GB2401087A

GB2401087A - Load cover

Info

Publication number: GB2401087A
Application number: GB0310153A
Authority: GB
Inventors: George Robert Boden
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-05-02
Filing date: 2003-05-02
Publication date: 2004-11-03
Anticipated expiration: 2023-05-02
Also published as: GB0310153D0; GB2401087B

Abstract

A load cover, particularly for a tipping lorry body, is disclosed. The cover comprises a flexible sheet (12), and a deployment system. The deployment system is operable to move the cover from a deployed condition in which it covers a load container and a withdrawn condition in which it allows access to the load container. The deployment system comprises an arm (50) for mounting on a vehicle to pivot about an axis longitudinal of the vehicle, a roller carried on the pivotable arm (50), and a drive mechanism (66) carried on the pivotable arm. The drive mechanism operable to drive the roller for rotation. The sheet is secured to the roller and to a fixed part of the vehicle. The pivotable the arm is biassed by a spring to move the sheet towards the deployed position. Upon operation of the drive mechanism, the sheet is wound onto the roller and is thereby caused to withdraw from the load container.

Description

Load cover This invention relates to a load cover for a cargo in a cargo

container. It has particular, but not exclusive, application to cover a load in a road vehicle with a tipping body, and non- limiting examples of such application will be described. It might also have application to other cargo-carrying vehicles, including rail vehicles, or static load containers.

When a tipper lorry is used to carry a cargo, it is common to cover the cargo bay of the lorry with a cover of flexible sheet material. The principal purpose of such a cover is to prevent the load from being blown out of the vehicle when it is underway. In their most basic form, such systems require a cover to be deployed manually. However, it is common (and becoming ever more so) to provide a deployment system whereby the cover can be deployed automatically.

While various deployment systems have already been proposed, these have not been without associated problems. Most particularly, such systems are complex and expensive to manufacture and install. An aim of this invention is to provide an automatic deployment system that is at least as effective as known systems, yet which is comparatively simpler and less expensive to install.

Form a first aspect, the invention provides a load cover comprising: À a flexible sheet, and À a deployment system being operable to move the cover from a deployed condition in which it covers a load container and a withdrawn condition in which it allows access to the load container, the deployment system comprising: À a pivotable arm for mounting on a vehicle, a roller carried on the pivotable arm, and À a drive mechanism carried on the pivotable arm and operable to drive the roller for rotation; À the sheet being secured, at a first region, to the roller and at a remote region to a fixed part of the vehicle; and the pivotable the arm being biassed to move the sheet towards the deployed position; and À upon operation of the drive mechanism, the sheet is wound onto the roller and is thereby caused to withdraw from the load container.

Such a system can be implemented readily, particularly because the drive mechanism need operate to move the sheet in one direction only (to withdraw it) movement in the opposite direction being achieved by the biassed arm.

The plane in which the arm can pivot is advantageously substantially vertical. This ensures that the sheet is moved well clear of the load during deployment and withdrawal.

The drive mechanism may advantageously include an electric motor and a (reduction) gearbox that operatively connects the motor to the roller. Most advantageously, the gearbox substantially prevents rotation of the roller other than by rotation of the motor (for instance, it may incorporate a worm and nut drive). This avoids the need to provide a brake to stop unintentional movement of the roller.

In a typical embodiment, the roller is carried between two arms that are pivotable in parallel planes. In many such embodiments, just one arm may carry a drive mechanism, the other carrying a bearing for supporting an opposite end part of the roller.

In a convenient configuration, the arm is biassed by a spring. This may advantageously be contained within the arm itself, where it is unlikely to suffer damage.

From another aspect, and at its most general, this invention provides a deployment system for a load cover, the load cover comprising a flexible sheet, and the deployment system being operable to move the cover from a deployed position in which it covers a load container and a withdrawn position in which it allows access to the load container, the deployment system comprising biassing means for moving the cover towards the deployed condition, and a withdrawal mechanism for withdrawing the cover against the action of the biassing means.

An embodiment of the invention will now be described in detail, by way of example, and with reference to the accompanying drawings, in which: Figure l is a side view of a road lorry with a tipper body including a cover embodying the invention; Figures 2 and 3 are cross-sectional views respectively in the direction of arrows A-A and B-B in Figure 1; Figures 4a and 4b are part-sectional views of a powered arm assembly being a component of the embodiment of the invention; and Figures Sa and Sb are part-sectional views of an non-powered arm assembly being a component of the embodiment of the invention.

The embodiment is applied to a conventional motor road lorry with a tipping body. Such vehicles are typically used to carry heavy particulate material such as quarried products. The body comprises a large box-like container 10 that is upwardly open. The container can be raised at its forward end to pivot about a rear transverse axis to tip the load rearwards from the container through an operable tailboard. Since this much is conventional, it will not be described further.

In order to prevent loss of the material, with potential risk to other road users and environmental contamination, a load cover is provided that can be deployed to cover the load in the container. The load cover can be withdrawn to allow loading or unloading of the material through the top of the container.

The cover of this embodiment includes a sheet 12 of tough, flexible material, such a s a vinyl covered fabric. Several longitudinal pockets 16 (in this case two of them) extend the length of the sheet 12, parallel to one another and approximately equally spaced across the sheet 12.

Each pocket 16 forms a longitudinal tubular formation of flexible material. Within each pocket, a stiffening support member is contained, in this embodiment, formed from a tube 18 of metal.

Upper edges of front and rear walls of the container 10 carry respective support pieces 14.

Each support piece 14 has a lower surface that is in contact with the upper surface of the wall, and an upper surface that has a convex upper curve. When the sheet 12 is deployed to cover the container 10, end portions of the sheet 12 are supported on the upper surfaces of the support pieces 14. The tubes 18 serve to support the sheet 12 above the load along the length of the container 10.

When deployed, the sheet 12 covers the top of the container 10, while when withdrawn, it is S disposed to one longitudinal side of the container 10. The deployment mechanism by which this can be achieved will now be described.

The deployment mechanism comprises a driving arm assembly, shown in Figures 4a and 4b, a non-powered arm assembly 5a and Sb, and a roller extending between the arm assemblies.

Each arm assembly comprises a mounting plate 30 that is secured to a respective end wall of the container 10. Each mounting plate 30 is secured against a respective one of the support pieces 14 such that it is centred upon a fore-and-aft centre line of the container 10. The mounting plates 30 are carried on outer surfaces of the support pieces 14 - that is to say, on the surface that faces away from the load space.

A respective spigot 32 projects from each mounting plate 30. The spigots 32 of the two plates 30 extend, along a common axis, so as to project away from the container 10. Carried on each spigot is an inner bearing 34 and an outer bearing 36, each having an inner race fixed to the spigot 32 and an outer race that is free to rotate about the spigot 30. Between the inner and outer bearings 34, 36 there is a cable pulley 38 fixed upon the spigot such that it cannot rotate or otherwise move. The cable pulley 38 has a generally circular cross-section, with an outer surface in which is formed a groove to receive a cable 40. A cable clamp 42 is provided on the pulley 38 to clamp the cable, close to one of its ends. From the clamp 42, the cable extends though the pulley 38 into the groove.

An inner arm SO of metal box section is carried on the inner and outer bearings 34, 36, such that can rotate about the axis of the spigot 32. An inner end portion of the inner arm 50 is formed from two parallel side walls, each one of which is carried on a respective one of the bearings.

An outer portion of the inner arm 50 is formed as a complete box section with parallel side walls and parallel top and bottom walls. A helical tension spring 52 is contained within the outer portion. An L-shaped bracket 54 is carried at the outer end of the inner arm 50, one plate portion of the bracket closing the outer end of the box section. A threaded bar 56 passes through this plate and is secured there by a nut 58. The threaded bar 56 also has a loop portion that provides an anchorage for one end hook of the tension spring 52. At its opposite end, the tension spring 52 has a hook portion that is connected to a loop formed by the end portion of the cable 40. A cable guide 44 is disposed within the inner arm SO to S guide the cable 40 when it is being wound onto the pulley 38, as will be described in due course.

As thus far described, the driving arm assembly and the non-powered arm assembly are identically constructed. The differences lie in outer arm components that are carried on the bracket 54.

In the case of the non-powered arm assembly, a mounting plate 60 is carried on the bracket 54 to extend radially away from the inner arm portion. A bearing 62 is carried on the mounting plate 60, the bearing being suitable to receive an end portion of a shaft for rotation about an axis parallel to the spigot 32. The connection between the mounting plate 60 and the bracket 54 is by way of bolts 46 that pass through slots through the components. This IS allows the distance between the bearing 62 and the spigot to be adjusted prior to being secured by the bolts being tightened.

In the case of the powered arm assembly, a mounting plate 64 is carried on the bracket 54 to extend radially away from the inner arm portion, the connection between these components being such as described above. A drive unit 66 is carried on the mounting plate, the function of which will be described in due course.

Consider now the arms in the position shown in unbroken lines in Figures 2 and 3 and in Figures 4a and Sa (referred to as the "deployed position"). The length of the spring 52, cable and the position of the nut 58 on the threaded bar 56 is selected such that the spring 52 is under some light tension. Now, if the arm is rotated about the spigot 52 in a clockwise direction (in Figures 4a and Sa), the cable 40 is wound around the pulley 38, effectively shortening its length. This increases the tension in the spring 52. Tension is greatest when the arm is rotated to its furthest limit - by approximately 180 - to what will be referred to as the "withdrawn position", as shown in dotted lines in Figures 2 and 3. Thus, the arm is, at all times, urged by the action of the spring towards the deployed position. This is important to further understanding of the operation of the system.

A roller 70, being an elongate metal bar of circular cross section extends between the bearing 62 of the non-powered arm and the drive unit 66 on the powered arm assembly. The drive unit 66 includes an electric motor connected through a reduction gearbox to the roller 70.

The gearbox is configured such that the motor cannot be driven by rotation of the roller, such that the roller can be turned only by the motor and not be directly applied rotational force.

One long edge portion of the sheet 12 is secured along the length of the roller 70. The opposite long edge of the sheet 12 (referred to as the "fixed edge") is secured along the edge of the load container 10. The arrangement is such that the spring action of the arms, described above, is such as to urge the roller away from the fixed edge of the sheet.

Consider now the situation in which the arms are in the deployed position. The sheet 12 covers the load as described above. The sheet 12 is maintained in place by the spring action of the arms, and is secured by straps 72 that extend between the roller 70 and a fixed part of the vehicle body. To withdraw the cover, the straps 72 are first released. An electric supply is then connected to the drive unit 66, causing the roller 70 to rotate in a first, winding direction. When this happens, the sheet 12 is wound onto the roller. Since the fixed edge of the sheet cannot move, the roller 70 must move. The only path that the roller 70 can follow is an arc as the arms pivot. This movement can continue until the arms reach the withdrawn position. The spring action of the arms maintain tension in the sheet 12 throughout. The support tubes 18 are dimensioned to be sufficiently small that they are simply rolled up with the rest of the sheet 12.

To deploy the sheet 12, the direction of the roller is reversed. This causes the sheet to unroll from the toiler 70. Once again, the spring action of the arms maintain the sheet 12 in tension until the arms reach the deployed position. The straps 72 can then be re-applied.

This embodiment requires only a simple control system. A power supply must be provided to drive the motor in both directions, and there must be controllable from a switch, typically in the vehicle cab. In addition, it is preferable to provide limit switches to prevent the arms from moving beyond the limits of their travel. All of these systems can be provided readily and without substantial modification to the vehicle. Wires to carry current to the drive unit are not shown in the drawings for clarity, but can straightforwardly be fed along the pivotable arm.

Claims

Claims 1. A load cover comprising:a flexible sheet, and a deployment

system being operable to move the cover from a deployed condition in which it covers a load container and a withdrawn condition in which it allows access to the load container, the deployment system comprising: a pivotable arm for mounting on a vehicle, a roller carried on the pivotable arm, and a drive mechanism carried on the pivotable arm and operable to drive the roller for rotation; the sheet being secured, at a first region, to the roller and at a remote region to a fixed part of the vehicle; and the pivotable the arm being biassed to move the sheet towards the deployed position; and upon operation of the drive mechanism, the sheet is wound onto the roller and is thereby caused to withdraw from the load container.
2. A load cover according to claim 1 in which the arm can pivot in a plane that is substantially vertical.
3. A load cover according to claim 1 or claim 2 in which the drive mechanism includes an electric motor and a gearbox that operatively connects the motor to the roller.
4. A load cover according to claim 3 in which the gearbox substantially prevents rotation of the roller other than by rotation of the motor.
5. A load cover according to any preceding claim in which the roller is carried between two arms that are pivotable in parallel planes.
6. A load cover according to claim 5 in which just one arm carries a drive mechanism, the other carrying a bearing for supporting an opposite end part of the roller.
7. A load cover according to any preceding claim in which the arm is biassed by a spring.
8. A load cover according to claim 7 in which the spring is located within the arm itself.
9. A load cover substantially as herein described with reference to the accompanying drawings.

lO.A deployment system for a load cover, the load cover comprising a flexible sheet, and the deployment system being operable to move the cover from a deployed position in which it covers a load container and a withdrawn position in which it allows access to the load container, the deployment system comprising biassing means for moving the cover towards the deployed condition, and a withdrawal mechanism for withdrawing the cover against the action of the biassing means.