GB2174649A

GB2174649A - Chassis tilt control for tipper vehicles

Info

Publication number: GB2174649A
Application number: GB08511598A
Authority: GB
Inventors: Roger Victor Prior
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-05-08
Filing date: 1985-05-08
Publication date: 1986-11-12
Also published as: GB8511598D0; GB2174649B

Abstract

In order to stabilise a tipper lorry when raising a heavy load on uneven ground, double acting hydraulic rams (38a, 38b) are mounted on opposite lateral sides of the chassis above the rear axle (28). The rams can be selectively raised and lowered to level the chassis, by bracing it against the axle or the springs by which the axle and road wheels are mounted to the chassis, so that the vehicle's load can be discharged safely. The rams are retracted for normal driving. A control valve (50) supplies hydraulic fluid to the rams from the pump used to actuate the tipping mast, and separate control levers (56a, 56b) independently control each ram to selectively extend, lock and retract it. <IMAGE>

Description

SPECIFICATION Chassis tilt control for tipper vehicles This invention relates to a chassis tilt control for tipper vehicles.

Tipper vehicles are used to convey bulk materials and unload them by tipping a tipper body which is pivotally mounted on the chassis of the vehicle. To do this, one end of the tipper body is raised, normally by means of a hydraulic lifting mast.

Such vehicles are often used to deliver building materials such as sand and gravel to sites where the ground is apt to be uneven. If the tipper vehicle is not on level ground, it will have a tilt; and elevating the tipper body to discharge the load will raise the centre of gravity of the vehicle, with the result that the tilt will tend to increase. This is potentially dangerous, and in extreme cases the vehicle can topple sideways.

It is possible to fit lateral outriggers to the vehicle before tipping is begun in order to brace the vehicle against the ground alongside, but such ground stabilisers are heavy and expensive and are time-consuming to fit to the vehicle. While they are being used, the vehicle cannot be moved, which is a further disadvantage when tipping materials that need to be shaken loose or spread when being tipped, such as tarmacadam, for example.

It is an object of the present invention to overcome or mitigate some or all of these problems.

According to the present invention there is provided a tioper vehicle having a chassis, a tipper body mounted on the chassis, sprung road wheels mounted to the chassis by suspension means, and tilt control means for limiting the tilt of the chassis relative to the road wheels, the tilt control means comprising bracing means operatively mounted between the chassis and the suspension for a road wheel and operable to limit movement of the chassis relative to the said road wheel.

Preferably the bracing means comprises at least one ram or jack operable to raise or lower the chassis relative to the said road wheel. The ram or jack may be provided on each opposite lateral side of the chassis, each such ram or jack being operable to raise or lower the chassis relative to a road wheel on the same side of the chassis as the ram or jack is located.

The said road wheel or wheels are most suitably at least those road wheels that are situated closest to the pivot axis of the tipper body.

The at least one ram or jack is suitably fixedly mounted on the chassis of the vehicle and may comprise an extendable member releasably engageable with the road wheel suspension means. Preferably the extendable member is engageable with reception means mounted on the suspension means.

According to a further aspect of the invention there is provided a tilt control device for use with a tipper vehicle, comprising first and second rams or jacks, attachment means for mounting said rams or jacks on opposite lateral sides of the vehicle chassis each adjacent suspension means for a road wheel of the vehicle, first and second reception means for mounting on said suspension means and for releasably engaging said first and second rams or jacks respectively, means for connecting the rams or jacks to a power source on the vehicle whereby the rams or jacks can be actuated, and control means for selectively actuating the rams or jacks.

The rams or jacks provided in accordance with the invention are most preferably hydraulic rams and each is suitably in the form of a hydraulic piston and cylinder assembly. A tipper vehicle will normally be provided with a hydraulic pump for actuating the tipper mast, and this may conveniently used as the hydraulic power source, connected to the rams by conventional hydraulic circuits including control valves that can be operated from the driver's cab or other convenient location on the vehicle.

One embodiment of the invention is illustrated, by way of example, in the accompanying drawings, in which: Figure 1 is a side elevation of a tipper lorry; Figure 2 is an enlarged view of the hydraulic tilt control ram shown in Figure 1; Figure 3 is a diagram of the hydraulic control circuits for the tilt control rams; and Figure 4 is a rear elevation of the lorry on sloping ground with the chassis and tipper body levelled.

Figure 1 shows a tipper lorry having a chassis 11, a tipper body 12 pivotally mounted at 14 at the rear of the chassis, a hydraulic lifting mast 16 for the tipper body, a driver's cab 18, a pair of front road wheels 20, and tandem rear axles carrying a forward set of rear road wheels 22 and a rearward set of rear road wheels 24 shown in dashed outline to reveal details of the suspension.

The road wheels are mounted to the chassis on conventional suspension means comprising an axle and semi-elliptical leaf spring assemblies. Figure 1 shows most clearly the leaf spring assembly 26 for the rearward rear axle 28, which is clamped to the spring assembly by U-bolts 30 and a clamping plate 32.

As thus far described, the illustrated tipper lorry is entirely conventional.

In accordance with the invention, tilt control means 34 are provided for limiting the tilt of the chassis relative to the road wheels. In the illustrated embodiment, and as most clearly seen in Figure 2, the bracing means of the tilt control means comprise two hydraulic rams 36. Attachment means for the rams 36 com prise ram mounting plates 42, one being bolted on each side of the chassis above the respective rearmost leaf spring assembly 26.

Each hydraulic ram 36 comprises a doubleacting piston and cylinder assembly. Cylinder 38 houses a piston from which a robust ballended piston rod 40 extends downwardly out of the cylinder towards the spring assembly 26. Reception means in the form of a plate 44 provided with a cup for releasably receiving and locating the ball end of the piston rod is mounted on the uppermost leaf of each leaf spring assembly 26. The cylinder 38 is connected to a hydraulic power source by means of a hydraulic fluid feed line 46 for raising the piston rod 40 and a hydraulic fluid feed line 48 for lowering the piston rod 40.

Further details of the hydraulic control circuits are shown in Figure 3, in which the suffix letters a and b identify components of the left hand side and right hand side tilt control means respectively. Hydraulic cylinder 38a is mounted on the left hand side of the chassis and hydraulic cylinder 38b is mounted on the right hand side of the chassis, each being located adjacent the rearmost axle 28. Hydraulic fluid supply lines 46a and 46b connect a valve block 50 to the cylinders 38a and 38b respectively through cylinder ports at. the tops of the cylinders above the pistons therein. Hydraulic fluid supply lines 48a and 48b connect valve block 50 to the cylinders 38a and 38b respectively through cylinder ports at the bottoms of the cylinders below the pistons therein.The lorry is already provided with a hydraulic fluid reservoir and hydraulic pump driven from the engine for actuating the tipping mast, and two additional hydraulic lines are provided to supply and return fluid to and from the tilt control means. These additional lines are line 52 from the hydraulic pump to the valve block 50 and line 54 from the valve block 50 to the reservoir.

The valve block 50 is suitably located in the cab 18 and includes a control lever 56a for a first valve for controlling the fluid supply to the left hand cylinder 38a and a control lever 56b for a second valve for controlling the fluid supply to the right hand cylinder 38b.

Each control lever 56 has three control positions. In the first position, hydraulic fluid under pressure from line 52 is admitted to the line 48 and the line 46 is open to return line 54, so that the piston is moved downwardly in the cylinder 38 to raise the chassis relative to the corresponding road wheel. The second position is a 'hold' position, in which lines 46 and 48 are both closed at the valve block, so that the piston is locked in position in the cylinder 38. In the third position, hydraulic fluid under pressure from line 52 is admitted to the line 46 and the line 48 is open to the return line 54, so that the piston is retracted upwardly into cylinder 8 and the chassis can settle as far as the suspension allows.

Figure 4 shows the tilt control means in use. The tipper lorry is at rest on sloping ground 58. The hydraulic ram 36 on the downhill side of the lorry is extended and the hydraulic ram 36 on the uphill side is retracted to level the chassis 11. The control levers 56 are then moved into their 'hold' positions. The tipper body 12 can now be elevated to unload the vehicle in comparative safety while the chassis is braced against lateral tilting. The lorry can be driven forward if necessary to assist unloading with no need to release the tilt control means.

When unloading is completed and the tipper body 12 has been lowered, the rams 36 are both raised to free the suspension. While it is preferred to use double-acting piston and cylinder assemblies so as to be able to positively raise the rams, single-acting assemblies may be used and provided with piston return springs.

While the illustrated embodiment of the invention shows the use of tilt control means only in respect of the road wheels 24 on the rearmost axle 28, further control. can be achieved by using tilt control means according to the invention on other road wheels. Additional tilt control means on the front road wheels may be used to reduce twisting in the vehicle chassis. It is desirable to provide each hydraulic tilt control means with a separate hydraulic circuit, so that each can be independently and selectively controlled.

In the illustrated embodiment the design of the lorry makes it convenient for the rams to act against the springs of the vehicle suspension, but in other designs of vehicle the rams may act against unsprung components such as axle housings, which are desirably provided with suitable reception means for receiving the rams.

In general it is prefered that rams or jacks comprising the tilt control means be at least operable to raise the chassis relative to a road wheel on one side of the chassis, but in some vehicle designs a satisfactory tilt control may be achievable by lowering the chassis towards a road wheel on the opposite side of the chassis instead.

The use of the tilt control means is not necessarily restricted to tipping on uneven ground. On level ground it may also be advantageous to stabilise the vehicle suspension with the tilt control means while tipping is carried out.

Claims

1. A tipper vehicle having a chassis, a tipper body mounted on the chassis, sprung road wheels mounted to the chassis by suspension means, and tilt control means for limiting the tilt of the chassis relative to the road wheels, the tilt control means comprising at least one double acting ram or jack operatively mounted between the chassis and the suspen sion for a road wheel, the said ram or jack being selectively extendable to brace the chassis relative to the said road wheel and retractable to restore normal springing between the chassis and the said road wheel.

2. A tipper vehicle according to claim 1, wherein a said double acting ram or jack is provided on each opposite lateral side of the chassis, each such ram or jack being operable to brace the chassis relative to a road wheel on the same side of the chassis as the ram or jack is located.

3. A tipper vehicle according to claim 1 or claim 2, wherein the said road wheel or wheels is or are at least the road wheel or those road wheels that are situated closest to the pivot axis of the tipper body.

4. A tipper vehicle according to any one of claims 1 to 3, wherein the at least one double acting ram or jack is fixedly mounted on the chassis of the vehicle and comprises an extendable member releasably engageable with the road wheel suspension means.

5. A tipper vehicle according to any one of claims 1 to 4, wherein each said double acting ram or jack comprises a hydraulic piston and cylinder assembly.

6. A tipper vehicle according to claim 4 wherein the extendable member is releasably engageable with reception means mounted on the suspension means.

7. A tipper vehicle according to claim 6 wherein each said double acting ram or jack comprises a piston and cylinder assembly wherein the cylinder is mounted on the chassis and houses a piston from which a robust bailended piston rod extends out of the cylinder towards a cup for releasably receiving and locating the ball end of the piston rod mounted on the road wheel suspension means.

8. A tipper vehicle according to claim 5 or claim 7, wherein the tilt control means further comprises a hydraulic circuit including a pump, a reservoir, a control valve having an inlet for receiving fluid under pressure from the pump and an outlet for returning surplus fluid to the reservoir, a first hydraulic line connecting the valve to a first cylinder port in a said piston and cylinder assembly for supplying fluid to the cylinder to extend the piston and for returning fluid to the valve upon retraction of the piston, a second hydraulic line connecting the valve to a second cylinder port in said piston and cylinder assembly for supplying fluid to the cylinder to retract the piston and for returning fluid to the valve upon extension of the piston, and a valve control for selecting extension of the piston, retraction of the piston or closure of both of said first and second hydraulic lines to lock the piston position in the cylinder.

9. A tipper vehicle according to claim 8 comprising a plurality of piston and cylinder assemblies each having separate said first and second hydraulic lines to the control valve and a separate valve control whereby each said assembly can be independently and selectively controlled.

10. A tipper vehicle according to any one of claims 5,7,8 and 9 having a tipper mast and a hydraulic pump for actuating the mast, wherein the mast actuating pump serves as the hydraulic pump for each said hydraulic piston and cylinder assembly.

11. A tilt control device for use with a tipper vehicle, comprising first and second double acting rams or jacks, attachment means for mounting said rams or jacks on opposite lateral sides of the vehicle chassis each adjacent suspension means for a road wheel of the vehicle, first and second reception means for mounting on said suspension means and for releasably engaging said first and second rams or jacks respectively, means for connecting the rams or jacks to a power source on the vehicle whereby the rams or jacks can be extended or retracted, and control means for selectively extending and retracting the rams or jacks.

12. A tilt control device according to claim 11, wherein said double acting rams or jacks are hydraulic piston and cylinder assemblies.

13. A tilt control device according to claim 12, wherein each hydraulic piston and cylinder assembly comprises a robust ball-ended piston rod, said attachment means are adapted to mount the cylinders of the said assemblies on the vehicle chassis, and said reception means comprise cups for releasably receiving and locating the ball ends of the piston rods.

14. A tilt control device according to claim 12 or claim 13 wherein the control means comprises a hydraulic circuit including a pump, a reservoir, a control valve having an inlet for receiving fluid under pressure from the pump and an outlet for returning surplus fluid to the reservoir, a first hydraulic line connecting the valve to a first cylinder port in a said piston and cylinder assembly for supplying fluid to the cylinder to extend the piston and for returning fluid to the valve upon retraction of the piston, a second hydraulic line connecting the valve to a second cyilnder port in said piston and cylinder assembly for supplying fluid to the cylinder to retract the piston and for returning fluid to the valve upon extension of the piston, and a valve control for selecting extension of the piston, retraction of the piston or closure of both of said first and second hydraulic lines to lock the piston position in the cylinder, each piston and cylinder assembly having separate said first and second hydraulic lines to the control valve and a separate valve control whereby each said assembly can be independently and selectively controlled.

15. A tipper vehicle substantially as herein described with reference to and as illustrated in the accompanying drawings.

16. A tilt control device for use with a tipper vehicle, substantiaily as herein described with reference to and as iliustrated in the accompanying drawings.