Circuit protector

Claim 2

A circuit protector comprising a casing of an insulating material having a top plate and a separable bottom plate, first and second spaced terminal members fixedly mounted on said bottom plate and extending internally and externally of said casing, a permanent magnet secured at a fixed position substantially centrally within the casing intermediate said first and second terminal members, a body of magnetic and electrically conductive material normally held attracted by both N- and S- poles of the permanent magnet, said body comprising a material having a magnetic permeability which is subject to a large variation with temperature changes resulting from excessive current flow therethrough, the body having its opposite ends electrically connected to the first and second terminal members respectively, whereby excessive current flowing between said first and second terminals via said body is operative to vary the magnetic attraction between said magnet and body, means for holding one end of the body for pivotable movement with respect to the permanent magnet, the inner end of said first terminal member extending past the side of the permanent magnet facing the top plate of the casing to a position closely adjacent the free end of the body, a pair of opening and closing contacts placed between the free end of the body and the first terminal member in series therewith, and means for biasing the body in a direction away from the permanent magnet.

Claim 3

A circuit protector according to claim 1, further including a third terminal member fixedly mounted on the casing and extending internally and externally thereof, and second opening and closing contacts placed between the third and second terminal members respectively and adapted to be controlled by pivotal motion of the body.

Claim 4

A circuit protector according to claim 1, further including a hollow protrusion extending outwardly from the casing, a reset button extending through the side walls of the protrusion for bidirectional movement in the direction of motion of the free end of said pivotally mounted body, and means within the casing for engaging the reset button with the free end of the body.

Claim 5

A circuit protector according to claim 1, further including a conductive leaf spring mounted on the first terminal member at a position adjacent the free end of the body, said pair of contacts being mounted respectively on the leaf spring and body, said leaf spring urging said contacts into engagement with each other.

Claim 6

A circuit protector according to claim 1, in which the biasing means comprises a U-shaped leaf spring having its one limb secured to one end of the body and its other limb secured to the second terminal member, said biasing means supporting the body for pivotal motion.

Claim 7

A circuit protector according to claim 2, in which the third terminal member is mounted in the bottom plate on the opposite side of the second termInal member from the permanent magnet.

Claim 8

A circuit protector comprising a casing of insulating material, first and second laterally spaced terminal members fixedly mounted in the bottom plate of the casing and extending internally and externally thereof, a permanent magnet secured substantially centrally within the casing intermediate the first and second terminal members, a plate-shaped body of magnetic and electrically conductive material, the body being normally held attracted to both the N- and S-pole of the permanent magnet and having a magnetic permeability which is subject to a large variation with temperature change, a U-shaped conductive leaf spring having its limbs secured to the second terminal member and to one end of said body respectively, said leaf spring being operative to bias the body in a direction away from the permanent magnet, a second conductive leaf spring secured to the first terminal member adjacent the other end of the body, a first pair of opening and closing contacts interposed between the second leaf spring and the body, the second leaf spring being effective to urge the contacts into abutment and to bias the body in a direction away from the permanent magnet, a hollow protrusion formed in the top plate of the casing and extending externally thereof, a rod-shaped reset button slidably extending through lateral sidewalls of the hollow protrusion, and means for holding a portion of the body in engagement with the reset button, the sum of the biasing force of the U-shaped and second leaf springs being greater than the force of attraction acting between the body and the magnet when a current in excess of a given value flows across the first and second terminal members, whereby the body moves away from the magnet to open the circuit between the first pair of contacts upon occurrence of said excess current flow.

Claim 9

A circuit protector comprising a casing of insulating material, first and second laterally spaced terminal members fixedly mounted in the bottom plate of the casing and extending internally and externally thereof, a permanent magnet secured substantially centrally within the casing intermediate the first and second terminal members, a plate-shaped body of magnetic and electrically conductive material, the body being normally held attracted to both the N- and S-pole of the permanent magnet and having a magnetic permeability which is subject to a large variation with temperature change, a U-shaped conductive leaf spring having its limbs secured to the second terminal member and to one end of said body respectively, said leaf spring being operative to bias the body in a direction away from the permanent magnet, a second conductive leaf spring secured to the first terminal member adjacent the other end of the body, a first pair of opening and closing contacts interposed between the second leaf spring and the body, the second leaf spring being effective to urge the contacts into abutment and to bias the body in a direction away from the permanent magnet, a hollow protrusion formed in the top plate of the casing and extending externally thereof, a rod-shaped reset button slidably extending through lateral sidewalls of the hollow protrusion, and means for holding a portion of the body in engagement with the reset button, the sum of the biasing force of the U-shaped and second leaf springs being greater than the force of attraction acting between the body and the magnet when a current in excess of a given value flows across the first and second terminal members, whereby the body moves away from the magnet to open the circuit between the first pair of contacts upon occurrence of said excess current flow.

Claim 10

A circuit protector according to claim 7, further including a third terminal member secured to the bottom plate of the casing on the opposite side from the first terminal member with respect to the second terminal member, and a second pair of opening and closing contacts interposed between the third terminal member and the body and adapted to close when the body moves away from the magnet.

Claim 11

A circuit protector according to claim 7, further including a holder formed integrally with the casing and extending inwardly therefrom, said holder including a recess formed therein for reception of the permanent magnet.