US2828388A

US2828388A - Circuit breakers

Info

Publication number: US2828388A
Application number: US544465A
Authority: US
Inventors: Paul M Christensen; Wiktor Dominik; Bryan John
Original assignee: Federal Pacific Electric Co
Current assignee: Federal Pacific Electric Co
Priority date: 1955-11-02
Filing date: 1955-11-02
Publication date: 1958-03-25
Anticipated expiration: 1975-03-25
Also published as: FR1162744A

Description

K 7 0/2 iwi Y 1NVENTOR5 ATTORN March 25, 1958 P. M. CHRISTENSEN HAL CIRCUIT BREAKERS Filed NOV. 2, 1955 United States Patent i CIRCUIT BREAKERS Paul M. Christensen, West Orange, and Dominik Wiktor andJohn Bryan, Newark,--N. J assig'nors to Federal Pacific Electric Company, acorporation ofDelaware Application November 2', 1955,Serial No. 544,465

19 Claims. (Cl'.-200--1-16) The. present; invention relates to circuitbreakersand in particular to small molded-case breakers of the type employedv in lighting: distribution panelboards and in domestic circuit protection in lieu of fuses. I

An. objectofthe invention is to provide-a small circuit breaker of novel construction having quick-break characteristics whenmanually operated for opening'the contacts, even if the" person operating the handle should arrest. the handle part way toward open position. A further object of the invention is. the provision of such a novel circuit .breaker having quick-break characteristics without resort to anover-center spring.

Small-circuit'breakers have been widely used in which a'moving contact is operated from open circuit toclosed circuit condition; and reversely, in which an over-center spring: is employedior biasingthe movingcontact both in the closed'and in the open direction, depending: on the configuration of the operating mechanism. Overcenter springs havethe important disadvantage of. exerting zero force: at the moment that they pass dead center; At such time, there: is the Zerocontact: pressuref and there is also zero: tendency of thespring to drive :the contacts apart, while this condition theoreticallyiexists at' only aninfinitesimal point in the. opening stroke of the operating handle, as a practical matter friction enters the picture so that an appreciable portion of'the' operating stroke maybe found to give weak and uncertain contact pressure. If the handle" were deliberately operated in a decisive stroke then there would be no'proble'm. How'- ever, there is the possibility that one might deliberately retard the handle, or operate it verygradually; and the specifications of some users concerning circuit breakers require quick closing and quick opening despiteall po'ssibl'e deliberate attempts to control the operation of the handle.

The present invention is concerned with a type of circuitbreaker in which a spring is arranged to bias the contactsv away from each other at all times, even when the contacts are'closed, in contrast to over-center spring mechanisms; When the breaker is closed, a locking mechanism holds the contacts closed", against this spring bias. When" the locking mechanism has been released manually, the spring is fully effective at the very start of the opening stroke't'o drive the contacts apart. Such a circuit breaker is improved, according to the present invention, to avoid all possibility of hindering the opening by mis-operation of the handle.

A further'object ofthe invention is to provide a novel small circuit breaker. with quick-make andquick-break characteristics when operated manually without: resort to over-center springm'echanisms for operating the movable contact. It is understood thatthe circuit breaker should also have quick-break characteristics when automatically tripped by an overload. v

The foregoingobjects are. achieved in thenovel illustrative circuit breaker. described below in detail, in which certain additional features of novelty and advantages 2,828,388 Patented Mar. 25, 1958 ice willibe apparent. Inthe detailed description, reference is made to the accompanying drawings, wherein:

Fig. 1 is a lateral view of a circuit breaker embodying the invention withportionsof the enclosure being broken away to reveal the internal mechanism;

Fig. 2 is a similaryiew with the handle in a shifted positioncompared to Fig Land with certain parts shown in dotted lines torepresenta stillfurther operating position.

Fig. 3 is airagrnentary cross-section of a portion of the novel circuit breaker along-the line 33 in Fig. 1-.

Fig 4 is a fragmentary cross-section of the novel circuitbrea'ker alongtheline l -40f Fig. 3.

Fig.7 5 is arr-enlarged fragmentary cross-section of a portion of: the novel apparatus along the line 5-5 in Fig.1.

Fig 6 is aperspectiveof the handle of the circuit breaker in. Figs. 1, 2- andS and Fig. 7 is a perspective of the element in Fig. 1- that cooperates with the'h'andleshown in Fig. 6.

Referringnow to the drawings; there is shown a pair of housing;v members 10'and 12 of molded insulation which supporb'and enclose the operating mechanismof the novelcircuit breaker. This includes a fixed contact 141- on an external terminal'member 16; movable contact 1 8onr contact carrier 20,. having a coil-spring pivot 22, contact 18 being shown to the left' of pivot 22; an .actuator' 2'4h'aving: a. pivot-26 in contact carrier 20 to the right of; coil-spring. pivot 22; a' current-responsive bimetal=2'8united :at its'lett end to contact carrier 20 and at its right end-being in latching. engagement. with actuator 24;:and a second terminal 30'con'nected by flexible braid 321 to the curre'nt responsive' bimetal 28 near the latchend of this bim'eta'li A. bimetal 24a for compensating for ambient temperature variations is as shownwhich may be regardedas a part of actuator 24. The current path through the circuit-breaker thus far described ex tends from terminal 1 6, through fixed and'm'ovable contacts 1'4 and 18',- through contact carrier 20,. b'im'etal- 28 and flexible braid 32 to terminal 30- which is designed to stab int'oa live" bus receptacle; Bivot" 26 embodies insulation (not shown') to interrupt anyposs'ible current path from bimetal 28 through actuator 24"t'o contact carrier 20. e

The contact carrier is shown in it's closed position with movablecontact l 8 b'ea'ring against fixed conta'c't 1 4. The mechanism for operating contact car-rier20' between its closed and open positions is a'sfollowsz A link 34 which is a U-shaped piece of stiffwir'e ha's the sides of the U disposed perpendicular to the view so as to form two'pivotsi One ofthes'e has a bearing in the upper end of the actuator 24 and the other has a bearing in a member 36(Figs. 1, 2, 5 and 7). Handle 38, pivoted on an integral stub shaft 10a (Fig; 5'), operate's member 36"to close the circuit breaker when shifted to the extreme left in Fig. l, and this handle opens the circuit breaker when it is shifted to the right. The co operation of

members

36 and 38 will be discussed in detail below. In the configuration shown, member 36 and element 34' constitute a pair of toggle members which are slightly over center. The extent of over-centering is limited by engagement of'member 36 against an int'e gral stopj 4(lformed in insulating housing member 121 A similar stop portion is formed in housing portion 10 which is broken away from the view in Fig; 1. The pivotal connection between members 34 and 36 (Fig. 1) is above the center line extending from the pivotal axis of member 36 to the pivot axis of member 34 in the actuator 24; In this condition the toggle is said to be locked. V

Pivot spring 22 which appears in Figs. 1 and 2' and is I! 6 shown somewhat enlarged in her of purposes. In the form of circuit breaker illustrated, all of the elements between the toggle member 36 and the fixed contact 14, including

elements

34, 24 andZfi, are rigidin this illustrative circuit breaker. When

toggle

34, 36 is in the position shown, a degree of resilience is introduced in the mechanism which enables contact 18 to bear against contact 14, despite reasonable variations in the parts dimensions in volume manufacture of such circuit breakers. In this function, spring 22 serves as a pivot and it also functions with upward spring bias to swing contact carrier 20 counterclockwise about pivot 26 to develop contact pressure when the

toggle

36, 34 is locked and pivot 26 is fixed. A compression spring 44 is shown that acts between the contact carrier 20 and member 36, in the direction to open the contacts and to shift member 36 and handle 38 to the off or reset position. The force of spring pivot 22 to bias the contacts closed when the toggle is locked is considerably greater than the reverse action of spring 44. Nonetheless spring 44 biases the contact arm 20 in the opening direction to be instantly effective to open the contacts when the toggle is released.

The

linkage including toggle

34, 36 and actuator 24 is effective to operate the contact carrier 20 into closed configuration only when the lower tip of actuator 24 is arrested by the end of bimetal 28. This bimetal may be described as a current-responsive latch which arrests actuator 24. The handle 38 and

toggle

34, 36 operates through actuator 24 to operate carrier 20 for closing the circuit breaker when the actuator is latched. When current passes through bimetal 28 it heats and curves downward. It passes out of latching engagement with actuator 24 when a critical temperature is exceeded corresponding to the current rating of the circuit breaker.

A rigid soft iron bar 42 is united to contact carrier 20 at the same point where bimetal 28 is anchored. In the event of a very sudden overload current through bimetal 28, the resulting flux developed by that current about the bimetal links bar 42. A downward deflecting force is developed, flexing bimetal 28 toward bar 42 and out of latching engagement with actuator 24.

When current-responsive latch 28 releases actuator 24, either because of thermal effect or magnetic effect, actuator 24 swings clockwise about its pivot 26. Compression spring 44 then operates to drive contact carrier 24) counterclockwise.

Toggle

24, 26 is not effective to prevent such motion, when actuator 24 is released. Compression spring 44 separates the contacts at high velocity when current-responsive latch 28 releases actuator 24. There is no lack of spring pressure to open the contacts following the instant that actuator 24 is released, no dead-center condition such as is involved in over-center spring mechanisms.

Apart from the snap action found in opening the contacts after release due to overload, the present circuit breaker operates with snap action both in opening and in closing the contacts in response to manual operation of handle 38.

Handle 38 is operated from the extreme right position (not shown) to the extreme left position shown in order to close the circuit breaker. When the handle is operated in this fashion toggle member 36 is operated counterclockwise and toggle member 34 applies thrust to actuator 24 in order to actuate contact carrier 20 in the clockwise closing direction. A V shaped member 46 is rockably mounted on contact carrier 20 and, during contact-closing travel of the contact carrier, member 46 is biased by spring 44 so that the left-hand arm of member 46 travels alon a cam surface 48 formed in the insulating housing parts and 12. The upper end of the cam surface 48 has a shoulder which arrests member 46 as well as contact carrier 2:?- at a point prior to engagement of contact 18 against contact 14. Thereafter further operation of handle 38 in the closing direction drives toggle member 34'and actuator 24 without corresponding travel of con- Figs. 3 and 4, serves a numtact 18. During this further travel, spring pivot 22 becomes stressed so as to assume approximately the position in Fig. 3. This stress shifts contact carrier 20 downward and somewhat to the right in Fig. 1, and operation of member 36 counterclockwise also shifts spring 44 against the righthand arm of member 46. The result of both these actions is to shift member 46 out of engagement with the shoulder portion of cam 48. Thereafter pivot spring 22 drives contact 18 against contact 14 with a snap action. At this phase of the

operation toggle

34, 36 has been shifted over-center and is nearly against stop 46. Compression spring 44 is ineffectual to separate the contacts at this stage. Snap-closing of the contacts cannot be avoided even by deliberate, slow operation of the handle 38 in the closing direction. 7

As seen in Figs. 5 and 6, handle 38 is supported on a bearing 19a formed as a projection extending from housing wall 10. Ann. 38a extends out of the

casing

10, 12 as an integral operating lever. Annular bearing portion 38b is of limited axial thickness, the space between

members

12 and 10 being filled by a flange extension 380 of the handle 38. The arcuate extent of flange 38c about bearing 10a is here shown as about 10 less than that between shoulders 36b and 360 of toggle member 36 (Fig.

'7). This difference in arcuate extent of the flange 33c and the space between the shoulders of toggle member 36 enables handle 38 to pivot with limited lost motion without affecting toggle member 36. Handle 38 is held against shifting from the position in Fig. 1 to that in Fig. 2 by a leaf-spring detent 50 received in an appropriate recess in member 12, a similar recess also being formed in housing member 10. Flange 38c and portion 38b close off the opening in

housing

10, 12 required for the operating stroke of handle 38a, preventing access to the mechanism and minimizing the number of crevices into which operation- -hindering dirt might collect. Handle 38 is operated clockwise in the opening direction without affecting member 36, until handle 38 reaches the position represented by the solid lines in Fig. 2. In this phase, flange 38c leaves shoulder 36!) and reaches shoulder 360, a lost-motion operation. Further shifting of handle 38 counterclockwise into the dotted line position causes

toggle

34, 36 to shift overcenter into the dotted line configuration shown in Fig. 2. Manual retention of handle 38 in the dotted line position can no longer restrain contact carrier 20, for thereafter spring 44 drives the contact carrier into open position, with portion 52 of contact carrier 20 against stop 54 formed on the inside of

housing walls

10 and 12. With the handle restrained, toggle member 36 moves clockwise and reversely takes up the space between flange 36c and shoulder 3612. If handle 38 is released in any stage short of full off position, spring 44 completes the reset of the handle, thereby forcing the handle into reset position in condition to close the breaker when desired. During the manual opening stroke actuator 24 remains opposite the end of bimetal 28.

Spring 44 is effective to return actuator 24 from the clockwise position assumed after release of the circuit breaker by current overload and into normal position ready for reclosing, by virtue of a rounded right-hand lower end of bimetal 24a, suitably polished, that slides over the top surface of bimetal 28 during such reset operation of the bimetal.

In the event that handle 38 should be mechanically locked in on position following automatic tripping in response to an overload, member 24 remains in its tripped position (clockwise relative to that illustrated) while the bimetal cools. When the handle is thereafter operated to off position, it takes up the lost motion and then can drive the

linkage

36, 34, 24 into reset configuration, with the tip of the bimetal 24a opposite the end of latch member 23. Spring 44 naturally tends to effect this reset; but incase friction of actuator 24 in moving across the top surface of member 28 should prove too great for this action, positive operationof the handle will effect breaker.

Also, in' case this invention is appliedts a circult" breaker in 'at 'its left end, this specalized condition of frictionally-inhibited reset after automatic trip does not occurf The"fo'regoing disclosure represents the presently preferred embodiment of the invention, as'applied'to a known form of circuit breaker, but'it should not be inferred the invention is limited to this-specific form of circuit Otherforms omitting'bir'netal- 24zz m'ay be desired; resilience maybe introduced using "a rigid pivot in place of spring pivot 22; and snap-closing is not dependcut on the particular form of'mech ani's'm shown. Therefore it'is appropriate that the inventionshould be constru'ed broadly in accordance withits full spirit and-scope.

What is claimed is:

1. A circuit breaker including an insulating enclosure, a'fixed contact mounted therein,a movable contact carrier bearing a movable contact, a current-responsive latch carried by said contact carrier, an actuator pivoted to said contact carrier and engageable with said current-respon'sive latch, said actuator when engaged with said latch being operable thereafter to actuate said contact carrier for closing the contacts, a toggle including a first toggle member pivoted to said actuator and a second togg'lemember pivoted to said'insulating housing and-pivotally connected'tosaid first toggle member, a compression spring having one end acting against said contact carrier and having its opposite end acting against-said second-toggle member and being continuously effective to bias said contact carrier and said second toggle member toward their respective circuit-breaker-openpositions,

and saidtoggle being effective to operate saida'ctuator and thereby to operate said contact carrier to circuitbreaker-closed position against the bias of said spring,

said toggle shifting over center into locking position when the circuitbreaker is closed, a handle for said second toggle member having a portion thereof projecting out'of the enclosure through an aperture therein and being operable to shift said second toggle member overcenter in one direction to close the circuit breaker and said handle being reversely operable to release the toggle, there being a lost motion connection between said handle and said second toggle member whereby the-toggle, when shifted from circuit-breaker-closed configuration and over-center moves out of the locking position and enables the compression spring to drive a contact drivethernovable" contact from "open" to closedposition, said mechanismincluding yielding spring- "means and a detent' i arresting the closin'g"motion* of' -the movable con tact me'rnberduringclosin'g operation of the h'andleysaid yielding spring means producing'snap closing of the contacts'aft'er releas'e of' thedetem; means lockin'g the con- --tac'tsclosed-, spring-means-at all tiines biasing the contacts =toward open position; and a-lost-motion connection between said handle and said contac't-carrier effective to release the" locking means and thereby"enable said biasing spring to open -the contacts despite-possible' arresting of the handle part way toward open position after carrier into circuit-breaker-open position despite possible arresting of said handle during its circuit breaker opening stroke, said spring being effective when the handle is released during an opening stroke to operate said toggle and said handle into extreme open position, in condition for a reclosing operation of the circuit breaker.

2. A'circuit breaker in accordance with claim 1 wherein said handle embodies an arcuate flange concealing said second toggle member in all operative positions of the portion of the handle projecting through said aperture.

'3. A'circuit breaker in accordance with claim 1 wherein said handle and said second toggle member have coaxial pivots, said handle embodying an arcuate flange closing off the aperture in the housing in all positions of the handle, said flange having a concave bearing surface and said second toggle member having a complementary arcuate convex bearing surface with shoulders at the arcuate extremities thereof, the arcuate extremities of said flange coacting with said shoulders for operating the toggle, the arcuate extent of said flange being appreciably less than the arcuate separation between said shoulders and thereby establishing said lost motion connection between said handle and said second toggle member.

4. A circuit breaker including an insulating housing having an aperture therein and containing the operative mechanism thereof, said mechanism including a fixed contact, a movable contact carrier bearing a movable contact, a handle projecting from said aperture and operatively connected to said movable contact carrier to release of said'lockin'g means.

SEA-circuit breaker including an insulating housing having an aperture thereinand containingthe operative mechanism thereof, said nie'chaiiism' including a fixed contact, a movablecontact carrier bearing a'movable contact, a handle rotecting-from said aperture and operatively connected-to said movablecontact carrier to drive the; movable contact from open to closed position, rrieans for locking the contacts closed, spring means at' all times biasing'tlre contacts toward open position,

said spring means alsobei'ng a'r'ranged to drive the handle-in'thecontact-openingdirection upon release of the 'lockingmeans, and a lost motion connection between said handle'an'd-said locking means providing for limited idle operation of-sa'id ha'ndle in'relation to the locking means'followed by'relea'se' of the locking means by the handleup'on further operation thereof inthe releasing direction, and said spring being efiective thereafter to "snap-open the'c'ontactsfree of inhibitingaction by said handle:

6. A circuit breaker having an insulated housing formed with an aperture and containing the operative circuit breaker mechanism; a pivotedhandle having a flange closing said aperture and having a manually engageable portion'projecting externally of=the housingthrough said aperture, a member=pivoted in thehousing coaxially with said handle andhaving arcuately separated shoulders disposedfor coaction with the arcuate ex'tremities of the handle flange, said extremities being separated by a smaller angle than the separation between said shoulders whereby to establish a limited lost-motion connection between said 'handle and said member, afixed contact in said housing,

a movable contact cooperable therewith and movable between open position spaced from said fixed contactand closed position against said contact, a'spring operative at all times to bias said movable contact toward open posidemand to bias said shouldered member toward circuitbreaker-open position, a linkage operated by said member to drive said movable contact toward'circuit-breakerclosed position against said spring bias and including means locking the circuit'breaker closed, said handle being effective to shift said shouldered member to release the locking means and said biasing spring being thereafter effective to open the contacts, said handle being ineffective to' arrest the opening of the contactsafter release of the locking means by virtue'of the lost motionbetweensaid handle and said cooperating member, said biasing spring being, effective upon release of the handle to shift the handle into circuit-breaker-open position.

7. A circuit breaker having an insulating enclosure formed with an aperture, a pivoted handle extending from said aperture and having an arcuate portion closing the said aperture in all operative positions of the handle'and having an operating portion projecting externally of the housing through said aperture, a pivoted member'cooperating with said handle and formed with spaced shoulders, said handle also having spaced portions coacting with said shoulders, the spacing between said handle portions and the spacing between said shoulders being different and forming a lost motion connection, a fixed contact'in said enclosure and a contact carrier bearing a movable contact coacting with said fixed contact, a biasing spring arranged to provide contact opening bias in all said handle and including means for locking said contacts when closed by handle operation, said linkage including a current-responsive latch and an actuator cooperating with said latch, said latch being arranged upon current overload through the circuit breaker to release said linkage and enable said biasing spring to open the contacts, said handle also being effective to release said locking means, thereby to enable said biasing spring to open said contacts, said lost motion connection preventing said handle from interfering even if held in locking-means-releasing position.

8. A circuit breaker including an insulating enclosure having an aperture therein, separable contacts in said enclosure, a handle extending from the interior of the enclosure through said aperture, said handle being operable in reverse directions to open and to close the circuit breaker, a linkage connecting said handle to operate one of said contacts, said linkage including a mem her in the enclosure cooperating with said handle through a lost motion connection therewith, a spring biasing the contact carrier toward open circuit position in all configurations of said linkage and said linkage having locking means holding the contact carrier in closed position despite said biasing spring, said locking means being releasable by said handle, said linkage further including a current-responsive latch and an actuator cooperative with said latch efiective to release said linkage for circuit breaker opening operation in response to overload current, said spring also being effective to opentsaid contacts when said handle is operated toward circuit breaker opening position and after release of said locking means despite possible interruption of handle operation in locking means releasing position.

9. A circuit breaker in accordance with claim 8 wherein said operative linkage includes yielding springimeans interposed between said cooperating member and said movable contact carrier, detent means arresting said contact carrier during closing operation of said handle, said arresting means being arranged to release the contact carrier for snap closing of the contacts under the influence of said yieldable spring means during further contact closing operation of said handle, thereby to cause snap-closing of the contacts as well as snap-opening of the contacts irrespective of gradual operation of the handle in both directions.

10. A circuit breaker including a fixed contact, a movable contact carrier bearing a movable contact and having a supporting pivot, an actuator carried by said contact carrier, a current-responsive latch carried by said contact carrier, said contact carrier and said actuator and said current-responsive latch being held in substantially rigid triangular assembly when said contacts are closed and said actuator being releasable by said latch upon overload, a first toggle member pivoted to said actuator, a

second toggle member having a fixed pivot and further having a pivotal connection to said first toggle member, and a spring continuously acting in compression between said second toggle member and said contact carrier in contact-opening direction and in the direction to drive said second toggle member toward normal open-circuitbreaker position, a handle cooperablewith said second toggle member and having a lost-motion connection thereto for operating said toggle members in one direction over center into contact-closed position and operable in the reverse direction to shift the toggle from contactclosed position and over center, with the lost-motion connection thereafter being'efiective to insure operation of the contact carrier into open position despite the possibility of said handle being arrested. 7

11. A circuit breaker including a first contact, a movable contact carrier bearing a second contact, engageable with the first contact, a current-responsive latch operable .to maintain said contacts closed and to release the. contact carrier-for opening said contacts inrespouse to a current overload, and actuating mechanism for said movable contact carrier including a first toggle member operatively connected to said movable contact carrier, a second toggle member having a first pivot and having a pivotal connection to said first toggle member spaced from said first pivot, said toggle members being movable over center in reverse directions to close and open said contacts, a spring continuously biasing said contact carrier in the circuit-opening direction and continuously biasing said second toggle member toward open-circuit-breaker position, an operating member having a lost-motion connection to said second toggle member and effective to operate the toggle from open contact position over center to closed contact position, said operating member being operable reversely to operate the toggle from closed contact position and over center, said biasing spring being then operative to open the contacts, the lost-motion connection being effective to prevent the contacts from being retarded by arresting the manual operator, said actuating mechanism for the moving contact carrier including a detent for arresting the movable contact carrier with the contacts separated during closing operation of said operating member and a yieldable spring enabling continued operation of the manual operator in the closing direction after the contact carrier is arrested by the detent, whereby release of'the detent will allow said yieldable spring to close the contacts abruptly, to achieve both snap-opening and snap-closing of the contacts by operation of the manual operator, despite gradual operation thereof.

12. A circuit breaker including a fixed contact, a movable contact carrier bearing a movable contact, an operating mechanism including a manual operator effective to move said movable contact carrier from circuitbreaker-open position to circuit-breaker-closed position and including a snap-closing spring, support means for said mechanism, and means cooperating with said support means and effective during a closing stroke of said manual operator to arrest the advance of the movable contact carrier and' thereafter being efiective to release the movable contact carrier for abrupt closing of the contacts by said snap-closing spring, a contact-opening spring operatively connected to said contact carrier so as to bias the contact carrier in the contact-opening direction in all phases of circuit-breaker operation, said operating mechanism including means locking the contact carrier in closed position, and a current-responsive overload release for said locking means, said manual operator having a lost-motion connection to said mechanism and being efiective to release said locking means for opening of the circuit breaker by said opening spring, said lost motion connection preventing the manual operator from retarding opening of the circuit breaker after said locking means has been released.

13. A circuit breaker including art insulating housing having an aperture therein and containing the operating mechanism thereof, said mechanism including a fixed contact, a movable contact carrier bearing a movable contact, a handle projecting from said aperture and operatively connected to said movable contact carrier to drive the movable contact from open to closed position, said mechanism including yi lding spring means and a detent arresting the closing motion of the movable contact memher during closing operation of the handle, said yielding spring means producing snap-closing of the contacts after release of the detent, current responsive means and locking means controlled thereby for holding the contacts closed, and a lost-motion connection between said handle and said locking means providing for limited idle operation of said handle in. relation to said locking means followed by release of the locking means by the handle when the handle is moved in the releasing direction, and said lost-motion connection accommodating reverse relative idle operation of the locking means when the spring drives the contacts open free of all possibility of retarding control by the handle.

14. A circuit breaker including an insulating housing having an aperture therein and containing the operating mechanism thereof, said mechanism including a fixed contact, a movable contact carrier bearing a movable contact, a handle projecting from said aperture and operatively connected to said movable contact carrier to drive the movable contact from open to closed position, current responsive means, locking means controlled by said current responsive means for holding the contacts closed, said mechanism including a lost-motion connection having a first part on the handle driving side and having a second part on the driven side of the connection and a spring acting against said second part of said lost-motion connection and effective to bias said handle in the open direction when the circuit breaker is open, said spring also acting at all times on said movable contact carrier for biasing the contacts in the opening direction.

15. A circuit breaker having an insulating enclosure formed with an aperture, a pivoted handle extending from said aperture and having an arcuate flange closing said aperture in all operative positions of the handle and said handle having an operating portion projecting externally of the housing through said aperture, an operated member pivoted coaxially with said handle and having a convex curved surface mating with a concave curved surface of said arcuate flange, said operated member having shoulders cooperable with the arcuate extremities of said flange and said shoulders being spaced further apart than said shoulders whereby to afford limited arcuate operation of the handle without enforcing corresponding operation of the operated member, and circuit breaker mechanism contained within said enclosure and including a pair of contacts operable by said operated member for closing and opening of the circuit through the circuit breaker.

16. A circuit breaker in accordance with claim wherein said enclosure includes confronting walls one of which provides a bearing for said handle and the other of which provides a bearing for said operated member, said operated member providing a further bearing support for the handle by virtue of the convex arcuate surface of the operated member and the cooperating concave arcuate surface of said flange.

17. A circuit breaker including an insulating housing having an aperture therein and containing the operative mechanism thereof, said mechanism including a first contact, a movable contact carrier bearing a second contact cooperable with said first contact when the circuit breaker is closed, a current responsive device carried by said movable contact carrier, a member pivoted to said contact carrier and movable into latching engagement with said current responsive device, a pivoted handle for operating said mechanism projecting exteriorly of said housing, a toggle for operating said member into latching engagement with said current responsive device and efiective thereafter for driving said contact carrier to close the contacts, said toggle including a first member pivoted coaxially with said handle and a second member interconnecting said first toggle member and said latching member, said handle having a lost-motion connection to said first toggle member, and a spring acting between said contact carrier and said first toggle member and effective to bias the handle in the opening direction and the contact carrier in the opening direction when the circuit breaker is open and effective to maintain contact opening bias on the contact carrier when the circuit breaker is closed, said lost-motion connection enabling limited idle movement of the handle in the contact opening direction followed by operation of the toggle in the contact releasing direction to enable the spring to open the contacts, and to enable the spring to provide drive for said handle via said first toggle member in the open" direction of handle operation.

18. A circuit breaker including an insulating housing having an aperture therein and containing operative mechanism thereof, said mechanism including a fixed contact, a movable contact carrier bearing a movable contact, an actuator and overload release means cooperable with each other and carried by said movable contact carrier, a handle projecting from said aperture and operatively connected to said movable contact carrier via said actuator when the latter is in cooperative relation with the overload release means to drive the movable contact from open to closed position, means for locking the contacts closed, spring means at all times biasing the contacts toward open position, and a lost motion connection between said handle and said movable contact carrier and including means to release the locking means, said lost motion connection providing for limited idle operation of said handle in relation to the locking means followed by release of the locking means by the handle upon further operation thereof in the releasing direction, and said spring being effective thereafter to snap-open the contacts free of inhibited action of said handle.

19. A circuit breaker including an insulating housing having an aperture therein and containing the operative mechanism thereof, said mechanism including a fixed contact, a movable contact carrier bearing a movable contact, an actuator and overload release means cooperable with each other and carried by said movable contact carrier, a handle projecting from said aperture and operatively connected to said movable contact carrier via said actuator to drive the movable contact from open to closed position, said mechanism including yielding spring means and a detent arresting the closing motion of the movable contact member during closing operation of the handle, said yielding spring means producing snap closing of the contacts after release of the detent, means locking the contacts closed, spring means at all times biasing the contacts toward open position, and a lost motion connection between said handle and said contact carrier effective to release the locking means and thereby enable said biasing spring to open the contacts despite possible arresting of the handle part way toward open position after release of said locking means.

References Cited in the file of this patent UNITED STATES PATENTS