US2375881A - Circuit breaker - Google Patents

Description

Patentedv lMuay 15, 1945 UNITED STATES PATENT OFFICE Michigan mpany, Detroit, Mich., a corporation oi' Application February 27, 1942, serial No. 432,562

This invention relates to devices for making and breaking electric circuits and more particularly to automatic circuit breakers.

The object oi the present invention isto provide an automatic electric. circuit breaker having improved means for indicating an automatic trip condition.

Other objects and features of the invention will be readily apparent to those skilled in the art from the following specification and the appended drawing illustrating certain preferred embodiments of the invention in which:

Figure 1 is a front elevational view of an enclosed circuit breaker according to the present invention.

Figure '2 is an enlarged sectional view taken on the line lil-l1 of Figure l.

Figure 3 is a view similar to Figure 2 but with the operating parts shown in automatic tripped position.

Figure 4 is a-sectional view taken on the line IV-I'V of Figure 2.

The circuit breaker according to the present invention embodies a cup-shaped insulating base I having a metallic cover 2 sealably secured thereto as by studs or in any other desired manner and with an insulating sheet 3 disposed back of the cover 2. i

A generally S-shaped conducting connector 4y is disposed at theforward end of the base I and extends through an opening 5 in the bottom`6 of the base to the exterior and islrigidly held in posilton within the base by a stud 1. At its exteriorly 4disposed end, the connector 4 carries a terminal stud 8 for securing a cable lead to the breaker while a stationary contact surface 9 is mounted upon the interior end thereof. A second conducting connector, II is provided at the rear of the base I and comprises two elements I2 and I3 rigidly fastened together by a rivet I4 with the element I2 being secured to the rear wall I5 of the base bya stud I6 and with the element I3 secured to the bottom of the base by a stud I1 to thereby rigidly maintain the connector in place. Element I2 extends through an opening ,I8 in the bottom 6 to the exterior and f carries a terminal stud I9 at its outer end. A bimetallic element 2| is rigidly welded or othern wise secured to the interiorly disposed end of the .w yconnector element I2. A member 22 is disposed within a recess 23 in base I and maintained therein by the dening walls of the recess and by a stud 24 threaded throughthe member. The stud 241s adapted to bear against the connector I2 s claims. (ci. zoo-11s) and serves as an adjusting or calibrating means for the bimetallic element.

A metallic frame or support 25 is provided within the base I spaced from thevbottom 6 of the base and held in position therein by ribbed formations, not shown, on the side walls. A pin 26 is carried by the support 25 and provides a pivot upon which is pivotally mounted a-manual operator 21 comprising a body portion formed of molded insulation and having a handle portion 28 extending through an opening in the cover 2 to the exterior of the switch, also an actuating member 29 and a contact lever or switch' member 3|, the latter having portions thereof disposed on opposite sides of the manual operator 21 and the pivotal or actuating memberf29. A contact surface 32 is provided at the forward end of the switch member 3| and is adapted to cooperate with stationary contact 9 to complete a circuit therethrough. The pivot 26 is located intermediate the ends of the switch member 3| and since the manual operator 21 and the member 29 are mounted on this pivot they are thus disposed intermediate the ends of the switch member. The operator 21 is provided at its underside with a depending portion 33 carrying a pivot 34 on which is mounted a spring guide 35. The switch member 3| carries a cross piece 36 having a slot 31 extending therethrough adapted to receive the free end of the guide member 35. A compresis interposed between shoulder formations on the guide and the cross piece 36 for a purpose to be described. A spring 39 having one end secured tothe lower part of the pivotal member 29 and its opposite end xed to a projection 4| on the support 25.: continually biases the pivotal member for counterclockwise movement. The operator 21 is cu't away as at 42 and is thereby adapted to be manually moved in the normal operation of theswitch without affecting the pivotal member 29. operator 21 is disposed immediately adjacent the pivotal member 29 when the contacts are engaged and is adapted both to movethe pivotal member 2-8 or to be moved thereby under certain conditions to be hereinafter described. In the normal position of the pivotal member A29, the lower tip 43 thereof engages the free extremity of the bimetallic element 2| and is retained in this position against the bias of spring 39. A flexible lead 44 interconnects the bimetallic element 2| and the switch member 3|, being connected to that part of switch member 3| not shown in the cross-section -views of Figures 2 sion spring 38 is disposed about the guide 35-andl The depending portion 33 of the.

and 3, to place the bimetallic element in series circuit with the contact. A generally l. shape insulating nbre member dll is secured to the connector ll by the rivet Ml and is disposed between the exible lead 1M and the bimetallic element 2l to prevent short circuiting therebetween; for a clearer presentation of the device that portion oi the nbre member ib which is disposed to the lett oi cutting line II-l'l of Figure i isshown in dotted outline in Figures 2 and 3. n` ange d@ on the support provides a stop adapted to en-a gage a portion of the switch member til to define the extent of pivotal movement thereoi in a clockwise direction.

Disposed against an interior plane surface oi the connector l and secured in place by stud 'l is a bracket member carrying a pin upon a leg flll thereof. Rotatably mounted upon the pin lll" is a generally l.shaped actuating member comprised of molded Bakelite and carrying a detent pin A spring is coiled about the pin and has one extremity engaging liraclr` et member do and the other extremity bent to engage the i.shaped member to continually bias it and the detent pin lil thereon. for movement in a clockwise direction.

The breaker is provided with a circular opening extending through the cover E, the insulating sheet and into a partial substantially circular recess 5t provided in the base l and with the recess communicating with the interior of the base. im indicating` pin 5d is disposed within the opening lit and is movably retained therein by the detent pin bil', the free extremity oi which extends into a recess bb provided in the indicating pin The indicating pin bil will normally be maintained within the base l through its interconnection with the rotatable member lli, as is illustrated in Figure 23 being movable therefrom upon actuation of the rotatable member it in a cloclswise direction. This movement of the rotatable member moves the detent pin bl, which moving effects rectilinear movement of the indicating lpin lill to carry a substantial part thereof beyond the cover 2. Ledge 5U provided by the bracket do is engageable by the detent pin 5l to thereby dene the amount of clockwise movementJ of this pin and thus determine the extent ci movement of the indicating pin 54 beyond the cover 2. The rotatable member 49 normally occupies the position illustrated in Figure 2, being carried to and maintained in this position against the bias of the spring52 by the member 29 and being movable therefrom only' upon the occurrence of an overload as will be hereinafter described.

The operation of the switch will now Vbe described.

From the on position of Figure 2, the initial movement of the operating handle 21 counterclockwise to off position eiects a compression oi spring 38 to direct a force upon the switch arm 3l below its effective center of rotation, maintaining the contact engaged until the line of force of the spring 38 is carried through theplvot 26 whereupon the energy in the compression spring 38 becomes active to move the switch member 3l with a snap action in clockwise direcftion to disengage the contacts, the switch member 3| moving until it engages the limiting stop 40. To effect re-engagernent of contacts, the manual operator 21 is moved in the reverse direction and a reverse action of the parts occurs.

In the'automatic operation of the parts, the occurrence of an overload current heatsV the aardbei member itl moves countercloclrwise under the bias of spring The pivotal member in this movement engages depending portion til of the manual operator il ior positive movement thereof to carry the line oi force of spring lili through the pivot to move the, switch member ti to Contact disengaged position with a snap action. Release of the actuating member @t by the birnetallic element causes it to move out oi en gagement with the rotatable member where upon this member is free to rotate upon its axis under the bias ci spring to move the detent pin lil which moves the indicating pin lili to carry a substantial. portion thereof beyond the cover E to thereby intricate the .tact that au overload has occurred in the breaker. The indicar ing pin may be vividly colored to more readily direct an observers attention to the existence oi' an abnormality within the breaker.

To reset the breaucr, the manual operator il is moved clockwise. The depending portion in its resetting movement engaging and moving pivotal. member to a point slightly beyond the free end of the bimetallic element il where itsl c ure 2. Movement of rotatable member (59 moves detent pin lil thereon countercloclrwise to carry the indicating pin baci; into the breaker. This resetting movement of the manual operator also eects a snap movement ci the switch member 3l into contacts engaged position, for the line of force of spring will be carried through the pvot the snap movement ci the switch member occurring substantially simultaneously with the movement of the pivotal member 229 beyond the free end oi the bimetal 2l. With release of the manual operator ill the tip lll moves toward re-engagement with bimetal lll under the bias of spring .ttl and ii the condition oi over load still exists, the parts will promptly disengage for the heat created by the flow of overload current will move the free end of the bimetallic member 2l out of latchingr position and the parts will move again to off position and the detent pin 5l will rotate clockwise to again move the .indicating pin 54 to carry the upper portion thereof beyond the cover 2 thereby signifying that an overload condition still exists.

It is seen, however, that the construction herein described-permits the contacts to be held en gaged, even though a condition of overload exists, by holding the manual operator in the on position, to provide for a situation where the operator iinds it necessary to maintain a circuit despite the existence of an overload current.

' It is to be noted that ifthe manual operator is held in the on position, the pivotal member 2S will continue to restrain the rotatable member 49; thus the indicating member 54 cannot move out of the breaker to disclose the presence of an overload current. The fact that the indicating member 54 is hidden informs the operator that a circuit is being maintained.

While certain preferred embodiments of the invention have been specically disclosed, it is understood that the invention is not limited -thereto as many variationsv will rent to those skilled in the art and the invention.

said indicating be readily appais to be given its broadest possible interpretation within the terms of the following claims:

What is claimed is:

l. In a non-trip free manually and automatically operated electric circuit breaker, stationary and movable contacts, switching means for effecting movement of said movable' contact into and out of circuit making position, a manual operator movable to move said switching means, means responsive to an overload current for actuating said switching means to circuit breaking position, overload condition indicating means movable from an inactive position to an indicating position on the occurrence of an overload current, said indicating means comprising a movable member mounted separately from said manual operator and normally adapted to move independently thereof on the occurrence of an overload current, and means under the control of said manual operator for, maintaining said indicatingmeans in said first position even on the occurrence of an overload current when said manual operator is restrained in contacts on position.

2. In an automatic electric circuit breaker, a.

stationary contact. a movable contact, a switching arm for effecting movement of said movable contact into and out of engagement with said stationary contact, a manual operator, means for eiecting snap movement of said switching arm in response to movement of said manual operator, a bimetallic element, a spring biased actuating member for moving said switching arm, said actuating member being independent of said snap means andbeing normally held by said bimetallic element in an inoperative position, and being releasable by said bimetallic element on the occurrence of an overload current to positively move said manual operator to "oif position to effect snap movement of said switching arm to contacts disengaged position. an overload indicatingmeans adapted to be maintained in inoperative position during manual operation of the switching arm to contacts on and oiT position, and

means operable on the occurrence of an overload current to move said indicating means to a position indicating the overload condition.

' 3. In an automatic electric circuit breaker, separable contacts, a switching arm for effecting separation of said contacts, a manual operator, means for effecting snap movement of said switching arm in response to movement of said manual operator, a bimetallic element, a spring biased pivotal actuating member for moving said switching arm, said actuating member beingnormally held by said bimetallic element in inoperative position, and being releasable by said blmetallic element on the. occurrence of a predeterv mined overload current to move to leffect snap movement of said switching arm to contacts separated position, an overload indicatlngmeans, a pivotal 'member operatively'associated with said indicating means and mounted independently of and separate from said actuating member and engaged by said actuating member to maintain means in anon-indicating position during manual operation of said switching arm, said v pivotal member being released for movement when said actuating member moves on the occurrence of a predetermined current overload, to move said tion indicating current actuation of the breaker as distinguished from manual actuation, said manual operator being actuable after automatic indicating means to a, posi-- 4. In an automatic electric circuit breaker, a

stationary contact, a switching arm, a contact carried by said switching arm for cooperation with said stationarycontact to make and break an electric circuit therethrough, a manual operator, means for` eiecting snap movement of said switching arm in response to movement of said manual operator, a bimetallic element, a spring biased actuating member for moving said switching arm, said actuating member being normally held by said bimetallic element in an inoperative position and being releasable by said bimetallic element on the occurrence o1' a predetermined overload current topositively move said manual operator to oir position to effect snap movement `of said switching arm to break the electric circuit through the breaker, an overload indicating member, said indicating member being maintained in non-indicating position during manual operation of said switching arm but being adapted to move to a position indicating automatic operation of the device when a predetermined current overload occurs .in the circuit, resetting means including said manual operator, said manual operator being actuable to on position after automatic operation of the breaker to simultaneously return both said actuating member and said indicating means to their initial position.

5. In an automatic electric circuit breaker, stationary and movable contacts, afswitching arm movable to move said movable contact, for engagement. and disengagement with said stationary Contact, a manual operator, snap acting means associated with said switching arm and actuable by said manual operator to eifect snap movement of said yswitching arm, an actuating switching arm and adapted dicating means in a non-indicating position during manual operation of the switching arm, said movable member moving on the occurrence oi a c urrent overload to eilect movement of said indicating means to a position indicating automatic, as distinguished from manual, operation of the breaker, said manual operator after autocating means toits initial position.

6. In. an automatic `electric circuit breaker, a stationary contact, a movable contact, a switchieieesebiy engaging@ tutti actuating member to tioioi it Meinst tbe bien of said spring mesi n Seidl ectuating men'ibein being released by Seial reieufse indicating membei'9 n spring: biased 101V-- 'otsii membetotesutiveiy esseciuteoi with se-,ici in-il 1 me in mounten uitlenendentiy ot nstuntinib ncinbei und engageant@ by seid ectueting irfiembei, ,fisici pivotni inc-:minetd ummeliyf upon indicating membei" to inemtein in et nou-=y Mexiting misition during;

tor, efbimeinilicelement, said bimeteiiie elementuei operation of the switching erm, said pivotal member being released by said actuating member on the occurrence of en. current overload for movement under its spring bias to effect movement oi said indicating means to a, position in (inentingr current actuated operation of the breaker as distinguished from manuel operation thereof, sc ioi manual operator after automatic opereton of the breeker being operable toward on position to engage with and positively move seid actuating member into e. position where it is reeneagedi by seid bimeteiiic member, said eictuating member in this movement being engagenbie with said pivotal member foi' positive move ment thereof to tetuin seid indicating means to its initiui position.

GEEF J. EELJER.

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