Steering system for crane

Abstract

A steering system (10) for a vehicle, such as a gantry crane (12). The gantry crane (12) generally includes a support structure (14) having a first front wheel (32) and a second opposing front wheel (36) connected proximate a front portion of the crane (12), and a first rear wheel (30) and a second opposing rear wheel (34) connected proximate a rear portion of the crane (12). A control system connected to the crane includes a user interface (111) electronically coupled to a command potentiometer (114) and a programmable controller responsive to the command potentiometer for controlling the angular position of each of the first front wheel (32), the second front wheel (36), the first rear wheel (30) and the second rear wheel (34) to effect a steering mode selected through the user interface (111).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]None.FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]None.TECHNICAL FIELD[0003]The invention relates to steering systems for cranes and, more particularly, to a four-wheel steering system for a gantry crane.BACKGROUND OF THE INVENTION[0004]Steering systems for industrial cranes such as gantry cranes are well known in the art. Gantry cranes are used for lifting and transporting large cargo containers to and from railroad cars, truck trailers and other locations as well as for lifting and transporting boats. An operator utilizes the steering system to navigate the gantry crane through rail yards, warehouses, boat yards or other locations. While the steering systems according to the prior art provide a number of advantageous features, they nevertheless have certain limitations.[0005]The present invention is provided to overcome certain of these limitations and other drawbacks of the prior art, and to provide advantages and aspects not provi...

AI Technical Summary

Benefits of technology

[0008]The steering system is configured to implement a number of safety features. The crane includes an engine for driving the wheels connected to the crane which is capable of operation at a variety of different RPMs. In one embodiment, the control system includes a sensor coupled to the engine and the controller for providing the controller with an operating RPM of the engine. The controller is configured so that if the operating RPM is lower than a predetermined amount, the controller adjusts the rate of change of the angular position of each wheel. The controller slows down the rate of turning of each wheel to coincide with the sensed engine RPM.

[0010]The controller is also programmed to slow down movement of the crane before effecting a carousel steering mode selected through the user interface. To position the wheels of the crane into the proper steering position for the carousel mode as efficiently as possible, the controller is programmed to move the angular position of each wheel one of clockwise and counter clockwise, to effect the smallest amount of angular movement necessary.

[0017]The controller is further configured to monitor the drive engine RPM rate. The controller lowers a rate of turning each wheel to a desired position for the selected steering mode upon sensing a low RPM rate.

Problems solved by technology

While the steering systems according to the prior art provide a number of advantageous features, they nevertheless have certain limitations.