Abstract: The invention relates to a thermally triggerable indication or switching device, having a movable, mechanically preloaded slide which directly or indirectly triggers or actuates the indication or switching device, and having a preformed part which changes its state of aggregation under the effect of heat, the preformed part, in the functional state, being adapted to be arranged so as to block the movable slide. According to the invention, in the initial state, the preformed part is loosely located in a receiving space. For transferring the preformed part to the functional state, the slide is moved in a position such that a gap space opens between the slide and a slide stop, wherein the preformed part enters the gap space and the slide is simultaneously preloaded.

Abstract: Certain aspects are directed to a thermal fuse for preventing overheating of RF devices in a telecommunication system. In one embodiment, an RF thermal fuse comprises a body: a conductive bolt positioned in the body, the conductive bolt having a length sufficient to provide an impedance at a point of protection on a transmission line in response to the conductive bolt contacting a live conductor of the transmission line, wherein the impedance reflects a portion of the incident power of an RF signal from an RF signal source; and a driving mechanism that causes the conductive bolt to selectively contact the live conductor in response to an event.

Abstract: In aspects of the disclosure, a fuel cartridge wherein the fuel is in a powdered form is admixed with inert materials such as alumina or other ceramics to improve thermal conductivity. Said cartridge having fuel zones, heating zones, and controllers to selectively heat fuel zones and thereby generate hydrogen via decomposition of fuel is disclosed.

Abstract: A thermal switch comprises a first and second electrically conducting terminals and a pre-stressable electrically conducting connecting device such as a compression spring member. The connecting device, in a compressed state, contacts at most one of the first and second terminals, and, in a released state, electrically connects the first and second terminals. The thermal switch further comprises a retainer device retaining the connecting device in the compressed state. The retainer device comprises a retaining material that melts at or above a predetermined temperature for releasing the connecting device into the released state. In the compressed state of the connecting device, the first and second terminals are electrically insulated from each other by a hollow space formed between the connecting device and at least one of the first and second terminals.

Abstract: A modular by-pass device of an electrical component comprises a housing comprising a movable means of sealing and a plurality of conducting terminals, each having one end connected to a terminal of the electrical component circuit, and each having other end fastened to the wall of the housing and projecting into the interior of the housing to form a contact post. An actuator providing transposition between two positions of a control device comprise a plunger shaft and a spring arranged in the space formed between the plunger shaft and the internal wall of the housing. A trigger comprises a retention device of the plunger shaft held in place by a fusible material. A reversing switch comprises a contact zone providing electrical continuity between two contact posts of the terminals of the housing. The claimed invention finds application in the isolation and short-circuiting of a battery element, which has become defective.

Abstract: A reflowable thermal fuse includes a conduction element with first and second ends, disposed within a housing. The reflowable thermal fuse also includes an elastic element disposed within the housing and adapted to apply force on the conduction element in an activated state of the reflowable thermal fuse. A restraining element is utilized to secure the elastic element and prevent the elastic element from applying force on the conduction element in an installation state of the reflowable thermal fuse. Application of an activating current through the restraining element causes the restraining element to break and thereby release the elastic element and place the reflowable thermal fuse in the activated state.

Abstract: A modular by-pass device of an electrical component includes a housing possessing a movable means of sealing, and is equipped with conducting terminals, one of whose ends is connected to one of the terminals of the electrical component circuit, the other end being fastened to the wall of the housing projecting into the interior of the housing and constituting a contact post. An actuator providing transposition between two positions of a control device include a plunger shaft and a spring arranged in the space formed between the plunger shaft and the internal wall of the housing. A trigger includes a retention device of the plunger shaft held in place by a fusible material. A reversing switch includes a contact zone providing electrical continuity between two contact posts of the terminals carried by the housing. The disclosed embodiments finds application more particularly in the isolation and short-circuiting of a battery element, which has become defective.

Abstract: A method and apparatus for rapidly severing a decoy towline extending from an aircraft by a mechanical spring actuated cutting blade and a thermal fuse type of release mechanism eliminating a pyrotechnic actuation device. The cutting blade is biased toward cutting engagement with the towline by a preloaded coil compression spring retained in the loaded position by a length of a polymer cord. The polymer cord has a heater wire wrapped about a portion of the cord which is connected to a DC voltage supply. The heater wire melts the cords when electrically connected to the DC power supply which releases the restraint on the spring which then drives the cutting blade into severing engagement with the towline.

Abstract: An apparatus for the cutting of an electrical conductor has an electrical conductor arranged in a housing, a pyrotechnic drive and a cutting device. After the triggering of the drive, the cutting device enters into engagement with the conductor to cut it.

Abstract: In order to prevent erroneous operation caused by shrinking of a thermal pellet due to sublimation or softening of the thermal pellet when current is applied, a thermal pellet type thermal fuse includes a metal casing, a first lead and a second lead leading out from the metal casing, a movable electrode, a thermal pellet, a strong compression spring, and a weak compression spring. Difference in temperature is achieved at the surface of the metal casing by selecting different diameters or wires for the first lead and the second lead, or by providing a heat-radiating plate.

Abstract: The invention relates to a device for isolating an electric circuit, especially for high current intensities, with a housing (1) in which is provided at least one electrical conductor element (3) which presents an isolating area (9) and which can be wired in such manner into the severable electric circuit that the isolating current path passes over the conductor element (3) and with activatable means(13, 7; 3, 9, 7), provided in or at housing (1) for generating a trigger pressure which acts directly upon the isolating area (9) and/or via a driving surface (17, 23, 39, 41), in its original position, impinging upon the isolating area (9), wherein the isolating area (9) and/or the driving surface (17, 23, 39, 41) is designed in such manner that after activation of the means (13, 7; 3, 9, 7) the isolating area (9) is totally isolated or broken out, or the cross-section of the isolating area (9) is reduced.

Abstract: A circuit breaker device including a first connection terminal, a second connection terminal, a heating portion electrically interconnecting the first connection terminal and the second connection terminal, and a claw lockingly engaged with the heating portion. The claw is configured to be melted by the heating portion to allow the heating portion to move apart from the first connection terminal and the second connection terminal for electrical disconnection.

Abstract: A circuit-breaking apparatus is formed of an insulating housing, first and second electrodes located at both ends of the insulating housing, a detonator located in the first electrode, a lead connected to the detonator for supplying an electric current to the detonator when the detonator is actuated, and a conductor disposed in the insulating housing. The conductor includes a fixed portion electrically connected to the first electrode, a circuit-breaking rod having narrow portions at both ends, and a barrel connected to the second electrode and having a cavity. The circuit-breaking rod is coupled to the fixed portion and the barrel through the narrow portions. The barrel has a locking section for locking in the cavity the circuit-breaking rod that has been shifted toward the second electrode due to cutoff of the narrow portions caused by the explosion of the detonator.

Abstract: A temperature sensor has a flexible nylon tube connected by a fluid-tight coupling to a metal bellows within a metal housing. The interior of the tube and bellows is filled with a pressurized liquid whose critical temperature corresponds to a threshold temperature to be sensed. The pressurized liquid holds the bellows extended, holding an actuating piston back against the action of a spring. When the threshold temperature is reached, the liquid in the tube must boil and ruptures the tube, causing the bellows to collapse and the actuating piston to move. A projecting actuator then mechanically initiates a response such as the closing of a damper in an air-conditioning duct.

Abstract: A thermal cutoff including a dielectric bushing having opposite ends and a hole therethrough. A wire lead received through the hole has an enlarged contact thereon adjacent one bushing end, and an enlarged deformation thereon adjacent the other bushing end. The contact and deformation prevent relative longitudinal movement between the bushing and lead.

Abstract: A thermal cutoff construction, member therefor and methods of making the same are provided, the thermal cutoff construction having an electrical switching unit that changes its operating condition when the member therein melts by being heated to a certain temperature for the particular material that forms the member being utilized. The material of the member comprises 4-methylumbelliferone.

Abstract: Apparatus and methods for assembling a thermally-actuated cut-off link having a casing, a closure, split along its length to form a slot, a power lead, one end of which extends from the casing through a neutral passage formed in the closure, the other end of which terminates in a pair of outwardly deformed, inwardly deformable contact arms forced into low-resistance contact with an inner conductive surface of the casing, a fusible pellet, and a spring-biased arm-deforming member which, responsive to deform the contact arms away from the inner conductive surface to interrupt the flow of current through the cut-off link. The closure is secured to the casing by crimping the casing to grippingly contact the power lead and to narrow the slot. Relatively viscous sealant, placed in an enlarged section of the closure passage is drawn into the narrowed slot by capillary action, and is thereafter cured.

Abstract: A single use thermal switch having a tubular casing within which a mechanical isolation cage is axially movable. The cage is normally urged by a helical compression spring against a fusible pellet which melts at a temperature at which it is desired to disconnect the electrical circuit. An electrically conductive contact member extending transversely through the isolation cage is normally urged by a helical compression spring toward one end of the cage and against the end of one electrical lead that is coaxial with the casing. The contact member is foldable along a line across its center. The force of the contact member pressed against the end of the lead urges the contact member to fold to cause the ends thereof to be forced against the inside wall of the casing to establish electrical connection between the casing and the lead through the contact member.

Abstract: A pyrotechnical cartridge or motor (5) is actuated by electric firing from its head (5c), and pushes the insulating piston (3) which separates by shearing the intermediate connecting portion (1b) of the destructible conductor (1) and pushes it into the bore (1e) together with the rod (9), the conical end (9a) of which becomes wedged within the plug (10) so as to form a brake. The fuse cartridges (13) then open the circuit in a fully safe manner.The present invention is useful for instance under the control of overcurrent detectors.

Abstract: A thermosensitive fuse includes a cylindrical metallic casing having one end closed and the other end opened. The closed end of the casing is connected with a first conductor that extends outwardly from the casing and the opened end is fittingly mounted with a bushing carrying a second conductor. One end of the second conductor projects into the casing and the other end extends outwardly from the casing. Provided in the casing are an organic substance of solid state from the bottom of the casing to an intermediate level thereof, a contact member of slanted cylinder having a diameter smaller than the inner diameter of the casing, a first spring extending between the organic substance and one end of the contact member in a compressed manner, and a second spring, which is weaker than the first spring, extending between the projected end of the conductor and the other end of the contact member in a compressed manner.

Abstract: A temperature responsive safety switch including an insulating housing provided with a recess, a pair of electrically conductive contact elements mounted in the housing and defining an electric current path extending through the housing, one of the contact elements being a spring element which is internally stressed to tend to separate from the other contact element, a solder body, a plunger displaceably mounted in the housing and supported between the body and the spring element to maintain the contact elements in contact with one another when the body has not melted, and a hollow cylindrical sleeve member mounted in the housing recess and enclosing the solder body and which is oriented in the displacement direction of the plunger, the end of the plunger remote from the contact spring extending into the sleeve member with play in the direction perpendicular to the longitudinal axis of the sleeve member, and recess presenting a space around the sleeve member sufficient to receive the entire mass of solder whe

Abstract: A temperature responsive electrical switch construction having electrical contacts operated by a stem of a piston and cylinder type thermal device carried by the construction, the contacts comprising a plurality of pairs of cooperating contacts arranged to have each cooperating pair thereof operated serially by the stem as the thermal device senses different predetermined temperatures. Each pair of cooperating contacts comprises a fixed contact and a movable contact. The construction has a plurality of terminals projecting therefrom and being substantially parallel to each other and to the stem, the fixed contacts being respectively carried by the terminals.

Abstract: A temperature responsive terminal pin construction having an aligned pair of terminal pin parts inserted in the opposite ends of a casing with the inner ends of the pin parts in spaced apart relation, a split ring collet surrounding the pin parts, the collet being axially displaceable under spring pressure from a first position of use in which the collet makes electrical contact with both pin parts to a second position in which the collet is out of contact with one of the pin parts, the collet being held in its first position by the nose of thermosensitive annular ring secured to the casing, the nose of the ring engaging an enlarged head on the collet. Excessive heating of the terminal pins will cause the nose of the thermosensitive ring to melt at a predetermined temperature to release the collet for axial movement. Coacting cam surfaces on the nose of the thermosensitive ring and the head of the collet act to urge the collet into tight electrical contact with the pin parts.

Abstract: A one-piece wire lead has intermediate its ends a thin, flattened section which is seated against a recessed die surface that is formed on one end wall of a hermetically sealed chamber in a preferably transparent, paraboloidally-shaped plastic housing. The two cylindrical leg sections of the lead project out of the opposite end of the chamber for connection in series with a conductor in a circuit that is to be protected. A plastic, electrically non-conductive, spring-loaded sabot is mounted to reciprocate in the chamber between a retracted position in which a sharp cutting edge on the forward end thereof faces one side of the flattened section of the lead, and an advanced position in which the sabot cutting edge has cut through the flattened lead section, and has extended into a recess in the die surface. Normally a compacted, granular thermal plug is cast or molded around either the sharp cutting edge of the sabot, or its operating spring, thereby normally to retain the sabot in its retracted position.

Abstract: A temperature-sensitive fuse comprises a first electric conductor electrically connected to one end of an electrically conductive casing; a second electric conductor which is connected to the other end of the casing in such a manner so as to be electrically insulated therefrom; a temperature-sensitive, fusible pellet disposed in the end portion of the casing containing the first conductor; a movable disc member which is disposed between the fusible pellet and the top portion of the second conductor, normally in contact with the top portion of the second conductor and the inner wall of the casing, and held by a spring in such a manner that when the fusible pellet melts and collapses at a predetermined ambient temperature, the movable disc is moved away from the top portion of the second conductor.

Abstract: A thermally actuatable electrical switch construction having a housing carrying an electrically insulating end plug provided with an opening passing therethrough and in which a portion of a conductive lead is disposed so that opposite ends of the lead extend beyond opposed ends of the plug and respectively define a fixed contact inside the housing and a terminal outside the housing, the portion of the lead being retained in the opening by a sealing compound disposed in the opening and extending around the portion of the lead and interlocking therewith to tend to prevent axial movement of the lead into the housing as well as to tend to prevent rotational movement of the lead relative to the end plug. The portion of the lead has a series of at least two convolutions that interlock with the sealing compound in the opening of the end plug. The two convolutions respectively have apexes that respectively engage the internal surface of the end plug substantially on opposite sides thereof.

Abstract: A thermally actuatable electrical switch construction having a housing carrying an electrically insulating end plug provided with an opening passing therethrough and in which a portion of a conductive lead is disposed so that opposite ends of the lead extend beyond opposed ends of the plug and respectively define a fixed contact inside the housing and a terminal outside the housing, the portion of the lead being retained in the opening by a sealing compound disposed in the opening and extending around the portion of the lead and interlocking therewith to tend to prevent axial movement of the lead into the housing as well as to tend to prevent rotational movement of the lead relative to the end plug. The portion of the lead has a substantially unrecessed cylindrical peripheral surface throughout the entire length thereof and has a plurality of outwardly extending cog-like members that extend outwardly from the peripheral surface and interlock with the sealing compound in the opening of the end plug.

Abstract: A thermally actuatable electrical switch construction having a housing carrying an electrically insulating end plug provided with an opening passing therethrough and in which a portion of a conductive lead is disposed so that opposed ends of the lead extend beyond opposed ends of the plug and respectively define a fixed contact inside the housing and a terminal outside the housing, the portion of the lead being retained in the opening by a sealing compound disposed in the opening and extending around the portion of the lead and interlocking therewith to tend to prevent axial movement of the lead into the housing as well as to tend to prevent rotational movement of the lead relative to the end plug.

Abstract: An off-centered hour glass shaped coil spring, having a particular utility in thermally responsive switches to bias a sandwich of switch forming elements including a pellet of meltable material and comprising outermost spiral turns which are the coils of maximum diameter at opposite ends of the coil, and off-centered intermediate turns of lesser diameter between the same. These various turns of the coil are such that when the coil spring is compressed, the contiguous portions of the turns will overlap partially and nestle together, so that the longitudinal dimensions of the compressed spring are reduced from that of a conventional coil spring of the same size.

Abstract: A thermal cutout fuse comprises a fuse housing, a first lead wire penetrated into the housing interior, a movable contact capable of being turned aslant in the radial direction and energized constantly in the horizontal direction, the movable contact connected to the leading end of the first lead wire, a stationary contact disposed so as to encircle the movable contact, a second lead wire connected to the stationary contact, a solid thermally sensitive pellet capable of melting at a prescribed unsafe temperature, the thermally sensitive pellet disposed inside the housing opposite the movable contact, and a stopper adapted to turn the movable contact aslant and keep it in contact with the stationary contact, the stopper interposed between the thermally sensitive pellet and the movable contact.

Abstract: A thermally actuatable electrical switch construction having a resilient contact member normally biased into electrical contact with a stationary contact member while a temperature sensitive member of the construction is in a solid condition and normally tending to spring out of contact with the stationary contact member by the natural bias of the resilient contact member when the temperature sensitive member is rendered non-solid by sensing a temperature above a predetermined temperature. The construction carries a guide member operatively associated with the resilient contact member to provide a guide for the resilient contact member that will substantially insure that the resilient contact member will move and be maintained out of contact with the stationary contact member after the temperature sensitive member has been rendered non-solid.

Abstract: A thermally actuatable electrical switch construction having a resilient contact member normally biased into electrical contact with a stationary contact member while a temperature sensitive member of the construction is in a solid condition and normally springing out of contact with the stationary contact member by the natural bias of the resilient contact member when the temperature sensitive member is rendered non-solid by sensing a temperature above a predetermined temperature, a guide member being carried by the construction and being operatively associated with the resilient contact member to provide a guide for the resilient contact member that will substantially insure that the resilient contact member will move and be maintained out of contact with the stationary contact member after the temperature sensitive member has been rendered non-solid.

Abstract: An ambient thermally actuated switch comprises a power lead extending longitudinally into and insulated from one end of a metal casing. The power lead made of a soft low resistance material like copper is bifurcated at its inner end to form outwardly inclining arms which, in a normally closed embodiment of the switch, makes contact with the inner surface of the casing. The arms are pressed against an insulating backing member so that the arms expand outwardly into a low resistance contact with the casing. The backing member forms part of a spring-urged, longitudinally extending, sandwich of elements extending between the ends of the casing and preferably comprising a pellet of meltable material, a first partially compressed spring, said backing member, arm-deforming means positioned contiguous to and adapted to collapse said arms when released to do so, and a second fully compressed spring applying a force acting on said deforming means to force it into an arm-collapsing position when the pellet melts.

Abstract: The thermal switch of the present invention relates to thermal switches in which an organic pellet melts at a predetermined temperature which thereby allows the switch to change from a closed to an open state. More particularly, the switch is of the axial lead type wherein one of the leads is connected to the outside of a metallic housing for the device, and the other lead passes through an insulator into the interior of the housing. A thermally-sensitive pellet is positioned in the bottom of the metallic housing and a contact member is positioned in the gap between the pellet and the head of the insulated lead. A coiled spring encircles the insulated lead and forces the contact member toward the temperature-sensing pellet. The electrically conductive contact is formed with a bottom which either engages the pellet, or a wafer which is in contact with the pellet, and a top which is partially open and has a pair of inwardly bent ends that contact the head of the insulated lead at an angle.

Abstract: Gas filled surge arrester is equipped with a thermally responsive short circuit switch for overload protection and air gap shorting for back up overload protection. The switch and air gap device is disclosed in three orientations; namely, separate and external to the gas tube; unitized with the air gap interior to the switch; and unitized with the air gap exterior to the switch. The unitized arrangements have application in circuitry with gas tubes where back up air gap protection of the thermal switch is desired.

Abstract: A temperature-responsive electrical switch is provided which has a pair of axial leads, one of which is connected to the cylindrically-shaped electrically conductive housing, and the other of which passes through an insulator into the interior of the housing. A cylindrical-shaped, slideable electrical contact which is open at one end is positioned in the housing. A coil spring is located inside the slideable contact between the bottom end of the contact and an enlarged section of the insulator. The contact has a plurality of spring fingers which are integrally formed from the bottom of the contact and which project upwardly from the bottom of the contact toward the head of the insulated lead. A thermally-sensitive pellet, which melts at a predetermined temperature and is formed to have a cavity in it, is positioned below the spring fingers. The pellet is dimensioned transversely so as to force the fingers into contact with the head of the insulated lead.

Abstract: A control apparatus is disclosed for regulating the movement of a control stem which is biased in a given direction. The apparatus comprises a housing forming a chamber and a plurality of passages. The chamber receives the control stem in its direction of bias, the latter abutting against a restraining sphere disposed in the chamber. A pair of pistons are movably disposed in remaining ones of the passages to maintain the sphere in the chamber. The pistons are movable to allow the sphere to enter a passage so that the stem can move further into the chamber. The pistons can be moved manually or automatically, as by means of a fusible element which melts in response to the heat of a fire.

Abstract: The manually actuable electric switch has a fusible element which melts on subjection to a predetermined temperature to discontinue the flow of electric current through the switch. The structure is incapable of operation on melting of the fusible element without replacement of the element, thereby preventing accidental reactivation of the switch prior to termination of the unusual thermal conditions causative of the melting of the element. A manually operable plunger normally used to open and close the switch is mechanically connected to the stem of the switch through the fusible element. Melting of the element severs the mechanical connection between the plunger and the switch.

Abstract: Conductive caps are respectively put on both ends of an insulating cylindrical member and a pair of cup-shaped contactors are disposed in the insulating cylindrical member in a manner to be movable relative to each other. A repulsive force is provided by a pair of biasing elements located between the pair of cup-shaped contactors through a fusible member to electrically interconnect the conductive caps. When the fusible member is fused at a predetermined temperature, the biasing force of one of the biasing elements weakens and the biasing force of the other biasing element increases to move the pair of cup-shaped contactors toward each other, thereby to electrically disconnect the conductive caps from each other.

Abstract: A temperature responsive current interrupter in which two conductors are connected by electrically conductive, low-melting-point fusible elements respectively mounted on the conductors and a connector element interconnecting the fusible elements and urged against an electrically non-conductive high-melting-point fusible element, the connector element being moved into a position separate from at least one of the conductors when the high-melting-point fusible element is melted by heat.

Abstract: A thermally actuatable electrical switch construction having a deformable contact member normally disposed in electrical contact with a stationary contact member while a temperature sensitive member of the construction is in a solid condition and being deformed out of contact with the stationary contact member by deforming means of the construction when the temperature sensitive member is rendered non-solid by sensing a temperature above a predetermined temperature, the deformable contact member being deformed in a direction toward the temperature sensitive member by the deforming means when the temperature sensitive member is rendered non-solid and being carried by a lead that projects into the switch construction whereby the lead and the deformable contact member define a subassembly that is adapted to be initially inserted into the construction to be secured thereto.

Abstract: An electrical connector system including a cable terminator having a conductive probe and a bushing having a bore contact mounted for reciprocal movement in an electrically conductive tubular member and a fusible member positioned between the bore contact and the conductive member, the fusible member being connected to fuse in response to fault current produced by a prestrike arc to increase the pressure within the tubular member to force the bore contact into electrical engagement with the probe in the terminator.

Abstract: A normally open temperature sensitive electrical switching device includes a heat fusible electrically conductive pellet which melts and provides an electrically conductive path through the switching device at a predetermined temperature level and, further, includes arc contacts defining an air gap across which arcing will occur when a sufficient potential is supplied to the switching device. A first electrically conductive electrode and second electrically conductive electrode are electrically connected to first and second electrical leads provided for an electrical connection to the device. A nonconductive mounting arrangement holds the first and second electrodes in spaced relation. The heat fusible conductive pellet is positioned in contact with the second electrode and defines the air gap of predetermined dimension with the first electrode.

Abstract: A temperature sensitive normally open electrical switching device has a pair of normally isolated current carrying leads. A casing defines a central cavity and encloses first and second electrodes which are electrically connected to separate ones of the leads. An electrically conductive, fusible pellet is positioned in the cavity and melts at predetermined temperature to form an electrically conductive path between the electrodes. A spring and a nonconductive spacer apply a force to the pellet which will cause the pellet to collapse once the pellet material is fused regardless of the formation of an oxide layer on the pellet surface.

Abstract: A thermally responsive electric switch which has an insulative member movably oriented within the switch's housing. A conductive element is positioned within the movable member to electrically interconnect the spaced end portions of two lead-in wires also positioned within the housing. A thin layer of fusible material (e.g. gallium) is positioned on the ends of the lead-in wires and in contact with the conductive element when the movable member occupies a first position within the housing.

Abstract: A thermal fuse comprises an electrically and thermally conductive housing hermetically sealing switch parts of a fusible temperature-sensitive pellet, metallic plates, compression springs and a slidable resilient contact member. The contact member has a center contact portion at its bottom base and a peripheral contact portion with a plurality of tongues extending from the bottom base. The contact member of resilient conductive material is shaped to form a portion sloping over the bottom base and to form peripheral tongues extending relative to the flat surface of the assembled metallic plate when no external force is applied.

Abstract: The present thermal fuse comprises an electrically and thermally conductive housing for hermetically sealing the switching parts and a fusible, temperature sensitive pellet in said housing. The pellet is preferably molded to have a cylindrical shape or body provided with one cavity or several cavities and assembled in the housing, whereby the outside pellet surface contacts the inner surface of the housing. The cavity or cavities take up about 5 to 50 percent of the whole cross sectional area of the pellet. The pellet is made of a mixture of organic and inorganic substances preferably so as to accelerate the fusing function of the pellet when the temperature rises above the melting point of the major component of the organic materials. The cavity or cavities of the pellet greatly facilitate a large and rapid shrinkage in volume and the addition of inorganic substance provides a large thermal conductivity of the pellet, whereby a rapid and exact fuse action is accomplished.

Abstract: A thermal switch having a tubular metal casing within which a fusible pellet normally holds an axially slidable electrical contact disk in contact with an electrical lead. The body of the electrical lead extends through a ceramic bushing and out of the casing for electrical connection, and it is formed with at least one radially-extending relief lying within the bore of the ceramic bushing. A sealing resin within the bore of the ceramic bushing and around the lead retains the lead in the bushing both in normal use and after the fusible pellet has melted and the electrical connection is broken.

Abstract: A heat-sensitive protector, that is connectable into an electric circuit, has an elongated, effectively non-fusing element which performs the function of a connector as long as that protector is intact, and thereafter moves fron a retracted position to an extended position to perform the function of an indicator when that protector responds to heat to open that circuit. That element spans the full distance between the terminals of that heat-sensitive protector.

Abstract: An electrical wire cutting circuit breaker in which a wire cutting piston within a housing moves from a rest position to a wire cutting position under the impetus of a compression spring. The piston is normally retained in its rest position against the force of the compression spring by a retainer held in the path of the piston by a fusible stop. The retainer is resiliently biased out of the path of the piston so that when the fusible stop melts and flows at a predetermined elevated temperature the retainer will release the piston which is propelled by the compression spring and builds up kinetic energy sufficient to cut an electrical wire.