US2312168A - Circuit breaker - Google Patents

Description

CIRCUIT BREAKER Filed July 25, 1941 2 Sheets-Sheet l 3'11 12 John Gui? i332 Feb. 23, 1943' J. G. JACKSON CIRCUIT BREAKER Filed July 25, 1941 2 Sheets-Sheet 2 INVENTOR (/0717? 6: Jackson ATTO. NEY

Patented Feb. 23, 1943 CIRCUIT BREAKER John G. Jackson, Detroit, Mich assignor to Square B Company, Detroit, Mich, a corporation of Michigan Application July 25, 1941, Serial No. 403,936

'7 Claims.

This invention relates to automatic electric circuit breakers and more particularly to the current responsive tripping means for eilectlng the automatic opening of such circuit breakers upon and 8 within an arcing chamber. an operating handle is provided at H pivotally mounted upon a shaft 12 and having a cam surface eooperat-= ing with the fiat surface or" the member to effect current overload. manual movement or the contact has "i. A com One object of the present invention is to propression spring i i is disposed between the botvide a simple and economical but effective comtom of the base i and the bar l to bias the bined thermal and magnetic tripping means for same. an automatic electric circuit breaker. The lower end of the base is rovided with an Another object of this invention is to provide end lacing terminal comprising a conducting tripping means for an automatic electric circuit connector i5 inserted in slots in the opposite side breaker including a yoke and a movable armawalls of the base from the front and maintained ture member with an intermediate member caragainst endwise removal by both a terminal rying a latching surface moved by the armature screw i6 and an adjusting stud ll. A midwee to eilect tripping of the circuit breaker. 15 tion of the connector is pressed outwardly at it Another object of the invention is to provide a to take up any slack or play the connector combined thermal magnetic tripping means for a mounting. A tab 5!; is pressed out of the con circuit breaker according to the preceding object nector and the stud l'l is threaded into the in which a bimetallic member is provided for also i9 to provide for adjustment of the free end oi 'eflecting movement of the intermediate member a bimetallic member welded on the end of carrying the latching surface. connector, thus providing for adjustment of Other objects and features of the invention calibration oi the breaker the hi will be readily apparent to those skilled in the metallic element 2! is a magnetic yoke 22 which art from the specification and appended drawings is 01' generally U-shape provided with side pins illustrating certain preferred embodiments in 25 23 received within slots on opposite side walls of which: the base to mount the yoke. A magnetic arma- Figure l is a vertical sectional view 0! a-iorm oi ture element 24 is provided having a central slot circuit breaker including the current responsive 25 through which the contact bar passes in its tripping means of the present invention. automatic tripping and resetting movements. Figure 2 is a detail plan view of the tripping An intermediate non-magnetic element 25 is promeans according to the present invention shown vicled between the sides of the yoke. This elewith the circuit breaker cover removed. ment has return bent tabs at its front end at 21' Figure 3 is a detail sectional view on the line and the loops thus formed bear against the inside III-III 0! Figure 1. surface of an insulatmg fiber plate 28 which, Figure 4 is a detail sectional'view on the line with the metal plate 29, is sealably attached to IV-IV of Figure 1. the breaker to form a cover therefor. The mem- Figure 5 is a partial vertical sectional view ber 26 rotates about the engagement of the loop showing a slightly modified form of the tripping 2'1 with the inner surface of the sheet it. means. The armature 21 has recessed rounded portions The present invention has been illustrated in 40 ll received within the loops 2'! which form bearconnection with a circuit breaker mechanism lugs for the rotation of the armature, The upper which comprises a base I having a conducting end of the armature is provided with projecting strap I mounted on one end ledge thereof and tongues 32 received within notches in the oppocarrying at its interior end a stationary contact site side walls of the base which serve to limit the 3, the connector 2 extending through an opening movement of the assemblage. Mounted upon in a fiber plate 4 which closes the end of the. the non-magnetic intermediate member 25 is a base. Exterior oi the plate 4 is a terminal conresilient spring strip 83 welded to the intermedinector 5 for attachment of circuit wiring. Guided ate member adjacent a midpoint and formed to for rectilinear movement within the base is a provide alatching tip at H biased by its resiliency generally U-shaped element 6 upon whose long so away from the plane of the intermediate memleg is pivotally mounted, by inter-engaging bar, but whose position is limited by the engagenotches, a contact bar 1 carrying at one end a ment with the intermediate member of the flange movable contact i cooperating with the station- 35 formed at the end of the leg 36. The oppoary contact 3. Fiber plates indicated at 9 comsite end of the spring strip 33 is formed as shown bine with the plate 4 to enclose the contacts 3 to engage both the surface oi the fiber sheet 28 aid the armature a; isstatemt with as; iiber sheet 28 is indicated'at 11 and the enga e-1.

aerator mal flexing of the bimetali, the two exert a sumcient to eflect eventual release or the contact menttvith the armature is indicatedat 98. By

its engagement with the iibersheet the resiliency oi the spring strip biases the intermediate mem born in a counterclockwise direction as viewed in Figure 1. Similarly, the engagement of the resilient spring stripwith the armature is at the point 33 biases the armature as well in a counterclockwise direction. The limiting position of the armature is determined by a stationary stop on thebas and the limiting position of the intermediate member 24 and hence the position oi the latching tip 34 is determined by adjustment of.

the bimetal 2 l, the bimetal 2! being provided with the reduced tongue 39 received within a slot 4|" in a right angle leg 42 provided at the free end of the intermediate member 26. 1

The circuit breaker mechanism, as shown lni full lines in Figure 1-, is in its normally operating closed circuit position. The dotted lines October 19, 1937.

The operation of the tripping mechanism is asiollows:

For low current overloads of continued duration, the bimetal 2i becomes heated by the passage of current therethrough and flexes in a clockwise direction to move the intermediate member and, accordingly, the latching tip 34, to disengage the contact bar 1 which then rotates in a clockwise direction into the dotted line position under the bias of the spring l0. Upon theoccurrence of heavier overloads, magmechanism in a shorter elapsed time than would be taken by the bimetal alone. When the flux induced in the magnetic circuit formed by the armature 2d and yoke 22 becomes suflicient, the armature is rotated in a clockwise direction and strikes the latching tip 35, moving it downwardly to release the bar '8 as before. The movement oi the latching tip 3i may be efiected independ- 26, or these two members may move together as a unit, depending upon whether the bias of the spring strip 83 or the resistance of the intermediate member to movement is the greater. As a practical matter, the actual tripping movement of the latching tip is probably a combine.- tion of these movements. It is seen that with this arrangement the moving armature 24 strikes the latching tip 36 a her blow to overcome the initial static friction opposing movement thereof.

While the operation of the tripping means for the breaker has been described in terms of ther none elements of the tripping means operate quicker" than normal thermal flexing of the bimetal 29 to effect the tripping of the breaker 'ently of movement of the intermediate member bar.

1 In the modified form of the invention illusstrip 83 is elongated sumciently for the flange 85 to di rectly engage the lower, surface or the bimetal ii i.

trated in Figure 5, the les .38 onthe TZF.

In this arrangement the leg 62 on the intermediate member 48 is omitt'ed'as is the tongue 89, on the bimetal. In this arrangementthe {as netic operation is the same as previously d e' f scribed for the preferred embodiment, but in the thermal tripping the iorceererted by the bimetal' 2! is passed directly to the latching tip 34 through the leg l6 instead of operating on the intermea diate member 28. Again, whether the la tip 'is moved without moving the intermediate, member 28 or the two are moved bodily together will depend upon the value of the bias of the" spring 33 and the resistance which the inte' diate member offers to rotation, the actual operation being immaterial which is produced.

While this inventionhas been described in con nectlon with a particular circuit breaker mocha? nism to show a complete operative structure, it is understood that the tripping means according; to the present invention is not limited to any pare ticular mechanism but may be utilized in many, other distinct mechanism forms to which it is adaptable and, while certain preferred embodi ments' of the invention have been specifically dis closed, it is understood that the invention is not limited thereto, as many variations-will be roadie lyapparent to those skilled in the art andv the prising a magnetic yolre, means energizing said yoke in responseto the flow of current through. the breaker, an armature member movable to ward said yoke to efiect the release of said re leasable means upon the passage of overload current, a non-magnetic intermediate membercarrying a latching surface engaging said re; leasable means and positionedin the path of said movable armature so as to be moved thereby.

into a position where the releasable means. is released,

and said armature having rounded portions Ire ceived within the inner portions of the loop and rotating therein for. pivotal movement. 1

2. In an automatic electric circuit breaker an ing separable contacts and means releasable to eflect separation oi aaldcontacts, current 1 m..

sive means for effecting the release of said re? leasable means upon the passage of an overload. current through the circuit breaker comprising a" bimetallic member heated in response to the flow-. 0! current through the breaker, a magnetic yolre." means energizing. said yoke in response to the flow oi current through the breaker, an a 701i. ture member adapted to be attractedto said so) upon passage of an overload current, an aux-s iliary member carrying a latching surface en=" to the releasing reflect the terms of the toiletries.

circuit breaker" having separable contactsand means releasable to eflect separation of said contacts, current re sponsive meansior eflecting the release of said" releasable meansupou the passage of an over load current through. the circuitbreaker com said intermediate member having looped portions at one end with the outside oi. the loop bearing against a fixed part to provide a bearing for rotation of the auxiliary member dense to the M mm; on

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