Granted Patent B1

US 7,337,912 · App. 11/703,683 · Granted Mar 4, 2008

Abstract

Claims (31)

1. A crane comprising:

a telescoping boom comprising a base boom member and an inner telescopic member slidably mounted in said base boom member and having a first end projecting from said base boom member, said first end of said inner member including a first connector element at a first side thereof and a second connector element at a second side thereof;

a boom extension having a first end and a second end, said boom extension first end including a first attachment element at a first side thereof and a second attachment element at a second side thereof, said boom extension further including first and second spaced bracket assemblies, said first bracket assembly being located between said second bracket assembly and said boom extension first end;

said boom extension being shiftable between a use position wherein said first attachment element is connected to the opening of said first connector element and said second attachment element is connected to said second connector element and a storage position wherein said boom extension is connected to first and second supports on said base boom member;

said first support comprising a holder for pivotably retaining said first bracket assembly;

said second support comprising a rail projecting from said base boom section and a slider slidably supported by said rail; and

an actuator connected between said slider and said boom for shifting said slider between a retracted position and an extended position relative to said base boom member.

2. The crane of claim 1 wherein said rail comprises a planar upper surface and said slider comprises a planar lower surface slidably engaging said rail upper surface.

3. The crane of claim 1 wherein said rail includes a first wear plate mounted on a first rail surface and said slider includes a second wear plate mounted on a first slider surface facing said rail first surface, said first wear plate contacting said first wear plate when said slider is between said retracted position and said extended position.

4. The crane of claim 3 wherein said first wear plate substantially overlies said second wear plate when said slider is in said retracted position.

5. The crane of claim 1 wherein said actuator comprises an electromechanical actuator.

6. The crane of claim 1 wherein said actuator comprises a linear actuator.

7. The crane of claim 1 wherein said actuator comprises an electromechanical screw drive.

8. The crane of claim 1 including a controller in communication with said actuator for remotely controlling said actuator.

9. The crane of claim 8 wherein said controller is positioned adjacent to the boom extension first end with said boom extension in the storage position.

10. The crane of claim 8 wherein said controller comprises an radio-frequency transmitter for sending control signals to said actuator.

11. The crane of claim 8 wherein said controller is connected to said actuator by a wire, said wire extending from said actuator a distance sufficient to position said controller adjacent said first connector element.

12. The crane of claim 1 wherein said first connector element is aligned with said first attachment element when said slider is in a position between the retracted position and the extended position.

13. The crane of claim 1 wherein said first connector element is aligned with said first attachment element when said slider is in said extended position.

14. A method of deploying a boom extension on a telescoping crane boom comprising the steps of:

providing a boom having a base boom member comprising first and second supports, and a telescoping inner member comprising a first end having first and second connector elements, the second support comprising a slider slidably mounted on a rail and shiftable between a retracted and an extended position by an actuator;

providing a boom extension having a first end including a first attachment element and a second attachment element and a second end, and first and second bracket assemblies between the first and second boom extension ends;

connecting the first bracket assembly to the boom first support;

connecting the second bracket assembly to the boom second support so that the first attachment element is spaced from the first connector element;

controlling the actuator to move the slider toward the extended position until the first attachment element is aligned with the first connector element;

connecting the first attachment element to the first connector element;

disconnecting the boom extension from the first and second supports by extending the inner member from the base member;

pivoting the boom extension about the boom extension first connector element until the second attachment element is aligned with the second connector element; and

connecting the second attachment element to the second connector element.

15. The method of claim 14 wherein said step of connecting the first attachment element to the first connector element comprises the step of inserting a pin through aligned openings of the first attachment element and the first connector element.

16. The method of claim 14 wherein said step of controlling the actuator to move the slider toward the extended position comprises the step of powering the actuator to move the slider to the extended position.

Assignments (12)