Hydraulic stabilizer system and process for monitoring load conditions

• US 6,785,597 B1
• Filed: 02/07/2003
• Issued: 08/31/2004
• Est. Priority Date: 02/07/2003
• Status: Active Grant

• Current Assignee: Wiggins Lift Co., Inc.
• Original Assignee: Wiggins Lift Co., Inc.
• Inventors: Yue, Liming, Farber, Bruce W.
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US10/359,810
• Publication Number:
  US 20040158380A1
• Time in Patent Office: 571 Days
• Field of Search: 177/136, 177/139, 177/140, 177/141, 177/45-47, 702/173, 702/174, 212/276, 212/277, 212/278, 187/222, 187/223, 187/224, 187/233-238, 187/250, 187/391-405, 414/635-636, 414/639-640, 414/474-486, 414/572-573, 414/589-590, 414/809, 701/29, 701/36, 701/50, 701/124, 73/650.1, 73/650.9, 733/82.R, 340/679, 340/684, 340/689, 340/685, 340/438, 340/439, 340/440, 340/450, 340/451, 340/459, 340/460, 340/461
• US Class Current: 701/50
• CPC Class Codes: B66F 17/003 for fork-lift trucks

Abstract

A process for monitoring load conditions on a lifting machine having a rated load moment includes determining an actual load moment of the lifting machine due a weighted load. The actual load moment may be determined by measuring a tilt pressure within a hydraulic tilt cylinder of the lifting machine, and then calculating the actual load moment from the tilt pressure within the hydraulic tilt cylinder. The location of a center of gravity of the weighted load is also determined by measuring a lift pressure within a hydraulic lift cylinder of the lifting machine, and then calculating the weight of the weighted load from the lift pressure. Once the weight is determined, the location of the center of gravity of the weighted load may be found using the actual load moment and the calculated weight. Information about the weight and the location of the center of gravity of the weighted load may be also provided to a user as well as warnings if the operating parameters of the lifting machine are in danger of being exceeded or actually exceeded. If a load pressure switch of the lifting machine is activated, at the very least, the lifting function of the machine will be disabled.

Claims

1. A process for monitoring load conditions on a lifting machine having a rated load moment, comprising the steps of:

determining an actual load moment of the lifting machine due a weighted load, the determining step including the steps of;

measuring a tilt pressure within a hydraulic tilt cylinder of the lifting machine, and calculating the actual load moment from the tilt pressure within the hydraulic tilt cylinder, and

measuring a lift pressure within a hydraulic lift cylinder of the lifting machine, calculating the weight of the weighted load from the lift pressure, and calculating a location of the center of gravity of the weighted load using the actual load moment and the calculated weight;

activating a first warning if the actual load moment is below a first predetermined load moment;

activating a second warning if the actual load moment is above the firs t predetermined load moment and below a second predetermined load moment; and

activating a third warning if the actual load moment is above the second predetermined load moment.

2. The system of claim 1, wherein the first, second, and third warnings are colored lights.

3. The process of claim 1, wherein the first predetermined load moment is 80% to 100% of the rated load moment.

4. The process of claim 1, wherein the second predetermined load moment is 100% to 120% of the rated load moment.

5. The process of claim 1, including the step of engaging an audio alarm if the actual load moment is above the first predetermined load moment and below the second predetermined load moment.

6. The process of claim 1, including the step of engaging an audio alarm if the actual load moment is above the second predetermined load moment.

7. The process of claim 1, including the step of disabling the lifting machine if a load pressure switch of the lifting machine is activated.

8. The process of claim 1, wherein the determining step includes the steps of weighing the weighted load and calculating a location of a center of gravity of the weighted load.

9. The process of claim 8, further including the step of providing information to a user about the weight and the location of the center of gravity of the weighted load, whereby a warning is provided to the user if the load is near the rated load moment of the lifting machine.

10. A process for monitoring load conditions on a lifting machine having a rated load moment, comprising the steps of:

measuring a tilt pressure within a hydraulic tilt cylinder of the lifting machine, and calculating an actual load moment of the lifting machine from the tilt pressure due to a weighted load on the lifting machine;

measuring a lift pressure within a hydraulic lift cylinder of the lifting machine, calculating the weight of the weighted load from the lift pressure and calculating a location of a center of gravity of the weighted load using the actual load moment and the calculated weight;

activating a first warning if the actual load moment is below a first predetermined load moment;

activating a second warning if the actual load moment is above the first predetermined load moment and below a second predetermined load moment;

and activating a third warning if the actual load moment is above the second predetermined load moment.

11. The system of claim 10 engaging a first audio alarm if the actual load moment is above the first predetermined load moment and below the second predetermined load moment, and engaging a second audio alarm if the actual load moment is above the second predetermined load moment.

12. The system of claim 11, wherein the first, second, and third warnings are colored lights.

13. The process of claim 10, wherein the first predetermined load moment is 80% to 100% of the rated load moment.

14. The process of claim 10, wherein the second predetermined load moment is 100% to 120% of the rated load moment.

15. The process of claim 10, including the step of disabling the lifting-machine if a load pressure switch of the lifting machine is activated.

16. The process of claim 10, further including the step of providing information to a user about the weight and the location of the center of gravity of the weighted load, whereby a warning is provided to the user if the load is at least 90% of the rated load moment of the lifting machine.

17. A hydraulic stabilizer system, comprising:

a hydraulic lift having a rated load moment;

a means for measuring pressure within the hydraulic lift;

a processor for determining an actual load moment of the hydraulic lift and for determining a weight of a load on the hydraulic lift based on pressure within the hydraulic lift;

an illuminated display for warning an operator of the hydraulic lift if at least one predetermined operating parameter is exceeded; and

a load pressure switch for disabling the hydraulic lift if another predetermined operating parameter is exceeded;

wherein the hydraulic lift includes a frame, at least one load bearing member operationally connected to the frame for movement relative thereto, a hollow lift cylinder housing a lift piston and hydraulic fluid, the lift cylinder piston operationally connected to the load bearing member, with the hydraulic fluid disposed between the lift piston and one end of the frame, the lift piston imparting a lift force upon the hydraulic fluid within the lift cylinder proportional to a weight associated with the load bearing member, and a hollow tilt cylinder housing a tilt piston and hydraulic fluid, the tilt piston operationally connected to the load bearing member, with the hydraulic fluid within the tilt cylinder disposed between the tilt piston and one end of the frame, the tilt piston imparting a tilt force upon the fluid proportional to an actual load moment associated with the load bearing member; and

wherein the means for measuring pressure within the hydraulic lift is a lift pressure sensor in fluid communication with the hydraulic fluid within the lift cylinder, for measuring pressure of the hydraulic fluid within the lift cylinder for a period of time and creating electrical signals corresponding thereto, defining at least one pressure measurement within the lift cylinder, with the pressure within the lift cylinder being related to the lift force associated with the load bearing member, and a tilt pressure sensor in fluid communication with the hydraulic fluid within the tilt cylinder, for measuring pressure of the hydraulic fluid within the tilt cylinder for a period of time and creating electrical signals corresponding thereto,

defining at least one pressure measurement within the tilt cylinder, with the pressure being related to the tilt force associated with the load bearing member.

18. The system of claim 17, wherein the illuminated display is in data communication with the processor and produces a visual representation of the weight on the hydraulic lift.

19. The system of claim 17, wherein the processor includes a first sub-routine of a program stored in a memory to be operated on by the processor, determining, from at least one pressure measurement within the lift cylinder, the weight of the load on the hydraulic lift.

20. The system of claim 19, wherein the processor includes a second sub-routine of the program stored in the memory to be operated on by the processor, determining, from at least one pressure measurement within the tilt cylinder, the actual load moment of the load on the hydraulic lift.

21. The system of claim 17, the processor includes at least one sub-routine of a program stored in a memory to be operated on by the processor, determining, from at least one pressure measurement within the lift cylinder, the weight of the load on the hydraulic lift, and determining, from at least one pressure measurement within the tilt cylinder, the actual load moment of the load on the hydraulic lift, wherein another sub-routine of the program stored in the memory to be operated on by the processor uses the actual load moment and the weight of the load to determine a location of a center of gravity of the load on the hydraulic lift.

22. The system of claim 17, wherein the illuminated display activates a first warning if the actual load moment is below a first predetermined load moment, activates a second warning if the actual load moment is above the first predetermined load moment and below a second predetermined load moment, and activates a third warning if the actual load moment is above the second predetermined load moment.

23. The process of claim 22, wherein the first predetermined load moment is 80% to 100% of the rated load moment, and the second predetermined load moment is 100% to 120% of the rated load moment.

24. The system of claim 22, wherein the first, second, and third warnings are colored lights.

25. The system of claim 17, wherein the illuminated display engages a first audio alarm if the actual load moment is above a first predetermined load moment and below a second predetermined load moment, and engages a second audio alarm if the actual load moment is above the second predetermined load moment.

26. The process of claim 25, wherein the first predetermined load moment is 80% to 100% of the rated load moment, and the second predetermined load moment is 100% to 120% of the rated load moment.

27. The process of claim 17, wherein the hydraulic lift is disabled if the load pressure switch is activated.

28. A hydraulic stabilizer system, comprising:

a hydraulic lift having a rated load moment and maximum lifting capacity, wherein the hydraulic lift includes a frame, at least one load bearing member operationally connected to the frame for movement relative thereto, a hollow lift cylinder housing a lift piston and hydraulic fluid, the lift cylinder piston operationally connected to the load bearing member, with the hydraulic fluid disposed between the lift piston and one end of the frame, the lift piston imparting a lift force upon the hydraulic fluid within the lift cylinder proportional to a weight associated with the load bearing member, and a hollow tilt cylinder housing a tilt piston and hydraulic fluid, the tilt piston operationally connected to the load bearing member, with the hydraulic fluid within the tilt cylinder disposed between the tilt piston and one end of the frame, the tilt piston imparting a tilt force upon the fluid proportional to an actual load moment associated with the load bearing member;

at least one lift pressure switch in fluid communication with the hydraulic fluid within the lift cylinder, for measuring pressure of the hydraulic fluid within the lift cylinder, with the pressure within the lift cylinder being related to the lift force associated with the load bearing member, and at least one tilt pressure switch in fluid communication with the hydraulic fluid within the tilt cylinder, for measuring pressure of the hydraulic fluid within the tilt cylinder, with the pressure being related to the tilt force associated with the load bearing member;

an illuminated display for warning an operator of the hydraulic lift if at least one predetermined operating parameter is exceeded, wherein the illuminated display is in communication with the at least one lift pressure switch and the at least one tilt pressure switch; and

a load pressure switch for disabling the hydraulic lift if another predetermined operating parameter is exceeded, wherein the lift pressure switch measures the lift force and the tilt pressure switch measures the tilt force, whereby the illuminated display activates a first warning if the actual load moment is below a first predetermined load moment, activates a second warning if the actual load moment is above the first predetermined load moment and below a second predetermined load moment, activates a third warning if the actual load moment is above the second predetermined load moment, and disables the hydraulic lift if the weight is above the maximum lifting capacity.

29. The process of claim 28, wherein the first predetermined load moment is 80% to 100% of the rated load moment, and the second predetermined load moment is 100% to 120% of the rated load moment.

30. The system of claim 28, wherein the first, second, and third warnings are colored lights.

31. The system of claim 28, wherein the illuminated display engages a first audio alarm if the actual load moment is above a first predetermined load moment and below a second predetermined load moment, and engages a second audio alarm if the actual load moment is above the second predetermined load moment.

32. The process of claim 28, wherein the hydraulic lift is disabled if the load pressure switch is activated.

33. A hydraulic stabilizer system, comprising:

a hydraulic lift having a rated load moment and maximum lifting capacity, wherein the hydraulic lift includes a frame, at least one load bearing member operationally connected to the frame for movement relative thereto, a hollow lift cylinder housing a lift piston and hydraulic fluid, the lift cylinder piston operationally connected to the load bearing member, with the hydraulic fluid disposed between the lift piston and one end of the frame, the lift piston imparting a lift force upon the hydraulic fluid within the lift cylinder proportional to a weight associated with the load bearing member, and a hollow tilt cylinder housing a tilt piston and hydraulic fluid, the tilt piston operationally connected to the load bearing member, with the hydraulic fluid within the tilt cylinder disposed between the tilt piston and one end of the frame, the tilt piston imparting a tilt force upon the fluid proportional to an actual load moment associated with the load bearing member;

at least one tilt pressure switch in fluid communication with the hydraulic fluid within the tilt cylinder, for measuring pressure of the hydraulic fluid within the tilt cylinder, with the pressure being related to the tilt force associated with the load bearing member;

an illuminated display for warning an operator of the hydraulic lift if at least one predetermined operating parameter is exceeded, wherein the illuminated display is in communication with the at least one tilt pressure switch; and

a load pressure switch for disabling the hydraulic lift if the predetermined operating parameter is exceeded, wherein the tilt pressure switch measures the tilt force, whereby the illuminated display activates a warning if the actual load moment is above a predetermined load moment.

34. The process of claim 33, wherein the predetermined load moment ranges from 100% to 150% of the rated load moment.

35. The system of claim 33, wherein the warning is a colored light.

36. The system of claim 33, wherein the illuminated display engages an audio alarm if the actual load moment is above the predetermined load moment.

37. The process of claim 33, wherein the hydraulic lift is disabled if the load pressure switch is activated.

38. A hydraulic stabilizer system, comprising:

a hydraulic lift having a rated load moment;

a means for measuring pressure within the hydraulic lift;

a processor for determining an actual load moment of the hydraulic lift and for determining a weight of a load on the hydraulic lift based on pressure within the hydraulic lift, the processor including at least one subroutine of a program stored in a memory to be operated on by the processor, determining, from at least one pressure measurement within the lift cylinder, the weight of the load on the hydraulic lift, and determining, from at least one pressure measurement within the tilt cylinder, the actual load moment of the load on the hydraulic lift, wherein another sub-routine of the program stored in the memory to be operated on by the processor uses the actual load moment and the weight of the load to determine a location of a center of gravity of the load o the hydraulic lift;

an illuminated display for warning an operator of the hydraulic lift if at least one predetermined operating parameter is exceeded; and

a load pressure switch for disabling the hydraulic lift if another predetermined operating parameter is exceeded.

39. The system of claim 38, wherein the hydraulic lift includes a frame, at least one load bearing member operationally connected to the frame for movement relative thereto, a hollow lift cylinder housing a lift piston and hydraulic fluid, the lift cylinder piston operationally connected to the load bearing member, with the hydraulic fluid disposed between the lift piston and one end of the frame, the lift piston imparting a lift force upon the hydraulic fluid within the lift cylinder proportional to a weight associated with the load bearing member, and a hollow tilt cylinder housing a tilt piston and hydraulic fluid, the tilt piston operationally connected to the load bearing member, with the hydraulic fluid within the tilt cylinder disposed between the tilt piston and one end of the frame, the tilt piston imparting a tilt force upon the fluid proportional to an actual load moment associated with the load bearing member.

40. The system of claim 39, wherein the means for measuring pressure within the hydraulic lift is a lift pressure sensor in fluid communication with the hydraulic fluid within the lift cylinder, for measuring pressure of the hydraulic fluid within the lift cylinder for a period of time and creating electrical signals corresponding thereto, defining at least one pressure measurement within the lift cylinder, with the pressure within the lift cylinder being related to the lift force associated with the load bearing member, and a tilt pressure sensor in fluid communication with the hydraulic fluid within the tilt cylinder, for measuring pressure of the hydraulic fluid within the tilt cylinder for a period of time and creating electrical signals corresponding thereto, defining at least one pressure measurement within the tilt cylinder, with the pressure being related to the tilt force associated with the load bearing member.

41. The system of claim 38 wherein the illuminated display is in data communication with the processor and produces a visual representation of the weight on the hydraulic lift.

42. The system of claim 38, wherein the processor includes a first sub-routine of a program stored in a memory to be operated on by the processor, determining, from at least one pressure measurement within the lift cylinder, the weight of the load on the hydraulic lift.

43. The system of claim 42, wherein the processor includes a second subroutine of the program stored in the memory to be operated on by the processor, determining, from at least one pressure measurement within the tilt cylinder, the actual load moment of the load on the hydraulic lift.

44. The system of claim 38, wherein the illuminated display activates a first warning if the actual load moment is below a first predetermined load moment, activates a second warning if the actual load moment is above the first predetermined load moment and below a second predetermined load moment, and activates a third warning if the actual load moment is above the second predetermined load moment.

45. The process of claim 44, wherein the first predetermined load moment is 80% to 100% of the rated load moment, and the second predetermined load moment is 100% to 120% of the rated load moment.

46. The system of claim 44, wherein the first, second, and third warnings are colored lights.

47. The system of claim 38, wherein the illuminated display engages a first audio alarm if the actual load moment is above a first predetermined load moment and below a second predetermined load moment, and engages a second audio alarm if the actual load moment is above the second predetermined load moment.

48. The process of claim 47, wherein the first predetermined load moment is 80% to 100% of the rated load moment, and the second predetermined load moment is 100% to 120% of the rated load moment.

49. The process of claim 38, wherein the hydraulic lift is disabled if the load pressure switch is activated.