US2765378A

US2765378A - Circuit breaker with hydraulic motor controlled by a hydraulically biased valve

Info

Publication number: US2765378A
Application number: US357444A
Authority: US
Inventors: Perry Elijah Robert; Nicholas W Morelli
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1953-05-26
Filing date: 1953-05-26
Publication date: 1956-10-02
Anticipated expiration: 1973-10-02
Also published as: GB752947A

Description

Oct. 2, 1956 PERRY ET AL 2,765,378

MOTOR CONTROLLED CIRCUIT BREAKER WITH HYDRAULIC BY A HYDRAULICALLY BIASEZD VALVE 2 Sheefs-Sheet 1 Filed May 26. 1953 5 Z 4 J a f M 0 m a p 7 4 7 H 0. 9 00 5 MM L 6 fi m/ 7 l u 6 01. 63 A7 6 6 6 0 a E: m 5 7 00M.

Oct. 2, 1956 E. R. PERRY ET AL 2,765,378 CIRCUIT BREAKER WITH HYDRAULIC MOTOR CONTROLLED BY A HYDRAULICALLY BIASED VALVE Filed May 26, 1953 2 Sheets-Sheet 2 JMO/my United States Patent CIRCUIT BREAKER WITH HYDRAULIC MOTOR CONTROLLED BY A HYDRAULICALLY BIASED VALVE Elijah Robert Perry, Stoughton, and Nicholas W. Morelli,

Westwood, Mass., assignors to Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

Application May 26, 1953, Serial No. 357,444

13 Claims. (Cl. 20082) This invention relates to circuit breaker operating systems and more particularly to high speed circuit breaker operating devices which use energy stored in pneumohydrauli-c accumulator for closing pairs of arcing contacts.

The operation of a high capacity circuit breaker requires an energy storage device which will substantially instantaneously release a tremendous quantity of energy. The closing operation of a typical high capacity circuit breaker may demand as much as 130,000 inch pounds of effort delivered during one-tenth of a second. This is approximately two hundred horsepower. It is not economical to provide a continuous source of power of such a value. Hence, energy storage at the location in the form of storage batteries, compressed air, or springs, has been the conventional solution. These system-s have all been handicapped by the means required to translate the stored energy into final mechanical motion, or by the complex methods of the original translation of energy to the bulky storage means.

A-s circuit breakers are frequently required to operate in isolated locations, an operating mechanism which requires a minimum of maintenance is imperative.

The hydraulic operating mechanism described herein is proved to meet all of the requirements of a circuit breaker prime mover. This particular arrangement of the hydraulic operating mechanism couples a pneumohydraulic system with a mechanical trip free operator. It should be understood, however, that other arrangements can be made similarly adaptable to the nontrip free and electrically trip free types of operator without departing from the spirit of this invention.

Hydraulic systems have certain characteristics which make them desirable as an operating medium. The incompressibility of liquids permits the instantaneous transmission of power between two points as with a mechanical linkage. Unlike the mechanical linkage however, liquids can be transmitted through tubes in all directions without loss of function and without the use of bell cranks or other bulky or complicated apparatus. Bearings and guides are unnecessary. Transformation and translation of power can be easily and simply accomplished. Compactness is an inherent characteristic of modern high pressure hydraulic systems.

The new and improved hydraulic system disclosed herein was arranged to meet six major requirements, namely:

'1. Simple and rugged design.

2. Greater dependability than with the prior art structures.

3. Greater ease of maintenance than with the prior art structures.

'4. Higher speed of operation than with the prior art structures.

5. Manual operation under load.

.6. At least five operations stored in the hydraulic systerm.

"ice

This new and improved hydraulic mechanism solved three major problems of the prior art by:

1. Providing means of energy storage which meets the requirements of releasing a tremendous amount of power for a short period of time and is reliable and 'unaifected by temperature variations.

2. Providing a reliable hydraulic valve of simple and rugged design which is capable of high speed operation.

3. Providing a compact hydraulic system which reduces the volume of fluid flow and utilizes reasonable fluid velocities while maintaining maximum efiiciency.

In accordance with this invention a new and improved device is provided which employs a pneumo-hydraulic accumulator controlled by an electrically actuated control valve means for producing an oil flow to a motor comprising a cylinder and a piston for controlling the movement of a pair of arcing contacts. The control valve means admits liquid under pressure to the cylinder of the motor and exhausts jets of liquid under high velocity of the piston from the cylinder of the motor. The valve means comprises a valve cylinder, a valve element, a first orifice in the valve cylinder for directing liquid under pressure to the motor, and a second orifice in the valve cylinder to direct exhaust liquid under pressure from the motor into the valve cylinder. An actuating means such as a solenoid is used to move the valve element to cause liquid to move through the first and second orifices. The valve element is formed to provide land surfaces separated by grooves. The grooves on the downstream sides of the orifices are shaped to direct the turbulent part of the jets of exhaust liquid against the valve element to aid the solenoid in actuating the valve element.

In this invention the normal time constant for the closing operation of a high speed reclosing circuit breaker system, which imposes the demand for a transient rather than a steady state condition of fluid flow in a hydraulic operator, is recognized. This new and improved operating system can be made to utilize effectively the extraordinary high rates of fluid flow that are obtainable within the limits of the hydraulic transient period of the operator. Hence, because of the transient type of fluid flow required in this operator, the rate of fiow may be made very high for the size of the component parts without undue friction losses. Test results show that excessive flows over very short periods of time, as encountered in this device, do not result in excessive pressure drops or friction losses.

It is, therefore, one object of the present invention to provide a new and improved control arrangement for controlling the opening and closing velocities of the movable contacts of a circuit breaker structure.

Another object of this invention is to provide a new and improved circuit breaker operating system in which the liquid flow through the valve means which controls the flow of liquid to the contact actuating motor aids the actuation of the valve means.

A further object of this invention is to provide a new and improved circuit breaker operating system in which the turbulent part of the exhaust liquid expelled from the contact actuating motor into the valve means controlling the contact actuating motor aids in actuating the valve means to obtain rapid circuit breaker operation.

A still further object of this invention is to provide a circuit breaker operating system in which the opening and reclosing speeds thereof are not affected by the ambient temperature, corrosive atmosphere in the immediate vicinity of the operator, or long periods of inactivity of the operator.

Other objects and advantages of this invention will be apparent from the description when read in connection with the accompanying drawings, in which:

Fig. 1 represents, partly in section, a circuit breaker operating system in contact closed position embodying the present invention;

Fig. 2 is an enlarged partial view of the valve means controlling the contact actuating motor shown in Fig. i;

Fig. 3 is a modification, ofthe valve means used to control the contact actuating motor illustrated in Fig. i;

Fig. 4 is an end view of the valve means shown in Fig. 3 with the solenoid actuating means omitted;

Fig. 5 is a horizontal cross sectional view through the valve means taken along the line V-V in Fig. 3; and

Fig. 6 is a vertical cross sectional view through the valve means taken along the line VI-VI in Fig. 3.

Referring more particularly to the drawings by characters of reference, Fig. 1 illustrates a hydraulically operating trip free mechanism 11 for a circuit breaker 12. The hydraulically operating trip free mechanism 1.1 ornprises a hydraulic double acting motor 13 of the cylinder and piston type and a trip free type linkage 14. Motor 13 and circuit breaker 12 are operatively connected by linkage 14.

As diagrammatically shown, the circuit breaker 12 comprises a pair of stationary contact members 15 and a movable contact member 16. The circuit breaker 12 is biased to open circuit position by means of accelerating spring 17. The movable contact member 16 is supported by a breaker rod 18 which, in turn, is supported by lever 19 pivoted at 20. Lever 19 is connected to the trip free operating linkage 14 by means of operating rod 21.

The operating linkage 14 comprises a lever 22 pivoted at 23 and a lever 24 pivoted at 25.

Levers

22 and 24 are interconnected by a toggle comprising two

toggle elements

26 and 27. Toggle element 26 is pivotally connected to lever 24 by a pin carrying a roller 28, and toggle element 27 is pivotally connected at 29 to lever 22

Toggle elements

26 and 27 are pivotally joined together by a pin 30. Pin 38 supports a roller 31 which is acted upon by an operating ram 32.

In the contact closed position of the operating linkage 14, the upper position of pin 38 and roller 31 is controlled by an abutment 36. This abutment is made of any suitable resilient material and is adapted to minimize vibrations of the frame of the trip free mechanism 11. due to the impact of linkage 14 upon abutment in the closed position of the circuit breaker 12, pin 30- forming the joint or connection between

toggle elements

26 and 27 is supported by a spring biased prop 33-. Spring 34 resets linkage 14 upon a trip free operation. Spring 3 is secured at one end on the frame of the trip free operating mechanism 11 and at the other end to a lug 35 of toggle element 27.

The circuit breaker 12 is tripped by spring 17 upon a predetermined movement of a tripping mechanism 44 Tripping mechanism 48 comprises a first lever 41 pivoted at 12, a second lever 13 pivoted at 44 and a trip solenoid 45' comprising a plunger 16 adapted to act on lever 43. Plun er 46 can be operated either electromagnetically by energizing solenoid 45 or mechanically by manual means. i. e., by operation of a lever 47 pivoted at 48. Upon rotation of lever 43 about point 44 in the counterclockwise direction, lever 41 is free to pivot about pin 42 in the counterclockwise direction under the action of a force component transmitted to it by roller 28. The counterclockwise rotation of lever 41 causes counterclockwise movement of lever 24 followed by collapse of the toggle formed by

toggle elements

26 and 27 and return of lever 24 to the position shown to cause the separation of the circuit breaker contacts 15, 16.

In order to close the circuit breaker 12, a suitable liquid under pressure such as oil is admitted to hydraulic motor 13-which comprises a cylinder 7, a piston 8, and ram 32, from a reservoir of stored energy. In this hydraulic system energy is stored in a pneumo-hydraulic accumulator 58 which comprises a homogeneous, seamless, high pressure shell 51, cylindrical in shapeand spun semispherical at either end. One-end has an opening for a gas valve 52 which is molded to a pear shaped synthetic rubber bladder 53. The other end of accumulator 58 has an opening 54 provided with a plug assembly 55. corporated in the plug assembly 55 is a poppet valve 56 which seals 01f opening 54 when the oil is completely expelled from shell 51. This action prevents the bladder 53 from extruding through the opening 54.

The accumulator bladder 53 is precharged with dry nitrogen to approximately two-thirds of. the desired system operating pressure. With no oil in the accumulator, bladder fills the entire interior of the accumulator shell 51. As oil is forced into the accumulator 58 from a reservoir 60 by means of a hand pump 61 or a motor driven pump 62, it compresses the bladder 53 and the pressure rises in accordance with Boyles law. The only permanent stress which the bladder encounters is compression of its Walls which is equal to the systems or precharged pressure. To insure proper operation throughout the temperature range encountered in circuit breaker applications, a commercial oil having a nearly fiat viscosity curve is chosen as the operating medium.

Accumulator 50 is connected to motor 13 through a high speed solenoid actuated control valve 64. Control valve 64 comprises a valve cylinder 65, a valve element 66, valve elements or

land surfaces

67, 68, 69 and 70, and

inlet orifices

71 and 72 and outlet orifices 7'3 and 74 arranged in valve cylinder 65. Orifices 72 and 73 are shown open in Fig. l and orifices 71 and 74 are shown closed by valve element 66.

The valve structure shown in Figs. 3 to 6 is similar to the valve structure shown in Fig. l and like elements have identical reference characters. The valve structure shown in Figs. 3' to 6 differs principally from the valve structure shown in Fig. l in the arrangement of the solenoid actuating means and the positions of the liquid inlet and outlet passages to the valve cylinder 65.

Land surfaces 67 and 68 are separated by a groove 76 formed in valve element 66 and form with a groove in valve cylinder 65 a chamber 80. Land surfaces 69 and 79 are separated by a groove 78 formed in valve element 66 and form with a groove '77 formed in valve cylinder 65 a chamber 81. Chamber 80 is adjacent and downstream of orifice 74 and chamber 81 is adjacent and downstream of orifice 73.

When the valve stem of the four way valve 64 is displaced to the right of its neutral position as shown in Figs. 1, 3 and 5, liquid under pressure will flow from the accumulator 50 through pipe 82, inlet chamber 83 in valve cylinder 65, orifice 72, pipe 97, orifice 84 into cylinder 7 of motor 13 above piston 8. The liquid under pressure from accumulator 50 will force piston 8 downward. Upon the downward movement of piston 8 a jet of exhaust liquid below piston 8 is expelled from cylinder 7 through pipe 79, orifice 73, chamber 81, orifice 85, pipe 86 into reservoir 60.

If the valve stem 66 is displaced to the left, the sequence of-liquid flow is from chamber 83, through orifice 71, pipe 79 and into cylinder 7 of'motor 13 below piston 8. Upon the actuation of piston 8 upward liquid is expelled by piston 8 from cylinder 7 through orifice 8 1, pipe 97, orifice 74, chamber 80, orifice 87, pipe 86 into reservoir 60.

Groove 76 of chamber 80 and groove 78 of chamber 81 in valve element 66 are arranged to provide relatively steep upstream slopes 88 and relatively flat downstream slopes 89 as best seen in Fig. 2. The exhaust liquid from cylinder 7 of motor 13 is expelled in the form of jets of liquid through exhaust orifices 73 and 74 against surfaces 88 but away from surfaces 89 of grooves 76 and 78 in valve element 66 and toward surfaces 90 of grooves 75 and 77 in valve cylinder 65. Grooves 75 and 77 in valve cylinder 65 are shaped to direct the turbulent part of the jets of liquid from the exhaust orifices 73 and 74 having passed over the relatively steep sloped surfaces 88 of valve element 66back again against the relatively steep slope surfaces 88 of valve element 66 to aid the solenoid actuating means 95 in moving valve element 66 to the right or left.

Experiments have shown that if the influx angle of the jets of liquid through the exhaust orifices 73 and 74 and the slope of surfaces 88 are approximately 69 degrees with the longitudinal axis of valve element 66 and the slopes 89 are arranged approximately 45 degrees with the longitudinal axis of valve element 66, the turbulent part of the jets of liquid through the exhaust orifices 73 and 74 will materially aid the solenoid actuating member 95 in moving the valve element 66. A manual means 96 is provided to actuate control valve 64, if desired.

Fig. 2 illustrates the liquid flow through chamber 81 of valve 64. It is possible to substitute either

chamber

80 or 81 for chamber 83 and chamber 83 for

chambers

80 and 81. In this manner the jets of liquid flowing from accumulator 58 through pipe 82 into a chamber similar to 80 or 81 formed by grooves having a relatively steep upstream slope like surface 88 and a relatively flat downstream slope like surface 89 would aid the actuation of valve element 66 before the liquid flowed into cylinder 7 of motor 13 to actuate piston 8.

The speed of operation of the pneurno-hydraulic operating system is determined by the velocity flow of liquid through the system. The velocity flow of liquid through the system is determined by the horsepower requirements of the circuit breaker, the pressure of the operating system and the pipe size of the system. The higher the system pressure, the greater the horsepower per cubic inch of liquid. It is desirable to use as high a pressure as practicable to keep the volume of liquid to be moved to a minimum. The choice of pressures to be used is one of economy and reliability. A pressure of three thousand pounds per square inch was found to be acceptable. The pipe size of the system was determined by the liquid volume and velocity relationship required. All pipe lines are kept as short as possible and with smooth bends where needed.

The circuit breaker system in the drawings is shown with the contacts 15 and 16 in the closed circuit position and the tripping mechanism in a corresponding position. Upon the energization of trip solenoid 45, plunger 46 actuates lever 43 counterclockwise about point 44. After a predetermined movement of lever 43, lever 41 is released to rotate counterclockwise about point 42 under the action of a force component transmitted to it from roller 28. The counterclockwise rotation of lever 41 releases or unlocks the tripping mechanism 14. Upon counterclockwise movement of lever 41, roller 28 moves upward under the action of spring 34 causing the collapse of the toggle formed by

elements

26 and 27 and the separation of contacts 15, 16. During the collapse of

elements

26, 27, pin 30 slides on prop 33.

Upon the complete collapse of the toggle formed by

elements

26, 27, roller 28 settles back on its support 37, and lever 41 rotates clockwise under its biasing means to its original position where it holds roller 28 against its support 37. Trip latch 43 rotates back to its original position by the action of a spring biasing means (not shown) to hold lever 41 in its original position.

To close the circuit breaker contacts 15 and 16 and to return the trip free linkage 14 to the position shown in Fig. l, solenoid actuating means 95 is energized. Because of the small time constant of the solenoid, the current therein rapidly reaches its full intensity to actuate valve element 66 to the left to permit liquid under pressure to flow from accumulator 50 through pipe 82, inlet chamber 83, orifice 71 into cylinder 7 of motor 13 below piston 8. At the same instant pipe 97 connected to the upper end of cylinder 8 of motor 13 provides an escape path for the liquid contained in the upper part of cylinder 7 through control valve 64, pipe 86 to reservoir 60.

In accordance with the invention claimed the kinetic energy of the exhaust liquid expelled under high velocity by piston 8 of motor 13 through valve 64 is utilized to aid the solenoid actuating means to rapidly movethe valve element 66 from its extreme right position to its extreme left position.

The flow of liquid under pressure into cylinder 7 of motor 13 through pipe 79 causespiston 8 and ram 32 to move upward. The closing force of motor 13 is applied to linkage 14 by engagement of ram 32 with roller 31.

Toggle elements

26 and 27 in moving upward during a closing stroke of piston 8, rotate lever 22 about its pivot point 23 in the counterclockwise direction. That rotary motion of lever 22 causes operating rod 21 to move downward. The downward movement of rod 21 causes lever 19 to rotate counterclockwise about its pin 20, thereby closing the breaker 12 against the action of accelerating spring 17.

When the

toggle elements

26 and 27 reach prop 33 in their upward movement under the action of piston 8 and ram 32, pin 30 biases prop 33 clockwise and slides on it until roller 31 reaches abutment 36. After pin 30 slides on prop 33, prop 33 rotates counterclockwise under the action of its biasing means 38 until it is in a position to support pin 30. Lever 41 and trip latch 43 retain roller 28 in position adjacent stop 37. The toggle formed by

elements

26 and 27 is retained in contact closed position by the combined action of prop 33, lever 41 and latch 43.

A closing operation is completed when prop 33, lever 41, and latch 43 have closed the contacts and locked the toggle elements in contact closed position. Then the supply of liquid under pressure may be automatically shut off. This may be achieved for instance, by a limit switch (not shown) controlled by pin 25 which deenergizes solenoid 95.

Upon the deenergization of the solenoid of actuating means 95 a spring 98 in actuating means 95 actuates the armature of actuating means 95 and valve element 66 to their extreme right position. Liquid under pressure from accumulator 50 then flows from inlet chamber 83 through orifice 72, pipe 97, orifice 84 to the upper end of cylinder 7 of motor 13, causing ram 32 and piston 8 to return to their bottom or lower position. As the ram 32 and piston 8 return to their lower position, liquid under piston 8 is expelled under high velocity by piston 8 through orifice 73, chamber 81, orifice 85, pipe 86 to reservoir 60. In accordance with the invention claimed the kinetic energy of the liquid expelled under high velocity of piston 8 of motor 13 through valve 64 aids the spring 98 of the solenoid actuating means in moving the valve element 66 to its extreme right position. Valve element 66 of valve 64 remains in the extreme right hand position when the solenoid of the actuating means 95 is deenergized. Reservoir 60 may be open to atmospheric pressure or closed and having an air cushion above the liquid level thus preventing a pressure buildup below piston 8 of motor 13 which otherwise might cause creeping of the piston 8 toward its upper position.

Energy expended during operation is replenished in the accumulator by the power driven pump 62 or the hand pump 61. The maximum and minimum system pressures are controlled by a pressure actuated motor switch (not shown).

The hand pump 61 used for emergency closing can also be used as a maintenance closing device. To close the breaker by hand the manual operating lover of the manual means 96 may latch the valve 64 in its left hand position. The hydraulic mechanism then acts as a simple hydraulic jack and the breaker can be jacked closed or to any intermediate position. Check valves within the hand pump lock the circuit breaker positively in any position, affording the maximum safety to inspection or maintenance personnel.

The hydraulic operating system oifers several important advantages to the user of power circuit breakers. Maintenance is reduced to a minimum by virtue of the few moving parts which are employed. All moving parts within the system are constantly immersed in a liquid having excellent lubricating; properties, therefore wear between sliding surfaces is minimized. The completely sealed system protects all internal surfaces from corrosive eifects of moisture and dirt. The small physical size of the hydraulic operating mechanism and its light weight make it easy to handle.

The hydraulic operating mechanism provides high speeds of operation when needed. Reclosing speeds far in excess of those presently required by circuit breaker standards are easily attainable.

The high efficiency of the hydraulic system has resulted in the reduction of the size of the motor required in the liquid supply unit. Compared to a pneumatic system of the same capacity, the motor required by the hydraulic system is much smaller. The pump up time from zero pressure to full operating pressure is about twenty-five percent of the time required on an air pressure system.

Tests indicated the ability of the hydraulic operating mechanism to obtain very high reclosing speeds. When coupled with a toggle linkage as shown, it is necessary that the ram 32 be rapidly retrieved from its upper position during repetitive reclosures of the breaker contacts. This is necessary to allow the mechanical trip free mechanism to reset quickly and permit the next reclosure. The return of ram 32 to its lower position was found to be controlled by the time necessary to shift valve elements 66 of control valve 64 from left to right. Thus by aiding the movement of valve element 66 of valve 64 with the exhaust liquid from motor 13 valve speeds have been increased resulting in high speed circuit breaker operation.

Although but two embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. A circuit interrupting device comprising a pair of relatively movable contacts, a motor comprising a cylinder and a piston for causing engagement of said contacts, valve means for admitting liquid under pressure to said cylinder and exhausting liquid being expelled under high velocity of said piston from said cylinder, said valve means controlling the actuation of said piston to close said contacts and comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, and a second orifice in said valve cylinder to direct exhaust liquid under pressure from said motor into said valve cylinder, actuating means connected to said valve element for causing liquid to move through said orifices, said valve element being formed to provide land surfaces separated by grooves, said grooves on the downstream sides of said orifices being shaped to direct a jet of liquid against said valve element to aid said actuating means to actuate said valve element, and a pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

2. A circuit interrupting device comprising a pair of relatively movable contacts, a double acting motor comprising a cylinder and a piston for causing relative movement of said contacts, valve means for admitting liquid under pressure to one end of said cylinder and exhausting a jet of liquid being expelled under high velocity by said piston from the other end of said cylinder, said valve means comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, and a second orifice in said valve cylinder to direct said jet of exhaust liquid from said motor into said valve cylinder, actuating means connected to saidvalve element for causing liquid to move through said orifices, said valve element beingformed to provide land surfaces separated by grooves, said grooves on the downstream sides of saidorifices' being shaped to direct a jet of liquid against said valve element to aid said actuating means to actuate said valve element, and a pneumohydraulic accumulator for supplying liquid under pressure to said valve means.

3. in combination a double acting motor comprising a cylinder and a piston for causing relative movement of a pair of contacts, valve means for admitting liquid under pressure to one end of said. cylinder and exhausting a jet of liquid being expelled under high velocity of said piston from the other end of said cylinder, said valve 1 "ising a valve cylinder, a valve element, a first or es in said valve cylinder for directing liquid under pressure to said motor, and a second orifice in said valve cylinder to direct said jet of exhaust liquid from said motor into said valve cylinder, means connected to said valve element for actuating said valve element to cause liquid to move through said orifices, said valve element being formed to provide land surfaces separated by grooves, said grooves being shaped to provide a relatively steep upstream slope and a relatively fiat downstream slope to direct the jet of liquid through said second orifice against said valve element to aid said actuating means to actuate said valve element, and a pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

4-. in an operating mechanism for circuit breakers a double acting motor comprising a cylinder and a piston for causing relative movement of a pair of contacts, valve means for admitting liquid under pressure to one end of said cylinder and exhausting a jet of liquid being expelled under high velocity of said piston from the other end of said cylinder, said valve means comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, and a second orifice in said valve cylinder to direct said jet or". exhaust liquid under pressure from said motor into said valve cylinder, electrical means connected to said valve element for actuating said valve element to cause liquid to move through said orifices, said valve element being formed to provide land surfaces separated by grooves, at least one of said grooves on the downstream sides of said orifices being shaped to direct a jet of liquid against said valve element to aid said actuating means to actuate said valve element, and a pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

5. in an operating mechanism for circuit breakers a double acting motor comprising a cylinder and a piston for causing relative movement of a pair of contacts, valve means for admitting liquid under pressure to one end of said cylinder and exhausting a jet of liquid being expelled under high velocity of said piston from the other end of said cylinder, said valve means comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, and a second orifice in said valve cylinder to direct said jet of exhaust liquid under pressure from said motor into said valve cylinder, solenoid means directly connected to said valve element for actuating said valve element to cause jets of liquid to move through said orifices, said valve element and said-valve cylinder being grooved to form a chamber downstream of said second orifice, said groove in said valve element being shaped to provide a relatively steep upstream slope and a relatively flat downstream slope to direct the jet of liquid through said second orifice against said valve element, said chamber utilizing the turbulence caused by the direction of said jet of liquid against said valve element to aid said actuating means to actuate said valve element, and a pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

6. A circuit interrupting device comprising a pair of relatively movable contacts, a double acting motor comprising a cylinder and a piston for causing relative movement of said contacts, valve means for admitting liquid underpressure to one end of said cylinder and exhausting a jet' of liquid-being expelled under high velocity of said piston from the other end of said cylinder, said valve means comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure tosaid motor, and a second orifice in said valve cylinder to direct said jet of exhaust liquid under pressure from said motor into said valve cylinder, electrical means directly connected to said valve element for actuating said valve element to cause liquid to move through said orifices, said valve element and said valve cylinder provided with grooves to form a chamber downstream of said second orifice, said groove in said valve element being shaped to provide a relatively steep upstream slope and a relatively flat downstream slope, saidgroove in said valve cylinder being shaped to direct the jet of liquid from said second orifice having passed over said sloped surfaces of said valve element against said valve element, said chamber utilizing the turbulence caused by the direction of said jet of liquid against said valve element to aid said actuating means to actuate said valve element, and a pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

7. A circuit interrupting device comprising a pair of relatively movable contacts, a double acting motor comprising a cylinder and a piston for causing relative movement of said contacts, valve means for admitting liquid under pressure to one end of said cylinder and exhausting a jet of liquid being expelled under high velocity of said piston from the other end of said cylinder, said valve means comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, a second orifice in said valve cylinder to direct said jet of exhaust liquid under pressure from said motor into said valve cylinder, solenoid means mechanically connected to said valve element for actuating said ,valve element to cause liquid to move through said orifices, said valve element and said valve cylinder provided with grooves to form a chamber downstream of said second orifice, said groove in said valve element being shaped to provide a relatively steep upstream slope and a relatively flat downstream slope, said groove in said valve cylinder being shaped to direct the turbulent part of the jet of liquid from said second orifice having passed over said sloped surfaces of said valve element away from said relatively flat slope of said valve element to aid said actuating means to actuate said valve element, and a pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

8. A circuit interrupting device comprising a pair of relatively movable contacts, a double acting motor comprising a cylinder and a piston for causing relative movement of said contacts, valve means for admitting liquid under pressure to one end of said cylinder and exhausting a jet of liquid being expelled under high velocity of said piston from the other end of said cylinder, said valve means comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, a second orifice in said valve cylinder to direct said jet of exhaust liquid under pressure from said motor into said valve cylinder, solenoid means connected to said valve element for actuating said valve element to cause jets of liquid to move through said orifices, said valve element and said valve cylinder provided with grooves to form a chamber downstream of said second orifice, said groove in said valve element being shaped to provide a relatively steep upstream slope and a relatively fiat downstream slope, said groove in said valve cylinder being shaped to direct the turbulent part of the jet of liquid from said second orifice having passed over said slope surfaces of said valve element toward said relatively steep slope of said valve element to aid said actuating means to actuate said valve element, and pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

9. In an operating mechanism for circuit breakers a double acting motor compriisng a cylinder and a piston for causing relative movement of a pair of contacts, valve means for admitting liquid under pressure to one end of said cylinder and exhau'sting a jet of liquid being expelled under high velocity of said piston from the other end of said cylinder, said valve means comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, a second orifice in said valve cylinder to direct said jet of exhaust liquid under pressure from said motor into said valve cylinder, solenoid means mechanically connected to said valve element for actuating said valve element to cause jets of liquid to move through said orifices, said valve element and said valve cylinder provided with grooves to form a chamber downstream of said second orifice, said groove in said valve element being shaped to provide a relatively steep upstream slope and a relatively fiat downstream slope, said groove in said valve cylinder being shaped to direct the turbulent part of the jet of liquid from said second orifice having passed over said sloped surfaces of said valve element away from said relatively fiat slope of said valve element against said relatively steep slope of said valve element to aid said actuating means to actuate said valve element, and a pneumohydraulic accumulator for supplying liquid under pressure to said valve means.

10. A circuit interrupting device comprising a pair of relatively movable contacts, a double acting motor comprising a cylinder and a piston for causing relative movement of said contacts, a collapsible linkage of the trip free type for operatively relating the breaker to said motor, tripping means for causing collapse of said linkage to cause opening of said contacts, a ram on said piston separate from said linkage and cooperating therewith upon collapse thereof for reclosing said contacts, valve means for admittting liquid under pressure to one end of said cylinder and exhausting a jet of liquid being expelled under high velocity of said piston from the other end of said cylinder, said valve means comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, a second orifice in said valve cylinder to direct said jet of exhaust liquid from said motor into said valve cylinder, solenoid actuating means connected to said valve element for causing liquid to move through said orifices, said valve element being formed to provide land surfaces separated by grooves, said grooves on the downstream sides of said orifices being shaped to direct a jet of liquid against said valve element to aid said actuating means to actuate said valve element, and a pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

11. A circuit interrupting device comprising a pair of relatively movable contacts, a double acting motor comprising a cylinder and a piston for causing relative movement of said contacts, a collapsible linkage of the trip free type for operatively relating the breaker to said motor, tripping means for causing collapse of said linkage to cause opening of said contacts, a ram on said piston separate from said linkage and cooperating therewith upon collapse thereof for reclosing said contacts, valve means for admitting liquid under pressure to one end or said cylinder and exhausting a jet of liquid being expelled under high velocity of said piston from the other end of said cylinder, said valve means comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, a second orifice in said valve cylinder to direct said jet of exhaust liquid from said motor into said valve cylinder, solenoid means mechanically connected to said valve element for actuating said valve element to cause liquid to move through said orifices, said valve element being formed to provide land surfaces separated by grooves, said grooves being shaped to provide a relatively steep upstream slope and a relatively fiat downstream slope to direct the jet of liquid through said second orifice against said valve element to aid said actuating means to actuate said valve element, and a pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

12. A circuit interrupting device comprising a pair of relatively movable contacts, a double acting motor comprising a cylinder and a piston for causing relative movement of said contacts, a collapsible linkage of the trip free type for operatively relating the breaker to said' motor, tripping means for causing collapse of said linkage to cause opening of said contacts, a ram on said piston separate from said linkage and cooperating therewith upon collapse thereof for reclosing said contacts, valve means for admitting liquid under pressure to one end of said cylinder and exhausting a jet of liquid being expelled under high velocity of said piston from the other end of said cylinder, said valve means comprising a valve cylinder, a valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, a second orifice in said valve cylinder to direct saidjet of exhaust liquid under pressure from said motor into said valve cylinder, solenoid means mechanically connected to said valve element for actuating saidvalve element to cause liquid to move through said orifices, said valve element and said valve cylinder provided with grooves to form a chamber downstream of said second orifice, said groove in said valve element being shaped to provide a relatively steep upstream slope and a relatively flat downstream slope, said groove in said valve cylinder being shaped to direct the turbulent part of the jet of liquid from said second orifice having passed over said sloped surfaces of said valve element away from said relatively fiat slope of said valve element to aid said actuating means to actuate said valve element, and a pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

13. A circuit interrupting device comprising a pair of relatively movable contacts, a double acting motor comprising a cylinder and a piston for causing relative movement of said contacts, a collapsible linkage of the trip free type for operatively relating the breaker to said motor, tripping means for causing collapse of said linkage to cause opening of said contacts, a ram on said piston separate from said linkage and cooperating therewith upon collapse thereof for reclosing said contacts, valve means for admitting liquid under pressure to one end of said cylinder and exhausting a jet of liquid being expelled under high velocity of said piston from the other end of said cylinder, said valve means comprising a valve cylinder, 21 valve element, a first orifice in said valve cylinder for directing liquid under pressure to said motor, and a second orifice in said valve cylinder to direct said jet of exhaust liquid under pressure from said motor into said valve cylinder, solenoid means mechanically connected to said valve element for actuating said valve element to cause liquid to move through said orifices, said valve element and said valve cylinder provided with grooves to form a chamber downstream of said second orifice, said groove in said valve element being shaped to provide a relatively steep upstream slope and a relatively flat downstream slope, said groove in said valve cylinder being shaped to direct the turbulent part of the jet of liquid from said second orifice having passed over said sloped surfaces of said valve element away from said relatively fiat slope of said valve element against said relatively steep slope of said valve element to aid said actuating means to actuate said valve element, and a pneumo-hydraulic accumulator for supplying liquid under pressure to said valve means.

References Cited in the file of this patent UNITED STATES PATENTS 2,214,816 Harrington Sept. 17, 1940 2,290,479 Mercier July 21, 1942 2,392,471 Fox .Tan. 8, 1946 2,578,204 Peek Dec. 11, 1951 2,607,321 Lado Aug. 19, 1952 2,621,676 Loft Dec. 16, 1952