Patent ID: 7201366

Claim:
An electronic winch monitoring system for a winch mechanism including a gearbox of predetermined fixed ratio between a rotatable input shaft and a rotatable output shaft, a primary brake operatively connected to the input shaft for selectively stopping rotational motion of the input shaft when activated, a rotatable winch drum operatively connected to the output shaft to rotate therewith for selectively winding on and winding off cable stored on the drum to hoist and lower loads, respectively, and an auxiliary brake operatively connected to the output shaft for selectively stopping, when activated, rotational motion of the winch drum independent of the action of the primary brake, the electronic winch monitoring system comprising: an input speed sensor for detecting an actual rotational speed of the input shaft and producing input speed signals indicative of thereof; an output speed sensor for detecting an actual rotational speed of the output shaft and producing output speed signals indicative thereof; a sensor for determining a currently selected hoisting direction and producing hoisting direction signals indicative thereof; an electronic control unit including a monitoring section and a brake control section; the monitoring section receiving the input speed signals, output speed signals and hoisting direction signals, and processing the speed signals and hoisting direction signals to produce a calculated position of the end of the cable, the monitoring section further processing the speed signals to produce a calculated ratio of the actual rotational speed of the input shaft to the actual rotational speed of the output shaft, and producing a fault indication signal when the value of the difference between the calculated ratio and the predetermined fixed ratio exceeds a predetermined acceptable range value; and the brake control section, upon receiving the fault indication signal, activating the auxiliary brake to stop rotation of the drum with an acceleration profile based on output speed signals and hoisting direction signals received prior to the fault indication signal.