Abstract: An apparatus and method for converting waste heat from a low temperature heat source, such as an electrical component, to work energy and for efficiently transferring unconverted or remaining waste heat away from the heat source. The apparatus includes a chamber having a first location adapted to receive heat from the heat source, and a second location adapted to dissipate heat transferred via an acoustic wave in the chamber. The acoustic wave may be produced by a first vibration member coupled to an interior surface of the chamber and disposed at an end of the chamber, where the first vibration member is adapted to vibrate at a resonant frequency of the chamber. Alternatively, a first and a second vibration member that are both adapted to vibrate at the resonant frequency of the chamber may be disposed equidistant from opposing ends of the chamber to produce a standing acoustic wave within the chamber.

Abstract: An over-current and thermal protection device adaptable for use as an electrical interrupt and in a battery environment. The protection device has a pair electrical conductors, an electrically conductive resilient switch member engageable in contact with the conductors to define an electrical conductivity pathway. The switch member is actuated by a thermally responsive shape memory alloy strip and activatable in response to a change in temperature at a predetermined level to effect a change in the metallurgical state of the shape memory alloy and position of the engagement of the switch member with one of the conductors.

Abstract: Split spool release apparatus for retaining and deploying a deployable appendage. Exemplary apparatus comprises a housing which houses a split spool clamping device, a release nut attached to the deployable appendage, a locking mechanism or fuse assembly, and an actuator. The split spool clamping device comprises a plurality of separable sections that secure the release nut and deployable appendage using the restraining wire that is wrapped around them. In one embodiment, the split spool clamping device may comprises a threaded split-nut. The restraining wire is preferably wrapped using variable pretension, having low tension at the fuse end and higher tension at the nut end (load application end). The fuse assembly is coupled to the restraining wire at a location that is distal from the deployable appendage, and is activated by the actuator to release the restraining wire.

Abstract: The present invention provides actuators and actuator devices that take advantage of a strain gradient variation of an actuator element between a first phase and a second phase. The actuator elements can be positioned in any type of shape. For instance, the actuator element in the first phase can be any type of curved, non-linear or irregular shape as long as a strain gradient along a cross-section of the actuator element can be established. The actuator element in the second phase is positioned in a different shape when compared to the first phase as long as it is in a direction to minimize the strain gradient. Different actions can be generated such as a rotary movement, a linear movement, an expanding movement, or a combined linear and rotary movement. The actuator element could also be configured to generate a linear movement by combining contraction and strain gradient variation.

Abstract: The present invention provides a bistable switch using a shape memory alloy, and a method for manufacturing the same. More specifically, the bistable switch includes a substrate having at least one power source; a flexible sheet having a first distal end attached to the substrate; a bridge contact formed at a second and opposite distal end of the flexible sheet; and at least one heat activated element connected to a first surface of the flexible sheet and between the second distal end and the power source. During operation, current from the power source passing through the heat activated element to indirectly bend the flexible sheet and short the signal contacts on the substrate with a sustainable force.

Abstract: The present invention discloses devices and a method of fabrication of devices using a shape memory effect, thin film with a compositional gradient through the thickness of the film. Specifically, a NiTi SME thin film is disclosed that can be used in actuators, MEMS devices and flow control. The process of fabrication includes a gradual heating of the target over time during the sputter deposition of a thin film on a substrate under high vacuum, without compositional modification. The resulting thin film exhibits two-way shape memory effect that can be cyclically applied without an external bias force.

Abstract: A lock assembly is described for a personal computer. The assembly comprises a lock member movable between a locked position and an unlocked position and a shape memory wire arranged to move the lock member between the lock position and the unlocked position in response to one or more electrical signals that generate currents therein.

Abstract: A thermal switch assembly includes a dielectric spacer and a switch blade member of shape memory metal sandwiched between a pair of flat metal plates. The spacer provides a cavity between the plates and the switch blade member has a switch blade portion projecting into the cavity. The switch blade member has a mounting portion engaging one of the metal plates, and the switch blade portion normally is under bending stress in engagement with the other metal plate to provide a current path between the plates. At elevated temperatures, the switch blade portion of shape memory metal moves out of engagement with the other metal plate to interrupt the current path. Fasteners integral with the dielectric spacer cooperate with the metal plates and the switch blade member to hold the switch assembly together with the spacer and the mounting portion of the switch blade member compressively sandwiched between the metal plates.

Abstract: A thermal switch assembly has a contact member of shape memory alloy sandwiched between a pair of electrically conductive outer members. A contact arm on the contact member has a deformed shape at normal temperatures and a recovered shape at elevated temperatures. The contact arm occupies two different positions in its deformed and recovered shapes, and provides a current path between the outer members in one position while interrupting the current path in the other position.

Abstract: A temperature actuated switch having a resilient switch blade that is movable between open and closed positions and extends perpendicular to an elongated actuator of shape memory alloy. The actuator has an elongated deformed shape at normal temperatures and a contracted recovered shape at an elevated temperature. An end portion of the actuator is attached to the switch blade to provide movement of same between open and closed positions as the actuator changes between its deformed and recovered shapes.

Abstract: The present invention provides a bistable switch using a shape memory alloy, and a method for manufacturing the same. More specifically, the bistable switch includes a substrate having at least one power source; a flexible sheet having a first distal end attached to the substrate; a bridge contact formed at a second and opposite distal end of the flexible sheet; and at least one heat activated element connected to a first surface of the flexible sheet and between the second distal end and the power source. During operation, current from the power source passing through the heat activated element to indirectly bend the flexible sheet and short the signal contacts on the substrate with a sustainable force.

Abstract: A thermal switch having a current carrying switch blade actuator of shape memory metal has a resistance less than 20 milliohms and a contact force greater than 150 grams. The actuator is deformed to less than about 8% strain, and a very hard high strength dielectric material is used for a spacer.

Abstract: A process for conditioning shape memory alloys is disclosed. The process preferably includes force application/release cycling of a shape memory alloy at a temperature above the martensitic-austenitic transformation (A.sub.f) finish temperature of the alloy, but below the maximum temperature at which an austenitic-martensitic transformation will be effected by the force application. The alloy is preferably cold-worked and annealed prior to force application/release cycling. The invention yields greater control over martensitic-austenitic and austenitic-martensitic transformation temperatures and yields reduced hysteresis variability. In certain disclosed embodiments a TiNi or CuAl containing alloy may be cold-worked between about 20% and 45%, and annealed to maintain between about 3% and 8% of the cold working. The alloy may then be heated to between about A.sub.f and 5.degree. C. and A.sub.f 15.degree. C.

Abstract: A thermal switch assembly includes a dielectric spacer and a switch blade member of shape memory metal sandwiched between a pair of flat metal plates. The spacer provides a cavity between the plates, and the switch blade member has a switch blade portion projecting into the cavity. The switch blade member has a mounting portion engaging one of the metal plates, and the switch blade portion normally is under bending stress in engagement with the other metal plate to provide a current path between the plates. At elevated temperatures, the switch blade portion of shape memory metal moves out of engagement with the other metal plate to interrupt the current path. Fasteners integral with the dielectric spacer cooperate with the metal plates and the switch blade member to hold the switch assembly together with the spacer and the mounting portion of the switch blade member compressively sandwiched between the metal plates.

Abstract: A novel shape memory alloy electrical switch is disclosed, including both momentary and especially a latching relay. The switch/relay disclosed is particularly useful in low power control of appliances, including i.a. refrigerators. Used with a microprocessor, microcontroller, or like device to control the shape memory alloy switch/relay, an adaptive control routine may be included which facilitates an especially low-power dissipation, highly effective appliance control module, especially suitable for refrigerators. The disclosed refrigerator control module can be manufactured at low cost with high reliability.

Abstract: A distributed activation system for a unitary sheet of electrically conductive or insulative shape memory alloy having a sufficiently small section to limit the lateral flow of heat including at least one heating element disposed on the shape memory alloy sheet for locally heating an adjacent portion of the sheet such that the adjacent portion assumes a predetermined shape when activated to its threshold temperature. The activation system may be configured for shape memory alloy apparatus and related methods in combination with a control system for selectively activating discrete shape memory alloy portions with various combinations of at least one heating element that receive an adjustable current such that the resultant local heating causes the sheet to assume a desired overall shape. Methods of forming and selectively activating two-dimensional sheets of electrically conducive and insulative shape memory alloy are further provided.

Abstract: A highly reliable release apparatus which is used to stow or release desired devices such as, for example, solar arrays, antenna positioning mechanisms, reflectors, found on satellites, space stations or spacecraft. Deployment of the desired device is prevented or allowed by respectively restraining or releasing a first member under tension. The apparatus comprises a support member having an opening and a first face arranged about the opening. A second member is located within the opening when the first member is in tension and is adapted to be attached to an end of the first member. At least three locking members such as fuse wires are arranged on the first face of said support member for restraining the second member within the opening in order to maintain tension on the first member. The second member is attached to the first member in a manner such that at least two of the fuse wires must be severed before the restraint on the second member is released.

Abstract: An actuation device comprising:at least two thermal actuators (5A,5B) electrically supplied, each thermal actuator (5A,5B) comprising relevant thrust means (4A,6A,4B,6B) being movable to perform a predetermined stroke;at least a working means (12) moved by means of said thermal actuators (5A,5B) and connected with the thrust means (4B,6B) of one of said thermal actuators (5A,5B);where said working means (12;12A;18) is able to take at least three different steady working positions (I,II,III) in function of the presence of supply to a first (5B) or a second (5A) or both said thermal actuators (5A,5B).According to the invention, said first thermal actuator (5B) is free to move with respect to said second thermal actuator (5A) and means (6A,11) are provided for transferring the thrust produced by the second thermal actuator (5A) to the first thermal actuator (5B), and causing a change in the reciprocal positioning of one thermal actuator with respect to the other.

Abstract: A switch has a switching mechanism, which switches at a response temperature, for opening and closing a circuit that can be connected to external terminals of the switch. In this context, the switching mechanism has a movable contact, electrically connected to one external terminal, which as a function of the temperature of a bimetallic part is in contact with a fixed contact that is electrically connected to the other external terminal. The switching mechanism further has a safety element that changes its shape into a high-temperature shape if its temperature reaches a transformation temperature which is above the response temperature. The movable contact is in contact with the fixed contact as a function of the temperature of the safety element.

Abstract: A self-contained unitary thermal cutoff switch assembly having a hollow sealed switch housing formed by a collector and a lid that serve as the switch contacts. Separating the collector and the lid is a plastic insulating liner that generally follows the inside contour of the collector. The lid is held in place at the open end of the collector by folding over the top lip of the collector which will, at the same time, fold over the insulator in a U-shape about the edge of the lid and hold and insulate the lid in a spaced relationship with the collector. A shape memory collector formed as a straight piece of wire is located between the lid and the side of the collector opposite the lid. The wire is held in alignment by an opening through the insulator which supports an end portion of the wire adjacent to the bottom of the collector.

Abstract: A thermal switch assembly has a stiffener disc positioned against a support flange that extends inwardly from a peripheral wall of a plastic assembly grommet. An actuator member of shape memory metal is received in a recess in the stiffener disc, and an insulator ring lies against the disc and actuator member on the opposite side of the disc from the support flange. A cap member is positioned against the insulator on the opposite side thereof from the stiffener disc, and a resilient actuator blade on the actuator member extends through a central opening in the insulator into engagement with the cap member. The actuator blade normally completes a circuit between the stiffener disc and the cap member, and automatically disengages from the cap member at an elevated transition temperature to open the circuit.

Abstract: A novel shape memory alloy electrical switch is disclosed, including both momentary and especially a latching relay. The switch/relay disclosed is particularly useful in low power control of appliances, including i.a. refrigerators. Used with a microprocessor, microcontroller, or like device to control the shape memory alloy switch/relay, an adaptive control routine may be included which facilitates an especially low-power dissipation, highly effective appliance control module, especially suitable for refrigerators. The disclosed refrigerator control module can be manufactured at low cost with high reliability.

Abstract: A thermal switch assembly has a contact member of shape memory alloy sandwiched between a pair of electrically conductive outer members. A contact arm on the contact member has a deformed shape at normal temperatures and a recovered shape at elevated temperatures. The contact arm occupies two different positions in its deformed and recovered shapes, and provides a current path between the outer members in one position while interrupting the current path in the other position.

Abstract: A novel shape memory alloy electrical switch is disclosed, including both momentary and especially a latching relay. The switch/relay disclosed is particularly useful in low power control of appliances, including i.a. refrigerators. Used with a microprocessor, microcontroller, or like device to control the shape memory alloy switch/relay, an adaptive control routine may be included which facilitates an especially low-power dissipation, highly effective appliance control module, especially suitable for refrigerators. The disclosed refrigerator control module can be manufactured at low cost with high reliability.

Abstract: A thermal switch assembly has a stiffener disc positioned against a support flange that extends inwardly from a peripheral wall of a plastic assembly grommet. An actuator member of shape memory metal is received in a recess in the stiffener disc, and an insulator ring lies against the disc and actuator member on the opposite side of the disc from the support flange. A cap member is positioned against the insulator on the opposite side thereof from the stiffener disc, and a resilient actuator blade on the actuator member extends through a central opening in the insulator into engagement with the cap member. The actuator blade normally completes a circuit between the stiffener disc and the cap member, and automatically disengages from the cap member at an elevated transition temperature to open the circuit.

Abstract: A novel shape memory alloy electrical switch is disclosed, including both momentary and especially a latching relay. The switch/relay disclosed is particularly useful in low power control of appliances, including i.a. refrigerators. Used with a microprocessor, microcontroller, or like device to control the shape memory alloy switch/relay, an adaptive control routine may be included which facilitates an especially low-power dissipation, highly effective appliance control module, especially suitable for refrigerators. The disclosed refrigerator control module can be manufactured at low cost with high reliability.

Abstract: A thermal switch having a current carrying switch blade actuator of shape memory metal has a resistance less than 20 milliohms. The actuator is deformed to less than about 8% strain, and a very hard high strength dielectric material is used for a spacer.

Abstract: A switch (10) is provided that has a housing (12), an actuator (20), a contact blade (18), first and second shape-memory wires (28,30), and first and second contact points (70,71). The actuator (20) has a first end portion (52) pivotally coupled to the housing (12), and a second end portion (22) with first and second generally opposed arm portions (24), (26) extending therefrom. The contact blade (18) has the first contact point (70) positioned thereon, and is coupled to and moveable with the actuator (20). The first and second shape-memory wires (28,30) respectively extend between the first and second arm portions (24,26) of the actuator (20) and the housing (12). The second contact point (71) is coupled to the housing (12) and is electrically engageable with the first contact point (70) in response to movement of the actuator (20).

Abstract: An actuator that uses electrothermal energy to switch between a first latching position and a second latching position. The actuator contains a leaf spring capable of latching into two distinct positions and two shape-memory wires. The shape-memory wires contract when heated and direct the leaf spring toward the two latching states. Once positioned in a latching state, the leaf spring will remain latched in that position until directed toward a different latching state by one of the shape-memory wires.

Abstract: An electrical apparatus comprising first and second PTC elements composed of a polymer composition with conductive particles dispersed therein, an insulating body, and first and second conductive terminals. Flexible conductive members having a first end that can be electrically connected to a source of electrical power and a second end that is adapted to receive and make electrical contact with the apparatus are provided. The PTC element and the insulating body are positioned between the first and second conductive terminals so that when the apparatus is inserted between the flexible conductive members, the members exert a pressure on the insulating body.

Abstract: Low voltage current limiting fuses wherein the conventional fusible element is replaced. The fuses of the invention are resettable manually or automatically such that the fuse need not be physically replaced following a fault current or overload current occurrence in the external circuit in which the fuse is incorporated.

Abstract: A thermal switch assembly includes a dielectric spacer and a switch blade member of shape memory metal sandwiched between a pair of flat metal plates. The spacer provides a cavity between the plates, and the switch blade member has a switch blade portion projecting into the cavity. The switch blade member has a mounting portion engaging one of the metal plates, and the switch blade portion normally is under bending stress in engagement with the other metal plate to provide a current path between the plates. At elevated temperatures, the switch blade portion of shape memory metal moves out of engagement with the other metal plate to interrupt the current path. Fasteners integral with the dielectric spacer cooperate with the metal plates and the switch blade member to hold the switch assembly together with the spacer and the mounting portion of the switch blade member compressively sandwiched between the metal plates.

Abstract: A time-delay switch responsive to a sensor 36 having a temperature compensation feature including bimetallic creep-type strip elements (10, 11). Additionally, the switch has an alarm function (A) with a manual reset button (9).

Abstract: A micro-dimensioned shape memory alloy composite composed of a thin film of shape memory material and a substrate film. The substrate film does not require further processing and thus the composite can be used as a switch without removing any portion of the substrate on which the SMA is deposited. It is also shown that more effective switches can be manufactured by including as a component of the composite a stress compensating film.

Abstract: An electrical apparatus comprising first and second PTC elements composed of a polymer composition with conductive particles dispersed therein, an insulating body, and first and second conductive terminals. Flexible conductive members having a first end that can be electrically connected to a source of electrical power and a second end that is adapted to receive and make electrical contact with the apparatus are provided. The PTC element and the insulating body are positioned between the first and second conductive terminals so that when the apparatus is inserted between the flexible conductive members, the members exert a pressure on the insulating body.

Abstract: A system for registering a malfunction in telecommunications equipment comprises a protective device including a terminal connector pin and a ground pin connected to ground. The system also includes a housing member for housing the protective device, the housing member including a conductive member attached thereto. A main failsafe switch connects the terminal connector pin to ground through the ground pin in the event of an overvoltage, while an alarm switch connects the conductive member attached to the housing member to ground in the event of the overvoltage. An overvoltage sensitive member contacts both the main failsafe switch and the alarm switch, and retracts both the main failsafe switch and the alarm switch while in a normal operating state of the telecommunications equipment. The overvoltage sensitive member releases both switches in the event of the overvoltage.

Abstract: A release mechanism employing an actuating element of a shape memory alloy material. When the actuating element is heated through its phase-change transition temperature it applies a force which moves a latch to a position which activates the higher energy stored in a drive spring for moving a retaining element out of engagement with a structure. A detent when in a captured position releasably holds the retaining element in its locked position, and the detent is moved from a captured position to a retracted position to release the retaining element when the latch is moved by the actuating element.

Abstract: An actuation system for the control of multiple shape memory alloy elements is achieved by arranging the shape memory actuators into a matrix comprised of rows and columns which results in approximate a fifty percent reduction in the number of electrical connecting wires. This method of actuation provides the scope for resistance measurements of the shape memory alloy actuators and therefore feedback control of the actuators can be accomplished without additional wires.

Abstract: A controller (24) is provided to selectively release an initiator (12) having first and second members (14,16) that clampingly engage an object (18) preventing it from moving in an urged direction. A spring wire coil (20) holds the members (14,16) tightly about the object, one coil end affixed to one of the members and the other coil end is held by a pair of link wire loops (82,86) of the controller (24) which is also removably secured to one of the members (14,16) by a bolt (36). When it is desired to release the object (18) an electric current is passed through the link wire loops (82,86) of sufficient magnitude to cause the loops to break, releasing the coil (20) to unwind and, in turn, release the object for urged movement.

Abstract: A T-shaped member is pivotally mounted to a support plate, and has first and second shape memory wires attached at first ends thereof to opposing portions of the T-shape. Second opposing free ends of the shape memory wires are secured to the support plate. Electrical current is conducted alternately through the first and second shape memory wires to cause the wires to contract in alternating tandem, to thereby cause the T-shaped member to move between first and second positions. Pivotal movement of the T-shaped member can be used to actuate and/or reactivate a switch device.

Abstract: An actuator device varies its functional condition from a state of rest to a working state, both stable and has a body receiving a thermal actuator, an electric heater, electric contacting elements and a transmission shaft for the thrust generated by the actuator. A bistable kinematic mechanism uses inclined planes and/or cams.

Abstract: A device for operating a side airbag is capable of rapidly deploying the side airbag and utilizing a physical collision force without an ECU. The device comprises a U-shaped beam deformed in the event of a crash to generate heat, a plurality of pairs of plate springs fixed along an inner base surface of the U-shaped beam at a predetermined interval, a thin metal plate fixed on the ends of each of the pairs of plate springs, a shape memory alloy member being capable of bending the pair of plate springs against resilient force thereof at a transformation temperature, and connecting the pair of plate springs, a contact electrically connected to the squib and being in contact with the thin metal plate by the deformation of the shape memory alloy member, and a temperature holding portion for constantly keeping the temperature of the U-shaped beam lower than the transformation temperature of the shape memory alloy member.

Abstract: A microactuator and method of operation is disclosed for use in actuating valves, electrical contacts, light beams, sensors and other elements between different actuation modes. An actuator member comprised of a shape memory alloy layer is mounted on an elastic substrate, and the proximal end of the actuator member is carried by a base. The shape memory alloy material is heated through its phase change transition temperature so that it deforms by changing volume to bend the distal end of the actuator member in a first direction relative to the base. Stress forces in the substrate oppose the bending movement, and when the shape change layer is cooled below the transition temperature the stress forces move the distal in a second direction which returns the shape change layer to its low temperature shape. Electrostatic forces are selectively applied between the actuator member and base for clamping the actuator member in one of its positions.

Abstract: A slider lifter for a disc drive is disclosed which utilizes a shape memory element to lift a slider away from the surface of a disc. The slider is supported adjacent the surface of the disc by a flexure which has a lifting wire attached thereto. The lift wire extends past the edge of the rotating disc through a hole in a leaf spring cantilevered adjacent the disc's edge and terminates in a crimped portion or stopper. The stopper is separated from the rear surface of the leaf spring by an unload space. A shape memory metal wire is attached to the leaf spring at a point spaced apart from the lift wire and extends back to a fixed support wall. Energization of the shape memory wire causes a phase change in the shape memory wire which restores the wire to its original length. The shortening of the shape memory wire pulls the leaf spring across the unload space so as to pick up the crimped portion of the lift wire.

Abstract: An over-current/over-temperature protection device (1) which includes first and second electrical contacts (2,3), a separable resistance electrical current path (4) extending between the contacts, a breaker (6) and a heater. The heater comprises the separable path (4). The breaker breaks an electrical connection between at least one of the contacts and the separable path when current above a threshold value passes through the separable path and/or the over-current/over-temperature protection device reaches a threshold temperature. The breaker (6) includes a member of a shape memory alloy which changes shape from a first configuration to a second configuration when the member is heated from a first temperature T.sub.1 to a second temperature T.sub.2. The heater heats the member from the first temperature T.sub.1 to the second temperature T.sub.2 so that the member changes from the first configuration to the second configuration.

Abstract: The present invention provides several embodiments of an electrical switch that uses a shape memory alloy (SMA). In one embodiment the electrical switch is an on-off switch and comprises a first support member with a first electrical contact mounted thereon, a second support member with a second electrical contact mounted thereon, and a third support member disposed between the first and second support members. A wire element made from a shape memory alloy (SMA) is attached at either end to the third support member. A switch element made of an electrically-conducting material is attached to the SMA wire element at a position intermediate the ends of the wire element. Heating means are provided for selectively heating sections of the SMA wire element in order to make the SMA wire element turn or rotate, thereby causing the switch element to pivot into contact with either the first electrical contact or the second electrical contact.

Abstract: An electrically-controlled actuating mechanism comprises a length of shape memory wire. A source of electrical current passes electricity through the shape memory wire and a voltage regulator controls the voltage applied to the wire. The actuating mechanism is particularly advantageous as an actuator for a model railway track switch.

Abstract: A thermally responsive switch for protecting electric motors against overcurrent and overheating conditions includes a metallic receptacle having an elongated dome-shaped portion and an opening opposite to the dome-shaped portion, a metallic header plate secured to the one end of the receptacle so as to hermetically close the opening afterwards and having a through-aperture, a thermally responsive element disposed in the receptacle in parallel with the header plate and carrying a movable contact at one end, a rod terminal secured in the aperture of the header plate by an electrically insulating material filled in the aperture for hermetic sealing so that the terminal extends through the aperture, a fixed contact support disposed in the receptacle to be perpendicular to the terminal and having an end to which a fixed contact is secured, the support being connected at the other end to the end of the terminal projected into the receptacle, by solder, and a spring for urging the support so that it is disconnected

Abstract: A circuit bypass device (30) having terminals (70, 80) is connected to contacts (70, 80) of a cell (20) to provide a conductive path (40) in response to voltage excursion therebetween. Device (30) includes: a conductive shunt (40), coupled to contacts (70, 80), that is movable from a normally non-conductive position to a conductive position between terminals (70, 80); a detector (50), coupled to conductive shunt (40), for sensing voltage excursion beyond specified limits between contacts (70, 80); and an actuator (60) having a heat-to-recover shape memory metal alloy that is formed to contract when detector (50) senses the voltage excursion, for moving conductive shunt (40) from the non-conductive position to the conductive position. The formed alloy is preferably spring-shape which contracts translationally and torsionally.

Abstract: An electric current responsive actuator has a thermally responsive force generator and an electromagnetically responsive force generator. The force generators are coupled together to produce a resultant force on a movable trip actuator. In the preferred specific embodiment of the invention, a shape-memory alloy element serves as the thermally responsive force generator.