US3089930A - Circuit breaker - Google Patents

Description

May 14, 1963 A. J. PASTENE ETAL 3,089,930

CIRCUIT BREAKER May 14, 1963 A. J. PASTENE ETAL 3,089,930

CIRCUIT BREAKER Filed Oct. 18, 1960 2 Sheets-Sheet 2 IZ. /TZIPPED TRIP M EQHANISM SPRING BMS United States Patent Otlce Bgddllli Patented May 14, 1963 3,il89,930 ClRCUlT BREAKER Alexander J. Pastene, Milwaukee, and Robert W. Wischer, Delaiield, Wis., assignors to Cutler-Hammer, inc., lyiln waukee, Wis., a corporation ot Delaware Filed Oct. 13, 1923i), Ser. No. 63,4119 lil Claims. (Cl. Zitti-88) This invention relates to circuit breakers and more particularly to `circuit interrupters which are manually operable to close and open a circuit and are automatically operable from the closed position to open the circuit in response to abnormal conditions in the electrical circuit and to improvements therein whereby such automatic operation can be visibly distinguished from such manual operation.

Circuit breakers of the type to which the invention relates are often mounted in abutting relation in rows r columns on a panelboard. These breakers have an operating handle extending to the exterior of the housing whereby they can be manually turned on and off to close and open the electrical circuit controlled thereby. These breakers are of the thermal and magnetic type whereby they respond to a continuous small overload current or to a large overload current to interrupt and thereby protect the associated circuit. The operating handle of such breaker is rotatably mounted in the housing for reciprocal, pivotal movement between an extreme counterclockwise on position and au extreme clockwise oil position. Moreover, whether the breaker is manually turned off or is automatically tripped, the operating handle assumes its extreme clockwise olf position and remains therein until the breaker is reclosed. This is true although the breaker is of the trip-free-of-the-handle type. That is, the breaker is capable of automatically tripping when the operating handle is forcibly held in its on position. When the operating handle is released following automatic tripping thereof, the internal operating mechanism. rotates the handle to its extreme clockwise off position.

While this type of breaker is functionally eiiicient for its intended purpose, it has the disadvantage that an automatically tripped breaker cannot be visibly distinguished from one which has been turned olf manually.

Accordingly, an object of the invention is to provide such circuit breakers with improved means whereby a tripped breaker is readily distinguishable from one which has been turned off manually.

A more specific object of the invention is to provide such circuit breaker with improved means aifording the operating handle an intermediate stable position to indicate the tripped condition thereof.

Another object of the invention is to provide improved means for readily converting a circuit breaker having a two-position operating handle into a circuit breaker having a three-position operating handle.

A related object of the invention is to afford such conversion by minimum modification of the circuit breaker.

Other objects and `advantages of the invention will hereinafter appear.

While the apparatus hereinafter described is effectively adapted to fuliill the objects stated, we do not intend to confine our invention to the particular preferred embodiment thereof disclosed, inasmuch as it is susceptible of various modifications without departing from the scope of the appended claims.

The invention will now be described in detail with reference to the accompanying drawings, wherein:

FIGURE 1 is a fragmentary front elevation view of a circuit breaker in its manually turned oit position;

FIG. y2 is a view similar to FIG. 1 with the breaker in its on position;

FIG. 3 is a view similar to FIG. 1 with the breaker in its tripped position; and

FIG. 4 is a fragmentary rear elevation View of a cover for the breaker of FIGS. 1, 2 and 3.

Referring to FIG. l, there is shown a single pole circuit breaker having a `shallow insulating housing 2, with its open side closable by an insulatng cover 4, the latter being shown in FIG. 4. The cover is rigidly secured to the housing by a plurality of rivets 6 or the like. Housing 2 `and cover 4 are provided at the top portion of the breaker with out-out portions 8 and i0, respectively, in registration forming an elongated rectangular opening for accommodating .an operating handle i2 which eX- tends to the exterior of the breaker. Handle 12 is provided with a rectangular opening 14 therethrough for receiving a handle tie when `a plurality of breakers are .assembled in abutting relation to form ia plural-pole breaker. A contact clip 15 extends exteriorly of the breaker through an opening 18 at the left-hand bottom portion thereof to form one electrical connection thereto as hereinafter described. The breaker is provided with a latch Ztl pivotally supported on operating handle 12 and suspended therefrom. A latch lever 22, of substantially inverted U-shaped configuration is larranged for cooperation with latch 20 to maintain the breaker in its closed o-r on condition. rlhe lower end 22a of the depending left-hand leg -of latch lever 22 is pivotally supported in -a pivotal recess 24 in housing 2. A helical resetting spring 26 is connected between latch lever 22 and a projection 28 integral with housing 2 for biasing the latch lever in the counterclockwise direction. One end hook of spring 26 is arranged to engage projection 28 and the Aother end hook of the spring engages 1an aperture 2217 in the depending left-hand leg of latch lever 22. A movable `Contact nger 30 is pivotally supported 'at the upper end thereof on the lower portion of oper-ating handle 12. The lower end of contact iinger 30 is connected to an aperture 22e in the mid-portion of latch lever 22. through a helical over-center tension spring 32. A stationary contact 34 which is integral with contact clip i6 is removably held in :a slot in housing 2 for cooperation with movable contact finger 30. Flexible electrical conductors 35 connect `Contact finger 3i) through a bimetal member 37 to an external terminal 39. A magnetic pole piece, not shown, is arranged in operative relation to such bi-metal member for `attracting armature 36. Armature 36 is pivoted at its upper end in suitable opposed cavities 38 in housing 2 and cover 4. Armature 36 extends downwardly from its pivot alongside the aforementioned magnetic pole piece and is normally spaced therefrom for `attraction by the latter. A metallic member lil is rigidly secured adjacent the lower' end of armature 36. Member 4i) is bent so that its free end diverges from armature 36 into engagement with the lower end of latch Ztl to maintain engagement between the lower end of latch Ztl .and a .sui-table catch 22d on latch lever 22. While metallic member 40 is preferably a bimetallic member for altering the operation of the breaker to compensate for ambient temperature changes, it will be understood that it may also comprise a single rigid piece of metallic material welded to `armature 36 if compensation is not required. A slide plate 42 is slidably received in suitable opposed grooves 44 in housing 2 and cover t and is biased in the left-hand direction as seen in FIG. 1 by a helical compressi-on spring, represented by the arrow and legend Spring Bias lat the end of slide plate d2, positioned lbetween the slide plate and an abutting wall of the housing. Slide plate 42 is provided at its left-hand end with suitable cut-'out portions for receiving the reduced end portions of the afore- :up mentioned bimetal member 37 land armature 36 in spaced apart relation. For a more detailed illustration and `description of the circuit breaker operating mechanism, including the parts not shown herein, reference may be had to Martin F. Koenig, Alexander J. Pastene and Lloyd D. Williams `co-pending application Serial No. 1,073 filed lian. 7, 1960, now U.S. Patent No. 3,081,386.

Operating handle 12 is provided with a generally rectangular projection which extends exteriorly of the circuit breaker housing through the opening defined by cutout portions 8 and iii for manual operation to turn the breaker on and off. The central portion of handle l2 diverges downwardly into a substantially semi-circular or semivcylindrical portion 32a to afford reciprocal rotation of `the handle in the housing. The axis of rota tion of such semi-cylindrical portion is provided with a pair of journals 12b extending in opposite directions laterally of the operating handle for pivoting the latter in the housing and cover. For this purpose, cover 4, shown in FlG. 4, is provided with a cylindrical cavity d6 .and housing 2 is provided with a similar cavity, not shown, providing journal bearings for the operating handle. he lower portion of handle l2 is bifurcated into `a. pair of like parallel enlarged portions iZc spaced in the direction of the aforementioned axis. These parallel enlarged portions are provided at the right-hand sides thereof with `alined holes 12d for receiving the outwardly bent end portions of the substantially U-shaped latch Ztl and pivotally supporting the latter on the operating handle. The yoke portion of latch 2t? is flattened into la substantially 4rectangular cross-section and the upper surface thereof is formed at a predetermined downward slope toward latch lever 22. and at a small downward angle from `a plane normal to the plaine of the latch. This downward angle is sufcient to `aord an unstable system. Thus, the sloped portion of the latch engages catch 22d on the latch lever when a predetermined force is applied thereto by compensating bimetal member d@ but slips off therefrom to trip the breaker when such for-ce is reduced or removed. lt will be `apparent that latch 2t? may be assembled on the operating handle by biasing the free ends of the spaced legs thereof toward one another, inserting such ends between the spaced portions of the handle and allowing the outwardly bent portions of latch Zti to spring into holes 12d. The lower left-hand portion of spaced portions 12C of the operating handle are provided with alined holes lt for pivotally -supporting movable Contact finger 39. Movable contact finger 30 is provided at its upper end with bifurcated portions having outwardly bent portions `at the free ends thereof which may be squeezed toward one another and allowed to spring into holes lli/Lf in the operating handle to pivotally support the movable contact finger ion the handle. Movable contact linger 3d is provided with a contact tip 3de for cooperation with contact tip 34a of stationary contact 34 `as seen in FIG. 2 and is yalso provided with `an aperture in the lateral portion at its lower end for receiving the lower end hook of overcenter spring 32. Housing 2 is provided with a wall 47 extending into the inner cavity thereof to serve ias `a stop for the right-hand depending leg of latch lever 22 when the circuit breaker is tripped. A projection 43 is provided in housing 2 for guiding latch lever 22.

An 'essential feature of the invention is the provision 'of a coil spring 5t? for affording operating handle l2 an intermediate stable position between its on `and od positions when the circuit breaker is electrically tripped. ICoil spring 50 is mounted on a projection S2 molded integrally with housing 2, the coil portion thereof being freely received on projection 52. One end of coil spring S0 extends tangentially therefrom in a straight line :and is held `against the inner surface of the upper wall of housing 2. The other end of spring Sti lies `against the bottom .surface 4of the cavity in housing Z and has a curved portion overlying the apex of a substantially Laterally spaced portions 12e of operating handle 12 are provided with cut-out portions lig to atord clearance for the ends of coil spring Sti between the operat ing handle and the upper wall of housing 2. It will be apparent that the apex of wall 54 forms a stopt for theI curved end ot coil spring Sil, as shown in FlG. 3, to determine the intermediate position of operating handle 12 when the circuit breaker is tripped. Coil spring S9 is held on projection 52 by a substantially larger projection Sd molded integrally with cover d as shown in FIG. 4 which overlies the coil spring when cover 4 is assembled. Cover 4 is also provided with a lateral projection 58 molded therein for holding the lower left-hand end 22a of latch rever 22 in its pivotal recess 2f; when the cover is assembled.

The operation of the circuit breaker will now be described. Let it be assumed that the breaker is in its stable oli position as shown in FlG. l. ln this position, operating handle l2 is substantially in its extreme clockwise position, being removed therefrom not more than 5. To tarn the breaker on, operating handle l2 is rotated to its extreme countercloclovise stable on position shown in FIG. 2. As a result, latch 2d operates on catch 22d of latch lever ZZ and pivots the latter counterclockwise. Movement of the operating handle also causes movable Contact finger 3d to move downwardly. This separation of latch lever 22 and contact linger 3d cau-.ses over-center tension spring 32 to stretch. When the latch lever and movable contact linger pass through their dead center position, the tensile stress in over-center spring 32 causes movable contact linger .ed to pivot clockwise with a snap action, so that contact tip fida moves into engagement with Contact tip 34a to complete the circuit through the breaker. When the circuit breaker is manually turned oil by the operating handle, the contacts open and the mechanism thereof again assumes the position shown in FlG. l. lt will be apparent from FlG. l that in this position latch 2@ remains in engagement with catch 22d on latch lever 22 and the tension in over-center spring 32 moves the operating handle to its off position shown in FlG. l. it will also be apparent that in the olf position, shown in FIG. l, over-center spring 32 has overpowered coil spring Sti so that the curved end portion of the coil spring has been raised from the apex of wall Se.

Let it be assumed that the circuit breaker is electrically tripped either by the bimetal member 37 under thermal action or by a magnetic pole piece in response to a high overload current, the latter being shown in the previously mentioned copending application. ln either case, slide plate 42 slides in the right-hand direction. Such movement of slide plate 42 removes the bias force from armature 36. As `a result, the force normally applied by compensating bimetal member dii against latch 2t) is decreased and latch 2d* slides olf catch 22d to release latch lever 22. As a result, over-center spring 3?. pivots latch lever 22 clockwise until the end of the right-hand leg thereof stops :against wall 47 as shown in FIG. 3. Latch lever Z2 carries over-center spring 32 through its dead center position relative to contact finger 3% and thereby causes the latter to snap open. The remaining tension in over-center spring 32 acts through movable contact nger 3d to rotate operating handle l2 clockwise to the position shown in FIG. 3 until one of the laterally spaced portions 12C of the operating handle engages the bent end portion of coil spring it. Over-center spring SZ is provided with a relaxed length such that the tension therein is exhausted before the operating handle moves all the way to its extreme clockwise position. Thus, spring 5d stops operating handle 12 in an intermediate position against the force of resetting spring 26 as shown in FIG. 3. The 4intermediate position is at a point between the extreme counter-clockwise and extreme positions of the operating handle which point is predetermined by the construction and shape of the cooperating members.

To reclose the circuit breaker, it is necessary to move operating handle 12 from the intermediate position shown in FIG. 3 to its extreme clockwise position or sutliciently so that latch engages catch 22d on the latch lever, this movement of the operating handle being against the tension in coil spring 50. When engagement between latch 20 and catch 22d has been made, the circuit breaker mechanism assumes the position shown in FIG. 1. It is then necessary to move the operating handle counterclockwise from the position shown in FIG. l to the position shown in FIG. 2 to reclose the contacts..

Let it be assumed that spring 50 is removed from the breaker. Now, when the bias force applied by member 40 on latch 20 is electrically reduced, latch 2@ slips` orf catch 22d to trip latch lever 22 from the position shown in FIG. 2 to the position shown in FIG. 3. Such clockwise rotation of latch lever 22 under the overpowering force of over-center spring 32 causes resetting spring 26 to stretch. Also, the mechanism passes through its dead center position whereupon over-center spring 32 pivots nger 3@ counterclockwise to open contacts. The remaining tension in over-center spring 312 acts through movable contact finger 30 to rotate operating handle 12 from its on position shown in FIG. 2. toward its oli position thereby to lower latch 20 toward catch 22d;

It being assumed that spring 50y has been removed, resetting spring 26 now rotates latch lever 22 counterclockwise. As a result, latch lever 22 acts through overcenter spring 32 and movable cont-act finger 3) to rotate operating 4handle 12 clockwise all the way to its ofi position wherein it is thereafter held. Such rotations of latch lever 22 and operating handle 12 in opposite directions causes further lowering of latch 20 and raising of catch 22d above the yoke portion of the latch to afford reengagement thereof.

From the -foregoing description of operation of the breaker with `and without spring 50, it will be apparent that the breaker can be readily converted from one having a two-position handle to one having a three-position handle by the addition of such spring.

We claim:

1. In a circuit breaker, an operating handle having an on position and an off position, an operating mechanism, a latch in engagement with said operating mechanism, said operating mechanism maintaining said operating handle in its on position when the breaker is closed and maintaining said operating handle in its oil position when the breaker is manually opened, said operating handle in its ofi position indicating the manuallyopened condition of the breaker, a current responsive mechanism operable to afford disengagement of said latch to trip the breaker to its open condition, resetting means for reengaging said latch and for moving said operating handle to its cti position, and means affording said operating handle an intermediate stable position to indicate the tripped condition thereof comprising means operable in response to tripping of the breaker for stopping said operating handle in said intermediate position against the force of said resetting means.

2. The invention deiined in claim l, wherein said stopping means comprises a :spring normally disengaged from said operating handle when the latter is in its on position, said spring being positioned in the path of movement of a portion of said operating handle to stop the latter in said intermediate position when the breaker is tripped.

3. The invention dened in claim 2, together with an insulating housing for the breaker, means molded in said housing for mounting said spring, said spring having a projection extending into the path of movement of a portion of said operating handle, and a stop in said housing cooperating with said projection to alord a predetermined stress in said spring whereby to stop said operating handle against the force of said resetting means, said stress being insutlicient to prevent movement of said operating handle to its oi position under the force of Said operating mechanism when the latch is engaged.

4. In a circuit breaker, an operating handle having an on position and an oft position, an operating mechanism, a releasable latch engaging with said operating mechanism, said operating mechanism maintaining said operating handle in its on position when the breaker is closed and maintaining said operating handle in its o position when the breaker is manually opened, said operating handle in its oit position indicating the manually-opened condition of the breaker, a current responsive mechanism operable to release said latch to trip the breaker to its open condition, means operable following tripping of the breaker for initiating movement of the operating handle to its off position, and means affording said operating handle an intermediate stable position to indicate the tripped condition thereof comprising means eiiective responsive to tripping of the breaker for stopping Said operating handle in said intermediate position against the force of the iirst mentioned means, said stopping means being overpowered by said operating mechanism when the breaker is manually opened with said latch in engagement to move said operating handle to its oit position. I

5. In a circuit breaker, an operating handle having an on position and an oft position, an operating mechanism comprising an overcenter spring and a latch, said latch being in engagement with said operating mechanism to maintain said operating handle in its on position when the breaker is closed and to maintain said operating handle in its off position when the breaker is manually opened under the force of said overcenter spring, said operating handle in its off position indicating the man- -ually-opened condition of the breaker, an overload current responsive mechanism operable to afford disengagement of said latch to trip the breaker to its open condition under the force of said overcenter spring, a resetting spring for acting on said operating mechanism to move said operating handle to its oit position and to reengage said latch, and means providing said operating handle an intermediate position to indicate the tripped condition of the breaker comprising tensioned means responsive to tripping of the breaker counteracting the force of said resetting spring to stop said operating handle in said intermediate position, said overcenter spring being efective when the breaker is manually opened while said latch is in engagement to counteract the force of Said tensioned means to move said operating handle to its off position.

6. In a circuit breaker, in combination, relatively movable contacts, an operating lever having an on position wherein said contacts are closed and an off position wherein said contacts are open, an overcenter mechanism operable by said operating lever to close and open said contacts, a latch engaging said overcenter mechanism when said operating lever is moved to its on and 01T positions and acting on said overcenter mechanism to maintain said contacts closed when said operating lever is in its "on position, said overcenter mechanism being effective when moved through its dead center position by said operating lever to move the latter all the Way to its off position to indicate that the breaker has been manually turned off, a current responsive trip mechanism responsive to an overload current -flowing therethrough for affording disengagement of said latch to trip said overcenter mechanism and to open said contacts, and resilient means operative when said overcenter mechanism is tripped in response to disengagement of said latch for stopping said operating lever in a stable intermediate position to indicate the tripped condition of the breaker.

K7. In a circuit breaker having an operating mechanism, an operating handle for actuating said mechanism to turn the breaker on and oli a latch engaging said operatspaanse ing mechanism when the breaker is turned on and off, said latch acting upon said mechanism to maintain the breaker in its on condition and being disengageable from said operating mechanism to trip the breaker to its on condition, said operating handle having one extreme position in which it is held when the breaker is turned on and having another extreme position in which it is held when the breaker is turned 011, a trip mechanism responsive to overload flow therethrough for affording disengagement of said latch to trip the breaker to its o condition and resetting means responsive to tripping thereof for eitecting reengagernent of said latch therewith and for moving said operating handle to its extreme oli position, the improvement including means adording said operating handle an intermediate stable position and comprising a resilient member overpowered by said operating mechanism whereby the latter moves said operating handle to its eXtreme o'd position when the breaker is manually turned oiij said resilient member being operative to overpower said resetting means to stop'said handle in said intermediate position responsive to tripping of the breaker.

8. In a circuit breaker, in combination, relatively movable contacts, an operating lever having two stable positions, an overcenter mechanism, a latch member normally in engagement with said overcenter mechanism, current responsive trip mechanism normally maintaining said latch member in engagement with said overcenter mechanism and responsive to excessive current flow to atlord disengagement thereof, said overcenter mechanism being responsive to movement of said operating lever between said two positions to close and open said contacts while said latch member remains in engagement with said overcenter mechanism, said overcenter mechanism being tripped upon disengagement of said latch member therefrom to open said contacts and to move said operating lever from one position toward the other position, a resetting spring thereafter operative on said overcenter mechanism to move said operating lever to said other position and to effect reengagement of said latch member and said overcenter mechanism, and means affording said operating lever a third stable position to indicate the tripped condition of said overcenter mechanism compris.- ing means overpowering said resetting spring to render the latter ineiective.

9. ln a circuit breaker, in combination, a stationary contact, a movable contact, an overcenter mechanism, latch means for engaging said overcenter mechanism, an operating lever operable when turned to its on position to actuate said overcenter mechanism to move said movable contact into engagement with said stationary contact and operable when turned to its ott position to actuate said overcenter mechanism to move said movable contact out of engagement with said stationary Contact, a current responsive trip mechanism attording disengagement of said latch means from said overcenter mechanism to trip the latter in response to overload current flow therethrough, disengagement of said latch causingy said overcenter mechanism to move said movable Contact out of engagement with said stationary contact and to move said operating lever toward its off position, and spring means operative to stop said operating lever in an intermediate position following trip-ping of said overcenter mechanism to indicate the tripped condition of the breaker, said spring means being ineffective to stop said operating lever in said intermediate position against the force of said overcenter mechanism when said operating lever is manually turned oi 10. in a circuit breaker having an insulating housing, an operating handle rotatably mounted in the housing for 'eciprocal movement between an on position and an ott position, a stationary Contact `mounted in the housing, a releasable lever pivoted in the housing, a movable contact member pivoted on the operating handle, an overcenter spring connected between the lever and the movable contact member, a latch for engaging the lever to maintain the handle in on position with the contacts closed, a current responsive trip mechanism affording disengagement of the latch from the lever in response to overload current flow therethrough, a resetting spring connected between the lever and the housing normally operable Afollowing tripping of the breaker to move the operating handle to its on position, the breaker mechanism also maintaining the operating handle in its ofi position when the breaker is turned oil by the operating handle, the improvement comprising means providing the operating handle with a stable intermediate position between the on and o1 positions to distinguish the tripped condition of the breaker from `the manually turned ott condition and comprising spring means operable to engage the operating handle and to prevent movement thereof past said intermediate position when the breaker is tripped, said spring means overpowering the force of the resetting spring, said overcenter spring overpowering said spring means to move the operating handle to its off position and to maintain the same therein when the breaker is manually turned ott and the latch remains in engagement with the releasable lever.

References Cited in the le of this patent UNiTED STATES PATENTS 2,332,496 Baxter Oct. 26, 1943 2,357,210 Leonard Aug. 29, 1944 2,660,223 Dorfman .tune 10 1952 2,623,967 Herman Dec. 30, 1952 2,662,948 Christensen Dec. 15, 1953 2,693,516 Drobney Nov. 2, 1954 2,802,080 Locher Aug. 6, 1957

Claims (1)

1. IN A CIRCUIT BREAKER, AN OPERATING HANDLE HAVING AN "ON" POSITION AND AN "OFF" POSITION, AN OPERATING MECHANISM, A LATCH IN ENGAGEMENT WITH SAID OPERATING MECHANISM, SAID OPERATING MECHANISM MAINTAINING SAID OPERATING HANDLE IN ITS "ON" POSITION WHEN THE BREAKER IS CLOSED AND MAINTAINING SAID OPERATING HANDLE IN ITS "OFF" POSITION WHEN THE BREAKER IS MANUALLY OPENED, SAID OPERATING HANDLE IN ITS "OFF" POSITION INDICATING THE MANUALLYOPENED CONDITION OF THE BREAKER, A CURRENT RESPONSIVE MECHANISM OPERABLE TO AFFORD DISENGAGEMENT OF SAID LATCH TO TRIP THE BREAKER TO ITS OPEN CONDITION, RESETTING MEANS FOR REENGAGING SAID LATCH AND FOR MOVING SAID OPERATING HANDLE TO ITS "OFF" POSITION, AND MEANS AFFORDING SAID OPERATING HANDLE AN INTERMEDIATE STABLE POSITION TO INDICATE THE TRIPPED CONDITION THEREOF COMPRISING MEANS OPERABLE IN RESPONSE TO TRIPPING OF THE BREAKER FOR STOPPING SAID OPERATING HANDLE IN SAID INTERMEDIATE POSITION AGAINST THE FORCE OF SAID RESETTING MEANS.

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