GB2258437A

GB2258437A - Articulated vehicle with swivel locking mechanism.

Info

Publication number: GB2258437A
Application number: GB9117312A
Authority: GB
Inventors: Lawrence Anthony Hawgood
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-08-09
Filing date: 1991-08-09
Publication date: 1993-02-10
Anticipated expiration: 2011-08-09
Also published as: GB2258437B; GB9117312D0

Abstract

The vehicle (2) comprises a first chassis part (4) and a second chassis part (6) able to swivel relative to each other about a fore-and-aft axis for travel over rough terrain and a hydraulic locking mechanism (8) able to lock the first and the second chassis parts (4, 6) together to prevent the swivelling eg when travelling on roads. The swivel joint may be disposed around the propeller shaft 44 of the vehicle. The hydraulic locking mechanism may comprise a ram which can extend through aligned holes in the vehicle parts 4, 6. <IMAGE>

Description

A VEHICLE This invention relates to a vehicle and, more especially, this invention relates to a vehicle which is able to drive on roads and which is also able to drive over rough terrain with surface adhesion on all wheels of the vehicle when the vehicle is being driven over obstacles.

Accordingly, in one non-limiting embodiment of the invention, there is provided a vehicle comprising a first chassis part, a second chassis part, and a hydraulic locking mechanism, the first and the second chassis parts being such that they are able to swivel relative to each other about a vertical plane, and the hydraulic locking mechanism being such that it is able to lock the first and the second chassis parts together to prevent the swivelling.

The relative swivelling of the first and the second chassis parts of the vehicle enables the vehicle to be driven over rough terrain with surface adhesion on all wheels of the vehicle when the vehicle is being driven over obstacles. More specifically, when the vehicle is being driven over obstacles, the wheels of the vehicle can remain in contact with the obstacle and the surrounding terrain whilst the first and the second chassis parts are able to swivel with respect to each other. Thus the first and the second chassis parts are such that, when the vehicle is being driven over rough terrain, the first and the second chassis parts are constantly able to swivel with respect to each other.When the vehicle is being driven on roads, the swivelling facility is no longer needed and the first and the second chassis parts are advantageously locked together by the hydraulic mechanism, thereby preventing danger from unwanted swivelling, for example with high loads or in high torque situations. Also, because of of the hydraulic locking mechanism, the vehicle is able to be driven on roads without convening any road safety regulation by virtue of the swivelling first and the second chassis parts.However, once the vehicle is required to be driven over rough terrain, the hydraulic locking mechanism can be released to allow the first and the second chassis parts to be in a continuously swivellable state so that the vehicle can be driven over very rough terrain with very large obstacles whilst guaranteeing that all the wheels of the vehicle will be in constant contact with the ground.

Usually, the vehicle will only have one hydraulic locking mechanism but it may have two or more hydraulic locking mechanisms if desired.

Preferably, the vehicle is one in which the hydraulic locking mechanism comprises a reservoir for hydraulic fluid, a piston operating in a cylinder, a first conduit connecting the reservoir to a first end portion of the cylinder on a first side of the piston, a second conduit connecting the reservoir to a second end portion of the cylinder on a second side of the piston, and valve means having a first position in which hydraulic fluid from the reservoir can pass to the first and the second conduits, and a second position in which the hydraulic fluid from the reservoir is prevented from passing to the first and the second conduits, the piston being connected to a locking device for locking the first and the second chassis parts together, and the hydraulic locking mechanism being such that the first and the second chassis parts are able to move relative to each other when the valve means in the first position and such that the first and the second chassis parts are locked together when the valve means is in the second position.

The valve means may be a T-piece 3-way valve.

The locking device will usually be a ram device.

The vehicle may include a swivel joint for permitting the relative swivelling of the first and the second chassis parts.

The swivel joints may be a cylindrical swivel joint disposed about a propeller shaft of the vehicle.

Preferably, the swivel joint is located over a front part of the propeller shaft.

The swivel joints may comprise roller bearings.

Advantageously, the vehicle has an engine located between its front and its rear axle, thus creating a low centre of gravity for safe off-road operation. Also advantageously, the vehicle has low pressure tyres and articulated steering, for enabling the vehicle to be driven over grass and field surfaces without damage to the grass and the field surfaces.

The vehicle may be provided with a hydraulic power take-off facility, in order to enable the vehicle to become a power resource in normally remote and inaccessible terrain. Thus the vehicle may be effective to carry loads and tools to and from places where other wheeled vehicles cannot safely get to. With the hydraulic power take-off facility, hydraulic power can be provided if necessary when the vehicle is at its destination.

An embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawings in which: Figure 1 shows a vehicle in the form of a truck being driven over an obstacle; Figure 2 shows schematically how the vehicle comprises first and second swivelling chassis parts; Figure 3 shows in more detail a swivel joint for permitting the swivelling of the first and the second chassis parts; Figure 4 shows a hydraulic locking system in a first position; and Figure 5 shows the hydraulic locking system of Figure 4 in a second position.

Referring to the drawings, there is shown a vehicle 2 comprising a first chassis part 4 and a second chassis part 6. The vehicle 2 also comprises a hydraulic locking mechanism 8.

The first and the second chassis parts 4, 6 are such that they are able to swivel relative to each other about a vertical plane. The hydraulic mechanism 8 is such that it is able to lock the first and the second chassis parts 4, 6 together to prevent the swivelling. Thus, when the vehicle is being driven on a road and the vehicle is required to comply with all road safety regulations, then the hydraulic locking mechanism can be in a locking condition to lock the first and the second chassis parts together to prevent the swivelling. However, when the vehicle is to be driven over rough terrain and it is required to ensure that all four wheels 10 of the vehicle remain in good surface contact with the terrain, then the hydraulic locking mechanism can be released to allow the first and the second chassis parts 4, 6 to swivel as required to allow the wheels 10 to maintain ground contact.

Thus, as shown in Figure 1, the vehicle 2 can drive over a log 12 with all of the wheels 10 in contact with the terrain because the first and the second chassis parts 4, 6 will have swivelled relative to each other to allow the driver's cab 14 to tilt with respect to the rear truck part 16 of the vehicle 2.

As shown in Figures 4 and 5, the hydraulic locking mechanism 8 comprises a reservoir 18 for hydraulic fluid 20. The hydraulic locking mechanism 8 further comprises a piston 22 operating in a cylinder 24. A first conduit 26 connects the reservoir 18 to a first end portion 28 of the cylinder 24 on a first side 30 of the piston 22.

A second conduit 32 connects the reservoir 18 to a second end portion 34 of the cylinder 24 on a second side 36 of the piston 22.

The hydraulic locking mechanism 8 further comprises valve means 38 having a first position in which hydraulic fluid 20 from the reservoir 18 can pass to the first and the second conduits 26, 32 and a second position in which the hydraulic fluid 20 from the reservoir 18 is prevented from passing to the first and the second conduits 26, 32.

The piston 22 is connected to a locking device in the form of a ram device 40 for locking the first and the second chassis parts 4, 6 together.

The hydraulic locking mechanism 8 operates such that the first and the second chassis parts 4, 6 are able to move relatively to each other when the valve means 38 is in its first position as shown in Figure 4. When the valve means is in its second position as shown in Figure 5, then the first and the second chassis parts 4, 6 are locked together. For simplicity of illustration, the piston 22 and the cylinder 24 have been omitted from Figure 5.

As can be seen from Figures 4 and 5, the valve means 38 is a T-piece 3-way valve. Such a valve is extremely simple to operate for locking and unlocking the first and the second chassis parts 4, 6.

During operation, the hydraulic fluid, for example oil, is not under any pressure and it is just acting on both sides 30, 36 of the piston 22. Because the sides 30, 36 of the piston 22 are of different surface areas, an uneven pressure is normally being applied to the piston 22 during use of the vehicle 2 with the hydraulic locking system 8 in its unlocked position. Thus the ram device 40 and its attached piston 22 is able to move backwards and forwards as the vehicle 2 travels over rough terrain and the first and the second parts 4, 6 swivel with respect to each other. When it is desired to lock the first and the second chassis parts 4, 6 together, then the valve means 38 is rotated to the position shown in Figure 5.In this position, the hydraulic fluid cannot move and thus there is a solid hydraulic connection through the first conduit 26 and the second conduit 32 from the valve means 38 to the piston 22. Thus the ram device 40 is able to lock the first and the second chassis parts 4, 6 together.

The swivelling of the first and the second chassis parts 4, 6 is most clearly illustrated in Figures 2 and 3. As can be seen, the vehicle 2 includes a swivel joint 42 for permitting the relative swivelling of the first and the second chassis parts 4, 6. The swivel joint 42 is a cylindrical swivel joint which is disposed about a propeller shaft 44 of the vehicle 2. The swivel joint 42 is located over a front part of the propeller shaft 44, and the swivel joint 42 comprises roller bearings 46.

During operation of the vehicle 2, the first and second chassis parts 4, 6 can be prevented from rotating relative to one another about the swivel joint 42 by the ram device 40 locking the first and the second chassis parts 4, 6 together, for example by passing through aligned holes (not shown) in the first and the second parts 4, 6.

It is to be appreciated that the embodiment of the invention described above with reference to the accompanying drawings has been given by way of example only and that modifications may be effected. Thus, for example, the first and the second parts 4, 6 may pivot with respect to each other by means of a joint other than the illustrated swivel joint 42. Usually, only one hydraulic locking mechanis, 8 will be employed but two or more hydraulic locking mechanisms may be employed if desired. Apart from the hydraulic locking mechanism 8 and the swivel joint 42, the vehicle 2 may be constructed from known standard motor parts. Thus, for example, the vehicle 2 may be provided with disc brakes as appropriate, front and rear differential units, independent suspension, a right angled steering box with appropriate linkage to rack-and-pinion steering, a master brake cylinder and reservoir, a fuel tank, a load carrying platform in the trunk part 16, and a weatherproof safety cab 14. Generally, the vehicle 2 can be of any suitable and appropriate size and construction.

Claims

1. A vehicle comprising a first chassis part, a second chassis part, and a hydraulic locking mechanism, the first and the second chassis parts being such that they are able to swivel relative to each other about a vertical plane, and the hydraulic locking mechanism being such that it is able to lock the first and the second chassis parts together to prevent the swivelling.

2. A vehicle according to claim 1 in which the hydraulic locking mechanism comprises a reservoir for hydraulic fluid, a piston operating in a cylinder, a first conduit connecting the reservoir to a first end portion of the cylinder on a first side of the piston, a second conduit connecting the reservoir to a second end portion of the cylinder on a second side of the piston, and valve means having a first position in which hydraulic fluid from the reservoir can pass to the first and the second conduit, and a second position in which the hydraulic fluid from the reservoir is prevented from passing to the first and the second conduits, the piston being connected to a locking device for locking the first and the second chassis parts together, and the hydraulic locking mechanism being such that the first and the second chassis parts are able to move relative to each other when the valve means is in the first position and such that the first and the second chassis parts are locked together when the valve means is in the second position.

3. A vehicle according to claim 2 in which the valve means is a T-piece 3 - way valve.

4. A vehicle according to claim 2 or claim 3 in which the locking device is a ram device.

5. A vehicle according to any one of the preceding claims and including a swivel joint for permitting the relative swivelling of the first and the second chassis parts.

6. A vehicle according to claim 5 in which the swivel joint is a cylindrical swivel joint disposed about a propeller shaft of the vehicle.

7. A vehicle according to claim 6 in which the swivel joint is located over a front part of the propeller shaft.

8. A vehicle according to any one of claims 5 - 7 in which the swivel joint comprises roller bearings.

9. A vehicle according to any one of the preceding claims and having an engine located between its front and its rear axle.

10. A vehicle according to any one of the preceding claims and having low pressure tyres and articulated steering, for enabling the vehicle to be driven over grass and field surfaces without damage to the grass and field surfaces.

11. A vehicle according to any one of the preceding claims and including a hydraulic power take-off facility.

12. A vehicle substantially as herein described with reference to the accompanying drawings.