Technical Field

The present invention relates to a winch, and particularly relates to a spindle for a winch used to restrain loads carried on a truck or the like.

Background to the Invention

Drivers of trucks and the like are typically required by law to ensure that loads they carry are properly restrained. Proper restraint of loads is required to ensure the safety of other road users.

One technique used for restraining a palletted load on the bed of a truck is to utilise a length of webbing and a winch. One end of a length of chain or webbing is secured at one edge of the truck bed, is passed over the palletted load, and the free end is wound onto the winch. The winch includes a spindle which is driven by inserting one end of a bar into an aperture through the spindle and rotating the bar. A pawl on the winch cooperates with a series of teeth on the spindle to keep the winch in a tightened state.

The truck body obstructs rotation of the bar, thus the winch is tightened in a series of part rotations. The bar is rotated through a partial turn, is removed, and re- inserted into the spindle in its initial rotational position so that it can be turned again. The spindle continues to be turned a little at a time until the desired tension in the webbing is achieved.

The continual removal and re-insertion of the bar into the spindle is time consuming, particularly in the case of soft, compressible loads. Thus, it has been tried to provide a ratchet mechanism in the spindle. The bar is rotated to tighten the winch, and when its limit of rotation is reached it can be rotated back to its starting position without removing it from the aperture. The winch is kept tight by the existing pawl mechanism, and the ratchet mechanism allows the bar to rotate back to its starting position. However, to date these ratchet type mechanisms have been found to be very vulnerable to failure.

Summary of the Invention

In a first aspect the present invention provides a spindle for a winch including: a first member for winding a length of a restraint; a second member for rotationally driving the first member; the second member engages with the first member by way of an arrangement which permits relative rotational movement between the first and second members in one direction only; and a portion of the second member is received into a bore in the first member to support the second member with respect to the first member.

The portion of the second member may be a sliding fit in the bore of the first member. The second member may enagge with the first member by way of a ratchet arrangement which may include at least one cam and a plurality of followers.

The followers may be oriented to move radially with respect to the axis of rotation of the spindle.

The followers may be mounted on leaf springs. The followers may engage the cam in a compressive mode.

Brief Description of the Drawings

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a winch including a first embodiment of a spindle according to the invention;

Figure 2 is an exploded view of the winch of figure 1; Figure 3 is a cross sectional view of the spindle of the winch of figure 1; Figure 4 is a cross sectional view of the ratchet mechanism of the winch of figure 1;

Figure 5 is an end view of the capstan of the winch of figure 1; Figure 6 is a cross sectional view of the capstan of figure 1 ; Figure 7 is a cross sectional view of a second embodiment of a spindle according to the invention; and Figure 8 is a cross sectional view of the ratchet mechanism of the spindle of figure 7.

Detailed Description of the Preferred Embodiment

Referring to figure 1, a winch 10 is shown which includes a frame 12 which carries a spindle 20. The winch 10 is for use on a truck and in use is mounted at the underside of the bed of a truck by way of carriage 12. The spindle includes a first member in the form of spool 22 which is designed to wind a flexible restraint member such as a length of webbing or a chain. The spindle 22 includes an aperture 28 which receives the free end of the restraint to commence winding. A pawl 16 is provided which engages with teeth 14 to keep the winch in a tightened state. To release the restraint, the pawl 16 is released from teeth 14 in a known manner.

Spindle 20 further includes a second member in the form of capstan 24. Capstan 24 is mounted to spool 22 by way of a ratchet mechanism 26 which allows relative rotational movement between the capstan and the spool in one direction only as will now be described.

Referring to figure 2, the ratchet mechanism is shown in exploded view and includes a cam formed from two teethed rings 30 and a plurality of followers 32 which are mounted on leaf springs 34 which are formed from bent strips of metal to bias them to move radially outwardly to engage with the teeth on rings 30. A cap plate 28 secures the ratchet mechanism together. Two rubber O rings 35 are mounted in grooves in capstan 30 to prevent dirt or moisture from entering the ratchet mechanism. In some embodiments, one toothed ring is used instead of two.

Referring to figure 3, in the region indicated by arrow A it can be seen that a portion of the capstan 24 extends into, and is a sliding fit inside, a bore provided in the centre of spool 22. This arrangement serves to support the capstan with respect to the spool and resists the large forces that can be experienced when the bar is inserted through apertures 25 in capstan and is used to tighten the winch.

Referring to figure 4, the operation of the cam and followers is evident. The followers 32 are biased to move radially outwardly to engage with teeth 36 provided about the inside of ring 30. As seen in figure 4, if the capstan 24 is turned in an anticlockwise direction, then the followers bear against teeth 36 to drive the spool in an anti-clockwise direction. However, if the capstan is rotated in a clockwise direction, then the followers may slip past the teeth by compression of the leaf springs 34. During this movement the spool is restrained from moving in a clockwise direction by the pawl 16 and teeth 14 arrangement (see figures 1 & 2). Thus, a bar inserted in apertures 25 may be rotated back and forth in a series of clockwise and anti-clockwise part turns without removing the bar from the capstan and the restraint will become progressively tightened.

Referring to figures 7 and 8, an alternative embodiment of the invention is shown where like reference numerals in the series 100-199 are used to indicate components corresponding to the first embodiment. In this embodiment, the followers 132 are mounted on coil springs 134 seated in apertures in capstan 124. The followers in this embodiment operate in a shear mode, rather than a compressive mode.

It can be seen that embodiments of the invention have at least the following advantages: • Rapid tightening of restraint saves time

• Capstan is supported by the spool to lend strength to the winch to extend service life. Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.

Finally, it is to be appreciated that various alterations or additions may be made to the parts previously described without departing from the spirit or ambit of the present invention.