GB2299311A

GB2299311A - Air bag roof lifting mechanism for motor vehicles

Info

Publication number: GB2299311A
Application number: GB9606589A
Authority: GB
Inventors: James Ronald Cramp
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-03-28
Filing date: 1996-03-28
Publication date: 1996-10-02
Anticipated expiration: 2016-03-28
Also published as: GB9506259D0; GB9606589D0; GB2299311B

Abstract

The roof 12 is liftable by up to fifty centimetres to allow access to loads which would otherwise be obstructed by the depending border 16 of the roof. The lifting mechanism comprises at least one air bag 20 and scissor linkage 21 at each end of the vehicle. The air line to each air bag 20 may be incorporated in the front or rear wall or in the frame uprights. The source of compressed air may be reservoir tanks fed by the vehicle's compressor or a compressed air bottle. The vehicle may be a curtain-sided trailer.

Description

ROOF LIFTING MECHANISM FOR A VEHICLE This invention relates to load-carrying vehicles, in particular to a system for lifting the roof of such a vehicle.

In the present application, the word vehicle is to be understood as including both self-propelled vehicles and trailers.

Many goods vehicles have a load bearing surface which is loaded from the side, and which have a roof supported on frames at least at the front and rear of the vehicle. Since the roof usually has downwardly projecting borders, which for example cover a curtain track in curtain-sided vehicles, this border forms an obstruction when loading articles which would only just fit beneath the roof itself. Many vehicles therefore have systems which will lift the roof by an amount equivalent to the depth of the border.

Known lifting mechanisms include hydraulic or pneumatic cylinders, mechanical pushrods and linkage systems1 and the like. The drive mechanism or drive system is often positioned beneath the load bearing surface and has to be connected to the roof by transmissions or linkages which extend up the corner posts of the frames at the front and. rear. These systems are cumbersome and prone to damage and jamming, can often raise the roof unevenly, and if they fail can allow the roof to collapse. It is an objective of this invention to reduce or overcome at least some of these disadvantages.

Accordingly, the invention proposes that lifting means for the roof should comprise flexible air bags which are located between the roof and the respective frames at the front and rear.

Only a single pneumatic supply line is needed at one corner of one frame, leading to a pressure generator in any desired position on the vehicle.

In order that the invention shall be clearly understood, an exemplary embodiment thereof will now be described with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of the rear of a vehicle; Figure 2 shows a view to a larger scale of a top corner of the vehicle body from the rear; Figure 3 shows a section through an installed air bag in its deflated condition; and Figure 4 shows a view similar to Figure 3 with the air bag inflated.

Figure 1 shows the rear end of a self-propelled vehicle, or a trailer, having a load-carrying surface 10, a rear frame 11 and a roof 12. A front frame (which may be the vehicle cab) supporting the other end of the roof is not shown. The frame 11 comprises uprights 13 and a transverse beam 14. Within the frame, the area 15 may be permanently covered by a panel or may include opening doors. The long sides of the load bearing surface 10 may have any desired movable wall, such as curtaining (not shown), which can be moved aside in order to allow goods to be loaded from the side.

The roof 12 spans the whole load bearing surface 10, being supported at least on the rear frame 11 and the corresponding front frame but it may also have supports at other points along its length. The roof has a depending border 16 which represents an obstruction to loading goods which would otherwise fit under the flat surface. The roof. however, not rigidly fixed since for the purpose of loading goods it is movable upwards by up to twenty inches. There is therefore provided a lifting mechanism which lies between the cross-beam 14 and the end structure of the roof 12.

This lifting mechanism at each end of the roof comprises an air bag 20 and two mechanical linkage mechanisms 21. The linkage mechanisms 21 consist of scissor-devices which do not strictly support the roof 12 but form stabilising elements to control movement of the roof and in particular to restrain undue upward movement of the roof which might otherwise arise from wind forces.

A similar lifting arrangement is provided at the front end of the load space (not shown).

Figure 2 shows the arrangement in greater detail. The air bag 20 is shown inflated, thus pushing the roof 12 upwards in relation to the transverse bar 14 upon which it rests. The air bag 20 may be of any appropriate size, but preferably extends across approximately the middle one third of the total width of the back of the vehicle. However, there might be more than one air bag provided, for example towards each side of the vehicle. The air bag may be of any suitable form, and may include various control and safety features, for example so that if one compartment of the bag were punctured, this would not cause collapse, thus ensuring that the roof would remain in its lifted position.

Preferably. the bag has a length of approximately 1.6 metres and a width of about 32 cms. When deflated, it has a thickness of only a few centimetres, but can be inflated to a height of 25-30 centimetres.

The cross-section on the line 3-3 in Figure 2 is shown in Figure 3. with the bag inflated in both cases.

As seen in Figures 3 and 4, the main longitudinal roof frame 22 moves vertically by the distance H, which is preferably between 10 and 20 inches. In the raised position. the roof trim or border 16 is moved sufficiently out of the way to allow loads to be placed from the side onto the load bearing surface 10 without damage to the load or to the border 16. Atter the load has been put in place, the roof can then be lowered back to the position shown in Figure 4. The roof does not need to be locked in either its raised or its lowered position.

The airbag can be made of any suitable material e.g. coated nylon or 'Kevlar' (RTM), with any desired number of compartments. Each airbag requires only a single air line which can be incorporated within the front or rear wall, or in one of the frame uprights. The source of compressed air (air reservoir tanks fed by the vehicle compressor, or a compressed air bottle) can be located anywhere convenient below the load bearing surface.

Claims

1. A load-carrying vehicle having a load-carrying surface (10) covered by a roof (12) supported on frames (11) at least at the front and rear of said surface, said roof being movable between a lowered and a raised condition, having lifting means (20) for this purpose which comprise a flexible fluid-pressure bag located between the roof and the respective frame at the front and rear.

2. A vehicle as defined in claim 1 wherein the frame at the front is formed by the vehicle cab.

3. A vehicle as defined in claim 1 or 2 wherein the fluid is air.

4. A vehicle as defined in claim 1, 2 or 3 wherein said bags are connected to a source of fluid pressure mounted below the load-carrying surface, or elsewhere on or in the vehicle cab.

5. A vehicle as defined in claim 4 wherein a single fluid pressure line extends from the source to the bags up a support frame at the front or rear.

6. A vehicle as defined in any preceding claim wherein the roof is mechanically linked to the respective frame by a collapsible linkage.

7. A vehicle as defined in claim 6 wherein the linkage is a pantograph or an X-shaped framework.

8. A vehicle as defined in any preceding claim wherein the fluid pressure bags are divided internally into a number of separate chambers.

9. A load-carrying vehicle substantially as herein described with reference to the accompanying drawings.