Patent ID: 6018241
Filing Date: 2000-01-25
Classification: G01B,G01D

Abstract:
A sensor for detecting a position of a movable piece relative to a reference point, comprising:a) a c-shaped magnetically permeable bracket, attached to the movable piece and having a first and second spaced apart flanges disposed opposite and parallel to each other, the first and second flanges interconnected by a central flange and a distal end;b) a first and second tapered opposed magnet attached to the first and second flanges and extending along the length thereof, respectively, each tapered magnet having:b1) an inclined surface having a thin end located substantially at the distal end of the flanges; andb2) a plateau located substantially at the proxil end of the flanges;c) a variable width air gap being defined between the inclined surfaces of the first and second tapered magnets, the first and second tapered magnets, the bracket and the air gap forming a continuous magnetic circuit and producing a variable magnetic field density within the air gap that varies from a low magnitude near the distal end of the flanges to a high magnitude near the proxil end of the flanges; andd) at least one hall effect magnetic field detector fixedly positioned in the variable width air gap between the first and second magnets for generating an electrical signal representative of the position of the movable piece with respect to the reference point.