Granted Patent B1

US 6,994,223 · App. 10/282,343 · Granted Feb 7, 2006

Abstract

Claims (32)

1. A method for controlling the operation of a crane, comprising the steps of:

providing operator controls to allow control of the crane operations by an operator;

using a proportional hydraulic valve to control hydraulic fluid coupled to hydraulic motors that control the crane operations;

periodically monitoring by a control system a hydraulic pressure of a lift mechanism of the crane so as to determine a load condition of the crane;

storing in the control system a plurality of ranges of hydraulic fluid pressures applied to the lift mechanism during various crane operations, including;

a) a first pressure range,

b) a second pressure range higher than said first pressure range, and

c) a third pressure range higher than said second pressure range;

allowing the crane to be operated by the operator without modification when the monitored hydraulic pressure is in said first range;

using the control system to modify crane operations requested by the operator when the monitored hydraulic pressure is in said second pressure range, including using the control system to control the proportional valve to reduce the hydraulic fluid flow therethrough to slow the movements of the crane operations; and

using the control system to deny various crane operations requested by the operator when the monitored hydraulic pressure is in said third pressure range, said various crane operations being denied comprise those crane operations which would increase a moment of a load being lifted by the crane, and said control system allows other crane operations not having an effect of increasing the moment to be carried out when the monitored hydraulic pressure is in said third pressure range.

2. The method of claim 1 , wherein said third pressure range comprises an overload range, and further including allowing the operator to raise a boom of the crane, or retract a telescopic boom of the crane or lower the load when the monitored hydraulic pressure is in said third pressure range.

3. The method of claim 1 , further including providing a hydraulic valve for controlling a movement of each crane apparatus, and supplying pressurized fluid to said hydraulic valves by way of said proportional valve.

4. The method of claim 1 , further including modifying crane operations requested by the operator when the monitored hydraulic pressure is in said second pressure range by modifying the requested speed by which a boom of the crane is lowered.

5. The method of claim 1 , further including providing visual readout indications of different operating conditions of the crane as a function of the monitored hydraulic pressure of the lift mechanism.

6. The method of claim 5 , further including providing a visual readout of an overload condition of the crane when the hydraulic pressure is monitored and determined by said control system as exceeding a predefined threshold.

7. The method of claim 5 , further including providing a first overload readout when a boom of the crane is attempted to be extended or a hoist of the crane is attempted to be activated, and a second overload readout different from said first overload readout when the boom is attempted to be raised or lowered.

8. The method of claim 5 , further including providing a visual readout when said hydraulic pressure is sensed to be less than a predefined amount to thereby prevent damage to a boom of the crane should said boom be resting on a support.

9. The method of claim 1 , further including providing visual readout indications of different operating conditions of the crane as a function of monitored switch sensors of the crane.

10. The method of claim 9 , further including providing a visual readout indicating that a traveling block of the crane has engaged with a crown mechanism of the crane.

11. The method of claim 9 , further including providing a visual readout indicating when a boom of the crane is in a predefined position to be stowed for transportation.

12. The method of claim 9 , further including monitoring hydraulic pressure of the lift mechanism, and providing a visual indication when the hydraulic pressure and the switch sensors indicate that the crane operations are in a normal range.

13. The method of claim 1 , further including:

providing a visual display for displaying status codes, said status codes relating to operational parameters of the crane;

providing said visual display on said crane outside a cab of the crane so as to be visible by an operator using a wireless hand-held transmitter for controlling operation of the crane; and

said visual display associated with a listing of the status codes cross-referenced to problems related to a crane boom position or boom load condition.

14. The method of claim 13 further including providing other visual indications to an operator of the crane as to curative steps to take in response to the visual readouts.

15. The method of claim 13 , further including;

using the control system to sense hydraulic pressure of a lift cylinder that operates to support a load that the crane is lifting, and said control system provides output load indications as a function of the hydraulic pressure; and

sensing sensor switches that sense movements and positions of crane apparatus and providing respective load and position indications of the crane apparatus to said control system.

16. The method of claim 15 , further including:

using a programmable processor programmed to process the load indications and the position indications and providing outputs to said visual display for displaying a status of the operations of the crane, whereby when a status code is displayed said operator can consult said listing to determine a probable cause of a problem relating to a position or loading of the crane boom.

Assignments (12)