System for monitoring load and angle for mobile lift device

• US 20080019815A1
• Filed: 10/31/2005
• Published: 01/24/2008
• Est. Priority Date: 10/05/2005
• Status: Active Grant

• Current Assignee: Oshkosh Corporation
• Original Assignee: Oshkosh Corporation
• Inventors: Addleman, Jeffrey L., Harris, Steven C., Spain, Stanley R.
• Granted Patent: US 7,489,098 B2
• Time in Patent Office: Days
• US Class Current: 414/563
• CPC Class Codes: B66C 23/80 hydraulically actuated
• CPC Class Codes: B66C 23/905 electrical
• CPC Class Codes: Y10S 388/909 Monitoring means

Abstract

A mobile lift device having a load moving device capable of engaging a load is provided. The mobile lift device includes one or more systems for stabilizing the mobile lift device during operation of the load moving device. According to one exemplary embodiment, the mobile lift device is a heavy duty wrecker having a rotatable boom assembly. The heavy duty wrecker comprises a monitoring system for stabilizing the wrecker during operation of the boom assembly. The monitoring system comprises a plurality of sensors and a monitoring circuit coupled to the sensors to generate a force signal representative of at least one force being applied to the wrecker based upon the transmitted signals.

Claims

1. A monitoring system for monitoring a force at a load moving device which uses at least one cable attached to a load to lift or slide the load, the system comprising:

a first angle sensor configured to generate a first angle signal representative of a first angle of the cable relative to the device;

a second angle sensor configured to generate a second angle signal representative of a second angle of the cable relative to the device; and

a monitoring circuit coupled to the first and second angle sensors to generate a force signal representative of at least one force being applied to the load moving device based upon the angle signals.

2. The monitoring system of claim 1, wherein the monitoring circuit includes a programmed digital processor.

3. The monitoring system of claim 2, wherein the angle sensors include potentiometers.

4. The monitoring system of claim 2, wherein the angle sensors include encoders.

5. The monitoring system of claim 2, wherein the angle sensors include low-g accelerometers.

6. The system of claim 1, wherein the load moving device includes a boom supported by a structure including a plurality of outriggers for stabilizing the structure, the monitoring system further comprising:

at least one load sensor coupled to the monitoring circuit and configured to generate a load signal representative of a force applied to the outrigger, such that the force signal is generated by the monitoring circuit based upon the angle and load signals.

7. The system of claim 6, wherein the load sensor includes a load cell coupled to the outrigger.

8. The system of claim 6, wherein the outriggers include hydraulic cylinders which are pressurized to stabilize the structure, the load sensors including pressure transducers for sensing a pressure representative of the pressure in the hydraulic cylinders.

9. The system of claim 1, wherein the load moving device includes a boom supported by a structure and the boom is extendable between at least a short length and a long length, the monitoring system further comprising:

at least one length sensor coupled to the monitoring circuit and configured to generate a extension signal representative of the extension of the boom, such that the force signal is generated by the monitoring circuit based upon the extension and load signals.

10. The system of claim 9, wherein the load moving device includes a rotator for supporting the boom relative to the structure to permit rotation of the boom relative to the structure along a first axis and a second axis perpendicular to the first axis, the monitoring system further comprising:

a first axis angle sensor coupled to the monitoring circuit to generate a first axis angle signal representative of an angle of the boom relative to the structure along the first axis.

11. The monitoring system of claim 10, wherein the monitoring circuit includes a programmed digital processor.

12. The monitoring system of claim 11, wherein the axis angle sensors include potentiometers.

13. The monitoring system of claim 11, wherein the axis angle sensors include encoders.

14. The monitoring system of claim 11, wherein the axis angle sensors include low-g accelerometers.

15. A mobile lift device, the device comprising:

a chassis for movement over a surface;

a rotator supported by the chassis;

a boom coupled to the rotator to permit the boom to pivot about at least two axes relative to the chassis;

a first hydraulic operator coupled to the boom to pivot the boom relative to the rotator;

a second hydraulic operator coupled to the rotator to rotate the rotator relative to the chassis;

a plurality of outriggers coupled to the chassis to provide stabilization of the chassis during load handling;

a sheave supported at the distal end of the boom, the sheave rotatably supported to rotate about at least two axes relative to the boom;

a first hoist supported at the rotator;

a cable supported by the first hoist and the first sheave;

a first angle sensor configured to generate a first angle signal representative of a first angle of the cable relative to the boom;

a second angle sensor configured to generate a second angle signal representative of a second angle the cable relative to the boom; and

a monitoring circuit coupled to the first and second angle sensors to determine at least one force applied to the device based at least upon the angle signals and determining whether the force is sufficient to tip the mobile lift device.

16. The device of claim 15, further comprising a device coupled to the monitoring circuit and configured to generate a tension signal representative of the tension of the cable, wherein the force is further determined based upon the tension signal.

17. The device of claim 16, further comprising:

a hydraulic fluid control coupled to the first hydraulic operator and the monitoring circuit, wherein the control controls the flow of hydraulic fluid to the first hydraulic operator in accordance with the determination of the monitoring circuit.

18. The device of claim 17, wherein the flow of hydraulic fluid is substantially terminated when the force is within a predetermined range below that sufficient to tip or overload the device.

19. The device of claim 18, wherein the boom includes a plurality of sections which are translatable relative to each other to along a longitudinal axis to provide extension and retraction of the boom between a first and second length.

20. The device of claim 18, further comprising a rotator angle sensor coupled to the rotator to generate a rotator angle signal representative of the orientation of the rotator relative to the device, the monitoring circuit being coupled to the rotator angle sensor and determining the force applied to the device further based upon the rotator angle signal.

21. The device of claim 18, further comprising at least one outrigger coupled to the chassis to stabilize the chassis and an outrigger sensor coupled to the outrigger to generate an outrigger signal representation of the force between the outrigger and the chassis, the monitoring circuit being coupled to the outrigger sensor and determining the force applied to the device further based upon the outrigger signal.

22. A tow vehicle for handling loads such as disabled automobiles, trucks and equipment, the vehicle comprising:

a chassis;

a rotator supported by the chassis;

an extendable boom coupled to the rotator to permit the boom to pivot about at least two axes relative to the chassis, wherein the boom is extendable between a first length and a second length;

a first hydraulic operator coupled to the boom to pivot the boom relative to the rotator;

a second hydraulic operator coupled to the rotator to rotate the rotator relative to the chassis;

a plurality of outriggers coupled to the chassis to provide stabilization of the chassis during load handling;

a first sheave supported at the distal end of the boom, the first sheave rotatably supported to rotate about at least two axes relative to the boom;

a second sheave supported at the distal end of the boom proximate the first sheave, the second sheave rotatably supported to rotate about at least two axes relative to the boom;

a first hoist supported at the rotator;

a second hoist supported at the rotator;

a first cable supported by the first hoist and the first sheave;

a second cable supported by the second hoist and the second sheave;

a first angle sensor configured to generate a first angle signal representative of a first angle of the first cable relative to the boom;

a second angle sensor configured to generate a second angle signal representative of a second angle the first cable relative to the boom; and

a monitoring circuit coupled to the first and second angle sensors to determine at least one force applied to the vehicle based at least upon the angle signals and determining whether the force is sufficient to tip or overload the tow vehicle.

23. The tow vehicle of claim 22, further comprising:

a hydraulic fluid control coupled to the first hydraulic operator and the monitoring circuit, wherein the control controls the flow of hydraulic fluid to the first hydraulic operator in accordance with the determination of the monitoring circuit.

24. The tow vehicle of claim 23, wherein the flow of hydraulic fluid is substantially terminated when the force is within a predetermined range below that sufficient to tip or overload the tow vehicle.

25. The tow vehicle of claim 23, further comprising:

a third angle sensor coupled to the monitoring circuit and configured to generate a third angle signal representative of a first angle of the first cable relative to the boom; and

a second angle sensor coupled to the monitoring circuit and configured to generate a fourth angle signal representative of a second angle of the first cable relative to the boom;

wherein the monitoring circuit determines the force applied to the vehicle based also on the third and fourth angle signals.

26. The tow vehicle of claim 25, further comprising a rotator angle sensor coupled to the rotator to generate a rotator angle signal representative of the orientation of the rotator relative to the vehicle, the monitoring circuit being coupled to the rotator angle sensor and determining the force applied to the vehicle further based upon the rotator angle signal.

27. The tow vehicle of claim 25, further comprising an outrigger sensor coupled to the outrigger to generate an outrigger signal representative of the force between the outrigger and the vehicle, the monitoring circuit being coupled to the outrigger sensor and determining the force applied to the vehicle further based upon the outrigger signal.

28. The tow vehicle of claim 25, wherein the flow of hydraulic fluid is substantially terminated when the force is within a predetermined range below that sufficient to tip or overload the tow vehicle.