Material handler with center of gravity monitoring system

• US 20030060923A1
• Filed: 09/21/2001
• Published: 03/27/2003
• Est. Priority Date: 09/21/2001
• Status: Active Grant

• Current Assignee: Volvo Construction Equipment AB (Volvo AB)
• Original Assignee: Ingersoll-Rand Company (Trane Technologies plc)
• Inventors: Scotese, Michael J.
• Granted Patent: US 6,985,795 B2
• Time in Patent Office: Days
• US Class Current: 700/217
• CPC Class Codes: B60G 17/016 characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input B60G17/017 takes precedence
• CPC Class Codes: B60G 2200/322 with a single pivot point and a straight axle
• CPC Class Codes: B60G 2204/61 Adjustable during maintenance
• CPC Class Codes: B60G 2400/61 Load distribution
• CPC Class Codes: B60G 2400/63 Location of the center of gravity
• CPC Class Codes: B60G 9/02 the axle or housing being pivotally mounted on the vehicle , e.g. the pivotal axis being parallel to the longitudinal axis of the vehicle B60G9/003 takes precedence
• CPC Class Codes: B66C 23/905 electrical
• CPC Class Codes: B66F 17/003 for fork-lift trucks

Abstract

A material handler that includes a frame, first and second front wheels, first and second rear wheels, and a control system. The front and rear wheels define a generally horizontal plane. The control system determines the center of gravity of the material handler and displays the location of the center of gravity of the material handler within the plane.

Claims

1. A material handler comprising:

a frame;

first and second front wheels rotatably coupled to the frame;

first and second rear wheels rotatably coupled to the frame, the front and rear wheels supporting the frame for movement over the ground and defining a plane; and

a control system that determines the center of gravity of the combination of the material handler and any load supported by the material handler and displays the location of the center of gravity within a virtual plane that is a representation of the plane defined by the wheels.

2. The material handler of claim 1, wherein the plane defined by the wheels is substantially horizontal when the material handler is on substantially level ground.

3. The material handler of claim 1, wherein the control system includes a screen and displays the center of gravity with a cursor located on the screen.

4. The material handler of claim 1, wherein the control system includes first, second, third, and fourth sensors that generate signals corresponding to the force that the material handler applies to each wheel.

5. The material handler of claim 4, further comprising a front axle coupled to the frame, the first front wheel being rotatably coupled to a first portion of the front axle and the second front wheel being rotatably coupled to a second portion of the front axle, and a rear axle coupled to the frame, the first rear wheel being rotatably coupled to a first portion of the rear axle and the second rear wheel being rotatably coupled to a second portion of the rear axle, wherein the control system includes a first sensor positioned on the front axle adjacent to the first front wheel, a second sensor positioned on the front axle adjacent to the second front wheel, a third sensor positioned on the rear axle adjacent to the first rear wheel, and a fourth sensor positioned on the rear axle adjacent to the second rear wheel, and wherein the sensors generate signals corresponding to the force that the material handler applies to each wheel.

6. The material handler of claim 5, wherein the front and rear axles include lower king pins located at the first portion of the front axle, the second portion of the front axle, the first portion of the rear axle, and the second portion of the rear axle, and wherein the sensors are located on the lower king pins.

7. The material handler of claim 6, wherein the sensors are strain gauges.

8. The material handler of claim 1, wherein the control system also displays the location of the center of gravity relative to a boundary, the boundary defining a productive zone in which the material handler is stable and an non-productive zone in which the material handler is unstable.

9. The material handler of claim 8, further comprising a front axle coupled to the frame, the first front wheel being rotatably coupled to a first portion of the front axle and the second front wheel being rotatably coupled to a second portion of the front axle, and a rear axle coupled to the frame, the first rear wheel being rotatably coupled to a first portion of the rear axle and the second rear wheel being rotatably coupled to a second portion of the rear axle, wherein the front axle is non-pivotable relative to the frame, wherein the rear axle includes multiple states, and wherein the boundary changes depending on the state of the rear axle.

10. The material handler of claim 9, wherein the rear axle are is freely pivotable relative to the frame and wherein the boundary is generally triangular and represents a line that connects the front wheels and lines that converge from the front wheels to a point located between the rear wheels.

11. The material handler of claim 9, wherein the rear axle pivotable in only one direction relative to the frame and wherein the boundary represents a line that extends from the first front wheel to the second front wheel, from the second front wheel to a point between the first and second rear wheel, from the point to the second rear wheel, and from the second rear wheel to the first wheel.

12. The material handler of claim 9, wherein the rear axle is non-pivotable relative to the frame and wherein the boundary represents a rectangle defined by the first front wheel, the second front wheel, the first rear wheel, and the second rear wheel.

13. The material handler of claim 9, further comprising lockable shock absorber connected to the frame and the rear axle, wherein the lockable shock absorber includes a free state where the lockable shock absorber is freely extendable and retractable and a first fixed state where the lockable shock absorber is prevented from retracting such that the rear axle is only allowed to pivot in one direction, the lockable shock absorber generating a fixed signal when the lockable shock absorber is in the first fixed state.

14. The material handler of claim 13, wherein the control system receives a first fixed signal from the lockable shock absorber and displays a boundary based on the first fixed signal from the lockable shock absorber.

15. The material handler of claim 13, wherein the lockable shock absorber includes a second fixed state where the lockable shock absorber is prevented from retracting such that the rear axle is only allowed to pivot in the opposite direction, the lockable shock absorber generating a second fixed signal when the lockable shock absorber is in the second fixed state.

16. The material handler of claim 15, wherein the control system receives the fixed signals from the lockable shock absorber and displays a boundary based on the fixed signals from the lockable shock absorber.

17. The material handler of claim 8, wherein the control system prevents the execution of material handler functions that would otherwise move the displayed center of gravity from the productive zone into the non-productive zone.

18. The material handler of claim 17, wherein the control system allows material handler functions that move the displayed center of gravity anywhere within the productive zone.

19. The material handler of claim 18, further comprising a telescoping boom coupled to the frame and movable between a retracted position and an extended position, and pivotable between a lowered position and a raised position, wherein the material handler functions include extending and pivoting the boom.

20. A method of monitoring the center of gravity of the combination of a material handler and any load supported by the material handler, the method comprising:

determining the center of gravity of the combination of the material handler and the load; and

displaying the location of the center of gravity of the combination of the material handler and the load within a virtual plane that is a representation of a plane defined by front and rear wheels.

21. The method of claim 20, wherein displaying the location of a center of gravity of the material handler within a virtual plane includes displaying the location of the center of gravity of the material handler within the virtual plane that is a representation of a substantially horizontal plane that is defined by the front and rear wheels.

22. The method of claim 20, wherein displaying the location of a center of gravity of the material handler within a virtual plane includes displaying the location of the center of gravity of the material handler within the virtual plane with a cursor located on a screen.

23. The method of claim 20, wherein determining the center of gravity includes determining the force that the material handler applies to a first front wheel, a second front wheel, a first rear wheel, and a second rear wheel.

24. The method of claim 20, wherein displaying the location of the center of gravity includes displaying the location of the center of gravity relative to a boundary, the boundary defining a productive zone in which the material handler is stable and an nonproductive zone in which the material handler is unstable.

25. The method of claim 24, further comprising changing the boundary depending on whether first and second portions of a rear axle are in a fixed state where the portion is non-pivotable relative to the frame or a free state where the portion is freely pivotable relative to the frame and the other portion of the rear axle.

26. The method of claim 25, wherein displaying the location of the center of gravity relative to a boundary includes displaying a generally triangular boundary that represents a line that connects the front wheels and lines that converge from the front wheels to a point located between the rear wheels when the first and second portions of the rear axle are in the free state.

27. The method of claim 25, wherein displaying the location of the center of gravity relative to a boundary includes displaying a boundary that represents a line that extends from the first front wheel to the second front wheel, from the second front wheel to a point between the first and second rear wheel, from the point to the second rear wheel, and from the second rear wheel to the first wheel when the first portion of the rear axle is in the free state and the second portion of the rear axle is in the fixed state.

28. The method of claim 25, wherein displaying the location of the center of gravity relative to a boundary includes displaying a boundary that represents a rectangle that is defined by the first front wheel, the second front wheel, the first rear wheel, and the second front wheel when the first and second portions of the rear axle are in a fixed state.

29. The method of claim 24, further comprising preventing the execution of material handler functions that would otherwise move the displayed center of gravity from the productive zone into the non-productive zone.

30. The method of claim 29, further comprising allowing material handler functions that move the displayed center of gravity anywhere within the productive zone.

31. The method of claim 30, further comprising providing a telescoping boom coupled to the frame and movable between a retracted position and an extended position, and pivotable between a lowered position and a raised position, wherein preventing the execution of material handler functions includes preventing the telescoping boom from being extended and pivoted.

32. A control system for a material handler that includes a frame, first and second front wheels rotatably coupled to the frame, first and second rear wheels rotatably coupled to the frame, the wheels supporting the frame for movement over the ground and defining a plane, the control system comprising:

four sensors, each sensor adapted to generate a signal indicative of a load applied to a respective one of the wheels of the material handler;

a controller that determines the center of gravity of the combination of the material handler and a load supported by the material handler based on the signals generated by the sensors; and

a display that displays the location of the center of gravity within a virtual plane that is a representation of the plane defined by front and rear wheels.

33. The control system of claim 32, wherein the material handler includes a telescoping boom coupled to the frame and movable between a retracted position and an extended position, and pivotable between a lowered position and a raised position.