Mechanically adjustable linear-output angular position sensor

TL;DR: An angular position sensor for sensing the angular position of a pivotally mounted device includes a magnetically sensitive device, such as a Hall effect IC, and a plurality of flux concentrators, rigidly disposed relative to the Hall Effect IC, forming an assembly as mentioned in this paper.

Abstract: An angular position sensor for sensing the angular position of a pivotally mounted device includes a magnetically sensitive device, such as a Hall effect IC, and a plurality of flux concentrators, rigidly disposed relative to the Hall effect IC, forming an assembly. The assembly is disposed in a housing a fixed distance from a rotatably mounted standard magnet defining a fixed air gap therebetween. The magnet is disposed in rotatably mounted magnet holder which also acts as a drive arm that is adapted to be mechanically coupled to a pivotally mounted device. The configuration of the flux concentrators assembled to the magnetically sensitive device cause the output of the Hall effect IC to be generally linear. In order to avoid problems associated with electrically adjustable angular position sensors, the angular position sensor in accordance with the present invention is adjusted mechanically. In particular, a flux concentrator, preferably having a halo shape, is disposed adjacent the magnet. The sensor is calibrated by varying the distance between the halo-shaped flux concentrator and the magnet. In one embodiment of the invention, the halo-shaped flux concentrator is formed to provide temperature compensation for the sensor. The sensor is hermetically sealed and is thus unaffected by wear or vibration. In an alternative embodiment, a circular magnet with a central aperture is utilized. In order to reduce the overall length of the sensor, the magnetic sensing element is disposed within the central aperture.