# US 2013/0278376 A1 · RF Thermal Fuse > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0278376 A1 - Document ID: US20130278376A1 - Status: Published application - Kind: A1 - Application number: 13/869,653 - Filed: 2013-04-24 - Published: 2013-10-24 - Earliest claimed: 2012-04-24 - Assignees: Andrew Corporation - Applicants: Andrew LLC - Inventors: Frantisek Hrnicko; Vaclav Volf; Libor Strachon; Thomas Kummetz; Stefan Eisenwinter; Matthew Thomas Melester; Jürgen Struller; Gabriel Toth - Web page: https://patentgrep.com/patent/US20130278376A1 ## CPC - H01H 37/52: actuated due to deflection of bimetallic element - H01H 37/36: actuated due to expansion or contraction of a fluid with or without vaporisation (the fluid forming a contact of the switch H01H29/04, H01H29/30) - H01H 37/46: actuated due to expansion or contraction of a solid (deflection of a bimetallic element H01H37/52) - H01H 37/761: {with a fusible element forming part of the switched circuit (H01H37/767 takes precedence)} - H01H 37/767: {Normally open} - H01H 79/00: Protective switches in which excess current causes the closing of contacts, e.g. for short-circuiting the apparatus to be protected {(H01H39/004 takes precedence)} - H04W 52/04: Transmission power control [TPC] - H01H 2037/762: {using a spring for opening the circuit when the fusible element melts} - H04W 88/08: Access point devices - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Certain aspects are directed to a thermal fuse for preventing overheating of RF devices in a telecommunication system. The RF thermal fuse includes a body, a conductive bolt, and a driving mechanism. The body can be positioned on a transmission line between an RF signal source and an RF device. The conductive bolt is positioned in the body. The conductive bolt has a length sufficient to provide impedance at a point of protection on the transmission line in response to the conductive bolt contacting a live conductor of the transmission line. The impedance is sufficient to reflect a portion of the incident power of an RF signal from the RF source. The driving mechanism can cause the conductive bolt to contact the live conductor in response to a temperature at or near the point of protection exceeding a threshold temperature. ## Claims ### Claim 1 An RF thermal fuse comprising: a body adapted to be positioned on a transmission line between an RF signal source and an RF device; a conductive bolt positioned in the body, the conductive bolt having a length sufficient to provide an impedance at a point of protection on the transmission line in response to the conductive bolt contacting a live conductor of the transmission line, wherein the impedance is configured to reflect a portion of the incident power of an RF signal from the RF signal source; and a driving mechanism configured to cause the conductive bolt to contact the live conductor in response to a temperature at or near the point of protection exceeding a threshold temperature. ### Claim 2 (depends on 1) The RF thermal fuse of claim 1, wherein the driving mechanism is irreversible. ### Claim 3 (depends on 2) The RF thermal fuse of claim 2, wherein the driving mechanism comprises: a spring adapted to apply a force to the conductive bolt in a direction toward the live conductor; and a solder adapted to resist the force applied to the conductive bolt, wherein the solder comprises a soldering material having a melting temperature equal to the threshold temperature. ### Claim 4 (depends on 1) The RF thermal fuse of claim 1, wherein the driving mechanism is reversible. ### Claim 5 (depends on 4) The RF thermal fuse of claim 4, wherein the driving mechanism comprises a bimetal driving mechanism. ### Claim 6 (depends on 4) The RF thermal fuse of claim 4, wherein the driving mechanism comprises a chamber enclosing a gas or liquid, wherein the gas or the liquid is expandable such that the gas or the liquid applies pressure to the conductive bolt in response to the threshold temperature. ### Claim 7 (depends on 4) The RF thermal fuse of claim 4, wherein the driving mechanism comprises an electromagnet configured to oppose a force applied by a spring to the conductive bolt in a direction toward the live conductor, the electromagnet configured to oppose the force in response to the electromagnet receiving a current from the RF device. ### Claim 8 (depends on 4) The RF thermal fuse of claim 4, wherein the driving mechanism comprises a shape memory alloy spring mechanism. ### Claim 9 (depends on 1) The RF thermal fuse of claim 1, further comprising a dielectric material positioned at a first end of the conductive bolt opposite a second end of the conductive bolt adapted to contact the live conductor. ### Claim 10 A thermal protection system comprising: a plurality of RF thermal fuses, each RF thermal fuse comprising: a body adapted to be positioned on a transmission line between an RF signal source and an RF device; a conductive bolt positioned in the body, the conductive bolt having a length sufficient to provide an impedance at a point of protection on the transmission line in response to the conductive bolt contacting a live conductor of the transmission line; and a driving mechanism configured to cause the conductive bolt to contact the live conductor in response to a temperature at or near the point of protection exceeding a threshold temperature; wherein the plurality of RF thermal fuses are positioned on the transmission line at intervals such that the plurality of RF thermal fuses provide a combined impedance that is adapted to reflect a portion of the incident power of an RF signal in a predetermined frequency band from the RF signal source. ### Claim 11 (depends on 10) The thermal protection system of claim 10, wherein, for at least one of the plurality of RF thermal fuses, the driving mechanism is irreversible. ### Claim 12 (depends on 11) The thermal protection system of claim 11, wherein the driving mechanism comprises: a spring adapted to apply a force to the conductive bolt in a direction toward the live conductor; and a solder adapted to resist the force applied to the conductive bolt, wherein the solder comprises a soldering material having a melting temperature equal to the threshold temperature. ### Claim 13 (depends on 10) The thermal protection system of claim 10, wherein, for at least one of the plurality of RF thermal fuses, the driving mechanism is reversible. ### Claim 14 (depends on 13) The thermal protection system of claim 13, wherein the driving mechanism comprises a bimetal driving mechanism. ### Claim 15 (depends on 13) The thermal protection system of claim 13, wherein the driving mechanism comprises a chamber enclosing a gas or liquid, wherein the gas or the liquid is expandable such that the gas or the liquid applies pressure to the conductive bolt in response to the threshold temperature. ### Claim 16 (depends on 13) The thermal protection system of claim 13, wherein the driving mechanism comprises an electromagnet configured to oppose a force applied by a spring to the conductive bolt in a direction toward the live conductor, the electromagnet configured to oppose the force in response to the electromagnet receiving a current from the RF device. ### Claim 17 (depends on 13) The thermal protection system of claim 13, wherein the driving mechanism comprises a shape memory alloy spring mechanism. ### Claim 18 (depends on 10) The thermal protection system of claim 10, wherein each of the plurality of RF thermal fuses further comprises a dielectric material positioned at a first end of the conductive bolt opposite a second end of the conductive bolt adapted to contact the live conductor. ### Claim 19 A system comprising: an RF device in communication with an RF signal source via a transmission line; an RF thermal fuse positioned on the transmission line, the RF thermal fuse comprising: a body adapted to be positioned on the transmission line between the RF signal source and the RF device; a conductive bolt positioned in the body, the conductive bolt having a length sufficient to provide an impedance at a point of protection on the transmission line in response to the conductive bolt contacting a live conductor of the transmission line, wherein the impedance is configured to reflect a portion of the incident power of an RF signal from the RF signal source; and a driving mechanism configured to cause the conductive bolt to contact the live conductor in response to a temperature at or near the point of protection exceeding a threshold temperature. ### Claim 20 (depends on 19) The system of claim 19, wherein the RF device comprises a thermal over-temperature protection fuse coupled to at least one component of the RF device, wherein a signal path is provided from the transmission line to the thermal over-temperature protection fuse via the at least one component, wherein the thermal over-temperature protection fuse is configured to open the signal path in response to a temperature of the at least one component exceeding the threshold temperature. ### Claim 21 (depends on 20) The system of claim 20, wherein the thermal over-temperature protection fuse comprises a soldering material adapted to electrically connect the thermal over-temperature protection fuse to the at least one component, wherein the soldering material has a melting temperature less than or equal to the threshold temperature.