GB2267471A

GB2267471A - Roller vehicle steered by differential drive and/or braking.

Info

Publication number: GB2267471A
Application number: GB9215618A
Authority: GB
Inventors: James William Hargreaves; George Edward Hobbs
Original assignee: Sisis Equipment; Sisis Equipment Macclesfield Ltd
Current assignee: Sisis Equipment; Sisis Equipment Macclesfield Ltd
Priority date: 1992-06-06
Filing date: 1992-07-23
Publication date: 1993-12-08
Also published as: GB9215618D0; GB9212034D0

Abstract

The vehicle, eg a ride-on roller, is mounted on multiple rollers (21, 23) and driven by an engine (11) via a drive transmission system (17). Two separate output axles (18, 19) provide drive to two or more sets of rollers one on each side of a longitudinal centre line of the vehicle. Each drive axle has a brake (24, 25) such that by selectively braking one or other drive axle the vehicle may be steered. The steering may be enhanced by increasing the speed of drive to one drive axle whilst simultaneously braking the other. The vehicle may be used to tow a ground effect roller or other implements and is intended for use in the treatment of turf or non-turf playing areas such as golf courses, bowling greens and playing fields. <IMAGE>

Description

A VEHICLE THIS INVENTION concerns a vehicle mounted on multiple rollers, preferably a small tractor unit to be driven by an operator and having means for towing or propelling ground-effect implements such as rollers, rakes and the like, usually for the treatment of turf on non-turf playing areas, such as on golf courses, bowling greens and playing fields. The invention may be applied also to self-driven ground-effect vehicle units where no separate power unit is required.

An object of the present invention is to provide an improved drive and steering system for such a machine which will provide forward and reverse drive with variable speed control and an improved steering mechanism when compared with similar conventional vehicles steered by turning the front or rear roller pair.

According to the present invention there is provided a vehicle mounted on multiple rollers driven by an engine via a transmission drive system; characterised in that the transmission drive system provides separate drive axles one to each side of a longitudinal centre line of the vehicle; in that the rollers are provided in two or more sets, one to the left and the other to the right of said vehicle centre line, and each set consisting of two or more rollers mounted one behind another; in that each set may be driven from one half drive axle of the drive transmission system; and in that means are provided to enable a speed differential between sets of rollers enabling the vehicle to be steered selectively.

Preferably the rollers are provided in two pairs, mounted respectively on opposite sides of the centre line of the vehicle; and in that said speed differential is effected by means adapted to enable braking of each half drive axle independently of the other thus to reduce the drive to one roller set relative to the other.

If required, in the longitudinal direction of the vehicle, a non-driven central set of rollers may be disposed between two outer driven sets. Furthermore, in the transverse direction a non-driven pair or set of rollers may be provided between driven pairs or sets disposed for and aft of the non-driven pair or set.

In another example, instead of, or in addition to, braking each half drive axle independently of the other, the speed of drive to the other half axle may be increased.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a general side view of a vehicle made in accordance with the invention; and Fig. 2 is a general plan view.

The vehicle consists of a framework generally indicated at 10 on which is mounted a small internal combustion engine 11 or other drive unit. Towards the rear of the vehicle at a position generally indicated at 12, there is provided a driver's seat (not shown) from which the driver facing transversely of the direction of movement of the vehicle can operate the latter for forwards movement in the direction of arrow 13, or in reverse.

A pair pivoted arms 14 provide an attachment for a ground-effect implement such as a roller 15 to be towed along the ground.

A vertically disposed output shaft 16 of engine 11 provides the input motive power to, for example, an hydraulic drive system generally indicated at 17. The system 17 provides a pair of aligned half drive axles 18 and 19 extending from the drive system 17 in two opposed directions, one on each side of a longitudinal centre line of the vehicle. Each drive axle 18, 19 is connected via chain 20 to a rear split roller 21. In turn, the drive is transmitted via a further chain 22 on each side of the vehicle to a further split roller 23. The rollers 21 and 23 are divided about the longitudinal centre line of the vehicle so that the two halves of each roller may rotate independently of one another thus providing two pairs of roller halves one to the left and the other to the right of said centre line.

Preferably, the roller 15 is also split about the same line.

Mounted on the drive axles 18, 19 are a pair of brakes 24 and 25 respectively which are connected by cables 26 and 27 to a common steering column 28 which terminates uppermost at right angles in a horizontal steering handle 29 close to the seating position of the driver.

In operation, in this embodiment, the two pairs of drive roller halves on the two sides of the vehicle are driven independently of one another from the drive system 17. The vehicle may be steered by altering the speed of one pair of rollers in relation to the opposite pair by braking the half drive axles selectively. For example, if the steering handle 29 and column 28 are turned to actuate, via cable 26, brake 24 on axle 18, the two split roller halves to the left-hand side of the vehicle are braked allowing the right-hand pair to continue in drive thus steering the vehicle to the left. In this mode, the hydraulic drive system, if required, may apply increased speed of drive to the right-hand rollers thus providing very rapid steering. Similarly, if the right-hand pair is braked then the vehicle steers to the right.

Preferably, a transmission lock is provided such that both roller pairs may be locked when required for parking. The pair of arms 14 supporting the roller 15 are pivotally mounted on a shaft 30 and carry between them a bar 31 which may be raised and lowered by an operator handle (not shown) of a conventional type, thus to determine the operational height of the roller 15.

In this example, the engine 11 suitably may be a 72- horse power vertical-shaft petrol engine.

As will be seen in Fig. 1, a drive pedal 35 is pivotally mounted about its mid-point and may be depressed at either end thus to operate selectively one or other of a pair of valves 36, 37 adapted to select the direction of drive from the hydraulic system 17. When the pedal is released and assumes a horizontal position no drive is transmitted to the rollers and the vehicle remains stationary. The speed at which the axles 18, 19 are driven by the drive system 17 is determined by the amount by which the pedal 35 is depressed. Thus the pedal serves as an accelerator so that the driver may select the speed of operation.

Preferably, the steering column 28 is biased to assume a central position when released so that all four or more driven rollers drive the vehicle in a straight line.

The hydraulic drive system may be replaced by a mechanical drive axle providing drive separately to the two sides of the vehicle.

Claims

1. A vehicle mounted on multiple rollers driven by an engine via a drive transmission system; characterised in that the drive transmission system provides separate drive axles one to each side of a longitudinal centre line of the vehicle; in that the rollers are provided in at least two sets, one to the left and the other to the right of the vehicle centre line, and each set consisting of at least two rollers mounted one behind another; in that the roller sets may be driven separately by the two drive axles of the drive transmission system; and in that a steering mechanism enables a speed differential between sets of rollers to steer the vehicle.

2. A vehicle according to Claim 1, wherein the rollers are provided in two pairs, mounted respectively on opposite sides of the longitudinal centre line of the vehicle; and wherein the steering mechanism is adapted to brake each drive axle independently of the other thus to reduce the drive to one roller set relative to the other.

3. A vehicle according to Claim 1 or Claim 2, including a non-driven central set of rollers spaced mounted between two outer driven sets.

4. A vehicle according to Claim 2 including at least one non-driven pair of rollers aligned transversely across the vehicle and disposed between front and rear driven pairs.

5. A vehicle according to Claim 1, wherein the steering mechanism is adapted to increase the speed of drive to one drive axle simultaneously with braking of the other drive axle thus to increase the speed differential between the two drive axles.

6. A vehicle according to Claim 1, wherein said drive transmission system is an hydraulic drive system connected via a pair of half drive axles respectively to two sets of said rollers.

7. A vehicle according to Claim 1, wherein a first roller of each set of rollers is drivingly connected by a separate drive transmission means to at least one further roller of the set.

8. A vehicle according to Claim 1, including a pair of brakes mounted one on each of the drive axles, and a common steering column to which the brakes are connected and which may be operated selectively to apply one or other of the brakes.

9. A vehicle according to Claim 8, including means to cause the common steering column to assume a central or neutral position when released such that all driven rollers will transport the vehicle in a straight line.

10. A vehicle according to Claim 1, including a drive pedal pivotally mounted about its mid-point and capable of being pressed selectively at either end, a pair of valves adapted to be actuated by movement of the drive pedal to select the direction of drive from the drive transmission system, the pedal, when released, being adapted to return to a neutral position in which no drive is transmitted to the rollers and the vehicle remains stationary.

11. A vehicle according to Claim 10, wherein said drive pedal provides a variable speed control thus to serve as an accelerator whereby a driver may select a speed of drive.

12. A vehicle according to Claim 1, wherein said drive transmission system comprises a mechanical drive axle providing drive separately to the two sides of the vehicle.