AU717235B2 - Automatic load tensioner - Google Patents

Description

Vr -1- P/00/0011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventors: Address for service BLACKWOOD ENGINEERING PTY LTD Christopher Woodbridge Graham Gust in Australia: CARTER SMITH BEADLE 2 Railway Parade Camberwell Victoria 3124 Australia Invention Title: AUTOMATIC LOAD TENSIONER Details of Associated Provisional Application: P04018 filed 4 December 1996 The following statement is a full description of this invention, including the best method of performing it known to us -2- INTRODUCTION TO INVENTION This invention relates to load securing devices used on trucks, trailers and other vehicles.

In particular, the invention relates to a device for use with chains, straps, ropes or other such load securing means which is adapted to automatically tighten such loads after they have been initially secured to ensure that the chains, straps, ropes etc do not work loose during transit.

BACKGROUND TO INVENTION Large transport vehicles generally rely on a system of chains or straps to secure loads. Often, such chains and particularly straps are incorporated as a part of a load securing device of the vehicle or its trailer/tray in the form of winders fitted along the length of the vehicle trailer or tray.

In use, once the tray is loaded, the straps along the side of the tray would be released, unwound and drawn over the load, attached to the opposing side of the vehicle tray and wound back onto the spool of the winder until they were taunt and held in place by an integral ratchet mechanism.

'Unfortunately, such mechanisms are not self or automatically tightening and if the straps work loose in transit, the load can be placed in jeopardy.

OBJECT AND STATEMENT OF INVENTION 20 One object of this invention is to provide a load tensioner device which is •o able to automatically tighten or tension the hold on a secured load during vehicle transit.

Accordingly, in one aspect, the invention provides a load tensioning device comprising a winding means for fitting to a vehicle, said winding means having an uptake spool for holding a length of load securing means, said uptake spool capable of being limited to unidirectional or non-return rotation characterised in that said uptake spool can be automatically operated in said unidirection by co-operation with the power systems of said vehicle to periodically tighten or tension said uptake spool and securing means, whilst said vehicle is operational or in transit.

MAW:PP:#23988.CAP 2 December 1997 -3- Preferably, the uptake spool is automatically operated by connection to the pneumatic, hydraulic or electric power system of said vehicle where a power activated piston co-operates with said uptake spool to periodically operate said uptake spool in said unidirection to tighten or tension said load securing means.

The uptake spool is preferably rotated about a central axle and is mounted to a housing which is adapted for fitting to said vehicle.

The central axle may extend beyond the flanges of the uptake spool and terminate in a crank handle for manual operation at a first end and incorporate a drive pinion at a second end.

The drive pinion co-operates passively with a lock pawl to provide the unidirectional function of the winding means but also co-operates actively with a second push pawl as the means of automatically operating said uptake spool.

Preferably, the push pawl is activated by a pneumatically powered piston to periodically advance said uptake spool.

15 Preferably, the toothed drive pinion has teeth spacings which are sufficiently large to ensure a minimum quantum of tightening available from said automatic operation of said device to ensure that over tightening by incremental creep does not occur.

Preferably, the uptake spool axle is fitted to said housing by self-centering 20 bearings.

DETAILED DESCRIPTION OF THE INVENTION The invention will now be described in greater detail by reference to one -:gee: particularly preferred embodiment as shown in Figures 1 to 3.

S"Figure 1 shows a cut away plan view of the load tensioning device.

Figure 2 shows a cut away side view of the load tensioning device.

Figure 3 shows a front view of the load tensioning device.

Referring firstly to Figure 1, the load tensioning device 1 comprises a winding means 2 having an uptake spool 3 fitted thereto and mounting to the side of the vehicle chassis 16 with the assistance of a rear mount 15. The load tensioning device of the invention is adapted for fitting to the side of a vehicle, usually on the MAW:PP:#23988.CAP 2 December 1997 -4elongate trailer of an articulated vehicle for taking up and holding under tension the load securing straps or chains which are placed over a load on said trailer. The load securing straps are pulled from the uptake spool, over the load and fixed to the opposing side of the trailer and then by manually winding up the uptake spool are pulled into tension in order to secure a load on said trailer. The load tensioning device of the invention particularly incorporates a mechanism for automatically driving the uptake spool (once it has been manually drawn taunt) where the uptake spool 3 has a central axle 6 about which it is rotated and the central axle 6 is fitted to the winding means 2. The uptake spool axle is fitted to the winding means by way of self-centring roller bearings 21 to ensure minimum maintenance and smooth and reliable operation.

Referring now to Figure 2, a cut-away view from the side of the load tensioning device, particularly detailing the winding means 2, shows the mechanism of the winding means provided in a housing 5 which is fitted to the outside of the vehicle chassis 16 with the assistance of the rear mount 15. The winding means has a central axle 6 which projects through the housing 5 to directly service the uptake spool 3 (not shown). The central axle has associated therewith a drive pinion 9.

oo:. The drive pinion 9 also acts as a ratchet wheel and co-operates with a releasable lock pawl 11 which is held in engagement with the drive pinion 9 by bias rotation about 20 a shaft 17. The lock pawl ensures that the winding means and uptake spool can be limited to rotation in a one direction, that is to tighten the load securing means, by S7..i way of the passive interaction of the lock pawl with the drive pinion as it is rotated in the uptake direction and acting as a ratchet. As is common with such devices, the pawl is releasable in order to allow the uptake spool to unwind and thereby release the load securing means.

The load tensioning device of the invention incorporates a second or push pawl 12 which is pivotally toggled in relation to said drive pinion 9 by way of a cam plate 13. The cam plate is, itself, freely pivotable about the central axle 6 and incorporates the push pawl by way of pivotal attachment at its free end such that the push pawl is movable about the axle of the drive pinion at a constant distance from MAW:PP:#23988.CAP 2 December 1997 the teeth of the drive pinion. The push pawl is spring activated such that rotation of the cam plate in a first direction by activation of the piston 18 causes the push pawl to engage the drive pinion and urge the drive pinion and associated uptake spool to rotate in the uptake direction.

The action of the push pawl is intended as an incremental adjustment of the load tension and not as the primary winding or tensioning mechanism. The activation of the drive pinion 9 is effected by a piston 18 which is connected with a power system of the vehicle. The power system of the vehicle is preferably a pneumatic or air hose connection to said vehicle which can be operated periodically, preferably every 30 seconds, such that by pulsing said pneumatic system, the piston can be caused to move forward and rotate the cam plate in said first direction thereby moving the push pawl to engage the drive pinion and progresses it forward to automatically tension the load securing means. Upon release of the piston, the push pawl will move in the reverse direction and if sufficient movement has occurred in the first direction, the pawl will traverse a tooth on the drive pinion.

.i Alternatively, if insufficient movement has occurred the pawl will remain in the same position on the drive pinion. In this manner, the push pawl and first pawl ao combine to ensure that the drive pinion and uptake spool do not move in the reverse or unwinding direction and allow the load securing means to loosen or become 20 lacking in tension even if the pneumatic system and hoses of the said vehicle are *e damaged or ruptured during movement. The periodic activation of the pneumatics and operation of a piston, ensures that the load tensioning device of the invention is automatically held in tension so as to take up any slack or compliance that might occur in the load securing means, either by movement of the load during transit or any stretching of the load securing means. In order to ensure that the routine and periodic activation of the uptake spool does not over tension the load securing device, the drive pinion teeth are preferably dimensioned to ensure that any given automatic progression of the drive pinion can only be accomplished if a certain quantum of slack or movement is available in the drive pinion that thereby requires tensioning. In this manner, the load tensioning device of the invention is prevented MAW:PP:#23988.CAP 2 December 1997 -6from overtightening the load securing means by way of a progressive creep of the mechanism.

Referring now to Figure 3, a front view of the device shows the housing comprising the ratchet and pull mechanisms in a closed self-lubricating and low maintenance enclosure. The uptake spool is fully supported from the housing and is provided with a crank 8 for manual operation.

In use, a vehicle or trailer would be fitted with a plurality of the load tensioning devices along the side of the trailer and when the vehicle is suitably loaded, the uptake spools would be released and a load securing straps would be unwound, thrown over the load and secured to the other side of the trailer and then the crank 8 would be manually operated to bring the uptake spool and load securing straps into tension and they would be held in tension by the lock pawl. When all of the load tensioning devices are secured, the vehicle would be ready to drive away and the load securing tensioning devices would be pneumatically connected to the 15 power system by way of suitable air hoses or the system could be permanently .i connected to said power system such that when the vehicle is driven away, a periodic timing device of some description or a manual operation of the pneumatic o•Os system will cause the pistons to periodically activate, for example, every 30 seconds, to ensure that any slackening of the load securing straps which would reveal itself 20 in the ability of a push pawl to move the drive pinion forward at least one quantum I equal to the distance provided by the drive pinion teeth, at which stage the lock pawl would ensure that the drive pinion does not move back. At that point, the load "would be suitably secured and at the next interval, the action would be repeated and if no slacking had occurred in a given load securing strap, the activation of the piston would move the push pawl to the operational position but the movement would not be sufficient to move the push pawl past one quantum or over a particular drive pinion tooth indicating that the load tensioning means was in suitable tension and did not require any further tension. Upon release of the piston, the push pawl would move back to its original position without requiring any advance. In this manner, the invention provides for the first time a highly reliable, low maintenance MAW:PP:#23988.CAP 2 December 1997 -7load tensioning device which incorporates the usual manual operations of such a device with the unique automatic features of the device which ensures that such loads are held in tension to improve the safety operations of said vehicles.

MAW:PP:#23988.CAP 2 December 1997

Claims (8)

1. A load tensioning device including a winding means for fitting to a vehicle, said winding means having an uptake spool for holding a length of load securing means, said uptake spool being capable of unidirectional or non-return rotation characterised in that said uptake spool can be automatically operated in said unidirection by co-operation with the power systems of said vehicle to periodically tighten or tension said uptake spool and securing means, whilst said vehicle is operational or in transit.

2. A load tensioning device according to claim 1 wherein the winding means includes a housing adapted for fitting to said vehicle with said uptake spool rotatably mounted onto said housing via a transverse axle passing through said housing.

3. A load tensioning device according to claim 2 wherein said transverse axle includes a fixed toothed drive pinion and a floating cam plate having a push pawl fitted thereto and adapted to co-operate with said pinion to effect said automatic operation of said uptake spool.

4. A load tensioning device according to claim 3 wherein said push pawl is activated automatically by co-operation with the power systems of said vehicle to urge said uptake spool to periodically rotate in said unidirection to ensure that 20 tension is maintained on said uptake spool.

A load tensioning device according to claims 3 or 4 including a lock pawl adapted to co-operate with said drive pinion to ensure said unidirectional rotation.

6. A load tensioning device according to any one of claims 3 to 5 wherein said drive pinion has about 24 teeth.

7. A load tensioning device for fitting to a vehicle including a winding means and an uptake spool for holding a length of load securing means wherein said winding means includes a traverse axle onto which is mounted said uptake spool characterised in that said transverse axle has a toothed drive pinion fitted thereto and a floating cam plate, the floating cam plate having a push pawl fitted to the free end 2 December 1997 MAW:PP:#23988.CAP -9- thereof and adapted to co-operate with said drive pinion to effect the rotation of said transverse axle wherein the transverse axle can be manually rotated to initially tighten said load securing means and subsequently automatically tightened by the periodic activation of said floating cam plate and push pawl.

8. A load tensioning device according to any one of claims 1 to 7 substantially as hereinbefore described. DATED: 2 December 1997 CARTER SMITH BEADLE Patent Attorneys for the Applicant: BLACKWOOD ENGINEERING PTY LTD o ,f o MAW:PP:#23988.CAP 2 December 1997