Circuit breaker

Claim 2

A circuit breaker comprising: terminal means for receiving a power source; stationary contact means connected to said power source terminal means; load terminal means; a movable lever swingably supported at a portion thereof to move between a first and a second position and having movable contact means disposed on one free end of the movable lever, said movable contact means being movable between said first position at which said movable contact means is brought into contact with said stationary contact means and said second position at which said movable contact means separates from said stationary contact means; bias means for biasing said movable lever at said second position; means for normally urging said movable lever toward said first position against said bias means; current sensing means for producing a first signal by detecting an overload current and a second signal by detecting a short-circuit current; overload current responsive means actuated in response to said first signal to render inoperable said urging means to thereby displace said movable lever to said second position and automatically deactuated in response to the disappearance of said first signal; short-circuit current responsive means for actuating said overload current responsive means in response to said second signal, said short circuit current responsive means being deactuated automatically in response to the disappearance of said second signal; short-circuit indicating means for effecting a short-circuit indication automatically in response to the actuation of said short-circuit current responsive means, said short-circuit indicating means being resettable manually thereby removing said short-circuit indication; and holding means for holding the actuation of said short-circuit current responsive means in response to the actuation of said short-circuit current responsive means, said holding means releasing the holding of said actuation of said short-circuit current responsive means in response to the resetting of said short-circuit indicating means.

Claim 3

The circuit breaker according to claim 1, wherein said current sensing means includes a magnetic pole piece and a coil wound around the magnetic pole piece and having connections to said movable contact means and said load terminal means, thereby said current sensing means producing a first magnetic flux in response to an overload current flowing through the coil and a second magnetic flux in response to a short-circuit current flowing through the coil.

Claim 4

The circuit breaker according to claim 2, wherein said overload current responsive means includes a first movable iron plate, said first movable iron plate being actuated in response to said first magnetic flux to render invalid said urging means thereby to displace said movable lever at said second position and automatically deactuated in response to disappearance of said first magnetic flux, and said short-circuit current responsive means includes a second movable iron plate, said second movable iron plate actuating said first movable iron plate in response to said second magnetic flux.

Claim 5

The circuit breaker according to claim 3, wherein said holding means holds said second movable iron plate once actuated in its actuated position.

Claim 6

The circuit breaker according to claim 4, wherein said short-circuit indicating means includes a short-circuit indicating member and a spring member for normally biasing the short-circuit indicating member to a position at which a short-circuit indication is not effected, said short-circuit indicating member moved in response to the actuation of said second movable iron plate against the biasing force of said spring member to effect a short-circuit indication.

Claim 7

The circuit breaker according to claim 5, wherein said first movable iron plate is rotatably mounted at a longitudinal intermediate portion thereof and having one end which is opposed to said magnetic pole piece and which is biased by a first spring to normally separate from said magnetic pole piece with the other end engaged with said urging means, said first movable iron plate being turned in response to said first magnetic flux against said first spring with the one end attracted and adhering to said magnetic pole piece and with the other end moved to render invalid said urging means, and said second movable iron plate is rotatably mounted at a longitudinal intermediate portion thereof and having one end which is opposed to said magnetic pole piece in part, which is provided with a tab member opposed to the one end of said first movable iron plate and which is biased by a second spring to normally separate from said magnetic pole piece, said second movable iron plate being turned in response to said second magnetic flux with the tab member attracted and seized by said magnetic pole piece while pressing down the one end of said first movable iron plate.

Claim 8

The circuit breaker according to claim 6, wherein said short-circuit indicating member is engaged with the other end of said second movable iron plate and moved in response to the turning of said second movable iron plate against said spring member thereby to effect a short-circuit indication.

Claim 9

The circuit breaker according to claim 7, wherein said holding means comprises a leaf spring including a bent portion for effecting positional regulation of said second movable iron plate against said second spring and a swell portion for holding in place the one end of said second movable iron plate when said one end is attracted and adhering to said magnetic pole piece.

Claim 10

The circuit breaker according to claim 1, wherein said power source terminal means includes more than two terminals for receiving a multiple-phase power source, said stationary contact means includes more than two stationary contacts connected correspondingly to said power source terminals, said movable contact means includes more than two movable contacts each brought into contact with the corresponding stationary contact at said first position, said current sensing means includes more than two magnetic pole pieces and more than two coils each wound around the corresponding magnetic pole piece and connected to the corresponding movable contact and load terminal, said coils each producing in response to an overload current flowing therethrough a first magnetic flux and is response to a short-circuit current flowing therethrough a second magnetic flux, said overload current responsive means includes more than two first movable iron plates, each of said first movable iron plates being rotatably mounted at a longitudinal intermediate portion thereof and having one end which is opposed to the corresponding magnetic pole piece and which is biased by a first spring to normally separate from the corresponding magnetic pole piece with the other end engaged with said urging means, said first movable iron plate being turned in response to said first magnetic flux of the corresponding coil against said first spring with the one end attracted and adhering to the corresponding magnetic pole piece and with the other end moved to render invalid said urging means thereby to displace said movable lever to said second position, said first movable iron plate being automatically deactuated in response to disappearance of said first magnetic flux, said short-circuit current responsive means includes more than two second movable iron plates, each of said second movable iron plates being rotatably mounted at a longitudinal intermediate portion thereof and having one end which is opposed to the corresponding magnetic pole piece in part, which is provided with a tab member opposed to the one end of the corresponding first movable iron plate and which is biased by a second spring to normally separate from the corresponding magnetic pole piece, said second movable iron plate being turned in response to said second magnetic flux of the corresponding coil with the tab member attracted and adhered to the corresponding magnetic pole piece while pressing down the one end of the corresponding first movable iron plate, said short-circuit indicating means includes more than two short-circuit indicating members and more than two spring members each normally biasing the corresponding short-circuit indicating member to a position at which a short-circuit indication is not effected, each of said short-circuit indicating members being engaged with the other end of the corresponding second movable iron plate and moved in response to the turning of the corresponding second movable against the corresponding spring member thereby to effect a short-circuit indication, said holding means includes more than two leaf springs corresponding to said second movable iron plates, each of said leaf spring including a bent portion for effecting positional regulation of the corresponding second movable iron plate against the corresponding second spring and a swell portion for holding in place the one end of the corresponding second movable iron plate when said one end is attracted and adhering to the corresponding magnetic pole piece.