Automatic circuit breaker with magnetic latching means

Claim 1

A compact circuit protector comprising a casing, first and second conductive leaf springs spaced apart and secured within the casing at one end thereof, each of said leaf springs extending a length in the same direction from the secured end and then being bent to extend toward each other, first and second terminals secured to the casing in contact with said first and second conductive leaf springs and extending to the exterior of the casinG, said terminals being adapted for connection with a circuit to be protected, a conductive, magnetic plate extending between the other ends of the first and second conductive leaf springs and mounted on the other end of the second conductive leaf spring, first and second contacts attached to the other end of the first conductive leaf spring and to the free end of the conductive, magnetic plate, respectively, at positions opposite each other, a permanent magnet disposed adjacent and opposite the conductive, magnetic plate for attracting and holding the magnetic plate magnetically so as to keep the second contact in electrical contact with first contact, a third spring secured to the casing for holding the permanent magnet in place, and an operating member mounted to the casing and operable to cause the permanent magnet to be displaced manually, said permanent magnet and said second conductive leaf spring being constructed and arranged such that in the event of an overcurrent above a given level flowing across the first and second terminals and through the conductive, magnetic plate, the magnetic attraction between the permanent magnet and the conductive, magnetic diminishes to cause the latter to move away from the permanent magnet by resilience of the second conductive leaf spring to thereby move the first and second contacts apart from each other, said operating member being thereafter operable to move the permanent magnet against the resilience of the third spring until it captures the conductive, magnetic plate again, whereupon the resilience of the third spring is effective to bring the conductive, magnetic plate back to its original position in which the second contact engages the first contact.