Circuit breaker with improved contact structure

Claim 2

A circuit breaker comprising contact means, said contact means comprising a stationary contact structure and a movable contact structure, said movable contact structure comprising a movable support, a main contact arm supported on said movable support, main contact means on said main contact arm, an arcing contact arm supported on said movable support and comprising a portion positioned along side at least a part of said main contact arm, arcing contact means on said arcing contact arm, in the closed position of said contact means the current through said contact means comprising a first current path through said main contact arm and a second current path through said arcing contact arm which first and second current paths are parallel and in the same direction through said portion of said arcing contact arm and said part of said main contact arm whereby electromagnetic forces generated by current through said movable contact structure provides a side thrust between said main contact arm and said arcing contact arm, during opening operations of said contact means said arcing contact arm moving relative to said main contact arm, a separating member of magnetic material supported on said movable support and preventing an application of the force of said side thrust against said arcing contact arm from said main contact arm, current responsive magnetic means operating on said arcing contact arm under high current conditions to bias said arcing contact means against said stationary contact structure, said current responsive magnetic means comprising said separating member of magnetic material.

Claim 3

A circuit breaker according to claim 1, said arcing contact arm being supported for limited pivotal movement on said movable support, and during said opening operations said arcing contact arm pivoting on said movable support to disengage said arcing contact means from said stationary contact means after said main contact means has disengaged from said stationary contact means.

Claim 4

A circuit breaker according to claim 1, a pair of said main contact arms supported on said movable support on opposite sides of said arcing contact arm with said arcing contact arm comprising a portion positioned alongside at least a part of each of said main contact arms, and said member of magnetic material being a rigid generally U-shaped member fixedly supported on said movable support with the opposite legs thereof positioned on opposite sides of said arcing contact arm and with each of said opposite legs being positioned between said arcing contact arm and one of said main contact arms.

Claim 5

A circuit breaker according to claim 3, said arcing contact arm being supported for limited pivotal movement on said support, and during said opening operations said arcing contact arm pivoting a limited movement on said support relative to said main contact arms which limited pivoting movement provides that said arcing contact means will disengage from said stationary contact means after said movable contact means has disengaged from said stationary contact means.

Claim 6

A circuit breaker according to claim 1, said member of magnetic material being a first member of magnetic material fixedly supported on said movable support, a second member of magnetic material fixedly supported on said arcing contact arm cooperating with said first member of magnetic material to provide a magnetic circuit around said arcing contact arm separate from said main contact arm, and said magnetic circuit operating to draw said arcing contact arm toward said stationary contact means under high-current conditions.

Claim 7

A circuit breaker comprising contact means, said contact means comprising a stationary contact structure and a movable contact stRucture, said movable contact structure comprising a movable support, a main contact arm supported on said movable, support for limited movement relative to said movable support and relative to said main contact arm, a first magnetic member supported on said movable support, a second magnetic member supported on said arcing contact arm to provide a magnetic circuit through said first and second magnetic members around said arcing contact arm separate from said main contact arm, in the closed position of said contacts the current through said arcing contact arm generating magnetic flux in said magnetic circuit to draw said first and second magnetic members toward each other to force said arcing contact arm against said stationary contact structure.

Claim 8

A circuit breaker comprising contact means, said contact means comprising a stationary contact structure and a movable contact stRucture, said movable contact structure comprising a movable support, a main contact arm supported on said movable, support for limited movement relative to said movable support and relative to said main contact arm, a first magnetic member supported on said movable support, a second magnetic member supported on said arcing contact arm to provide a magnetic circuit through said first and second magnetic members around said arcing contact arm separate from said main contact arm, in the closed position of said contacts the current through said arcing contact arm generating magnetic flux in said magnetic circuit to draw said first and second magnetic members toward each other to force said arcing contact arm against said stationary contact structure.

Claim 9

A circuit breaker according to claim 6, a pair of said main contact arms supported on said movable support with each of said main contact arms being supported on a different side of said arcing contact arm, said first and second magnetic members forming a magnetic circuit around said arcing contact arm separate from both of said main contact arms.

Claim 10

A circuit breaker according to claim 7, said arcing contact arm being supported for limited pivotal movement on said movable support, an arcing contact on said arcing contact arm on a first side of the pivot of said arcing contact arm, and said second magnetic member being positioned on said arcing contact arm on the side of said pivot opposite said first side.

Claim 11

A circuit breaker according to claim 8, said first magnetic member comprising a U-shaped magnetic member supported on said movable support with the opposite legs thereof positioned on opposite sides of said arcing contact arm and with each of the said opposite legs being positioned between said arcing contact arm and the adjacent main contact arm.

Claim 12

A circuit breaker comprising a pair of spaced stationary conductors, a stationary contact on a first of said stationary conductors, a movable contact structure comprising a movable contact arm and a movable contact on said movable contact arm, a flexible conductor electrically connecting said movable contact arm with the second of said stationary conductors, a movable contact support, pivot support means supporting said movable contact arm for a limited generally pivotal movement on said movable contact support, spring means biasing said movable contact arm about said pivot support means toward said stationary contact, stop means limiting movement of said movable contact arm on said movable contact support about said pivot support means toward said stationary contact, means supporting said movable contact support for movement between open and closed positions, in the open position of said contacts said spring means biasing said movable contact arm on said movable contact support about said pivot support means which movement is limited by said stop means: during closing operations of said circuit breaker said movable contact arm moving unitarily with said movable contact support until said movable contact engages such stationary contact and thereafter said movable contact support moving to the fully closed position charging said spring means as said movable contact arm moves relative to said movable contact support on said pivot support means; during opening operations of said circuit breaker said movable contact support member moving toward the open position an initial movement as said charged spring means discharges with said movable contact in engagement with said stationary contact and with said movable contact arm moving relative to said movable contact support on said pivot support means until said relative movement of said movable contact arm is limited by said stop means and thereafter said movable contact support carrying said movable contact arm therewith as a unit to the fully open position; said circuit breaker comprising means operating upon the occurrence of overload current conditions above a predetermined value to effect automatic oPening of said contacts; and magnetic means other than said flexible conductor on said movable contact structure responsive to current flow in said movable contact arm, said movable contact being on said movable contact arm on a first side of said pivot support means, said magnetic means operating on said movable contact arm on the second side of said pivot support means opposite said first side, and upon the occurrence of overload current conditions when said contacts are automatically opened said magnetic means operating to bias said movable contact arm to provide contact pressure between said movable contact and said stationary contact as said movable contact support moves said initial movement toward the open position while said charged spring means discharges with said movable contact in engagement with said stationary contact and with said movable contact arm moving relative to said movable contact support on said pivot support means until said relative movement of said movable contact arm is limited by said stop means and thereafter said movable contact support carrying said movable contact arm therewith as a unit to the fully opened position.

Claim 13

A circuit breaker comprising a pair of spaced stationary conductors, a stationary contact on a first of said stationary conductors, a movable contact structure comprising a movable contact arm and a movable contact on said movable contact arm, a flexible conductor electrically connecting said movable contact arm with the second of said stationary conductors, a movable contact support, pivot support means supporting said movable contact arm for a limited generally pivotal movement on said movable contact support, spring means biasing said movable contact arm about said pivot support means toward said stationary contact, stop means limiting movement of said movable contact arm on said movable contact support about said pivot support means toward said stationary contact, means supporting said movable contact support for movement between open and closed positions, in the open position of said contacts said spring means biasing said movable contact arm on said movable contact support about said pivot support means which movement is limited by said stop means: during closing operations of said circuit breaker said movable contact arm moving unitarily with said movable contact support until said movable contact engages such stationary contact and thereafter said movable contact support moving to the fully closed position charging said spring means as said movable contact arm moves relative to said movable contact support on said pivot support means; during opening operations of said circuit breaker said movable contact support member moving toward the open position an initial movement as said charged spring means discharges with said movable contact in engagement with said stationary contact and with said movable contact arm moving relative to said movable contact support on said pivot support means until said relative movement of said movable contact arm is limited by said stop means and thereafter said movable contact support carrying said movable contact arm therewith as a unit to the fully open position; said circuit breaker comprising means operating upon the occurrence of overload current conditions above a predetermined value to effect automatic oPening of said contacts; and magnetic means other than said flexible conductor on said movable contact structure responsive to current flow in said movable contact arm, said movable contact being on said movable contact arm on a first side of said pivot support means, said magnetic means operating on said movable contact arm on the second side of said pivot support means opposite said first side, and upon the occurrence of overload current conditions when said contacts are automatically opened said magnetic means operating to bias said movable contact arm to provide contact pressure between said movable contact and said stationary contact as said movable contact support moves said initial movement toward the open position while said charged spring means discharges with said movable contact in engagement with said stationary contact and with said movable contact arm moving relative to said movable contact support on said pivot support means until said relative movement of said movable contact arm is limited by said stop means and thereafter said movable contact support carrying said movable contact arm therewith as a unit to the fully opened position.

Claim 14

A circuit breaker according to claim 10, said magnetic means comprising a first member of magnetic material on said contact support member and a second member of magnetic material on said movable contact arm which first and second members of magnetic material provide a magnetic circuit around said movable contact arm responsive to the current flow in said movable contact arm.

Claim 15

A circuit breaker according to claim 10, said movable contact structure comprising main movable contact means supported on said movable contact support, in the closed position of said movable contact structure said main movable contact means on said movable contact support being in a closed position to carry current between said spaced stationary conductors, and during opening operations of said circuit breaker said main movable contact means moving to an open position to transfer current to said movable contact arm as said movable contact arm pivots on said pivot support means said limited movement of said movable contact arm relative to said movable contact support.

Claim 16

A circuit breaker according to claim 12, said magnetic means on said movable contact structure comprising a first member of magnetic material on said movable contact support and a second member of magnetic material on said movable contact arm which first and second members of magnetic material provide a magnetic circuit around said movable contact arm responsive to current flow in said movable contact arm.

Claim 17

A circuit breaker according to claim 10, said magnetic means comprising an inverted generally U-shaped first member of magnetic material supported at the bight portion thereof on said movable contact support with the opposite legs thereof extending downwardly on opposite sides of said movable contact arm on said second side of said pivot support means, said magnetic means comprising a second member of magnetic material supported on said movable contact arm on said second side of said pivot support means cooperating with said first member of magnetic material to provide a magnetic circuit around said movable contact arm on said second side of said pivot support means which magnetic circuit is responsive to the current flow in said movable contact arm to bias said movable contact arm about said pivot support means to provide contact pressure between said movable contact and said stationary contact.

Claim 18

A circuit breaker according to claim 14, said spaced stationary conductors comprising main stationary contact means, said movable contact structure comprising main movable contact means supported on said movable contact support, in the closed position of said movable contact structure said main movable contact means being in a closed position carrying current between said stationary conductors, during opening operations of said movable contact structure said main movable contact means moving to an open position to transfer current to said movable contact arm while said movable contact arm pivots on said pivot support means said limited pivotal movement during which limited pivotal movement said magnetic means responsive to the current flow in said movable contact arm biases said movable contact into engagement with said stationary contact, and during closing operations of said circuit breaker said movable contact engaging said stationary contact before said main contact means reachs its closed current carrying position and thereafter said movable contact structure moving to the fully closed position as said movable contact arm pivots said limited pivotal movement on said movable contact support during which limited pivotal movement said magnetic means operates on said movable contact arm in response to the current flow in said movable contact arm to bias said movable contact into engagement with said stationary contact.

Claim 19

A circuit breaker comprising a pair of spaced stationary conductors, a stationary contact on a first of said stationary conductors, a movable contact structure comprising a movable contact arm and a movable contact on said movable contact arm, a movable contact support, a flexible conductor electrically connecting said movable contact arm with the second of said stationary conductors, pivot support means supporting said movable contact arm for limited pivotal movement on said movable contact support, spring means on said movable contact structure biasing said movable contact arm about said pivot support means toward said stationary contact, stop means limiting pivotal movement of said movable contact arm on said movable contact support about said pivot support means toward said stationary contact, means supporting said movable contact support for movement between open and closed positions, in the open position said spring means biasing said movable contact arm about said pivot support means toward said stationary contact which movement is limited by said stop means: during closing operations of said circuit breaker said movable contact arm moving unitarily with said contact support member until said movable contact engages said stationary contact and thereafter said movable contact support moving to the fully closed position charging said spring means as said movable contact arm moves relative to said movable contact support on said pivot support means; during opening operations of said circuit breaker said movable contact support moving toward the open position an initial movement as said charged spring means discharges with said movable contact in engagement with said stationary contact and with said movable contact arm moving relative to said movable contact support on said pivot support means until said relative movement is limited by said stop means and thereafter said movable contact support carrying said movable contact therewith as a unit to the fully open position; and said circuit breaker comprising means operating upon the occurrence of overload current conditions above a predetermined value to effect automatic opening of said contacts; magnetic means on said movable contact structure, said magnetic means comprising a first magnetic member on said movable contact support and a second magnetic member on said movable contact arm, said movable contact being on said movable contact arm on a first side of said pivot support means, said first and second magnetic members providing a magnetic circuit around said movable contact arm on the second side of said pivot support means opposite said first side which magnetic circuit is responsive to current flow in said movable contact arm to bias said movable contact arm about said pivot support means to provide contact pressure between said movable and stationary contacts.

Claim 20

A circuit breaker comprising a pair of spaced stationary conductors, a stationary contact on a first of said stationary conductors, a movable contact structure comprising a movable contact arm and a movable contact on said movable contact arm, a movable contact support, a flexible conductor electrically connecting said movable contact arm with the second of said stationary conductors, pivot support means supporting said movable contact arm for limited pivotal movement on said movable contact support, spring means on said movable contact structure biasing said movable contact arm about said pivot support means toward said stationary contact, stop means limiting pivotal movement of said movable contact arm on said movable contact support about said pivot support means toward said stationary contact, means supporting said movable contact support for movement between open and closed positions, in the open position said spring means biasing said movable contact arm about said pivot support means toward said stationary contact which movement is limited by said stop means: during closing operations of said circuit breaker said movable contact arm moving unitarily with said contact support member until said movable contact engages said stationary contact and thereafter said movable contact support moving to the fully closed position charging said spring means as said movable contact arm moves relative to said movable contact support on said pivot support means; during opening operations of said circuit breaker said movable contact support moving toward the open position an initial movement as said charged spring means discharges with said movable contact in engagement with said stationary contact and with said movable contact arm moving relative to said movable contact support on said pivot support means until said relative movement is limited by said stop means and thereafter said movable contact support carrying said movable contact therewith as a unit to the fully open position; and said circuit breaker comprising means operating upon the occurrence of overload current conditions above a predetermined value to effect automatic opening of said contacts; magnetic means on said movable contact structure, said magnetic means comprising a first magnetic member on said movable contact support and a second magnetic member on said movable contact arm, said movable contact being on said movable contact arm on a first side of said pivot support means, said first and second magnetic members providing a magnetic circuit around said movable contact arm on the second side of said pivot support means opposite said first side which magnetic circuit is responsive to current flow in said movable contact arm to bias said movable contact arm about said pivot support means to provide contact pressure between said movable and stationary contacts.

Claim 21

A circuit breaker according to claim 16, said spaced stationary conductors comprising main stationary contact means, main movable contact means supported on said movablE contact support to cooperate with said main stationary contact means, during opening operations of said movable contact structure said main movable contact means disengaging from said main stationary contact means to transfer current to said movable contact arm as said movable contact arm moves said limited pivotal movement on said movable contact support, during closing operations of said movable contact structure said movable contact engaging said stationary contact before said main movable contact means fully engages said main stationary contact means and thereafter said movable contact arm moving said limited pivotal movement on said movable contact support as said main movable contact means moves into full engagement with said main stationary contact means.

Claim 22

A circuit breaker according to claim 17, said magnetic circuit around said movable contact arm operating on said movable contact arm separate from said main movable contact means, and said movable contact structure being supported for pivotal movement between open and closed positions.

Claim 23

A circuit breaker according to claim 17, said first magnetic member being a generally U-shaped magnetic member supported at the bight portion thereof on said movable contact support with the opposite legs thereof extending downwardly on opposite sides of said movable contact arm, said second magnetic member being supported on said movable contact arm to cooperate with said generally U-shaped first magnetic member to provide said magnetic circuit around said movable contact arm.

Claim 24

A circuit breaker according to claim 18, and said main contact means comprising a pair of bridging main contact members supported on opposite sides of said movable contact arm to engage said stationary main contact means and bridge said pair of spaced stationary conductors in the closed position of said movable contact structure.

Claim 25

A circuit breaker comprising a circuit-breaker structure, said circuit-breaker structure comprising a first stationary conductor, a second stationary conductor spaced from said first stationary conductor, an arc extinguishing structure, a first and arcing stationary contact means on said first stationary conductor in proximity to said arc-extinguishing structure, a second stationary contact means on said first stationary conductor, a third stationary contact means on said second stationary conductor: a movable contact device, said movable contact device comprising a movable contact support, an arcing-contact support arm connected to said movable contact support for movement with said movable contact support between open and closed positions and for limited movement relative to said movable contact structure, a first and arcing movable contact on said arcing-contact support arm, contact-pressure spring means biasing said arcing-contact support arm relative to said movable contact support toward said first and arcing stationary contact means, a pair of bridging contact support arms supported on said movable contact support on opposite sides of said arcing-contact support arm for movement with said movable contact support between open and closed positions and for limited movement relative to said movable contact support, a separate second movable contact and a separate third movable contact on each of said bridging contact support arms, said contact-pressure spring means biasing said bridging contact support arms relative to said movable contact support toward said second and third stationary contact means; said movable contact device being movable between closed and opened positions to close and open and electric circuit, in the closed position of said contacts said first and arcing movable contact engaging said first and arcing stationary contact means, said second movable contact engaging said second stationary contact means and said third movable contacts engaging said third stationary contact means; said movable contact structure comprising current-responsive magnetic means responsive to curreNt flow in said arcing-contact support arm to bias said arcing-contact support arm to provide contact pressure between said first and arcing movable contact and said first and arcing stationary contact means; said circuit breaker comprising trip means operating automatically upon the occurrence of overload current conditions above a predetermined value to effect automatic opening of said movable contact device; and during said automatic opening of said movable contact device upon the occurrence of said overload current conditions said second movable contacts disengaging from said second stationary contact means as said arcing-contact support arm moves said limited movement relative to said movable contact support to transfer current to said arcing-contact support arm and after said limited movement of said arcing-contact support arm relative to said movable contact support is taken up said arcing-contact support arm moving as a unit with said movable contact support to the open position.

Claim 26

A circuit breaker comprising a circuit-breaker structure, said circuit-breaker structure comprising a first stationary conductor, a second stationary conductor spaced from said first stationary conductor, an arc extinguishing structure, a first and arcing stationary contact means on said first stationary conductor in proximity to said arc-extinguishing structure, a second stationary contact means on said first stationary conductor, a third stationary contact means on said second stationary conductor: a movable contact device, said movable contact device comprising a movable contact support, an arcing-contact support arm connected to said movable contact support for movement with said movable contact support between open and closed positions and for limited movement relative to said movable contact structure, a first and arcing movable contact on said arcing-contact support arm, contact-pressure spring means biasing said arcing-contact support arm relative to said movable contact support toward said first and arcing stationary contact means, a pair of bridging contact support arms supported on said movable contact support on opposite sides of said arcing-contact support arm for movement with said movable contact support between open and closed positions and for limited movement relative to said movable contact support, a separate second movable contact and a separate third movable contact on each of said bridging contact support arms, said contact-pressure spring means biasing said bridging contact support arms relative to said movable contact support toward said second and third stationary contact means; said movable contact device being movable between closed and opened positions to close and open and electric circuit, in the closed position of said contacts said first and arcing movable contact engaging said first and arcing stationary contact means, said second movable contact engaging said second stationary contact means and said third movable contacts engaging said third stationary contact means; said movable contact structure comprising current-responsive magnetic means responsive to curreNt flow in said arcing-contact support arm to bias said arcing-contact support arm to provide contact pressure between said first and arcing movable contact and said first and arcing stationary contact means; said circuit breaker comprising trip means operating automatically upon the occurrence of overload current conditions above a predetermined value to effect automatic opening of said movable contact device; and during said automatic opening of said movable contact device upon the occurrence of said overload current conditions said second movable contacts disengaging from said second stationary contact means as said arcing-contact support arm moves said limited movement relative to said movable contact support to transfer current to said arcing-contact support arm and after said limited movement of said arcing-contact support arm relative to said movable contact support is taken up said arcing-contact support arm moving as a unit with said movable contact support to the open position.

Claim 27

A circuit breaker according to claim 21, said magnetic means comprising a first member of magnetic material supported on said movable contact support and a second member of magnetic material supported on said arcing-contact support arm providing a magnetic circuit responsive to current flow in said arcing-contact support arm to bias said arcing-contact support arm to provide contact pressure between said first and arcing movable contact and said first and arcing stationary contact means.

Claim 28

A circuit breaker according to clam 22, pivot support means supporting said arcing-contact support arm on said movable contact support for limited pivotal movement on said movable contact support relative to said movable contact support, said first and arcing movable contact being on said arcing-contact support arm on a first side of said pivot support means, said first and second magnetic members operating on said arcing-contact support arm on the second side of said pivot support means opposite the said first side, said first and second magnetic members operating in response to current flow in said arcing-contact support arm to bias said arcing-contact support arm about said pivot support means to provide said contact pressure between said first and arcing movable contact and said first and arcing stationary contact means.

Claim 29

A circuit breaker according to clam 22, pivot support means supporting said arcing-contact support arm on said movable contact support for limited pivotal movement on said movable contact support relative to said movable contact support, said first and arcing movable contact being on said arcing-contact support arm on a first side of said pivot support means, said first and second magnetic members operating on said arcing-contact support arm on the second side of said pivot support means opposite the said first side, said first and second magnetic members operating in response to current flow in said arcing-contact support arm to bias said arcing-contact support arm about said pivot support means to provide said contact pressure between said first and arcing movable contact and said first and arcing stationary contact means.

Claim 30

A circuit breaker according to claim 23, said magnetic means comprising a first generally U-shaped magnetic member supported at the bight portion thereof on said support member with the opposite legs thereof extending on opposite sides of said arcing-contact support arm on said second side of said pivot support means, said magnetic means comprising said second member of magnetic material supported on said arcing-contact support arm on the said second side of said pivot support means to cooperate with said generally U-shaped member of magnetic material to provide a magnetic circuit around said arcing-contact support arm separate from said bridging contact support arms which magnetic circuit is responsive to current flow in said arcing-contact support arm.

Claim 31

A circuit breaker according to claim 24, and a flexible conductor connected at one end thereof to said arcing-contact support arm and at the other end thereof to said second stationary conductor to electrically connect said arcing-contact support arm to said second stationary conductor.