GB2025004A - Manual Command System for Vehicle Transmission - Google Patents

Abstract

A vehicle control mechanism has a speed and direction selection lever 15 movable manually and infinitely adjustable between full speed forward, zero and full speed reverse positions, and a speed control device comprising a lever 21 Fig. 3 movable about a pivot D by a handle 13 which is spring-biased toward a zero position. A connector 20, movable longitudinally of the lever by the control lever 15, is coupled to a speed and direction control rod 17 associated with the drive means 18 of the vehicle and extending perpendicular to lever 21 in the zero position of handle 13. Thus, the direction and extent of pivotal movement of the lever 21 about the pivot D from its zero position, as controlled by handle 13 and by the extent and direction of displacement of the connector 20 along the lever 21 from the axis of said pivot D is controlled by the selection lever 15 (See Fig. 1). <IMAGE>

Description

SPECIFICATION Improvements in and Relating to Control Mechanisms for Vehicles This invention relates to a control mechanism for a vehicle, in particular a control mechanism incorporating a speed control device, e.g. a deadman's handle.

A deadman's handle is a handle by means of which a vehicle can be maintained in motion by pressure of the driver's hand on the handle, the hand being biassed toward a zero or stop position so that if the driver releases his pressure on the handle, the handle is biassed back to zero position to bring the vehicle to a halt.

According to the present invention, there is provided a speed and direction control mechanism for a drive system of a vehicle, said mechanism comprising an actuator manually operative to set the direction of drive and the maximum speed in that direction, and a speed control device manually movable over a fixed distance to infinitely adjust the instantaneous speed in the direction set by the actuator over a speed range, the maximum of which is set by the actuator.

The present invention also provides a vehicle control mechanism comprising a speed and direction control member whose extent and direction of longitudinal displacement from a neutral position respectively determine the maximum speed and direction of movement of the vehicle, and a manually operable actuator connected to said member and operable to displace said member, said member being movable laterally by movement of said actuator and further comprising a lever connected to a manually operable speed-control device which is spring-biassed about its pivot axis toward a zero position, said speed-control device carrying a connector which is slidably movable by said actuator along said lever to opposite sides of its pivot axis, said speed and direction control member being secured to said connector.

The present invention further provides a vehicle control mechanism which comprises a speed and direction control actuator movable by manual operation between full speed forward, zero and full speed reverse positions and locatable at intermediate positions therebetween, a speed control device comprising a lever movable about a pivot by a handle which is spring-biassed toward a zero position and a connector movable longitudinally of the lever by the direction control actuator, the connector being coupled to a speed and direction control member associated with the drive means-of the vehicle, so that the direction and extent of movement of the said control member is determined by the extent of pivotal movement of the said lever about said pivot from its zero position, and by the extent and direction of displacement of the connector along the lever from the axis of said pivot.

Preferably the range of possible movement of the lever and of the direction control member are such that the speed of the vehicle can be determined by either the extent of movement of the safety handle orthe extent of movement of the direction control member from a neutral position.

The invention will now be described in detail by way of example with reference to the accompanying drawings in which: Figure 1 is a verticle section, part in elevation, through part of a double drum vibrating roller together with its control mechanism Figure 2 is a plan view of part of the mechanism of Figure 1 seen in the direction of the arrow Z in Figure 1; Figure 3 is a section on the line Ill-Ill of Figure 1,and Figure 4 is a section onthe line lV-lV of Figure 1.

The pedestrian-controlled double drum vibrating roller shown in Figure 1 is of a type in which one or each drum of the roller is driven from an i/c engine via a hydrostatic transmission, including a variable displacement hydraulic pump, to provide infinitely variable control over the travel speed of the roller. No details of the roller are shown but the direction and speed of the vehicle are controlled by the control mechanism, indicated by the general reference 10 which is mounted on a steering arm 11 extending as a cantilever from the roller frame 12.The control mechanism comprises a deadman's our safety handle 13 mounted within a hand support 14 rigidly mounted on the steering arm 11, a speed/direction selection lever 15, all these parts being located at the outer end of the control arm, and a pump lever 1 6 located at the opposite end of the arm 11, and connected to the deadman's handle and to the speed/direction selection lever by a control rod 1 7. The pump lever 16, which is pivotally mounted on the housing of the variable displacement hydraulic pump 1 8, is movable arcuately from a full speed forward position via zero to a full speed reverse position.

The end of the control rod 1 7 adjacent the roller frame 12 is pivotally connected to the outer end of the pump lever 1 6 so that it extends substantially normal to the pump lever when the lever 1 6 is in its zero position.

The opposite end of the control rod carries a connector 20 in the form of alsiiding pivot which is slidable along a centrally pivoted lever member 21. The lever member 21 is movable about its pivot D by the deadman's handle 13 which is biassed towards its stop position by a spring 23.

As shown in Fig. 3, the lever member 21 is carried by a yoke 21 a which is pivoted at D in the steering arm 11 and rigidly connected to the handle 13. In the stop position of the deadman's handle 13, the lever member 21 is perpendicular to the length of the control rod 17 so that the rod can be moved laterally to locate the sliding pivot 20 at any selected position along the lever member 21.

This sliding movement of the sliding pivot 20 is effected by movement of the speed/direction selection lever 1 5 which is a bell crank lever pivotally supported for movement in the same plane as the plane of movement of the deadman's handle 13. The pivot axis E of the ball crank lever passes through the zero position of the control rod, i.e the position in which the sliding pivot 20 coincides with the pivot axis of the lever member 21. One arm 1 5a of the bell crank lever forms the handle of the selection lever whereas the other arm 1 sub is pivoted through a sliding pivot member 22 to the control rod 17.Thus pivotal movement of the speed/direction selection lever 15 is effective to move the sliding pivot member 22 and hence the control rod 1 7 over an arc of movement corresponding to the extreme positions of the sliding pivot 20 of the lever member to which the deadman's handle is connected.

It will be understood that when the deadman's handle is moved from its stop position fully toward its drive position, indicated in a chain line in Figure 1. the lever member 21 is moved over its full arc of movement and accordingly the control rod 17 is moved in a forward or reverse direction depending on which side of the pivot the sliding pivot member is located, the extent of longitudinal movement of the control rod being dependent on the distance of the sliding pivot member 20 from the pivot axis D of the lever member 21.

Accordingly, if the deadman's handle is to be maintained in the drive position up against the hand support, the direction of movement and the speed of movement of the roller will be determined wholly by the position in which the speed/direction selection lever 1 5 is set. This setting can be maintained by a friction member (not shown) acting at the pivot E of the bell crank lever member 21 or alternatively a plurality of discrete positions or the lever member 21 can be determined by a sprung detent carried for example by the bell crank lever which is engageable in any selected one of a plurality of recesses on a cooperating member mounted on the steering arm, as shown in Fig. 4.

Alternatively, the speed/direction selection lever 1 5 can be located in one or other of its extreme forward or extreme reverse positions and the speed can be selected by varying the distance which the deadman's handle is moved away from its stop position. In other words, the speed/direction selection lever can be set to full speed in the selected direction, and the chosen speed determined by movement over the deadman's handle, or alternatively the speed/direction selection lever can be moved to a selected speed in the selected direction and the deadman's handle moved fully from its stop to its full speed drive position.

In either case, by squeezing or releasing the deadman's handle, a slow smooth starting and stopping of the vehicle is achieved, which is desirable in pedestrian operated machinery, but in an emergency release of the deadman's handle will stop the machine quickly.

Moreover, by setting the speed/direction selection lever at a low speed, a very fine control of speed can be achieved by movement of the deadman's handle.

Although the invention has been described in relation to a pedestrian-controlled doubledrum roller, it is also applicable to pedestrian-controlled single drum rollers and driver-mounted vehicles.

Claims (7)

Claims

1. A speed and direction control mechanism for a drive system of a vehicle, said mechanism comprising an actuator manually operative to set the direction of drive and the maximum speed in that direction, and a speed control device manually movable over a fixed distance to infinitely adjust the instantaneous speed in the direction set by the actuator.

2. A vehicle control mechanism comprising a speed and direction control member whose extent and direction of longitudinal displacement from a neutral position respectively determine the maximum speed and direction of movement of the vehicle, and a manually-operable actuator connected to said member and operable to displace said member, said member being movable laterally by movement of said actuator and further comprising a lever connected to a manually operable speed-control device which is spring-biassed about its pivot axis toward a zero position, said speed-control device carrying a connector which is slidably movable by said actuator along said lever to opposite sides of its pivot axis, said speed and direction control member being secured to said connector.

3. A vehicle control mechanism which comprises a speed and direction control actuator movable by manual operation between full speed forward, zero and full speed reverse positions and locatable at intermediate positions therebetween, a speed control device comprising a lever movable about a pivot by a handle which is spring-biassed toward a zero position and a connector movable longitudinally of the lever by the direction control actuator, the connector being coupled to a speed and direction control member associated with the drive means of the vehicle, so that the direction and extent of movement of the said control member is determined by the extent of pivotal movement of the said lever about said pivot from its zero position, and by the extent and direction of displacement of the connector along the lever from the axis of said pivot.

4. A control mechanism according to Claim 3 wherein the control member is a control rod which is perpendicular or substantially perpendicular to the lever when the lever is in its zero position.

5. A control mechanism according to claim 4 wherein said actuator comprises a bell crank lever, one arm of which forms a hand grip, the other arm of which is pivoted adjacent its outer end to the control rod.

6. A control mechanism according to any preceding claim wherein the range of possible movement of the connector and of the actuator are such that the speed of the vehicle can be determined by either the extent of movement of the speed-control device or the extent of movement of the actuator in selected direction from a neutral position.

7. A control mechanism substantially as herein described with reference to the accompanying drawing.