US2468852A - Circuit interrupter - Google Patents

Description

J. M. WALLACE ETAL May 3, 1949.

CIRCUIT INTERRUPTER Original Filed June 24, 1941r -ea H: 171

Patented May 3, 1949 CIRCUIT INTERRUPTER J ames M. Wallace, Braddock, Herbert L. Rawlins, Swissvale, and James M. Cumming and Wayne S. Aspey, Turtle Creek, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania riginal application .lune 24, i941, Serial No.

399,452., Divided and this application November 1, 1944, Serial No. 561,384

.4 Claims. l

This invention relates to electric circuit intere rupters in general, and more particularly to operatingmeans for such interrupters.

This invention is a division o the subject mat oi' our copending application on Circuit interrupters, Serial No, 399,452, l'iled June 24, 194i,

assigned to the same assignee of this invention.

The specic disclosure hereinafter given oi this invention is embodied in an automatic reclosing circuit breaker having separable contacts and ctromagnetic means for separating the concts, and with the contacts and contact-actuing mechanism all suspended in a container :nom the container cover.

@ne object of this invention is to provide novel means for readily removably supporting the electromagnetic operating coil.

Another object of this invention is to provide a novel assemblage of the operating mechanism for an automatic reclosing circuit breaker of the type described which will permit changing of the rating of the breaker in a relatively simple manner.

Still another object of this invention is to provide a novel unitary assembly with the cover of a circuit breaker casing, of the breaker contacts, and contact-actuating mechanism.

These and other objects of this invention will become more apparent upon consideration of the following detailed description of a preferred embodiment thereof, when taken in connection with the attached drawing, in which:

Figure 1 is a substantially central vertical section through a circuit breaker embodying this invention with certain parts thereof shown in elevation;

Fig. 2 is a partial elevational View of the operating mechanism shown in Fig. l;

Fig. 3 is a transverse sectional view of the breaker shown in Fig, 1 taken substantially on the line III-III thereof with certain parts omitted;

Fig. 4 is a fragmentary sectional view of the lockout integrating mechanism employed in the breaker shown in Fig. 1;

Fig. 5 is a view like Fig. 4 but showing the parts of the mechanism in a. diierent position from that shown in Fig. 4; and

Fig. 6 is also a partial sectional view illustrating the mechanism of Figs. 4 and 5 in a still diierent position of the parts thereof.

The circuit breaker constituting this invention is shown by way of example as being mounted in a tubular insulating casing 2 which may be of any desired insulating material, preferably porcelain or the like. The casing 2 is provided with .a closed bottom and an open top, with the top being closed by a cover assembly fl, and the bottom of the casing havin-g associated therewith a terminal assembly 6. Intermediate the ends of the casing 2 there is provided a cylindrical surface 8, and a supporting bracket l2 is adapted to be clamped around this cylindrical surface with resilient material Ill interposed between the clamp l2 and the outer casing wall to prevent damage thereto.

The terminal assembly 6 at the bottom of the casing includes a terminal bolt I4 of conducting material adapted to extend through a substantially central aperture in the bottom casing wall, and the bolt is provided with an enlarged head i@ interiorly of the casing, with packing material 2li interposed between the head I8 and the bottom wall of the casing. A nut 22 and washer 24 co-operate with bolt I4 to retain the same in position, and a conductor 28 may be secured to 'the bolt, for example, as by a second nut 2S. Bolt I4 is preferably provided Wtih a substantially central bore 30 for the purpose of draining casing 2, the lower end thereofbeing adapted to be closed by a screw threaded closure plug 32.

The upper end of casing 2 is ribbed, and a supporting flanged ring 34 is adapted to be secured to this ribbed portion of,4 the casing, for example, as by cast metal, or the like, 36. Supporting ring 34 is adapted to have cover assembly 4 secured thereto in any desired manner, not shown.

The casing and terminal structure 6 described above are substantially identical with those more particularly described and claimed in the copending aplication of J M. Wallace and H. L. Rawlins,

Serial No, 374,686, tiled January 16, 1941, and in their Patent No. 2,318,421, issued May 4, 1943, both of which are assigned to the same assignee as this application.

Cover assembly 4 comprises an integral casting having a flange 38 formed integrally with the lower end thereof and, adapted to seat on the upper end wall of casing 2 and extend over the interior of the casing. Flange 38 is also provided with integral outwardly extending ears (not shown) adapted to be bolted to ears formed on supporting ring 34. The cover assembly casting is provided with a hollow portion including the top wall 4I), side walls 42, 43, and end walls 44 and k45, with the bottom of the hollow portion being open and located over the open top of casing 2. At one upper corner of the hollow portion of cover assembly 4, an inclined wall is provided with a threaded aperture for co-operation with a threaded filler plug 4B, by means of which casing 2 may be filled with an arc extinguishing iluid. Top wall 4U of the hollow portion of the cover assembly is extended beyond the hollow portion and slightly inclined downwardly as at 48 to form the top wall of a sleet hood portion having side walls 52 and 53. The top wall 48 of the hood portion terminates in an angularly downwardly extending lip 50, for a purpose to be hereinafter described.

As appears from Figs. 1 and 3 of the drawing, ange 38 of the cover assembly 4 has portions which extend over the open top of casing 2, and these portions are adapted to insulatingly support the circuit breaker contacts and operating mechanisrn, for example, as by the tubular insulating spacer sleeves 54. The spacer sleeves 54 have the opposite ends thereof threaded for co-operation with screws 56 and 58, to secure the spacers to ange 38 and the upper leg |06 of a U-shaped supporting frame $0, respectively. -The other leg i113 of U-shaped frame 60 is secured to one end of a generally rectangular frame 64, and the other end ci this frame is preferably formed integral with the top cap 66 of an interrupter interrupter chamber 6E includes an inng tube 'l0 or" fiber or the like, having one eaded into top cap 66, and having the i end threadedly received in a bottom ter-s l rop cap 86 is provided with a. subally central aperture 89 for closely slidably a with spaced outlet apertures la adapted controlled by a sliding valve plate |ll2, ncrced by a coil compression spring |04 inte nt with the adjacent end of insulating The lower end cap 14 ci the interrupter rr is provided with inlet passages l, and

.ibstantially centrally located threaded for receiving the threaded end or' an `just-cle fixed contact 18 which is secured in ositicn, for example, as by a lock nut 80. The i end of end cap 14 is reduced in size to form shoulder d?. on which is seated one end of a impression spring 84, with the other end of spring hearing against the head i8 of ternal bolt il. Spring 84 should be of some good resilient conducting material, such, for example, as a cooper alloy or the like.

The lower end of Contact piston rod 12 is pro- 'ed with a socket for receiving the upper end of act rod 86, secured in the socket, for example, a rivet 83. The lower end of contact rod is enlarged to form a contact head 90. A liquid directing piston 92 is provided with a central aperture 9| so that the piston may be slidably mounted on Contact rod 86 for movement between contact head 90 and the lower end of Contact piston rod 12. The lower end of contact piston rod 12 is counterbored to receive a coil compression spring 93 which normally operates to bias liquid directing piston 92 towards contact head EE. As shown, piston 92 is provided centrally with hollow portion to which access is obtained by means of a plurality of top apertures 94, and single lower aperture 95 concentric with contact head 9|! so as to form an annular liquid passage therewith. Liquid director piston 92 may have a peripheral slot for the reception of piston ring d6 to prevent leakage of liquid between the piston and inner wall of tube 1U. A stop ring 98 is secured in position between the lower end of insulating a contact rod 12, and the cap is also tube 1l and lower end cap 14 and. as shown, projects inwardly so as to form a stop for liquid director piston 92, :o that when the contacts are closed, the piston is maintained in a position intermediate the limits of its movement on contact rod Il. The inlet apertures 'Il in cap 14 are adapted to be controlled by a check valve plate Ill freely mounted between the end wall of end cap 14 and stop ring 9|. 'I'he lnterrupter chamber Il described above is substantially identical with that described and claimed in the above-mentioned copending application of J. M. Wallace and H. L. Rawlins, Serial No. 374,686, except that in the interrupter chamber herein described, valve plate |02 is spring biased in one direction, rather than being frictionally associated with contact piston rod 12 as in the said copending application.

The operation of the interrupter chamber herein disclosed and illustrated is substantially the same as that in the above-identified copending application and comprises, brieily, utilization of fluid pressures generated by a-n arc drawn, to obtain contact separation. by the instant structure, because it will beobserved that as soon as contact piston rod 12 is moved upwardly and contact head 90 moves out of engagement with iixed Contact 18 to strike an arc, the action of such an arc on the same extinguishing liquid within the chamber, such, for example, as oil or the like, will decompose the same to generate a gas which will build up a pressure within chamber 68. As soon as this pressure builds up, it will obviously force check valve plate IM and valve plate iii! outwardly relative to insulating tube 10 to close both the inlet and outlet apertures 16 and 13, respectively. Gutward movement of valve plate |02 readily occurs because the upper side of this plate is vented by aperture |03. Accordingly, such pressures within the chamber will act on contact piston rod 12 in a piston-like manner to force the same to move outwardly of the chamber, and thereby increase the contact separation. In the upward movement of contact rod 85, liquid director piston 82 remains stationary until contact head engages the upper wall of the director tc thereby draw the arc out to an optimum length before moving the director to cause a how of liquid through apertures 94 and 95 and into the arc to extinguish the same. Contact piston rod 12 and contact rod t6 will be moved outwardlg,T by the pressure developed within arc chamber 88 until the combined action of attentuation of the arc and ilow of liquid therethrough cause extinction. As soon as the arc is extinguished, the contact piston rod 12 is adapted to be moved downwardly towards fixed contact 18 in a manner to be hereinafter further described, and since pressure is no longer being generated within. the chamber, spring H34 will be free to'move valve plate |02 downwardly to open outlet passages 13 and permit exhaust oi' gases and used liquid out of the upper end o! the arc chamber. This upilow of gas and used liquid from the chamber will be taken care of by an inflow of fresh liquid through inlet apertures 16, which will cause check valve plate |00 to be unseated due to the pressure at the bottom of the casing because of the head of liquid therein, and especially because of the difference in pressure due to the difference in the head of liquid between inlet apertures 16 and outlet apertures 13. Consequently, it can be seen that the fluid pressure developed by the are is utilized in this interrupter to obtain contact This ls accomplished separation, and that during a closing operation of the breaker contacts, the used arc extinguishing fluid within the chamber is replaced by fresh fluid from casing 2,

As previously stated, the substantially U- shaped supporting frame member 60 is secured to the upper end of rectangular supporting frame 64, and the frame member 60 is for the purpose of supporting a solenoid coil H2. The upper and lower legs |06 and |08 of supporting member 60 are connected by spaced integral legs ||0 positioned at one side thereof, so that the solenoid coil ||2 may be assembled with support 60 by merely slipping the entire coil between legs |06 and |08 through the open side of support 60. The legs |06 and |08 of the U-shaped frame 60 are provided with aligned apertures adapted to coincide with the central bore provided in solenoid coil ||2, and a securing sleeve or core guide tube II4, of insulating material, is adapted to be inserted through the aperture in leg |08 of the U-shaped support 60 into engagement with a shouldered plug IIB seated against a shoulder provided about the aperture through leg |06 of U-shaped supporting frame 60. Securing sleeve |4 is maintained against movement downwardly from the supporting frame 60, as viewed in Fig. 1, by the connection of rectangular frame 64 thereto, inasmuch as the end plate |I8 of this frame is provided with a shouldered aperture, with the adjacent. end of securing sleeve I I4 seated on the shoulder of this aperture to prevent movement thereof with respect to U-shaped frame 60. Frame 60 is of magnetic material to form a stationary frame for coil ||2 as well as a support therefor. Rectangular frame 64 is secured to the lower leg |08 of U-shaped frame 60, for example, as by screws 62, or the like. It will be noted that solenoid coil I2 is provided with a plurality of taps ||9 which are connected to different sections of the coil, and located away from the connepting legs ||0 of the U-shaped support 60, at the open side thereof so as to be readily accessible for the purpose of changing the coil connections when desired. Rectangular supporting frame 64 is provided with the side plates |20 integral with top plate I8 at one end thereof, and with top cap 66 for the interrupter chamber at the other end thereof.

The upper end of contact piston rod 12 is peripherally grooved as at |22 to form a notch and a latch projection |24 at the upper end thereof, for co-operation with a latch lever |26. The latch lever is adapted to be pivotally mounted on top end cap 66 of the interrupter chamber, for example, as by a pivot pin |26, and a coil spring |30 is wound about pivot pin |28 with the ends thereof engaging end cap 66 and latch lever |26, respectively, for biasing the latch lever in a clockwise direction about its pivot, as viewed in Fig. 1. The latch lever is provided with a plurality of latch lugs |32 and |34 for co-operation with the latch projection |24 on the upper end of contact piston rod 12, and with the core of solenoid coil ||2. A contact operating rod |36 is rigidly secured to contact piston rod 12 and extends from the upper end thereof through a sleeve |31 extending through the central opening of solenoid coil ||2 and securing sleeve ||4. The lower end of sleeve |31 is enlarged as shown at |38 to receive the upper end of a coil compression spring |44, with the lower end thereof bearing against the bottom wall of a tubular solenoid core member |40. The tubular solenoid core |40, which is of magnetic material, has the bottom wall thereof apertured to be slidably mounted on contact operating rod |36, and has adjacent the upper end thereof a peripheral inwardly extending rib |42 of a size to closely engage the outer surface of enlarged portion |38 of sleeve |31. Adjacent the lower end of solenoid core |40 are radially directed vent apertures |46, for a purpose to be hereinafter described.

In the operation of the mechanism thus far described, it will be apparent that upon the occurrence of predetermined circuit conditions, solenoid coil ||2 will become sufficiently energized to attract core |40 and cause it to move upwardly on operating rod |36 and compress spring |44 between the core and sleeve |31. Furthermore, because of the close iit between core |40, securing sleeve ||4 and enlarged portion |38 of sleeve |31, and since these parts are all immersed in the arc extinguishing iiuid, it will be obvious that upward movement of core |40 will be relatively slow because of the necessity of displacing the iiuid within securing sleeve I4 through the relatively small clearance between the core and sleeve. However, after sufficient movement of the core upwardly so that rib |42 clears the upper end of enlarged sleeve portion |38, there will then be a relatively large annular passage through core |40 and outlet apertures |46 for liquid entrapped in securing sleeve H4, so that further movement of core |40 upwardly will take place at a. relatively rapid rate. During this rapid movement of the core, the bottom wall thereof will engage the lower end of enlarged sleeve portion 38 to cause movement of the sleeve upwardly with the core, and engagement of the upper end of the sleeve with shoulder |41 formed on Contact operating rod |36, will thus quickly separate contact head 90 from fixed contact 18. This movement of contact head 90 by solenoid core |40 away from fixed contact 18 need be but a small amount, because as soon as the contacts are separated sufliciently to draw an arc, the pressure generated by such an arc operates to increase the contact separation sufficiently to extinguish the arc. Obviously because of the sliding connection of solenoid core 40 with respect to contact operating rod |36, the contact operating rod and contact head 90 are permitted to have a considerable overtravel independent of solenoid core |40 in response to pressures built up within the interrupter chamber 68. As soon as the arc is extinguished and the pressure drops within interrupter chamber 68, contact operating rod |36 is permitted to move downwardly to reclose the contacts. However, its downward motion is halted by engagement of latch projection |24 at the top of the contact piston rod 12 with upper latch lug |32. In the meantime, solenoid core |40 returns very slowly under the` biasing forces of gravity and spring |44, to the position shown in Fig. 1, because of the dashpot action thereof in securing sleeve ||4, so that considerable time must elapse until the solenoid core |40 moves down into engagement with the upper end of latch lever |26, and thereby causes counterclockwise rotation of the latch lever to disengage its upper lug |32 from contact piston rod projection |24. This permits the projection |24 to drop down slightly vwith contact operating rod |36, and into engagement with the lower lug |34 on latch lever |26, where it is held until further downward movement of solenoid core |40 causes further counterclomwise movement of the latch lever until projection |24 is released from lug |84, whereupon the contact head is permitted to move into engagement with xed contact 18. In-

1 cldentally, it will be noted Vthat upper lug |32 of latch lever |28 serves as the support for preventing undue downward movement of solenoid core |40.

The reason why a plurality of lugs |12, |34 are provided on the latch lever to successively halt downward movement of contact head 80 towards nxed contact 18 is that it is necessary to maintain the contacts separated, during the time delay period before reclosure, a sufiicient distance apart so that the dielectric therebetween will be capable of safely withstanding circuit voltage. Because of contamination and deterioration of the dielectric on the interruption of high current arcs, this distance is quite large. On the other hand, it is desired to make the time delay between a circuit interrupting operation and a reclosure of the circuit as long as possible with the available time delay means including the dashpot comprising solenoid core |40 and securing sleeve ||4. Lug |32 on the latch lever, therefore, is positioned to engage the moving contact to hold it separated from fixed contact 18 a distance corresponding to the safe gap therebetween according to the dielectric being used. If lug |34 were not also provided on the latch lever, then the time delay between a circuit interrupting operation and a reclosure of the breaker contacts would be too short, and accordingly, to lengthen this period, the second lug |34 is provided for momentarily delaying reclosure of the breaker contacts after release of the moving con tact from lug |32, to thereby obtain a longer time delay in reclosing without undue danger of flashover, inasmuch as the period of time which lug 534 operates to maintain the breaker contacts separated is so short that ionization of the path between the breaker contacts does not have time to be completed prior to reclosure of the contacts. Also on interruption of low currents, the pressure may be insumcient to move contact projection i 24 as high as latch lug |32 and since the dielectric will not be unduly impaired by low current interruptions, engagement with latch lug H34 will provide a safe gap between the contacts while using full time delay on reclosure.

The upper end of contact operating rod |36 is pivotally secured as by pivot pin |50 to one end of a pair of insulating links |48, with the other ends of the links being connected to an angled crank lever |52, for example, as by the pivot pin 53. Crank lever |52 is pivotally mounted at its other end on a shaft |54 extending across the hollow portion of the top cover casting, and its outer ends are mounted in apertures provided in the side walls 42 and 43 of the cover hollow portion, with the outer ends of these apertures being closed by screw plugs |58 to prevent relative endwlse `movement of shaft |54. Angled crank lever |52 is rotatably mounted on shaft |54, and a generally U-shaped yoke |58 has the leg portions thereof also rotatably mounted on shaft |54, with one leg of yoke |58 pivotally connected to one end of toggle links |60, and the other ends of these toggle links being pivotally connected to a toggle lever |68, which is, in turn, secured on the squared end of a shaft |88 rotatably mounted in an angled portion of end wall :i5 of the cover assembly in a bearing sleeve |12, by a bolt |10, which also acts to secure an operating handle |14 to the other squared end of shaft |88. Operating handle |14 is provided at the outer end thereof with a hook eye aperture |16 for the reception of a hook stick or other operatingr member. Actuating handle |14 is lim- 8 ited in its movement in a counterclockwise direction by a stop screw |18 which may be aecured in an adjusted position, forlexample, as by a lock nut |80.

A pair of concentric coil springs |82 and |84 are provided about shaft |54 within the hollow portion of the cover assembly 4, with one end |86 ofthe outer large diameter coil spring |84 engaging flange 88 of the cover assembly, and the other end |88 thereof engaging the connecting portion |89 of yoke |58, to thereby bias the yoke for movement about shaft |54 in a counterclockwise direction. This movement of the yoke is normally prevented by virtue of the toggle formed by links |50 and |88 being below their deadcenter position when actuating handle |14 is in engagement with stop screw |18. One end |88 of the smaller diameter inner coil spring |82 is extended to engage the angled portion of crank lever |52, and the other end of this spring a'so engages the connecting portion |88 of yoke |58, so that when the yoke is locked by toggle levers |60 and |56 against movement in a counterclockwise direction, biasing spring |82 will operate to bias crank lever |52 downwardly or in a clockwise direction relative to shaft |54, to thereby bias contact actuating rod |38 and contact head 90 downwardly, and cause engagement of the contact head with fixed contact 18.

The circuit through the interrupter herein disclosed extends from a terminal bracket |84 secured to the top cover assembly, for example, as by a screw |98 with the bracket having a terminal socket |96 for the reception of a line conductor, through the cover casting, by way of a conductor 200 to one tap ||9 of solenoid coll H2, through the coil, conductor 202 to contact piston rod 12, contact rod 86, contact head 9h. fixed contact 18, end cap 14, compression spring 84, terminal bolt 4, to another line conductor 28. Thus, it can be Seen that the solenoid coil |2 is connected in series in the circuit including the breaker contacts, and as shown, the whole coil is connected in series, inasmuch as the end taps of the coil are used, and, therefore, the connection is for the lowest rating of the breaker which can be obtained with the coil employed, inasmuch as the maximum flux generating capacity of the coil is employed to thereby obtain suillcient force to separate the contacts on relatively low currents. To obtain higher current ratings, it would be merely necessary to connect conductor 202 or 200 to other taps i8 of the coil to utilize smaller portions of the coil winding. It will be noted that the entire circuit breaker mechanism including the breaker contacts and interrupting chamber are supported as a unit with the casing cover assembly 4, so that they may be removed with the cover from the casing when desired by merely unfastening the securing means of the cover to support 34 on the casing. Another feature of the particular supporting means for the circuit breaker mechanism iliustrated is the specific support of the solenoid coil permitting ready replacement thereof by another similar coil, or by a coil having a different number of turns to thereby change the available ratings of the breaker. In order to remove coil H2, it is merely necessary to remove screws 52 holding U-shaped frame 60 and rectangular frame 64 together. This permits securing sleeve ||4 to drop downwardly out of U-shaped frame 60, and then by removing one pivot pin. for example, the pivot pin |50, the entire contact operating rod and sleeve |31 can be slipped out of U-shaped frame 80 through apertures in legs |08 and |08 of the frame, whereuponl coil Il 2 may be slipped laterally out of the open side of U- shaped frame 60. To insert a new coil, it is simply necessary to slide it in the open side of U- shaped frame 80 until the bore therethrough is aligned with the apertures in legs |06 and |08 of the frame, whereuponcontact actuating rod |36 and securing sleeve ||4 may be inserted through the apertures and through the bore in the coil, and rectangular frame 64 secured to the lower leg |08 of the U-shaped supporting frame to thereby firmly secure the solenoid coil in operative position. Consequently, in order to remove the coll. it is only necessary to remove two screws 62 and one pivot pin |50.

The operation of contact biasing spring |82 mounted on shaft |54 in cover assembly 4 is believed to be ,obvious from the foregoing. In other words, when the circuit is interrupted by energization of solenoid coil ||2 suiilciently to raise core and separate the contacts against the bias of spring |82, .this spring will be effective as soon as the circuit is interrupted to move the contact operating rod and contact head 90 downwardly towards lxed contact 18, until projection |24 on contact piston rod 12 is engaged by latch lug |32, whereupon reclosure of the contacts will be delayed until the latch is released by solenoid core |40 in the manner previously described.

In the event an overload occurs on the circuit which is not self-clearing but continues after a predetermined number of successive interrupting operations, there is provided means for tripping the toggle which normally prevents rotation of yoke |58, so that spring |84 becomes eiiective to rotate the yoke in a counterclockwise direction to the dotted line position shown in Fig. 1, and, consequently, raise crank lever |52, by engagement of the cross bar |88 of the yoke with a projection |9I on the lever, together with contact actuating rod |36 and contact head 80 to a position wherein the contact head is maintained out of engagement with fixed contact 18, because coil spring |82 will be ineffective to reclose the contacts. The means for tripping the toggle includes a cylindrical tube 204 threadedly mounted in the upper leg |06 of U-shaped support 60, and provided with an inlet aperture 208 in the bottom wall thereof controlled by a ball-check valve 2|0 to permit ow of liquid into tube 204, but preventing outflow of liquid. A piston member 206 is slidably mounted within cylindrical tube 204,

Yand the upper end thereof is provided with a plurality of spaced peripheral grooves 2|4, 2| 6, and 2|8, respectively, to form a ratchet-like portion on the piston accessible through a side opening 2| 2 in the cylindrical sleeve 204. A pawl guide rod 220 is also secured to leg |06 of U-shaped support 60 between cylindrical sleeve 204 and contact operating rod |36, for guiding a substantially U-shaped pawl member 222, having the connecting portion thereof slotted, as shown at 224 to receive the contact operating rod, and with the ends of the slot extending into the legs of the U-shaped pawlbut reduced in width, as shown at 226, to more closely lit guide rod 220.

lower leg of U-shaped pawl 222 to normally Contact actuating rod |36 is adapted to extend spring 230 engaging between washer 228 and the maintain the pawl in the position shown in Fig. 4.

In the operation of the circuit breaker, it will be observed that each time solenoid core |40 is drawn upwardly to open the circuit and engage the lower end of enlarged portion |38 of sleeve |31 to move the same upwardly, that it will cause a tilting of pawl 222 against the bias of spring 230, so that continued upward movement will move the entire piston upwardly and thereby unseat ball-check valve 2| 0 and cause a predetermined amount of liquid to be drawn in the lower end of sleeve 204. As soon as the circuit is interrupted, and the contactactuating rod and associated parts are moved downwardly by biasing spring |82 in the manner previously described, compression spring 230 on guide rod 220 is operative to withdraw the upper leg of pawl 222 from the notch 2|4 in piston 206, so that the piston remains at the position to which it has been moved, while the contacts are reclosed. Now if the fault on the circuit has been removed, piston 206 will gradually sink to the position shown in Fig. 4 by displacement of the liquid below the piston through the relatively small clearance between the piston and cylindrical sleeve 204, so that eventually it will attain its original position shown in Figs. 1 and 4. However, in the event the fault in the circuit has not cleared upon the rst reclosure of the breaker contacts, they will again be opened by solenoid ||2, and this timel pawl 222 will engage notch 2|6 in piston 206, as shown in Fig. 5, inasmuch as the piston will not have had time to sink to its original position and the piston will be moved upwardly to the position shown in Fig. 6 of the drawing. As soon as the arcis extinguished, the contacts will again be reclosed by biasing spring |82, and if the fault has cleared, piston 206 will again slowly sink to its original position as before. However, if the fault has not cleared before piston 206 has an opportunity to sink much below the position shown in Fig` 6, the contacts will again be opened, and this time pawl 222 will be pivoted into engagement with the lower notch 2|8 in piston 206 and cause the same to be moved upwardly a further amount and into engagement with the knee of the toggle formed by levers |60 and |66 to move the knee of the toggle over-center, thereby releasing spring |84 and permitting the same to rotate yoke |58 and move the toggle levers and contact operating rod to the dotted-line position shown in Fig. 1 of the drawing, wherein the breaker contacts are maintained by spring |84 in an open circuit position.

It will be observed that ordinarily actuating lever |14 is maintained entirely within the hood formed integral with top cover assembly 4, but upon tripping of the toggle constituted by levers |60 and |66, the actuating lever |14 will be moved in a clockwise direction about its pivot axis |10 to project below the hood, and thereby give a readily visible indication of the fact that the breaker contacts are now maintained in an open circuit position. When piston 206 has tripped the toggle, it will be observed that since contact operating rod |36 is maintained in an upper position, pawl 222 will be maintained in engagement with notch 2|8 on piston 206 to maintain the piston in its uppermost position. Accordingly, when it is desired to manually reclose the breaker contacts by movement of operating lever |14 in a counterclockwise direction to reset the toggle levers to the position shown in full lines in Fig. 1, it will be observed in the iirst place, that in the event it is thus attempted to close the circuit while an overload is present, the breaker is trip-free in that it is free to open against the bias of contact biasing spring |82 irrespective of the position of actuating lever |14. In the second place, it will be noted that since piston 200 has had but a little time to move downwardly from its outermost position with respect to cylindrical sleeve 204, that in the event the breaker is reclosed manually upon an overload in the circuit, that on the consequent circuit interruption and movement of the contact operating rod and associated parts upwardly, pawl 222 will be caused to engage the lower notch 2 i8 of piston 20E to thereby move the toggle overcenter and again permit spring |84 to maintain the contacts in an open position.

Thus, it can be seen that the circuit breaker herein disclosed is capable of automatically opening the circuit with an inverse time current characteristic due to the dashpot action of core |40 in securing sleeve i4, and yet the contacts are separated with a relatively fast action due to the venting of the dashpot formed by core |40 and sleeve H4 adjacent the end of its stroke. This feature is the invention of J. M. Wallace and is more particularly disclosed and claimed in his copending application Serial No. 399,453, illed June 24, 1941, now Patent No. 2,333,604, issued November 2, 1943, to the same assignee of this invention. Following a circuit interrupting operation, the breaker contacts are'automatically reclosed with a time delay also due to the dashpot action of core |40 and sleeve |14, while maintaining substantially to adjacent the end of the timed period a safe gap between the breaker contacts. Also, in response to a predetermined number of closely successive circuit interrupting operations, novel means are provided for maintaining the breaker contacts in an open position, which includes a biasing means normally held inactive by a toggle'i'vhich is moved overcenter by a piston actuated a predetermined amount upon each interrupting operation. The arc chamber herein disclosed is provided with an outlet valve which is positive in operation, and the electroresponsive solenoid contact opening means is supported in a manner to render the same readily replaceable, and is provided with a plurality of taps so that the rating of the breaker may be readily changed. The specific arrangement of the contact closing spring and the spring for maintaining the contact separated is especially important with respect to space considerations and efficiency of operation.

An operation counter 234 is adapted to be mounted on the end wall 45 of the hollow portion of cover assembly 4 and to be located be- Death the hood portion thereof so as to be readily visible from the exterior of the breaker while protected from the elements by the hood. This operation counter may be of any well known type provided with an actuating crank lever 23B, mounted on an operating shaft extending through the angled portion of wall 45 like shaft |68, and with crank 236 pivotally connected to an operating link 238, which, in turn, is connected to pawl 222, so as to actuate the counter on each circuit interrupting operation of the breaker. The connecting link 238 is provided with an insulating portion 240 to insulate the counter from pawl 222.

There is preferably provided within the hollow portion of cover assembly 4, in a socket 242 provided therefor on top wall 40, a lightning arrester assembly, which may be of any well known type including electrodes 256 spaced by an insulating plate 258 to form a gap in series with a porous block 260, in the circuit between top wall 40 of the cover and terminal 244 oi the assembly. A tubular insulating sleeve 262.l is positioned between the assembly and the side wall of socket 242, and insulating disk 210 supports terminal 244 and is secured to the cover assembly 4 by screws 26E, with a sealing gasket 204 therebetween to maintain the arrester assembly in socket 242. A shunt 260 connects terminal 244 and a contact plate 21|, and this plate is maintained in contact with block 260 by a spring 212. The arrester terminal 244 is connected by conductor 248 to the top leg |06 of U-shaped frame 60 to thereby form a circuit by-passing solenoid coil ||2. This obviously will prevent the solenoid coil from opening the breaker contacts in response to surges inasmuch as the coil will cooperate with the shunt circuit through the arrester assembly to by-pass such surge currents around the coil and limit the voltage across the coil insulation, and such surges will be ineiective to cause a circuit interrupting operation of the breaker. The arrester assembly herein disclosed utilizes a single series porous block and gap of the type shown in the plural series block and gap arrester shown in the patent to L. R. Ludwig, et al., No. 2,135,085, issued November l, 1938. It will be understood that plural series porous block and gap assemblies may be used with this circuit breaker, if desired.

Also positioned beneath the hood portion of the cover assembly is a. tubular sight gauge glass 250, held in position against an integral lug 240 on end Wall 45 of the cover assembly, by an apertured threaded plug 249, and an indicating rod 252 is slidably mounted through the apertured plug and tubular sight glass, and is provided with a float 254 secured to the lower end thereof Within casing 2 so that the level of liquid within casing 2 may be readily determined from the exterior thereof by inspection of the sight glass beneath the hood portion oi the cover assembly.

Thus, there is provided in a single unit an automatic reclosing circuit breaker characterized by its ability to automatically maintain the breaker contacts in an open circuit position in response to faults which continue a predetermined period of time, and by its inverse time current tripping characteristics with predetermined time delay in reclosing of the circuit, together with means incorporated in the unit to protect' the coil insulation and prevent operation of the breaker in response to the occurrence of surges in the circuit. Moreover, the cover assembly for the breaker casing 2 is arranged with a sleet hood portion at one side thereof to conceal an operating handle which is projected into view upon lock-open operation of the breaker contacts to indicate this condition, and also houses liquid level indicating means, as well as means for indicating the number of breaker operations.

Having described a preferred embodiment of this invention in accordance with the patent statutes, it is desired that it be not limited to the particular embodiment herein disclosed, inasmuch as it will be obvious, particularly to persons skilled in the art, that many changes and modifications may be made in this particular embodiment without departing from the broad spirit and scope of the invention. Therefore, it is desired that the invention be interpreted as lconstitute supporting means extending into said casing, separable contacts mounted on at least ,one of said members so as to be engaged at one point along said supporting means, at least one `of said members at another point along said supporting means dening a side opening, said one member having aligned apertures at opposite sides of said opening, a removable solenoid coil having a bore, said coil positioned in said opening with the bore thereof aligned with said apertures, a core guide tube extending freely through one of said apertures and freely through said bore into engagement with said one member at the opposite side of said opening to prevent removal of said coil, a core for said coil mounted for movement through said tube, said core operatively associated with one of said contacts to actuate the same, and at least another of said frame members detachably secured to said one member at the end thereof having said one aperture and having a portion overlying the adjacent end of said guide tube to prevent withdrawal thereof.

2. In a circuit breaker of the type described having current interrupting means including separable contacts, electroresponsive means for separating said contacts including a solenoid coil having a substantially central opening for cooperation with core means operatively associated with at least one of said contacts; the combination of means for unitarily supporting said first two-mentioned means including relatively rigidly associated supported frame members, one of said members being of open general U-shape in form for removably receiving said coil with the legs oi' said ,U-shaped member being apertured in alignment with said coil opening, a core guide tube adapted to be freely insertedv through the aperture in one leg of said U-shaped member and the opening of said coil to engage the other leg of said U-shaped member, and detachable means preventing movement of said tube outwardly of said apertures comprising means detachably securing another frame member to said one leg with portions of said other frame member overlying the adjacent end of said tube.

3. In a circuit breaker of the type described having current interrupting means including sep arable contacts, electroresponsive means for separating said contacts including a removable solenoid coil having a substantially central opening for co-operation with core means operatively associated with at least one of said contacts; the

combinationof means for unitarily supporting said rst two-mentioned means including relatively rigidly associated supporting frame members, one of said members being of open general U-shape in form for receiving said coil with the legs of said U-shaped member being apertured in alignment with said coil opening, securing means adapted to be freely inserted through the aperture in one leg of said U-shaped member and the opening of said coil to engage the other ieg of said U-shaped member for preventing escape of said coil from said U-shaped frame member, and means preventing escape of said securing means outwardly of said apertures `comprising means detachably securing another frame member to said one leg'with a portion of said other frame member overlying the adjacent end of said securing means.

4. In a circuit breaker of the type described having current interrupting means including `separable contacts, electroresponsive means for separating said contacts including a removable solenoid coil having a substantially central opening for co-operation with core means operatively associated with at least one of said contacts; the combination of means for unitarily supporting said first two-mentioned means including relatively rigidly associated supporting frame members, one of said members being of open generalv U-shape in form for receiving said coil with the legs of said U-shaped member being apertured in alignment with said coil opening, securing means adapted to be freely inserted through the aperture in one leg of said U-shaped member and the opening of said coil to engage the other leg of said U-shaped member for preventing escape of said coil from said U-shaped.

frame member, said securing means being unsecured to said U-shaped member, and means preventing escape 'of said securing means outwardly of said apertures comprising means detachably securing another frame member to said one leg of said U-shaped member.

JAMES M. WALLACE. HERBERT L. RAWLINS. JAMES M. CUMMING. WAYNE S. ASPEY.

REFERENCES CITED The following references are of record-in the ille of this patent:

UNITED STATES PATENTS Number Name Date 894,237 Stivers July 28, 1908 1,180,914 Gengenbach Apr. 25, 1916 1,199,046 Bliss Sept. 26, 1916 1,336,069 Conrad Apr. 6, 1920 1,394,087 Heinrich Oct. 18, 1921 1,650,799 Lee Nov. 29, 1927 2,163,559 MacNeill June 20, 1939v 2,391,277 Stapleton Dec. 18. 1945

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