Abstract: A thermal overload mechanism for providing protection to tip and ring conductors in a telecommunications system in the event of a power cross occurrence of telephone lines with power lines. The thermal overload mechanism includes a clip having front and rear spring members dimensioned for seating about a spacer element. The spacer element includes one or more recesses defined therein for accommodating securement of solid state devices. The recesses formed in the spacer elements contain a breachable membrane or wall which is breakable in the event the membrane temperature exceeds a predetermined temperature such as a temperature occurring in the event of a power cross situation. A contact configured for seating within the recess between the membrane and solid state device is provided for maintaining electrical contact with the tip and ring wires.

Abstract: A fusion apparatus is equipped with a fuse, a solid combustion agent, an igniting device, and a spring. The solid combustion agent and the igniting device are accommodated within an inner casing. The inner casing is disposed in the vicinity of, or in contact with, the fuse. The inner casing and the fuse are covered by an outer casing. The spring is disposed between the outer casing and the inner casing and urges the inner casing containing the solid combustion agent therein toward the fuse. When the igniting device receives a current supplied from the outside, the solid combustion agent is combusted by the ignition made by the igniting device and the resulting combustion heat softens the fuse. At this time, since the inner casing is pressing the fuse by means of the spring, the fuse is easily broken.

Abstract: An current breaking device is interposed between a battery for a vehicle and an electric load. When a circuit cut-off signal is generated from a control unit due to an automobile's collision, the current breaking device allows respective capsules 40 in a power distributing box to be heated to melt a conductive resin plate 2. Therefore, it is possible to stop the power supply from a battery to an electric load.

Abstract: An electrically conductive contact pin having a temperature fuse function includes an electricity conducting element formed in an approximately cylindrical shape divided into an electrode contact portion and an outer electric contact portion, a holding body for holding the electricity conducting element provided around the outer electric contact portion such that the holding body may slide along the surface of the outer contact portion, a pressing member for pressing the outer electric contact portion upward provided between the holding body and the electrode contact portion, and an actuator for actuating to expand the distance between the electrode contact portion and the outer electric contact portion upon melting of the heat sensitive electrically conductive melt body. The electrically conductive contact pin may be consisted of two electricity conducting route by having a measurement element inside.

Abstract: A new type of high temperature thermal disconnect has been developed to protect electrical and mechanical equipment from damage caused by operation at extreme temperatures. These thermal disconnects allow continuous operation at temperatures ranging from 250.degree. C. to 450.degree. C., while rapidly terminating operation at temperatures 50.degree. C. to 150.degree. C. higher than the continuous operating temperature.

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

Abstract: A circuit breaking device includes a socket provided on the way of a circuit, a plug movably disposed in a direction that the plug is inserted into and removed from the socket, an explosive exploding in response to a trigger signal given thereto to thereby drive the plug by explosion force to move advanced, and the plug which is normally disposed in a retreated position at where the plug is in a conductive state with said socket, while the plug is in a non-conductive state with said socket when the plug moves to an advanced position.

Abstract: A fluorescent lamp thermal fuse arrangement is disclosed. The arrangement in a preferred embodiment comprises a fluorescent glass tube lamp, a thermal fuse wrapped externally around an end of the lamp, electrically insulated mechanical means, lead portions of the thermal fuse and strain relief, and a thermally and electrically insulating protective cover placed over the thermal fuse to concentrate heat around the fuse and to electrically isolate the lamp end from the surrounding environment. The lamp has a maximum normal operating temperature, a coating of emissive material on a cathode of the lamp, a plurality of lamp cathode leads, and a termination electrically connected to a fluorescent lamp power source. The thermal fuse is electrically connected in series between at least one lamp cathode lead and the termination. The protective cover provides electrical insulation to the surrounding environment and a small space for melted fuse material to flow regardless of lamp orientation.

Abstract: Between a relay terminal of a direct current motor and a contact terminal of an electromagnetic switch, there is provided a fuse which is melted to cut off an electric current upon reaching a predetermined temperature. By properly setting the predetermined temperature at which the fuse melts, it is possible to make the fuse heated to a high temperature and melted in a relatively short time to cut off the electric current in the event of, for example, a continuous operative condition caused due to such a failure as fusion adhesion of a movable contact point with a B-terminal and an M-terminal or fusion adhesion of a contact point mechanism outside a starter, or an overcurrent supply condition caused upon a rotor being locked.

Abstract: A thermal fuse includes a first electrical contact extending through and engaged in electrical contact with a second contact. A spring is compressed between the first and second contacts. A thermally deformable pin retains the second contact against the compressed spring. The pin is responsive to a high temperature condition such that the pin deforms, thereby allowing the spring to disengage the first and second contacts.

Abstract: A radiant-energy configurable fuse structure and array are provided in which the fuse body of the fuse is wider than the fuse connection terminals. The fuse body can be circular or polygonal to capture more of the radiant energy from a targeting beam, which reduces the energy required to blow the fuse. As a result, unrelated circuit elements and patterned lines can be placed closer together in a laser fuse array, thereby increasing the packing density of such arrays.

Abstract: A temperature fuse for use in an electric circuit provided in an automobile or the like. The temperature fuse includes a pressure-contact terminal having a pressure-contact blade, a temperature opening and closing member having one end connected electrically to the pressure-contact terminal, a signal wire connecting terminal connected electrically to the other end of the temperature opening and closing member, and an insulating case for receiving therein the pressure-contact terminal and the temperature opening and closing member in such a manner that at least the pressure-contact blade and the signal wire connecting terminal are exposed outwardly from the insulating case.

Abstract: A thermal fuse includes a resilient coil portion with a turn of at least 360.degree.. Two spring arms have two upper portions connected to and integrally formed with two ends of the coil portion, and two lower portions extending from the upper portions and formed with two contact locations for connection to two circuit contacts of the circuit board. At least one of the contact locations is to be soldered on the circuit board. During the connection of the contact locations to the circuit contacts, the lower portions are kept in a tensed state by moving the contact locations toward each other so as to generate a biasing force to bias the lower portions away from each other.

Abstract: A pyrotechnic high-current fuse element in which a current conductor located in a circuit to be protected is interrupted or displaced by ignition of a pyrotechnic charge when the current strength in the circuit exceeds a threshold value includes a separate component that can be installed in the circuit to be protected, to which component the ends of a current conductor to be cut are connected.

Abstract: A blown fuse indicator, having an insulating element, a current-carrying element overlaying the insulating element, and a substantially transparent window. A chemical composition coats at least a portion of the insulating element. The improvement comprises a meltable link in generally parallel proximity to the insulating element. The meltable link, which can be made of solder, melts to open an indicating circuit of the blown fuse indicator upon predetermined thermal overload conditions.

Abstract: A simplified method of manufacturing an electrothermal fuse includes the steps of screening conductive epoxy onto fuse link termination pads, placing a metal alloy fuse link into the conductive epoxy on the termination pads, curing the conductive epoxy, applying deoxidant, applying encapsulant, and curing the encapsulant. The resultant fuse of the preferred embodiment comprises a substrate, termination pads, conductive epoxy interconnects, a solder type fuse link, liquid deoxidant and encapsulant.

Abstract: An electric system of an electric vehicle including a main battery as a power supply, and a semiconductor power converter for driving a wheel driving motor. Impact destroying switches are inserted into connecting lines which connect a main battery to the semiconductor power converter, and into a connecting line connecting main battery block. Each impact destroying switch breaks its conduction by blasting an explosive in the switch in response to the impact due to a collision of the vehicle body. In case of an emergency such as a collision, since the main battery is instantaneously disconnected from the connecting lines by the switches, the connecting lines become free from the voltage. This makes it possible to prevent fire, and to cut off the vehicle body to save passengers.

Abstract: A thermally fused resistor arrangement wherein a resistor is electrically connected at one end to a first resistor terminal and at an opposite end to a second resistor terminal. A solder loop is provided to make the electrical connection between one end of the resistor and its corresponding resistor terminal. A portion of the solder loop is positioned in contact with an electrically insulated portion of the surface of the resistor, preferably corresponding to the hot spot of the resistor, and a thermally conductive medium is provided to thermally and mechanically attach the solder loop to the electrically insulated portion of the resistor surface. The portion of the solder loop thermally attached to the resistor is operable to melt when the temperature of the resistor increases to within a predefined temperature range, thereby electrically disconnecting the end of the resistor from its corresponding resistor terminal.

Abstract: A device for disconnecting the flow of current in the positive or impregnated battery cable of a motor vehicle has an electrically conductive plug-in connection that can be placed in the positive or impregnated battery cable in the form of a housing and a plug connector. The housing contains a gas generator of the kind used, for example, for belt tighteners. The gas generator is arranged in the housing in such a way that the propellant gas produced when the gas generator is ignited electrically separates the connector from the housing and this in turn interrupts the flow of current in the positive or impregnated battery cable. Consequently, a short circuit that might occur in the event of an accident and which could otherwise lead to damage of the cable tree and then set the vehicle on fire, is avoided in good time.

Abstract: An elongated electrical lead has a first part of a hard and brittle arc quenching metal integrally joined to an easily bendable second part of a ductile metal. The lead is used in a thermal cutoff with the first part being inside of the thermal cutoff housing and having an end portion defining an electrical contact. The second part of the lead extends outwardly from the thermal cutoff for connecting same in an electrical circuit.

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 chemically augmented electrical fuse is triggered using optical energy acquired as a result of the triggering of another chemically augmented fuse. Light energy created as a result of the detonation of the first chemically augmented fuse is conducted to an exothermic pellet of a second fuse. The light energy received at the second fuse is focused on the exothermic pellet by means of a lens. The focused light energy causes the detonation of the exothermic pellet in the second fuse thereby causing the interruption of current through that fuse.

Abstract: A car-borne electric cigar lighter includes a receptacle having a spring contact for receiving the heater element of the lighter for energization. A pair of spaced electrially conductive connecting plates form part of the electrical circuit to the spring contact. A circuit breakable electrically conductive spacer including a heat resistant, form-retaining resilient plate of an electrically insulating rubber, e.g., silicone rubber, penetrated between opposite surfaces with a thermally fusible, electrically conductive portion made from a low melting point metal, e.g., tin foils, to be in contact with the two connecting plates on both sides of the spacer forms an electrical connection between the plates through the tin foils. In case of overheating, the tin foils are melted down to open the electric circuit to the spring contact without losing the mechanical integrity of the spacer to serve as an insulator between the connecting plates.

Abstract: A device for holding a thermal cutoff device and a resistor in assembled relationship to each other in a housing and biasing the thermal cutoff device and the resistor into heat tansfer relationship with each other in the housing. Metal clips are attached to each housing half such that when the housing halves are mated, the clips are in opposing relationship to each other. Arcuate ends are formed on the clip such that when the opposing ones of the clips face each other in the housing, the arcuate ends substantially encircle one-half of the thermal cutoff device. Resilient fingers are formed on the other end of each of the clips such that when the opposing clips face each other, the resilient fingers grasp the resistor and pull it into engagement with the thermal cutout device for heat transfer relationship. The resilient fingers deflect sufficiently to allow resistors of different diameter to be used in the housing.

Abstract: Electrical switchgear apparatus comprises a base, a switching circuit element supported by the base and including at least one movable circuit element part, a thermal trip supported by the base for tripping motion in a given direction with respect to the movable circuit element part and a transmission device for imparting the tripping motion to the movable circuit element part, the transmission device comprising first and second members movable with respect to one another in the given direction to define a desired composite length for the transmission device in the given direction.

Abstract: Gold, copper, silver, palladium or aluminum and their alloys, but preferably gold or gold alloy, which may be in the form a wire, has deposited thereon or contained within the wire, a material such as metals or metal alloys which diffuse into the gold or into the other listed metals. With the passage of time and exposure to temperature the deposited metal or metal alloy continues to diffuse into the gold forming intermetallics with the gold and thereby causing the resistivity of the gold to increase and causing the gold to become progressively more brittle until such time as the gold wire ruptures at a stress point. At a given temperature the elapsed time until rupture takes place depends upon the metal or metal alloys deposited on or contained within the gold. Lead, indium, gallium, tin, bismuth and aluminum and the alloys of these metals diffuse into and form intermetallics with the gold.

Abstract: Methods and pressure transducers for measuring strain as a result of stress applied to a sample are disclosed. These pressure transducers include polymeric elements comprising a piezoresistive blend of a doped acetylene polymer and an elastomer.

Abstract: A method and device for driving a linearly movable component, wherein a pressurized fluid is generated by feeding a given volume of oxygen into a combustion space connected to a piston/cylinder configuration and feeding a given volume of fuel into the combustion space for each motion stroke of the piston/cylinder configuration beore the start of the motion stroke, the given volume of oxygen is sufficient for the combustion of the fuel, the given volume of fuel is sufficient for generating the pressurized fluid, the oxygen and fuel are ignited in the combustion space, and the pressurized fluid is feed into the piston/cylinder configuration for driving a piston of the piston/cylinder configuration and a linearly movable component connected to the piston.

Abstract: An electrical fuse adaptable for a wide range of current rating and response times. The fuse comprises a conductive element and an explosive charge, the latter shearing the conductive element at a predetermined temperature. In the disclosed embodiments, the explosive charge can be heated to the detonation temperature using a variety of auxiliary heat sources.

Abstract: An exothermically assisted electric fuse, having at least one exothermic body disposed in heat transfer relationship with at least a portion of each fusible element of the fuse, a triggering circuit for initiating an exothermic reaction in response to an overcurrent through the fuse, and a containment body partially enclosing the exothermic body for directing the heat energy released by the exothermic reaction. The containment body is disposed so as to confine and direct the heat energy in a direction which is substantially perpendicular to a plane containing the portion of the fusible element which is in heat transfer relationship with the exothermic body. In a preferred embodiment of such a fuse, the fusible element is wound around a support so that the fuse windings form the general shape of a cylinder, and the containment body is disposed so that the heat energy is directed in a radial direction with respect to the cylinder formed by the fuse windings.

Abstract: In an electrical fuse which serves for temperature limitation, which comprises a closed housing (1) and in which a spring mechanism (2,3,4) interrupts an electrical contact as soon as a fuse body (6) serving as a support for the spring mechanism liquefies and relieves the spring mechanism, the fuse body mainly consists of a saturated dicarboxylic acid containing 4 to 14 carbon atoms.

Abstract: An inductively compensated trigger conductor for use in a chemically augmented fuse, of the type in which current flow through the fuse generates a magnetic field, employs at least one loop of electrically conductive material to inductively couple the trigger conductor to the magnetic field of the fuse. This inductive coupling increases the electrical inductance of the trigger circuit, and allows the fuse to be constructed so that the current division between the fuse conductor and the trigger conductor is constantly proportional, or at least more nearly so. When employed in a fuse which also includes a non-magnetic fuse support structure, a trigger device, and a means for chemically augmenting the separation of the fuse conductor into more than one segment during current interruption, the trigger circuit of this invention provides triggering action which is responsive only to the level of current flowing through the fuse, and not to a high rate of rise of current.

Abstract: An explosively-assisted fuse is passively triggered (without electronics) by means of an auxiliary fuse in series with the main conductor. The auxiliary fuse provides a detonating voltage across a gap formed therein on melting in response to a fault current. The auxiliary fuse is configured to facilitate sizing for a variety of current loads with a standard fuse configuration.

Abstract: A delayed action switch embodied in a tubular casing adapted to be incorporated in a missile or a guided projectile. For example, the Redeye missile is activated by a soldier who keeps it against his shoulder. As he pulls the trigger, the missile takes off toward a specific target such as a tank, truck or the like, a distance of a few seconds away from the soldier. Should the missile drop near the soldier and explode, the soldier would be killed; but with the delay switch of this invention incorporated in the missile, it would be deactivated before it hits the ground. Consequently, the missile would be a "dud", a non functional device. In general, the switch of our invention includes, in succession within a tubular casing, a priming charge which is ignited when the missile is first propelled into the atmosphere, and which fires an ignition charge which in turn ignites a delay charge.

Abstract: Electrical resistance heating element including a number of metal strips arranged in a meander-like pattern. In the resistance metal strips, which are made from a non-expensive base sheet material like lead, there is incorporated at least one fuse which will operate if the heat transfer from a randomly placed area of critical size (a critical area) is substantially blocked. The fuse or fuses are preferably constituted by a lead/tin alloy rolled into intimate contact with the lead base material.

Abstract: An improved switch for a high-voltage device in which ignition of a power cartridge generates pressure at one end of an insulative piston to move the piston, located in a conductive member, into a passageway in an insulative liner, said piston moving a contact through the passageway and away from the conductive member to break an electrical interconnection between the conductive member and the movable contact,an insulative lip seal located in the bore between the power cartridge and the one end of the piston, the lip seal being movable with the piston and being conformally force-fit into the bore, andmeans limiting movement of the lip seal through the bore so that the lip seal remains in the bore after the switch is open restricting the flow of the ignition products of the power cartridge.

Abstract: An electrical switch includes an alternating series of first and second switch cells. Each first cell includes a first conductive member with a first bore and a first insulative member conformally located in the first bore and movable through the first bore. Each second cell includes a second insulative member with a second bore and a second conductive member conformally located in the second bore and movable through the second bore. The first and second bores have substantially the same cross-section. The cells are mounted end-to-end in the alternating series so that the bores align. Severable diaphragms electrically interconnect the second conductive member of each second cell to the first conductive member of the first cells adjacent to the second cell. The first insulative members and the second conductive members are simultaneously moved to simultaneously sever the diaphragms. A plurality of insulated gaps are thereby produced between the first and second conductive members of adjacent cells.

Abstract: A high-speed switch usable at high voltage includes a pair of contacts movable apart along a fixed line. When the contacts are normally interconnected, at least one of them contributes to the definition of an enclosed chamber. Pressurization of the chamber by the ignition of a power cartridge therein rapidly drives the contacts apart, forming a first gap between them. The first gap is electrically insulated and is shielded from the ignition products of the cartridge. Any arc forming in the first gap is constricted and subjected to arc-extinguishing gas. When the contacts are interconnected, a first one of them is electrically connected to a terminal. After the contacts move apart, a second gap forms between the first contact and the terminal. The second gap is electrically insulated and is shielded from the ignition products of the cartridge. A fuse may be connected in shunt with the contacts and the insulated gaps.

Abstract: A high voltage fuse comprises one or more fusible strips or wires (fusible elements) electrically connected between nonfusible external electrical connection means with at least one portion of the fusible element ("a rapid melting portion") being designed to melt open when the current exceeds a given value for a given period of time. The fuse further comprises exothermic material, disposed on electrically-conductive wire, which is placed adjacent to portions of the fusible element. Electric circuit connection means connect the electrically-conductive wire to electrically opposite sides of the rapid melting portion. The electrical circuit connection means provides for either parallel or series connection of the wire surrounded by the exothermic material.

Abstract: Apparatus is provided for automatically interrupting current in an electrical circuit before the first current peak which occurs after an excess current condition develops. The apparatus includes a main conductor in the current path which passes the current under normal operating conditions, and pyrotechnic charge means associated with the conductor at several spaced locations which segments the conductor when it is ignited. The charge means is ignited by a fuse link which senses the current and provides a rapid thermal response to excess current conditions, generating sufficient heat to ignite the charge means within a short period of time. A current limiting fuse element may be connected in parallel with the conductor for operation at higher voltages, if needed, and the entire apparatus, including the resistive sensing means, may be contained in a single housing.

Abstract: An improved switch for a high-voltage device in which ignition of a power cartridge moves an insulative piston located in a conductive member, into a passageway formed in an insulative liner, said piston moving a contact through the passageway and away from the conductive member to break an electrical interconnection between the conductive member and the movable contact and to form a gap therebetween, thereby opening the switch; the bore and the passageway being aligned,the piston being made of a material which is more rigid and less easy to deform than the material of the liner upon the application, at a given rate, of a given load, andthe size of the piston being greater than the size of the passageway.

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 high speed high voltage electrical switch opens a current path in which the switch is included. The switch includes first and second normally electrically interconnected contacts which normally carry current in the current path. The contacts are relatively movable along a fixed line of direction. When the contacts move apart, the electrical interconnection therebetween is broken to open the first current path. A piston carried by the second contact defines an enclosed chamber in conjunction with the first contact when the contacts are interconnected. A power cartridge or the like selectively pressurizes the chamber to rapidly drive the contacts apart. The piston enhances the action of the power cartridge by ensuring that pressure increases caused thereby are effected to drive the contacts apart. The piston may be configured to ensure positive sealing engagement with the walls of a cylinder through which the piston and the second contact move following the ignition of the power cartridge.

Abstract: A high-voltage, blast-actuated power switch is disclosed in which non-arcing edges are formed on a bridge conductor when the conductor is blasted. Upon blasting, the bridge conductor bends forming edges having a large radius of curvature. When the bridge conductor is blasted, an element of the bridge conductor moves in the axial direction away from the other element of the bridge conductor, thereby increasing the separation between bridge conductor elements. The axially movable bridge conductor is held in its new axial position causing the bridge conductor elements to remain separated.

Abstract: A high current switch includes first and second contact plates, each having a contact surface. The contact plates are moved between a closed position with the contact surfaces in contact and an open position with the contact surfaces separated. An electric bridge has opposite ends connected to the contact plates and spans the contact surfaces. During opening of the switch, the electric bridge, in the form of a fuse, remains integral and provides a secondary electrical connection between the contact surfaces, thus preventing arcing therebetween. Upon complete opening of the switch, the electrical bridge ruptures.

Abstract: A switch is provided for use in controlling currents associated with power line faults. The switch includes a housing with a pair of relatively movable electrodes opened and closed by means of chemical propellants. In the preferred form, one electrode comprises a movable contact slidably disposed in a support cylinder within the housing and the other electrode is fixed. The sliding contact is movable into a closed position in which the electrodes are in mutual contact. A first chemical propellant charge disposed in the support cylinder drives the contact into the closed position. A chamber for holding dielectric fluid is disposed in the housing and extends through an opening in the fixed electrode. A second propellant charge is located behind a piston in the chamber. When in the closed position, the contact blocks and closes the opening in the electrode, thus closing the chamber.

Abstract: A thermal switch for automatically opening a circuit when the ambient temperature exceeds a predetermined level is disclosed which utilizes a sensing pellet formed of an organic-glass bead mixture. The organic-glass bead pellet retains a pair of leads in contact with each other when the ambient temperature is below the melting temperature of the organic material. The addition of the glass beads to the temperature sensing pellet allows the compressive strength that is needed to hold the leads together to be more reliably controlled. In the process of combining the organic material and the glass beads, to form the pellet, the organic material is first melted so as to flow around the beads. Manufacture of the thermal-sensing pellet in this manner eliminates the voids which occur in the pressed organic pellets that are conventionally used in thermal sensing devices.

Abstract: A high intensity arc discharge lamp has an arc tube the emission of which includes some harmful UV radiation. An outer envelope surrounds the arc tube and substantially blocks the harmful UV radiation. The lamp includes means to render the arc tube inoperative when the outer envelope becomes cracked or punctured sufficiently to admit air therewithin, the means including a pyrophoric material to initiate combustion of a current carrying portion of the lamp circuit.

Abstract: An explosively activated current interrupter is provided for use in a fault current limiting system employing a plurality of such interrupters. Each interrupter includes an automatic switching system for sequentially installing each of a plurality of the interrupters on a power line. A conductive member in the interrupter housing conducts current carried by the power line. An explosive charge in the housing breaks the conductive member into a plurality of separated portions upon detonation, thereby interrupting the power line current. A switch opened and closed by means of explosive gas pressure alternately installs and removes the interrupter from the power line. Each interrupter is connected by a gas conduit to the next sequential interrupter to be detonated. Upon detonation of one interrupter, a portion of the explosion gases are transferred by the conduit to the next interrupter, operating the switch to install the next interrupter on the power line after an appropriate delay.

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 a predetermined temperature to form an electrically conductive path between the electrodes, regardless of the orientation of the device. The first electrode is concave and the second electrode extends into the concavity formed by the first electrode.