US2467797A - Circuit breaker - Google Patents

Description

April 19, 1949. E. G. WISE CIRCUIT BREAKER Filed July 24, 1943 & BY 71/ ATTORNEY WITNESSES:

Patented Apr. 19, 1949 CIRCUIT BREAKER.

Ernest G. Wise, St. Louis, Mo., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 24, 1943, Serial No. 495,975

32 Claims. 1

The invention relates to circuit breakers and more particularly to manually and automatically operable small air circuit breakers for controlling and protecting electrical circuits.

An object of the invention is the provision of a double-throw circuit breaker having contact means for controlling two circuits, and operating mechanism manually operable to selectively operate said contact means to open or close either circuit and automatically operable in response to predetermined overload conditions to cause opening of the contact means.

Another object of the invention is the provision of a circuit breaker having contact means for selectively controlling either of two circuits and a single operating mechanism that is automatically operable in response to predetermined abnormai circuit conditions in whichever circuit is closed to cause automatic opening of said contact means.

Another object of the invention is the provision of a circuit breaker as described in the two preceding paragraphs, the breaker having an operating handle operable in either direction from a central open position to selectively close one or the other of two circuits and the handle being operable by a releasable actuator in response to overload currents in the closed circuit to effect opening of the circuit.

Another object of the invention is the provision of a circuit breaker having an improved operating mechanism which is operable to selectively close one or the other of two circuits, and

- tripping means operable in response to overload currents in the selectively closed circuit to effect automatic opening of said circuit.

Another object of the invention is the provision of a circuit breaker having an operating mechanism including an operating handle and contact means operated thereby for selectively closing any one of a plurality of circuits, and having a releasable means controlled by a trip device for causing automatic opening of the contact means in response to predetermined overload conditions.

Another object of the invention is the provision of a manually and automatically operable circuit breaker mechanism of compact and lowcost construction which can be used either as a double-throw circuit breaker for selectively controlling either of two circuits or as a singlethrow circuit breaker for controlling a single circuit.

Another object of the invention is the provision of an improved circuit breaker construction that 2 is simple, reliable in operation and relatively inexpensive to manufacture.

The novel features that are considered characteristic of the invention are set forth in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of one embodiment thereof when read in connection with the accompanying drawing, in which:

Fig. l is a vertical sectional view of a circuit breaker embodying the principles or the invention, the switch arm being shown in engagement with one of the stationary contacts.

Fig. 2 is a vertical transverse sectional view through the breaker taken substantially on line II-II of Fig. i.

Fig. 3 is a vertical sectional view of the breaker showing the breaker mechanism in the open A position.

Referring to the drawing, the circuit breaker is mounted in a housing comprising a base portion II of molded insulating material having side walls l3, and a cover plate I5 also of insulating material. The circuit breaker comprises, in general, stationary contacts l1 and I9, movable contacts 2i and 23 adapted to cooperate respectively with the stationary contacts I! and I9, operating mechanism indicated generally at 25 and a trip device 21.

The stationary contact I1 is rigidly mounted on a conductor 29 secured to the base H by means of a screw 3| which also secures a load terminal 33 to the base. The stationary contact i9 is similarly rigidly supported on a conductor 35 secured to the base H by means of a screw 31, which also serves to secure a load terminal 39 to the base. The terminals 33 and 39 serve to connect the stationary contacts I! and I9 to their respective electrical load circuits. The movable contacts 2i and 23 are rigidly mounted on opposite sides of the inner end of a V-shaped switch arm 4| of conducting material (Fig. 2), each leg of which is provided with a projection 43. The projections 43 engage V-shaped recesses '45 in the spaced sides of a U-shaped frame 41 secured by means of screws 49 to the base H and by a screw 50 to one end wall of the housing. Pivotally supported on a pivot pin 51 mounted in the side walls I3 of the housing is an operating handle 53 projecting outwardly through an Opening 54 in the cover plate l5. The inner end of the handle 53 is U-shaped and each leg 55 thereof is provided with an elongated slot through which extend the ends of a pin 59. The pin 59 is supported on spaced links 6| pivotally mounted on pins 62 which are supported in the two sides of the frame 41 as shown in Fig. 2. The pin 59 which engages the slots of the handle is connected by means of an overcenter spring 63 to the apex of the V-shapecl switch arm 4| (Fig. 2).

When the handle 53 is in the on position shown in Fig. 1, the overcenter spring 53 biases the links 6| in a counterclockwise direction and the links 6| are restrained by the spring in the position shown by engagement of the pin 59 with the inner ends of the slots 51. As shown in Fig. 1, the spring 63 biases the movable contact 2| into engagement wlfl the stationary ,contact I] and provides the essential contact pressure for the closed contacts. A component of the force of the spring 63 biases the switch arm 4| outwardly in the direction of its length. With the handle 53 in the "on position shown in Fig. 1, outward movement of the switch arm is prevented by engagement of the projections 43 on the switch arm 4| with the edge of an actuator 65 pivotally supported on a pivot pin 61 mounted in the sides of the frame 41. The actuator 65 comprises two spaced actuator members mounted on the pin 51 and disposed one on the outside of each side of the frame 41. The two actuator members 65 are rigidly connected by shouldered pins 69 and 1| for unitary pivotal movement and are biased for clockwise rotation about the pivot pin 61 by means of a relatively strong spring 13 coiled about the fixed pin 61 and having the bight of the spring hooked under the pin 69, the two ends of the spring bearing against the connecting portion of the U-shaped frame 41.

The actuator 65 is normally releasably restrained in operative position (Fig. 1) by means of the trip device 21 which comprises a bimetal element 15. The bimetal element 15 has one end rigidly secured to an angular conductor 'li which is secured to the base H by a screw 19. The screw 19 also serves to secure a supply line terminal 8| to the base. The terminal 8| serves to connect the breaker to the supply line of an electrical circuit. The bimetal element 15 is connected by means of a flexible shunt conductor 82 to the switch arm 4|. When the contacts I!- 2| are closed the circuit through the breaker extends from the supply line terminal 8| over the screw 79, conductor TI, bimetal element 15, the flexible shunt conductor 82, switch arm 4|, contacts ||--2|, conductor 29, and screw 3| to the load terminal 33. When the contacts |9-23 are closed the circuit extends from the supply line terminal 8|, screw 19, conductor 11, bimetal l5, flexible shunt conductor 82, switch arm 4| (in the position indicated at No), contacts Ill-- 23, conductor 35, and screw 3'! to the other load terminal 39. A latch 83 on the bimetal 15 nor mally engages the latching end 85 of the actuator 65 in order to restrain the actuator in operative position.

With the actuator 65 restrained in the operative position (Fig. 1) and the operating handle in the full line position, it will be seen that the spring 63- is overcenter to the left of the pivot 62 0f the links 6|, and to the left of the point of engagement of the switch arm 4| with the actuator 65. In this position the spring biases the contacts ||2| closed-and biases the projections 43 again-it the under edges of actuator 65.

Upon the occurrence of an overload current in the circuit including the contacts |'|--2|, the bimetal element 15, when heated a predetermined amount by the overload current, deflects toward the left and releases the actuator 65 which is immediately rotated in a clockwise direction by means of the. spring 73. The configuration of the outer edges of the actuators is such that they engage the inner ends of the legs 55 of the handle and cam the handle counterclockwise from the full line position (Fig. 1) to the central ofF position (Fig. 2) where the legs 55 engage locating recesses 81 in the actuator members. The recesses 81 cooperate with the legs 55 to hold the handle 53, the links 6! and the overcenter spring 63 in the central off position. As the handle moves to the off position from either of its on" positions, the links 6|, due to the pin and slot connection 595l, are rotated to the position in which they are shown in Fig. 3. Since the outer end of the spring 63 is attached to the pin 59 the line of action of the spring will be moved closer to the center line of the switch arm 4| so that a greater component will be applied to the switch arm tending to move said switch arm longitudinally away from the base of the breaker. As the actuator 55 moves the handle to the oil position, it also moves in a clockwise direction away from the throats 9| of the recesses 89 at the apex of the recesses 45 in the frames 47', thereby permitting longitudinal movement of the switch arm 4|. As the projections 43 of the switch arm 4| enter the recesses 89 (see Fig. 4) the outer ends of the projections engage curved cam surfaces which, due to the action of the spring 63, as the line of action of the spring ap-- the projections enter the recesses 89, and that the full thickness of the projections engages the throat 9| with but a slight clearance to retain the switch arm in the ofi position.

The automatic opening operation of the circuit breaker is the same from either of the closed positions. When the handle 53 is in the on position indicated by dotted lines at 53a (Fig. 1), the spring 33 biases the switch arm 4| to the position 4 la wherein the contacts |9-23 are closed. When the bimetal i5 deflects, in response to an overload current and releases the actuator, the handle 53 is cammed in a clockwise direction to the central foflf position moving the line of action of the spring 63 closer to the center line of the switch arm 4| in the dotted position 4|a, whereby a greater component of the force of the spring is applied to move the switch arm longitudinally outwardly. As the actuator 65 moves away from the throats 9| of the recesses 99, the spring moves the tapered ends of the projections 43 into the recess 89 and actuates the switcharm to the open position shown in Fig. 3, the action being the reverse of that described for the auto-.

lowing an automatic opening operation by a single manual movement of the handle 53 from the central off position in either direction slightly beyond either of the 011" positions: During this movement, the inner ends of the legs 58 of the handle cam the actuator members 65 counterclockwise. Near the end of the counterclockwise movement of the actuator, the latching end 85 thereof wipes by the latch 83 which, due to the resiliency of the bimetal 15, immediately resumes its latching position. Upon re,- lease of the handle the spring 13 rotates the actuator 65 slightly in a clockwise direction until it is arrested by engagement of the latching end 35 thereof with the latch 83. In order to permit the slight overtravel of the handle to effect relatching of the actuator, the links 6| are eachprovided with an elongated slot engaging the pin 02. During the overtravel which is necessary in order to reset the actuator, the slots in the links ll move over the pins 62, and, upon release of the handle, the spring 63 moves the links 6| inwardly until the upper ends of the slots rest on the pivot pin 62.

During the counterclockwise rotation of the actuator 65 effected by movement of the handle in either direction from the central off posi- When the handle is moved to the central 0 position from either of its "021 positions, the inner end of one of the legs 55 of the handle engages and straightens the spring 91 as shown in Fig. 3. Since the one end of the spring is held by the pin 99 against longitudinal movement, the other end of the spring is moved toward the left and engages and moves the free end of the bimetal in a direction to release the actuator 35. The spring 13 then moves the actuator 65 to permit movement of the switch arm to open position into the recesses 83 in the manner previously described for the automatic opening of the contacts.

tion to one of the on positions, the inner edges thereof engage the ends of the projections 43 and thrusts the switch arm 4| inwardly out of the recesses 89. As the handle 53 is moved to one of its on positions, the links 6!, due to the pin and slot connection 59--51, are rotated to carry the outer end of the spring 63 to the right or left, depending upon the direction the handle is moved. Assuming that the handle is rotated clockwise from the Fig. 3 position to the Fig. 1 position, the links 6| will be rotated counterclockwise carrying the outer end of the spring 63 to the left away from the center line of the switch arm. This causes the spring to apply a greater biasing force to the switch arm biasing it in a clockwise direction. As the movement of the handle continues and the movement of the actuator continues the biasing force of the spring biasing the switch arm in a clockwise direction continues to increase until the ends of the proiections 43 are clear of the recess 89, whereupon the spring 63 rotates the switch arm to close the contacts I 1--2l with a snap action. Resetting of the actuator and closure of the contacts I923 is effected in the same manner except that the movement of the parts, other than the actuator 65 are reversed.

In order to open the contacts either automatically or manually, it is necessary to permit the projections 43 of the switch arm 4| to move into the recesses 89, and in order to effect this movement of the switch arm it is necessary that the actuator 65 be released and moved out of the way. On automatic operations the actuator 65 is released by the bimetal element as previously described. Means is provided to effect release of the actuator when the contacts are opened manually. This means comprises a spring member 91 having one end supported on a pin 99 rigidly mounted in one side wall of the casing and extending inwardly therefrom through a clearance opening llll in the actuator member 65 disposed adjacent thereto. The spring 91 is given an initial arcuate shape, as shown in Fig. 1. The other end of the spring 91 extends between spaced guide pins |03 and is disposed close to one side of the free end of the bimetal element 15.

Following a manual opening operation the actuator can be manually reset and either set of contacts closed in the previously described manner.

From the foregoing description, it will be seen that there is provided a simple double-throw circuit breaker having a single operating mechanism for selectively closing either one of two circuits, each of said circuits, when closed, being protected against overload currents by the provision of an overload trip device.

The circuit breaker structure can also be used as a single-throw circuit breaker to control a single circuit, if desired, by using only one of the load terminals 33 or 39.

Having described the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the structural details thereof without departing from some of the essential features of the invention.

I claim as my invention:

1. A double-throw circuit breaker for selectively controlling either one of two circuits comprising a switch member having an open position and movable in either direction to closed positions for selectively closing said circuits, an operating handle having a central open position and movable in either direction from said open position to closed positions, means comprising an overcenter spring operable by said handle for moving said switch member in either direction from the central open position to selectively close said circuits with a snap action, a member operable to actuate said overcenter spring to effect automatic opening movement of said switch memher from either of its closed positions, and a trip device operable in response to overload currents in either of said circuits to cause automatic operation of said member.

-2. A circuit breaker for selectively controlling either one of two circuits'comprising two sets of separable contacts, a switch member having two closed positions in which one or the other of said sets of contacts are closed, said switch member being movable from said closed positions to a central open position, a supporting frame having a recess into which said switch member is longitudinally movable to said open position, a releasable member normally preventing movement of said switch member into said recess and operable when released to permit said switch member to move into said recess, and a trip device operable in response to overload currents to release said releasable member and thereby permit movement of said switch member into said recess.

3. A circuit breaker for selectively controlling either one of two circuits comprising a frame having a recess therein, two sets of contacts, a. switch member having two closed positions in which said sets of contacts are closed and having an open position, said switch member being adapted to move into said recess to said open position, a releasable member normally preventing movement of said switch member into said recess, said releasable member being operable when released to permit said switch member to move into said recess to the open position, electro-responsive means operable in response to overload currents in whichever circuit is closed to release said releasable member to thereby efifect automatic opening of the corresponding set of contacts, and manual means operable to release said releasable member.

4. A circuit breaker for selectively controlling either one of two circuits comprising a supporting frame having a recess therein, two sets of contacts, a switch member having an open position and movable in either direction from said open position to selectively close said contacts, operating mechanism including an operating handle for manually operating said switch member to open and to selectively close said contacts, said switch member being movable into said recess to the open position, a releasable actuator normally restraining said switch member from entering said recess, said actuator being operable when released to operate said handle to open position and to permit movement of said switch member into said recess, a trip device operable in response to overload currents to release said releasable member, and means operable by said handl for operating the trip device to release said actuator.

5. A circuit breaker for selectively controlling either one of two circuits comprising two sets of separable contacts, operating means therefor comprising a handle and a spring operable by said handle to open and to selectively close said sets of contacts, said spring biasing said contacts closed in each of said closed positions, and electroresponsive means operable in response to predetermined overload currents in whichever circuit is closed to cause automatic opening of said sets of contacts.

6. A circuit breaker for selectively controlling either one of two circuits comprising spaced rigidly mounted stationary contacts, a switch member having contact means rigidly mounted thereon and having a central open position, said switch member being movable in each direction from said central open position to close said circuits, operating means therefor comprising a manual handle and a spring operable thereby to manually move said switch member to said open position and to selectively engage said switch member with said stationary contacts, said spring biasing said contacts closed in each closed position, a releasable trip member for operatin said spring to cause automatic opening of said contacts, and electroresponsive means operable in response to predetermined overload currents to release said trip member, said handle when operated to selectively close said contacts resetting said trip member.

7. A circuit breaker for selectively controlling either one of two circuits comprising spaced rigidly-mounted stationary contacts, a switch member having a central open position and movable in each direction therefrom to close said circuits, movable contact means rigidly mounted on said switch member for co-operating with said stationary contacts, operating means for said switch member comprising a manual handle and a spring operable thereby for selectively engaging said movable contact means with said stationary contacts and also for moving said switch means to said open position, said spring biasing said contacts closed in each closed position of said switch member, a releasable trip member operable when released to cause automatic movement of said switch member to open position, and a trip device operable in response to overload currents in whichever circuit is closed to release said trip member, said handle when moved to selectively close said circuits resetting said trip member.

8. In a circuit breaker for selectively controlling either one of two circuits comprising spaced stationary contacts, switch means operable to open and to selectively close said circuits, operating mechanism comprising a handle for operating said switch means to manually open and selectively close said circuits, 9. spring connected at one end to be moved upon movement of said handie and connected at the other end to cause move= ment of said switch means and said spring biasing the switch means closed in both closed positions, and electroresponsive means operable in response to overload currents in whichever circuit is closed to cause automatic opening movement of said switch means.

9. In a circuit breaker for selectively controlling either one of two circuits comprising a pair of stationary contact means, a. single switch member having contact means rigidly mounted thereon operable to open and to selectively close said-circuits, an operating handle for effecting manual opening and closing of said circuits, spring means through which movement of said handle is transmitted to said switch member and acting to bias said switch member closed in both closed positions, and thermally responsive means operable in response to overload currents in whichever circuit is closed to cause automatic opening movement of said switch member.

10. In a circuit breaker for selectively controlling either one of two circuits comprising a pair of spaced stationary contacts, switch means operable to open and selectively close said circuits, operating mechanism comprising a handle for operating said switch means to manually open and selectively close said circuits, said stationary contacts both being disposed substantially in line with the plane of movement of said handle, a spring biasing said switch means closed in both closed positions, and electroresponsive means operable in response to overload currents to cause automatic opening movement of said switch means.

11. In a circuit breaker for selectively controlling either one of two circuits comprising a. I

pair of stationary contacts, a single switch member operable to open and selectively close said circuits, operating mechanism comprising a handle for operating said switch member to manually open and selectively close said circuits, said stationary contacts and said switch member being disposed substantially in the plane of movement of said handle, a spring connected at one end to be moved upon movement of said handle and connected at the other end to cause movement of the switch member and said spring biasing the switch member closed in both closed positions, and electroresponsive means operable in response to overload currents in whichever circuit is closed to cause automatic opening movement-of said switch member.

12. In a circuit breaker for selectively controlling either one of two circuits comprising spaced stationary contacts, switch means operable to open and selectively close said circuits, operating mechanism comprising a handle for operating said switch means to manually open and selectively close said circuits, said switch means being disposed for operation in the plane operation of said handle, a spring biasing the switch means closed in both closed positions, and electroresponsive means operable 'in response to overload currents in whichever circuit is closed to cause automatic opening movement of said switch means.

13. A circuit breaker for selectively controlling either one of two circuits comprising two sets of separable contacts, a switch member operable in either direction from an open position to selectively close said contacts, operating mechanism comprising an operating handle manually movable for operating said switch member to open and to selectively close said sets of contacts, an actuator releasable to cause automatic opening movement of said switch member from both closed positions, and electroresponsive means normally restraining said releasable actuator and operable in response to overload conditions in the closed circuit to release said releasable actuator and thereby effect movement of the switch member to open position.

14. A circuit breaker for selectively controlling either one of two circuits comprising a pair of spaced stationary contacts, a single switch member operable in either direction from an open position to selectively engage said stationary contacts, operating mechanism comprising an operating handle for operating said switch member, said handle being manually movable to open and to selectively close said circuits, actuating means operable to actuate said switch member to open position, and trip means operable in response to overload currents in whichever circuit is closed to effect operation of said actuating means and thereby eflect movement of the switch member of open position.

15. A circuit breaker for selectively controlling either one of two circuits comprising two sets of separable contacts, switch means operable to selectively close said sets of contacts, operating mechanism for said switch means comprising an operating handle, a spring operatively relating said handle and said switch means, said handle being movable from an on to a central oilf position to manually open said sets of contacts and being operable to move said switch means to selectively close said sets of contacts, means other than said handle releasable to effect automatic opening of said contacts, and means operable by said handle to release said releasable means to thereby effect manual opening of said contacts.

16. A circuit breaker for selectively controlling either one of two circuits comprising a pair of spaced stationary contacts, switch means movable in either direction from an open position to selectively close said circuits, operating mechanism for said switch means comprising an operating handle, an overcenter spring operable by said handle to move the switch means to the open position and also into engagement with one or the other of said stationary contacts with a snap action, means releasable to actuate said overcenter spring to eiiect movement of said switch means in either direction to said open position, and electro-responsive means operable in response to overload currents in either one of said circuits to release said releasable means to thereby effect movement of the switch means in either direction to said open position.

17. A circuit breaker for selectively controlling either one of two circuits comprising a pair oi spaced stationary contacts, switch means operable in either direction from a neutral open position to selectively engage said stationary contacts, operating mechanism for said switch means comprising an operating handle manually movable between on and "03 positions for operating said switch means to open and to selectively close said circuits, a releasable member other than said handle operable to actuate said switch means to open position, and a trip device comprising a thermal element normally restraining said releasable member, and operable in response to overload currents in whichever circuit is closed to release said releasable member and thereby eil'ect movement of said switch means to said open position.

' 18. A circuit breaker for selectively controlling either one of two circuits comprising spaced stationary contacts, a switch member movable to go engage said stationary contacts to selectively close said circuits, operating mechanism for said switch member including an operating handle for manually moving said switch member to an open position and in either direction from said open position to selectively close ,said circuits, a pivoted member between said switch member and said handle operable to cause movement of said switch member from either of said closed positions to the open position, and means nor- 0 mally restraining said pivoted member against operation, said means being operable in response to overload currents to eifect operation of said member.

19. A circuit breaker for selectivel controlling either one of two circuits comprising spaced stationary contacts, a single switch arm having a central open position, operating mechanism including a manual handle manually movable from on to ofi positions to move said switch to said open position and for operating said switch arm to selectively engage said stationary contacts, releasable actuating means operable to eflect movement of said switch arm to said open position, and electroresponsive means normally restraining said actuating means operable in response to predetermined overload currents in I whichever circuit is closed to release said actuating means.

20. A circuit breaker for selectively controlling either one of two circuits comprising a pair of spaced stationary contacts, switch means having a central open position, operating mechanism including a manual handle and an overcenter spring operated thereby for operating said switch 65 means from said open position to selectively engage said switch means with said stationary contacts, a member biased to cause movement of said switch means to said central open position to efiect separation of the closed contacts, a tripdevice normally restraining said member in operative position and operable in response to predetermined overload currents in whichever circuit is closed to effect automatic release of said biased member, and means operable by said manual handle for operating said trip device to effect release of said biased member to thereby efiect manual opening movement of the switch means.

21. A circuit breaker for selectively controlling 7 either one of two circuits comprising two sets of contacts, switch means movable in either direction from an open position to selectively close said sets of contacts, a spring biasing said contacts closed in both closed positions, operating mechanism comprising a linkage, an operating handle for manually operating said linkage to move said switch means to open and to selectively close said sets of contacts, actuating means releasable to actuate said linkage to open position, and a trip device operable in response to overload currents to release said actuating means and thereby effect automatic operation of said linkage and movement of said switch means to open position.

22. A circuit breaker for selectively controlling either one of two circuits comprising two sets of separable contacts, switch means operable in either direction from an open position to selectively close said sets of contacts, spring means biasing said contacts closed in both closed positions, operating mechanism including a handle for manually operating said switch means to open and to selectively close said sets of contacts, actuating means operable to effect automatic opening of said contacts, a second spring for operating said actuating means, and electroresponsive means operable in response to overload currents in whichever circuit is closed to' cause operation of said actuating means and automatic opening of the corresponding set of contacts. l

23. A circuit breaker for selectively controlling either one or two circuits comprising two sets of separable contacts, switch means operable in either direction from an open position to selectively close said sets or contacts, operating mechanism comprising an operating handle for manually operating said switch means to open and to selectively close said sets of contacts, releasable actuating means operable when released to cause automatic opening of said contacts, and a single thermally responsive element normally restraining said releasable actuating means and operable in response to overload currents in whichever circuit is closed to release said releasable actuating means.

24. A circuit breaker for selectively controlling either one of two circuits com-prising two sets of separable contacts, switch means operable in either direction from an open osition to selectively close said sets of contacts, operating mechanism including an operating handle and an operating spring operated thereby for manually operating said switch means to open and to selectively close said sets of contacts, said operating spring providing contact pressure in both closed positions, releasable actuating means operable when released to cause movement of said switch means to said open position to eiTect automatic opening of said sets of contacts, and a single electrores-ponsive means operable in response to overload currents in either of said circuits to ef- I fec-t operation of said actuating means.

25. A circuit breaker for selectively controlling either one of two circuits comprising two sets of separable contacts, switch means movable from a central open position in either direction to selectively close said sets of contacts, operating mechanism including an operating spring, a handle for operating said spring to manually move said switch'means to open and to selectively close said sets of contacts, actuating means biased to cause automatic movement of said switch member to the open position, latch means normally restraining said actuating means against operation, and an electroresponsive element operable in response to overload currents in whichever circuit is closed to operate said latch means and effect operation of said actuating means, said handle being operable when it is operated to close either set of contacts and to reset said actuating means to latched position.

26. A circuit breaker for selectively controllin either one of two circuits comprising two sets of separable contacts, operating means including a handle and an operating spring operated thereby to open and to selectively close said sets of contacts, said operating spring providing contact pressure for both sets of contacts, a releasable actuating means operable when released to cause automatic opening of said sets of contacts, and electroresponsive means normally restraining said actuating means and operable in response to overload currents in either one of said circuits to release said releasable actuating means and cause automatic opening of said sets of contacts, said handle being operable upon operation thereof to close said sets of contacts and to reset said releasable actuating means.

27. A circuit breaker for selectively controllin either one of two circuits comprising two sets of separable contacts, operating means comprising a handle and an overcenter spring operable there-. by to selectively close and to open said sets of contacts with a snap action, said overcenter spring biasing said sets of contacts closed in both closed positions, and electro-responsive means operable in response to overload currents to cause automatic opening of at least one of said sets of contacts.

28. A circuit breaker for selectively controlling either one of two circuits comprising two sets of separable contact-s, operating means comprising a handle and an overcenter spring operable to selectively close said sets of contacts with a snap action, said overcenter spring providing contact pressure for both sets of contacts. a releasable member operable when released to cause automatic opening of said sets of contacts, a second spring for operating said releasable member, and electroresponsive means operable in response to overload currents in whichever circuit is closed to release said releasable member.

29. A circuit breaker for selectively controllin either one of two circuits comprising spaced stationary contacts, a switch member having a central open position and movable to selectively engage said contacts, a releasable member supporting said switch member, a spring operable by said releasable member to cause automatic movement of said switch member to open position, a handle having an open position for operating said spring to selectively move said switch member into engagement with either one of said stationary contacts, and electroresponsive means normally restraining said releasable member and operable in response to predetermined overload currents in whichever circuit is closed to release said releasable member.

30. A circuit breaker for selectively controlling either one of two circuit-s comprising spaced stationary contacts, a switch arm having a central open position, operating mechanism including a handle manually movable to an off position and to an "on" position for operating said switch arm to said open position and to selectively engage said stationary contacts, a releasable trip member operable to eifect movement of said switch arm from either closed position to said open position, spring means biasing said trip member to tripped position, and means operable in response to overload currents in whichever circuit is closed to release said trip member.

separable contacts, operating means comprising a handle operable to selectively close said contacts, said handle being manually movable from an on position to an off position to open said sets of contacts, a single trip member releasable to cause automatic opening of either of said sets of contacts, a spring biasing said trip member to tripped position, and electrores-ponsive means normally restraining said trip member and operable in response to overload currents in whichever circuit is closed to release said trip member,

said handle when moved to selectively close said contacts resetting said trip member.

32. A circuit breaker for selectively controlling either one of two circuits comprising two sets of separable contacts, a single switch member operable to close saidsets of contacts, operating means comprising a handle operable to move said switchmember to selectively close said sets of contacts, said handle being movable from an on" to an off position to manually open said sets of contacts, a spring biasing said switch member 14 closed in each closed position and operable by said handle to operate said switch member, and electroresponsive means operable in response to predetermined overload currents to cause automatic opening of said sets of contacts.

ERNEST G. WISE.

REFERENCES crr'En The following references are of record in the file of this patent:

UNITED STATES PATENTS Mitchell Oct. 30, 1945

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