# US 4,393,288 A · Circuit breaker > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,393,288 A - Document ID: US4393288A - Status: Granted - Kind: A - Application number: 06/276,574 - Filed: 1981-06-23 - Granted: 1983-07-12 - Earliest claimed: 1981-06-23 - Assignees: GTE Products Corporation - Inventors: Harold E. Belttary - Web page: https://patentgrep.com/patent/US4393288A ## CPC - H01H 73/18: Means for extinguishing or suppressing arc {(magnet coil acting as blow-out device H01H71/38)} - H01H 9/342: {Venting arrangements for arc chutes} - H01H 33/76: wherein arc-extinguishing gas is evolved from stationary parts; Selection of material therefor - 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) ## Abstract An improved circuit breaker utilizing the combination of a pair of composition sheets and a channel. The sheets reside alongside opposing interior surfaces of a molded insulated housing and are held in place within recesses formed therein. The sheets are formed of material comprising a water-insoluble binder and an arc-suppressing substances selected from the class consisting of the oxides and hydrates of aluminum and magnesium, the binder constituting at least ten percent of the composition. The channel comprises an integral, generally U-shaped member forming a base and opposing side walls. One end of the side walls has extending widths to provide enlarged surfaces for engaging the composition sheets. Both ends of the base are formed with a tab for engaging a molded feature within the circuit breaker housing. The tabs and the composition sheets space the channel away from the interior surfaces of the housing, thereby exposing surfaces of the channel not in contact with the sheets. The base has venting holes. The sheets physically contact the extending widths of the channel, but do not physically engage a majority of the length of the channel. The sheets, in addition to having arc suppression characteristics, support the channel away from the molded housing, and thermally insulate the channel from the housing. ## Claims ### Claim 1 In a circuit breaker including two electroconductive elements between which an arc may form, a molded insulated housing having a pair of opposing interior surfaces with each of said surfaces having an opposing formed recess extending along and close to the arc-path between said electroconductive elements, at least one of said electroconductive elements being supported from said molded housing, said molded housing being rigid and possessed of sufficient structural strength to be self-supporting, the improvement comprising the combination of a pair of composition sheets, each said sheet residing alongside a respective said opposing surface and held in place within a respective said formed recess, said composition sheets including material comprising a water-insoluble binder and an arc suppressing substance selected from the class consisting of the oxides and hydrates of aluminum and magnesium, said binder constituting at least ten percent of the composition; and a channel for providing electric arc cooling and quenching within said circuit breaker comprising an integral, generally U-shaped member forming a base and opposing side walls having a length from one end to an opposite end, said one end of said opposing side walls having extending widths thereby providing a pair of enlarged side wall surfaces for engaging with and being held by said composition sheets, each of said one end and said opposite end of said base being formed with an extending tab for engaging a molded feature of an interior surface of said molded housing, whereby said extending tabs and said composition sheets are adapted to space said channel away from said interior surfaces of said molded housing, thereby exposing surfaces of said channel not in contact with said sheets, said base having an arrangement of venting holes therein, and wherein said composition sheets physically contact said extending widths of said channel but physically do not engage a majority of said length of said channel whereby said composition sheets, in addition to having arc suppression characteristics, also support said channel away from said molded housing, thereby helping exhaust gases produced during arcing to vent both through said venting holes and along said exposing surfaces of said channel, said sheets further insulating said channel thermally from said housing. ### Claim 2 (depends on 1) The combination as recited in claim 1 with the addition that said arc-suppressing substance is one of said hydrates and constitutes between five and ninety percent of the composition. ### Claim 3 (depends on 1) The combination as recited in claim 1 with the addition that said binder is inorganic, said arc-suppressing substance being one of said oxides and constituting betfween ten and ninety percent of the composition. ### Claim 4 (depends on 1) The combination as recited in claim 1 with the addition that said composition comprises about seventy percent of said arc-suppressing substance, about fifteen percent of asbestos, and about fifteen percent of a binder. ### Claim 5 (depends on 1) The combination as recited in claim 1 with the addition that said binder is organic, said arc-suppressing substance being an aluminum compound. ### Claim 6 (depends on 1) The combination as recited in claim 1 with the addition that said binder is organic, said arc-suppressing substance being one of said hydrates. ### Claim 7 (depends on 1) The combination as recited in claim 1 with the addition that said binder is organic, said arc-suppressing substance being an aluminum hydrate. ### Claim 8 (depends on 1) The combination as recited in claim 1 wherein said channel is steel. ### Claim 9 (depends on 1) The circuit breaker as recited in claim 1 further including a vent passage within said breaker housing exterior to said channel, said housing having molded projections therein located at said vent passage, and in proximity to said holes to provide cooling surfaces, but spaced away from said holes sufficiently to provide passage of expulsive gases.