Abstract: A thermo-magnetic actuator includes operative components, preferably in a sealed container, from which a rotatable or translatable shaft extends. The shaft is driven by supplying electrical power to a heater in a closed chamber containing a working fluid that expands upon being heated. The expansion of the fluid drives a piston that, in turn, slides a rack coupled to the shaft. A ferromagnetic target is connected to the rack and attracted by a magnetic field produced by an electromagnet that receives electrical power from the same source as the heater. The attraction of the target causes an end of the target to latch magnetically and mechanically and to open an electrical switch, disconnecting current flow to the heater, without disturbing current flow to the electromagnet. The target is released and the rack and target return to their original positions upon termination of current flow to the electromagnet.

Abstract: A motor-driven actuator extends and retracts a piston rod. The actuator includes a housing, an electric motor having a motor shaft, a piston rod slidably extendable and retractable with respect to the housing, a speed-reduction stage coupled to the motor shaft and rotating a drive shaft parallel to the motor shaft, a speed and direction-change stage coupled to and driven by the drive shaft and rotating a wheel gear substantially perpendicular to the motor shaft, and a driving stage coupled to and driven by the wheel gear and extending and retracting the piston rod relative to the housing along a direction parallel to the motor shaft. The actuator also includes a position detector detecting when the piston rod is in the extended and retracted positions. Preferably, the position detector includes Hall effect sensors and a permanent magnet mounted on a piston driving the piston rod.

Abstract: A thermo-magnetic actuator includes a housing; a chamber within the housing; a working fluid changing phase upon heating and located in the chamber; an electrical heater disposed within the chamber for heating the working fluid; a piston rod slidably disposed in the housing and movable between retracted and extended positions; a spring biasing the piston rod toward the retracted position; an electromagnet disposed at an end of the housing and generating a magnetic field; and a ferromagnetic target assembly attached to the piston rod, sliding within the housing, and attracted toward the electromagnet to maintain the piston rod in the extended position even if electrical power is no longer applied to the heater. Preferably, the position of the piston rod is detected by the actuator and electrical current flow to the electrical heater is terminated when the piston rod is detected at the extended position.

Abstract: 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.

Abstract: 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.

Abstract: A motor-driven actuator extends and retracts a piston rod. The actuator includes a housing, an electric motor having a motor shaft, a piston rod slidably extendable and retractable with respect to the housing, a speed-reduction stage coupled to the motor shaft and rotating a drive shaft parallel to the motor shaft, a speed and direction-change stage coupled to and driven by the drive shaft and rotating a wheel gear substantially perpendicular to the motor shaft, and a driving stage coupled to and driven by the wheel gear and extending and retracting the piston rod relative to the housing along a direction parallel to the motor shaft. The actuator also includes a position detector detecting when the piston rod is in the extended and retracted positions. Preferably, the position detector includes Hall effect sensors and a permanent magnet mounted on a piston driving the piston rod.

Abstract: A thermo-magnetic actuator includes a housing; a chamber within the housing; a working fluid changing phase upon heating and located in the chamber; an electrical heater disposed within the chamber for heating the working fluid upon application of electrical power to the electrical heater; a piston rod slidably disposed in the housing and movable between a retracted position, retracted with respect to the housing, and an extended position extending substantially outward of the housing, the piston rod being driven and sliding from the retracted position to the extended position in response to heating of the working fluid by the electrical heater; a spring biasing the piston rod toward the retracted position; an electromagnet disposed at an end of the housing and generating a magnetic field when an electric current is supplied to the electromagnet; and a ferromagnetic target assembly attached to the piston rod, sliding within the housing, and attracted toward the electromagnet, when an electrical current flows

Abstract: A compact electrothermal actuator includes a housing having a longitudinal axis. A slot extends through the housing. 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 guide pin extending transverse to the longitudinal axis and protruding into the slot. The slot may be linear or helical for sliding of the piston between the first and second positions without or with rotation of the piston. The length of the actuator, measured along the longitudinal axis, is constant, independent of the position of the piston within the housing.

Abstract: A method of making an elastomeric diaphragm includes preparing a mixture of an elastomer containing dispersed fibers; heating the mixture so that the mixture flows under pressure; injecting the mixture into a mold having a cavity in the configuration of a diaphragm with a central axis of symmetry, so that the mixture flows into the mold along the central axis of symmetry of the diaphragm and, within the mold, parallel to the central axis of symmetry, until the mold is filled, with the fibers substantially oriented to lie within planes including the central axis of symmetry; at least partially curing the diaphragm; opening the mold; and removing the diaphragm from the mold. An elastomeric diaphragm has a central axis of symmetry and includes an elastomeric body with reinforcing fibers dispersed throughout the elastomeric body, the fibers being oriented to lie within planes including the central axis of symmetry.