HALL-EFFECT KEY-POSITION SENSOR FOR MOTOR-VEHICLE LATCH

摘要

A lock system has a lock cylinder pivotal about an axis between a pair of end positions and through a center starting position, a key fittable into the cylinder and actuatable to pivot the cylinder between its positions, an arcuate magnet centered on the axis and coupled to the cylinder for joint movement therewith, and a pair of angularly spaced Hall-effect sensors adjacent the magnet, trippable by the magnet to generate respective outputs, and positioned such that in the central position the magnet is closely juxtaposed with and trips both sensors, in one of the end positions the magnet is closely juxtaposed with and trips only one of the sensors and is spaced from the other of the sensors, and in the other end position the magnet is closely juxtaposed with and trips only the other sensor and is spaced from the one sensor. The sensors and magnet are so constructed and relatively positioned that on pivoting of the magnet through a predetermined angle in one direction from the center position the one sensor is tripped and on pivoting of the magnet through the predetermined angle in the other direction the other sensor is not tripped. A lock system connected to the sensors has an antitheft mode initiated by the sensors on displacement of the cylinder into the antitheft end positions and provided with alatch operable on displacement of the cylinder into the lock/unlock end position.