Dynamic vibration control systems and methods for industrial lift trucks

• US 9,403,667 B2
• Filed: 12/06/2011
• Issued: 08/02/2016
• Est. Priority Date: 03/18/2011
• Status: Active Grant

• Current Assignee: The Raymond Corporation (Toyota Motor Corporation)
• Original Assignee: The Raymond Corporation (Toyota Motor Corporation)
• Inventors: McCabe, Paul P., Kirk, John B., Gregory, Bryce, Field, Michael G.
• Primary Examiner(s): Wilson, Lee D
• Application Number:
  US13/312,722
• Publication Number:
  US 20120235100A1
• Time in Patent Office: 1,701 Days
• US Class Current: 1/1
• CPC Class Codes: B60G 17/08 Characteristics of fluid dampers adjusting fluid dampers in general F16F9/44 - F16F9/53
• CPC Class Codes: B60G 2300/022 Fork lift trucks, Clark
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2800/91 Suspension Control
• CPC Class Codes: B62B 2301/00 Wheel arrangements; Steering; Stability; Wheel suspension
• CPC Class Codes: B62B 3/0612 power operated
• CPC Class Codes: B62B 5/0006 Bumpers; Safety devices
• CPC Class Codes: B62B 5/0069 Control
• CPC Class Codes: B66F 17/003 for fork-lift trucks
• CPC Class Codes: B66F 9/07559 Stabilizing means
• CPC Class Codes: B66F 9/07586 Suspension or mounting of wheels on chassis
• CPC Class Codes: F16F 15/02 Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems F16F15/005 takes precedence ; layered products B32B; suppression of vibration in ships B63; relieving load on bearings, using magnetic means F16C39/06
• CPC Class Codes: F16F 2224/0283 piezoelectric; electro- or magnetostrictive
• CPC Class Codes: F16F 2224/045 magnetorheological
• CPC Class Codes: F16F 7/01 using friction between loose particles, e.g. sand

Abstract

A lift truck includes systems and methods for improved vibration control. Vibration control features reduce or eliminate motion of the truck in one or more of the X-axis, Y-axis, and Z-axis. Some embodiments may include, alone or in combination with the vibration control, stability control to further stabilize the motion of the truck.

Claims

1. A lift truck having vibration control, the lift truck comprising:

a tractor unit;

vertically movable forks mounted relative to the tractor unit, the forks being vertically movable between an upper position and a lower position;

a vertical support mounted relative to the tractor unit, and a platform mounted relative to the vertical support, the platform for mounting electrical components;

a first sensor to provide a first value of motion of the lift truck in at least one of an X-axis and a Y-axis and a Z-axis; and

the vertical support comprising a hollow tube at least partially filled with a vibration damping material to damper vibrations from reaching the platform.

2. The lift truck as set forth in claim 1 wherein the first sensor comprises a first accelerometer.

3. The lift truck as set forth in claim 2 wherein the first accelerometer is mounted relative to the platform.

4. The lift truck as set forth in claim 1 further including a second sensor to provide a second value of motion of the lift truck in at least one of the X-axis and the Y-axis and the Z-axis.

5. The lift truck as set forth in claim 4 wherein the second sensor comprises a second accelerometer.

6. The lift truck as set forth in claim 5 wherein the second accelerometer is mounted relative to the tractor unit.

7. The lift truck as set forth in claim 1 wherein the hollow tube includes at least one hollow portion separated by a damper section, the damper section containing the vibration damping material.

8. The lift truck as set forth in claim 7 wherein the vibration damping material comprises at least one of a magneto-rheological fluid, a piezoelectric material, an electroactive polymer, and a granular material.

9. The lift truck as set forth in claim 7 wherein the at least one hollow section contains a granular material.

10. The lift truck as set forth in claim 1 further including a mounting frame base, the vertical support mounted relative to the mounting frame base.

11. The lift truck as set forth in claim 4 further including control circuitry coupled to at least one of the first and second sensors and the vibration damping material to control a degree of vibration damping.

12. The lift truck as set forth in claim 11 wherein the vibration damping material is a phase changing material.

13. The lift truck as set forth in claim 11 further including at least one caster mounted relative to the tractor unit;

and

an actuator to lock movement of the caster on a side of the lift truck based on a direction that the control circuitry determined the lift truck to be moving.

14. A lift truck having vibration control, the lift truck comprising:

a tractor unit;

vertically movable forks mounted relative to the tractor unit, the forks being vertically movable between an upper position and a lower position;

a vertical support mounted relative to the tractor unit, and a platform mounted relative to the vertical support, the platform for mounting electrical components;

the vertical support comprising two or more cylinders that function as a mass-damper system to damper vibrations from reaching the platform, the mass-damper system include a spring, a fluid, and a variable valve; and

control circuitry coupled to the variable valve, the control circuitry to control a flow of the fluid through the variable valve to control a degree of vibration damping.

15. The lift truck as set forth in claim 14 further including a sensor coupled to the control circuitry, the sensor to provide a value of motion of the lift truck in at least one of an X-axis and a Y-axis and a Z-axis.

16. The lift truck as set forth in claim 15 wherein the sensor comprises an accelerometer.

17. The lift truck as set forth in claim 16 wherein the accelerometer is mounted relative to the platform.

18. The lift truck as set forth in claim 15 wherein the value of motion provided by the sensor is used to control the flow of fluid through the variable valve.

19. The lift truck as set forth in claim 14 further including at least one caster mounted relative to the tractor unit;

and

an actuator to lock movement of the caster on a side of the lift truck based on a direction that the sensor determined the lift truck to be moving.

20. The lift truck as set forth in claim 14 wherein the platform includes positioning equipment.

21. The lift truck as set forth in claim 14 further including a second sensor to provide a second value of motion of the lift truck in at least one of the X-axis and the Y-axis and the Z-axis.

22. The lift truck as set forth in claim 21 wherein the second sensor comprises a second accelerometer.

23. The lift truck as set forth in claim 22 wherein the second accelerometer is mounted relative to the tractor unit.

24. The lift truck as set forth in claim 21 wherein the vertical support further comprises a hollow tube at least partially filled with a vibration damping material to damper vibrations from reaching the platform.

25. The lift truck as set forth in claim 24 wherein the hollow tube includes at least one hollow portion separated by a damper section, the damper section containing the vibration damping material.

26. The lift truck as set forth in claim 25 wherein the vibration damping material comprises at least one of a magneto-rheological fluid, a piezoelectric material, an electroactive polymer, and a granular material.

27. The lift truck as set forth in claim 25 wherein the at least one hollow section contains a granular material.

28. The lift truck as set forth in claim 24 wherein the control circuitry is further coupled to at least one of the first and second sensors and the vibration damping material to control the degree of vibration damping.

29. A lift truck having vibration control, the lift truck comprising:

a tractor unit;

vertically movable forks mounted relative to the tractor unit, the forks being vertically movable between an upper position and a lower position;

a vertical support mounted relative to the tractor unit, and a platform mounted relative to the vertical support, the platform for mounting electrical components;

a first sensor to provide a first value of motion of the lift truck in at least one of an X-axis and a Y-axis and a Z-axis;

the first sensor being an accelerometer mounted relative to the platform;

the vertical support comprising a hollow tube at least partially filled with a vibration damping material to damper vibrations from reaching the platform, the hollow tube including at least one hollow portion separated by a damper section, the damper section containing the vibration damping material; and

the vibration material comprises at least one of a magneto-rheological fluid, a piezoelectric material, an electroactive polymer, and a granular material.

30. A lift truck having vibration control, the lift truck comprising:

a tractor unit;

vertically movable forks mounted relative to the tractor unit, the forks being vertically movable between an upper position and a lower position;

a vertical support mounted to the tractor unit, the vertical support including a first vertical support arm and a second vertical support arm;

a platform mounted on a horizontal support that is mounted between the first vertical support arm and the second vertical support arm, the platform for mounting electrical components;

at least one of the first vertical support arm and the second vertical support arm comprising two or more cylinders that function as a mass-damper system to damper vibrations from reaching the platform, the mass-damper system include a spring, a fluid, and a variable valve;

control circuitry coupled to the variable valve, the control circuitry to control a flow of the fluid through the variable valve to control a degree of vibration damping;

a first sensor coupled to the control circuitry, the first sensor to provide a value of motion of the lift truck in at least one of an X-axis and a Y-axis and a Z-axis; and

a second sensor coupled to the control circuitry, the sensor to provide a second value of motion of the lift truck in the at least one of the X-axis and the Y-axis and the Z-axis.