Power assisted steering for motorized pallet truck

• US 20060231302A1
• Filed: 04/19/2005
• Published: 10/19/2006
• Est. Priority Date: 04/19/2005
• Status: Active Grant

• Current Assignee: Hyster-Yale Materials Handling Incorporated (Nacco Industries Incorporated)
• Original Assignee: NMHG Oregon, LLC
• Inventors: Rose, Timothy L.
• Granted Patent: US 7,661,493 B2
• Time in Patent Office: Days
• US Class Current: 180/19.300
• CPC Class Codes: B62B 3/0612 power operated
• CPC Class Codes: B62D 1/14 Tillers, i.e. hand levers operating on steering columns
• CPC Class Codes: B62D 5/00 Power-assisted or power-driven steering for non-deflectable wheels B62D11/00; fluid-pressure servomotors in general F15B
• CPC Class Codes: B62D 51/001 characterised by the vehicle control device mechanical features of control devices in general G05G; arrangements of vehicle control devices in general B60K20/00, B60K23/00, B60K26/00
• CPC Class Codes: B62D 51/04 the driver walking
• CPC Class Codes: B62D 6/00 Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00
• CPC Class Codes: B66F 9/20 Means for actuating or controlling masts, platforms, or forks power take-off from vehicle transmissions, combined with vehicle propulsion systems B60K

Abstract

A system for controlling the acceleration, deceleration, braking, travel speed, and power assisted steering of a pallet truck, comprising setting a steering system and a traction system performance as a function of a position and rate of change of position of a control arm in a vertical axis and a horizontal axis of rotation.

Claims

1. A method for controlling the acceleration, deceleration, braking, and travel speed of a motorized vehicle, comprising:

setting a level of performance of a traction system as a function of an operator command and position of a steering control.

2. The method according to claim 1 including the operator command providing an angle of the steering control in a vertical axis and a horizontal axis of rotation.

3. The method according to claim 2 including providing a sensor or sensors which determine the angle of the steering control.

4. The method according to claim 1 including providing an on-board processor which determines a level of performance of the traction system based on the position of the steering control.

5. The method according to claim 4 including using a data map to provide the on-board processor with predetermined values based on the position of the steering control.

6. The method according to claim 4 including using an algorithm or equation to determine the level of performance of the traction system based on the position of the steering control.

7. The method according to claim 2 including having predefined discrete ranges of motion in the vertical and horizontal axes of rotation.

8. The method according to claim 7 including three or more predefined discrete ranges of motion in each of the vertical and horizontal axes of rotation.

9. The method according to claim 7 including determining traction system performance based on where the steering control is located within the predefined discrete ranges of motion.

10. The method according to claim 1 wherein the traction system performance varies depending if the motorized vehicle is traveling in a low speed mode or a high speed mode.

11. The method according to claim 1 wherein the operator command determines a rate of change of position of a steering control, and setting the traction system performance as a function of the rate of change of position of the steering control.

12. The method according to claim 11 including providing a sensor that determines the rate of change of position of the steering control in a vertical direction, and a sensor that determines the rate of change of position of the steering control in a horizontal direction.

13. The method according to claim 11 including providing an on-board processor which uses an algorithm or equation to calculate the allowable setting for the traction system performance based on the position of the steering control and the rate of change of position of the steering control.

14. The method according to claim 11 including using a data map which provides an on-board processor with predetermined settings for the traction system performance based on discrete positions of the steering control and the rate of change of position of the steering control.

15. The method according to claim 11 including setting the traction system performance as a function of the rate of travel of the pallet truck.

16. A method for controlling the permissible torque assistance provided by a power assist steering system, comprising:

setting a level of performance of the power assist steering system as a function of an operator command and position of a steering control.

17. The method according to claim 16 including the operator command providing an angle of a steering control in a vertical axis and a horizontal axis of rotation.

18. The method according to claim 17 including providing a sensor or sensors which determine the angle of the steering control.

19. The method according to claim 16 including providing an on-board processor which determines a level of performance of the power assist steering system based on the position of the steering control.

20. The method according to claim 19 including using a data map to provide the on-board processor with predetermined values based on the position of the steering control.

21. The method according to claim 19 including using an algorithm or equation to determine the level of performance of the power assist steering system based on the position of the steering control.

22. The method according to claim 17 including having predefined discrete ranges of motion in the vertical and horizontal axes of rotation.

23. The method according to claim 22 including three or more predefined discrete ranges of motion in each of the vertical and horizontal axes of rotation.

24. The method according to claim 22 including determining power assist steering system performance based on where the steering control is located within the predefined discrete ranges of motion.

25. The method according to claim 17 wherein the power assist steering system performance varies depending if the motorized vehicle is traveling in a low speed mode or a high speed mode.

26. The method according to claim 16 wherein the power assist steering system provides torque assistance if the operator command indicates an operator provided steering torque greater than a threshold torque value.

27. A system for controlling a pallet truck, comprising:

a traction motor for driving the pallet truck;

a control arm for steering a drive wheel that controls a direction of travel of the pallet truck;

a steer motor for providing torque for steering the drive wheel; and

a processor controlling the traction motor and the steer motor according to a monitored movement and position of the control arm in conjunction with a monitored amount of torque applied to the control arm.

28. The system according to claim 27 wherein the processor controls the traction motor and the steer motor according to both a monitored vertical and horizontal movement and position of the control arm.

29. The system according to claim 28 wherein the processor varies the amount of torque applied by the steer motor to assist in steering the steer wheel according to the monitored vertical and horizontal movement and position of the steer arm in conjunction with the amount of torque used by an operator to move the steer arm into the different vertical and horizontal positions.

30. A method for controlling a motorized vehicle, comprising:

controlling acceleration, deceleration, braking, and travel speed of the motorized vehicle according to a vertical and horizontal position of a steering controller.