Patent ID: 6994223
Filing Date: 2006-02-07
Classification: B66C

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 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; 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.