Abstract: A vibromotor (10) includes a polysilicon surface-micromachined substrate. A movable guided element is slidably mounted on the substrate. At least one thermal actuator (20) has an impact head (40) and an anchoring end. The anchoring end pivotally disposed on the substrate external to a side of the movable guided element controls the movement of the movable guided element by electrothermally biasing the impact head (40) to tap against the movable guided element.

Abstract: A micromechanical system can include a substrate, an actuator, and an actuated element. In particular, the actuator can include a serpentine arrangement of alternating actuating and opposing segments anchored at a first end thereof to the substrate wherein the actuating segments deflect in response to actuation thereof so that a second end of the serpentine arrangement moves relative to the substrate upon deflection of the actuating segments. The actuated element is attached to the second end of the serpentine arrangement so that the actuated element moves relative to the substrate upon deflection of the actuating segments. Related methods and actuators are also discussed.

Abstract: A linear actuator includes a plurality of sub-modules disposed in adjacent array and adapted to translate reciprocally parallel to a common axis. A plurality of shape memory alloy wires extend generally linearly and parallel to the axis, and are each connected from one end of a sub-module to the opposed end of an adjacent sub-module. The SMA wires are connected in a circuit for ohmic heating that contracts the SMA wires between the sub-modules. The sub-modules are linked by the SMA wires in a serial mechanical connection that combines the constriction stroke displacement of the SMA wires in additive fashion to achieve a long output stroke. Moreover, the sub-modules are assembled in a small volume, resulting in an actuator of minimal size and maximum stroke displacement.

Abstract: A microelectromechanical (MEM) ratcheting apparatus is disclosed which includes an electrostatic or thermal actuator that drives a moveable member in the form of a ring gear, stage, or rack. Motion is effected by one or more reciprocating pawls driven by the actuator in a direction that is parallel to, in line with, or tangential to the path. The reciprocating pawls engage indexing elements (e.g. teeth or pins) on the moveable member to incrementally move the member along a curved or straight path with the ability to precisely control and determine the position of the moveable member. The MEM apparatus can be formed on a silicon substrate by conventional surface micromachining methods.

Abstract: To control a relative rotation between two elements (10, 12), such as flaps of a deployable mechanical structure, on a space vehicle, a torsion bar (16) is used made of a bistable shape memory alloy, heated over its whole length by heaters stuck on the bar and retained by hooping rings. A stop (22) restricts pivoting to the pre-set pivoting angle to be controlled. Excess pivoting of the torsion bar (16) is applied to a mechanical fuse (18), interposed between the bar and one (12) of the elements.

Abstract: An actuator device has electrical components, which are subjected to electric voltage, located inside a housing near movable mechanical elements. Insulation of the electrical components from the environment is achieved by introducing into the housing an expanding material, specifically a silicone elastomer of a type suitable to reticulate for forming a protective foam.

Abstract: A stepper motor includes the following. A rotatable hub. A first shaped memory alloy (abbreviated to SMA) rotary-driver, which when heated undergoes a shape change to rotationally couple with the hub and rotate the hub in a predetermined direction, and which can be deformed to reverse the shape change to rotationally uncouple from the hub. A first return spring connected with the first SMA rotary-driver for deforming the first SMA rotary-driver, when no longer heated, to reverse the shape change of the first SMA rotary-driver and rotationally uncouple the first SMA rotary driver from the hub. A second SMA rotary-driver, which when heated undergoes a shape change to rotationally couple with the hub and rotate the hub in the predetermined direction, and which when can be deformed to reverse the shape change to rotationally uncouple from the hub.

Abstract: Axial sections of a casing assembly such as that of a rocket are maintained interconnected by latching prongs on which thermally responsive Nitinol rings are positioned. Operational control over the latching prongs is achieved by selection of material properties and dimensions of the Nitinol rings during manufacture thereof.

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: An airfoil member, especially a rotor blade for a helicopter, includes an airfoil body and a servo-actuated flap tiltably connected to the airfoil body so as to form at least a portion of the trailing edge of the airfoil member. At least one piezoelectric actuator is arranged inside the airfoil member, and connected to the servo-flap via a transmission mechanism and a connecting rod linkage so as to tiltingly deflect the servo-flap as needed. Preferably, two counter-acting piezoelectric actuators are connected to the flap via respective transmission mechanisms and connecting rod linkages. An elongation of the piezoelectric actuators in the span width direction of the airfoil member is converted or redirected into an actuating motion in the chord length direction of the airfoil member by the transmission mechanisms.

Abstract: A heat converter engine comprising a crank shaft, an actuator assembly coupled to the crank shaft, and a heating means. The actuator assembly includes a plurality of shape memory elements that are malleable when below a critical temperature and return to their original shape when above the critical temperature. The heating means raises the temperature of a first portion of the shape memory elements above the critical temperature and a cooling means lowers the temperature of a second portion of the shape memory elements below the critical temperature. This action of heating and cooling the shape memory elements causes rotation of the crank shaft.

Abstract: A media ejection system includes a peripheral unit having a housing, an ejection mechanism, and a memory wire coupled to the ejection mechanism. The system further includes a digital processor for issuing ejection commands, and a controller responsive to the ejection command for controlling a current flow through the memory wire. When sufficient current flows through the memory wire, it contracts to activate the ejection mechanism, thereby ejecting a removable medium (such a PCMCIA card) from the housing of the peripheral unit. A method of the invention includes the steps of receiving an ejection request, issuing a ejection command in response to the ejection request, where the ejection command includes parameters for controlling current flow through the metal alloy, and electrically energizing the memory alloy in accordance with the parameters such that the memory alloy undergoes a dimensional change to activate a removable medium ejection mechanism.

Abstract: A mechanical actuator assembly is disclosed. The actuator assembly comprises an actuator body with an element moveable with respect to said body to perform a function. In general, the moveable element is in the form of a piston or a rod. The actuator assembly further comprises a mounting mechanism allowing the movement of the actuator body relative to the moving element or piston in response to preset conditions of pressure or force.

Abstract: A three-layered metallic semiconductor strip in the form of a thermocouple with self-contained heating and cooling means when an electrical current is applied thereto to cause the controlled expansion and contraction of selected layers to move the strip to accomplish work.

Abstract: MEMS (Microelectromechanical System) structures are provided that are designed to rotate in response to thermal actuation or the like. In one embodiment, the MEMS rotary structure includes a hub having one or more radial spoke members that impose a rotational force upon the hub in response to applied changes in temperature. The MEMS rotary structure can also include a ring at least partially encircling the hub and connected to the hub by means of one or more hub spoke members. Controllable clockwise, counterclockwise, or both clockwise and counterclockwise rotation of the hub or ring are provided. The MEMS rotary structures can also include thermal arched beam actuators that are operably connected to the spoke member. As the temperature changes, the thermal arched beam actuators move the spoke members in order to rotate the MEMS structure.

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 two-way variable-section control valve for a refrigeration circuit, having a movable member for choking a refrigerant passage interposed between the inlet and outlet of the valve; the position of the movable member is controlled by a wax actuator having a bulb fitted with an electric resistor supplied by a control circuit; and the bulb is immersed in and cooled rapidly by the refrigerant when the heat supplied by the resistor is reduced, thus ensuring rapid response.

Abstract: A thermally buckling linear micro structure, in which by isolating technology a thermal oxidization isolation layer are generated on the two ends of a micro structure, or a material with larger thermal inflation coefficient is deposited, or the area of thermal conduction is reduced so that the two ends of a micro structure has a larger thermal stress and the membrane structure may be heated uniformly so to cause a thermally buckling deformation, therefore, the deformation of the membrane type micro structure is amplified linearly with the input power. This micro structure is formed as a membrane type by a membrane manufacturing technology.

Abstract: An improved form of thermal actuator suitable for use in a MEMS device. The actuator includes a first material such as polytetrafluoroethylene having a high coefficient of thermal expansion and a serpentine heater material having a lower coefficient of thermal expansion in thermal contact with the first material and heating the first material on demand. The serpentine heater material is elongated upon heating so as to accommodate the expansion of the first material.

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 micromechanical actuator having the ability to move in two directions. The actuator can be manufactured in planar arrays using semiconductor manufacturing equipment. The planar array of actuators can be used as a microcillia array.The actuators are formed from two layers of electrically resistive material which are used to heat a non-conductive material which has a high coefficient of thermal expansion. The pattern of resistive material in the two layers is arranged such that the actuator can be bent in two directions, both in the plane of the actuator and normal to the plane of the actuator.

Abstract: A mesh of quantum wires is utilized in a non-conductive material to improve its conductivity. The non-conductive material can be highly expansive interposed in the mesh. The expansive material is ideally polytetrafluoroethylene which has a high coefficient of thermal expansion and the wires can comprise carbon nanotubes.

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: An actuator for at least translationally or linearly moving an object from a first position to a second position displaced from the first position is disclosed. In one embodiment, the actuator includes a strip of shape memory alloy configured as a coil wound about a first rotatably-fixed member, the strip having first and second end portions, the first end portion being interconnectable to the first rotatably-fixed member and the second end portion being operatively associated and/or interconnectable with the object to be moved, and a heating assembly adapted to heat at least a portion of the strip of shape memory alloy from a first temperature corresponding to the strip being in a martensitic state to a second temperature corresponding to the strip being in an austenitic state, the second temperature being above a martensitic/austenitic transformation temperature of the shape memory alloy.

Abstract: A joint assembly having a plurality of concatenated joints, each actuated by a negative coefficient of expansion material such Ti Ni, is capable of performing highly dexterous maneuvers in three dimensions without built in torsional stiffness. The Ti Ni actuators are coiled around the body of opposing joint halves and are capable of maximizing large angular motion while making the joint dimensions as compact as possible. The actuators also operate with low current and thereby minimize heat dissipation.

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: A fluid flow regulating valve using a thermal expansion material. The valve includes a body provided with inlet and outlet ports; a displacement control part in the body, the displacement control part containing the thermal expansion material and displaced toward the outlet port when the thermal expansion material expands, thereby regulating a degree of opening of the outlet port; and a heater for heating the thermal expansion material within the displacement control part. The displacement control part includes a container containing the thermal expansion material, the container being coupled to the body and an expansion plate for regulating the degree of opening of the outlet port by being expanded in accordance with an expansion of the thermal expansion material, the expansion plate being hermetically coupled to the container.

Abstract: A rotary actuator includes a bar made of shape memory alloy having ends provided with thermally insulating interface elements for interfacing with elements that are to be rotated relative to each other. An electric heater surrounds the bar and is apt to heat it above its transition temperature to the austenitic domain. The actuator is suitable for deploying or rotating solar panels.

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: A thermostatic control valve has an expansion composition held in a cavity thereof. The composition contains electrical conductor particles dispersed throughout an electrical isolator. The particles conduct electrical current through the isolator when the electrical isolator has a volumetric size that is less than a predetermined expanded volume. When the isolator expands to the predetermined expanded volume, the distance between the particles is increased to the extend that the electrical current cannot be conducted.

Abstract: A tri-clad metallic semiconductor strip with self-contained heating and cooling to cause the controlled expansion and contraction thereof to more the strip to accomplish work.

Abstract: The present invention introduces two revolutionary concepts (a caterpillar and a squeeze engine) for rotary engines with features highly desirable for space applications, e.g., very high torque, light weight, low power AC or DC input, and smooth stroke over indefinite rotation. Through these unique advantages, the proposed concepts meet an existing demand in the space industry to which, so far, only very high cost and complex solutions have been developed. Although both concepts exploit the same physical phenomenon (the significant 15% volume change related to the paraffin solid-liquid phase change), their similarity stops here. They represent fundamentally different design philosophies and offer different performance characteristics. Preliminary calculations show that the caterpillar engine with no friction-prone slip contacts shall output an approximate 150 lbf--in torque for a 2 inch diameter and 0.5 inch deep cylindrical configuration while consuming approximately 20 W direct current.

Abstract: A compact fluid control valve effects a reliable fluid flow regulation by the use of a shape memory alloy wire. The valve comprises a barrel provided with a base member and a valve body. The valve body is cooperative with the base member to define therebetween a valve opening in the course of an internal flow path through the valve for a fluid. The valve body is movable towards and away from the base member to vary the valve opening for regulating the flow of the fluid. A bias spring urges the valve body for varying the valve opening in one direction. The shape memory alloy wire connects the valve body to the barrel to move the valve body against the bias spring for varying the valve opening when heated. The barrel has anchor members for securing the ends of the wire.

Abstract: A thermostatic working element has a housing in which an electric resistance heating element is arranged whose electric connecting wires are sealingly guided to the outside. The resistance heating element contains a carrier body on which a resistance layer is mounted to which the connecting wires are soldered. A base is molded to the carrier body and is sealingly arranged in the housing.

Abstract: To command notably the unclamping and the separation of two components, on a spacecraft, such as a satellite or a probe, a single actuation pushing device (10) is driven by a form memory device (36) positioned in a casing (12), between a wall (18) of the latter and a boss (24). It is linked to a heater (38). A system to prevent mistakes (20, 26, 32), sensitive to a displacement of the component (24) caused by an elongation of the device (36), prevents assembly of the pushing device (10) when it has already been actuated.

Abstract: An actuator (A) includes a body (10) in which a plurality of chambers or bores (34) are defined. The bores are interconnected at an inner end by an elongated passage (30). A heater element (32) extends along the elongated passage. The elongated passage and the inner portion of each chamber or bore are filled with a polymeric material which expands and flows on heating, preferably undergoing a solid to liquid phase change. Extensible members (12), such as pistons, diaphragms, bellows, or the like, are mounted in the bores or wells. When the heater heats the polymeric material causing it to expand and flow, the extensible elements (12) extend under high force with limited travel. In one embodiment, the extension of the extensible members moves a thrust bearing (B) causing frictionally engageable plates (18, 22) of a friction member assembly (C) to engage.

Abstract: An actuator develops a displacement from a force; the actuator employs active tension elements which comprise a fiber or fibers which shorten under activation, for example, shape memory alloy fibers; the fiber or fibers are entrained between opposed, spaced apart support members, typically a stack of spaced apart disks; the entrained fiber or fibers define a cage of crossing lengths of fiber in symmetrical array, typically a helicoidal array. Activation of the fibers shortens the fiber lengths producing a relative displacement of the support members which can be translated to a component which is to be displaced, and to which the actuator is operably connected, in another embodiment the active tension elements stretch under stress so that instead of an actuator there is formed a shock absorber which eliminates displacement with a force.

Abstract: A housing (10, 46, 64, 90, 100) has an internal opening in which a thin recess is defined for receiving a heat expansible polymer (30) and a heating element (24). In some embodiments, an insert (14, 98, 102) is inserted into the housing bore such that the thin recess is defined therebetween. In other embodiments, the recess is defined between the housing and a force receiving surface of a piston (40, 60). When the heating element is heated, the polymer expands, forcing the piston to extend. When heating is stopped, the polymer cools allowing the piston to retract. In the embodiment of FIG. 4, the retraction is accelerated by a second polymer and heating element region (54). In other embodiments, a transmission arrangement (72, 74, 78; 124, 126, 128) is provided for converting the relatively high force, low travel of the heated polymer to a higher travel lower force output.

Abstract: An operator selects an operating characteristic, such as a degree of extension or force of an extension member (66) of a thermal actuator (16), with an input circuit (10). The input control circuit generates a reference signal. A feedback circuit (18) monitors a characteristic of the thermal actuator such as a temperature of its internal polymer, extension of the extension member, force, or the like, and generates a corresponding feedback signal. An error circuit (12) compares the reference and feedback signals and generates an error signal in accordance therewith. A dither circuit (30) generates an oscillating dither signal that is superimposed on one of the control and feedback signals before comparison by the error circuit. A power conversion circuit (14) adjusts an amount of electrical power supplied to a heating element (54) of the thermal actuator in accordance with the error signal.

Abstract: An electro-thermal actuator has linear displacement of its actuator rod accurately controlled and monitored. The actuator includes a sealed chamber containing an expansible and contractible working fluid. The working fluid is heated by way of pulse width modulated current applied to a heater in thermal contact with the fluid. As heat is applied to the working fluid, it undergoes a phase change to a gas. The resulting gas increases the pressure within the chamber, thereby exerting force on a piston and linearly displacing an actuator rod attached to the piston against the bias of a spring. The actuator includes a temperature sensor mounted within the chamber and in thermal contact with the working fluid to thereby monitor the temperature of the working fluid. The working fluid temperature is provided as an input to a feedback circuit which controls the width of the current pulses applied to the heater used to heat the working fluid.

Abstract: A piezoelectric actuator includes a plurality of linearly axially expandable hard piezoelectric rods located between two plates and are distributed about a central twistable core fastened between the plates, with the axis of the rod skew to the axis of the core, resembling a squirrel cage. The actuator produces a twisting movement between the plates, responsive to voltage induced expansion of those piezoelectric rods. Fly by Wire aircraft control is realized with the actuator in various systems providing all electric control of aerodynamic surfaces, including an electronic helicopter swashplate by which the effective pitch of the main rotor blade is controlled.

Abstract: A pump utilizing a shape memory alloy member which is connected to electric terminals to be contracted by the supply of electric power for lowering a piston, the piston mounted to slidably move within a cylinder to thereby introduce a fluid into the cylinder is raised by a biasing force of a bias spring to externally discharge the fluid introduced in the cylinder. The pump has a simple structure which is light and easily repaired and maintained.

Abstract: A tri-strip memory metal actuator is disclosed using first and second oppositely arcuate strips of electrically conductive or semiconductive memory metal, each bound respectively to opposite sides of a straight central strip of electrically conductive material to form, when current is applied therethrough, a Peltier junction causing one of the arcuate strips to heat and return to its memory metal state while the other of the arcuate strips cools and bends along with the central strip to the arcuate shape of the heated strip which bending is reversible when current is applied in the opposite direction and which actuator, if no current is applied, is maintained in the straight position of the central strip.

Abstract: A casing (11, 12) holds an actuator (18) having a stem (21) that is moves a plunger with substantial force in response to the actuator (18) being heated. The movement of the plunger (22) loads a compression spring (23) that is located between a base end of the plunger (22) and an opposing end wall of the casing. Two longitudinal casing sections (11, 12) form arcuate projections (43, 44) on the opposing end wall (49) which are inserted within at least one coil of the spring with an interference fit to hold the casing half sections together. Beams (64, 65, 74, 75) adjacent the base end wall (17) add support against the thrust reaction movement of the actuator housing (18) in response to movement of the plunger (22) against the compression spring (23).

Abstract: A microactuator preferably in the form of a microminiature valve for controlling the flow of a fluid carried by a flow channel includes a first substrate having a thermally-actuated member selectively operated by a thermal actuator such that the first substrate thereby develops thermal energy, and a second substrate having opposed first and second major surfaces. The second substrate is attached to the first substrate at the first major surface. The second major surface defines an isolation cell for enclosing a volume when the second substrate is attached to the support to thereby reduce the thermal mass of the microactuator and to thermally isolate the first substrate from the support.

Abstract: A heat sink (14) provides thermal communication between an actuator (18) and fluid controlled by a valve (12) which is flowing through a conduit (10). The actuator includes a vessel which is defined on its largest surfaces by plates (22, 50) of beryllium oxide thermally conductive ceramic covered with thermally conductive, relatively electrically non-conductive nichrome foil (24, 26). Longitudinal sides (30, 32) of the vessel are also relatively non-conductive. A thermally and electrically conductive core, such as accordion pleated beryllium copper foil (44) or a carbon fiber mat (82, 116) is disposed in the chamber. Electrical current flows through the core itself (FIG. 4) or through electrically insulated heating wires (80) (FIG. 5) or through an electrically insulated heating surface layer (FIG. 6) causing resistance heating and melting of a non-gaseous polymeric phase change compound (46). The resistance heating current is inductively induced in the embodiment of FIG. 8.

Abstract: An electrothermal actuator includes a housing containing a working fluid and a heater disposed in the fluid within the housing. A piston is slidably disposed in the housing for movement in response to heating and cooling of the working fluid. An output member is coupled to the piston and movable between first and second positions for transmitting a drive force from the piston to a load. A latch mechanism is operatively connected to the output member for releasably latching the output member in the second position without continuously heating the working fluid. The latch mechanism includes a coil and a magnetic member that releases the latch in response to a force produced by a magnetic field generated when a current flows through the coil. The output member can move linearly or rotationally.

Abstract: Rotary actuators and other mechanical devices incorporating shape memory alloys are provided herein. Shape memory alloys are a group of metals which when deformed at temperatures below their martensite temperatures, resume the shapes which they had prior to the deformation if they are heated to temperatures above their austensite temperatures. Actuators in which shape memory alloys are employed include bias spring types, in which springs deform the shape memory alloy (SMA), and differential actuators, which use two SMA members mechanically connected in series. Another type uses concentric cylindrical members. One member is in the form of a sleeve surrounding a cylinder, both being constructed of shape memory alloys. Herein two capstans are mounted on a shaft which is supported in a framework. Each capstan is capable of rotating the shaft. Shape memory wire, as two separate lengths of wire, is wrapped around each capstan to form a winding around that capstan.

Abstract: A valve construction and method of assembling the same are provided, the valve construction having a deflector unit for directing fluid flow from the inlet of the housing means of the valve construction away from an operating part of a bimetallic lever means of the valve construction that controls a valve seat means thereof, the deflector unit having a part engaging one of a top and bottom edge of a screen at the inlet of the housing means so as to hold another part of the deflector unit in a cantilevered manner in the internal chamber of the housing.

Abstract: A micro-actuator includes force elements and compensation elements arranged on a bending element such that a change in the environmental temperature does not cause any flexing of the bending element.