thereby gripping the elongate element ever more tightly as the force in direction "zr' is increased.

The rack 4<1 also indudes a curved portion 4<11, the curve extending from one side of the opening 4 to the end of the substantially straight part of the rack 4<1. The action of the curve is to move the pinion wheelS towards the outer wall more rapidly over a unit of distance than is the case for the substantially straight part of the rack 4<1. The provision of the curved portion 4<11 allows the gripping device of the invention to be used with a wide range of cross-sections of elongate elements.

Nevertheless the dimensions of the gripping device may be optunised to match particular cross- sectional dimensions of elongate elements.

Claims

Claims 1. A gripping device comprising at least one elongate opening for

receiving an elongate eIement a rack and pinion, and means for bringing the pinion into engagement with an elongate element located in the said opening wherein the pinion is mounted for translational movement in a slot having an longitudinal axis, and the longitudinal axis of the slot is set at an acute angle to the longitudinal axis of the opening and wherein a force component exerted on an elongate deinent located in the said opening causes the pinion to move in the slot and towards the elongate element
2. A gripping device according to Claim 1, wherein the rack is formed in a recess to the elongate opening.
3. A gripping device according to Claim I or 2, further comprising biasing means arranged to bias the pinion into the path of the elongate opening.
4. A gripping device according to Claim 3, wherein the biasing means is a spnng.
5. A gripping device according to Claim 4, wherein the biasing means is a tension spring.
6. A gripping device according to any of CIaiLTLS 3 to 5, wherein the biasing means is located in a slot
7. A gripping device further comprising adjustment means, the adjustment means being arranged to change the position of the pinion.
8. A gripping device according to Claim 7, wherein the adjustment means comprises a knob mounted on one end of a shaft mounting the pinion.
9. A gripping device according to Claim 8, wherein the adjustment means comprises a knob mounted on each end of the pinion.
10. A gripping device according to any preceding claim, further comprising a housing.
11. A gripping device according to Claim 10, wherein the housing consists of two housing elements and wherein each of the elements includes a slot which slots are aligned in the assemble device, a shaft upon which the pinion wheel is mounted being located in the aligned slots.
12. A gripping device according to any preceding claim, wherein one of the housing elements indudes a channel and a recess forming part of the said elongate opening.
13. A gripping device according to Claim 10, wherein one of the housing elements indudes a slot mounting the said biasing means, said biasing means extending between a locator at one of its ends and the shaft mounting the pinion at is other end.
14. A gripping device according to any preceding claim, wherein the rack includes a substantially straight portion.
15. A gripping device according to any preceding claim, wherein the rack includes a curved portion.
16. 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 an opening ofa gripping device as claimed in any of Claims I to 15 such that the end of the elongate element inserted into the opening passes the said pinion wheel, 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.
17. A gripping device substantially as shown in, and as described with reference to, the drawings.