1. Field of the Invention
This invention relates generally to position transducers, and more particularly to non-contact position transducers with Hall-effect position sensing.
2. Description of the Related Art
Prior art position transducers include a shaft that pivots or rotates with respect to a stationary housing. The shaft is typically connected to a wiper mechanism that brushes against a resistor strip when the shaft is rotated. The wiper mechanism, when rotated, causes a change in electrical resistance to thereby indicate the relative rotational position of the shaft with respect to the housing. Although relatively inexpensive in construction, position transducers of this type are subject to wear due to the sliding effect of the wiper against the resistor strip. Worn parts may result in mechanical breakdown of the transducer or, at the very least, inaccurate position sensing.
In an attempt of overcome such problems, contactless position sensors have been developed. Such position sensors include inductively coupled ratio detectors, capacitively coupled ratio detectors, optical detectors using the Faraday effect, photo-activated ratio detectors, radio wave directional comparators, and electrostatic ratio detectors, among others. These position sensors tend to offer much value for one or more applications, but none meet all application requirements for all position sensing applications. The limitations may be due to high cost, sensitivity to particular energies or fields, instability, resistance to contamination and environment, ruggedness, linearity, precision, and so on.
USPTO Backgrounds
USPTO Backgrounds