GB2139164A - A motor vehicle with elevatable working platform - Google Patents

Abstract

A motor vehicle designed to be driven at normal road speeds, e.g. in excess of 25 miles per hour by an engine (14), drive transmission device (13) and steering mechanism (15), carries above its chassis (10) an articulated boom structure (16) with a working platform (21) at its remote end. An additional set of controls (26a) on the platform (21) is adapted to control drive of an hydraulic motor (30) connectable to the vehicle wheels (12), and to control drive of an hydraulic motor (34) connected to the steering mechanism (15) so that the vehicle can be manoeuvred at slow speeds e.g. of 5 miles per hour or less, by an operator situated on the platform (21). Controls (26) are also provided on the chassis (10). Means are provided for minimising roll of the chasses (10) when an operator is on the elevated platform. In an alternative embodiment, hydraulic motors drive rollers engageable with the peripheries of a pair of vehicle wheels (12). <IMAGE>

Description

SPECIFICATION A motor vehicle This invention concerns motor vehicles with hydraulically operated access equipment mounted thereon, to enable an operator to gain access to locations high above the ground, such as lamp standards or the upper storeys of a building, or for aircraft cleaning, de-icing, and servicing and wherein the vehicle and the equipment are adapted to be manoeuvred by the operator using a set of controls located in a working plafform at the outermost end of a hydraulically elevatable boom structure. Such vehicles are generally referred to as being selfpropelled, and for operational and safety reasons the travelling speed of the vehicle, when the booms are elevated, is limited to approximately walking speed.

A disadvantage of conventional vehicles of this type is that they do not have the ability to travel at normal road speeds nor do they comply with regulations governing the design and capabilities of vehicles intended for use on public highways.

In some cases, such a vehicle may be required to travel substantial distances between working locations, and it is therefore an object of the present invention to provide a vehicle which has the operating advantages of a self-propelled machine but which is capable of operating as a normal road vehicle for travel between working locations.

According to the present invention, there is provided a motor vehicle having an engine, drive transmission device steering mechanism, and controls to enable the vehicle to be driven conventionally from a driver's cab at normal road speeds, e.g. in excess of 25 miles per hour, said vehicle carrying hydraulically operated access equipment including an operator-occupied working platform mounted at the distal end of an hydraulically elevatable boom structure, said equipment being manoeuvred by an hydraulic drive connected to the vehicle engine, characterised in that an additional set of controls is provided on said working platform and adapted for connection to said steering mechanism and to means for propelling the vehicle such that the vehicle may be manoeuvred by the operator situated on the working platform, at low speeds, e.g. in the region of 5 miles per hour or less.

An embodiment of the invention will be described, by way of example only, with reference to the accompaying drawings, which illustrate a motor vehicle equipped in accordance with the invention, and in which: Figure 1 is a schematic side elevation of the vehicle according to one embodiment; Figure 2 is a rear elevation of a vehicle according to a second embodiment; and Figure 3 is a partial side elevation showing the second embodiment.

Referring now to the drawings, the vehicle comprises a chassis 10 with driver's cab 11. One or more driving wheels 12 are connected via a gearbox 13 to the main vehicle engine 14. The front wheels of.the vehicle are steered by conventional steering wheel and gear as indicated generally at 15, and the vehicle is driven in a conventional manner using controls in the cab 11.

In this example, the vehicle carries a boom structure generally indicated at 16 which comprises a first boom 17 pivotally mounted on a horizontal axis relative to a supporting structure 19 which is rotatable on a turntable 18. Pivotally mounted on a horizontal axis at the remote end of boom 17 is a second boom 20 which carries at its free end a working platform 21. Movements of the articulated boom structure 16 are powered buy a pairofhydraylic rams 22 and 23 in conventional manner, to enable the booms to be manoeuvred from a substantially horizontal folded position to a fully elevated position in which they assume a substantially vertical configuration.

The vehicle engine 14 is connected to a power take-off drive 24 which itself drives an hydraulic pump 25. An additional set of controls 26 (duplicated at 26a on the working platform 21) delivers hydraulic fluid from the pump 25 to the rams 22 and 23, to an hydraulic motor (not shown) connected to the turntable 18, and to an hydraulic motor 30 for a purpose to be described.

The controls 26, 26a are also adapted to deliver fluid from pump 25 to a 3-way valve 32 in order to drive a small hydraulic motor 34 drivingly connected by pinions 35 to the steering column of steering gear 15.

The vehicle is capable of being driven at normal road speeds directly by the engine and associated gearbox 14, and the steering gear 15, all from the driver's cab.

When a working operation using the boom structure 16 is to be carried out with the vehicle stationary or travelling at low speed, clutch 31 is operated by manipulation of a control (not shown) to disconnect the driving wheels 12 and their drive shafts 36 from engine and gearbox 14 and to enable them to be connected directly to the hydraulic motor 30 driven by pump 25 from power take-off 24 by manipulation of the controls 26, 26a. Actuator 37 and 3-way valve 38 determine the direction of drive.

According to the position of valve 32 as determined by actuator 33 the hydraulic motor 34 can be driven to manoeuvre the vehicle to the left or to the right by actuating the steering gear 15. Actuators 37 and 33 are operated by controls 26, 26a which are thus manipulated to cause the vehicle to travel at low speed so that an operator on the platform can manoeuvre the vehicle from one work station to another. Similarly, the booms can be raised and lowered in the conventional manner using one or other of the control sets 26, 26a.

Conveniently, valves 32 and 38 and their associated actuators 33 and 37, and all associated conduits are accommodated on the chassis 10.

Many road vehicles are equipped with a "fail-safe" braking system so that in the event of failure of the vehicle systems the brakes are automatically engaged: Therefore, to use the present vehicle in the self-propelled mode, the brakes must be released, and in order to stay released the vehicle engine must be running to maintain full operation of the pneumatic, hydraulic and electrical operating systems of the vehicle. Thus, the power take-off drive conveniently replaces the auxiliary engine conventionally required to drive the working apparatus.

Since the vehicle brakes would need to be disengaged when using the vehicle in the self-propelled mode, the hydraulic motor 30 must be of the type which incorporates a brake which engages automatically when the motor stops and is released automa ticallywhen it is to rotate.

Conventional interlock systems must be incorporated to ensure than when the vehicle is required for normal road operation, the hydraulic motor 30 is automatically disengaged, and the valves 32 and 38 assume their central positions. Oil in motor 34 must circulate freely without intefering with normal movements of the steering gear.

Conventional self-propelled vehicles usually have axles which are mounted rigidly to the base frame or chasses to prevent the latter from tilting when manoeuvring the boom system to the sides of the vehicle. Thus when using the present vehicle in the self-propelled mode it will be necessary to ensure that the vehicle axles are rigid or substantially rigid with respect to the chassis. This can be achieved by mounting the vehicle axles on rubber rather than on springs, giving an almost rigid connection between the axle and the chassis. Alternatively, heavy duty anti-roll bars can be provided which allow vertical movement between the axles and the chassis but only limited lateral movement. As a further alternative, the axle or axles can be fitted with devices which can be locked relative to the chassis when the vehicle is to be used in the self-propelled mode.

Referring now to Figures 2 and 3, in an alternative arrangement hydraulic motors 50 and 51 are mounted to drive rollers 52 and 53 pivotally mounted via arms 54 and a common shaft 55 to the chassis 10.

One or more hydraulic cylinders 56 are provided to pivot arms 54 and shaft 55 so to bring rollers 52 and 53 into or out of frictional engagement with an adjacent pair of vehicle wheels 12.

This arrangement avoids the need for connection of the hydraulic drive motor to the drive shafts 36 of the vehicle and enables the vehicle to be driven at slow speeds in either direction by appropriately selecting the direction of rotation of the motors 50 and 51. When the vehicle is to be driven at normal road speeds, the rollers 52 and 53 are withdrawn to the positions indicated in dotted lines in Figure 3.

When the rollers 52 and 53 are in contact with the wheels, the pivotted arms 54 act so as to lock the axle relative to the chassis 10 to prevent tilting thereof during operation of the boom system. With this arrangement, therefore, the vehicle suspension can be of conventional springs or hydraulictype, thus avoiding the need for a special suspension system suitable for both modes of operation.

It is not intended to limit the invention to the above examples only, many variations, such as might readily occur to one skilled in the art, being possible without departing from the scope of the invention.

For example, the hydraulic motor 34 can be replaced by a double-acting cylinder providing linear movemenu to the steering gear. Furthermore, some or all of the hydraulic systems can be replaced by electrical or pneumatic systems driven from the power take-off drive 24.

Furthermore the hydraulic motor 30 and clutch 31 can be omitted by providing controls on the working platform to operate the normal automatic transmission system and accelerator of the vehicle to drive the vehicle in the requisite slow speed range.

Claims (10)

1. A motor vehicle having an engine, drive transmission device and steering mechanism, and controls to enable the vehicle to be driven conven tionallyfrom a driver's cab at normal road speeds, e.g. in excess of 25 miles per hour, said vehicle carrying hydraulically operated access equipment including an operator-occupied working platform mounted on an hydraulically elevatable boom structure, said equipment being manoeuvred by an hydraulic drive connected to the vehicle engine, characterised in that an additional set of controls is provided on said working platform and adapted for connection to said steering mechanism and to means for propelling the vehicle such that the vehicle may be manoeuvred by the operator situated on the working platform, at low speeds, e.g. in the region of 5 miles per hour or less.

2. A motor vehicle according to Claim 1, wherein said means for propelling the vehicle comprises at least one hydraulic motor drive-connected to the vehicle engine by a power take-off device.

3. A motor vehicle according to Claim 1, or Claim 2, wherein said at least one hydraulic motor is adapted for connection by way of a clutch to a driveshaft connecting the vehicle engine to at least one of its wheels.

4. A motor vehicle according to Claim 1 or Claim 2, wherein said at least one hydraulic motor is connected to means adapted for frictional driving engagement with a vehicle wheel.

5. A motor vehicle according to Claim 4, wherein said at least one hydraulic motor is drive-connected to said wheel via a roller frictionally engaged with the vehicle wheel, and wherein upon engagement, the roller and a pivotted arm upon which it is mounted serve as an axle lock to prevent relative movement between the axle of said wheel and the vehicle chassis.

6. A motor vehicle according to Claim 1, wherein said additional set of controls is adapted to operate a valve determining the passage and direction of flow of hydraulic fluid to means producing movement of said steering mechanism.

7. A motor vehicle according to Claim 1, wherein said additional set of controls includes means selec tire to determine the passage and direction of flow of hydraulic fluid to an hydraulic motor connected to drive at least one of the vehicle wheels.

8. A motor vehicle according to Claim 1,wherein a duplicate set of said additional set of controls is located on or adjacent the vehicle chassis.

9. A motor vehicle according to Claim 1, wherein said means for propelling the vehicle comprises the vehicle engine, and said additional set of controls is adapted to operate the drive transmission device and the accelerator of said engine to drive the vehicle within a requisite slow speed range.

10. A motor vehicle, substantially as hereinbefore described with reference to and as illustrated in Figure 1 or Figures 2 and 3 of the accompanying drawings.