Sensing mirror position in a powered mirror positioning system

The present invention relates to powered systems for adjusting the position of a motor vehicle rearview mirror and particularly relates to such systems where it is desired to automatically move the mirror to a predetermined position in response to a sensed condition. Such automatic mirror adjustment systems are employed to adjust the mirrors outwardly to a predetermined setting for the particular driver identified by an individual code for that driver inputted to the mirror control system through insertion of the key in the ignition switch and also for lowering the mirrors to cover the ground adjacent and behind the vehicle upon the vehicle being placed in reverse gear for backing. An axial lead screw having one end pivotally connected to a rearview mirror is threadedly engaged by a motor driven worm gear, which upon rotation effects axial movement of the lead screw. A pair of flux collectors are disposed on opposite sides of the lead screw adjacent the distal end. A Hall effect sensor is disposed in one of the flux collectors. The distal end of the lead screw is magnetized and the Hall effect sensor provides a signal indicative of the lead screw movement. In one embodiment, the lead screw is magnetized; and, in another embodiment a permanent magnet is inserted in a bore in the distal end of the lead screw.