Thrust sensor assembly

A thrust sensor assembly suitable for use with an actuator of the type wherein motive power is applied to an actuator shaft and wherein the thrust sensor assembly comprises a first compression plate means and a second compression plate means, at least one of said compression plate means being engageable with said shaft to move axially with said shaft and the second compression plate means being arranged to oppose the first compression plate means with at least one resiliently compressible, substantially elastomeric pad sandwiched therebetween, a pressure transducer being mounted on one of said compression plate means, said at least one pad having a contact face with a contact area facing said one of the compression plate means having said pressure transducer mounted thereon whereby the sensor assembly is arranged so that movement of the first compression plate means towards the second compression plate means compresses said elastomeric pad between said first and second compression plate means with only part of the contact area of the pad pressing against the pressure transducer and thereby inducing a signal from said pressure transducer that corresponds to the thrust of said actuator shaft, the thrust sensor assembly being configured such that the total contact area of the surface of said compressible pad facing said one of said compression plate means bearing the pressure transducer is selectively variable to alter the proportion of thrust transmitted to the transducer by replacing said pad with at least one other differently sized pad or different number of said pad, whereby the sensor assembly accommodates a wide range of actuator thrusts while maintaining the pressure applied to said pressure transducer within the operating range of said pressure transducer.