GB2288581A - Load covers for long vehicles - Google Patents

Abstract

A mechanism for deploying a cover (12) over the upper surface of a container situated on the load bed of a vehicle comprises a pair of upstanding arms (9), optionally of variable length, each arm (9) mounted at its respective lower end to a traveller running in a guide (4) extending along a respective side of the vehicle body, the travellers being moved in unison forwardly and rearwardly of the vehicle by a drive means, the respective upper ends of the arms (9) being joined by a generally horizontally extending bar (10) aligned in the transverse direction with relation to the vehicle, a flexible cover (12) having a length dimension at least equal to the length of the vehicle load bed and a width dimension at least equal to the width of the vehicle load bed having one of its sides attached to the bar (10), and being retractable onto or into a load cover receiving means (11), the arrangement being such that rearward movement of the travellers and the upstanding arms (9) will draw the load cover (12) from the receiving means over the top of the vehicle body. <IMAGE>

Description

LOAD COVERS FOR LONG VEHICLES The present invention relates to load coverings for vehicles, and is particularly concerned with a mechanically-deployed flexible cover for use in connection with open-topped goods vehicles or with goods vehicles carrying open-topped containers.

Various commodities are transported by road in open-topped vehicles or containers, and in order to prevent any loss of the load it is known to deploy a flexible covering sheet over the open upper face of the container when it is in place on a vehicle. In a conventional arrangement for so doing, a flexible cover is rolled onto a horizontally-extending roller situated between the forward end of the container and the rear of the driving compartment. The free edge of the rolled cover is attached to a horizontally-extending bar which is mounted to the free ends of a pair of swinging arms secured to the vehicle body at approximately the mid-point of the longitudinal extent of the load bed. By pivoting these arms to the rear of the vehicle, the flexible sheet is drawn off the roller and is deployed over the top of a container situated on the vehicle load bed.

A disadvantage of the equipment is that, when the vehicle body is very long, the pivoting arms must necessarily be long in order to reach from the front of the vehicle to the rear. This can cause mechanical problems of stiffness and weight in the arms, and also requires excessive clearances above the vehicle during deploying and retracting the load cover.

It is an object of the present invention to provide a vehicle load covering mechanism capable of deploying and retrieving a cover over a long open-topped vehicle body, without the use of inconveniently long arms.

According to the present invention, a mechanism for deploying a cover over the upper surface of a container situated on the load bed of a vehicle comprises a pair of upstanding arms each mounted at its respective lower end to a traveller running in a guide extending along a respective side of the vehicle body, the travellers being moved in unison forwardly and rearwardly of the vehicle by a drive means, the respective upper ends of the arms being joined by a generally horizontally extending bar aligned in the transverse direction with relation to the vehicle, a flexible cover having a length dimension at least equal to the length of the vehicle load bed and a width dimension at least equal to the width of the vehicle load bed having one of its sides attached to the bar, and being retractable onto or into a load cover receiving means situated adjacent the forward end of the vehicle load bed, the arrangement being such that rearward movement of the travellers and the upstanding arms will draw the load cover from the receiving means over the top of the vehicle body.

In the preferred embodiment, the guides are outwardly-facing channel sections fixed along the sides of the vehicle chassis or body, and the travellers are supported in the guides on rollers to prevent relative rotation of the travellers and the guides. The end portions of the guides may, however, be inclined or curved downwardly so as to cause the travellers, and hence the upstanding arms, to rotate about a horizontal transverse axis to incline the upstanding arms towards the adjacent end of the vehicle body. This will allow the guides to be significantly shorter than the vehicle body, and provides for a clearance between the upper ends of the arms and the top of the vehicle body when the arms are in generally vertical orientation.

Preferably, the movement of the travellers is achieved by means of hydraulic or pneumatic piston and cylinder arrangements mounted at the ends of the guides and acting between the respective travellers and the vehicle body.

In an alternative arrangement, the travellers may be connected to one or more endless chains running over sprockets placed at the ends of the guides to draw the travellers forwards and backwards in the guides. The chains may be driven by hydraulic or electric motors, or by hydraulic or pneumatic rams.

In a further alternative embodiment, the upstanding arms may be also mounted for translational movement in the transverse direction of the vehicle so as to alter the spacing between the upstanding arms. The bar joining the upper ends of the swinging arms may be made telescopic, so that its length may be varied to adjust the spacing between the swinging arms.

An embodiment of the invention will now be described in detail with reference to the accompanying drawing, in which: Figure 1 is a schematic side view of a vehicle fitted with a flexible load cover deploying mechanism; and Figure 2 is a schematic view,to an enlarged scale, of a traveller.

Referring now to the Figures, there is seen a vehicle having a chassis 1 and a driving compartment 2 situated at its forward end. The rear of the chassis 1 supports a body 3. It should be understood that the vehicle may be a fixed-body type with an open-topped body structure, or may be a swap-body type capable of accepting demountable containers on a load bed. The vehicle may have a tipping capability.

Extending along the central part of the main chassis members, intermediate the longitudinal extent of the load bed, are a pair of guide channels 4. The guide channels 4 are generally horizontal, and have downwardly curved front and rear end portions 5 and 6. A traveller 7, best seen in Figure 2, is received in each of the guides 4, the traveller having a pair of rollers 8 engaging the guide 4 to prevent rotation of the traveller 7 in the guide 4 about axes parallel to the axes of the rollers 8.

Each traveller 7 has rigidly fixed thereto the lower end of an upstanding arm 9, the arms 9 being joined at their upper ends by a transverse bar 10.

Drive means (not shown) are provided to move the travellers 7 forward and back along the guides 4. The drive means may be formed by piston and cylinder assemblies with the cylinder fixed to the vehicle chassis and the piston fixed to the traveller. Alternatively, a pair of transverse shafts may support sprockets adjacent the front and rear ends 5,6 of the guides, and each traveller may be fixed to a point on an endless chain passing round the sprockets adjacent the ends of one guide, so that rotation of the shafts can cause movement of the travellers 7 forward and back along the guides 4.

Mounted to the vehicle chassis between the driving compartment 2 and the forward end of the body 3 is a load cover receiving means 11 which in the embodiment shown comprises a transversely extending shaft onto which a flexible load cover sheet 12 is rolled. To attach the load cover sheet 12 to the shaft, the shaft may be formed with an undercut channel groove along its length to accept a thickened edge portion of the load cover sheet. Such a thickened edge portion may be formed by a boltrope attached to the edge of the load cover sheet. The transversely extending edge of the cover sheet 8 remote from the load cover receiving means 11 is attached to the central part of the transverse bar 10, preferably by means of a second boltrope received in an undercut channel groove in the central part of transverse bar 10. Clearly, however, any other fixing means may be used, such as a clamping bar extending along the edge of the load cover sheet and fixed to the transverse bar to clamp the load cover sheet therebetween, or a series of discreet fixings such as flanged bolts or screws.

The load cover sheet 12 may be a slightly elastic membrane, or a mesh of elastic filaments.

The load cover receiving means 11 may be mounted to the chassis 1 in such a way that the vertical height of the load cover receiving means above the chassis 1 can be varied. Advantageously, the load cover receiving means 11 can be positioned so as to be adjacent the forward upper edge of the vehicle body 3.

The procedure for covering the body will now be described with reference to the Figures.

In the uncovered state, the travellers 7 and the upstanding arms 9 are moved forward, with the load cover sheet 12 coiled on, or otherwise stowed in or on, the load cover receiving means 11.

In order to deploy the flexible load cover over the top of the body, the travellers 7 and the upstanding arms 9, actuated preferably either hydraulically or by pneumatic means, spring means, or electrically driven means, are moved rearwards along the guides 4 so that the transverse bar 10 moves rearwardly over the body 3 to a position beyond the rear upper edge of the body. Due to the downturned end portions 4 and 6 of the guides 4, the upstanding arms 9 first rotate clockwise to a substantially vertical position, then move rearwards, and finally rotate clockwise to an inclined position as seen in Figure 1.

During the movement, the upper ends of the upstanding arms 9 are spaced from the upper edge of the vehicle body-3 to provide clearance between the load cover sheet 12 and the body 3.

The flexible load cover 12, which is attached to the transverse bar 10, is during this time drawn across the open upper surface of the body 3, effectively sealing it.

The vehicle is now ready to be driven to its unloading station.

At the unloading station, the travellers 7 are moved forwards to the front ends 5 of the guides 4, causing the upstanding arms 9 to first rotate anticlockwise to a vertical position and then to move forwards, and finally to rotate again anticlockwise to their final, inclined, position. During this movement, the flexible load cover sheet 12 is wound onto the load cover sheet receiving means 11. When the upstanding arms 5 have reached their forwardmost position, the body is uncovered and can then be tipped or unloaded in the conventional manner. If the vehicle is to be driven to a new location prior to reloading, the body 3 may be left uncovered.

In an advantageous development of the invention (not illustrated), the side edges of the vehicle load cover may be brought into closer engagement with the top of the load by providing a pair of tension elements running along the sides of the load cover, preferably extending from points near the upper ends of upstanding arms 9 to the sheet receiving means 11. The tension elements may be ropes or cables, or may be elastic or have elasticated portions incorporated therein. The tension elements may pass through sleeves formed at the edges of the load cover, or may be attached thereto along their lengths at various points.

In this advantageous embodiment, the transverse dimension of the load cover is greater than the width of the top of the vehicle body, to provide an overhang extending down the sides of the vehicle body. The edges of the load cover are each provided with a series of eyelets through which a rope is passed in alternating directions relative to the plane of the load cover. One end of these ropes is attached to the shaft on which the load cover is rolled up, and the other end is lead through a fairlead situated on one of the upstanding arms 9 at a point spaced from its upper end, and from there passes to a tensioner mounted on the upstanding arm 9. The tensioner may be a manual or powered winch, a spring-driven drum, or other similar device. The lengths of the ropes are so arranged that when the upstanding arms 9 are pivoted to their rearmost positions, the ropes lie below the top to the body and pull the load cover sheet into tight engagement with the body top.

While the embodiment shown has the guides fixed on the vehicle chassis, it will be understood that the guides 4 could be mounted higher up on the body 3, in order to allow shorter arms 9 to be used. Likewise, the load cover arrangement described can be used with swap-body vehicles as well as fixed-body types.

Alternatively, the load cover receiving means 11 may be mounted between the upper ends of the arms 9, and may provide for the rolling and unrolling of the load cover around the transverse bar 10. In such an arrangement, as the upstanding arms 9 are pivoted to their rearmost positions, the load cover will be unrolled to lie over the open top of the vehicle body. As will be appreciated, when the upstanding arms 9 are moved forwards to their final, inclined, position, the load cover receiving means 11 will roll up the cover sheet as the transverse bar 10 moves forward. This arrangement largely avoids relative movement of the load cover over the load in the body, and reduces damage to the load cover that jagged loads may cause.

Clearly, when the load cover receiving means 11 is mounted between the upper ends of the arms 9, and the edges of the load cover are each provided with a sleeve or a series of eyelets through which a tensioning rope is passed, an end of each tensioning rope will be fixed at the load cover receiving means 11. To provide for tightening of the ropes when the cover is deployed, winches are provided at the front end of the load, the ropes being led through fairleads at the forward end of the load cover and thence to the tensioning winches. The winches may be placed at a convenient height for manual operation, or may be motorised and placed in any location up to the height of the open body top. The winches may be driven from a common shaft, enabling manual operation of both winches from the same operator position, or simultaneous motor operation using a single motor. The ropes may be of any suitable material, such as natural or synthetic fibre, synthetic monofilament, or metallic wire.

In a further advantageous embodiment, not illustrated, the effective length of the upstanding arms is made adjustable so that the transverse bar can perform a linear movement along the top of the container or vehicle body. This is achieved by reducing the effective length of the arms as the arms approach their vertical positions, and increasing the effective length of the arms as the arms move away from the vertical.

The upstanding arms may be telescopic, or alternatively the upstanding arms may be formed by first and second pivotally connected arm segments, the first arm segments being attached to the travellers and the second arm segments being attached to the bar, so that relative pivoting of the first and second arm segments alters the effective length of the arms, i.e. the distance between the travellers and the bar. The effective length of the arms may be adjustable, even in embodiments where the load cover receiving means is mounted between the upper ends of the arms.

The alteration of the effective length of the arms may be achieved by means of electric or hydraulic actuators, or by a mechanical linkage controlling the locus of the upper ends of the arms as the arms move from end to end of the load.

Claims (15)

1. A mechanism for deploying a cover over the upper surface of a container situated on the load bed of a vehicle, comprising a pair of upstanding arms each mounted at its respective lower end to a traveller running in a guide extending along a respective side of the vehicle body, the travellers being moved in unison forwardly and rearwardly of the vehicle by a drive means, the respective upper ends of the arms being joined by a generally horizontally extending bar aligned in the transverse direction with relation to the vehicle, a flexible cover having a length dimension at least equal to the length of the vehicle load bed and a width dimension at least equal to the width of the vehicle load bed having one of its sides attached to the bar, and being retractable onto or into a load cover receiving means, the arrangement being such that rearward movement of the travellers and the upstanding arms will draw the load cover from the receiving means over the top of the vehicle body.

2. A mechanism according to claim 1, wherein the load cover receiving means is mounted to the vehicle at a position adjacent the forward end of the vehicle load bed

3. A mechanism according to claim 1, wherein the load cover receiving means is carried between the upper ends of the upstanding arms.

4. A mechanism according to any of Claims 1 to 3, wherein the guides are outwardly-facing channel sections fixed along the sides of the vehicle chassis or body, and the travellers are supported in the guides on rollers to prevent relative rotation of the travellers and the guides.

5. A mechanism according to any preceding Claim, wherein the end portions of the guides are inclined or curved downwardly so as to cause the travellers, and hence the upstanding arms, to rotate about a horizontal transverse axis to incline the upstanding arms towards the adjacent end of the vehicle body.

6. A mechanism according to any of Claims 1 to 5, wherein the travellers are connected to one or more endless chains running over sprockets placed at the ends of the guides to draw the travellers forwards and backwards in the guides.

7. A mechanism according to any of Claims 1 to 5, wherein the movement of the travellers is achieved by means of hydraulic or pneumatic piston and cylinder arrangements mounted at the ends of the guides and acting between the respective travellers and the vehicle body.

8. A mechanism according to any preceding Claim, wherein the upstanding arms are mounted for translational movement in the transverse direction of the vehicle so as to alter the spacing between the upstanding arms.

9. A mechanism according to Claim 8, wherein the bar joining the upper ends of the swinging arms may be made telescopic, so that its length may be varied to adjust the spacing between the swinging arms.

10. A mechanism according to any preceding claim, wherein the effective length of the upstanding arms can be adjusted.

11. A mechanism according to Claim 10, wherein the upstanding arms are telescopic.

12. A mechanism according to Claim 10, wherein the upstanding arms are formed by first and second pivotally connected arm segments, the first arm segments being attached to the travellers and the second arm segments being attached to the bar, relative pivoting of the first and second arm segments altering the distance between the travellers and the bar.

13. A mechanism according to any preceding claim, wherein the transverse dimension of the load cover is greater than the width of the top of the vehicle body, and the longitudinally extending edges of the load cover are each provided with a tensioning element, one end of which is attached to the load cover receiving means, and the other end is lead to a tensioner.

14. A mechanism according to Claim 13, wherein the tensioning element is a rope or the like, and the tensioner is a manually or power-operable winch.

15. A mechanism for deploying a cover over the upper surface of a container situated on the load bed of a vehicle, substantially as herein described with reference to Figure 1 or Figure 2 of the accompanying drawings.