US2449867A - Circuit interrupter - Google Patents

Description

Sept. 2l, 1948. 2,449,867

J. M. WALLACE CIRCUIT INTERRUPTER Filed July 12, 1,940 2vSheets-Shcet l f @ggg .6 2'* i Y @l 7 Jaaa falmmusv Sept 2l, 1948. J. M. WALLACE CIRCUIT INTERRUPTER 2 Sheets-Sheet 2 Filed July 12, 1940 WITNESSES:

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BY 'Wi/ff ORNEY Patented Sept. 21, 1948 CIRCUIT INTERRUPTER James M. Wallace, North Braddock, Pa., assignor to Westinghouse Electric Corporation. East Pittsburgh, Pa., a corporation of Pennsylvania Application July 12, 194`0, Serial No. 345,051

(Cl. o-89) 2l Claims. l

, My invention relates to circuit interrupters, ln general, and more particularly to circuit breakers of the automatic reclosing type.

One object of my invention is to provide a. circuit breaker with novel means for automatically opening and then reclosing its contacts a predetermined time after the opening opera-tion.

My invention` is particularly directed 'to sosalled small oil circuit breakers of the type where the circuit is interrupted in an arc extinguishing liquid such as oil, and where the operating mechanism is relatively simple and compactly arranged so that the whole device may be arranged, preferabiy, in an insulating casing having a pair of terminals. for easy and convenient mounting on a pole or other support for transmission and distribution lines.

The circuit breaker of my invention is especially adapted for the replacement of fuses used for the protection and maintenance of service on transmission lines. Such a circuit breaker may be mounted on the same support required for fuses. and has the advantage over simple fusainstallations of being able to quickly restore service on the protected line following self-clearing faults. This type of circuit breaker has the further advantage over all types of fuse structures including repeating fuse structures, of not requiring the replacement lof any parts following an interrupting operation. In fact, the circuit breaker of my invention will require substantially no attention until a permanent fault appears on Athe circuit protected, and after such a fault has been cleared, only a simple manual manipulation is required to restore the breaker to operative condition.

Although I have designed my invention for a -rupter; novel tripping means designed to provide different tripping characteristics for successive circuit opening operations of the interrupter.

It is desirable for coordination with transformers, fuse links and other circuit breakers, that the first tripping of an automatic reclosing circuit breaker be a time delayed trip, especially on lig-ht overloads, inasmuch as such overloads cannot harm a circuit provided they are not continued 2 too long. However, if the fault is permanent. lthe succeeding trips should be substantially instantaneous to prevent damage to the circuit, and operation of other protective devices.

Another object of my invention is to provide in a circuit breaker, novel means operative in response to overloads for first slightly separating the breaker contacts, and for thereafter utilizing pressure developed by lthe arc f-ormed for funther separating said contacts.

Another object of my invention is to provide novel tripping means for a circuit breaker operable in response to overload currents vfor separatlng the breaker contacts.

Another object of my invention is to provide a novel type of interruption chamber for a circuit breaker which is especially adapted to utilize pressures generated by the arc to aid in separating the breaker contact-s.

A further object of my invention is to provide novel circuit breaker operating mechanism, which is operable to close the breaker contacts auto'- matically a predetermined time following a circuit interrupting operation.

Another object of my invention is` to provide in an automatically reclosing type of circuit breaker, novel means for predeterm-ining the number of successive reclosures, after which the breaker contacts are maintained in an open circuit position.

A still further object of my invention is to provide an automatic reclosing type of circuit breaker with novel means for maintaining the breaker conta-cts separated in response to a ypredetermined number of successive reclosures thereof, but which is ineffective to Amaintain said contacts separated in response to any' number of nonsuccessive reclosures.

Another object of my invention is to provide a circuit breaker having contacts separable in an arc chamber, with novel means for flushing said chamber Iafter each interrupting operation.

Another object of my invention is to provide a circuit breaker of the type described having a novel construction and arrangement of parts such as to provide a smaller, lighter, and more economical lbreaker than has heretofore been deemed practical.

These and other objects of my invention will become more apparent upon consideration of the following specification of preferred embodiments thereof, taken in connection with the attached drawings, in which:

Figure 1 is a substantially central longitudinal sectional View through a circuit interrupter constructed in accordance with my invention;

Fig. 2 is a partial sectional view of the upper end of the interrupter shown in Fig. 1, and illustrating certain parts of the operating mechanism in elevation and in a position corresponding to an open position of the interrupter;

Fig. 3 is a side elevational view partly in section of the operating mechanism shown in Fig. 2 and taken substantially along the line III-III of Fig. 2;

Fig. 4 is a cross-sectional view through the arc chamber shown in Fig. 1, and substantially on the line IV-IV of Fig. 1;

Fig. 5 is a partial cross-sectional view of the upper end of an interrupter similar to that shown in Fig. 1 but illustrating a modified form of tripping mechanism; and

Fig. 8 is a partial central cross-sectional view of the interrupter shown in Fig. 5 taken substantially at right angles to the plane of Fig. 5.

In general, my invention is embodied in a circuit interrupter having a pair of separable contacts which are initially separated a distance sufficient to draw an arc between the contacts in in an arc chamber. which chamber is designed to be filled with an arc-extinguishing medium such as oil or the like, and the contacts are arranged so that the pressure generated by the arc and due to the decomposition of the oil operates to further separate the contacts against the bias of a spring which normally maintains the contacts closed. As soon as the arc is extinguished, the spring is then free to reclose the contacts, but its action is retarded by a time delay means operable only when the contacts are closing. This time delay means is related to the contact closing means in such a manner as to permit a predetermined number of successive reclosures. For example, upon the occurrence of a permanent fault on the line the time delay means will act to lock or maintain the contacts in an open position following a predetermined number of reclosures thereof.

I will disclose herein two species of current responsive means for initially separating the contacts to establish Van arc therebetween. In one embodiment of my invention the contact which is normally stationary is mounted for limited movement to and from the movable contactunder the influence of a solenoid connected in the circuit. In another form of my invention, the movable contact is mechanically moved by a spring or other biasing means a short distance in response to operation of current responsive latch means for the biasing means. My invention further contemplates the' use of a pair of latch means for the mechanical contact tripping means, with each latching means being operable in response to predetermined current conditions in a circuit and having different time characteristics. These latch means are so arranged that successive interrupting operations of the circuit breaker without appreciable time between successive interruptions, foi example, as on the occurrence of a permanent fault in the circuit, will occur with different time characteristics.

Referringto Figures 1 to 4 ofthe drawings, I have illustrated one form of my novel circuit breaker as being contained in an insulating tubular casing 2, which may be oi' any desired insulating material, such as porcelain, glass, or the like. The casing 2, as shown in Fig. 1, has a closed bottom end portion and an open top. The open top is provided with an upper( terminal lend of the casing 2.

cover assembly 4, and the closed bottom of the casing is provided with a lower terminal assembly l. An intermediate portion on the casing has a substantially cylindrical wall portion 8A upon which is mounted a cushioning sleeve I2 of rubber. fiber or the like, and on opposite sides of which may be clamped supporting. brackets i2 (only one ,of which is shown), as by bolts i4. The outer end of bracket l2 may be turned laterally at i1 and apertured as at I6 for the reception of a bolt for securing the brackets in position on a pole or other supporting structure.

The lower terminal assembly 6 is mounted at the closed bottom portion of the insulating casing 2 by means of a bolt I l extending through an aperture i8 in the closed end of the casing 2, and the bolt is provided with an enlarged disclike head portion`20 positioned within the casing 2, with packing material 22 interposed between the head 20 and the adjacent inner surface `of the closed end of the insulating casing 2. The packing material 22 may be of any desired packing material, preferably one resistant to oil, such for example, as cork, fiber or synthetic rubber. Bolt I2 has a bore Il therethrough, theouter end of which is closed by a threaded plug 2l, for the purpose of draining casing 2 when desired. The bolt i2 is secured in position by a nut 24 drawn up on the bolt against a washer 26 positioned between the nut 24 and the outer wall of the closed A terminal strap 2l may be also secured to the bolt Illas by means of a second nut 20. as shown.

The upper terminal assembly 4 is in the form of a cover for the open end of the casing 2, which not only acts as a cap or cover for the casing, but. as will be hereinafter more fully explained, acts as a support for the interrupter and its operating mechanism when in operative position within the casing 2. Referring to Figs. 1 and 6,

. it will be noted that the cover 32 is provided with a transversely extending relatively hollow portion for the reception of certain parts of the circuit breaker operating mechanism, and the top 'wall of which is provided with an aperture for the reception of a screw threaded filler plug 24, so that the supply of arc-extinguishing fluid within the casing 2 may be renewed when necessary. The cover 22 includes a .peripheral flange portion 38 adapted to seat on the upper end walls of casing 2, and this flange has at its outer edge a downwardly turned lip portion 3l, for properly positioning the cover on the open end of the casing 2. Packing material 40 is interposed between the cover and the open end of the casing similar to the packing material 22. and the cover I2 is secured to the casing 2 by means of a support 42 flxedly mounted on the outside of the casing 2. The support 42 is in the form of an annulus which is substantially channel-shaped in crosssectlon, with the channel facing the outer surface of casing 2. The annular support 42 is secured to the casing by cast metal or the like 44, which is poured in between the support 42 and the outer casing wall so as to enter within the channel of the support 42 and between corrugations 48 provided on the outer surface of the casing to securely anchor the support 42 thereto. I provide a plurality (only one of which is shown) of laterally extending ears I0 and 82 on the support 42 and cover flange. 2B, respectively. which ears are apertured for the reception of bolts 4l for securing the cover to the supporting 1fllagnge 42. and. therefore, te the insulating c.

The insulating casing 2 may be of any desired shape and cross-section, preferably circular as.

to the segments 54 of the cover flange 36, byumachine screws 51, with interposed insulating washers 58, and insulating bushings 60. Theinsulating washers 58 and bushings 60 may be of any desired insulating material such as fiber, or a synthetic resin material. As shown, the supporting plates 56 extend substantially parallelly downwardly in the tubular insulating casing '2, and onel function of these plates is to support a substantially closed arc chamber 62, the upper end of which is secured between the lower ends of the supporting plates 56 in any desired manner,

such, for example, as by welding or the like.

Thearc chamber 62 includes an insulating tubular portion 64 which may be of any desired insulating material preferably ber or a synthetic resin, which tube is threaded at each end thereof for the reception of upper and lower end caps 66 and 68, respectively. The upper end cap 66 is provided with anv integral offset portion provided with a substantially cylindrical open-topped cavity therein to form a dashpot cylinder l which will be hereinafter further described. The

upper end cap 66 is also provided with an aperture 12 centrally located' with respect to the tubular chamber wall 64 and through which a contact rod 14 is slidably mounted. The contact rod 14 preferably closely slidably ts within the aperture 12 so that there will be substantially no leakage of pressure from the arc chamber 62 at this point. The contact rod 14 obviously may be constructed of any desired conducting material, such, for example, as copper or a copper alloy.

, The contact rod 14 is provided adjacent its lower end with peripherally spaced, longitudinally extending grooves 16 for a purpose to be hereinafter further described.

The upper end of the movable contact rod 14 is provided With a pivot pin 18 extending transend of a crank lever 86. The insulating link 62 may be of any desired insulating materialfsih, for example, as fiber, a synthetic resin orthe like. The crank lever 86 is fixed on an operating shaft 88, the opposite ends of which are journalled in opposite sides of the hollow portion of the cover 32, with one end of the operating shaft 88 extending through the cover wall to have xedly mounted thereon a manual operating handle 90 having a downwardly extending operating portion 92, adapted to be engaged by manual operating means, such, for example, as a hook stick or the like. The crank lever 86 is normally biased for movement in a counterclockwise direction about the axis of operating shaft 88, by a coil spring 94 coiled about the operating shaft 88,

and having opposite ends thereof 96 and 6l, engaged with portions of cover 32 and crank lever 86, respectively. This biasing action of coil spring 94 obviously tends to maintain the movable contact rod 86 in a position adjacent the bottom of the arc chamber 62.

'Iime delay and lockout mechanism for the circuit breaker contacts are provided for delaying the closing time of the contacts under the in- Iluence of coll spring 94, and for maintaining the contacts out of engagement after a predetermined number of quickly succeeding circuit interrupting operations. The time delay means for the contact closing operation utilizes the dashpot cylinder 10 provided integral with the upper end cap 66 of the arc chamber. This cylinder 10v is adapted to receive a piston member having some slight clearance in the cylinder, so as to permit the escape of fluid trapped between the piston 95 and the bottom of the cylinder at a predetermined relatively slow rate. As shown, the lower portion of the piston 95 is hollowed out as at 91 for the reception of a coil compression spring 99, seated at one end on a metal washer |0| on the bottom of the cylinder 10, and the other end of spring 99 bearing against a similar washer |03, provided at the top of the hollow portion 91 in the piston. The spring 99 obviously functions to normally maintain the piston 95 in an extended position with respect to the cylindrical portion 10, normally the position shown in Fig. 1 of the drawing. The piston 95 is preferably of insulating material, such, for example, as fiber or a synthetic resin material.

A pair of ratchet links |00 have one end thereof pivotally mounted at opposite sides of the upper end of piston member 95, as by the pivot pin |02. The other ends of ratchet links |00 are connected by means of ya guide pin |04, and one longitudinally extending edge of each ratchet link |00 is provided with a series of notches |06, for cooperation with a pawl to be described. A pawl link |08 is provided with a longitudinally extending slot ||0, through which extends the guide pin |04 positioned in holes in the ratchet links |00 for guiding the pawl link |08 for movement with respect to the ratchet links |00. The pawl link |08. as shown, yis located between the ratchet links |00, and has secured to opposite edges adjacent the lower end thereof, as shown in Fig. l, by welding or the like, astop bar ||2 and a pawl bar H4. respectively. The stop and pawl bars ||2 and ||4, respectively, act to limit pivotal motion of the pawl link i 08 about guide pin |04 with respect to ratchet links |00, and longitudinal movement of the pawl link with respect to the ratchet links is limited, of course, by the extent of guide slot ||0. The upper end of pawl link |08 is pivotally mounted between a pair of crank arms ||6 by a bolt ||8 extending therethrough, which bolt is provided with resilient substantially cup-shaped washers |20 at ea-ch end thereof to provide a frictional pivotal connection between the crank arms ||6 and the pawl link |08. The crank arms ||6, as shown, are lsecured to opposite sides of the crank lever 86, for example, as by welding or the' like, so as to move therewith. The flange 36 of cover `32, as shown in Fig. 1, is provided with an integral downwardly extending lip portion ||1 which extends downwardly along the inner wall of the insulating casing 2 to support an adjustable stop screw I9 for a. purpose tofbe hereinafter described.

In the operation of the mechanism described above, assuming that the movable contact rod 14 is moved upwardly in response to an overload or v other fault condition occurring in the circuit, it is obvious that crank lever Il will be moved in a clockwise direction, thereby stressing coil spring 04, and also causing movement of the crank arms H in a clockwise direction. Because of the frictional pivot H0 between the crank arms |I0 and the pawl link |00, the stop bar Il! on the link will be maintained in engagemen-t with the smooth edge of ratchet links |00. Dashpot piston Il will remain substantially in the position shown in Fig. l, and the pawl link |00 will be withdrawn slightly from between the ratchet links |00. This movement continues until the end of the opening movement of contact rod 1I. When the opening means is no longer eiective, obviously, coil spring 04 can then operate to move the crank lever 8l in a. counterclockwise direc- 'tion about the axis of shaft Il to move the contact rod 'Il downwardly, and to move the crank levers IIB in a counterclockwise direction.- This movement of the crank levers iii will also move the pawl lever |00 through frictional pivot III, to bring the pawl bar Ill into engagement with one of the notches |00 in the ratchet levers |00. This position of these levers is illustrated in Fig. 2 of the drawings, wherein the pawl bar lll is shown as in engagement with the secondrnotch from the lower end of the ratchet links |00. As shown in Fig. 2, the guide pin |04 is in a position below the upper end of the guide slot ||0 in the pawl link |00. Continued movement of the crank lever Il .under the influence of coil spring 04 will tend to straighten the toggle formed by crank arms ||0 and links |00 and |00 and thereby move the dashpot piston 05 a predetermined distance downwardly into the dashpot cylinder 10. This movement will be relatively slow due to the opposition oifered by the dashpot piston and cylinder, and due to the. fact that the toggle formed by crank arms i i8 and links |00 and |00 is at the beginning of this movement, a considerable distance away from dead-center position. The resistance oiered by the dashpot piston and cylinder, of course, is due to the necessity of displacing the ,oil entrapped in the dashpot cylinder I0 through the small clearance existing between the dashpot piston 95 and the inner wall of the cylinder 10. However, as closing movement of the mechanism proceeds further. the toggle mentioned above -approaches its dead-center position, and, consequently, less force need -be applied to this toggle because as the lowei limit of movement is aD- proached. the dashpot piston 9S is moved a lesser extent for the same amount of rotating movement of operating shaft 80. Inasmuch as the closing force exerted by coil spring 00 is constant, it is obvious that the speed of closing movement is relatively slow at first due to the position of the toggle previously mentioned, but speeds up as it approaches the closed position shown in Fig. l, because the toggle approaches its dead-center position. This action will enable the circuit breaker contacts to go into final closed position with substantially a snap action, which is obviously desirable, to reduce arcing when the contacts are closed.

It will be noted that as the crank arms IIB and pawl and ratchet links |00 and |00 approach the position shown in Fig. l, that these links go into and past their dead-center positions, and this latter movement operates to bring the righthand edge of pawl link |00 as seen in Fig. l into engagement with the adjustable stop screw Ill, and thereby force the pawl bar ||4 out of lthe notch |00 in which it had been engaged. and

thereby release the dashpot piston 0l to permit it to begin its upward travel to normal position under the influence of spring Il.

When the parts have reached the position shown in Fig. l, which corresponds to the closed circuit position of the breaker, if the fault on the line has not been cleared, the movable contact rod 10 will substantially immediately be caused to move upwardly again to open the circuit. This will cause the parts to move as before, excepting that when the upper position of the contact rod 14 is reached, or when the limit oi clockwise rotation of the crank lever 00 is attained, and the reverse or closing movement begins, pawl bar III will engage the third notch from the bottom of the ratchet levers |00. This is because of the length of time required for spring Il to move dashpot piston Il upwardly, so that it will not have attained its normal extended position shown in Fig. 41 by the time the breaker starts to reclose on a.4 second substantially immediately succeeding reclosure. With the pawl bar Ill engaged in the third notch in the ratchet levers, the parts will then proceed to reclose as before with the dashpot piston Il this time being forced a further distance into the dashpot cylinder l0. If the fault still remains on the circuit, the circuit breaker will again open and reclose in the manner described above, except that this time the pawl bar I I4 will be engaged in the next succeeding higher notch in the ratchet links |00 and, accordingly, the dashpot piston 05 will be pushed a greater distance into the dashpot cylinder 10. vIf the fault still has not been cleared, the movable contact rod'll will again move upwardly to interruptl the circuit. and this time upon attempted reclosure, the pawl bar ill will engage in the upper notch in the ratchet links |00, and counterclockwise movement of the crank lever I0 will be arrested after a slight movement, due to the dashpot piston l5 striking the bottom of dashpot cylinder 10, and the movable contact rod 14 will thereby be locked or maintained in an open position.

I have described above, a lockout means which operates to maintain the circuit breaker contacts open after three closely successive reclosures of the contacts. This number has been chosen because it has been found that the great ma- .iority of faults which are self-clearing will clear in the time necessary for two or three successive reclosures of my breaker. However, it is obvious that any desired number of reclosures may be provided before the breaker locks out, merely by adjusting the dimensions of the dashpot cylinder and piston, and providing an appropriate number of notches in the pawl links |00.

To reset'l the breaker after the contact rod 14 has been locked out and maintained in an upper position, it is merely necessary to rotate the manual operating handle in a clockwise direction about the axis of shaft 00. AV very slight rotation of the cranklever 00 by virtue of the frictional pivot lil, will cause pawl bar ||4 to disengage the upper notch |06. It will be noted that this operation is easily accomplished because the only load on the pawlbar Il is the relatively light spring load 99, and this load will not even be present if theoperating rod 00 is moved quickly. With pawl III disengaged from the upper notch |00, dashpot piston II is free to move upwardly and in a very short time (the time required for the piston to travel the distance between adjacent notches |00), the opertion shown in Fig. l in the manner describedv above.

Obviously. if the fault clears after the first or second closely succeeding interrupting operation, and the circuit is reclosed,` the dashpot piston 88 will be moved upwardly after a predetermined time by the coil spring 88 to its normal position shown in Fig. 1, and the contacts are locked open only after three closely successive interrupting operations, and will never be locked open irrespective of the number of tune-spaced interruptions.

'Referring to Fig. 1, the contact opening means is mounted on the lower end of arc chamber 82, specifically on the lower end cap 88 of the chamber. The end cap 88 of the chamber is provided with an aperture |28 forming an extension of the passage through insulating tube 84, and which forms between the aperture |28 Iand the threaded flange of the end cap 88, a shoulder |22 Abetween forming a guiding bearing for slidably receiving a contact rod 80 which cooperates with the movable contact rod 'I4 to -control the electric circuit through' they interrupter. A Vsubstantially U shaped operating coil yoke |84 of magnetic material, such as soft iron or the like, has one leg thereof secured to end cap 88 of arc chamber 82 as, for example, by machine screws |82 with spacer dicss |88 interposed between the end cap 88 and the adjacent leg of yoke |84. The legs of yoke |84 are provided with aligned Vapertures for receiving a guide tube |88, the passage through which is aligned with the bearing formed by flange |28 for slidably guiding the outer end of contact rod |30. Movement of the contact rod |30 outwardly ofthe Iarc chamber 82 is limited by an insulating block |88 secured to the bottom les of yoke |84 by machine screws |40, tocover the lower end of guide tube |88. As shown, the lower end of contact rod |80 is hoiiowed out to receive a coil compression spring |42, one end of which engages the insulating block |88, and the other end of whichengages a metallic disc i 48 in the .bottom of the hollow portion |44, to normally Referring to Fig. 6 of lthe drawing, it will be apparent that cover 82 for interrupte'r casing 2 is yprovided with an angle piece |88, one leg of which is secured to flange 88 of the cover as by screws |88, and the other leg of which has secured thereto, as by welding or the like, a conductor terminal socket |82, having a clamping screw |84 threadedly enaed through the outer wall thereof to clamp a conductor in the socket |82.

The electrical circuit through the interrupter shown 'in Figs. 1 lto 4, inclusive, may now be traced from the terminal socket |82 on cover 82. through the cover, conductor |88, to movable contact 14, contact rod |88, loweren d cap 88, conductor |88, solenoid coil |48. conductor |84. resilient contact strip |82, bolt I8 of the lower contact assembly 8, and terminal strap 28 tol another line conductor.

Upon the occurrence of an overload in the circuit in which my interrupter is connected, obviously if the overload .is greater than a predetermined value, it will cause solenoid coil |48 to draw the contact rod |80 downwardly to substantially the dotted line position shown in Fig. l. vIt will be noted that the upper end of contact rod |88 has a full central circular portion |88 spaced from the upper end thereof, and above and below this central portion |88 are providedv spaced longitudinally extending grooves for thepurpose of venting the arc chamber. The contact rod |80, or dt least a lower portion thereof, is of a conducting magnetic material, such, for example, as iron or an alloy thereof. When the conductor rod |88 is attracted to the dotted line position by the solenoid coil |48, the full central section |88 of the contact rod will be positioned opposite the flange l|28 on the lower terminal cap so as to close oil the lower end of the arc chamber 82. Movable contact rod 14 may, due to any play which may n with an arc-extinguishing liquid, such as oil, up

urge the contact rod |80 upwardly into engage; l

ment wtih the stop washer |24. Confined between the legs of the U-shaped yoke |84, and wound about guide tube |88, is a coil |48, one end |84 of which is connected to a terminal screw |80, threaded into the outer lower surface of the insulating block |88. The screw |80 also functions to secure to the block in conducting relation to the conductor I 84, a curved substantially U- shaped resilient contact strip |82, which, as shown, is adapted to engage the enlarged vhead 20 of bolt |8 of the lower-terminal assembly 8 of interruptor casing 2.

The other end of coil |48 is electrically connected by a conductor |88 to the lower end cap 88 of the arc chamber. Movable contact rod 14 is electrically connected by conductor |88 to the interrupter casing cover 82. as by having theends of the conductor soldered or otherwise connected to these parts. respectively.

to a level indicated by the dash line L, and consequently the arc chamber 82 is completely filled with such liquid. The arc formed will generate gases due mainly to decomposition of the arc-extinguishing fluid, and inasmuch as the arc chamber is substantially closed, the' pressure generated therein by such gases will operate to move the contact rod I4 upwardly in a piston-like manner, out of the arc chambenyand move the mechanism associated therewith against the bias of coil spring '84 to produce a large gap between the contact rods 14 and 80. If the overload is of a large magnitude, solenoid coil |48 and the gas pressure built up in arc cham-ber 82 may have sufficient force to move the contact rod against the bias of spring |42 downwardly below the dotted line position shown in Fig. 1 to the limit of its travel in -a downward direction against insulating block |88. This will move the full circular section |88 of the upper end of contact rod|80 below the flange |28 on end cap 88, so as to bring the slots |88 in the upper end ofthe contact rod |80 adiaoent the flange '|28 so that venting of the arc 8888s may take place through the passages thus created and through the space between the upper leg of yoke |34 and end cap 68. The lower contact |30 thereby functions as an overpressure relief means to prevent damage to the arc chamber in interrupting high current arcs. When the circuit has been interrupted and the arc gases dissipated by the venting means described above and by a vent created by the moving contact 14 at its upper limit of travel by presentationv of grooves 1E in the lower end of this contact rod adjacent the aperture 12 in the upper arc chamber end cap 56, spring |42 will move the contact rod |30 upwardly against the stop washer |24 to the position shown in Fig. 1. It is seen that in this position of the contact rod |30 new vent passages similar to the passages described above are created, by the grooved portions |88 of the rod below the full circular section |88 thereof, being presented 4adjacent to the iiange |28 on the lowerend cap 68. Inasmuch as at this time the upper contact rod also is in a venting position with respect to the upper end of the arc ch-amber 62, the arc gases will be permitted to escape from the arcing cham-ber,l and under the influence of the head of arc-extinguishing liquid, liquid may ow in the bottom venting .passages to replace the are gases escaping from the top of the arc chamber, thereby providing for flushing out of the arc chamber `after each interrupting opera/tion and replacement of the used arc-extinguishing liquid with new liquid from the reservoir maintained in insulating casing 2.

Following this venting and flushing out of the -arc chamber S2, the circuit breaker contact rod 14 is moved downwardly and into engagement with the contact rod |39 by coil spring 84 with the time delay and inal snap action, all as previously described. lf the fault is cleared when the circuit breaker contacts reclose, the dashpot piston 05 resets as previously described. On the other hand, if the fault stili exists, solenoid coil |48 will operate to again open the contacts, and contact rod 'it will be forced upwardly as for the iirst opening described above. The operating mechanism will then operate to reclose the contacts a predetermined number of times if the fault coritinues, until the contact rod 14 is locked in an upper open position4 by the lockout means, all as previously described.

Instead of providing for movement of the lower contact by a solenoid coil |48, as described above, I may provide current-responsive means for moving the upper contact rod 14 slightly upwardly to establish an arc, and -then rely upon pressure in the arc chamber to continue movement of this rod to its fully open position. With such a structure, obviously ythe lower Contact may be fixed with respect to the arcing chamber 82. Such a construction Als the joint invention of H. L. Rawlins and myself, and is disclosed and claimed in our joint application Serial No. 346,306, tiled July 19, 1940, now Patent No. 2,318,421, issued ilziiday 4, 1943, to the same assignee of -this applicaon.

Referring to fFigs. 5 and 6 of the drawings, I have shown such a construction embodied in a circuit breaker of the automatic reclosing and lockout type previously disclosed, and, accordingly, like parts are provided with like reference numerals. As described in the above mentioned copending application, a trip lever is provided for initially moving the contact rod 14 upwardly a short distance to establish an arc within the arc chamber 62. This trip lever |10 is substantially hook-shaped in form and is pivotally mounted adjacent the point of the hook on a pivot'pin |12, mounted between the supporting plates 58 for the arc chamber 82. A cdil spring |14 is provided about the pivot pin |12, and has one end .thereof |18 engaging with the upper end cap 88 of the arc chamber, and the other end thereof |16 is engaged with a part of the trip lever |10 extending beyond the pivot- |12, to continuously bias the trip lever |10 for rotation about its Divot pin |12 iin a counterclockwise direction. As shown, the pivot pin 18 joining the upper end of contact rod 14 and insulating link 82 is received substantially in the bight portion of the trip lever |10, so that it is engaged 4by the lever when the lever is moved by spring |14 from the position shown in Fig. 5, to thereby move the contact rod 14 upwardly a slight distance against the bias of spring 84. The upper end of the trip lever |10 is provided with a projecting catch .portion |00 secured between insulating plates to the upper end of `the trip lever, for example, as by rivets |18. The construction of the .trip lever and its operation is more fully described, and claimed, in the copending application mentioned above.

One leg of a U-shaped iron yoke |8| is secured to the top wall of the interrupter cover 82. as by machine screws |83, as shown. A solenoid coil |82 is mounted between the legs of the yoke |8| for cooperation with a plunger |84 of manetic material, such, for example, as iron cr the like, slidably mounted in the coil and provided with a hollow upper end portion |88, for reception of a coil compression spring |88, the other end oi which is received in a stationary sleeve |90 secured to the upper leg of yoke IBI, and which also acts to guide the upper end of plunger |84 which is telescopically mounted with respect to guide sleeve |80. The outer end of solenoid plunger |84 is reduced in cross section to provide e. stop shoulder |92 for engagement with the lower leg of yoke |8| adjacent aperture |94 therein, and through which extends the reduced lower end of the solenoid plunger. Obviously, coil spring |88 functions to maintain the plunger |84 in its outer position shown in Figs. 5 and 6. Below the yoke 8| the plunger is further reduced in section to form a latch portion |88, which in the normal extended position of the plunger extends into the path of movement of trip lever |10 under .the influence of spring |14.

A bimetal strip 200 has one end thereof secured to flange 3B of cover 32, as by screws |00. and the other end thereof is provided with a transversely extending adjustable latch portion 202, which is adjustable by virtue of being threadedly engaged in an aperture through the free end of the bimetal strip 200. The bimetal strip 200 is constructed in a manner well known in the art, of at least two laminations intimately secured together as by welding or the like, which laminations are of materials having different coeiiicients of expansion. Thus, as shown, the upper lamination of blmetal strip 200 should be of a material having a relatively low coefllcient of expansion, such as steel or the like, and the lower lamination should be of a material having a relatively higher coeiilcient of expansion, such as brass or the like, so that when the strip becomes heated, the outer end thereof will deflect upwardly to bring the latch portion 202 above the path of movement of catch portion on trip lever |01. It will be noted that the latch portions |08 and 202 on the solenoid plunger and bimetal strip, respectively, are relatively offset from each other along the path of movement of i3 catch on'trip lever |10 when moved in a counterclockwise direction bycoil spring |14.

The reason for this will become apparent in the description oi' the operation of this trip mechanism given below.

The electrical circuit through the circuit breaker shown in Figs. and 6 proceeds from terminal socket |02 on cover 32 through cover l2. bimetal strip 200, conductor 204, solenoid coil |02, conductor 200 to contact rod 14, and thence to the lower fixed contact of the breaker and the lower breaker terminal in a manner fully described in the previously mentioned copending application. It can be seen then, that the bimetal strip 200 and solenoid coil '|02 are connected in series in the circuit through the circuit breaker shown in Figs. 5 and 6.

The time delay and lockout means shown in Figs. 5 and 6 and operating mechanism for reclosing the circuit breaker and resetting the same after lockout is identical with that previously described. and hence will not be again described in detail here to avoid repetition.

Uponthe occurrence of an overload in the embodiment of my invention shown in Figs. 5 and 6, solenoid coil |82 is instantly energized and draws plunger |04 upwardly against spring |00, thereby lifting the plunger latch |90 away from catch i 00 on trip lever |10. I'he trip lever will then rotate counterclockwlse under the influence of its spring |14, about pivot |12, until catch |00 strikes latch 202 on the bimetal strip 200. This travel obviously will be very short, and, of course, will not be sufficient to move the contact rod 14 upwardly out of engagement with the fixed contact of the breaker, and the breaker will not be tripped. The overload current also f passing through the bimetal strip 200 causes it t0 gradually heat up, and after a predetermined time, it will deflect upwardly until its latch projection 202 releases the catch |00 on' trip lever |10, to permit the trip lever to rotate to the extreme limit of its travel, thereby raising the contact rod 14 suiilciently to establish an arc in the arc chamber 62, and the pressure of the arc gases will then operate in the manner previously described to move the contact rod 14 upwardly to its limit of travel, and thereby interrupt the circuit. As fully explained in my previously mentioned joint copending application, travel of conin arc chamber 82 causes pivot pin 18 to engage `time delay caused by the dashpot in the same manner as described in connection with the embodiment of my invention shown in Figs. 1 to '4.

As the breaker closes in on a short circuit or an overload which has not cleared, it will be tripped out substantially immediately by solenoid coil |02. The bimetal latch 202 will not prevent this tripping because it is still in a tripped or heated position. This will also be true tor the second or third tripping. if the breaker does not close back in on a normal circuit vafter the second or third reclosure. It, however, the circuit is cleared after the second or third reclosure, the bimetal strip 200 will gradually cool and resume the position shown in Fig. 5. so that at some later time when an overload comes upon the circuit, it will then trip the circuit breaker with thermal time lag characteristics as it did the nrst time.

It can be readily seen from the foregoing that I have provided a device for tripping an automatic reclosing circuit breaker, `which has thermal time lag characteristics upon the nrst operation thereof, and magnetic or instantaneous characteristics upon each succeeding operation unless a considerable time elapses between such operations. The particular structure described above and illustrated in Figs. 5 and 6 is specifically disclosed and claimed in my copending application Serial No. 582,829, on Circuit interrupters, filed March 15, 1945, as a, division of this application,

' cation.

the adjacent edge of trip lever |10 to rotate the same back to the position shown in Fig. 5, and thereby enable it to reset on latch projection 00 of the solenoid plunger which will be projected outwardly by spring |00 as soon as the circuit is interrupted within ar-c chamber 02. This will occur substantially instantaneously after tripping, but at this time the bimetal strip 200 will not have cooled suiliciently to allow its latch projection 202 to move back downwardly into the path of movement of the catch |80. The solenoid plunger |04, however, will reset to the p0- sition shown in Fig. 5 substantially as quickly as the breaker contact rod pivot pin 10 can reset trip lever |10. This resetting action will move the trip lever catch |00 to the right of solenoid latch |00, as seen in Fig. 5, and the trip lever will be latched in this position, although the bimetal is not in a` latching position. After the breakercontact 14 has moved `to the upper limit of its travel and the circuit has been interrupted within the are chamber 02, it is moved downwardly to then reclose the circuit and assigned to the same assignee of this appli- It will be apparent from the foregoing that I have provided a novel type of automatic reclosing circuit breaker which is adapted to automatically reclose a circuit following an interrupting operation a predetermined number of times, and then lock the circuit breaker contacts in an open circuit position. According to my invention, the pressure caused by the arc gases is confined in an arc chamber to open the circuit breaker contacts, and I have disclosed specically two difierent species of tripping means for initially separating the contacts suiliciently to establish an arc in such an arc chamber. My invention also embodies novel time delay means operable on reclosure of the breaker contacts, and operable in response to a predetermined number of successive reclosures to lock the circuit breaker contacts in an open circuit position. By employing a iiuid time delay means for delaying closing 'of the breaker contacts, which uses the circuit breaker arc extinguishing fluid', I am enabled to insure complete flushing of arc chamber 02 irrespective of the viscosityv of the liuid. This is important where a uid such as oil is used which is subject to'changes in viscosity in response to temperature changes which are met in actual service conditions.

It is also apparent that all of the operating parts of my novel breaker are mounted on the container cover 02. This permits ready inspection of the same by merely removing the cover, and obvlates the necessity of securing any parts to the porcelain container 2.

Although the trip mechanisms disclosed, the Y invention in accordance with the patent statutes', I desire that it be understood that my invention is to be interpreted as broadly as possible and not limited to the speciiic embodiments disclosed, inasmuch as it will be obvious, particularly to persons skilled in the art, that many changes and modifications may be made in these particular structures without departing from the broad spirit and scope of my invention. Therefore, I desire that my invention be not limited in any respect except as defined in the following claims, and as required by the prior art.

I claim as my invention:

1. In a circuit interrupter including a substantially closed arc chamber, separable contacts in said chamber at least one of which is slidably mounted in a wall of said chamber, and means for moving the other of said contacts away from said one contact to draw an arc therebetween, whereby the pressure developed by said arc operates to increase said separation by forcing said one contact to slide outwardly with respect to said chamber.

2. In a circuit interrupter including a substantially closed arc chamber, separable contacts in said chamber, at least one of which'is slidably mounted in a wall of said chamber, means for moving the other of said contacts away from said one contact to draw an arc therebetween, whereby the pressure developed by said arc operates to increase said separation by forcing said one contact to slide outwardly with respect to said chamber, and a vent for said chamber controlled by said other contact to close said vent when said other contact is moved to draw an arc, and to open said vent when said contacts are in engagement.

3. In a circuit interrupter including a substantially closed arc chamber, separable contacts in said chamber, at least one of which is slidably mounted in a wall of said chamber, means for moving the other of said contacts away from said one contact to draw an arc therebetween, whereby the pressure developed by said arc operates to increase said separation by forcing said one contact to slide outwardly with respect to said chamber, a vent for said chamber controlled by said other contact to close said vent when said other contact is moved to draw an arc, and to open said vent when said contacts are in engagement, and means controlled by said one contact to vent said chamber when at its outer limit of travel with respect to said chamber, at a point spaced from said first mentioned vent, to provide for flushing of said arc chamber.

4. In a circuit interrupter including a substantially closed arc chamber, separable contacts in said chamber, at least one of which is slidably mounted in a wall of said chamber, means for moving the other of said contacts away from said one contact to draw an arc therebetween, whereby the pressure developed by said arc operates to increase said separation by forcing said one contact to slide outwardly with respect to said chamber, a vent for said chamber controlled by said other contact to close said vent when said other contact is moved to draw an arc, and to open said vent when said contacts are in engagement, and said other contact being movable beyond its arc drawing position to open said vent, and resilientl means opposing said movement, whereby said other contact also operates as a pressure relief means for said arc chamber.

5. In a circuit breaker. a container for an arc extinguishing duid, a chamber adapted to be closed at least during a circuit interrupting operation and at least partially submerged in said fluid, separable contacts in said chamber, at least one oi' which is slidably mounted in a wall of saidv chamber, means for separating said contacts to draw an arc therebetween, whereby the pressure developed by said arc operates to increase said separation by forcing said one contact to slide outwardly with respect to said chamber, means controlled by said contacts in response to a circuit interrupting operation thereof to vent said chamber at a plurality of spaced points, at least one o! which is below the level oi' said fluid and another of which i5 at a different level, whereby said chamber is flushed out and supplied with a fresh quantity of said fluid after each circuit interrupting operation.

6. In an automatic reclosing circuit lnterrupter, separable contacts, at least one of which is movable to open and close said contacts, dashpot means having a pawl and ratchet connection to said movable contact such that a part of said means is advanced a. predetermined amount in response to a movement of said contact in one direction, biasing means for slowly restoring said part to its normal position, and stop means positipned to be engaged by said part to prevent closure of said contacts in responseto advancement of said part an amount greater than said predetermined amount by a predetermined number of successive circuits interrupting operations.

7. In a reclosing circuit interrupter, separable contacts, at least one of which is movable to open and close said contacts, pivoted control lever means connected to said one contact, time delay means having a movable part connected to said lever means by pivoted links which are mutually connected for limited sliding and pivotal movement, and include, respectively, pawl and ratchet elements, one of said link pivots being a frictional pivot, means positioned to engage one of said links in. its position corresponding to the closed position of said contacts for releasing said pawl and ratchet elements, and'said frictional pivot causing engagement of said pawl Vand ratchet elements upon closing movement of said one contact.

8. In a circuit interrupter, a fluid container having an open end, a terminal cap for said end, an interrupting assembly mounted on said cap and including spaced supporting members depending from said cap for supporting an arc chamber at a point spaced from said cap, sep` arable contacts in said chamber one of Vwhich is electrically connected to said cap, at least one of said contacts being movable through a wall of said chamber, and guide means on at least one of said supporting members intermediate said cap and chamber and engaging said movable contact for guiding its circuit opening and closing movements.

9. In an automatic reclosing circuit interrupter, separable contacts, at least one of which is movi able to open and close said contacts, fluid pressure time delay means having a connection to said movable contact such that said means is actuated away from a normal position Vby said movable contact only by movement thereof in a direction to close said contacts, said time delay means being biased to its normal position, and stop means positioned to be engaged by a part movable with said time delay means to prevent closure of said contacts in response to a pre'- determined number of Successive openings thereof, said connection of said time delay means to said movable contact including toggle means ai"t actuated away from a normal position by said movable contact only by movement thereof in a direction to close said contacts, said time delay means being biased to its normal position, means positioned to be engaged by a part movable with said time delay means to prevent 4closure of said Vcontacts in response to a predetermined number of successive openings thereof, said connection of said time delay means to said movable contact including toggle'means arranged to attain substantially its dead center position at the closed position of said contacts, whereby less force is required to close said contacts as they approach their fully closed position, said contacts being biased closed, and current responsive means for effecting opening of said contacts.

11. In a reclosing circuit interrupter, separable contacts, at least one of which is movable to open and close said contacts, fluid pressure time delay means having aK connection to said movable contact such that said means is actuated byv said movable contact away from a normal position only by movement thereof in a direction to close said contacts, said time delay means being biased to its normal position, means positioned to be engaged by a part movable with said u time delay means to preventv closure of said contacts in response to a predetermined number of successive openings thereof, said connection of said time delay means to said movable contact including toggle means arranged to attain substantially its dead center position at the closed position of said contacts, whereby less force is required to close said contacts as they approach their fully closed position, resilient means biasing said contacts closed, current responsive means for effecting opening of said contacts, and said contact closing resilient means also connected to said movable contact by toggle means arranged to approach dead center position in closing said contacts.

12. In a circuit breaker, a container for an arc extinguishing fluid, a substantially closed arc chamber at least partially submerged in said fluid and substantially filled with said fluid, separablecontacts in said chamber at least one of which is slidably mounted in a -wall of said chamber, means responsive to an interrupting operation of said` breaker for .flushing said chamber with said fluid, fluid time delay means at least partially submerged in said container so as to utilize Asaid fluid, and said time delay means associated with said one contact to delay the closing movement thereof.

13. In a circuit breaker, a container for an arc extinguishing fluid, a substantially closed arc chamber adapted to .be at least partially submerged in said fluid, separable contacts in said chamber, at least one of which is slidably mounted in a wall of said chamber, electro-responsive means for moving the other `of said contacts away from said one contact to draw an arc therebetween, whereby the pressure developed by said arc operates to increase said separation by forcing said one contact to.slide outwardly with respect to -said chamber, and means responsive to a predetermined number of successive circuit interrupting operations of said contacts for maintaining said contacts disengaged.

14. In an automatic reclosing circuit interrupter, a fluid container adapted to be substantially filled with an arc extinguishing liquid, separable contacts at least one of which is movable tok open and close said contacts, said contacts positioned Yin a said container below the liquid level thereof to utilize said liquid to extinguish the arc, fluid pressure time delay means having a connection tovsaid movable contact such that said means is actuated by said movable contact at least 4by movement thereof in a direction to close said contacts,` and said time delay means also positioned in said container below the liquid level to utilize said fluid in the operation thereof and operating independently of the complete extent of opening movement of said contacts.

15. In an automatic reclosing circuit interrupter, separable contacts at least one of which is movable into and out of engagement with the other, electro-responsive means for separating.

said contacts to interruptthe circuit, said movable contact being biased towards the other of said contacts to automatically close the circuit after a circuit interrupting operation, time delay means having a connection with said movable contact for at least delaying movement of said one contact into engagement with the other of said contacts, and said connection of said time delay means and movable contact comprising mechanical motion transmitting means the mechanical advantage of which varies during its movement for gradually reducing the delaying effect of said time delay means in response to movement of said one contact toward the other of said contacts, whereby to provide for gradual acceleration of the movement of said one contact in a circuit closing operation.

16. In a reclosing circuit interrupter, separable contacts, at least one of which is movable to open and close said contacts. time delay means having 'a connection to said movable contact such that-said means is actuated by said movable contact at least by movement thereof in a direction to close said contacts, said connection of said time delay means to said movable contact including toggle means arranged to attain substantially its dead center position at the closed position of said contacts, whereby less force is required to close said contacts as they approach their fully closed position. l

17. In an automatic reclosing circuit interrupter, separable contacts, at least one of which is movable to open and close said contacts, time delay'means having a connection toy said movable contact such that said means is actuated by said movable contact at least by movement thereof in a direction to close said contacts, said connection of said time delay means to said movable contact including toggle means arranged to, attain substantially its dead center position at the closed position of said contacts, whereby less force is required to close said contacts as they approach their fully closed position, resilient means Ibiasing said contacts closed, current responsive means for effecting opening of said contacts, and said contact closing resilient means also connected to said movable contact by toggle means arranged to approach dead center position in closing said contacts.

18. In a circuit breaker, a container for an arc extinguishing fluid, a chamber adapted to be closed at least during a circuit interrupting operation. and at least partially submerged in said iluid, separable contacts in said chamber arranged to be forced apart by fluid pressure in said chamber, means for separating said contacts to draw an arc therebetween, whereby the pressure developed by said arc operates to increase said separation, means responsive to a circuit interrupting operation to vent said chamber at a plurality of spaced points, at least one of which is below the level of sai-d lluid and another of which is at a diierent level, whereby said chamber is flushed out and supplied with a fresh quantity of said fluid after each circuit interrupting operation.

19. In a circuit breaker, a container for an arc extinguishing iluid, a substantially closed arc chamber at least partially submerged in said duid and substantially filled with said fluid, separable contacts in said chamber, electro-responsive means for separating said contacts, said contacts being biased into engagement to automatically close the circuit in response to a circuit interrupting operation, means responsive to an interrupting operation of said breaker for flushing said chamber with said iluid, fluid time delay means at least partially submerged in said container so as to utilize said iluid, and said time delay means associated with one of said contacts to delay the closing movement thereof.

20. In an automatic reclosing circuit breaker, a container for an arc extinguishing liquid, separable contacts positioned in said container so as to be submerged in said liquid for extinguishing the arc formed when said contacts separate, electro-responsive means for causing separation of said contacts to interrupt the circuit, said contacts being biased closed in response to a circuit interrupting operation to automatically reclose the circuit, and fluid time delay means positioned in said container below the liquid level so as to utilize said arc extinguishing liquid for delaying closing movement, of said contacts and operating independently of the complete extent of opening movement of said contacts.

` 21. In a circuit breaker, a container for an arc extinguishing iluid, a chamber adapted to be closed at least during a circuit interrupting operation and at least partially submerged in said fluid, separable contacts in said chamber arranged to be forced apart by fluid pressure in said chamber, means for separating said contacts w to draw an arc therebetween, whereby the pressure developed by said arc operates to increase said separation, means biasing said contacts into engagement, fluid time delay means in said container and utilizing said fluid to delay movement REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 508,652 'I'homson Nov. 14, 1893 732,851 AHanchett July 7, 1903 835,493 Baldwin Nov. 13,' 1906 913,320 Sulser Feb. 23, 1909 1,116,504 Simon Nov. 10, 1914 1,157,960 vPost Oct. 26, 1915 1,201,491 Neahr Oct. 17, i916 1,394,087 Heinrich Oct. 18, 1921 1.402.310 Nicholson Jan. 3, 1922 1,530,444 Trencham Mar. 17, 1925 1,650,172 Ainsworth Nov. 22, 1927 1,922,862 Prince Aug. 15, 1933 1,969,575 Nordhem Aug. 7, 1934 1,983,068 Cardone Dec. 4, 1934 2.049,328 Skeats July 28, 193B 2,069,082 Walle Jan. 26, 1937 2,078,657 Gamel et al Apr. 27, 1937 2,138,323 Hilliard Nov. 29, 1938 2,148,472 Joy Feb. 28, 1939 2,163,558 MacNeil June 20, 1939 2,275,885 Bartlett Mar. l0, 1942 2,318,421 Rawlins et ai May 4, 1943 FOREIGN PATENTS Number Country Date 147,456 Great Britain Apr. 28, 1921 645,130 France June 26, 1928

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