Abstract: A pyrotechnic cut-off device includes: a pyrotechnic igniter, a conductive portion and a movable piston, the piston being able to be displaced in a cavity along a direction of displacement following the actuation of the pyrotechnic igniter between a first position of passage of the current in the conductive portion and a second position of cut-off of the current, wherein the piston defines a first sealing portion having a narrowing of section along the direction of displacement, and the cavity has a wall defining a second sealing portion which extends on either side of the conductive portion and which has a narrowing of section along the direction of displacement, the first sealing portion being in contact with the second sealing portion along a contact surface extending on either side of the conductive portion when the piston is in the second position.

Abstract: An electronic assembly contains a circuit board having a current-conducting current path with two mutually spaced-apart current path ends that form an interruption point and a contact clip bridging the interruption point. The contact clip is manufactured without a preload, as a thermal fuse. The contact clip has a multiple bent, open clip loop and a contact limb making contact with both mutually spaced-apart current path ends using solder. The contact clip further has a fixing limb with a limb end seated in a circuit board opening. The limb end of the fixing limb is oversized relative to a circuit board opening, and a deformation being imparted to the contact clip, with an internal preload being generated.

Abstract: A liquid metal-based information identification system includes a recognizer and a smart tag. The smart tag is configured to record environment information of an environment where an article is located through a sensor, and to send the environment information to the recognizer via a flexible circuit. The flexible circuit is internally used by the smart tag and comprises a circuit made of a liquid metal provided with a microfluidic channel including a vacuum chamber. When the liquid metal is in a phase transition, the liquid metal enters the microfluidic channel in such a manner that the circuit made of the liquid metal is short-circuited or disconnected. The recognizer is configured to receive and analyze the environment information, and to download first information of an article production link to the smart tag.

Abstract: Approaches herein provided surface mounted devices each configured as a stand-alone component suitable for attachment to a substrate such as a printed circuit board (PCB). In some embodiments, a method includes forming a base housing, coupling an electronic component to the base housing, and forming a cover over the electronic component, wherein the cover is coupled to the base housing. The electronic component may include a fusible link/element extending between terminals, the terminals wrapped around an exterior of base housing. The device may then be coupled to the PCB, for example, by attaching the terminals to an upper surface of the PCB.

Abstract: An activatable thermal fuse includes a first electrical terminal, a second electrical terminal, and an electrically conductive bridge element having a first electric contact with the first electrical terminal and a second electric contact with the second electrical terminal. At least a part of the bridge element is displaceable from a first position in which the first contact is established to a second position in which the first contact is opened, and a thermally sensitive member releases the part when exposed to a predetermined temperature value. An activating element blocks displacement of the part from the first position, in a first position of the activating element, and enables the displacement of the part in a second position of the activating element. A method of manufacturing a printed circuit board, a method of monitoring, and an electronic circuit including the thermal fuse are also provided.

Abstract: An electronic assembly contains a circuit board having a current-conducting current path with two mutually spaced-apart current path ends that form an interruption point and a contact clip bridging the interruption point. The contact clip is manufactured without a preload, as a thermal fuse. The contact clip has a multiple bent, open clip loop and a contact limb making contact with both mutually spaced-apart current path ends using solder. The contact clip further has a fixing limb with a limb end seated in a circuit board opening. The limb end of the fixing limb is oversized relative to a circuit board opening, and a deformation being imparted to the contact clip, with an internal preload being generated.

Abstract: A thin film fuse is formed by two substantially planar conductors, separated from each other by a thin gap. The conductors and gap are over-coated with a thin, conductive material having a surface tension when melted, great enough to pull the conductive material out of the gap.

Abstract: Described is a fuse for an electrical circuit, comprising two contact arms, each having at least one connecting pin for inserting into a hole of a printed circuit board, and a spring which connects the two contact arms in an electrically conductive manner. According to this disclosure, it is provided that the spring is fastened to at least one of the two contact arms by means of a fastening means that loses its strength at a trigger temperature of the fuse, wherein the fuse is formed in such a manner that by inserting the connecting pins into holes of a printed circuit board, the spring is loaded such that the spring lifts from the at least one contact arm by spring force as soon as the fastening means loses its strength due to overheating. Moreover, a printed circuit board comprising such a fuse is described.

Abstract: A thermal cut-off device can include a case, a first electrically conductive lead disposed at a first end of the case, a thermally responsive pellet housed within the case, a second electrically conductive lead disposed at a second end of the case and having a distal end including a contact surface, an electrically conductive contact disposed between the pellet and the second lead, a first biasing member disposed between the pellet and the contact, and a second biasing member disposed between the contact and the second end of the case.

Abstract: A protective device including a substrate, a conductive section and a bridge element is provided. The conductive section is supported by the substrate, wherein the conductive section comprises a metal element electrically connected between first and second electrodes. The metal element serves as a sacrificial structure having a melting point lower than that of the first and second electrodes. The bridge element spans across the metal element in a direction across direction of current flow in the metal element, wherein the bridge element facilitates breaking of the metal element upon melting.

Abstract: A fuse includes an upper shell, a lower shell and a cavity formed by the upper shell and the lower shell; first and second conductors which are respectively disposed between the upper shell and the lower shell. The first ends of each conductors are disposed in the cavity and form a clearance. The second ends of the conductors extend out from the cavity. A conductive bar is welded to the first and second conductors to form a first weld line and a second weld line.

Abstract: A temperature fuse protection device uses a hot melt metal to rivet for connecting two terminals in the circuit that are separated for making the two terminals electrically-connected and the circuit complete. There is a spacing in between the two free ends of the two terminals when no external force is being imposed. When an electric overloading or high circuit temperature event occurs, the hot melt metal would be heated to melt and break, which would then make the free ends of the two terminals to be disconnected, and therefore, the circuit will be at “OFF” status.

Abstract: A fail-safe assembly for an electronic or electrical component, device, system or apparatus with coacting operatively associated contacts has an impact member, normally maintained in a stressed and disengaged portion, and a meltable or fusible member for holding and for actuating the release of the impact member to guard against the danger of fire and damage due to current overload and/or unacceptable increases in the temperature in the current-carrying members for operating the coacting contacts or the ambient temperature for any reason and assures, on melting of the meltable or fusible member, that there are sufficient forces created to open and maintain the coacting contacts in the open position.

Abstract: A bus bar is connected between a battery post and a stud bolt to which an electric power supply wire is connected. An opening is provided in a housing in which an explosive sealing portion is accommodated. Just before the opening, a broken portion of the bus bar is provided. In the broken portion, a recess portion is formed, and this portion of the broken portion is thin. On both sides of the broken portion, a cutout portions are formed. In case of emergency, electric current generates in a trigger wire, and an explosive in the explosive sealing portion is exploded. An explosive force is directed to the opening of the housing, and the broken portion located just before the opening receives the explosive force forward. Due to the foregoing, the recess portion is broken and both broken pieces are bent at the cutout portions and opened being separated from each other. In this way, an electric power supply circuit is shut off.

Abstract: The connection structure of a circuit protection element for securely connecting at least two lead terminals of the circuit protection element to a circuit board includes terminal connection elongated holes each provided in the circuit board for connecting the lead terminals to the circuit board by soldering. The circuit board is positioned in such a way that the elongated direction of the elongated terminal connection hole is positioned in a downward direction. When an abnormal current is applied to the circuit, or when the circuit protection element fails to heat itself up to a high temperature, the solder melts. Thereby, the lead terminals easily disengage from the terminal connection holes so that the circuit protection element falls freely from the circuit board. Thus, the circuit is surely cut off easily.

Abstract: A dual-functional fuse unit, which is responsive to an electric current and an ambient temperature, contains a current sensing fuse and a temperature sensing fuse element. The current sensing fuse is serially connected with and between lead terminals of the fuse unit directly or through an intermediate conductor member. The current sensing fuse or the intermediate conductor member is urged but kept from moving when the temperature sensing fuse element is in a solid state. When the fuse element melts at a specified ambient temperature the urged current sensing fuse or the intermediate conductor member is displaced by the urging force so that the lead terminals are electrically disconnected from each other. In other embodiment, an urged cutter member in the case is normally kept from moving but is driven to sever the element of the current temperature fuse when the temperature sensing fuse element melts at a specified ambient temperature.

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: An overtemperature protection assembly with a mount, a solder terminal and a bridging connector. The mount is a block of ceramic material with a slot extending therethrough. The solder terminal has an end that is located in the slot and forms a frictional connection therein. The bridging connector has a busing terminal and a spring contact. The busing terminal has an end that is located in the slot. The spring contact has a first end connected to the busing terminal and a second end that is deflected towards the solder terminal and soldered thereto. If the solder connecting the second end of the spring contact to the solder terminal melts from excessive heat, the spring contact deflects away from the solder terminal thereby breaking electrical connection between the solder terminal and the busing terminal.

Abstract: An electronic device integrally formed with an automatic switching-off structure for protecting the device from overheating. At least one conducting lead of the electronic device is mechanically and electrically connected to its corresponding electrode by means of a solder column having desired melting point, with an appropriate spacing being kept between the conducting lead and the electrode. The coating layer of the electronic device is formed by a material such as epoxy resin which will soften and release a gaseous substance when heated to a temperature near its ignition point. When the temperature of the device exceeds the melting point of the solder, the solder column melts to break the electrical circuit and prevent overheating of the device. If the electronic device per se has higher working temperature, the coating layer is formed by a material having a higher ignition point such as silicon resin or silicon rubber which will not soften and expand when heated to a temperature near its ignition point.

Abstract: A self-configuring photoelectric control circuit for controlling operation of a load based on ambient light. The photocontrol circuit comprises a photocell responsive to ambient light, a heating resistor connected to the photocell, a bimetallic element in proximity to the heating resistor and movable in response to generation of heat from the heating resistor. A switch is operated by the bimetallic element and is connected between an input connected to a power source and an output connected to the load. A series resistor is connected to the heating resistor and a shunt is connected across the series resistor to provide a current bypass around the series resistor for operation with a low voltage power source, for instance 120 volts. The shunt is maintained in a flexed condition to form the bypass and a connection of the shunt across the series resistor is formed of a meltable material.

Abstract: A heater includes a base plate, and a resistor, extending in a longitudinal direction of the base plate, for generating heat when a power supply is applied thereto. A recess, such as a hole or groove, is formed in the base plate in a longitudinal portion of the resistor, to bias the base plate to break at the longitudinal portion and to open a circuit including the power supply and the resistor, to safely prevent overheating or smoking of the heater.

Abstract: An apparatus for protecting circuitry includes a heat actuated fuse which opens at a predetermined temperature and a resistive device disposed proximate the fuse for heating the fuse in response to an electrical current passed through the device. The fuse includes first and second electrodes bridged by a solder link which melts at the predetermined temperature and retreats to the electrodes. A quantity of flux-containing material is disposed on the link to promote rapid and complete retreat of the solder when the fuse is actuated.

Abstract: A tubular electric resistance heater includes a tubular sheath enclosing an electric heater coil. As protective overheat safety device is provided at an end of the sheath and includes an electrically conductive tube disposed in a cavity in the end of the sheath and having a closed end electrically connected to the heater coil. A rod-shaped member made of a thermally deformable material extends through the tube from the closed and projects out of the other end of the tube into activating engagement with a normally closed switch located externally of the tubular sheath and electrically connected in series with the tube and thereby the heater coil. Excessive heater coil temperatures cause the rod-shaped member to deform and actuate the switch to its open position to deenergize the heater coil. The rod-shaped member may be made to a memory-alloy or a plastic which changes its structure, e.g., shrinks, or melts at a certain temperature.

Abstract: A thermal and current sensing switch which brakes an associated electric circuit when an overcurrent is supplied to the electric circuit or the temperature of the electric apparatus rises beyond a predetermined temperature. The thermal and current sensing switch comprises a housing, fixed conductors fixed to the housing with the base ends thereof extended within the housing; a current fuse placed in the housing with the opposite terminals thereof in contact with the fixed conductors; a first spring biasing the current fuse away from the fixed conductors, a second spring pressing the current fuse against the fixed conductors against the force of the first spring, and a temperature sensing element provided between the housing and the second spring. When the ambient temperature rises beyond a predetermined temperature, the temperature sensing element reduces the force of the second spring to allow the first spring to separate the current fuse from the fixed conductors to break the electric circuit.

Abstract: A thermal cutoff of the type including an electrically conductive housing and an electrical lead having dielectric material sealingly interposed therebetween. Indicia is located on the lead such that when the dielectric material extends to or beyond the indicia, the distance between the housing and the lead along the dielectric material satisfies the minimum creepage distance required between two metal surfaces of opposite polarity.

Abstract: A normally closed electrical switch mechanism having fixed and movable switch assemblies, a spring assembly urging the movable switch assembly away from engagement with the fixed switch assembly to thereby open the switch, a latch member normally securing the movable switch assembly in its position of engagement with the fixed switch assembly, and a mechanism responsive to a predetermined condition external to the switch mechanism for moving the latch member so as to allow the switch to open, is improved in the following manner. A member made of thermoplastic material is positioned between the latch member and the movable switch assembly. The thermoplastic material of that member is then responsive to an overheated condition of the internal switch circuitry for losing its structural rigidity so as to release the movable switch assembly and thereby permit the spring assembly to open the switch even though the latch member remains in place.

Abstract: A temperature safety device includes an electrically insulative support, electrical connectors extending outwardly of the support, first and second contact elements having first fixed ends connected with the electrical connectors and free ends engageable to provide a switch within the support in series circuit with the electrical connectors. A melt material insert adapted for heat transfer relation with apparatus being protected by the safety device, is included and a mechanical force transfer element is disposed between the insert and the second contact element, applying force thereto to effect closure of the contact elements in part attributable to counter-forces exerted by the contact elements.

Abstract: A thermally responsive control especially for a clothes iron combines an adjustable, temperature-regulating thermostat and an over-temperature control for limiting maximum temperature levels on a plastic mounting bracket where the over-temperature control also protects the mounting bracket against damage from overheating.

Abstract: A thermally actuated latch for electrical circuits is permanently operative for completing an electrical circuit upon exposure to a predetermined elevated temperature. The latch includes a fixed contact, a movable contact arm which is biased toward the fixed contact, a movable contact on the movable contact arm, and a deformable pellet. The deformable pellet communicates with the movable contact arm through a communicator disc to normally maintain the movable contact in spaced relation with the fixed contact. The pellet is deformable to a disposition of reduced profile upon exposure to a predetermined elevated temperature to allow the movable contact to be resiliently moved into engagement with the fixed contact in order to complete an electrical circuit connected to the latch.

Abstract: A thermal fuse has an insulative tubular case, two lead wires, a lead wire separating tool, an electrode plate consisting of two conductive metal plates deposited with fusible alloy which fuses at a preset temperature and an elastic body which presses the electrode plate. When the fusible alloy fuses at a preset temperature, the elastic body is released from compression and its top end portion is inserted in a cavity of the lead wire separating tool so that one end of each of the conductive metal plates is released from contact with the lead wire and the electric circuit between the lead wires is opened.

Abstract: A thermostatically controlled electric flatiron having a heater circuit of sufficient wattage to achieve abnormally high soleplate temperatures on continuous operation is provided with an overtemperature protection assembly for opening the heater circuit before damaging high soleplate temperature occurs on thermostat failure. The assembly includes first and second members connected in the heater circuit and electrically isolated from the soleplate and each other bridged by a third spring-biased circuit member to complete the heater circuit. A slug of eutectic alloy forms a fusible joint bonding the third member intermediate its ends to one of the first and second members to hold the third member against the spring bias in circuit completing contact with the first and second.

Abstract: A thermal cut-off device comprises a casing and a cover therefor both made of a highly heat conductive electrically insulating material such as ceramic. A pair of lead wires protrude from opposite ends of the casings with the other ends of the wires being electrically connected to an electrical assembly within the casing. The electrical assembly comprises a leaf spring, a conductive fixed terminal and a plastic mass for biasing the leaf spring so as to contact the fixed terminal during closed circuit condition. A helical spring in the casing stabilizes the leaf spring upon its release when the plastic mass melts due to overheating.

Abstract: A fuse for responding to external temperatures to interrupt an electrical circuit, for example for interrupting a telephone battery feed in response to the temperature of a battery feed resistor, comprises a substrate carrying a pair of electrodes defining a gap between them. A fuse link, for example a gold strip, extends across the gap to interconnect the electrodes electrically. A film of solder overlies the fuse link and overlaps at least partly at least one of the electrodes. The fuse link is soluble in the molten solder so when the temperature of the solder paste exceeds its melting point, it melts, dissolves the fuse link, and retreats from the gap to sever the electrical connection between the electrodes.The fuse and a resistor whose temperature is to be detected, may be provided on a single substrate.

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: Two wire leads project from opposite ends of a dielectric housing having a sealed chamber containing a fusible metal alloy link, which operatively connects the wire leads electrically to one another. A flexible, pre-loaded, dielectric spring element in the chamber engages and exerts upon the link a predetermined stress, which is operative to cause the link suddenly to fail and interrupt the connection between the leads, when the ambient temperature of the link exceeds a predetermined temperature range. In one embodiment the two wire leads project into the chamber and have spaced, confronting ends interconnected by the link, one side of which is held under compressive stress by the spring element.

Abstract: A circuit interrupting device responsive to externally generated heat and method of manufacture of such device. The device includes a pair of spaced, coaxially aligned leads each entering a thermally conductive housing from an opposite end. The inserted ends of the coaxially aligned leads are bridged by a conductive member comprising the tail of a conical spring which surrounds one of the leads and is secured at a corresponding end of the housing. The circuit-completing spring tail is secured by fusible material to the inserted ends of each of the spaced-apart leads. In a normal, closed circuit condition, the spring is under tension. Upon heating, the fusible material softens, allowing the spring tail to break away from the inserted ends of the spaced-apart leads, the retracting force of the conical spring, pulling the spring tail from the other one of the leads to open the circuit.

Abstract: The present invention discloses an electric safety device in which a fuse element adapted to break a circuit upon passage of an overcurrent and a circuit-breaking conductive member of the heat-sensitive type for preventing overheat are housed in one vessel and are electrically connected to each other, so that the circuit of an electrical appliance can be broken with respect to both overcurrent and overheat.

Abstract: A thermal cut-off fuse for breaking electric continuity between two lead wires, which utilizes melting and voluminal expansion of a temperature-sensitive member in a sealed state at a prescribed temperature.

Abstract: A thermal cut-off device is disclosed in which a first axial lead extends through an insulating member at one end of the device and a second axial lead contacts and extends through a conductive cylindrical housing at the other end of the device. A domed electrical contact cup is used in one embodiment to make electrical connection between the insulated lead and the outer metallic housing, and this electrical connection is maintained by a coiled helical spring. One end of the coiled spring is larger in diameter than the other end. The large diameter end is in engagement with the end of the conductive housing through which the second axial lead projects, while the smaller end of the conductive spring is in engagement with the insulated first axial lead, either directly or through the domed contact cup.

Abstract: The device described herein is useful in applications which formerly required both a thermal cut-off device and an electrical fuse. This device will open an electrical circuit in response to either an increase in ambient temperature or an increase in electrical current. A bracket is provided to support a radial lead thermal cut-off device. The bracket is of a general C-shaped configuration and has an extending lead bar that is crimped into electrical engagement with an input lead, and one radial lead of the thermal cut-off device is crimped into electrical engagement with the second input lead. A helical conductive coil has one end welded or otherwise secured to the C-shaped bracket, and the second lead of the thermal cut-off device is crimped to the other end of the helical coil which is positioned over the thermal cut-off device so as to surround it. Thus, an ambient temperature rise may cause the thermal cut-off device to open the electrical circuit; or alternately the heat generated by the I.sup.

Abstract: A thermal cut-off fuse of the class wherein the electric continuity between electrodes disposed inside a housing is maintained by conductor means at normal service temperatures and broken by the conductor means being fractured when the ambient temperature reaches a fixed level is improved by having the conductor means made of a metal capable of liquefying before the ambient temperature reaches the fixed level mentioned above and providing a thermal pellet faithfully fusible at the fixed level of temperature for the purpose of supporting in position the conductor means serving to maintain the electric continuity between the electrodes at normal service temperatures and thereby allowing the electric continuity between the electrodes to be broken at the fixed level of temperature by the thermal pellet being melted and deprived of its role of supporting the conductor means.

Abstract: A switch device utilizing independently acting biasing members to position a conductor to close a circuit between a pair of leads and maintain such closed circuit until a switch activating member such as a meltable pellet reaches a circuit opening state whereupon further independent biasing action causes the conductor member to assume a circuit open position.

Abstract: A collapsible pellet thermal limiter construction having an electrical switching unit that changes its condition when the pellet melts by being heated to a certain temperature for the particular pellet and having an epoxy material sealing one end of the casing of the construction. A filler material is disposed in the epoxy material and is in the order of approximately 4% to approximately 6% by weight of the epoxy material when the pellet has a particular melting temperature other than approximately 208.degree., 244.degree., 298.degree. F. or 358.degree. F.

Abstract: To detect and record the highest operating temperature range which occurs in an engine, transmission, implement hydraulic system or the like during an extended period of time, an indicator device is adapted to be mounted in thermal contact with a liquid coolant flow, lubricant flow or the like of the apparatus. The device has a housing containing a plurality of electrical resistor segments connected in series between an external electrode and the housing. A plurality of temperature-sensitive switches are arranged to short out successive ones of the resistor segments upon the occurrence of successively higher predetermined temperatures.

Abstract: A sensitive fuse for fire alarms comprising an extremely thin heat collector disk of nickel or brass nickel plated material. A pair of phenolic resin copper laminated attachment strips are soldered to the disk to form a unitary fuse. One attachment strip is permanently soldered to the disk and the other strip is attached to the disk with a eutectic solder which is formulated to melt at a low, predetermined temperature. The phenolic resin end of each strip has a punched hole for attaching the fuse assembly to alarm valve lever arms. The thinness of the heat collector disk results in rapid transfer of heat to melt the eutectic solder. The phenolic portions of the attachment strips serve to insulate the heat sensitive portions of the fuse assembly from the remainder of the alarm device to increase sensitivity.

Abstract: A thermal switch for automatically opening a circuit when the ambient temperature is increased to a predetermined level. A pair of conductor wires are arranged in side by side fashion with extremities extending in the same direction. A spring portion is included in at least one of the conductor wires to provide stored energy when the spring is biased into electrical contact with each other. A localized contact region is included in the conductor wire in the region below the spring portion. The extremities, contact region, and spring being encapsulated with a heat fusible material which biases the conductor wires into contact with each other and which is coated with a rigid insulating material to retain the conductor wires electrically insulated from each other except at the contact region.

Abstract: A thermal switch for automatically opening a circuit when the ambient temperature is increased to a predetermined level. A pair of conductor wires are arranged in side by side fashion with extremities extending in the same direction. A spring portion is included in at least one of the conductor wires to provide stored energy when the spring is biased into electrical contact with each other. A localized contact region is included in the conductor wire in the region below the spring portion but spaced upwardly from the associated extremities to create a lever arm. The extremities, contact region, lever arm and spring being encapsulated with a heat fusible material which biases the conductor wires into contact with each other and which is coated with a rigid insulating material to retain the conductor wires electrically insulated from each other except at the contact region.

Abstract: A thermal switch for automatically opening a circuit when the ambient temperature is increased to a predetermined level. A pair of conductor wires are arranged in side by side fashion with extremities extending in the same direction. A first spring portion is included in at least one of the conductor wires to provide stored energy when the spring is biased into electrical contact with each other. A localized contact region is included in the conductor wire in the region below the first spring portion. A second spring portion is also included in the conductor wire between the first spring and the associated extremity of the wire. The extremities, contact region, and spring regions being encapsulated with a heat fusible material which biases the conductor wires into contact with each other in a preloaded condition. A coating of rigid insulating material, retaining the conductor wires electrically insulated from each other except at the contact region, is provided over the heat fusible material.

Abstract: A collapsible pellet thermal limiter construction having an electrical switching unit that changes its condition when the pellet melts by being heated to a certain temperature for the particular pellet and having an epoxy material sealing one end of the casing of the construction. A filler material is disposed in the epoxy material and is in the order of approximately 4% to approximately 6% by weight of the epoxy material when the pellet has a particular melting temperature other than approximately 208.degree. F., 244.degree. F., 298.degree. F. or 358.degree. F.