Patent ID: 8272521
Filing Date: 2012-09-25
Classification: B66C,B66F

Abstract:
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 independently control hydraulic fluid coupled to hydraulic motors that control the crane operations; periodically monitoring by a control system a hydraulic crane moment load of a lift mechanism of the crane so as to determine a moment load condition of the crane; periodically monitoring by the control system of a boom raising cylinder pressure and boom inclination; periodically monitoring by the control system of the level of a crane chassis; periodically calculating a crane moment load based on the hydraulic boom raising cylinder pressure, boom inclination and crane level; storing in the control system a plurality of ranges of boom raising cylinder pressure and boom inclination angle applied to the lift mechanism during various crane operations, including; a) a first range of crane moment load and, b) a second range of crane moment load, said second range being higher than said first range, and c) a third range of crane moment load, said third range being higher than said second crane moment load range; allowing the crane to be operated by the operator without modification when the crane moment load is in said first range; using the control system to modify crane operations requested by the operator when the crane moment load is in said second crane moment load 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 crane moment load is in said third crane moment load 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 crane moment load is in said third crane moment load range.