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

Abstract: A portable manual muscle tester has an external actuator, a case capable of being held in one hand and a digital display indicating peak force applied to the actuator. Strain gages connected in a bridge circuit are located on a flexure contacted by the actuator. The flexure is a cantilever beam shaped to fit the small case and to prevent reflected or mounting stresses being registered in the force display. The circuit from the strain gage bridge to the display includes an instrumentation amplifier followed by a peak freeze circuit that includes operational amplifiers and a peak freeze capacitor. The peak freeze capacitor provides a voltage that is read by a digital volt meter. A further operational amplifier connected as an integrator feeds back from the peak freeze circuit to an input of the instrumentation amplifier to reset the meter to zero after the displayed force reading has been noted.

Abstract: This specification discloses a device for resetting the zero calibration of an opacity sensing meter (transmissometer) made up of a light source which may be located on one side of a smokestack, and a sensing element located on the other side of the smokestack. The rezeroing device will rezero the sensing element without using the light passing through the stack. The device samples the light at the source side of the stack by mechanically introducing an auxiliary light sensor, and generates an output from a mechanically introduced auxiliary source located on the sensor side of the stack such that excitation of the normal system sensor by the auxiliary source is the same as the excitation would be to the sensor by the normal source.