US3246097A

US3246097A - Circuit breaker

Info

Publication number: US3246097A
Application number: US312127A
Authority: US
Inventors: Jr William J Pendy; Yorgin Nick
Original assignee: Westinghouse Electric Corp
Current assignee: Westinghouse Electric Corp
Priority date: 1963-09-27
Filing date: 1963-09-27
Publication date: 1966-04-12
Anticipated expiration: 1983-04-12
Also published as: JPS4014649B1

Description

April 12, 1966 w. J. PENDY, JR., ETAL 3,246,097

C IRCUI T BREAKER Filed Sept. 27, 1963 2 Sheets-Sheet l und Nick Yorgin BY (I WM w. awa

ATTORNEY April 12, 1966 w. J. PENDY, JR., ETAL 3,246,097

CIRCUIT BREAKER Filed Sept. 27: 1,965

2 Sheets-Sheet 2 United States Patent O 3,246,097 CIRCUIT BREAKER William J. Pendy, Jr., Chippewa Township, and Nick Yorgin, Economy, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Sept. 27, 1963, Ser. No. 312,127 7 Claims. (Cl. 20G-88) This invention relates generally to circuit breakers and more particularly to circuit breakers for controlling lighting and moderate power circuits.

Some types of circuit breakers are constructed with a rigid and stationary stop that is engaged by the movable contact structure to limit opening movement of the movable contact structure. During normal manual on and oil operations, this means for stopping the movable contact structure is generally satisfactory. During automatic circuit interruption, however, the opening movement of the movable contact structure is highly accelerated by magnetic forces generated by the overload current that is being interrupted. When the highly accelerated movable contact structure hits a solid stop, it rebounds, in some instances as much as 6/7 of the original opening distance, toward the closed position to sometimes cause a restriking of the arc thereby delaying interruption of the damaging overload.

An object of this invention is to provide a circuit breaker with improved means for arresting rebound of the movable contact structure during automatic opening operations.

Another object of this invention is to provide an improved standard type of circuit breaker with improved relatively simple and inexpensive means for arresting rebound of the movable contact structure during automatic opening operations.

A further object of this invention is to provide a circuit breaker with improved means for arresting rebound of the movable contact structure and for nally stopping the parts with the handle positioned to provide a Visual indication that the breaker has tripped.

The invention, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description when read in conjunction with the accompanying drawings:

FIGURE 1 is a vertical sectional view of the center pole of a three-pole circuit breaker embodying the principals of this invention;

FIGS. 2, 3 and 4 are side views, with parts broken away, of certain parts of the circuit breaker mechanism illustrating relative positions of the parts during an automatic opening operation.

The invention is illustrated as applied to a circuit breaker of the type disclosed in the patent to E. A. Walker, et al., Patent No. 2,989,606, issued lune 20, 1961, and assigned to the assignee of the instant application.

Referring to FIGURE 1 of the drawings, there is shown therein the center pole unit of a three-pole circuit breaker 1. The circuit breaker 1 comprises a base 11 and a cover 13 both of molded insulating material. A stationary contact 15 and a cooperable movable contact 17 are provided for each pole of the breaker. An operating mechanism 19, common to all of the poles, is disposed in the center pole compartment. Each of the three poles is provided with a trip device 21.

The stationary contact 1S, for each pole, is rigidly mounted on the inner end of a conducting strip 23, the outer end of which is secured by means of a line terminal connector to a metal insert 26 that is seated in the base 11. The movable contact 17 is part of a movable coni 3,246,097' Patented Apr. 12, 1966 ICC tact structure indicated generally at 27 that comprises a contact arm 28 having the contact 17 secured to the outer end thereof. The contact arm 28 is pivotally secured to a switch arm 29 by means of a pin 30. The switch arm 29 comprises two identical arms having the contact arm 28 supported therebetween. The switch arm 29 is rigidly secured to an insulating tie bar 35. The tie bar 35 is rotatably supported in the sidewalls of the two outer poles. Each pole comprises a movable contact structure 27 that is rigidly secured to the common tie bar 35. Each of the contact arms 28 is biased in a clockwise direction about the associated pin 30 by means of a torsion spring 36. In each pole, a pin 37 is secured to the switch arm 29 between the twin members of the switch arm. The pin 37 is disposed in a slot 38 at the inner end of the contact arm 28 and it engages opposite ends of the slot to limit pivotal movement of the contact arm 28 about the switch arm 29. The pin 37 in the center pole unit also pivotally connects a toggle link 40 to the center-pole switch arm 29.

The toggle link 40 is part of a single operating mechanism 19 that is disposed in the center pole compartment and that comprises an inverted U-shaped operating lever 41 having its legs pivotally supported in generally V- shaped notches 43 in a pair of spaced metal frame members 45 that are mounted in the bottom portion of the base 11.

The operating lever 41 has an arcuate insulating shield 47 mounted on the outer end thereof. A handle portion 49 extends out from the shield 47 through an opening 51 in the cover 13. The switch arm 29, for the center pole unit, is operatively connected to a releasable member or cradle 57 by means of a toggle comprising the toggle link 40 and a toggle link 58. The toggle link 40 is pivotally connected to the switch arm 29 by means of the pivot pin 37. The toggle link 58 is pivotally connected to the releasable member 57 by means of a pivot pin 59. The

toggle links

40 and 58 are pivotally connected together by means of a knee pivot pin 61. The releasable member 57 is pivotally supported between the side plates 45 by means of a pivotal pin 63 that is rotatably supported on and between the side plates 45. Over center springs 67 are connected under tension between the knee pivot 61 of the

toggle

40, 58 and the yoke portion of the operating lever 41.

The contacts for all of the poles are manually opened and closed in a well-known manner by movement of the operating lever 41. When the operating lever 41 is moved from the on to the off position, the tensioned springs 67 are moved over-center with respect to the toggle 4G, 5S to cause collapse of the toggle to thereby rotate the tie bar 3S in a counterclockwise direction moving all three of the contact arm structures 27 to an open position with a snap action. When the contact arm structure 27 for the center pole unit reaches the full open position, a stop portion 70 thereon engages a stop portion 71 on the releasable member 57 to limit this opening movement. During the opening movement of the movable `Contact structure 27, the contact arm 28 moves a limited amount in a clockwise direction about the pivot 30 which movement is limited by the engagement of the pin 37 in the lower end of the slot 38 that is disposed at the inner end of the contact arm 28. The contact arm structures 27 for the two outer poles y(not shown) engage suitable stop pins disposed in the outer poles to limit the opening movement of these contact arm structures. Movement of the operating lever 41 from the off position to the on position moves the springs 67 over-center to reset the

toggie

40, 58 rotating the tie bar 35, and therefore the three movable contact structures 27, in a clockwise direction `to the closed position with a snap action. When the movable contact structures 27 are in the closed position (FIG. l) each of the contact arms 23 is rotated slightly in the clockwise direction about the pin 30 to thereby permit the associated torsion spring 36 to bias the associated contact arm 23 into the fully closed position. Thus, independent resilient contact pressure means is provided in each ot the pole units of the circuit breaker.

The contacts are opened automatically, in response to an overload current occurring in any pole of the circuit breaker, by release of the releasable member 57. The member 57 is normally releasably restrained in operative position by means of a latch mechanism indicated generally at 72, which latch mechanism is actuated by the trip device 21. When released, the member 57 is rotated in a clockwise (FIG. 1) direction about its pivot 63 by the torce of the discharging tensioned over-center springs 67 causing collapse of the

toggle

40, 58 and opening movement of all of the movable contact structure 27 in a manner to be hereinafter specifically described.

The latch mechanism 72 comprises a main latch 73 pivoted on a pin 75 that is supported between the sfde plates 45. The main latch 73 is biased in a clockwise unlatching direction by means of a torsion spring 77. The main latch 73 is provided `with a latching portion 79 that engages a latch tip 81 on the free or latching end ot the releasable member 57 to releasably hold the member 57 in operative position. The latch tip S1 is in-turned in the direction toward the pivot 63 about which it moves. The latch 73 is of the slip-oit type and is releasably held in latching position by a latch which comprises a rotary shaft or ro-d 83 that is rotatably mounted between the side plates 45. The latch rod 83 has a cut-out portion or notch (not shown) provided therein. A part 86 of the latch 73 engages the periphery of the shaft 83 just above the notch. The latch 83 has an upwardly extending arm 89 secured thereto which, at its upper end, has an ear 91 formed thereon. An adjusting screw 93 is -threaded into the ear 91 and is rotated to an adjusted position in engagement with a projection 97 on an insulating trip bar 99. A spring 100 biases the arm 89 and the shaft 33 to the latching position seen in FIGURE 1.

The trip bar 99 is rotatably supported by means of pins 101 molded at the opposite ends thereof, which -pins are rotatably supported in the sidewalls of the circuit breaker housing. The trip bar 99 is provided with a downwardly extending projection 105 in each pole unit. In each pole unit, an ambient temperature compensating bimetal element 107 is rigidly mounted on the projection 105 and is adapted to be mechanically actuated by the trip device 21 in the associated pole.

The tri-p device 21 for each pole comprises a tripping bimetal element 109 that is supported on a conductor 111 that is mounted on a metallic insert 113 which insert is secured in the base 11 during the molding operation of 4the base. The conductor 11 is secured on the insert 113 by means of a screw 115 that also secures a xed magnetic member 117 and a terminal 119 on the base. A calibrating or adjusting screw 121 is supported on a conducting tab 122 that is secured to the upper end of the bimetal 109. Upon thermal bending of the bimetal 199 in respouse to low overload currents, the screw 121 engages the free or upper end of the compensating bimetal 107 to rotate the trip bar 99 in a clockwise direction about the pivot 101. A magnetic member or armature 123 is rigidly secured to the tripping bimetal element 109 adjacent the upper end of the tixed magnetic member 117 and on the side of the bimetal 109 that is opposite the side that faces the magnetic member 117. The armature 123 is attracted to the xed magnetic member 117 in response to excessive overload currents tlowing through the bimetal 109 whereupon the tripping bimetal 109 is bent to the right to ettect instantaneous operation of the trip bar 99.

In each pole, a flexible conductor 125 is connected at one end to the associated terminal 119 and at the other end to the associated contact arm 28. In each pole, a

flexible conductor 129 is connected at one end to the conducting tab 122 and at the other end to a conducting strip 131.

In each pole, the circuit extends from the conductor 131 through the conductor 129, the tab 122, the bimetal 109, the conductor 111, the conductor 119, the flexible conductor 125, the contact arm 28, the

contacts

17, 15 to the Conductor 23. The conducting strip 131 for each pole is provided at its outer end with a load terminal connector 133 that is threadedly supported in a metallic i11- sert 134i that is seated in the base 11.

The high expansion sides of the tripping bimetal element 11,19 and the compensating bimetal element 107 are both on the left side of the bimetal elements as seen in FIGURE 1. Thus, the bimetal elements will simultaneously deliect in the -same direction in response to changes in ambient temperature to thereby compensate for thermai reaction of the tripping bimetal element 109 in response to changes in the ambient temperature.

When a low persistent overload current below a predetermined value occurs in any ot the pole units, the actuating bimetal 109 in the overloaded pole unit becomes heated and bends to the right. During this movement, the screw 121 is moved to move the compensating bimetal 107 to thereby pivot the trip bar 99 clockwise whereupon the projection 97 on the trip bar, engaging the adjusting screw 93, rotates the arm S9 and rotary latch S3 clockwise to a position where the portion 86 of the main latch 73 falls into the notch (not shown) in the latch 83. rhis clockwise unlatching movement of the latch 73 frees the latch portion 81 of the member 57 to release the member 57. The latching point 79 of the main latch 73 and the latch portion $1 of the member 57 are to the left of the pivot 75 so that the main latch 73 is biased in the unlatching direction by a component of the force exerted by the over-center springs 67. Thus, when the main latch 73 is released, it is immediately snapped to the unlatching position releasing the member 57.

When the member 5'7 is released, the tension springs 67 operate through the knee pivot 61, the toggle link 5S and the pin 59 to exert a force on the member S7 rotating the member 57 about the pivot 63. During this movement, the lever 41, springs 67, toggle 40, 5S, and movable contact structure 27 are moved to position these parts such that the springs 67 are over-center on the lett of the toggle 40, 5S whereupon the springs 67 pull the kneepivot 61 upward collapsing the toggle 40, 5i; and rotating the center-pole movable contact structure 27 counterclockwise, which movement, through the common tie bar 35, rotates all of the movable contact structures 27 counterclockwise to the open position with a snap action.

Improved means are provided for arresting rebound ot' the movable Contact structures 27 during an automatic opening operation. Referring to FIGS. 2-4, as the movable contact structure 27 tor the center pole unit appreaches the fully opened position, the Contact arm at 137 engages a projection 139 that is formed integrally with the releasable member 57. During the automatic opening operation, the discharging springs 67 operate through the

toggle

40, 58 to rotate the releasable member 57 in a clockwise direction, and at the same time the springs operate to collapse the

toggle

40, 58 to thereby rotate the movable contact structure in a counterclockwise opening direction. The opening movement of the movable Contact structure 27 is highly accelerated by the magnetic blow-off forces that are generated by the overload current that is being interrupted. Thus, when the contact arm at 137 engages the projection 139 (FG. 2) of the releasable member 57, the clockwise movement of the member 57 is stopped and the member 57 is thereafter moved in a counterclockwise direction to the position seen in FG. 3. Since the member 57 is stopped and thereafter moved counterclockwise against the spring force that tends to rotate this member clockwise, this action operates to decelerate opening movement of the movable contact structure 27 to thereby arrest rebound of the movable contact structure. In this embodiment the part 70 of the contact arm 28 engages the part 71 of the releasable member 57, and since the opening force of the movable contact structure 27 operates at 71 through the pivot 63 of the member 57, the part 71 of the member 57 serves as a iinal stop preventing further counterclockwise movement of the movable Contact structure 27.

During an automatic opening operation, the parts move from the FIGURE 1 position to the FIG. 2 position wherein the movable contact structure 27 engages the part 139 of the releasable member 57 to decelerate move ment of the movable contact structure 27. During this movement the springs 67 also tend to rotate the lever 41 counterclockwise which movement is limited by the engagement of a tail part 143 on the lever 41 with a shoulder 14S on the releasable member 57 and by the engagement of the bight portion 147 of the generally U-shaped lever 41 with a stop portion 149 on the releasable member 57. The parts then move to the FIG. 3 position where, in this embodiment, the part 70 of the movable contact structure 27 engages the part 71 of the releasable member 57 to limit opening movement of the movable contact structure 27. During this movement, the part 147 of the lever 41 moves away from the part 149 of the member 57 a small distance while the part 143 of the lever 41 slides against the shoulder 145 of the member 57. In the FIG. 3 position the system is ready to dissipate the potential energy contained in the springs 67 at the natural frequency of vibration of this mechanical system.

FIG. 4 illustrates the stopped position of the parts after an opening operation. The component of spring force acting to rotate the member 57 clockwise is stronger than the component of spring force acting to rotate the movable contact structure counterclockwise. Thus, the member 57 rotates clockwise until it is stopped when the part 149 thereon engages the part 147 of the lever 41. 'This engagement of the

parts

149 and 147 stops all of the parts in the FIG. 4 position with the lever 41 being so positioned that the handle 49 (FIG. 1), that is attached thereto, is in an intermediate position between the on and off positions. Thus, the mechanism is constructed to provide a visual indication that the circuit breaker has tripped.

As was previously described, the circuit breaker 1 is a three-pole circuit breaker comprising only one operating mechanism 19 disposed in the center pole compartment. Thus, only the movable contact structure 27 in the center pole engages the tail portion 139 of the single releasable member 57 to decelerate movement of the movable contact structure during lan automatic opening operation. Since all of the movable contact structures 27 are connected to the common tie bar 35, this decelerating movement of the movable contact structure in the center pole operates to decelerate movement of all of the movable contact structures in all three of the pole units. As was previously described, during a manual operation the contact arm structures 27 for the two outer pole units (not shown) engage suitable stop pins disposed in the outer pole units to limit counterclockwise movement of these contact arm structures. During an automatic opening operation, the contact arm structures for the two outer poles engage the same stop pins disposed in the outer poles to limit counterclockwise movement of these contact arm structures.

Before the breaker contacts can be closed following an automatic opening operation, it is necessary to reset and relatch the mechanism. This is accomplished by moving the handie 49 counterclockwise to the full ofi position. During this movement, the tail portion 151 on the operating lever 41 slides against the shoulder 149 of the releasable member 57 to thereby move the releasable member 57 counterclockwise about its pivot 63. Near the end of this movement, the lower rounded portion of the latch end 81 of the member 57 engages an outwardly extending arm of the bell-crank latch member 73 to move the latch member 73 counterclockwise. As the latch part 86 of the latch member 73 clears the corner of the notch (not shown) in the latch rod 83, the spring 10i! restores the arm S9 to its normal position moving the latch 83 to its latching position. During this movenient, the latching portion 79 of the latch "/3 is moved above the latch end 81 of the releasable member S7 `and the latch 73 is restrained in this latching position by engagement of the part 86 thereon with the periphery of the rotary latch rod 83. Thus, when the handle 49 is released, the latch part 81 of the releasable member 57 will engage the latch part 79 of the latched main latch 73 and the structure will be latched in the position seen in FIGURE l.

Upon the occurrence of an excessive overload or short circuit current above the predetermined value, the armature 12.3 (FIG. l) will be attracted to the Xed magnetic member 117 bending the bimetal 169 to the right (FIG. 1) instantaneously to thereby etlect an instantaneous tripping operation of the circuit breaker in the same manner hereinbefore described.

In the preferred embodiment, the mechanism is constructed such that the part 70 of the contact arm 2S engages the part 71 of the member 57 to limit counterclockwise movement of the movable contact structure 27 during an opening operation. The parts 70, 71 deform slightly at each Contact to absorb energy from the mechanical system. The mechanism can be constructed without the stop means 70, 71, in which case the component of spring force acting to rotate the member 57 clockwise will limit counterclockwise movement of the movable contact structure 27 This can be done, for example, by cutting ott portions of the

members

57 and 28 in the regions of the stops 71 and 70. The component of spring force acting to rotate the member 57 clockwise is of such strength that, with the elimination of the stop means 70, 71, the movable contact structure 27 will move counterclockwise only a slight distance further than the distance shown in FIG. 3 before the component of spring force acting to rotate the member 57 clockwise will limit this counterclockwise movement of the movable contact structure 27. In all other respects the mechanism without the stop means 70, 71 will operate in the same manner hereinbefore described.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the illustrated structural details and arrangement of parts may be made without departing from the spirit and scope of the invention.

We claim as our invention:

1. A circuit breaker comprising a stationary contact, a movable Contact structure cooperable with said stationary contact to open and close an electric circuit, an operating mechanism connected to said movable cont-act structure for operating said movable contact structure, said operating mechanism comprising a latched releasable member and resilient means, means operating upon the occurrence of certain overload current conditions to release said releasable member whereupon said resilient means operates to move said releasable member in a lirst direction to effect a change of the line of action of said resilient means whereupon said resilient means operates to move said movable contact structure to an open position, means on said releasable member to engage said movable contact structure and to move with said movable contact structure in a direction opposite said iirst direction to decelerate opening movement of said movable contact structure during said opening movement of said movable Contact structure.

2. A circuit breaker comprising a stationary contact, a movable contact structure cooperable with said stationary contact to open and close an electric circuit, an operating mechanism connected to said movable contact structure for operating said movable contact structure, said operating mechanism comprising a latched releasable member and over-center spring means, means operating upon the occurrence of certain overload current conditions to release said releasable member whereupon said over-center spring means operates to move said releasable member in a first direction to effect a change of the line of action of said over-center spring means whereupon said over-center spring means operates to move said movable contact structure to an open position, means on said releasable member to butt against said movable Contact structure and to move with said movable contact structure in -a second direction opposite said rst direction against force exerted by said over-center spring means to thereby decelerate opening movement of said movable Contact structure during said opening movement of said movable contact structure.

3. A circuit breaker comprising a stationary contact structure, a movable contact structure cooperable with said stationary contact structure to open and close an electric circuit, an operating mechanism connected to said movable contact structure for operating said movable contact structure, said operating mechanism comprising a latched releasable member supported on a iixed pivot, over-center spring means supported under tension, trip means operating upon the occurrence of certain overload current conditions to release said releasable member whereupon said over-center spring means operates to pivot said releasablc spring member in a first direction to thereby change the line of action of said over-center spring means whereupon said over-center spring means operates to move said movable Contact structure to an open position, means on said releasable member to engage said movable contact structure with a butt type engagement and to move with said movable contact structure in a second direction opposite said first direction to thereby dampen said opening movement of said movable contact structure, and stop means engaged by said movable contact structure to limit movement of said movable contact structure in the opening direction.

4. A circuit breaker comprising a stationary contact structure, a movable Contact structure cooperable with said stationary contact structure to open and close an electric circuit, a latched releasable member, a toggle connected at one end to said movable contact structure and at the other end to said releasable member, an operating member, over-center spring means supported between said operating member and said toggle, when said releasable member is latched to said operating member being manually operable to operate said over-center spring means and said toggle to thereby operate said movable contact structure to open and closed positions, trip means operating upon the occurrence of certain overload current conditions to release said releasable member whereupon said over-center spring means operates to pivot said releasable member in a lirst direction to change the line of action of said over-center spring means whereupon said over-center spring means operates said toggle to move said movable contact structure to an open position, means on said releasable member to engage said movable contact structure with a butt-type engagement to stop said movement of said releasable member in said iirst direction and to thereafter move with said releasable member and said movable contact structure in -a second direction opposite said first direction against a torce exerted by said over-center spring means to thereby decelerate opening movement of said movable contact structure.

5. A circuit breaker comprising a stationary contact structure, a movable contact structure cooperable with said stationary Contact structure to open and close an electric circuit, a latched releasable member, a toggle connected at one end to said movable contact structure and at the other end to said releasable member, an operating member, over-center spring means supported between said operating member and said toggle, when said releasable member is latched said operating member being manually operable to operate said over-center spring means and said toggle to thereby operate said movable contact structure to open and closed positions, trip means operating upon the occurrence of certain overload' current conditions to release said releasable member' whereupon said over-center spring means operates to pivotV said releasable member in a tirst direction to etlect a'. change of the line of action of said over-center spring means whereupon said over-center spring means operatesy said toggle to move said movable contact structure to anv open position, means on said releasable member to engage said movable Contact structure during said opening movement to stop said pivotal movement of said releasable member in said first direction and to thereafter move with said releasable member and said movable contact structure in a second direction opposite said iirst direction to thereby dampen opening movement of said movable contact structure, and stop means on said releasable member to engage said movable contact structure to limit said movement of said movable contact structure in the opening direction.

6. A circuit breakercomprising a stationary contact structure, a movable Contact structure cooperable with said stationary contact structure to open and close an electric circuit, a latched releasable member, an operating member, spring means connecting said operating member said movable contact structure and said releasable member, trip means operable to unlatch said releasable member, when said releasable member is latched said operating member being movable from an on position to an oft position to operate said spring means to move said movable contact structure to an open position and said operating member being movable from said oli position to said on position to operate said spring means to move said movable contact structure to a closed position, when said releasable member is latched and said operating member is in said on position and. an overload current above a predetermined value occurs in the circuit of the breaker said trip means operating automatically to release said releasable member whereupon said spring means operates to move said releasable member in a first direction to change the line of action of said spring means whereupon said spring means operates to move said movable contact structure to an open position and to move said operating member toward the ofi position, means on said releasable member to engage said movable contact structure with a butt-type engagement to stop said movement of said releasable member in said first direction and to thereafter move with said releasable member and with said movable contact structure in a second direction opposite said rst direction against a force exerted by said spring means to thereby decelerate said opening movement of said movable contact structure, and means on said operating member to engage means on said releasable member to stop said operating member in a position between said on and off positions to thereby provide a visual indication that said circuit breaker has been automatically opened.

7. A circuit breaker comprising an insulating housing having an opening therein, a circuit breaker mechanism supported within said housing and comprising an external handle extending through said opening, said circuit reaker mechanism comprising an operating member connested 'to said handle, a stationary Contact structure, a movable contact structure cooperable with said stationary contact structure to open and close an electric circuit, a latched releasable member, a toggle connected at one end to said movable contact structure and at the other end to said releasable member, spring means connected at one end to said operating member and at the other end to said toggle, trip means, when said releasable member is latched said handle being movable from an on position to an ott position to move said operating member and said spring means to operate said toggle to thereby operate said movable contact structure to an open position and said handle being movable from said oi position to said on position to move said operating member and said spring means to operate said toggle to move said movable Contact structure to the closed position, when said releasable member is latched and said handle is in said on position and an overload current above a predetermined value passes through the circuit of said breaker said trip means operating automatically to release said releasable member whereupon said spring means operates to move said releasable member in a first direction to change the line of action of said spring means whereupon said spring means operates said toggle `to move said movable Contact structure to an open position and a component of the force of said spring means operates to move said operating member and said handle toward the oit position, means on said releasable member to engage said movable contact structure and to thereafter move in a second direction opposite said first direction with said movable Contact structure against a component of the force of said spring means to thereby decelerate opening movement of said movable contact structure, stop means on Said releasable member to engage means on said movable contact structure to limit movement of said movable Contact structure in the opening direction, and means on said operating member to engage means on said releasable member to stop the movement of said operating member releasable member and movable contact structure with said operating member being stopped in a position such that said handle is between said on and off positions to thereby provide an external visual indication that said circuit breaker has been automatically opened.

References Cited by the Examiner UNITED STATES PATENTS 2,989,606 6/1961 Walker et al 2SC-116 X 3,003,046 10/1961 De Torre 200--116 X 3,134,879 5/1964 Gauthier et al. 200--169 BERNARD A. GLHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

T. D, MACBLAIN, Assistant Examiner.

Claims

1. A CIRCUIT BREAKER COMPRISING A STATIONARY CONTACT, A MOVABLE CONTACT STRUCTURE COOPERABLE WITH SAID STATIONARY CONTACT TO OPEN AND CLOSE AN ELECTRIC CIRCUIT, AN OPERATING MECHANISM CONNECTED TO SAID MOVABLE CONTACT STRUCTURE FOR OPERATING SAID MOVABLE CONTACT STRUCTURE, SAID OPERATING MECHANISM COMPRISING A LATCHED RELEASABLE MEMBER AND RESILIENT MEANS, MEANS OPERATING UPON THE OCCURRENCE OF CERTAIN OVERLOAD CURRENT CONDITIONS TO RELEASE SAID RELEASABLE MEMBER WHEREUPON SAID RESILIENT MEANS OPERATES TO MOVE SAID RELEASABLE MEMBER IN A FIRST DIRECTION TO EFFECT A CHANGE OF THE LINE OF ACTION OF SAID RESILIENT MEANS WHEREUPON SAID RESILIENT MEANS OPERATES TO MOVE SAID MOVABLE CONTACT STRUCTURE TO AN OPEN POSITION, MEANS ON SAID RELEASABLE MEMBER TO ENGAGE SAID MOVABLE CONTACT STRUCTURE AND TO MOVE WITH SAID MOVABLE CONTACT STRUCTURE IN A DIRECTION OPPOSITE SAID FIRST DIRECTION TO DECELERATE OPENING MOVEMENT OF SAID MOVABLE CONTACT STRUCTURE DURING SAID OPENING MOVEMENT OF SAID MOVABLE CONTACT STRUCTURE.