US2622167A - Circuit interrupter - Google Patents

Description

De@ 16, 1952 H. l.. RAwLlNs ETAL 2,622,167

CIRCUIT INTERRUPTER BY G l ATToRN Y Patented Dec. 16, 1952 CIRCUIT INTEBRUPTER Herbert L. Rawlins, Pittsburgh, and James M. Wallace, East McKeesport, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 31, 1946, Serial No. 719,572

` (Cl. Zim- 89) 17 Claims.

This invention relates in general to electric circuit interrupting devices, and more particularly to automatic reclosing circuit'breakers.

In automatic reclosing circuit breakers oi the type'having contacts which are' opened electrically in response to overloads Yon the circuit `and are biased to automatically reclose when the circuit is opened, one problem encountered is that of obtaining adequate contact pressure when the breakage is closed and at the same time obtaining full contact separation regardless of the current value of the overload. In accordance with an important aspect of this invention, this problem is solved by providing a contact pressure spring which is effective only when the breaker contacts are closed and for a very short travel of the movable contact adjacent its closed circuit position, so that the movable contact is free after a very small amount of opening movement to be moved to its full open circuit position. e

Accordingly, one general object of this invention is to provide in a circuit breaker of the type which automatically recloses due to a closing bias on its contacts, novel means for obtaining adequate contact pressure at the closed circuit position without interfering with circuit opening movement of the device to a full open circuit position irrespective oi the current value oi the overload causing the circuit opening operation.

Another object oi this invention is to provide a circuit breaker having electro-responsive means to cause separation of its contacts and a closing bias to automatically reclose the circuit, with novel means for applying additional closing pressure on the contacts solely at and closely adjacent to closed circuit position. i

A more specic object of this invention is to provide for a device of the type described, a novel contact pressure toggle spring structure arranged to move from an oit-center position when the contacts are closed and substantially closed where contact pressure is exerted on the contacts, to a substantially on-cen'ter position during contact travel into and out of engagement wherein substantially no force is exerted on the contacts.

Another object of 'this invention is to provide in an automatic reclosing circuit breaker having means to hold the breaker contacts open in response to the occurrence of a predetermined number Vof closely successive circuit interrupting operations' of the breaker, novel contact pressure 'means which is maintained ineiective when said contacthoiding means is operative.

Another general object of this invention isto provide a' novel automatic reclosing circuit breaker construction which. is Iefficient and reliable in operation, and yet may be economically produced.

Anotherl object of this invention is to provide in a device of the type described wherein a solenoidv is employed for separating the circuit breaker contacts and has lost motion relative to rembodiments thereof, when taken in connection with the attached drawings, in which:

Figure l is a substantially central vertical section View of a circuit breaker constructed in accordance with this invention;

Fig. 2 is a transverse section of the breaker shown in Fig. l taken substantially on the line II-II of Fig. 1;

Fig. 3 is a partial vertical section view of the upper end ofthe breaker shown in Fig. 1,'taken substantially on the line III-'III of Fig. 2; and

Fig. 4 is an enlarged partial 'section view of the upper end of the breaker shown in Fig. l, taken substantially on the line IV-IV of Fig. 2.

The breaker show n on the drawings is illustrated as being mounted in a metal tank 2 hav- 'ing a yclosed bottom` wall and an open top. Preferably, the tank is adapted to be lined at least over the bottom wall and up to a point adjacent the openl top of the container with a liner 3 of insulating'material such as ber, or the like, and is lled up to the level L with liquid, preferably a liquid having arc extinguishing ability such as oil. The upper end of tank 2 is provided with an outwardly extending ilange 4 on which the fiange 8 of a cover casting 6 is adapted toA be seated, preferably, with a gasket H3 interposed therebetween. Flange B 'ofcover casting 5 may be provided with van integral lip'lZ, and the cover may besecured to the tank ,in any desired manner, suchfor example, as by bolts (not shown) vextendingv through openings I4 in cover iiange 8* and secured to suitably formed brackets on the tank.

The breaker contacts and certain of the contact actuating mechanism are adapted to be supported in tank 2 from cover casting t by means of a pair of integral supporting lugs i6 depending from the top wall of` the cover casting and adapted to engage insulating spacer rods i8 having threaded studs (not shown) engaging threaded openings in rods I3 and lugs i6 on supporting casting 2li. A supporting plate 2.2 may be supported in a similar manner from casting 20, so that a solenoid coil 24 may be mounted between casting 26 and supporting plate 22, with the central opening in the coil aligned with openings provided incasting 26 and plate 22.

Spaced stationary contacts 26 of the breaker are each supported from plate 22 by a support 28 of insulating material, such as ber, formed of U-shape, with the stationary contacts being mounted in openings provided in the base portions 30 of each support 28, and with the upper ends of each support 28 havingV laterally extending flanges 32 by means of which each support is secured to supporting plate 22. As illustrated, each contact 26 is formed as the head ofV a bolt to which a conductor may be secured, as by the nuts 34. 1

Stationary contacts 26 are adapted to be closed by engagement therewith of a bridging contact 36 having contact tips 38 at opposite ends thereof for engagement with the stationary contacts, respectively. Bridging contact 36 is supported substantially centrally thereof on a slidable contact actuating rod 44 by pivot pin 46 for limited Ypivotal movement about a transverse axis on contact actuating rod 44. Contact rod 44 being mounted for longitudinal sliding movement through coil 24 and the aligned openings in plate 22 and casting 20, it will be observed that bridging contact 36 is free to adjust itself to the stationary contacts by restricted pivotal movement about its pivot mounting 40. Contact rod 44 should be of an insulating material such as ber or a molded insulating material.

A 'Ihe upper end of contact actuating rod 44 has a pair ofconnecting links 46 positioned at each side thereof and pivoted thereon as by a pivot pin 48,'with the upper ends of these connecting linksemounted on a' common pivot pin 5!) for a pair of toggle levers 52 and 54. Toggle levers 52 an`d`54-are bothformed of sheet material, with lever 54 being bent to substantially channel form withoutwardly extending flanges y56y adapted to be received at the free ends thereof in recesses 56 provided in the spaced downwardly depending fingers of an angled supporting bracket 60 which, in turn, is secured as by screws 64 to lugs 62 integral with the cover casting. 'Preferably the base ofthe channel part of-toggle lever 54 is extended at 66 through the space between the supporting ngers of-bracket 60, and at the other end of Vlever 54 the sides of the channel formation thereof are extended to be mounted on pivot pin 50. A coil tension spring 6B has one end hooked into an opening lll provided in toggle lever 52, `and has the opposite end thereof hooked over an integral spring support 12 on the cover casting.

It will be observed that in the closed circuit position of the breakervillustrated on the drawings in full lines, the line of action of toggle spring 68 is below the pivot supporting recesses 58for toggle lever 54. and accordingly, the toggle spring acts to bias bridging contact 36 into engagement with stationary contactsy 26 of the breaker, under a predetermined pressure. However, as soon as contact operating rod 44 moves upwardly to separate the bridging contact from the fixed contacts of the breaker, toggle lever 54 will pivot about recesses 53 and the line of action of toggle spring 68 will thus be caused to approach that pivot point so that in response to a very small Ycontact separation the line of action yof toggle spring 68will pass through pivot recesses 58 which is the on-center position of the resilient toggle arrangement comprising toggle levers 52 and 54 and toggle spring 68. As a practical matter, the opening movement of the contacts necessary to move toggle levers 52 and 54 to the oncenter position mentioned above may be made very small, in one operative device being on the order of one-quarter of `an inch. When toggle levers 52 and 54 reach their on-center position referred to above, further relative movement of the twotoggle levers in the same direction is prevented because the upper edge of toggle lever 52 engages iitherbasebfthe central channel formation of toggle lever 54. Moreover, since the point at which toggle spring 58 is hooked into opening Hl of lever 52 then substantially coincides with recesses 5B in which toggle lever 54 pivots during contact opening movement, it will be apparent that the remainder major part of contact opening movement will occur substantially uninfluenced byv toggle 68. Substantially the reverse of the above operation occurs when contact ,operating rod-44 moves downwardly to closethe circuit from the full open contact position, because during the first and major part ofy contact closing movement, levers 52 and `54 will be in engagement so that such movement will be uninfluenced by toggle spring 68. However, as soon as pivot 53 passes below a line drawn from the remote end of toggle spring 68 throughpivot recesses 58 for link 54, toggle spring 68 will then be effective to move the toggle levers toward the full line position shown in Figs. 1 and 3, and the force exerted by toggle spring 68 then tending to close the contacts will continue to increase as toggle levers 52 and 54 move further away from their oncenter positions. While it is preferred when toggle levers 52 and 54 are in engagement that these levers be engaged as closely as possible to their on-center position, so that toggle spring 68 is ineffective to bias the contacts in either direction, rather than risking that the engagement occur at a position slightly overcenter from that shown in Figs. 2 and 3, itmay be desirable to make the engagement occur just prior to attainment by levers 52 and 54 of their ori-center position. When this is clone, toggle spring 68 will exert some slight bias tending to close the contacts, and this may be desirable in some cases. It will be noted that toggle lever 52 is provided with an integral hook 13 for limiting its separation from toggle lever 54. Solenoid coil Z4 previously mentioned i adapted to be energized under certain conditions for automatically opening the circuit breaker contacts. The central opening through coil 24 preferably is provided with a cylindrical sleeve 74 in which a solenoid core I6 is adapted to be slidably mounted in a piston-like manner. Core 16 is in the form of a cylindrical sleeve having opposed slots 'i8 in the upper portions thereof adapted in the normal closed circuit position of the device illustrated in Fig. l to extend partly above and partly below supporting plate 22, by engagement of an exterior shoulder adjacent the upper end of the core with a sleeve 6!) which has an external rib held between the sleeve 14 for the coil and supporting plate 22. The lower end `of core 'l5 is also provided with opposed openings l, for a purpose to be hereinafter described. .A contact actuating sleeve 82 is telescoped over contact actuating rod 44 and its lower end is received in core T6 and preferably threadably mounted therein. A coil compression spring 8E is provided` within actuating sleeve 82 on contact actuating rod 44 and is adapted to react'between a shoulder in the. 'core and ai pin't extending -transversely through actuating rod 44.

The circuit through the circuit breaker thus far described may now be traced from the point where it enters tank 2 through one of a pair of vterminal bushings S0 (only one being shown), with each bushing secured to cover castings 6 as by bolts .S2-fl, and each being provided -with a terminal fixture 92 at thev upper end thereof mounted on a conductor element which extends through the bushing and emerges from a reduced extension 9S of the bushing seated in an opening provided in the top wall of cover casting S, and

lproceeds by conductor Sii directly to one xed contact 2li ofthe breaker. When the contacts v`are -in engagement, the circuit then proceeds 'through bridging Contact 30y to the other xed .contact it, and then by way oi a conductor |09 to one terminal of solenoid coil 24. The other terminal of coil 2li is adapted to be connected by a conductor |02 to the conducting means in the other terminal bushing 90. It will be apparent that solenoid coil 24 in this embodiment of the invention is connected in series in the circuit through the circuit, breaker so as to be venergized at all times when the circuit breaker -is closed, an amount dependent upon the value -of current flowing in the circuit.

For any given rating ofhcircuit breaker, soleincid coil 24 is designed to become sufhciently yenergized when the load current in the circuit exceeds its rating as to attract core lli and move the relatively small clearances between the core and sleeves 'Fil and iii and between sleeve 02 and casting 253. Accordingly, opening movement of the core will be slowed up by the aforesaiddashpot action4 an amount determined by the current value of the overload, therefore, an inverse timeecurrcnt clia-racteristicV on opening is obtained. Finally, when openings 8i clear the upper edge of sleeve liti, core ifi will no longer be restrained by the dashpot action, and'nal opening movement thereof may be relatively rapid. When core "i commences its upward travel, bridging contact 3? being held engaged by toggle spring t3 does not move, so that spring 85 is compressed until the energy stored in spring 85 is'suilcient to overcome the force exertedv by Atoggle spring Sli, at which time contact actuating yrod 44 will start to move upwardly. As soon as actuating rod iii moves upwardly, the force exerted by toggle spring 51 begins to decrease and in a veryrshort distance has substantially no value at all, so that the remaining major part of the circuit opening movement or bridging Contact occurs extremely rapidly due to expansion of spring 85.

In order to store as much energy as possible in spring et during a circuit opening operation, it will 'ce noted that this spring is of a special type being wound on two di'lerent pitches, with the upper coils of the spring as viewed in 1 having a relatively large pitch compared to the pitch of the lower coils or spring 8b. Spring 85 may be formed of a single piece of wire which is uniform in diameter, but by making the coils of different pitches, it will' be apparent that the force-distance characteristic of such a spring can be made tol closelyapproximate the forcedistance characteristic of solenoid coil 24 and its core 16. The reason for this is that an ordinary spring having -a uniform pitch has a lstraight line force-distance characteristic which obviously cannot be matched with the forceldistance characteristic of a solenoid. A By provid- `ing a spring having a'number of coil portions .differing in pitch, when the-coils of small pitch go solid, the deection of the remaining coils will be increased accordingly so that instead of a straight line forcedistance characteristic the resulting characteristic of the spring as a whole, will comprise a series of straight lines at progressively increasing angles, and these obviously can be made to closely followthe characteristic curve of .any particular solenoid. Accordingly, it will be apparent that the maximum energy available from the solenoid coil 24 will be stored in. compression spring BE and will thus be available to 4overcome the closing bia-sl of toggle spring 68,

preferably at some point during initial movement of core 'It before actuating sleeve 82 engages ange 89 on actuating rod lill. However, flange 89 is provided to obtain a positive contact separation in the event there is any sticking or welding of the bridging contact to stationary contacts 26.- In either case, it is apparent that toggle levers 52 and 54 willfbe moved to their `ori-center position in the manner previously described, and bridging contact -36 will be moved by spring St' to its full open circuit position.

When the breaker contacts have attained their full open circuit position, the parts associated therewith are biased to return by gravity, and as previously pointed out, they may also be biased by toggle spring 68 if it is desiredto stop relative movement of toggle levers 52 and 54 just short of attaining their on-center position during opening of the contacts. In either case, the closing bias is relatively light and Will be opposed by .the dashpot action of core 1B when it has moved downwardly a distance sufficient to bring openings 8| below sleeve 80. Accordingly, the return movement will be relatively slow until pivot point 50 moves below a line extending through pivot recesses 58 and the fixed endof spring 68 at bracket 12, whereupon bridging contact will be rrapidly moved'to eilect a snap-action closing of the breaker contacts by toggle spring B8. .Moreoven at about this same time the lower -ends of slots 78 in core 16 will clear the lower 4edge of sleeve 80 so as to vent the dashpot come prising sleeve '|4and core '16.

In order to limit the number of operations of the circuit breaker in close succession upon the occurrence of a continuing overload on the cir- -cuit and to provide for manual operation, means are provided for holding the breaker contacts open in response to the occurrence of a predetermined number of closely succeeding circuit interrupting operations, `which means can be manually actuated. This means comprises a toggle lever |04 pivoted at one end as at |06 on a U- shaped spring lever |08 which, in turn is pivotally supported as at |0 between the legs of a U-shaped supporting bracket secured to cover casting 6. The other end of toggle lever |04 is pivoted, as by a pivot pin I2, to the adjacent end of a second toggle lever ||4, and this,

in turn, is mounted on a pivot pin ||6 interl Vcover casting 6. A slot |20 is provided through Vtacts into engagement rapidly.

'the'cover casting 6 forreceiving the other end of toggle lever H4 which acts as a manual operating handle at the exterior of the circuit breaker casing, being provided with an angled hook end |22. A coil compression spring |24 is mounted to react between the bight of lever |08 and cover casting 6. Normally, toggle levers 04 and H4 are held by spring |24 with pivot H2 below the center line connecting pins |06 and H6, with the outer end of lever H4 positioned in and beneath an integral hood |26 on cover casting 6, in engagement with an adjustable stop screw |28 mounted in the hood.

In the position of toggle levers |04 and H4 illustrated, they have no effect on operation of the circuit breaker as previously described, being normally inactive in this respect. However, lever |08 has a connecting pin H3 extending beneath toggle levers 52 and 54. Accordingly, if it is desired to manually open the circuit breaker contacts, a hook stick or similar operating member may be engaged with the upper side of angle hook |22 of toggle lever H4 and pulled downwardly to rotate the toggle lever in a counterclockwise direction about its supporting pivot I I6 to move toggle levers |04 and H4 overcenter in an upward direction, and in doing this, pin H3 engages toggle levers 52 and 54 and moves them upwardly in a counterclockwise direction, thus carrying contact actuating rod 44 upwardly to separate bridging contact 36 from stationary contacts 26. The contacts will be held open by spring |24 which maintains toggle levers |04 and H4 in their upper overcenter position. In thus manually opening the circuit after toggle spring 68 is moved to its on-center position, it will be observed that the spring |24 is only required to maintain the contacts of the breaker open against the relatively light closing bias due 'to gravity, and such light bias as may be due to toggle spring 68 'in the event that toggle levers `52 and 54 are stopped just prior to reaching their on-center position. With the breaker contacts maintained at their open circuit position following the manual circuit opening operation described above, it will be apparent that the outer end of toggle lever H4 projects below hood |26 of cover casting 6 so as to provide a readily visible indication that the breaker contacts are maintained at open circuit position. It will further be apparent that the breaker contacts may then be closed only by manual operation of tog- Vgle lever H4 in the opposite direction, that is, by

exerting an upward force on the outer end of the toggle lever by engagement of a hook stick or' the like with the underside of hook |22, to rotate lever H4 in a clockwise direction to move it and toggle lever |04 back overcenter to the position illustrated on the drawings. This manual operation of toggle lever |4 does not directly close the breaker contacts but merely permits closure of the contacts in the manner previously described, that is, initial closing movement of the contacts being due to the bias of gravity and possibly some slight bias due to toggle spring 68,

until bridging contact 36 is closely adjacent stationary contacts 26 when toggle spring 68 is moved below its on-center position and suddenly becomes effective to iinally move the con- It will be observed that on manual opening of the circuit', the full force of spring |24 becomes eiective to open the contacts as soon aslevers |04 and H4 move overcenter, and actual opening of the contacts by spring., |24 is independent of the operating y8 hook stick. Similarly in manually resettingtoggle levers |04 and H4 there is no possibility that withdrawal of the hook stick after resetting can disturb the position of the toggle levers because in resetting the hook stick engages only a lowe edge surface of hook |22.

An integrating mechanism for automatically moving toggle levers |04 and H4 upwardly overcenter and thus preventing reclosure of the circuit breaker in response to a predetermined number of closely successive circuit interrupting operations is provided comprising a cylindrical tube |30 clamped or otherwise secured in a lateral extension of casting 20 at the top of solenoid coil '24, and this tube has a plug |32 threaded into the lower end thereof with the plug having la, small central opening controlled by a ball-check valve |34, which permits ilow of uid into the lower end of tube |30 but prevents out-flow. An integrating piston |36 is mounted in tube |30 and normally rests on the upper end of plug |32, being provided with a reduced extension |38 at the upper end thereof having a plurality of spaced circular fianges |40 forming rack teeth thereon, and having an elongated extension |42 of insulating material on the extreme outer end thereof which is positioned below an extension |43 on toggle lever V| 04. A pawl lever |44 is pivotally mounted at yone end as at |46, this end of pawl lever |44 Ibeing split with legs loc-ated at each side of tube |30 and with pivot |46 supported on spaced supporting flanges |40 integral with casting 20. Pawl lever |44 has a connecting web intermediate its ends, and at the other end thereof the sides of the lever are extended outwardly and laterally as at I 48, to normally be in engagement with a washer |50 mounted Von actuating tube 82 in engagement with a shoulder adjacent the outer end of this tube. Pawl lever |44 is normally biased into engagement with washer |50 by a coil tension spring |52 hooked over the remote edge of the web of the pawl lever at one end. and anchored to an ear integral with casting 20 at its other end. Pawl lever |44 is provided with a pawl member |54 pivoted thereon as at |56, and biased by a spring |58 in a counterclockwise direction to a position wherein a portion of pawl member |54 engages the connecting web of pawl lever 44.

When the circuit breaker operates to open the circuit, washer |50 will be car-ried upwardly with actuating sleeve 82 and thus carry the free end of pawl lever |44 upwardly with it to move pawl member |54 into enga-gement with the upper one vof flanges |48 on integrating piston |36 to thus carry the piston upwardly a predetermined distance. When the breaker recloses following such a iirst circuit interrupting operation, integrating piston |36 is left at the position to which it was advanced since pawl member |54 is free to disengage circular flanges |40, `and if the breaker remains closed, integrator piston |36 will slowly reset to the position shown in Fig. l due to leakage of liquid in cylinder 30 below piston |36 through the relatively small clearance between the cylinder and pist-on. However, if the breaker immediately reopens after a rst opening and reclosing operation, pawl member 54 this time will engage the next lower circular flange |40 on the integrator piston and raise the piston a further amount. Subsequent reclosing will result then in leaving piston |36 'at this furtherA advanced position from which it eventually will reset if the breaker remains closed. However, in the event of a continuing overload, the 'breaker levers |04-and -|I4 will beautomatically moved upwardly overcenter to maintain-the breaker contacts separated onlyfin response to a predetermined number of Aclosely successive -circuitv opening and closing operations, usually four suchf operations, however, in the event a lesser number f of closely successive opening and closing operations occurs, the integrating mechanism will reset and the breaker contacts will be automatically held open only when the aforesaid predetermined number of opening and closing operations occurs in close succession.VVV Obviously, after the breaker contacts have been automatically :actuated to a position where they are held open by toggle spring |24, they can be reclosed only by `manual operation of toggle lever I I4 in the manner previously described. L Y l Y If desired, a counter |60 for registering the number of operations of the breaker may beinstalled in cover casting `6 adjacent hood portion |26, and an opening |62 provided through the cover casting to render the counter register-visible from the exterior. The actuating arm of counter |60 is preferably connected by a link |'64 pivoted at |65 with the adjacent end Iof toggle link 52, and it will be apparent that the counter will be `operated each time the circuit breaker opens and closes the circuit.

Similarly, a protective gap device |66 preferably of the yexpulsion type may be provided to prevent operation of the breaker on voltage surges, with the `outer tube `of the arrester mounted intermediate its ends on an extension |68 of supporting plate 22' at the underside of solenoid coil 24, being secured thereto as by nuts |10 threaded Von thearrester tube. One terminal |12 of theA arrester may be connected with conductor |00 and one terminal of solenoid Icoil V24, with the other terminal of the arrester (not shown) connected with the other terminal of coil 24 and conductor |02.` This arrester and its particular manner of -mounting and connection with this type Vof apparatus is more particularly disclosed and claimed in our copending application Serial No. 694,074 anvOvervoltage `Protective Devices, led August 30, v1946, now Patent No. 2,550,124, April 24, 1951, an-d assigned to the same assignee of this invention. I As stated above, the purpose of providing an arrester |66 connected in thel manner described herein and in the aforesaid copending applicationl is to provide a by-pass to protect solenoid coil 24 on voltage surges such, for example, as those due to lightning strokes, 'which are not overloads on the circuit and, consequently, it is not desired that the breaker open on such surges. Y

From the foregoing, it is believed apparent that the structure disclosed herein provides in an automatic reclosing circuit breaker of the type having electrical means for causing opening of the breaker contacts and having the contactsbiased toautomatically reclose when the circuit is opened, a contact pressure spring effective to additionally bias the breaker contacts into engagement, butl which bias is substantially entirely destroyed as soon as the contacts separate a very short distance, so that the breaker contacts are substan- 7'5therefor comprising .the invention of J M. Wale a spring whose force-distance characteristic closely matches that of the solenoid opening means and eventually overcomes the bias of the contact pressure spring', or-else the lost motion becomes fullyy taken up so that thecontacts are always rapidly separatedand moved thefp'r'edetermined short distance 'necessary to render the contactlpressure spring inoperative, whereupon the lost motion spring becomes effective to rapidly move the breaker contacts to their fulll open circuit position. It is apparent that toggle spring 68, while providing adequate contact pressure for the particular form of contacts illustrated herein, is also important where contacts other than the butt type contacts illustrated are employed, in order to obtain an extremely rapid nal closing movement of the contacts, because in closing the circuit while the initial and major part of the closing movement of the breaker contactsis used to obtain a time delay, toggle spring 68-nally becomes effective closely adjacent the end of closing movement to suddenly exert its bias on the Contact to rapidly close-the contacts substantially with a snap action, andthis function is important Whether or not the contact pressure function inherent in this structure is used.

With the particular toggle spring arrangement 63 disclosed herein wherein itis effective to bias the breaker contacts only when they are at or closely adjacent their closed circuit position, it is apparent that the only other bias needed to automatically close the breaker contacts may vbe merely that exerted by gravity which is extremely light, so as to offer negligible opposition to opening movement of the breaker contacts to their fully opened position. This also has the advantage of simplifying design of the means for obtaining time delay on closing, since the delaying means is subjected only to this relatively light closing bias. f Y

The structure herein described results in obtaining a. full opening stroke of the breaker contacts on every circuit opening operation `at ay rapid rate, regardless of the current value of the overload causing such operation, Thus, -any overload however small which is capable of moving solenoid core |6- upwardly an amount to com- 1 press spring suiliciently to overcome the bias of toggle spring 63 will open the contacts at least the amount necessary to render toggle spring 68 ineffective to the extent that spring 86 is able to move the bridging contact 36 to its full open circuit position. Furthermore, although but a light closing bias is exerted on the breaker contacts'rl through the major portion of their closing movei ment, they are rapidly moved into final engagement by a relatively heavy bias which may be4 also employed to provide adequate contact pressure when butt type contacts are employed.

Our invention comprises the novel toggle actuating and lockout mechanism and the novel lostmotion spring arrangement for opening the contacts, taken both separately `and collectively,4

whereas, certain otherfeatures disclosed herein are not not our invention; the particular integrator structure including the pawl actuating means lace, A. W. Edwards and J. Kraft being disclosed and claimed in their copending application Serial No. 719,524, led December 31, 1946, on Circuit Interrupters and the particular contact structure and means for extinguishing the arc drawn upon separation of the contacts is the invention of J. M. Wallace and J. Kraft being disclosed and claimed in their copending application Serial No. 718,942, led December 28, 1946, now Patent No. 2,575,738, November 20, 1951, on Arc Extinguishing Structures.

Having described a preferred embodiment oi the invention in accordance with the patent statutes, it is desired that this invention be not limited to this particular construction inasmuch as it will be apparent, particularly to persons skilled in this art, that many modications and changes may be made in this particular structure Without departing from the broad spirit and scope of this invention.

We claim as our invention:

1. In a circuit interrupter, separable contacts, at least one of which is mounted for movement into and out of engagement with the others resilient means reacting between said movable contact and a stationary support for biasing said contacts together to effect at least rapid nal closing movement of said contacts and to exert pressure on said contacts when they are in engagement, electro-responsive means for causing separation of said contacts in response to a predetermined condition of a circuit, and means connected to said movable contact and said resilient means so as to be responsive to a predetermined small initial part of the separating movement of said movable contact for rendering said resilient means inoperative to exert any substantial force on said movable contact, whereby the remaining contact separating movement is substantially uniniluenced by said resilient means.

2. In a circuit interrupter, separable contacts, at least one of which is mounted for movement into and out of engagement with the others resilient means reacting between said movable contact and a stationary support for biasing said contacts together to effect at least rapid nal closing movement of said contacts and to exert pressure on said contacts when they are in engagement, electro-responsive means for causing separation of said contacts in response to a predetermined condition of a circuit, means connected to said movable contact and said resilient means so as to be responsive to a predetermined small initial part of the separating movement of said movable contact for rendering said resilient means inoperative to exert any substantial force on said movable contact, whereby the remaining contact separating movement is substantially uninfluenced by said resilient means, and said last mentioned means also being actuated by said movable contact in its closing movement so as -to be responsive to contact closing movement substantially to the point in opening movement where said resilient means was rendered inoperative for rendering said resilient means operative to rapidly close said contacts and to exert a predetermined contact pressure when said contacts are in engagement.

3. In an automatic reclosing circuit interrupter, separable contacts, electro-responsive means for causing separation of said contacts in response to a predetermined condition of a circuit, said contacts being biased into engagement to automatically close the circuit in response to a circuit opening operation, resilient means add-` tionally biasing said contacts together in the same direction as said reclosing bias to effect at least rapid final closing movement of said contacts and to exert pressure on said contacts when they are in engagement so that contact pressure is the sum of the forces exerted by said reclosing bias and said resilient means, and means connected to said contacts and said resilient means so as to be responsive to a predetermined small initial part of the separating movement of said contacts for rendering said resilient means noperative to exert any substantial force on said contacts, whereby the remaining contact separating movement is substantially uninfluenced by said resilient means. 1 Y

4. In an automatic reclosing circuit interrupter, separable contacts, electro-responsive means for causing separation of said contacts in response to a predetermined condition of a circuit, said contacts being biased into engagement to automatically close the circuit in response to a circuit opening operation, resilient means additionally biasing said contacts together in the same direction as said reclosing bias to effect at least rapid final closing movement of said contacts and to exert pressure on said contacts when they are in engagement so that contact pressure is the sum of the forces exerted by said `reclosing bias and said resilient means, means connected to said contacts and said resilient means so as to be responsive to a predetermined small initial part of the separating movement of said contacts for rendering said resilient means inoperative to exert any substantial force on said contacts, whereby the remaining contact separating movement is substantially uninfluenced by said resilient means, and said lastmentioned means also being actuated in accordance with contact-closing movement so as to be responsive to contact closing movement substantially to the point in opening movement where said resilient means was rendered inoperative for rendering said resilient means operative to rapidly close said contacts and to exert a predetermined contact pressure when said contacts are in engagement.

5. In a circuit interrupter, separable contacts, at least one of which is mounted for movement into and out of engagement with the others resilient means reacting between said movable contact and a stationary support for biasing said contacts together at least when they are in engagement, electro-responsive means having lost motion relative to said movable contact for causing separation of said contacts in responsetol a predetermined condition of a circuit, spring means stressed to exert a force tending to separate said contacts during circuit opening movement of said electro-responsive means relative to said movable contact, and means connected to said movable contact and said resilient means "so as to be responsive to a predetermined small initial part of the separating movement of said contacts for rendering said resilient means inoperative to exert any substantial force' on said contacts, whereby the remaining contact `separating movement is effected by said spring means and is substantially uninfluenced by said resilient means.

6. In an automatic reclosing circuit interrupter, separable contacts, electro-responsive means having lost motion relative to said contacts for causing separation of said contacts in response to a predetermined condition oifa circuit, said contacts being biased into engagement to automatically close the circuit in response to a circuit opening operation, spring means adapted to be stressed during movement of said electroresponsive means relative to said contacts to exert a force tending to separate said contacts which is considerably greater than that of said bias, resilient means additionally biasing said contacts together in the same direction as said reclosing bias at least when they are in engagement so that contact pressure is the sum of `the forces exerted by said reclosing bias and said resilient means, and means `connected to said contacts and said resilient means so as to be responsive to a predetermined small initial part of the separating movement of said contacts for rendering said resilient means inoperative to exert any substantial force on said contacts' whereby the remaining contact separating movement is effected by said spring means substantially uninfluenced by said resilient means.

'7. In an automatic reclosing circuit interrupter, separable contacts, electro-responsive means for causing separation of said contacts in response to a predetermined condition of a circuit, said contacts being biased into engagement to automatically close the circuit in response to a circuit opening operation, overcenter spring means additionally biasing said contacts together in the same direction as said reclosing bias at least when they are in engagement so that contact pressure is the sum of the forces exerted by said reclosing bias and said resilient means, said overcenter spring means being moved substantially to its on-center position in response to a predetermined small initial part of the separating movement of said contacts, and stop means preventing further movement of said overcenter spring in the same direction for rendering said overcenter spring means inoperative to exert any substantial force on said contacts, whereby the remaining contact separating movement is substantially uninuenced by said resilient means.

8. In a circuit interrupter, separable contacts, at least one of which is mounted for movement into and out of engagement with the others overcenter spring means connected between a stationary support and said movable contact for biasing said contacts together at least when they are in engagement, electro-responsive means for causing separation of said contacts in response to a predetermined condition of a circuit, said overcenter spring means being moved in response to a predetermined small initial part of the contact separating movement of said movable contact substantially to its on-center position, and stop means preventing movement of said overcenter spring means overcenter, whereby the remaining contact separating movement is substantially uninluenced by said overcenter spring means.

9. In a circuit interrupter, separable contacts, at least one of which is mounted for movement into and out of engagement with the others overcenter spring means connected between a stationary support and said movable contact for biasing said contacts together at least when they are in engagement, electro-responsive means for causing separation of said contacts in response to a predetermined condition of a circuit, said overcenter spring means being moved in response to a predetermined small initial part of the contact separating movement of said movable contact substantially to its on-center position, stop means preventing movement of said overcenter spring means overcenter, whereby, the remaining contact separating movement is substantially uninfluenced bysaid overcenter spring means, and said overcenter spring means also being moved by said movable contact during its closing movement to become suddenly effective to close said contacts withk a snap action only over said small p-art of contact movement just prior to nal engagement of said contacts.

l0, In an automatic reclosing circuit interrupter, separable contacts, at least one of which is mounted for movement into and out of engagement with the others electro-responsive means for causing separation ofk said contacts in response to a predetermined condition of a circuit, said movable contact being biased into engagement to automatically close the circuit in response to a circuit opening operation, overcenter spring means connected between a stationary support and said movable contact for additionally biasing said contacts together at least when they are in engagement, said overcenter spring means being moved in response to a predetermined small initial part of the contact separating movement of said movable contact substantially to its on-center position, stop means preventing movement of said overcenter spring means overcenter, whereby the remaining contact separating movement is substantially uninuenced by said overcenter spring means, and said overcenter spring means also being moved by said movable contact during its closing movement to become suddenly effective to close said contacts with a snap action only over said small part of contact movement just prior to nal engagement of said contacts.

ll. In an automatic reclosing circuit interrupter, separable contacts at least one of which is mounted for movement into and out of engagement with the others, electro-responsive means for causing separation of said contacts in response to a predetermined condition of a circuit, said movable contact being biased into engagement to automatically close the circuit in response to a circuit opening operation, overcenter spring means connected between a stationary support and said movable contact for additionally biasing said contacts together at least when they are in engagement, said overcenter spring means being moved in response `to a predetermined small initial part of the contact separating movement of said movable contact substantially to its on-center position, stop means preventing movement of said overcenter spring means overcenter, whereby the remaining contact separating movement is substantially uniniiuenced by said overcenter spring means and said overcenter spring means also being moved by said movable contact during its closing movement to become suddently eiective to close said contacts with a snap action only over said small part of contact movement just prior to nal engagement of said contacts, and means responsive to a predetermined number of closely successive circuit opening operations for holding said movable contact separated from the other of said contacts, and said overcenter spring means at its on-center position,

l2. In a circuit interrupter, separable contacts, resilient means biasing said contacts together at least when they are in engagement, solenoid means having lost motion relative to said contacts for causing separation of said contacts in response to a predetermined condition of a circuit and having a non-linear force-distance charac-A accadevf tristc, spring means `comprising a plurality of spring portions having dierent spring characteristics .arranged so that the force-distance characteristic of said spring means substantially matches that of said solenoid means and adapted tobe stressed during movement of, said.electro responsive means relative to said contacts vvto separate said` contacts, and means connected to said movable contact and said resilient means so as'. to beuresponsive to a predetermined small initial part of the separating movement of said contacts `for rendering said resilient means inoperative to exert any substantial force on said contacts, whereby the remaining contact separating movement is effected by said spring means and is substantially uninfluenced by said resilient means.

13. In an automatic reclosing circuit interrupter, `'separable contacts, electro-responsive means having lost motion relative to said contacts for causing separation of said contacts in response to a predetermined condition of a Vcircuit, said contacts being biased into engagement to automatically close the circuit in response to' a circuit opening operation, resilient means additionally biasing said contacts together in the same direction as said reclosing bias at least When they are in engagement so that con-tact pressure is the sum of the forces exerted by said reclosing bias and said resilient means, spring means adapted to be stressed during movement of=said electro-responsive means relative to said contacts to exert a force tending to separate said contacts which is greater than the resultant force due to said reclosing bias and said resilient means, and means connected to said contacts and said resilient means so as to be responsive to a predetermined small initial part of Vthe separating movement of said contacts for rendering said resilient means inoperative to exert any substantial force on said contacts, whereby the remaining contact separating movement is eiected by said spring means substantially uniniluenced by said resilient means.

14. In an automatic reclosing circuit interrupter, separable contacts at least one'of which is` mounted for movement into and out of engagement with the others, electro-responsive means for causing separation of said contacts in response to a predetermined condition of a circuit, said movable contact being biased into engagement to automatically close the circuit inresponse to a circuit opening operation, overcenter spring means connected. between a stationary support and said movable contact for additionally biasing said contacts together at least when they are in engagement, said overcenter spring means being moved in response to a predetermined small initial part of the contact separating movement of said movable contact substantially to its oncenter position, stop means preventing movement of said overcenter spring means overcenter, whereby the remaining contact separating movement is substantially uninnuenced by said overcenter spring means, and said overcenter spring means also being moved by said movable contact during its closing movement to become suddenly effective to close said contacts with a snap action only over said small part of contact movement just prior to nal engagement of said contacts, contact opening spring means, lockout toggle means normally held at an overcenter position Where it maintains said contact opening spring means inactive, said contact opening spring Incensi-.when released adapted ztormoresaidgoyer-f center spring means in a contact opening direc-I tion. to separate the contacts and hold them separated, and manual means and means responsive to a predetermined number of closely successive circuit opening operations of said interrupter for moving said lockout toggle means overcenter to release said contact opening spring.

means.

l5. In an automatic reclosing circuit inter.- rupter, separable contacts, electro-responsive means for causing separation of said contacts in response to a predetermined condition of a circuit, said contacts being biased into engagement to automatically close `the circuit in response to a circuit opening operation, overcenter spring means additionally biasing said contacts together at least when they are in engagement, said overcenter spring means being moved in response to a predetermined small initial part of the contact separating movement substantially to its oncenter position, stop means preventing movement of said overcenter spring means overcenter, whereby the remaining contact separating movement is substantially uniniluenced by said overcenter spring means and during closing movement of said contact means said overcenter spring means becomes suddenly eiective to close said contacts with a snap action only over said small part of contact movement just prior to nal engagement of said contacts, contact opening spring means, lockout toggle means normally held at an overcenter position where it maintains said con.

tact opening spring means inactive, said contact opening spring means when released adapted to separate the contacts and hold them separated, and manual means and means responsiveV to a predetermined number of closely successive circuit opening operations oi said interrupter for moving said lockout toggle means overcenterto release said contact opening spring means, said manual means also being movable in an opposite direction to reset said lockout toggle means to its normal position and having opposed `surfaces engageable by a manual operating member to move said manual means in both directions respectively, there being no part of said manual means preventing relative separating movement of said member and manual means dur-ing moveresponse .to a predetermined condition of a cir cuit, said contacts being biased into engagement to automatically close the circuit in response to a circuit opening operation, resilient means additionally biasing said contacts together in the same directionas said reclosing bias but with a force greater than that exerted by said reclosing bias at least when they `are in engagement so that contact pressure is the sum of the forces exerted by said reclosing bias and said resilient means, and means movably connected to said contacts and said resilient means and to a relatively stationary point so as to be actuated by said contacts in response to a predetermined small initial part of the separating movement of said contacts for rendering said resilient means inoperative to exert any substantial force on said contacts, whereby the remaining contact separating movement is substantially uninfluenced by said resilient means.

1'7. In an automatic reclosing circuit interrupter,` separable contacts, electro-responsive means .fqisausms separation pf.. said ceniactsin 17 response to a predetermined condition of a circuit, said contacts being biased into engagement to automatically close the circuit in response to a circuit opening operation, overcenter spring means additionally biasing said contacts together in the same direction as said reolosing bias at least when they are in engagement so that contact pressure is the sum of the forces exerted by said reclosing bias and said spring means, said overcenter spring means being moved substantially to its on-center position in response to a predetermined small initial part of the separating movement of said contacts for rendering said overcenter spring means inoperative to exert any substantial force on said contacts, and said overcenter spring means having portions relatively pivotally movable about an axis Which is substantially coincident with said center when said overcenter spring means is substantially at its oncenter position, whereby the remaining contact l separating movement is substantially uninfiuenced by said resilient means.

HERBERT L. RAWLINS. JAMES M. WALLACE.

REFERENCES CITED The *following references are of record in the le of this patent:

UNITED STATES PATENTS

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