US2504793A - Circuit breaker - Google Patents

Description

April 18, 1950 H. G. BAXTER 2,504,793

CIRCUIT BREAKER Filed April 27, 194:5

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Patented Apr. 18, 1950 CIRCUIT BREAKER Harold G. Baxter, Baldwin, N. Y., assignor to Westinghouse Electric Cron-poration,` East Pittsburgh, Pa., a corporation of Pennsylvania Application April 27, 1943, Serial No. 484,682

(Cl. 20G-116.)

15 Claims.

This invention relates to circuit breakers, and more particularly to circuit breakers of the type which may be operated manually and which are operated automatically in response to overload currents.

An object of the invention is the provision of a circuit breaker havingan improved operating mechanism in which the point of operation of the operating member is variable from one position to another,- depending on Whether the operetion is manual or automatic.

1 Anotherobject of the invention is the provision of a circuit breaker embodying an improved operating mechanism wherein an operating member is provided with a plurality of centers of rotation, the member being manually or otherwise operable about one of the centers and being automatically operable about another of the centers.

Another obj ect`l of the invention is the provision of a circuit breaker embodying an improved operating mechanism wherein an operating member is provided which has a pair of centers of rotation, one of the centers being releasably restrained by a trip device, the operating member being manuf ally operable about the restrained center and automatically operable about the other 4center upon release of` the restrained center.

Another object ofthe invention is the provision of a circuit breaker having an-improved operating mechanism wherein an operating member is operable about apair of spaced pivots, one of the pivots being releasably restrained to provide for manual operation of the member and breaker, n

said one pivot being releasable to effect automatic operation of the operating member and breaker.

Another object of the invention is the provision of a circuit breaker having an improved operating mechanism which, when moved to an l intermediate position and then released, will open and automatically reclose the contacts.

Another objectof, the invention is the provision of a circuit breaker with an improved operating mechanism having. an intermediate position from 2 thereof when read in conjunction with the accompanying drawing, in which:

Figure l is a side-elevational view, with the side-cover plate removed, of a circuit breaker embodying the principles of the invention. The breaker mechanism is shown in vfull lines in the closed position and in dotted lines in the manually opened position.

Fig. 2 is a fragmentary-elevational view of the mechanism shown in Fig. l, but showing the breaker mechanism in the tripped-open position.

Fig. 3 is a side-elevational view of a modicatien of the breaker mechanism shown in Fis., 1, the mechanism being shown in full lines in the closed position and in dotted lines in the manually-opened position.

Fig. 4 is a side-elevational view oi the breaker mechanism shown in Fig. 3, but showing the mechanism in the tripped-open position.

Referring to Fig. l of the drawing, the circuitbreaker mechanism is mounted in a casing H of molded-insulating material having a base portion lf3, a side Wall l5, end `walls Il, and a slotted outer wall I9. A cover plate 2l (shown partly broken away), also of molded-insulating material, is secured to the open side of the casing` I i by means of screws' 23 (only one being shown) which pass through holes in the cover plate 2| and matching holes 25 in the casing Il. Terminals 2l and 29 are supported in suitable slots in the casing Il and are held in place by the cover plate 2 I. The terminal 21 extends into the interior of the casing Il and has secured to its inner end a stationary contact 3l with which a movable contact 33 cooperates. The movable contactv 33 is secured to thefree end of a pivoted L-shaped switch memberor contact arm 35. The pivoted end of the contact arm 35 is bifurcated and the two legs are pivotally supported on pins 31 one projecting inwardly from the side wall l5 and the other (not shown) projecting inwardly from the cover plate 2l. An over-center spring 39 has one end anchored to a pin 4I supported in the legs of the switch. member or contact arm 35. The other end of the spring 39 is hooked over a pin 43 mounted on an operating handle 45 movable between an on position and an oit position. The inner end of the operating handle 45 is U-shaped and the two legs carry pins 4T and-49 extending on both sides of their respective legs. The pins 41 and i9 project respectively into arcuate slots Sl and 53 molded in the side wall l5 and into matching slots (not shown) molded in the cover plate 2|.

The overcenter spring 35 biases the switch the switch` member.

wse'fr'om its full-line position (Fig. 3) to its `diitix-zd-line position. Due to the pin and slot 'connection 'M -69 movement of the handle 65 is transmitted to the operating member 13l which, upon counterclockwise'movement of the handle, rotates in the same direction about the pin 49 as a pivot. During 'the counterclockwise rotation of the operating member 153, the spring 39 is moved overcenter to the left of the pivot pin 31 for the switch members'35'and this arm is then moved to open the contacts with a snap action. Continued movement of the handle 65 in opening direction carries the spring 39 to the left of the pivot pin 49 in which position the spring biases the switch member-35', the operating member 13 and, due to the lpin and slotconnection 'ifi- 69,

'the handle `6 5 to their oit-positions.

The contacts are operatedtothe closed position by manual movementv ofthe' handle 65 in a clockwise direction to its on or full line position (Fig. 3). Early in this movement, the spring 39 passes to the rightl of the pivot pin 49 where it biases the operating member 'i3 in closing direction. Later in the clockwise movement of the handle the sprin'g`39 crosses tothe right of the pivot pin 31 andvv closes the contacts with a snap action.

In both embodiments ofthe invention, if the handle'ti is not moved 'to its off position during an opening operation by the handle, that is, ii'

the handle is'moved'to the intermediate position wherein kthe centerline of the spring 39 lies between'the pivot `pins "31 and 49, the contacts will have opened, but: if the handle is released without moving it to the full-open position, the spring 39 will immediately' move the operating member and the handle to the on position. This will automatically'reclose the contacts as the spring moves to the right of the pivot 31 for However, if the handle is movedv to its ofi position, it will, as previously stated, move the spring 39 to theleft of the pivot .pin 49 where the spring will bias lthe handle 45 (Fig.` 1`) 'or the operating member I3 (Fig. 3)

`in their respective off positions and' maintain the switch member in the open position untilthe handle is` manually displaced" in closing direction.

An advantage of' the invention is that the breaker may be controlled from a remote point to open the contacts, and upon deenergization of the control means, the-contacts will be immediately reclosed by the operating spring. In order rto accomplish this 'function it is necessary to actuate the operating mechanism in opening Ydirection only to the intermediate position. Any

suitable remotely-controllablev actuating means Amay be employed'.

Having described several embodiments of the invention in accordance with the patent statues, it is to be understood that various changes and modifications may bemade therein without departing from someof the essential features of the invention;

Iclaim as my invention:

1. Acircuitbreaker compri'singa'switch mem- `'responsive' means :operableto permit said operating-.membertorbezmovedtabouttanother of .said 75 pivots to thereby effect Aan. automatic opening movement of said 'switclrmemben 2. A circuit breaker comprising a switch member mounted on a fixed pivot and movable to an open and to a closedposition, an operating member having a plurality of spaced pivots, said operating member being operable about either of said pivots to effect opening movement of said switch member with a snap action, manuallyoperable means for moving said operating member about one of said pivots, and current responsive means operable when heated a` predetermined amount to permit said operating member to be moved about another of said pivots, said manually-operable means being operable to move said operating member about either pivot to move the switch member to closed position with a snap action.

3. A circuit breaker comprising a switch member movable-to open and closed positions, operating means for said switch member comprising a member having a plurality of pivots, an overcenter spring operable by said member to cause movement of said switch member to open and closed positions, a bimetal element normally supporting one of said pivots to releasably restrain said operating member, said bimetal element being operable when heated apredetermined amount to releasesaid one pivot and permit operation of the operating member about another of said pivots to effect movement oi the switch member to open position, and manually operable means for operating said operating member about vsaid one pivot to eiect opening movement of the switch member.

fi. A circuit breaker comprising a switch'mer-.ioperating mechanism for said switch meinber comprising an operating member movable to an oi position and to an on position, an overcenter spring operatively connecting the switch member and said operating member operable to cause movementof said switch member to an open position and toa closed position with a snap action, a plurality oi spaced pivots for said operating member, means for reieasably restraining one of said pivots, said restraining means `being responsive to predetermined abnormal circuit conditions to release said one pivot and permit the overcenter spring to opcratethe operating member about another of said pivots to effect opening movement of the switch member, and means for operatingsaid operating member about said one pivot to effect opening movement of the switchniember.

5. A circuit breaker comprising a switch niember, operating mechanism for said switch member comprising a member operable about a plurality of pivots to off and on positions, an overcenter spring operatively connecting the switch member and 'the operating member to cause movement of the switch member to cpen and ciosed positions with a snap action, electroresponsive means engaging and supporting one of pivotsto-releasably restrain said opereting member in the on position, said electroresponsive means beingoperabie in' response to Vpredetermined circuit' conditions to releasesaid operating member to permit said overc'enter spring to operate said operating member about another of said pivots to effect automatic opening oi. switch member, and manual means for operating said operating member about said one pivot to operate saidswitch'meniber.

6. A circuit breaker comprising a switch memf ber, operatingmechamsmfor.said switchimember aso-139e comprising an operating member movable to effeet opening and closing movement of said switch member, an overcenter spring operable by said voperating member to move said switch member to open and closed positions with a snap action, a plurality of pivots on said operating member one of said pivots being releasable to effect automatic movement of said operating member in opening direction, a trip device for releasably restraining said releasable pivot, said trip device being responsive to overload currents to release said releasable pivot and permit said overcenter spring to move the operating member about a second of said pivots, and manually operable means operatively connected to said operating member for operating said member about the releasable pivot to effect manual opening of said switch member.

7. A circuit breaker comprising relatively movable contacts, releasable operating mechanism .for causing automatic opening of said contacts,

said operating mechanism including an operat- Aing member having a pair of spaced pivots, means 8. A circuit breaker comprising relatively movable contacts, operating mechanism for causing automatic opening of said contacts, said operating mechanism including a releasable member having a pair of spaced pivots, an overcenter spring operable by said releasable member tocause opening and closing of the contacts with a snap action, means for rotating the releasable member about one of said pivots to open and close the contacts, and a trip device operable in response to predetermined abnormal circuit conditions to release said releasable member and permit said member to rotate about the other pivot to automatically open the contacts.

9. A circuit breaker comprising relatively movable contacts, operating mechanism for said contacts, a releasable member having a pair of spaced pivots and operable to cause automatic opening of the contacts, means comprising an overcenter spring operable by said releasable member to cause opening and closing of said contacts with a snap action, manually operable means operatively associated with said releasable member for operating said member about one of said pivots to open and close said contacts, and current-responsive means operable when heated a predetermined amount to release the releasable member and thereby permit operation of said member about the other` pivot to automatically open the contacts.

10. A circuit breaker comprising relatively movable contacts, operating mechanism for said lcontacts including a releasable operating handle provided with a plurality of pivots, said operating handle being manually operable about one of said pivots to off and on positions, means operable by said handle when said handle is moved to ofi and on positions to cause opening and closing of said contacts, and electroregsponsive means normally engaging said one pivot to restrain said handle in said "on position, said electroresponsive means being operable to release said handle and thereby permit movement of said handle about another of said pivots to effect automatic opening of said contacts.

11. A circuit breaker comprising relatively movable contacts, operating mechanism for said contacts including a releasable member provided with a plurality of pivots, an operating handle operatively related to said releasable member, said handle being operable to move the releasable member about one of said pivots to open and close said contacts with a snap action, means operable by said releasable member to effect opening and closing of said contacts, and a trip device operable to permit movement of said releasable member about another of said pivots to effect automatic opening of the contacts.

12. A circuit breaker comprising relatively movable contacts, operating mechanism for said contacts including a releasable member provided with a plurality of pivots, means operable by said releasable mem-ber to open and close said contacts, manually-operable means having a pin and slot connection with said releasable member, said manual means being operable to move the releasable member about one of said pivots to open and close the contacts, a bimetal element for releasably restraining said one pivot, said bimetal element being operable when heated in response to overload currents to release said one pivot and thereby permit the releasable member to move about another of the pivots to effect automatic opening of the contacts, said manual means being operable to move the releasable member about the other pivot to effect closing of the contacts.

13. A circuit breaker comprising relatively rmovable contacts, operating mechanism including an operating member movable to an intermediate position and to an olf position to elect .opening of said Contacts, a trip device operable in response to abnormal circuit conditions to effect automatic opening of said contacts, and means for operating said operating member from said intermediate position to automatically close the contacts, said operating membel` when moved 'to said off position maintaining said contacts in the open position.

14. A circuit .breaker comprising relatively movable contacts, operating mechanism for said contacts, said operating member being automatically operable about said one pivot from said operating member in said oif position maintaining said contacts in the open position, and

a trip device operable in response to abnormal circuit conditions to effect movement of said operating member about the other of said pivots to vcause automatic opening of said contacts.

l5. A circuit breaker comprising relatively .movable contacts, operating means for said con- 75 a trip device operable' in response to abnormal circuit conditions to permit said over-center spring to operate said operating member about a le of this patent: 10

UNITED STATES PATENTS Number Name Date second pivot to cause automatic opening of said 2,073,103 Hodgkins Man 9, 1937 0ntCtS 2,107,246 Jackson Feb. 1, 193s 5 2 188 949 Jackson Feb 6 1940 H LD G. BAXTER.

ARO 2,212,732 Fisher Apr. 27, 1940 REFERENCES CITED 2,315,633 May Apr. 6, 1943 T f l i d i th, 2,320,357 Platz et al. June 1, 1943 he G1 Owing fe @ences are 0 lecor n e 2,371,733 christofferson Mar. 20, 1945

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