US2055183A - Electric circuit breaker - Google Patents

Description

sept. 22, 1936. T. A. SPER'RY ELEGTRI C CIRCUIT BREAKER Filed March 25, 1933 2 Sheets-Sheet 2 Thea clore f1.5 Pa/m5.

Patentes sept'. 22, 193e iran sTAres ELECTRIC CUIRUT' BRE y i';

Application mmh 25, 1933, Serial No, 662,792

19 Claims.

The invention relates in general to devices :lor automatically and for optionally opening and controlling electric circuits, and has for a primary object to provide a device which will function either as a manually controlled switch or as an automatic circuit breaker under imposition of excessive current conditions. Other objects are to provide circuit breaking means in which the automatic action is entirely independent ci the manually controlling means; to

provide circuit breaking means which are positively and mechanically forced to open circuit position when the device is released by the current under abnormal current conditions; to provide circuit breaking means :for overload and short circuit conditions which` are independent ci and separate from the normal circuit breaking means; to provide means within a circuit breaker to automatically and instantly open the circuit breaking contacts in case of ailure of the normal operating means of said breaker; to provide circuit opening means the soie function of which is to open the current contacts in case of overload or short circuit conditions within the breaker; to provide a circuit'breaker having a dual, independently operated control system; to provide inexpensive means within a. circuit breaker to automatically shield and protect the main current carrying contacts irom arcing and destructive influences during the making and breaking or" the current through said contacts; to provide overload operating means which will automatically open the current contacts before the manual operating handle starts toward its oil' or open circuit position; to provide means whereby the contacts will open with a wider gap when opened automatically than when opened manually; and to provide a circuit breaker ci simple, rugged construction with easy manulecturing facilities and installation means.

With these and otherlobjects in view, the accompanying drawings illustrate a preferred form 0i the device, wherein Figure l is .a side elevation in closed circuit position, the cover being shown in section; Figure 2 is a similar elevation, in manually opened open circuit position, the cover and base being shown in section; Figure 3 is a sectional end elevation on line 3 3 of Fig. l; Figure i is the same View as Fig. l in automatically opened open circuit position; Figure 5 is a plan View on line 5 5 of Fig. i; and Figure 6 is an end elevation on line 6-6 of Fig. i. Figures 7 and i7 are side and end elevations of the breaker housing; Figures 8 and i8 'are side and plan views of the release arm; Figures 9 and i9 are iront (Gli. milla-M6) and side elevations oi the upper toggle link; Figures lo and 2D are two views oi the release arm spring; Figures ll and 2l are iront and side elevations of the trip lever; Figures 12 and i6 are fragmentary assemblies of the indicator means; 5 Figures i3 and 22 are plan and sectional side views of the carbon holder means; and Figures le and l5 are iront and side views oi the thermal element. it is manifest that these views are subject to modiication in :.Form and arrangement l() to cover such alternative forms of construction as logically come within the scope ci the appended claims.

With further reference to these drawings, in which like numerals refer to like parts througlc- 15 out, the numeral i indicates a base oi insulating material, this base carrying a metallic conductor 2 supporting a non-metallic stationary contact 3 and a stationary metallic contact fi. A dual recess or chamber 5 is formed within said base to receive a pair of current conductors and l and a warping, current actuated thermal element il in series therewith, said element being positioned wholly within said recess, and having an insulated trip catch 9 at its central transverse portion, the conductors 2 and l each having means, as by screws il), to attach the breaker in operative connection in the circuit. A breaker housing or frame l2 is mounted on base l above recess ti, an insulation sheet il being positioned 30 therebetween, said housing carrying a bracket it, pivotally mounted as at |13, upon which is secured an arcuately movable contact member l5 consisflng oi' a, spring blade i5 and a contact carrying blade 2i which is preferably periorately embossed, 3- as at le, to receive a shaped carbon contact it, said carbon being maintained therein by the blade GEB' which is iinedly held by the inverted end 2li of the blade 2l, the said carbon registering, when in closed position, with the contact il. 40 A supplementary blade il carries a metallic contact i8 which registers, when in closed position, with the contact d. A releasabie overarm 23, pivotally mounted on housing l2, as at 22, has plural side arms 23 which are integrally secured by a 4 cross member 25 and are inwardly bent at their oppositel ends 2t to carry a pin 2d. The members 23 each carry a toggle actuating strike 2l and a resetting projection 23. A coiled spring ill is plvotally mounted on the housing l2, as at 2i), and 5@ also on the overarm 23, as at 2Q', to pivotally actuate said overarm, a pair oi said springs bey ing preerablyemployed. .A manually operable handle 32 is pivotally mounted, as at 3l, on the housing l2, and carries a plurality oi lateral 55 wings or strikes 33 to operatively engage the projections 2d to reset said overarm 23 after overload operationof said device. A nger knob 353, having lateral wings 35, is secured upon said handle, and an operative helical spring 35 pivotally connects said handle to the cross bar ll of a toggle linkage yoke 39 which' is supported, as by the notch iid, upon a plurality of formed lateral wings tl each provided with pivotal notches Sil. Pivotally connected to said yoke 39, as at 32, are a plurality of link members' i3 which'are pivotally connected, as at lill, to the bracket it, said yoke and said links forming a multiple link toggle inter-connecting said contact member i5, handle 52, and overarm 23. An adjustable bracket d5, carrying a cross shaft (i5, is pivotally mounted in housing i2 as by rivets G5' to permit a limited arcuate adjustment for the'purpose of slightly raising or lowering the position of shaft lo with relation to the catch t on thermal element t, and may be secured in adjusted or calibrated position, as by screw il positioned within an arcuate slot lll in a projecting wing lll" of saidbracket 55,said shaft supporting a trip lever liti, pivotally mounted as at 5S', said lever being provided with an arcuate slot i9 having an angularly positioned oiiset portion 50 to receive and coact with the pin 2d in the overarm 23, said lever being provided with a depending leg 5i terminating in an arcuate sector 52' and a strike 52 to engage the catch 9 when said breaker is in operative position. Pivotally mounted on shaft i6 is an arcuately movable member 53 having an arm 5d toA provided to insure desired engagement ci' saidY stop 55 with said overarm members 26. An insulating cover 6l having suitable Ventilating openings 62, is provided to cover and protect said breaker, and may be secured upon said base in any desired manner. 'I'he knob 3d and the button 57 operatively project through provided openings in said cover. A shoulder i2' is formed on housing l2 to engage with the wing 33 to limit the travel of handle 32, and a exible conductor 65 and screw 65 are employed to connect the contact member l 5 with the conductor 5. An angularly disposed cam face 63 is formed on yoke 39 to coact with strikes or stops 2 to quickly and completely flex the toggle linkage on overload operation of the device.

It will be observed that the present application is more or less closely related to applicants co-pending application, Serial No. 582,716, led Dec. 23, 1931, and should be considered therewith. In the present application with the breaker in closed circuit position the current enters through conductor 2 and passes through contacts t and I8 (or 3 and i6), arms il and 2i, cable 641, conductor 6, thermal element 8, and out through conductor l. In manual operation, a clockwise rotation of the handle 32 carries the spring 36 past the toggle pivots 38 when the tenaccedas npon the housing pivots 3d, and is checked in its closing movement by the stops 2l on overarm 25 Awhich engage said yoke in operative relation to the cam faces 63 thereon. The yoke Sii is extended materially 'oeyond the knee joint 32 thereof and has an integrally formed Ycrossliar ll to which one end of spring 35 is secured. it should be observed that the stops 2l are so positioned that the median axes of the toggle links 3S and i3 are never allowed to come into or assume a rectilinear alignment one with another, but continually remain in a exed or angular relationship with the knee joint tending toward collapsed position, being heldin said position by the angularity of stress of said main spring on the extended cross-bar il of said toggle. The exing ofthe contact blades, E5', il and 2l, tend to ekert` an opening pressure on the toggle knee through the link @3, and as the main spring axis approaches the pivot point at, this pressure is sufficient to further iiex said knee joint and cause the collapse of said toggle before the main spring I passes over said pivot, and causing said spring to be not classed as of the overcenter type. It will be noted, too, that the relative exure of the blades l5' and 2l, as compared to that of blade il, causes the metallic contact itl to separate from contact d before the carbon contacts 3 and l 6 separate, and to re-close in inverse order.

Under automatic operation, due to overload or short circuit conditions within the breaker, the warping element 3 lexes downward and releases the strike 52 of trip lever i8 allowing the lever to swing arcuately to release pin 2d from the offset portion 56 of slot lid, when the overarm 23 is forced arcuately upward under the action of springs 3|). The toggle links 39 and t3 are constantly in partially flexed position, and as overarm 23 swings arcuately under impulsion of springs 38, the strikes 2l, moving arcuately Vwith said overarm, engage and traverse the cam faces 63 and instantly and positively force the toggle linkage into fully collapsed position, whether the handle 32 is held or free, and opening the'contacts with a positive and instant action.

As the overarm 23 moves upward, the transverse portion 26 moves out of engagement with the stop 55 of the member 53, and allows this member to rock forward under action of'spring 58 to carry the indicator button 5l upward through the cover Si, and as the portion 26 returns to' normal reset position it comes in contact with the upper edge of stop 55, as at SS, which prevents a complete reset ofthe overarm until the button 5l is manually depressed, rocking the member 53 backward to allow complete reset of Ysaid overarm to retain said button in said depressed position. The bracket i5 provides definite means for adjustment and calibration of the trip lever, and for securing said lever in said calibrated position, and the embedding of the thermal element in the base securely protects it from accidental or intentional injury or manipulation, and places it where it is largely free from external ambient temperature conditions and iiuctuations. It is also evident that the movement of the cross-bar 25 under overload operation will allow said contacts to open with a. wider gap under overload operation than under manual operation, as readily shown at 25. It is also evident that with the breaker automatically opened, as in Fig. 4, the contact member I5 will be held fixedly, c r locked, in open circuit position by the action of the springs 30 on the arms 23 maintaining the stops 2l in opposition to movement o! the yoke or link 38 so said contacts cannot be forced or sprung to closed or contact position until the release arm 23 is returned `toward its normal or reset position. It should be noted, too, that the pin 24, carried by lever 23, remains constantly within the slot 49 of the trip lever 48 and so controls. the movement and action ci this lever at all times. The oilset portion 50 oi slot 49 is positioned angularly to the slot 49 and to the motion of pin 24,` this angular position serving both to restrain lever 23 in closed circuit position, and to reduce the horizontal component of the pressure of springs 30 to an operative minimum as the strike 52 rests in contact with catchv 9 of the thermal element 8, and also serves as a means whereby pin 24 resets the trip lever and strike in operative position after automatic operation of said circuit breaker device.

The thermal element 8 is 'preferably of U- shape, having a pair of parallel arms 31 the inner edge oi' each oi' which is formed, as by an arc oi' a circle or other desired conformation, to produce a narrowed or restricted cross-section 68 at or near the middle portion of the armsk 31- so that these arms gradually taper each way toward this central portion'from the extremities 69 and from the cross portion 13 oiv said U-shape. A suitable clamp 1li-is secured'u'po'n the cross portion 13 but insulated thereiromf'by theinsulation 1I, and carries the tripcatch 9 to which may be formed the .truss brace 12 to support this catch in set position against any pressure of the strike 52. The element 8 is bimetallic in character, and is mounted, asby the extremities 69, in electric series with the current through the breaker, warping laterally under the heat engendered therein by said current and drawing the catch 9 out of engagement with the strike 52 upon the passage of an excess of current through said element.

Inoperation, it will be observed, the current enters from the desired source through the conductor 2 and the contacts 3 andV 4, and passes through thecontacts I6 and I8, blades I1 and I', .ilexlble cable 64, conductor 6, thermal element 8, and out through the conductor 1. With the breaker in operative position, the pin 24 is restrained within the offset slot 50, with the strike 52 in engagement with the catch 9. A manual movement of handle 34 in clock-wise direction carriesthe central axis o! spring 36 nearly into alignment with the pivotpoint 38, essentially eliminating temporarily the horizontal component of lateral pressure of said spring, when the flexing action of the blades I5', I1 and 2| acting on the dis-aligned link 43 start an opening or collapsing movement of the toggle links, and further movement of spring 36 completes the collapse of said toggle linkage and the opening of the contacts with a snap action. On overload or short-circuit conditions of current, however, with the breaker in operative position, the warping of element 3 releases the catch 9 from strike 52, allowing lever 48 to rotate under pressure of the springs 30 which force the release lever 23 arcuatel'y upward and simultaneously rotate the strikes or stops 21 into sliding action on the beveled cams 63, mechanically forcing the operative rotation of the link 39 upon its pivot 38 to open said contacts with a positive and essentially instantaneous action. The wings 33 of handle 32, engaging the projections 28 of release arm 23, upon manual operation of the knob 34 in 'clockwise rotation, will reposition the member 23 and the lever 48 so the contacts may again be closed manually by a reverse movement of said knob. The device is trip free of the handle and nonholdable against load.

I claim as new:-

1. In a circuit breaker having xed and movable contacts to open and close the circuit through said breaker, a housing carrying a toggle linkage and an arcuately movable release arm, an operative spring for said toggle linkage, a movable stop for said toggle linkage integral with said release arm, an auxiliary spring to move said movable stop to ex said toggle to open said contacts with a wider gap when operated by said auxiliary spring than 'when opened manually under normal current conditions.

2. A circuit breaker having a housing carrying a movable contact member, a releasable lever pivoted within said housing, a trip lever engaging said releasable lever, a spring secured upon said releasable lever constantly stressing said lever to open circuit position, and thermal means for releasably retaining said trip lever in engagement with said releasable lever, said releasable lever carrying a strike ior retaining said movable contact member in non-closable open circuit position after overload operation until said release lever is returned toward re-engagement with said trip lever.

3. An electric switch and circuit breaker having a housing pivotally supporting a 'releasable lever, a spring pivotally engaging said lever and said housing to stress said lever to released position, a trip lever normally retaining said releasable lever in closed circuit position, a movable stop rigid with said releasable lever, a movable contact pivoted within said housing, said stop forcing said contact to open circuit position on actuation of said releasable lever and maintaining said contact in open circuit position against an external force until said releasable lever is returned toward its normal reset position.

4. In a circuit breaker and switch having an operating handle and a movable contact, an operating spring interconnecting said handle and said contact to actuate said contact under normal current conditions, a pivotal release lever carrying an arcuately movable s top, and a differently positioned stressing means to actuate said release lever to independently force said contact to open circuit position on an abnormal condition of current within said breaker.

5. In an electric switch mechanism having a pivoted operating handle, an operative spring carried by said handle, a housing, a toggle linkage pivoted on said housing, said operative spring flexing said toggle upon manual operation of said handle, and means separate from lsaid spring for exlng said toggle upon abnormal conditions of current through said device though said handle and said operative spring be restrained from their operative function.

6. A switch mechanism in which the main operative spring is operatively attached to a manually operable handle, a housing pivotally supporting a toggle linkage, said spring interconnecting said linkage and said handle to open and to close a movable current carrying contact, a release arm mounted on said housing, an independent spring supported on said release arm and on said housing to automatically actuate said linkage and move said contact to open circuit position on abnormal current conditions, and means to return said release arm to normal operative position.

'7. A circuit breaker having stationary and movable contacts, a housing with parallel side walls, inwardly projecting ears rigid with said side walls, a multiple link .toggle pivotally engaging said ears, a releasable lever pivoted upon said side walls, said lever being provided with stops to engage said toggle adjacent its knee joint to prevent the links of said toggle from assuming a rectilinear alignment, an operative spring engaging said toggle to maintain said links in closed contact position, and independently stressed cam actuated means to collapse said toggle and open said contacts with the passage of an abnormal current through said breaker.

8. In an electrical device having a housing carrying a manually operable handle, a toggle linkage pivotally mounted on said housing, an operative spring operatively connecting said handle and said toggle, an overarm pivoted upon said housing and carrying an arcuately movable stop for said toggle, said stop preventing the links forming said toggle from ever assuming a rectilinear alignment, a iiexibly mounted movable contact arm, said arm when in closed circuit position stressing said toggle toward open circuit position and causing said toggle to iiex and move said contact before said operative spring passes over said toggle linkage pivot point upon manual operation of said handle, and independent automatic means for moving said contact under abnormal conditions of current within said device.

9. A thermally controlled circuit breaker having a stationary contact and a exibly supported movable contact, a housing supporting an operating handle and an arcuately movable release member, a toggle linkage 'pivotally supported upon said housing adjacent said handle, an operating spring connecting said handle and said toggle linkage, said spring opening and closing said contacts under operation of said handle, an independent actuating means engaging said release member to stress said member constantly toward open circuit position, a cam operated lever to normally engage and restrain said release member, a. current actuated means releasably restraining said cam operated lever, said release member automatically forcing said movable contact to open circuit position independently oi' said operating spring on release on said cam operated lever by said current actuated means, and means associated with said release member to manually return said member and said cam operated lever to reset position.

10. An automatic circuit breaker having a multiple link toggle one end of one link of which is pivotally mounted on a stationary housing, and one end of the other link of said toggle pivotally aotuates a movable current carrying arm, a formed cam rigid with said ilrst mentioned link, a lever arm plvotally mounted on said housing, a plurality of lateral projections rigid with said lever arm to coact with said cam to restrain said toggle linkage in closed circuit position and to operatively force said toggle linkage and said contact arm into open circuit position when said lever arm is released on overload conditions of current within said breaker.

11. A circuit breaker having a stationary and a movable contact member, a housing having a plurality of pivotal projections rigid thereon, a toggle linkage engaging said prodections and said movable contact member, cam means rigid with one of said toggle links, a lever pivotally mounted on said housing, stop lugs rigid with notarse said lever to engage said toggle link cam means, a manually operable handle secured upon said housing, inwardly projecting wings on said handie to engage corresponding resetting cams on said lever, an operating spring secured upon said handle and to said movable contact member, an auxiliary spring pivotally engaging said housing and said lever to continually stress said lever to open circuit position, and to move said lever to open circuit position independently of said operating spring when said lever is released upon abnormal current conditions, said stop lugs coacting with said toggle link cams simultaneously forcing said toggle and said movable contact to full open circuit position, and means for repositioning said toggle links and said lever.

12. In a circuit breaker having xed and movable contacts, a housing carrying a manually operable handle, a releasable overarm, a current releasable trip lever to normally retain said overarm in set position, means for producing automatic operation of said breaker upon abnormal conditions of current within said breaker, an indicator member to indicate automatic as distinguished from manual operation of said device, and means associated with said indicator member to prevent the full return of said overarm to set position until said indicator member has been returned to non-indicating position.

13. In a circuit breaker having a exible current actuated member, a trip lever releasably restrained by said current actuated member, an overload operative member releasably maintained in set position by said trip lever, an arcuate slot in said trip lever to coact constantly with a pin in said overload member, an angularly positioned odset portion in said slot to reduce the horizontal component of pressure of said trip lever against said current actuated member to an operative minimum, an overload release indicating member coactable with an arcuately movable stop member to prevent the full resetting movement of said overload operative member until said release indicating member has been returned to non-indicating position, and means for independently stressing said overload member constantly toward its current released position.

14. A circuit breaker having i'lxed and movable current carrying contacts, said fixed contact consisting of a metallic contact member and a. nonmetallic contact member, and said movable contacts consisting of essentially similar plural contact members, said metallic members registering together and said non-metallic members registering together when in closed circuit position, said metallic members opening before and closing subsequent to said non-metallic members, said nonmetallic members being supported in operative position by a cone-shaped base underwedging action, manual means and a current actuated means for separating said contacts with a. snap action, indicator means released by said current actuated means to distinguish current actuated operation of said breaker from manual operation thereof, and means connected with said indicator means to prevent complete resetting of said breaker in operative condition until said indicator means has been restored to non-indicating position, essentially as described.

l5. In a circuit breaker having iixed and movable contacts, a housing carrying a xed pivot for a toggle linkage, a toggle link to engage said iixed pivot, an inclined cam face rigid with said link, a release armcarried by said housing, said arm having a rigid stop thereon to engage said cam face, current actuated means to release said release arm upon abnormal conditions of current within said breaker, means stressing said arm toward open circuit position to force said toggle linkage to open. circuit position, said stop engaging said cam face continually during the automatic release operation of said breaker.

16. A current operated control element for an electric circuit breaker comprising a bimetallic member of essentially U-shape through which the current passes from end to end, said member being mounted adjacent the extremities of said U-shape in series with the current through said breaker, the parallel side members of said U- shape member each having its inner edge formed to a curvilinear line which is essentially symmetrical to a transverse axis at right-angles to said parallel side members adjacent the central portion thereof, said side members tapering from either side of said central portion towardv said central portion, and a strike member rigidly and insulatedly clamped upon the mid-portion of said U-shape between said side members, said strike member having an integrally formed projecting element supported adjacent its outer end by an inclined brace connected with said strike member.

17. A current operated release element for an electric circuit breaker consisting of a bimetallic member of essentially U-shape secured adjacent its extremities in series with the current conductors within said breaker, the side member of said U-shape member each tapering in approximate symmetrytoward a transverse axis at rightangles to said side members adjacent their central portion, said side members flexing to a greater degree, under the influence of the thermal action of an electric current through said member, adjacent their central portion than adjacent either extremity of said side member, and more resistant to flexing action adjacent either extremity thereof than adjacent the central portion thereof, and an insulated catch secured upon the transverse mid-portion of said U-shape member. y

18. In a circuit breaker having a movable contact, a primary stressing means actuating said contact under manual operation only of said breaker, a housing carrying a releasable arm, a stop member movable with said releasable arm, a secondary stressing means engaging said housing and said releasable arm. to actuate said stop member upon abnormal current conditions only within said breaker to pitively force said contact to open circuit position independently of action of said primary stressing means.

19. A circuit breaker as described in claim 18 in which the movable contact is opened to a greater degree when operated by overload conditions than when manually opened.

THEODORE A. SPERRY.

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