Patent ID: 7603734
Filing Date: 2009-10-20
Classification: B64F

Abstract:
1. A method for preventing a rack fault condition of a passenger boarding bridge, the passenger boarding bridge having a first electromechanical screw jack and a second electromechanical screw jack mounted one each adjacent opposite sidewall surfaces thereof, the method comprising: using a first electromagnetic sensor, sensing a number of rotations of the first electromechanical screw jack during a known period of time; using a second electromagnetic sensor, sensing a number of rotations of the second electromechanical screw jack during the known period of time; determining a difference between the number of rotations of the first electromechanical screw jack and the number of rotations of the second electromechanical screw jack during the known period of time; and, when the determined difference is outside a predetermined range of threshold values, providing a control signal for changing a rate of rotation of at least one of the first electromechanical screw jack and the second electromechanical screw jack.