TH40480A - Improvement of the arrangement mechanism to cut off the heat. - Google Patents

Abstract

DC60 (14/05/46) A leadless varistor, which is stripped off, is inserted into a slot created in the printed circuit board (PCB) 20. The printed circuit board (PCB) has the usual circuit tracks 22, 24, 26. The electrical and physical connection between the printed circuit board (PCB) 20 and the varistor is achieved by using solder 28. When the varistor overheats to the point where its temperature exceeds a predetermined temperature, the solder melts and the varistor is separated from the printed circuit board (PCB) 20. A sheet spring 30, which is weighted when the varistor is inserted into the slot, pushes the varistor out of the slot when the solder 28 melts. Conversely, when the solder 28 melts, gravity pushes the varistor out. A varistor, without leads, is removed from the printed circuit board (PCB) and inserted into a slot created in the PCB. The PCB has its usual circuit tracks (22, 24, 26). The electrical and physical connection between the PCB and the varistor is achieved using solder (28). When the varistor overheats, exceeding a predetermined temperature, the solder melts and the varistor is detached from the PCB. A sheet spring (30), weighted down when the varistor is inserted into the slot, pushes the varistor out of the slot as the solder melts. Conversely, when the solder melts, gravity causes the varistor to detach from the PCB.

Claims (13)

1. The thermal clamping mechanism consists of a varistor mounted on a specially designed printed circuit board (PCB). The varistor comprises a voltage-dependent resistor (RW) disc sandwiched between a pair of conductive metal discs. The PCB houses a mounting mechanism for the varistor, consisting of an opening through the PCB to accommodate the sliding varistor with its disc's central axis parallel to the PCB plane; guide tracks on the PCB leading to each side of the opening adjacent to the RW discs where the varistor is mounted; and a thermally sensitive clamping mechanism providing electrical contact between the discs and the tracks. The thermally sensitive clamping mechanism is adjusted to hold the varistor in the opening and releases it when the clamping mechanism reaches a predetermined temperature. The mounting mechanism also includes a counterweight mechanism to push the varistor out of the opening. 2. The arrangement mechanism according to claim 1, where the metal disc has a diameter less than the diameter of the resistor disc. 3. The arrangement mechanism according to claim 1, where the heat-sensitive fixing mechanism is solder with a predetermined melting point. 4. The arrangement mechanism according to claim 3, in which the guide tracks on the circuit board have a predetermined geometric shape to optimize the amount of available heat-sensitive fixing mechanisms and their melting characteristics. 5. The arrangement mechanism according to claim 1 contains independent tracks on the circuit board connected to at least one side of a varistor for use in indicator circuits. 6. The counterbalancing mechanism pursuant to claim 1, where the counterweight mechanism is gravity. 7. The arrangement mechanism according to claim 1, where the counterbalancing mechanism is flexible. 8. The arrangement mechanism, based on claim 7, where a flexible counterweight mechanism creates a portion of the switch/contact used to indicate the normal operation of the circuit. 9. The alignment mechanism according to claim 7, in which the elastic counterweight mechanism operates the mechanical alignment mechanism to provide a visible indication of the operating condition of the circuit. 10. A mechanism arranged according to claim 7, in which the movement of a varistor under the action of a counterweight mechanism operates a switch with contacts or a mechanical indicator to indicate the operating state of the circuit. 11. The arrangement mechanism, which internally contains a number of heat-cutting mechanisms as per claim 7 provided in the circuit, and in which visible indicators and flexible counterweight mechanisms are assembled. 12. The mechanism pursuant to claim 1 shall be arranged to receive a varistor released by the fixing mechanism. 13. The arrangement mechanism according to claim 1 in which those parts of the varistor not in contact with the mounting mechanism are coated to protect them from environmental factors.