US2470608A

US2470608A - Circuit breaker

Info

Publication number: US2470608A
Application number: US545438A
Authority: US
Inventors: Gilbert J Easley; Ralph O Bonine
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1944-07-18
Filing date: 1944-07-18
Publication date: 1949-05-17
Anticipated expiration: 1966-05-17
Also published as: GB594105A

Description

G. J. EASLEY ET AL 2,470,608

CIRCUIT BREAKER 2 Sheets-Sheet l 1 INVENTORS //er j fb/ey'ana/ Halfph O. Bon/ne. f BY l 2 1 J\ @r 7U M ATTORNE May 17, 1949.

Filed July 18, 1944 WITNESSES: d

May 17, 1949. G. J. EASLEY ET AL,

CIRCUIT BREAKER 2. Sheets-Sheet 2 Filed July 18, 1 944 NVENTORS //ber/L .Z [Q5/'ey and 'Ea/,9h @dfb/2706A BY l f' A ATTORNE Patented May 17, 1949 unirse fsf-raras 2,470,608 PATEN T OFFICE CIRCUIT BREAKER .Gilbert J. Easley, Forest Hills, and Ralph O.

Bonino, Edgewood-.Pa., assgnors to'Westnghouse l'Electric Corporation, East Pittsburgh, -'Pa., a corporation of PennsylvaniaI ApplicationJuly 18, 1944, Serial No. 545,438

(Cl. ZOO-82) 15 Claims. `1

inventionrelatesto circuit breakers, and more particularly to vcircuit-breaker operating mechanisms of .the fluid-pressure type..

vin object of the invention is to provide a circuit-breaker operating .mechanism of the uidfpressure operated type having ari-improved exhaust valve for .quickly exhausting the fluid pressure from the 'workingside of .the piston.

Another object of theinvention is to .provide a circuitfbreaker operating vmechanism of the type voperated-by fluid .pressure with an improved high-speed valve ,for .quickly .exhausting the working-fluid pressure.

.Another .objectof the .invention is to provide a iiuid motorfwith .an improved high-speed valve for quickly .exhausting .the working pressure from the motor wherein the valve is `operated by the working pressure .and remains open longer to more completelyexhaust the working lipid pressure.

.Another-.Object of the 'invention iS to provide a .circuit-breaker operating mechanism of the type operated .by `fluid pressure with an improved exhaust valve .for .quickly exhausting the working pressure .wherein the valve is operated Vby the working pressure .admitted to a separate Chamber vfor maintaining said valve open to more completely reducethe working pressure.

.Another object ofthe invention is to provide a circuit-breaker voperating mechanism of the type 4operated 'by fluid pressure with an improved exhaust valve for ,quickly reducing the operating pressure in the mechanism'in which opening movementof the exhaust valve is initiated by a piston, the valve .being moved to full open position 'byfluid pressure, the piston being effective to hold the valve open afterthe pressure vhas been reduced below the value at which the valve would ordinarily close.

The novel features that are considered characteristic ofthe invention are set forth inparticular in the appendedclaims. kThe invention itself, however, both as to structure land operation, together with additional objects and advantagesthereof will best be understoodrfrom the"following,detailed-description of several embodiments thereof `when read in connection with the accompanying drawings, in which:

Figure l is an elevational vview partly in Asection of a circuitfbreaker operating Ymechanism embodying theprinci-ples ofthe invention;

Fig. 2 is a vertical sectional view taken on line II-'II of Fig. l;

FigxBis a vertical sectionalview 4of a modification of the invention; and

Fig. -4 is adetail sectional view of one ofthe adjustable .bleeder valves.

'Referring-tothe drawing-the operating mechanism includes a main-casting l which is formed to provide a cylinder `Iily closed at the upper end by anintegral'part of the casting. The lower end of the Vcylinder isis vclosed by means of a member l5. An operating lever .Illis pivotally mounted at .one end `on .the casting .Il and consists .of `a pair of spaced parallel levers (only one being shown) pivotally connected .at .one end by means of a pivot pin 2l to the upper ends of a pair of parallel links 2.3 (only one .being shown), The lower ends .of thelinks 23 arepivoted .by means of a pivot pin 25 on ears 2] (only one :being shown) projecting from the main casting .|l. The free ends of the operating levers 1.9 are rigidly connected by means ,of .a cross member `29 and carry a short shaftl therebetween, onwhich is .mounted a latch roller 33 disposed between the levers I9.

'The circuit breaker shown .schematically `at 19 is biased to open circuit position by `means of an accelerating spring I] and vis VVconnected to the operating mechanism by means of .an operating `rod 35. The breaker .operating rod 35 is pivotally connected by a pivot pin ,3l to the operating lever 1.9,.

in order to hold the breaker closed, the .operating lever .I9 is hel'd in the closed position by means of a'high speed latching mechanism including a main latch 39 pivotally supported .on the main casting H by means ofa pivot pin 4|. rIhe latch 39 is disposed between the levers .i9 and is adapted to engage the roller `3.3 carried by the free ends of the breaker operating levers l5 to restrain the operating mechanism and the breaker in closed circuit position. 'Ihe latch 39 is biased to latching position against a stop 43 by means of a spring pressed plunger 45 which engages a projection 4.1 of the latch, The plunger 45 is slidably mounted in an opening in a lportion of the main casting Il and is biased inwardly against the projection k4'! of the latch 39 by means of a compression spring 49 surrounding the plunger 45 and disposed between a sleeve 5l threaded into .the casting Il, and the head of the plunger. An adjustable nut 53 -is provided on the outer end of the plunger 45 to limit the inward movement of the plunger.

lThe construction of the latch face of the main latch 39 is such that this latch, by itself, will not serve to hold the breaker voperating lever I9 in latching position.V An auxiliary latch l55 is provided for engaging and hold-ing the main latch 39 in latching position. vThe auxiliary latch -155 is pivotally mounted on the casting 'Il .by means of a pivot -pin 51 and has `a latch projection 59 which engages `under a tail portion 6l of the main latch 39V i-n thellatching position of the latching mechanism. The auxiliary latch 55 is biased to latching position by means of Ia compression spring 63 seated in a recess in the casting vand engaging a projection of the latch 55. lThe lauxiliary latch 55 is also provided with a projection 65 which extends directly over the upper end of a -trip plunger 6T of an electromagnetic trip device 6.9. In addition to the trip plunger 51, the trip device comprises an E-shaped core 'H of magnetic material, an energizing coil 13 mounted on the center leg of the core 1|, and a movable armature 15. The trip plunger 61 is secured to the center portion of the armature 15 and extends upwardly through a guide opening in the center portion of the core 1| and through an opening in the horizontal portion of the main casting |I.

When the trip device 69 is energized, the armature 15 is moved upwardly against the core 1| causing upward movement of the trip plunger B1. The upward move-ment of the trip plunger rotates the auxiliary latch 55 counterclockwise and disengages the projection 6| of the main latch 39, whereupon the accelerating spring 11 of the cir.- cuit breaker, shown schematically at 19, moves the breaker to the open circuit posi-tion, the operating lever I9 being rotated counterclockwise about its pivot 2| by the opening movement of the breaker. movement of the operating lever I9, the roller 33 forces the main latch 39 in a counterclockwise direction as it clears the latch. As soon as the roller 33 clears the main latch I9, the spring i9 acts to return the latch 39 to latching position.

Means is provided to prevent the restoration of the auxiliary latch 55 to its latching position until the operating lever I9 is returned to closed position. This means comprising a U-shaped holding lever 83, the legs of which are pivotally mounted on the pivot pin 51 on opposite sides of the auxiliary latch 55. The holding lever 83 is biased in a counterclockwise direction by a spring 85 compressed between a spring seat in the casting I l and a projection 81 of the holding lever. The cross member 89 of the holding lever 83 is disposed directly beneath the free end of the operating lever I9 and thus is held in inoperative position when the operating lever is in closed position. When the operating lever is released and moves toward open position, the holding lever 83 is rotated counterclockwise at which time a lateral extension 9| of the holding lever 83 engages and holds the auxiliary latch 55 in unlatched position until the breaker operating arm I9 is returned to closed position and the roller 33 is reengaged by the latch face of the main latch 39. For this purpose, the biasing spring 85 of the holding lever 83 is of greater strength than the auxiliary latch biasing spring 63.

The breaker is adapted to be closed by compressed gas admitted to the cylinder I3 above an operating piston 93. The piston 93 is secured to a piston rod 95 slidable through an air-tight opening inthe top wall of the cylinder Il. A connector 91 is threadedly connected to the piston rod 95 and pivotally connected to the pivot pin 31 carried by the operating lever I9, thus directly connecting the piston 93 to the breaker operating rod 35.

, Compressed air is admitted from an auxiliary air reservoir or tank (not shown) to the upper end of the cylinder I3 through an inlet passage controlled by a main inlet valve indicated generally at |03 secured to the side of the casting II. The opening operation of the main inlet valve 03 is, in turn, controlled by an electromagnetically operated pilot valve |05. The main inlet valve |03 and the pilot valve |05 are fully disclosed in copending application Serial No. 410,686, led September 13, 1941, of J. M. Cumming and R. C. Cunningham now Patent No. 2,408,199, issued September 24, 1946, and assigned to the assignee of the present invention. For this reason, a detailed disclosure of these elements is During the early part of the opening not included herein since, for a complete understanding thereof, reference may be had to the above-noted application.

The pilot valve |05 is operated by an electromagnet |01 which, when energized, causes opening of the pilot valve |05 to admit compressed air from the tank to operate the main inlet valve |03. Actuation of the inlet valve admits compressed air to the upper end of the operating cylinder I3 which drives the piston quickly downwardly to close the breaker.

When the mechanism is operated to closed position, the operating lever i9 rotates in a clockwise direction, and near the end of this clockwise travel, the roller 33 engages the inclined surface of the main latch 39. As the roller passes along this inclined surface, the latch 39 is rotated counterclockwise until the roller passes the nose of the latch whereupon the retrieving spring 49 restores the main latch 39 to latching position. As the roller 33 passes the nose of the main latch 39, the cross member 29 on the free end of the operating lever I9 engages the free end of the holding lever 83 and rotates the holding lever clockwise to its normal position permitting the spring 63 to restore the auxiliary latch 55 clockwise to latching position.

When the breaker is opened on a normal opening operation, the gas in the cylinder above the piston 93 is at atmospheric pressure, and offers little resistance to the opening movement of the piston by the spring 11. This gas is compressed slightly by the opening movement of the piston and serves to absorb the kinetic energy of the moving parts at the end of the opening stroke. When the breaker is being, or has just been, closed by the application of gas pressure above the piston 93, and there is a fault existing on the line, the trip device is actuated and the breaker mechanism reverses its direction of movement and moves toward the open position. At this time the gas in the cylinder is at or near full closing pressure and it is necessary to quickly exhaust the closing gas pressure in order to permit quick reversal of the parts and opening of the contacts to thereby prevent damage to the breaker parts and to prevent damage to translating devices operated by the current of the circuit controlled by the breaker.

An important feature of the invention is the provision of an exhaust valve mechanism in which the opening movement of the valve is initiated by iiuid pressure admitted thereto by means of an elec-tromagnetically operated pilot valve, the exhaust valve being moved to full open position by the blast of exhausting iluid pressure from the operating cylinder, and in which the exhaust A valve is maintained in its open position by the initiating opening pressure after the pressure of the exhausting fluid has fallen below the point at which the valve would ordinarily close. The exhaust valve |09 is supported for operation in a housing (Figs. 1 and 2) secured by means of bolts I3 to the side of the main casting II. The exhaust valve is disposed for sliding movement in the cylindrical lower portion I5 of the housing I and is biased to closed position by means of a compression spring I 1. The exhaust valve |09 comprises a multiple valve member I9 slidable in the valve cylinder |15. A plurality of piston-type valves |2I, formed integral with the valve member H9, cooperate with a plurality of exhaust ports |23 extending throughthe walls of the cylinder ||5 and communicate the main operating cylinder I3 through an opening |24 (Fig,

2) in the cylinder wall and-a chamber |25 in'the upperpart of thehousingl |I tothe atmosphere. The exhaust ports, however.,lare normallyclosed by the piston valves |21` The spring-|11, which biases the valve member: 1'119 andthe piston valves thereon to closed position, is .disposed in the lefthand end ofthe valve cylinderil 1:5, one end bearing against the left-hand .end of the valve member 119. The end wall of the cylinder l is provided with an opening |21 to, prevent trapping of air between the left-handpiston valve 12| andthe end wall of the cylinder.

Disposed-in a cylinder |129, whichiorrns an extension of the main exhaust vvalve cylinder 115 and is rigidly secured thereto, is a pilot piston 13.1 which has an integral stem |33 against which the separate exhaust valve member |19 .bears in the closed position. The spring |`|1 normally biases the exhaust valve and the pilot piston 13| against an adjustable stopscrew |35 .disposed in the righthand end of the extension cylinder |29. The purpose of the adjustable .screw `135 is to adjust the position of the main exhaust valve. The chamber |25 communicates directly with the main operating cylinder Vlivand, by means of passages |31 and 138 in the extension cylinder |29, communicates the cylinder 13 to the extension cylinder |29 at the working side of the pilot piston 13 An electromagnetically operated pilot valve 139 disposedin the passage 1 31 controls the admission of compressed fluid fromlthe main operating cylinder 13 to the exten-sion cylinder 129 to effect operation of the ypilot piston |31 and opening of the exhaust Valve. The valve |39 is mounted on the lower end of va rod 14|, the upper end of which has a lost-motion connection with the movable armature 143 ci an electromagnet 145. The electromagnet |45 is rigidly mounted on insulating member |41 which in turn, mounted on a sleeve |48, threadedly engaging in .an opening |51 in the cylinder extension |29. In order to prevent compressed gas, which might leak past the righthand piston valve ,|21 into-the space between said piston valve and the. pilot piston=|31', from falsely opening the exhaust valve, there is provided a bleeder valve 153 .(Figsl, 2 and 4) comprising a screw having :a Teshaped opening 155 therein communicating with the space between the exhaust valve and the-pilot piston |31 to the atmosphere. The bleeder valve |53 `is screwed into an opening in the cylinder extension |29 and is provided with a lock nut .151 for locking the bleeder valve in the adjusted position. A second bleeder valve 159 of similar construction is disposed in the end of the cylinder extension |29 and serves to connect .the passage 138 and the space to the right of the pilot piston |31 to the atmosphere. Both of the bleeder valves |53 and 159 are adjustable to vary the rate at which the uid ypressure escapes therethrough.

Assuming that the breaker is in the open position with the piston 93 (Fig. 1) in the upper end of the operating cylinder 13 and that the inlet valve 103 has functioned to admit fluid pressure tothe cylinder abovey thepiston 93, the operation of the exhaust valve mechanism is described -as follows:

As the piston `9.3 in its ldownward or `closing movement passes the exhaust port or opening 1.24, the closing iluid pressure expands into the chamber 125, but `since the exhaust valve |09 and the pilot valve 139 are closedlat this time, the closing pressure in the :oper-ating cylinder is maintained. Just before the Ipiston 93 and the breakeroperating mechanism reach the end o! the closing movement, the breaker contacts touch, and, if at this time, an overload exists on the circuit controlled bythe breaker, the trip device 69 will function to release the latch mech-- anism and permit the accelerating spring11t0 quickly reverse the direction of movement ofthe mechanism and operate the breaker contacts to open position. At this time, however, the full closing fluid pressure is in the cylinder and,ain order to obtain high speed reversal of the mechanism, it is necessary to dump the' closing fluid pressure to atmosphere with the highest possible speed. Simultaneously with the energization of the trip device B9, the electromagnet |45 is energized and opens the pilot valve-139 whereupon the closing fluid pressure in the cylinder 13 is admitted through the passages |31- 138 to the cylinder 129 to the right of the pilot piston 131 which is immediately moved toward the left, moving the exhaust valve 1.09 therewith and opening the exhaust ports 123. As soon as the piston type valves |21 are cracked open, the rush of compressed fluid through the ports `1 23 blasts the exhaust valve |09 to full open position independently of pilot piston 13|. At the same time, the iiuid pressure built up in the working end of the cylinder |29 back of the pilot piston 13| moves this piston to the left. When the pressure in the main operating cylinder is reduced to a given value, the spring |11 acts to close the exhaust valve, but since the fluid pressure trapped back of the piston 13| exhausts slowly to the atmosphere through the bleeder valve |59, the pilot piston is held far enough to the left to maintain the exhaust valve open for a predetermined time after the closing pressure in the cylinder 13 has fallen below a given value, thus more completely venting the operating cylinder. As soon as the trapped fluid pressure is exhausted from the cylinderlZ-Q, the spring |11 closes the exhaust valve IGS an-d restores the pilot piston to its normal position in the end of the cylinder 129.

According to the modication of the invention illustrated in Fig. 3, advantage is taken of the leakage of fluid pressure around the exhaust Valve to initiate opening movement of the exhaust valve. Referring to Fig. 3, the singlepiston type exhaust valve |61 is mounted for vertical movement in cylinder 163 formed in a housing |65. The housing |65 is suitably secured to the wall of the operating cylinder 13 (shown completely in Fig. l) and is provided with an exhaust passage 161 in alignment with an exhaust port 1&9 in the wall of the operating cylinder. The lower end of the exhaust valve cylinder 163 is closed by means of a plate 11| attached thereto by means of screws 113. The plate serves to support a spring |15 which biases the exhaust valve |61 to closed position. Disposed in -a chamber |11 is a normally open valve 119 which is adapted to close a vent or bleeder opening 181. The vent |81 is for the purpose of venting leakage pressure from the operating cylinder, the leakage passing through the vent 181, the chamber |11 and through an opening |83 through the wall of the chamber .111. The Valve 119 lis mounted on the lower end of a valve rod which has its upper. end secured to the armature |81 of an electrcmagnet |89. A spring |91 normally biases the armature |81 to unattracted position and the Valve |19 to open position.

On the normal closing operation, as the operating piston 93 (Fig. l) passes below the exhaust port 169 (Fig. 3), the closing `'fluid pressure is retained in the `opera-ting cylinder 13 by the closed exhaust valve |6I, a small amount of compressed fluid leaking past the exhaust valve and to atmosphere through the vent |8l. Should the breaker be closed in against a fault existing on the main circuit, the trip device 69 (Fig. l) would be energized to eiect high speed reversal of the mechanism and opening of the breaker. At the same time the trip device is energized, the electromagnet |89 is also energized and moves the valve |19 to closed position thereby closing the vent |8|. The closing pressure in the operating cylinder is trapped above the exhaust valve |6| and immediately moves this valve in opening direction. As soon as the exhaust valve is cracked, the rush of compressed gas past the valve blasts it to its fully opened position, thus quickly dumping the closing gas pressure from the operating cylinder to permit high speed opening movement of the circuit breaker mechanism. The exhaust valve |6| is closed by the spring |75 when the pressure in the cylinder is reduced to a predetermined value or when the operating piston 96 passes above the exhaust port |69.

Having described several embodiments of the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the structural details thereof without departing from some of the essential features of the invention. It is, therefore, desired that the language of the appended claims be given as reasonably broad interpretation as the prior art permits.

We claim as our invention:

l. An operating mechanism for a circuit breaker comprising a fluid motor, means for admitting fluid pressure to said motor to operate said breaker to closed position, a valve operable to an open position during a closing operation of said motor to cause quick collapse of the uid pressure on the working side of said motor, actuating means comprising a valve actuating piston operable by fluid pressure to initiate an opening operation of said valve, said valve being operable by fluid pressure to full open position independently of said valve actuating piston following said initial opening operation thereof,

2. In an operating mechanism for a circuit breaker, fluid pressure operated means for closing the breaker, an inlet valve operable to admit fluid pressure to effect closing of said breaker, a valve operable to quickly reduce the pressure in said pressure operated means, actuating means comprising a valve actuating piston operated by iluid pressure for moving said Valve a predetermined distance in opening direction to admit fluid pressure to one end of said valve, said valve being operable by fluid pressure independently of said valve actuating piston to full open position following said initial `opening movement thereof, and means for holding said actuating piston in a position for restraining said valve in open position for a predetermined time after the pressure in said pressure operated means is reduced below a predetermined value.

3. In an operating mechanism for a circuit breaker, means comprising a uid motor operable to close said breaker, means operable to admit uid pressure to said motor to effect closing of said breaker, means comprising a cylinder and a valve operable therein to cause collapse of the fluid pressure in said motor, actuating means comprising a valve actuating piston disposed in one end of said cylinder and operable by iluid pressure to initiate opening movement of said valve, and means for admitting iluid pressure to said one end of said cylinder for operating said valve actuating piston, said valve being operable to full open position by fluid pressure independently of said piston following said initial opening movement thereof.

4. In an operating mechanism for a circuit breaker, means comprising a fluid motor operable to close said breaker, means operable to admit fluid pressure to said motor to effect closing of said breaker, means comprising a cylinder and a valve operable therein to cause collapse of the fluid pressure in said motor, actuating means for said valve comprising a piston disposed in one end of said cylinder and operable by iiuid pressure to initiate opening movement of said valve, and means for admitting fluid pressure to said one end of said cylinder for operating said piston, said valve being operable to full open position by fluid pressure independently of said piston following said initial opening movement thereof, and means for trapping fluid pressure in said one end of said cylinder to hold said piston in a position to hold said valve open for a predetermined time.

5. In an operating mechanism for a circuit breaker comprising a fluid motor, means for admitting fluid pressure to said motor to operate said breaker to closed position, means comprising a cylinder and a valve operable therein to cause quick collapse of the fluid pressure in said motor, means biasing said valve to closed position, actuating means for said valve comprising a piston clisposed in one end of said cylinder and operable by fluid pressure to initiate opening movement of said valve, means operable during a closing operation of said motor to admit fluid pressure to said one end of said cylinder, said valve being operable to full open position by fluid pressure independently of said piston following said initial opening movement thereof, and means for holding said piston in a position wherein it maintains said valve open against the force of said spring after the iluid pressure in said motor has collapsed below a predetermined value.

6. In an operating mechanism for a circuit breaker comprising a uid motor, means comprising an inlet valve operable to admit fluid pressure to said motor to operate said breaker to closed position, an exhaust valve operable to cause collapse of the uid pressure in said motor, actuating means comprising valve actuating piston operable by compressed fluid for actuating said exhaust valve a predetermined distance in opening direction, said exhaust valve following said predetermined actuation thereof being operated to full open position by fluid pressure independently of said actuating piston, an electromagnetically operable valve for admitting iiuid pressure to said actuating means.

'7. In a circuit breaker comprising relatively movable contacts, operating mechanism for said contacts comprising a fluid motor, means for admitting fluid pressure to said motor to operate said contacts to closed position, a trip device operable in response to abnormal circuit conditions to effect opening of said contacts, a first valve operable to open a passage to cause quick collapse of the iluid pressure on the working side of said motor, means comprising a valve actuating piston for initiating operation of said Valve, a second valve operable mechanically independently of said trip device to cause the uid pressure from the working side of said motor to operate said valve actuating piston, said rst valve following the initial operation thereof being operable independently of said valve actuating piston to full open position by direct force of the Working fluid pressure, and means for causing said Valve actuating piston to hold said first valve open after the working fluid pressure in said motor has decreased to a predetermined value.

8. In an operating mechanism for a circuit breaker comprising a fluid motor, means for admitting fluid pressure to said motor to operate said breaker to closed position, means comprising a cylinder and a plurality of piston type Valves operable in said cylinder to open a plurality of passages to thereby cause quick collapse of the fluid pressure on the working side of said motor, spring means disposed in one end of said cylinder for biasing said Valves to closed position and for moving said valves to closed position following an opening operation thereof, a valve actuating piston disposed in the other end of said cylinder and operable by fluid pressure to effect opening of said valves, means operable to admit fluid pressure to said other end of said cylinder to operate said piston, and means for trapping the fluid pressure back of said piston to maintain said valves open for a predetermined time.

9. In an operating mechanism for a circuit breaker comprising a fluid motor, means for admitting fluid pressure to said motor to operate said breaker to closed position, means comprising a Valve biased to closed position and operable to open position by fluid pressure to cause quick collapse of the fluid pressure in said motor, means comprising a passage disposed to vent duid pressure leaking past said valve, and a second valve operable to close said passage to thereby cause the leaking iluid pressure to initiate opening movement of the rst named valve.

10. In an operating mechanism for a circuit breaker comprising a fluid motor, means for admitting fluid pressure to said motor to operate said breaker to closed position, means comprising a valve biased to closed position and operable to open position by fluid pressure to cause quick collapse of the fluid pressure in said motor, means comprising a passage disposed to vent uid pressure leaking past said valve, and a second valve operable to close said passage to thereby cause the leaking iluid pressure to initiate opening movement of the rst named valve, said first named valve being moved to full open position by fluid pressure.

11. In an operating mechanism for a circuit breaker comprising a fluid motor, means for admitting fluid pressure to said motor to operate said breaker to closed position, an exhaust valve operable to quickly reduce the fluid pressure in said motor, means comprising a passage disposed to normally vent fluid pressure leaking to the top of said exhaust valve, and means comprising an electromagnetically operable valve for closing said passage to thereby cause the fluid pressure to initiate operation of said exhaust valve.

12. In a circuit breaker comprising relatively movable contacts, operating mechanism for said contacts comprising a fluid motor, means for admitting fluid pressure to said motor to operate said contacts to closed position, a trip device operable in response to predetermined circuit conditions to effect opening of said contacts, an exhaust valve movable to an open position to cause quick collapse of the working pressure in said motor, valve means operable mechanically independently of said trip device to cause the 10 Working pressure in said motor to initiate opening movement of said exhaust valve, and said exhaust valve being constructed and arranged to be moved to full open position directly by the exhaust blast of the working pressure following said initial opening movement thereof.

13. A circuit breaker operating mechanism comprising a fluid motor, means for admitting iluid pressure to said motor to operate said breaker to closed position, a Valve operable to an open position during a closing operation of said mechanism to cause quick collapse of iluid pressure on the Working side of said motor, a valve actuating piston operable by fluid pressure to initiate opening movement of said valve, said valve being constructed and arranged to be moved to lull open position independently of said valve actuating piston following said initial operation movement thereof, and adjusting means for adjusting the position of said valve actuating piston in the closed position of said valve.

14. An operating mechanism for a circuit breaker comprising a fluid motor, means for admitting fluid pressure to said motor to effect closing of said breaker, means comprising a cylinder and a valve operable therein to cause collapse of the fluid pressure in said motor, an actuating piston disposed in one end of said cylinder and operable by fluid pressure to initiate opening movement of said valve, means for admitting fluid pressure to said one end of said cylinder for operating said piston, said Valve being constructed and arranged to be moved to full open position by iluid pressure independently oi' said actuating piston following said initial operation movement thereof, means for trapping fluid pressure in said one end of said cylinder to hold said piston in a position to hold said valve open for a predetermined time, and adjustable valve means for exhausting the trapped fluid pressure from said one end of said cylinder.

15. An operating mechanism for a circuit breaker comprising a fluid motor, means comprising an inlet valve operable to admit fluid pressure to said motor to operate said breaker to Closed position, tripping means operable to effect opening of said breaker, exhaust valve means movable to an open position by the working pressure in said motor to cause collapse of the working pressure in said motor, electromagnetically operated valve means separate from said tripping means to cause the working pressure in said motor to initiate opening movement of said exhaust valve means, and said exhaust valve being constructed and arranged to be moved to full open position by the direct force of the exhausting working pressure following said initial opening movement thereof.

GILBERT J. EASLEY. RALPH O. BONINE.

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

UNITED STATES PATENTS Number Name Date 1,836,813 Rankin Dec. 15, 1931 1,873,787 Rankin Aug. 23, 1932 2,286,023 Strang June 9, 1942 2,349,650 Cumming et al. May 23, 1944. 2,379,178 Peek June 26, 1945 2,408,199 Cumming et al. Sept. 24, 1946