Devices are provided for translating linear motion into rotary motion. The devices are particularly suited for use with mechanisms known as thermal motors or thermal actuators. These devices include a rotatable member, means associated with the rotatable member and adapted to be acted upon to impart a moment of rotation to the rotatable member, and means communicating between linearly driven means the motion of which is to be translated into rotary motion and means associated with the rotatable member to transmit work arising from the linear driving of the former to the latter to rotate the rotatable member. When one of these devices is utilized in combination with a thermal motor, the linearly driven member is part of the thermal motor.
A motor driven linear actuator arranged with the motor interior of the actuator plunger. The motor has affixed to its output shaft a worm gear which is engaged with corresponding teeth of an internal worm cut into the interior face of the plunger. The plunger is guided and supported during its selective reciprocation either by the motor housing or the motor housing in combination with an additional tubular housing covering the actuator.
A mechanical actuator having a housing in which a gear-nut assembly is rotatably mounted on bearings to be driven by a drive shaft extending into the housing through a sealed aperture. The gear-nut assembly includes a gear component engaging the drive shaft, a ball nut component carrying a plurality of ball members arranged in driving engagement with a screw member extending through the interior of the gear-nut assembly, and a tubular shield member mounted in covering relation about the ball nut component and sealed at the ends thereof to cover ball return tubes on the surface of the ball nut component. Annular seals are provided at each end of the gear-nut assembly to extend in sealing relation between the exterior surface thereof and the housing to thereby form a sealed cavity about the drive for the gear-nut member assembly and, preferably, the bearings thereof, and this sealed cavity is filled with lubricating oil which serves to lubricate the moving parts therein and to assist in dissipating heat generated by such moving parts.
An electrothermal actuator producing linear and/or rotational movement includes a housing having a longitudinal axis. A chamber within the housing contains a working fluid that changes phase upon heating. A piston is slidably disposed within the housing and movable along the longitudinal axis between first and second positions. A spring biases the piston toward the first position. The piston slides from the first position to the second position in response to heating of the working fluid. The piston includes a piston rod extending along the longitudinal axis and protruding from the housing. The housing includes helical grooves on an interior surface and the piston includes partially spherical recesses. Balls captured between the grooves and recesses produce rotation of the piston and piston rod when the piston moves between the first and second positions.
