GB2212876A - Tensioning device - Google Patents

Abstract

A tensioning device for use in cargo handling and transportation comprises a pair of pulleys (14, 16) adapted to be connected in line with cargo retaining means. The pulleys (12, 14) are connected by a run of webbing (20). A ratchet (24) is located at one of the pulleys (12) in the webbing run. Operation of the ratchet (24) draws the webbing (20) therethrough thus drawing the pulleys (12, 14) closer together and applying a tension to the cargo retaining means. <IMAGE>

Description

TENSIONING DEVICE This invention relates to a tensioning device and in particular relates to such ansdevice for use in cargo handling and transporting systems.

In the transporation of heavy cargo, for example heavy track laying vehicles, containers, and the like on transporting vehicles, ships, and so on there is a need for the cargo to be securely held on the transporting vehicle so that it cannot move around and cause damage in transit.

With such heavy duty cargo this has normally been achieved by means of cables, chains, hawsers or webbings placed around the cargo and pulled tight by means of one or more winches. It is desirable that the cargo retainers should be subjected to a considerable tension so as to hold the cargo absolutely rigid and prevent any movement thereof.

The use of winches to achieve this is both expensive and cumbersome.

The invention seeks to provide a tensioning device improved in the above respects.

According to the present invention there is provided a tensioning device for use in cargo handling and transportation which comprises a pair of pulleys adapted to be connected in line with cargo retaining means, the pulleys being connected by a run of webbing, and characterised in that a ratchet is located at one of the pulleys in the webbing run.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevational view of a tensioning device in accordance with the invention; and Figure 2 is a top plan view corresponding to figure 1.

Referring to the drawings, it can be seen that a tensioning device generally designated 10 comprises a pair of pulley blocks 12, 14 each carrying a hook 16 or other means for attachment to cargo restraining means such as a strap, cable, chain, hawser or webbing. Each pulley block 12, 14 has two sheaves 18 round which a run of webbing 20 is passed. The webbing 20 is secured at 22 to the lower most sheave of the pulley block 14.

A ratchet 24 is attached to the pulley block 12 in effect replacing one of the sheaves 18. The run of webbing 20 is taken round the ratchet 24. The ratchet 24 includes pawls 26, 28 and a handle 30. The webbing 20 is gripped by the ratchet 24 and drawn through it in the direction of arrow A by reciprocating the handle 30 in the direction shown by arrow B. A pawl release handle (not shown in the drawings) may also be provided which withdraws the pawls from the ratchet and allows the tension to be released in the webbing 20 when it is desired to release the tension device, e.g. to release the cargo.

In operation, one of the hooks 16 will normally be attached to a fixed point on the transporting vehicle, which may be a road vehicle, train, ship or the like. The other hook 16 is then attached to the cargo restraining means which is passed over the cargo to be secured. The other end of the means may be secured to a further fixed point on the transporting vehicle. The ratchet is then operated by movement of the handle 30 drawing the two pulley blocks 12, 14 together and thus tensioning the cargo retaining means.

A typical pre-tension to be employed with a heavy duty cargo would be about 2 tonnes. Owing to the mechanical advantage of the pulley arrangement the tension on the run of webbing 20 passing through the ratchet is considerably less than the tension applied to the cargo restraining means and thus the ratchet need only be of a lighter construction than would be required were the tension to be applied directly to the cargo restraining means.

The invention therefore provides a simple, lightweight and rapidly deployable tensioning device for heavy duty cargo applications which is also economical in use.

Claims (6)

1. A tensioning device for use in cargo handling and transportation which comprises a pair of pulleys (12,14) adapted to be connected in line with cargo retaining means, the pulleys being connected by a run of webbing (20) and characterised in that a ratchet (24) is located at one of the pulleys in the webbing run whereby operation of the ratchet causes the webbing to draw the pulleys together thereby tensioning the cargo retaining means.

2. A tensioning device as claimed in claim 1 wherein each pulley (12,14) is two sheaves (18) and the webbing (20) is secured to the lowermost sheave of one of the pulleys and the ratchet (24) replaces one of the sheaves on the other pulley.

3. A tensioning device as claimed in either of claims 1 or 2 in which the ratchet includes pawls (26,28) and a handle (30) whereby reciprocation of the handle (30) draws the webbing (20) through the ratchet (24).

4. A tensioning device as claimed in any of claims 1 to 3 in which a pawl release handle is provided to withdraw pawls from the ratchet and allow tension to be released in the webbing (20) when it is desired to release the tension device.

5. A tensioning device as claimed in any of claims 1 to 4 in which hooks (16) are provided to enable the device to be connected in line with cargo retaining means.

6. A tensioning device as claimed in any of claims 1 to 5 in which the mechanical advantage of the pulley and webbing run is such that the tension applied to the webbing (20) passing through the ratchets (24) is considerably less than the tension applied to the cargo restraining means.