US2018904A - Circuit breaker - Google Patents

Description

Filed July 11, 1955 2 Sheets-Sheet 1.

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Oct. 29, 1935. E. H. TAYLOR 9 2,018,904 CIRCUIT BREAKER FiledJuly 11, 19:53- 2 Sheets-She et 2 Patented 29, 1935 UNITED STATES PATENT OFFICE to The Chase -Shawmut Company, Newburyport, Masa, a-corporation of Massachusetts Application July 11, 1933, Serial No. 679,901

'23 Claim.

This invention relates to switches and circuit breakers of the type adapted to control light cir- .cuits and the circuits of relatively small pow- ,ered apparatus such as motors and the like.

One of the objects of the present invention is an improved form of circuit breaker that is operated manually by an actuating handle and is moved rapidly into open and closed positions independently of a corresponding movement of the handle and also is moved into open circuit position independently of movement of the handle by an overload current.

The present switch is particularly adapted for gang mounting in an enclosing box and a further 'object of the invention is an improved construe-- tion that lends itself readily to gang mounting and is of small and compact dimensions and wherein the side of one switch in the gang constitutes the cover for the open side of the adjacent switch.

A yet further object is the provision of a circuit breaker of thetype above set forth having overload tripping means including a thermostatic member that constitutes a component part of the movable switch member and is in circuit between the contact terminals thereof.

Another object of the invention is the provision of an overload-trip circuit breaker having overload responsive tripping means therefor and an over-center spring for manually operating the switch between open and closed positions and wherein the over-center spring also constitutes the means for moving the switch into open circuit condition when it is tripped upon overload.

A further object of the invention is the provision of a circuit breaker having a pivotally mounted bridging member and an actuating member therefor that is pivoted to the bridging member and also is latched thereto against independent pivotal movement by an overload responsive mechanism, combined with means acting on the actuating member to move it and the bridging member between switch open and closed positions. the bridging mechanism being so arranged that when the actuating member is unlatched from the bridging member it operates through its pivotal connection therewith to move the bridging member into switch open position.

Another object of the invention is the provision of an indicating device operated by movements of the aforesaid actuating member to give a visual indication of the electrically tripped condition of the breaker.

A yet further object is generally to improve the construction and operation of circuit breakers.

Fig. 1 is a plan view of a circuit breaker embodying the present invention, the breaker being illustrated in closed position.

Fig. 2 is a view similar to Fig. 1 but with the parts thereof in electrically tripped open circuit position.

Fig. 3 is a view similar to Fig. 1 but with the parts thereof in manually operated open circuit position. I

Fig. 4 is a sectional 4-4 of Fig. 1.

Fig. 5 is an exploded view of the operating mechanism.

Fig. 6 is a sectional detail of the guide tube for detail taken along line 10 the over-center spring guide rod taken along line t-B of Fig. 1.

Fig. 7 is a plan view of the movable bridging member. I

Fig. 8 is a front elevation of a gang of circuit breakers of Fig. 1.

The circuit breaker herein illustrated as embodying the present invention has its operative parts enclosedwithin a chamber or compartment Ill of an enclosing casing I 2, the casing l2 being composed of suitable insulating material having '25 an end wall it which closes one end of the chamber and a peripheral side wall l6 which surrounds the chamber, the other end of the chamber being open. The casing also has a bottom wall l8 which is provided with lugs by which the casing can be attached to a suitable support as the back wall 22 of an enclosing box or housing. The

bottom casing wall l8 also carries stationary contact supports 24 which terminate within the chamber I 0 in contact members 26. The side wall iii of the casing at said contact supports is provided with inturned sections 28 that are disposed between the contact members and the openings through which the contact supports pass and function as barriers or bodies to hinder the discharge of flame when the circuit breaker opens under an abnormally high current. The side' wall of the casing has an arcuate front wall 30 which, adjacent the open side of the chamber III, is

recessed to provide a notch 32 through which the operating handle of the breaker is extended. The breaker mechanism is located within the chamber or compartment lil 'within the open end thereof. When a gang of breakers are mounted together in side by side relation as illustrated in Fig. 8 the back wall ll of one casing, overlies and constitutes a cover for the open chamber of the adjacent casing as illustrated in Fig. 8. 1

The operating handle of the breaker includes an arm 34 which is disposed upon the inner face 66 the Opening in all positions of the operating handle. The casing is provided with stoplugs or abutments l8 and 50 respectively which define re-' spectively the switch open and closed positions 0! the operating handle. The movable bridging member comprises a flat plate 52 that can be composed of either insulating material or metal and as here shown as being composed of metal. Said plate has a hub 54 fixed therein which is journalled upon the spacing sleeve 36 of the rivet Ill. Said plate carries a resilient contact supports 56 and 58 which as here shown are comprised of flat resilient strips that are disposed on opposite sides of the supporting plate 52 in generally parallel relation with said plate and with each other and are terminated at their free ends in contact members 60 that cooperate with separate ones of the stationary contact members 26. The contact supports 56 and 58 have refiexed portions 62 that are directed in wardly toward said supporting plate 5! and are twisted at right angles to thepiane oi'the contact' supporting portion of the strips and are fixed to the plate 52 by suitable means as rivets i4 and are insulated from said plate 52 by suitable.

' insulating means as the insulating plates 66. The

contact supports are electrically connected by ag thermal latch plate that is traversed by the' cur rent passing through the, switch and is movable betweenswitch open and closed positions with the bridging member, which includes the supportinfgplatell, and is adapted to operate on excessive currents to eiiect the overload opening 1 oi the switch. The thermal latch comprisesa U-shaped plate of thermostatic material, which can consist of two metals having dissimilar .coeflicients of thermal expansion secured together back to back. The thermostatic plate is iormed or provided with generally parallel spaced legs 68 that are connected at their similar ends by thev integral connecting put or member II, the tree ends of the legs being secured upon the ends 52 of the contact supports 56 and I in electrically conducting relation therebetween by the rivets. The contact supports .and the thermal latch5thus.

constitute in eflect an integral current oonduct 1 ing structure and withthe supporting' 'plate B comprises the bridging member of the breaker.

-:The connecting member .100! the thermal latch.

, is provided winieii .ups enqins; detent 12 iii its upper ia'e'e, or iace that'c'onfronts the open '1 end oi'thecompartment jill, the thermal member is adapted to be reflesed or warped down wardiy when suiiieientiy heated by an abnormal 7 5' current traversing it to effect the open circuit .movement'of the bridging member.

" 1 The bridging member is provided with en mu ating member thereior comprising a plate or arm ll which overlies the head 38 of the rivet ll' and 70 is pivotally connected to the supporting plate-51 by a rivet or other means 18 which is connected with the'piate l! at one sided its pivotai support on the-rivet ll. said actuating member 14" is provided with a detent II which normally I w sages the detent ll-oi the thermal latch to: mov- .moved into opmcircuit position. -It benotedjhatin 1 ing the bridging member into closed circuit posi tion and engages a projection III of the subm tting plate 52 that is spaced back 01' said thermal latch detent." for moving the bridging member marine ally into circuit open position. Thus, under the 6 manual operation of the breaker, the bridging member and actuating member are in eiiect .locked togetherv against independent movement. The projection III is spaced from the latch detent 12 by a distance substantially greater than the i0} :thickness oi! the detent 18 so that there is a sub-:-

stantial amount of lost play or movement of the detent If in irom the engagement of the l projection into the engagement of the detent" llj This lost motion is for the purpose of ini5;

suring a positive and rapid action of the bridg ing member between its two positions even though .the operating handle is moved very slowly in a corresponding direction, as willbe apparent her-e inaiter. The end of the actuating-member ad-SO' iacent the-detent" projects beyond said detent "andconstitutes a. stop and is provided with. an I upturned stop member 82 which when the breaker is tripped electrically comes up against an abutment 84 projecting from the end wall ll 01 the 25' casing; When the'breaker is opened and closed manually, .however. said stop member 82 does not engage the abutment H but is positioned slightly out of engagement therewith in the closed circuit position of the breaker as is illustrated in Fig.'1. 80

Said actuating member ll extends in the opposite direction or away from the detent ii and .across the pivot rivet III for the actuating member and has a pivotal connection 85 witha clevis 88. Said clevis is fixed to one end of a guide rod ll that IS i'szi'reelyaxially movable in a guidetube it, see especially Fig. 6, loosely disposed in an aperture -02 of the upturned end 42 01 the operating ll'm' 34 for pivotal movement thereon. An over-center.

compression spring ll encircles said guide Zrod 4o andtube and has its .e'nds bearing against the clevi; l6 and against outstanding flange 96 of said gnidetube thereby exerting a substantial pressure upon said'aetuatlng member II and the handle tending when the switch is closed-"to hold-the a bridgin and handle incorresponding switch closedpositions, and, switch is open. tohoid the parts inswitchopenposition 7 to-move the rapidly iromoneto the position when-the-handlels Ill moved milloiently'toward its tio'n the" breaker is open it--islciosed" b! the: operating; handleim its switchopen position aufltlehtly toward'itnswitch-closed to move over the l thr h the pivot-.llorthe elem" and. the pivot. oi the movable switch memmovement causes the spring-to exert apreasurejonihe actuating member to rotate it about its own pivot Ii andiree the bridsins Ii memberin'a counterclockwise see Fig. 3,, until the ldetent 'll'has passedh omengagement j .with the rig-plate I andinto-engacetnent with the detent Hot thebridgins byea mguiegirinnuriner mm eeniiiieiy a flhespring'continnestoact tnthe same with cream the andtthe. bridging member to causethe brids'lnsmember to moveiinto-circuitc e ms n o me t the operatins n needles in the reverse operation oration takes place and the mementommune a member I is latched to the bridging member so that both, in effect. move as one unit between switch open and closed positions and the actuating member is not free for independent pivotal movement in any manner that effects a switching operation. when. however, an overload current traverses the closed switch and heats the thermal latch suiiiciently to cause it to warp downwardly to detach the'detent 12 from engagement with the detent the actuating member is then free for independent movement about its pivot II. The over-center spring urges the actuating member for rotation in a counterclockwise direction, Fig.

,1, which movement brings the abutment member 82 thereof against the fixed abutment 04 of the casing. The engagement of the abutments prevents further rotation of the actuating member in this manner. The over-center spring, however, still exerts pressure on its end of the actuating member and thereby tends to cause it to rock or fulcrum on the fixed abutment 04. This action causes the actuating member to act as a lever on its pivot 10 and hence causes the bridging member to rotate in a clockwisedirection about its pivot 00 into an open circuit position as illustrated in Fig. 2, the open circuit position being defined by an abutment 90 of the casing which is engaged by the edge of the supporting member 02. Thus the freeing of the actuating. member from its latched connection with the bridging member and its movement against and about the fulcrum 04 shifts the appiicationof force of the overcenter spring from one side to the other of the center of the pivot 00 for the bridging member and hence causes the spring to eflect the opening movement of the bridging member without, however, any physical movement of the spring across the center. The actuating member is reiatched to the bridging member by a. movement of the operating handle into open circuit position in which position the force of the over-center spring rotates the actuating member in a clockwise direction. restoring the detent 10 into position behind the detent I! of the latch member of the bridging member. The mechanism thus arranged is simple in construction and is positive and certain in its operation.

It will be noted that the pressure between the detents l2 and 10 is exerted mainly in the plane of the thermal latch or at right angles to the warping thereof so that there is little opposition to the warping and the thermal member thus can be sensitive to overloads.

Mechanism is provided for giving a visual indication of the electrically tripped condition of the breaker. Said mechanism includes an indicating segment or target I00 which is pivoted on a pin I02 carried by the operating handle and disposed in a slot I04 of one of the arcuate arms 46 of the handle so that its arcuate surface is disposed in a position to be visible when the handle is in -circuit closed position. The segment bears a suitable indicating mark, which can be a color, on a portion I06 of its surface that,

when the breaker is in manually opened or closed condition, is concealed behind a portion of the arcuate arm 40 but is adapted to be exposed when the breaker is tripped electrically. The segment I00 is connected through a tensile spring I08 with the actuating member I4 at a suitable point intermediate its pivotal point and its pivotal connection 00 with the clevis 06 and preferably over v the axis of the pivot 40. When the breaker is 1 manually opened and closed the tensile spring I 00 is always under such tension as to keep the axis of the spring in line with the pivot I02 of the segment and the pivot 40. When, however, the actuating member is tripped and moves into a position to effect the electrically tripped opening I of the breaker the line of pull of the spring I00 is shifted in such direction as to cause the segment I00 to be rotated sumciently to expose the marked portion I00 thereof and thereby to indi-' cate visually that 'the switch has been opened 10 electrically. Thus theshifting of the position of the actuating member when electrically tripped is caused to indicate the tripped condition of the breaker. a

I claim:

1. A circuit breaker comprising cooperating stationary and movable contact members, and actuating mechanism for the movable contact member having a latch connection therewith and an over-center spring urging said movable'contact member in .one direction when latched to said actuating mechanism and in the opposite direction when unlatched therefrom.

2. A circuit breaker comprising cooperating stationary and movable contact members, actuating mechanism for the movable contact member having a breakable connection therewith and an over-center spring urging said movable contact member in one direction when connected to said actuating mechanism and in the opposite direction when disconnected therefrom. and overload responsive means controlling said breakable connection.

3. A circuit breaker comprising cooperating stationary and movable contact members, operating mechanism for said movable contact member comprising an actuating member having a latch connection with said movable contact member, and an over-center spring acting in one position thereof on said actuating member to move 49 said movable contact member in a circuit closing direction and acting through said unlatched actuating member to move said movable contact member'in a circuit opening direction.

4. A circuit breaker comprising a pivotally mounted contact member, an actuating member therefor having a pivotal and also a latch connection with said movable contact member, and an over-center spring acting on said actuating member tomoveit and said movablecontactmemher from a switch open to a switch closed position and from a switch closed position to a switch open position and when said actuating member is unlatched to move said movable switch member from switch closed to switch open position.

5. A circuit breaker comprising a pivoted switch member, an actuating member therefor having a pivotal connection with said switch member, and a latch connection therewith which normally holds said actuating member against operative movement about its pivot, means including an over-center spring acting on said actuating member to move it and said switch member between open and closed positions, and means providing a fulcrum engageable with said unlatched actuating member to change the point of eil'ective application of the force of said spring on said switch member to move it into an open circuit position.

6. A circuit breaker comprising a pivoted switch member, means including an over-center spring to move said switch member between open and switch member from one side to the other otthe pivot thereof for effecting the opening movement of said switch member.

7. A circuit breaker comprising a pivoted switch member, an actuating member having a pivotal and also a latch connection with said movable switch member, an over-center spring acting on said actuating member on the side of the pivot 01 said pivoted switch member opposite its pivotal connection with said actuating member, and a fulcrum against which the unlatched actmting member is pressed by said spring to move said switch member in a circuit controlling direction.

8. A circuit breaker comprising a pivoted switch member, an actuating member having a pivotal and also a latch connection with said movable switch member, an over-center spring acting on said actuating member on the side of the pivot of said pivoted switch member opposite its pivotal connection with said actuating member, and a fulcrum against which the 'unlatched actuating member is pressed by said spring to move said switch member in a circuit controlling direction and means for moving said over-center spring over center. v

9. A circuit breaker comprising a pivoted .switch member, an actuating member therefor having a pivotal connection therewith atone side '01 the ,switch closed and open positions.

pivotal center of said movable switch member and also having a latch connection therewith so arranged that said actuating and switch members are constrained for pivotal movement as a unit about the pivot of said pivotal switch member, an over-center spring acting on said actuating member on the other side of the pivot of said switch member, means for moving said spring over-center to move the switch member between switch open and closed pomtions, and ai'ulcrum I disposed in position to be'engaged by said imlatched actuating member to effect the opencir cult movement of said movable switch member.

'10. A circuit breaker comprising 'a pivoted switch member movable between open and closed positions, a pivoted actuatingmember ior said switch member having a lost motion connection therewith, and an over-center spring act-,

ing on said actuating member tomove it'and said movable switch member between switch open and closed positions and to move said actuating member from one end to the other of its lost motion connection at the time said over-center'spring passes over center. v f

11. A circuit breaker comprising is pivoted switch member having a pair of spaced abutments, 9. pivoted actuating member for said movable switch member having a detent that is posil iioned loosely between said abutments, and an mal latch carried by said plate and constituting over-center spring acting on said actuating member to move it and said switch member between switch open and closed positions, said abutments and detents being so that said vdetent I between it and said actuating member, means' passes from the engagement of one abutment to. that of the other during the movement of said spring over center. v

'12. A circuit breaker comprising a movable switch member including a pivoted supportingplate, contact members carried thereby. a therthe electrical connection betweensaid contact members, an actuating member for said movable switch member having a normally latched engagement with said thermal latch, and an overcenter spring acting on said actuating member for moving said movable switch member when aoiasos latched into switch closed position and when urilatched into switch open position.

13. A circuit breaker comprising a pivoted switch member, an actuating member therefor" having a latch connection with said switch memg ber, means including an over-center spring for moving said actuating and switch members between switch open and closed positions, and thermal means carried by said switch memberior breaking said latch connection and eiifecting the in circuit opening movement of said movable switch member by said over-center spring.

14. A circuit breaker comprising a pivoted switch member including a thermostatic plate fixed to saidswitch member at one end and tree 15 to warp at the other end, contact members carried by said movable switch member and connected electrically in series with said thermostatic plate, an actuating member pivoted to said movable switch member and also having a latch con- 20. nection therewith through said thermostatic plate which normally restrains said actuating member from operative movement about its pivot, and means including an over-center spring for moving said actuating member and switch. member 25 conjointly between switch open and closed positions and said'unlatched switch member independently of said actuating member between switch member opposite the pivot of said actuating member, means for moving said'over-center 0- spring over-center to move said actuating. and switeh members conjointly between open and ,closed circuit-positions, and means providingwa' fulcrum for said unlatched actuating member dis-' posed 'to cause said over-center spring to act is through the pivot of said actuating member with 'saidymovable' switch member to move the latter from closed circuit to open circuit'position.

18. A circuit breaker comprising a movable 1 switch member including a pivoted plate, contact 60 members carried by said plate, a U-shaped thermostatic platehaving its legs fixed to said plate and connected electrically between said contact member, an actuating member overlying said movable switch member and having a pivotal con- 55 nection therewith at one side of the pivot of said switch member and also having a latch connection therewith controlled by said thermostatic plate, an over-center spring acting on saidactuating member on the side. of the pivot of said switch member opposite the pivotal connection movement oi said-'movablejswltch' member;

17. In aclrcuit" breaker: comprising a switch member movable between switch open and closed 9 positions, and-indicating. means movable. from- .'a switchclosed position into a position which indicates the electrically opened condition oi the switch, the combination therewithv oi an' actuating member movableconiointly with n switch 15 member between open and closed positions and movable independently of said movable switch member when said switch member is electrically actuated for circuit opening movement, and means connecting said indicating means and said actuating member operative upon such independent movement of said actuating member to effect movement of said indicating member into its position which indicates the electrically opened ing member for moving it between switch open and closed positions, overload responsive means for eil'ecting the overload opening of the switch, the combination therewith of an arrangement wherein said connection is breakable and said spring is operative when said connection is broken to effect independent movement of said actuating and movable switch members; said indicator being carried by said handle and being responsive to movement of said independent movement 01 said actuating member to be moved thereby into a position indicating the overload responsive movement of said. movable switch member.

19. In a'circuit breaker comprising a pivoted switch member, an actuating member therefor, an operating handle, an over-center spring connecting said handle and said actuating member for moving it and said movable switch member conjointly between open and closed circuit positions, overload responsive means for eiiecting movement of said movable switch member into open circuit position, the combination therewith of a pivotal and also a latch connection between said actuating and switch members, said overload responsive means being arranged to break said latch connection, said spring being thereupon arranged to efl'eet movement of said actuating member about its own pivot, a pivoted open circuit indieating member, a tensile spring connected with said indicating member and also with said actuating member about in line with .the pivot of said pivoted switch member, said actuating member in its independent movement thereof moving away from the pivot 01' said switch member and hence effecting the pivotal movement of said indicating member.

20. A circuit breaker as defined in claim 19 wherein said operating handle and said pivoted switch member are concentrically pivoted and wherein said pivoted indicating member is car-- ried by said handle.

21. A circuit breaker comprising a pivotedswitch member, an actuating arm for said switch member having a pivotal bearing thereon, a lock between said switch member and actuating arm, tripping means for said lock, a fulcrum engaged by said unlocked arm, and an over-center spring act-ing on said arm, the points of engagement of said arm with said spring and fulcrum being so positioned with respect to the location of said pivotal bearing between said arm and switch member that said spring acting through said latched arm urges said movable switch member in one direction and acting through said unlatehed arm urges said movable switch member in the opposite direction.

22. A circuit breaker comprising a pivoted switch member, an actuating arm pivoted to said switch member eccentrically of the pivot thereof, a latch connection between said actuating arm and switch member, a fulcrum for said unlatehed actuating arm, and an over-center spring acting on said actuating arm.

23. An electric switch comprising a movable contact member, an arm movable in opposite directions for moving said contact member between open and closed positions, means providing two xfulerums for said arm, a spring acting in the ELMER H. TAYLOR.

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