Patent ID: 7198140

Claim:
A controllable brake, comprising: (a) a rotor manufactured from magnetically permeable material and shaped to have a working portion on its periphery which extends parallel to a shaft on which said rotor is mounted; (b) a shaft having said rotor connected thereto at one end of the shaft in a manner to restrain relative rotation therebetween; (c) a brake housing having a first sealed chamber rotatably housing the rotor therein, and including a magnetic field generator spaced from the rotor, and configured and positioned for generating a magnetic flux in a direction perpendicular to the shaft and to the working portion of the rotor, and said brake housing including a second sealed chamber, said brake housing second sealed chamber housing a brake control electronics system for controlling and monitoring an operation of the brake; and (d) a controllable magnetic field responsive material contained within said brake housing first sealed chamber in contact with at least the working portion of the rotor ,said magnetic field responsive material having a rheology, the rheology of said magnetic field responsive material being affected by said magnetic field generator, and said brake control electronics system housed in said brake housing second sealed chamber includes a sensor for detecting a relative rotational position of the rotor, and a control electronic circuit for control of the magnetic field generator to apply a magnetic field whose strength is determined by the relative rotational position of the rotor.