Abstract: A muscle exercise and/or rehabilitation apparatus includes a fixture against which a force can be applied; a sensor which senses the force applied to the fixture and produces a load signal corresponding thereto; a speed detector which produces a velocity signal corresponding to the speed of the fixture; a servo motor which produces a rotational output of an output shaft thereof; a closed loop servo circuit which controls the motor in response to the load signal and the velocity signal to control rotation of the output shaft of the servo motor; and a conversion device connected between the fixture and the output shaft of the servo motor for translating the rotational output of the output shaft to linear motion of the fixture, the conversion device including a frame formed by a base, two spaced vertical support bars extending upwardly from the base, and an upper cap securing upper ends of the vertical support bars together, two vertical guide rods supported by the frame, a slide movable along the guide rods in

Abstract: A back attachment for a muscle exercise and/or rehabilitation apparatus of the type having a motor driven output shaft with a central axis, includes seat for supporting a person thereon; a back exercising frame connected to the output shaft for pivoting the back of the person about the central axis when the person is seated in the seat; a support stand for fixedly supporting the seat at a downward angle of approximately 15 degrees toward a front portion of the seat, regardless of the angle of pivot of the back exercising frame; securing straps for securing the person to the seat and back exercising frame; an adjustable foot rest connected to the seat for supporting the feet of the person, during pivoting the back exercising frame, the adjustable foot rest being adjustable along the length thereof toward and away from the seat; a lumbar support connected with the back exercising frame for supporting the lumbar region of the person about an axis offset from the central axis, during pivoting movement of the back

Abstract: A muscle exercise and rehabilitation apparatus includes a movable fixture against which an actuating force can be applied; a particle brake clutch for applying a braking force to the fixture in linear dependence on a braking current supplied thereto, in counteracting relation to the actuating force; a control circuit for controlling the supply of braking current to the particle brake clutch so that the latter controls the fixture to move in at least one of an isometric, isotonic and isokinetic mode of operation; and a hysteresis compensating circuit for supplying a reverse current to the particle brake clutch to cancel out hysteresis in the particle brake clutch in dependence on the amount of braking current previously supplied to the particle brake clutch.

Abstract: A muscle exercise and rahabilitation apparatus includes a movable fixture against which a force can be applied; a servo motor having an output shaft coupled to the fixture; a strain gauge effectively coupled between the output shaft and the fixture for producing a load signal corresponding to the force applied to the fixture; a speed detector for producing a velocity signal corresponding to the speed of the fixture; a closed loop servo circuit for controlling the motor in response to the load and velocity signals to regulate the velocity of the fixture; a limit circuit for preventing movement of the fixture past opposite limits; a storage circuit for storing limit signals corresponding to each limit; a limit setting circuit for enabling the storage circuit to store each limit upon movement of the fixture thereto; a position sensing circuit for producing a position signal corresponding to the position of the fixture; a deceleration circuit for slowing down movement of the fixture as the fixture approaches each

Abstract: A muscle exercise and rehabilitation apparatus comprises a movable arm against which a force can be applied; a servo motor mechanically coupled to the arm through a gear reducer; a sensing device for sensing the force applied to the arm and for producing a load signal corresponding thereto; a tachometer for producing a velocity signal corresponding to the velocity of the arm; a closed loop velocity servo feedback circuit for controlling the motor in response to a control signal and the velocity signal so that the arm has a constant resistive torque applied thereto and/or has its velocity regulated, regardless of the force applied to the arm, the feedback circuit including an amplifier for amplifying the load signal to produce the control signal, a torque control circuit and a speed clamp circuit for modifying the control signal of the amplifier to produce a modified control signal, depending on the mode of operation; a switch for switching in at least one of the torque control circuit, the speed clamp circuit