GB2160161A

GB2160161A - Load simulator for testing vehicles

Info

Publication number: GB2160161A
Application number: GB08513826A
Authority: GB
Inventors: Robert William Griffiths
Original assignee: GAINFALCON ENGINEERING Ltd
Current assignee: GAINFALCON ENGINEERING Ltd
Priority date: 1984-06-06
Filing date: 1985-05-31
Publication date: 1985-12-18
Also published as: GB8513826D0

Abstract

A load simulator for applying a simulated load to a vehicle, for example a lorry, comprises a framework carrying a pivotted beam one end of which can be applied to the vehicle to apply a load thereto the other end of which is attached to a piston and cylinder device attached at its other end to the framework whereby by supplying pressure fluid to the device and measuring said pressure the load applied can be determined. The simulator is mounted on wheels. <IMAGE>

Description

SPECIFICATION Improved load simulator The present invention concerns improvements in or relating to load simulators, especially but not exclusively load simulators for applying test loads to heavy commercial vehicles.

To test certain aspects of the performance of heavy commercial vehicles it is often necessary to apply load to the load-carrying platform or container so that, for example, the effect of the load on the suspension may be considered.

In the past this has been achieved either by loading the load platform or load container but in view of the high loads often involved this has proved to be relatively labour-intensive and consequently expensive. Alternatively simulated loads have been applied by attaching chains or hawsers to the rear suspension or load platform and exerting a downward force on the chains or hawsers. This latter method, while avoiding the inconvenience of actually loading the vehicle, is difficult to set up and, if care is not taken, can be dangerous.

It is an object of the present invention to obviate or mitigate these disadvantages.

According to the present invention there is provided a load simulator including a base having fixing means whereby it may be anchored to the ground and a load-applying beam pivotally mounted relative to the base about a point intermediate its ends, a load applicator at or near one end of the beam and means connected between the base and a point at or near the other end of the beam for applying a force thereto.

Preferably the beam is supported on a pillar extending upwardly from the base.

Preferably the base is substantially T-shaped in plan having a forward cross member, a pair of spaced longitudinal members extending from said cross member and accommodating therebetween the base of the said pillar and a rear bogie pivotally mounted to the end of the longitudinal members remote from the cross member. The bogie may be resiliently mounted on the longitudinal members. The bogie may be provided with one wheel while two other wheels are provided, one at each end of the cross member.

Preferably the means for applying a force to said other end of the beam comprises a hydraulic or pneumatic piston and cylinder device connected between the base and said end of the beam.

Preferably bracing struts are provided between the connection point of the hydraulic piston and cylinder device to the base and the pivot point of the beam on the pillar.

Preferably the fixing means on the base comprises a ground-engaging member mounted on the longitudinal members. Complimentary means for co-operating with the ground-engaging member may be provided and are adapted for rigid and permanent fixing in the ground over which the simulator has to operate. Preferably said means comprises an open-topped channel member having at least one inwardly directed flange across its top.

Preferably a hydraulic pump for supplying the piston and cylinder device is mounted on the base.

The pump may be driven by an air motor and connection means may be provided for an air supply to said motor connectable to a source of compressed air remote from the simulator.

Preferably a reversible hydraulic motor is provided to drive the single wheel of the bogie.

Preferably a spool valve is provided for controlling the flow of fluid to the motor, said valve being actuable by a pneumatic pilot valve. A further manually operated valve controls the flow of fluid to the piston and cylinder device.

Load distributing means may be fixed to the free end of the beam.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings, in which Figure 1 shows an elevation of a load simulator, and Figure 2 shows an hydraulic/pneumatic circuit for said distributor.

A load simulator comprises a base 10 having a forward cross member 12 with two spaced apart parallel longitudinal members 14 extending rearwardly therefrom. The base of a vertically upstanding pillar 16 is located between and fixed to the longitudinal members and a pair of bracing struts 18 extend between the base and the top of the pillar.

A connection member 20 is fixed to the rear end of the longitudinal members and carries a downwardly directed king pin 22 by which a front bogie 24 is pivotally mounted to the connecting member.

The pivotal mounting including resilient means (not shown) which enable relative vertical movement between the front bogie 24 and the connecting member 20 but which are sufficiently strong to ensure that when no load is applied to or by the simulator the resilient means are fully extended.

This enables a single wheel 26 carried by the bogie to support the front end of the simulator and as wheels 28 are provided at each end of the cross member 12, in the no load condition, the simulator may be wheeled from one location to another.

A reversible hydraulic motor (not shown in Fig.

1) is carried by the bogie 24 and is operable to drive the single wheel 26 of the bogie so that an operator steering the bogie by the handle 30 fixed thereto can manoeuvre the simulator to any desired position.

A beam 40 is pivotally mounted intermediate its end on the top of the pillar 16. The forward end of the beam overhangs the cross member 12 at the front end of the simulator and is provided with a load applicator pad 42. The rear end of the beam is connected to the base 10 by an hydraulic piston and cylinder device 44.

Fixed to the longitudinal members 14 between the base of the pillar and the cross member is a ground engaging member 46 for anchoring the base to the ground during a load simulation. A ground lock is intended to operate in conjunction with a channel member (not shown) fixed in the ground, the channel member being placed with its opening facing upwards and having flanges extending part-way across the opening so that by inserting a cross piece at the bottom end of the ground engaging member into the channel and turning the ground lock through approximately 90" the forward end of the simulator may be locked in position relative to the ground in which it is operating. A connection point 46 for connecting a compressed air hose to the simulator is provided at the rear end of the beam 40.

Fig. 2 shows that an air line 48 extends from the connection point by way of a filter 50 and lubricant supply 52 to an air driven hydraulic pump 54 supplied from a tank 55. A tapping 56 from the air line is lead to a pilot air valve 58 located on the end of the handle 30 of the bogie 24, the pilot air valve by way of lines 60, 62 operating a spool valve 68. Hydraulic fluid under pressure is supplied from the hydraulic pump 54 to the spool valve which diverts it by way of lines 70, 72 to either side of the piston of the hydraulic ram 44 for pivotting the beam 40.

Hydraulic fluid is also supplied to lines 76, 78 under the control of the spool valve 68 to drive the reversible motor 80 for the bogie wheel 26.

In operation, a lorry under test is driven above the fixed channel member of the ground-engaging means and the operator, with the aid of the motor 80 and the pivotal bogie 24 manoeuvres the simulator such that the free end of the beam carrying the load applicator 42 is positioned above the point in the lorry where load is to be applied. The ground engaging means 46 are then applied to fix the forward end of the applicator and the operator causes the hydraulic ram 44 to extend to lower the applicator pad onto the vehicle by use of a manual valve. This first lowering movement causes the resilient means in the connection between the connecting member 20 and the bogie 24 to compress whereby the underside of the rear end of the longitudinal members 14 come into contact with the ground so that the base 10 is firmly held in position.Further supply of hydraulic fluid to the ram 44 applies load to the lorry, the load being a function of the fluid pressure which can be read from a gauge 82 in the fluid line 72 between the pump 54 and the ram 44.

Various modifications can be made without departing from the scope of the invention, for example the base 10 can have any desired configuration. As shown in Fig. 2 a selector valve may be incorporated in the hydraulic line 72 to give controlled incremental output pressures so that a series of loads of known value can be applied merely by appropriate manipulation of the controls 84 thereof. The means for applying load to the beam need not be a hydraulic ram but could be a pneumatic ram or alternatively a screw threaded jack arrangement operated by an electric, hydraulic or pneumatic motor. The simulator need not provide its own hydraulic pressure but could be linked by suitable supply lines to a remote pressure source.

Claims

1. A load simulator including a base having fixing means whereby it may be anchored to the ground and a load-applying beam pivotally mounted relative to the base about a point intermediate its ends, a load applicator at or near one end of the beam and means connected between the base and a point at or near the other end of the beam for applying a force thereto.

2. A simulator as claimed in Claim 1, in which the beam is supported on a pillar extending upwardly from the base.

3. A simulator as claimed in Claim 2, in which the base is substantially T-shaped in plan having a forward cross member, a pair of spaced longitudinal members extending from said cross member and accommodating therebetween the base of said pillar and a rear bogie pivotally mounted to the end of the longitudinal members remote from the cross member.

4. A simulator as claimed in Claim 3, in which the bogie is resiliently mounted on the longitudinal members.

5. A simulator as claimed in Claim 3 or Claim 4, in which the bogie is provided with one wheel while two other wheels are provided, one at each end of the cross member.

6. A simulator as claimed in any one of the preceding Claims, in which the means for applying a force to said other end of the beam comprises a hydraulic or pneumatic piston and cylinder device connected between the base and said end of the beam.

7. A simulator as claimed in Claim 6, in which bracing struts are provided between the connection point of the hydraulic piston and cylinder device to the base and the pivot point of the beam on the pillar.

8. A simulator as claimed in any one of the preceding Claims, in which the fixing means on the base comprises a ground-engaging member mounted on the longitudinal members.

9. A simulator as claimed in Claim 8, in which complimentary means for co-operating with the ground- engaging member are provided and are adapted for rigid and permanent fixing in the ground over which the simulator has to operate.

10. A simulator as claimed in Claim 9, in which said means comprises an open-topped channel member having at least one inwardly directed flange across its top.

11. A simulator as claimed in any one of Claims 6 to 10, in which a hydraulic pump for supplying the piston and cylinder device is mounted on the base.

12. A simulator as claimed in Claim 11, in which the pump is driven by an air motor.

13. A simulator as claimed in Claim 12, in which connection means are provided for an air supply to said motor connectable to a source of compressed air remote from the simulator.

14. A simulator as claimed in any one of Claims 3 to 13, in which a reversible hydraulic motor is provided to drive the single wheel of the bogie.

15. A simulator as claimed in Claim 14, in which a spool valve is provided for controlling the flow of fluid to the motor, said valve being actuable by a pneumatic pilot valve.

16. A simulator as claimed in Claim 15, in which a further manually operated valve controls the flow of fluid to the piston and cylinder device.

17. A simulator as claimed in any one of the preceding Claims, in which load distributing means are fixed to the free end of the beam.

18. A simulator as claimed in Claim 16, in which a selector valve giving a range of controlled output pressures in the supply to the piston and cylinder device is provided to apply preset loadings.

19. A load simulator substantially as hereinbefore described with reference to the accompanying drawings.

20. Any novel subject matter or combination including novel subject matter herein disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.