GB2165610A - Tensioning device - Google Patents

Abstract

A tensioning device for flexible netting or fencing comprises two elongated bars, (10, 11) pivotedly coupled together top and bottom (14, 16) and capable of being supported at one end (14, 15) to allow the clamp to be placed over the fence, arms (23, 25) for pivoting the two bars together to grip the fence and to connecting chain (24) attached to one of the arms which exerts the necessary clamping force and also tenses the fence. <IMAGE>

Description

SPECIFICATION Tensioning device This invention relates to a device for use in applying tension to an elongated member such as electrified netting as used to contain sheep or other livestock. The invention may, however, be applied more generally to the tensioning of any elongated member such as wire or cable.

To be effective the tensioning device must be able to grip the member firmly, but without causing damage, it should be adjustable to accommodate different types and dimensions, it should be capable of being positioned on the elongated member at an intermediate point in its length, and it should have ready means of attachment to a tractor, winch, or jack, for applying the tensioning force. The invention provides a very effective tensioning device which solves all the essential needs in an extremely simple and effective unit, which is economical to manufacture and extremely simple to operate.

Broadly stated the invention consists in a tensioning device comprising a clamp arranged to be opened and closed onto an elongated member to be tensioned, means to hold the clamp closed onto the member and means for applying a tensioning force to the clamp. In a preferred construction the clamp is in two parts arranged to close towards each other onto the elongate member, and including means to hold the parts inwards to the clamped position. According to a preferred feature of the invention the means for applying a tensioning force to the clamp is also arranged automatically to hold the clamp in its closed position. Conveniently the two pivoted parts of the clamp are interconnected by a chain, toggle, linkage, or tension element, which is also connected to the tensioning means.

The two parts of the clamp are preferably pivoted or otherwise arranged to be movable towards and away from each other in one direction to engage and clamp the elongated member, and can also be separated at one end to allow the clamp to be positioned on the elongated member at an intermediate position.

To obtain an effective grip without damaging the netting or other member to be tensioned the two parts preferably have co-operating matching non-planar clamping surfaces.

The invention may be performed in various ways and one specific embodiment may be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of a tensioning clamp according to the invention for use with electrified sheep netting, the clamp being shown in its open position, Figure 2 is a similar perspective view showing the clamp in the half-open position, Figure 3 is a perspective view showing the clamp closed onto a length of netting, Figure 4 is an isometric view of the lower part of the clamp, Figure 5 is a plan view of the clamp in the open position, and Figure 6 is a plan view of the clamp in its closed position.

In this example, the clamp comprises a pair of parallel upright bars 10, 11 defining an intermediate vertical slot 12 in which the netting 13 can be received. The bar 10 is of hollow square box section and the two parts are pivotally interconnected by means of a bottom peg 14 on the bar 10 which passes freely through a hole on a lug 15 secured to the lower end of the bar 11, and a further apertured lug 16 at the top end of the bar 10, which fits loosely over a metal loop 1 7 secured to a plate 18 welded to the top of the bar 11. Thus, the two bars 10, 11 can pivot about the vertical axis formed by the peg 14 and the lug 16.In the open position shown in Figs. 1 and 5, the gap or slot 12 is of considerable width and as the two parts are pivoted towards each other the width of the slot reduces until in the closed position illustrated in Figs. 3 and 6, the angle section bar 11 fits closely against two sides of the box section bar 10 and thus the two non-planar matching clamping surfaces 20, 21 effectively clamp and grip the strands of the netting fence.

The bar 10 has attached to it at mid-height a rigid handle 22 to which is attached a short length of chain 24. The bar 11 also has a rigid projecting handle 25 to which is rigidly secured a hook 26. The two handles can be used to swing the bars inwardly towards each other into the half-closed position of Fig. 2, after which the chain 24 is passed through a gap in the netting fence and engaged onto the hook 26. The winch cable, or tow cable, from a tractor is then attached to an intermediate point on the length of the chain and when tension is applied to the cable the two parts of the chain, being naturally inclined outwards from the connecting point, automatically pull the two arms 23, 25 inwards towards each other so as to increase the clamping force of the bars 10 and 11 as the tensioning force increases.After tensioning the netting it will be secured by staples, or otherwise, to fencing posts in the normal way and it is a simple matter to slacken the clamp by the reverse sequence of operations. It will be noted that the ground-engaging peg 14 can be withdrawn vertically from the lug 15 by lifting the bar 10 vertically in relation to the bar 11, this movement being permitted by the apertured lug 16 sliding on the loop 17 at the top of the bar 11. When the peg 14 is disengaged the whole bar 10 can then be pivoted upwards and outwards about the curved portion of the loop 17 so that the whole clamping device can be disengaged from and lifted off the netting. The clamp can, of course, be readily applied in this way to any intermediate point in the length of the fence.

Various modifications are possible, to suit different applications. Instead of the chain 24 the clamp may employ two or more interconnected toggle links arranged to be disconnected when needed and having a pivotal connecting point for attachment to a tensioning cable. Likewise, the bottom pivot peg 14 may be substituted by a removable peg or hinge pin, which is preferably attached permanently to one or other of the bars. In the example illustrated it will be noted that all the parts are permanently connected thus avoiding the risk of losing an essential part.

Claims (7)

1. A tensioning device comprising a clamp arranged to be opened and closed onto an elongated member to be tensioned, means to hold the clamp closed onto the member and means for applying a tensioning force to the clamp.

2. A tensioning device according to Claim 1, in which the clamp is in two parts arranged to close towards each other onto the elongated member, and including means to hold the parts inwards in the clamped position.

3. A tensioning device according to Claim 1 or Claim 2, in which the means for applying a tensioning force to the clamp is also arranged automatically to hold the clamp in its closed position.

4. A tensioning device according to Claim 3, in which the clamp is in two relatively movable pivoted parts interconnected by a chain, toggle linkage, or tension element, which is also connected to the tensioning means.

5. A tensioning device according to any of the preceding claims, in which the clamp is in two parts which are movable towards and away from each other in one direction to engage and clamp the elongated member, and can also be separated at one end to allow the clamp to be positioned on the elongated member at an intermediate position.

6. A tensioning device according to any of the preceding claims, in which the clamp includes two parts which are relatively movable towards and away from each other and have co-operating matching non-planar clamping surfaces.

7. A tensioning device for flexible fencing or netting as described with reference to the accompanying drawings.