Abstract: An over-current/over-temperature protection device which includes first and second electrical contacts, a separable resistance electrical separable path extending between the contacts, a breaker means and a heater. The heater comprises the separable path. 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 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: A method of producing an integral piece of thermo-sensitive material, which is responsive to a shift in temperature from below to above a phase transformation temperature range to alter the material's condition to a shape-memory condition and move from one position to another. The method is characterized by depositing a thin film of shape-memory material, such as Nickel titanium (Ni-Ti) onto a substrate by vacuum deposition process such that the alloy exhibits an amorphous non-crystalline structure.

Abstract: An article comprises a bent strip 2, the ends (4) of which can be rotated relative to each other to cause the strip to change its shape. One embodiment of the strip is initially in the shape of a split circle. Rotation causes the strip to adopt an intermediate complex shape and then a double circle shape. One application of the invention is as a statue.

Abstract: An electromagnetic relay comprises a force transmitting member for displacing a movable contact point member as an armature moves, to come in contact with a fixed contact point member. A pressing portion of the force transmitting member which is in contact with the movable contact point member is formed of a shape memory material restoring a previously memorized shape at or above a predetermined temperature. The fixed contact point and the movable contact point are abraded resulted from the long-term use of the electromagnetic relay, thereby reducing contact pressure between the two contact points and correspondingly increasing contact resistance, so that the contact points overheats.

Abstract: A shape memory alloy consists of a three element alloy of nickel-titanium-copper which is formed as being subjected to a cold working and to a heat treatment at a temperature below recrystallization point of the alloy for storing the shape, the alloy being thereby improved in operation stability and reliability even after repetitive operation and made wider in environmental temperature range for use therein of the alloy.

Abstract: A detector array assembly which provides for the closing at operating temperature of normally open contacts between individual sensor contact mesas and readout pads of the respective detector and readout chips comprising a detector array assembly. One or more shape memory separator elements are used in conjunction with one or more biasing springs to control the spacing of the contacts. The force of the biasing spring becomes the dominant force as the apparatus is cooled down to near operating temperature, thus moving the chips closer together and establishing reliable electrical connection between the opposed sets of contacts. At temperatures near and above the normal operating temperature of 77 degrees K., the shape memory separator element provides the dominant force and drives the chips apart to open the contacts.

Abstract: An actuator such as an electrical switch which responds to an event such as a change in temperature by movement of an element between first and second positions, for example in which an electrical circuit is open and closed respectively, includes a dimensionally heat-recoverable component which, on recovery when the actuator is exposed to a high temperature, changes configuration so that a portion of the component is positioned between the element while in its first position and a support for the component, so as to restrain movement of the element towards its second position. This allows the actuator to be locked as a result of exposure to the high temperature, which can be desirable, for example, because of damage to equipment to which the actuator is connected.

Abstract: An actuator apparatus includes a plurality of actuators each having a shape-memory alloy, a power supply line unit for supplying power to the actuators, power supply control unit connected in series with at least one of the actuators, and a driving unit for driving the power supply control unit.

Abstract: A tripping device (1) for circuit breakers comprising a thermally influenceable wire-shaped tripping element (4) is presented, one end of which is attached to a rotatably supported tripping lever (3) which is under spring force and the other end of which is fixed in location. The thermally influenced lateral movement at one end of the tripping element (4) causes the unlatching of the circuit breaker. At the free end of the tripping lever (3), a locking element (11) is provided which engages a cam (10) of a contact lever (2) which is under spring force, in such a manner that the circuit breaker is switched off both with contraction and with expansion of the tripping element (4).

Abstract: A rotary actuator which provides a differential pulley pair having a shape memory alloy wire. The shape memory alloy wire is thermally cycled through its phase change transition temperature and contracts. Tension forces applied by the ends of the wires to opposite sides of the pulley pair result in a net torque which causes relative rotation between the pulley pair and a reference base. The large mechanical advantage of the differential pulley converts a large force working through a small distance into a relatively large angular rotation.

Abstract: An electromechanical relay for the activation of at least one operating circuit, has an activator (10, 110) for example in the form of a helix made of a material having form-restoring or shape memory properties. A reset element (17, 117) holds the actuator in a distorted position opposite to that of its original position as long as an electrical heating current does not flow through the actuator. When the heating current, also referred to as switching current, is passing through the actuator, the latter returns to its original position or shape against the force of the reset spring thereby activating, through an operating member, a number of contact pairs of an operating circuit.

Abstract: A circuit breaker having a fixed current contact (12,14), a movable current contact (16,18), a mechanism (20,22,54,66,68) for displacing the movable current contact (16,18) between a circuit closing position and a circuit opening position, and a latching member (32,34) disposed to cooperate with the mechanism (20,22,54,66,68) and movable in response to the magnitude of current flowing through the circuit to be controlled in order to cause the mechanism (20,22,54,66,68) to move the movable contact (16,18) in a manner to open the circuit when the magnitude of current flow exceeds a certain value, movement of the latching member (32,34) being controlled by a memory metal element (40,42) which is mechanically connected to the latching member (32,34) and electrically connected in the circuit to be heated by current flowing through the circuit to cause the latching member (32,34) to release the mechanism (20,22,54,66,68) when the current flowing through the circuit exceeds a given value for a selected period of tim

Abstract: In a bistable shape memory effect, SME, mechanism having first and second opposing shape memory effect, SME, elements (16, 20) moving an actuator (12) along a travel stroke between respective first and second positions upon heating of the respective SME element above its transition temperature mechanical frictional retainers are provided for holding the actuator at the end of its travel stroke, including after cooling of the respective SME element and return repose movement thereof. One embodiment provides a detent retainer (38, 40, 42, 44, 46). Another embodiment provides a friction wedge retainer (12a, 12b, 14a, 14b, 12c, 12d, 14c, 14d). Another embodiment provides a resiliently biased friction member (50, 52) and a lost motion coupling (56, 58) between the actuator and the SME elements.

Abstract: A thermal relay includes a housing, two fixed contacts secured to respective terminals disposed in the housing, a disc-shaped bimetal disposed in the housing and having two movable contacts made into and out of engagement with the respective fixed contacts, an adjusting screw including a screw portion and a head portion which are coupled with each other by a meltable metal, and a coil spring biasing the disc-shaped bimetal to the head portion of the adjusting screw to thereby support it.

Abstract: An active member can deform in accordance with its temperature. The active member is connected to a mechanically-operated valve member so that the operated member is driven in accordance with deformation of the active member. The temperature of the active member is adjusted to control the operated member.

Abstract: A motor controlling switch device is disclosed which comprises a casing and an operating member provided in a casing which is movable from an original position and a first operating position and from the first operating position to a second operating position. A depressing piece is disposed in one of the casings and the operating member. Sloped surfaces and holding surfaces are formed in the casing and the operating member and coact with the depressing piece, respectively, for storing the operating member to the original position when the force on the operating member is released after it has moved to the first operating position and for holding the operating member in the second operating position when the operating member is moved through the first operating position. Forward and reverse rotation switches ae provided for establishing forward and reverse motor rotation circuits when the operating member is moved to the first and second operating positions for forward and reverse rotation.

Abstract: An article in the form of a projectile, a shock-sensitive switch or a sabot having an active component of shape-memory alloy which exhibits the shape-memory effect to provide a mechanical movement in response to a pressure wave passing through the article is disclosed. A thermal enhancement component which rapidly generates heat to initiate the shape-memory effect is also disclosed.

Abstract: An apparatus for rocking a crank has a crank having opposite ends and being pivotally mounted at one end thereof to a first point on a first substrate, a first spring attached at one end thereof to a second point on a second substrate and at the other end thereof to the other end of the crank and a second spring attached at one end thereof to a third point on a third substrate and at the other end thereof to the other end of the crank, an angle defined between a line extending through the first and second points and a line extending through the first and third points, respectively, on a side opposite an arc through which said other end of the crank moves being in a range of 105.degree. to 160.degree. and the first spring or both first spring and second springs being made of shape memory alloy(s) which returns(s) to a predetermined shape upon application of heat whereby the crank is rocked back and forth by temperature variations.

Abstract: A current controlled inductor (1) having an inductor coil (4) in one state of alteration attached at one end to a displacing coil (6) in an opposite state of alteration to that of the inductor coil (4). Both coils are formed of a shape memory alloy that when heated to a predetermined temperature will return to an original configuration from an altered configuration. An electric current from a DC source (11) passing through the displacing coil (6), heats the displacing coil (6), causing the coil to contract to an original length and simultaneously pull the inductor coil (4) from its original length thereby changing the inductance effect of the inductor coil (4) on the signal source (12).

Abstract: A linear motion actuator which has a body; a member which is movable in a linear direction with respect to the body; an extended member made of shape memory alloy material, extended in a direction transverse to that linear direction so as to intersect it, supported at its ends by the body, and substantially coupled at its intermediate portion to the movable member at least with regard to mutual movement therebetween in that linear direction; and an element for biasing the movable member and the intermediate portion of the extended shape memory alloy member in that linear direction, so as to apply an elongation deformation to the extended shape memory alloy member. This linear motion actuator is inexpensive, compact, and light, and can be operated with a low voltage electrical supply, without being made bulky. Also, this linear motion actuator has an appropriate stroke to force relationship, and can be arranged to have a considerably large stroke.

Abstract: A circuit breaker includes first and second contactors having connecting/disconnecting means which normally keeps the two contactors in contact with each other. A shape memory alloy is mechanically connected to a predetermined portion of one of the connecting/disconnecting means of one contactor is electrically connected in parallel with a device to be protected, e.g. an electric circuit or an electric element. When a voltage of a predetermined value or more is applied to the device being protected, a current of a predetermined value or more passes through the shape memory alloy, whereby the alloy is heated to produce its shape memory effect. A shape recovering force is applied to the connecting/disconnecting means of the on contactor in a predetermined direction to separate the contactors.

Abstract: The invention relates to an electric control device for controlling displacement of a moving element (22) between two predetermined positions, said element (22) being associated with one or two electrically conductive return means (18, 30) having shape memory which exert substantially no return force on the element (22) so long as no electric current is passing therethrough, and which exert sufficient force thereon to displace it when an electric current is caused to pass therethrough, with an electric current being switched through one or other of the return means by a controlling switch (10). Once the moving element has reached the desired predetermined position, the electric current used to move it is interrupted by means of a toggle switch (24) operated by the moving element. The invention is applicable to selecting pneumatic functions, e.g. in the motor industry.

Abstract: There is disclosed a low loss circuit breaker including a housing, two exterior contacts, a pivotable arm, a means for biasing, a bifurcated member and a shape memory alloy element. The pivotable arm has a latching portion and a contact portion with the contact portion in electrical contact with one of the exterior contacts. The means for biasing exerts a biasing force with respect to the pivotable arm. The bifurcated member has a contact arm in touching relationship with the contact portion of the pivotable arm and is in electrical contact with the one of the exterior contacts through the contact portion of the pivotable arm. The bifurcated member further has a flexure arm cooperating with the latching portion of the pivotable arm wherein the flexure arm releasably restrains the pivotable arm against the biasing force exerted by the biasing means.

Abstract: An electrically controlled shape memory alloy actuator capable of being miniaturized for use in robotics and other fields. The actuator is made of a shape memory alloy wire which is torsioned end along its longitudinal axis and with its ends constrained against movement. A lever or other suitable element is attached to the wire at a desired point other than at a wire end. A plurality of electrical connections spaced along the wire define a plurality of different sections of the wire. The wire and attached control element is made to rotate by selectively applying voltages to the different sections of the wire to heat the individual sections.

Abstract: A slider lifter including a support structure, a flexure arm and a resilient means cantilevered from the support structure, and a shape memory alloy element operatively connected between the support structure and the resilient means, wherein the shape memory alloy element has a martensitic condition and an austenitic condition. The shape memory alloy element in one of the martensitic and austenitic conditions cooperates with the resilient means to elastically deform the flexure arm from an undeformed position to a deformed position. The shape memory alloy element in the other of the martensitic and austenitic conditions cooperates with the resilient means to both move away from the fexure arm, thereby allowing the flexure arm to return towards its undeformed position. It is most preferred that when the resilient means moves away from the flexure arm, the flexure arm and the resilient means are not in contact. This allows the flexure arm to return to its completely undeformed position.

Abstract: An over-temperature control for a thermostat uses an electrical contact actuator of a memory metal having an ability to change its physical configuration at a transition temperature to a "memory" shape. The contact actuator is arranged to bear against a cantilevered leaf spring having electrical contacts at a free end of the spring while the other fixed end of the spring is connected to complete an electrical circuit through the spring. The spring is also actuated by a bi-metallic element to produce a normal temperature responsive operation of the thermostat. The memory material actuator is arranged to provide a flexing of the spring cantilever to move the free end contact between a first and a second electrical terminal when the memory material is exposed to a transition temperature allowing the actuator to assume its "memory" shape.

Abstract: A temperature switch has an expansion element which consists of a metal alloy in which a martensitic structural transformation takes place within its working region, the phases concerned, austenite and martensite, having ordered lattice structures and the slightest possible difference in form. The expansion element preferably has the shape of a coil compression spring (7) which rests at one end against a bottom surface (9) of the housing (1) of the temperature switch and at the other end against a ram (4). This ram (4) serves to actuate a snap-switch mechanism (3) by which a switch contact (5) can be switched for movement against a fixed contact (6) or away from it.

Abstract: A thermally released switching mechanism which in a simple fashion and at a precisely defined switching point clearly interrupts the current to the motor when a preset, highest admissible temperature is exceeded, at least until the actual temperature has once against fallen below the highest admissible temperature. The thermally released switching mechanism is comprised of a lever element made of a memory element which, upon exceeding the highest permissible temperature set value, lifts the brush from a commutator or a slipring. This mechanism preferrably employs a memory element with a two-way effect. This thermal switching mechanism is suitable both for commutator motors with hammer or tubular brush holder systems as well as for slipring motors.

Abstract: A molded case circuit breaker wherein a movable contact arm (8) is operated between open and closed positions with a stationary contact (4b) by an operating mechanism which controls an overcenter toggle drive spring (12) and which is automatically openable upon sensing overload conditions by releasing a latched lever (10) for carrying the line of action of the drive spring (12) across the pivot (8a) of the movable contact arm (8). The current sensing trip means (16) for unlatching the latched lever (10) is formed of a shape memory effect alloy to provide a significant amount of travel of the latching end thereof in response to a narrow band of current thereby to insure release of the latch lever (10) without need for calibrating the breaker.

Abstract: A single temperature sensing switch is responsive to two or more different ambient temperatures is disclosed. A contact mechanism made up of stationary and movable contacts is opened and closed by serially interconnected first and second temperature-sensitive members, which are made of shape memorizing alloys having different transformation points. The switch may be associated with a compressor of an automotive air conditioning system in order to prevent it from being heated beyond a siezing level or cooled beyond a liquid compressing level.

Abstract: A device to provide overload protection for a shape memory metal (SMM) wire of an SMM-type actuator and to automatically compensate for cyclic creep and maintain the tension of the SMM wire. During normal operation, a restraining drum, in cooperation with a biasing spring, maintains the position of one end of the SMM wire so that the other end of the SMM wire can move an actuator. Under excessive loads, the restraining drum permits the first end of the SMM wire to move, thereby reducing the tension and preventing damage to the SMM actuator. When the excessive load is removed, the restraining drum permits the first end of the SMM wire to move under the influence of the biasing spring to its original position. By permitting the first end of the SMM wire to move in dependence upon the tension on the SMM wire, the device automatically takes up any slack caused by cyclic creep and maintains proper tension of the SMM wire.

Abstract: An arrangement for cooling an electric rotating machine such as an alternator of an automotive vehicle by means of a fan which is intermittently driven in accordance with the cooling requirements of the electric rotating machine. A heat source is associated with the electric rotating machine which is representative of the degree of heating of the rotating machine. The heat source may be the radiator of the rectifier diodes of the alternator. A heat sensitive means in the form of a spring of "memory alloy" controls the coupling/uncoupling with respect to the shaft of the rotating machine of the fan which is mounted free for rotation coaxially of the shaft of the machine. The heat sensitive means is in heat exchange relation with the heat source. The spring, for example, operates a lever which activates a control rod passing through the hollow shaft to control the coupling or clutching of the fan with respect to the rotating shaft.

Abstract: A shape-memory-effect actuator is provided having a shape-memory-alloy spring and a compensator spring. The alloy spring is operatively connected to a concentrically-mounted compensator spring by the use of a protective support housing which surrounds the alloy spring. The actuator includes a shape-memory-alloy spring and a compensator spring that regulates the operating conditions of the shape-memory-alloy spring to a chosen corresponding memory relaxation curve. The memory relaxation curve defines the actuator's operating stress, stroke and life.

Abstract: A shape memory metal actuator includes an actuator element that is secured at one end to an end fitting which is in turn secured to an overload protection spring. An adjustable screw is mounted to a frame and is positioned such that the overload protection spring biases the end fitting into contact with the adjustment screw. The end fitting lifts off of the adjustment screw when excessive stretching forces are applied to the actuator element. The adjustment screw can be moved to vary the rest position of the end fitting, thereby allowing manual compensation for cyclic creep of the actuator element.

Abstract: A shape memory metal (SMM) actuator includes an SMM actuator element mounted to an end fitting. An end portion of the actuator element adjacent the end fitting is cold formed to a thickness no more than 40% of the original thickness of the actuator element. This cold formed region extends by about 5 times the diameter of the actuator element away from the end fitting. The cold formed end region remains in the austenitic state, and is therefore relatively hard and strong. For this reason, the tendency of the actuator element to break at the end fitting is reduced, even though the end fitting acts as a temperature sink and maintains the cold formed end region below the transition temperature of the SMM actuator element.

Abstract: A mechanical actuator can be constructed by employing a plurality of memory metal actuator elements in parallel to control the amount of actuating force. In order to facilitate direct control by digital control signals provided by a computer or the like, the actuating elements may vary in stiffness according to a binary relationship. The cooling or reset time of the actuator elements can be reduced by employing Peltier junction cooling assemblies in the actuator.

Abstract: Disclosed is a shape memory effect actuator. The actuator comprises a biasing means which is normally biased in a first position and a shape memory alloy actuator element cooperatively engaged with the biasing means. The actuator element in a first unactivated condition is biased in the first position by the biasing means. In a second unactivated condition, the actuator element biases and retains the biasing means in a second position. The actuator element in an activated condition biases the biasing means in the second position. Also disclosed is a method of assembling an actuator and a cooperating apparatus and a method of operating the actuator.

Abstract: A switch device for controlling an electric motor which is used, for example, in a power window or sunroof of an automobile. The switch device includes a magnetically attractive piece, an electromagnet, sets of electrical switch contacts, and a spring coil of an alloy which, when heated to a predetermined temperature after being compressed, is restored to a released position.

Abstract: An electrothermal actuator assembly including a primary or armature member movable between first and second positions and biased to remain in either the first and second position to which it is moved with wires each made of shape memory material attached to the primary or armature member and acting in opposition to one another but, alternatively, when electrical current is passed through the respective wires to increase their temperature whereby they shorten in length to move the primary or armature. A switch supplies electrical current selectively through contacts interconnected by the primary or armature member, but only to one wire at a time for moving the armature from one position to another. The armature or primary member may move rectilinearly between first and second positions or may be rotatably supported for movement between first and second positions. The armature or primary member may also interconnect a set of load contacts to supply power to a load in one of the positions.

Abstract: A surge protector with first and second electrodes, with a heat sensitive member and with a contact member which is electrically connected with the first electrode and which is mounted so as to be brought into contact with the second electrode upon the temperature of the heat sensitive member reaching a predetermined value when receiving heat from the protector. In an embodiment, the heat-sensitive member is composed of a material whose shape is a function of its temperature, such as a shape memory alloy. The heat sensitive member can also serve as the contact member.

Abstract: A self-regulated actuator is disclosed having a shape-memory element which is heated preferably by passing electrical current therethrough and having a reset mechanism including a circuit-breaking mechanism. The shape-memory element provides the force to retract the actuator when heated. The reset mechanism utilizes a spring-biased latch plunger that resets the actuator as soon as it has retracted a specific distance. The reset mechanism also acts as a circuit-breaking mechanism to electrically interrupt current heating the shape-memory element. The reset mechanism provides near-instant reset time and overcomes the longer wait period otherwise associated with the natural cooling of the shape-memory element. The reset mechanism prevents overheating of the shape-memory element and precludes the necessity for additional hardware to interrupt the circuit after actuation is completed.

Abstract: A thermally responsive shape memory effect (SME) element (4) is positioned adjacent a fixed heater (40) for moving away from the heater to a switch actuating "memory" position as current induced temperature increases, thereby establishing changes in heat transfer coefficient between the heater (40) and thermally responsive element (4) for each increment of movement. An intermediate switch actuating lever (22) is carried on a movable range adjustment lever (16) to vary pretravel of an SME driven plunger (12). The SME element is resettable against a fixed stop (2c) for achieving accurate repetitive resetting of the device.

Abstract: A shape memory effect (SME) spring (20) is thermally responsive to currents sensed in itself or in a heater element (66) to pivot an actuator (16) against a bias spring (22) to operate a switch (32) in response to sensed currents above a given level. The actuator (16), bias spring (22) and SME spring (20) are carried by a pivotally mounted support beam (12) which is driven by an ambient temperature compensation mechanism (40,52) to change the amount of switch actuating travel of the actuator (16) in response to ambient temperature changes. The ambient temperature compensation mechanism comprises a pivotal lever (42,54) translationally coupled (42a,54a, 12b) to the support beam (12). In a first embodiment the lever (42,54) is driven by a temperature sensitive bimetal (46), and in a second embodiment it is driven by a temperature sensitive SME spring (58) biased to a reference position by an adjustable (62) spring (60).

Abstract: A shape-memory-effect actuator is provided having a shape-memory-alloy spring and a compensator spring. The alloy spring is operatively connected to a concentrically-mounted compensator spring by the use of a protective support housing which surrounds the alloy spring. The actuator includes a shape-memory-alloy spring and a compensator spring that regulates the operating conditions of the shape-memory-alloy spring to a chosen corresponding memory relaxation curve. The memory relaxation curve defines the actuator's operating stress, stroke and life.

Abstract: A fire alarm is provided with a temperature sensitive element formed of a shape memory alloy, which following cold working, upon heating to a critical temperature, typically for instance about 70.degree. C., returns to the original impressed shape and also retains this shape even after subsequent recooling. Due to the movement of the element there is triggered a self-holding alarm signal, either directly by closing contacts or indirectly. Resetting of the fire alarm can be accomplished by mechanically cold working the element, or by using two-way shape memory alloys through cooling to a lower temperature threshold which can be below room or ambient temperature. A further beneficial construction is realized by combining the arrangement with a different type of fire detection or sensing element, for instance by arranging a shape memory alloy element in a scattered radiation-smoke detector.

Abstract: A flux shifting circuit breaker trip device includes a permanent magnet for developing a holding flux to create a magnetic force on a plunger sufficient to hold it in its retracted position in opposition to a spring. An electromagnet energized under the control of a static trip unit develops flux in opposition to this holding flux, whereupon the spring becomes overpowering and propels the plunger to its extended position effecting a circuit protective trip function. Temperature responsive means are also included to increase the reluctance in a region of the holding flux path in response to an excessive ambient temperature condition within the breaker enclosure, whereupon the spring becomes empowered to motivate a thermal override trip function.

Abstract: An electrical overload circuit breaker utilizes as the current-responsive tripping mechanism a solenoid, the coil of which is constituted by a helical spring of shape memory effect material and which mechanically acts on the armature. There is a non-SME spring which also acts on the armature but in a direction opposing the SME spring. The current is passed through the SME spring and, when it becomes excessive, the armature is urged both mechanically and electromagnetically in a tripping direction.

Abstract: Thermal switch, including a switching element formed of a coherently structured vitreous metal alloy. The switching element being in a vitreous-amorphous state and having a higher strength at a lower first temperature range, and in a crystalline state and having a lower strength at a higher second temperature range. A tensioning device cooperating with the switching element for exerting a force thereon which is sufficient to break the switching element in the crystalline state and insufficient to break the switching element in the vitreous amorphous state. A device for triggering a switching process in response to the breaking of the switching element in the vicinity of a transition from the first to the second temperature range. An exchangeable cassette assembly for housing the switching element, and a method for protecting circuits against overcurrents using the thermal switch.

Abstract: A thermoelectric switch having a current conducting triggering element made from a shape memory alloy exhibiting a two way temperature effect and coupled to a stressing device which exerts a force on the triggering element to thereby determine the switching temperature of the thermoelectric switch. Mechanical switching amplification is actuated by the triggering element to interrupt current flow through the thermoelectric switch.

Abstract: An electrical switch responsive to air flow having an insulated base with a snap action switch mounted thereupon. The snap action switch with an actuating pin impinging on one end of a bar that is mounted on a pivot and axially movable. The other end of the bar extends to clamp an alloy wire exhibiting a high linear coefficient of expansion and which is tied to a spring fixed on the insulated base. From same said spring a second alloy wire is extended to a fixed point on the insulated based in close proximity to the clamp on the bar. The first alloy wire is internally heated by a fixed voltage, the second alloy wire is internally heated by a voltage that is less than the fixed voltage and which is applied only when the snap action switch is deactuated. The second alloy wire provides means for obtaining temperature compensation and smaller differential between the actuating and deactuating air flow.