US2730590A - Fluid motor dumping system with fluid admitting and venting valve - Google Patents

Description

Jan. 10, 1956 A. c. KELLE 2,730,590

FLUID MOTOR DUMPING SYSTEM WITH FLUID ADMITTING AND VENTING VALVE Filed March 2, 1953 2 Sheets-Sheet l J OUR C E OF F1. 0/0 UNDER P2555025 Q vwMWo/v W 2. 3 i 0. 0%

Jan. 10, 1956 A. c. KELLE FLUID MOTOR DUMPING SYSTEM WITH FLUID ADMITTING AND VENTING VALVE 2 Sheets-Sheet 2 Filed March 2, 1953 rlifllilll souecE 0F 9 a M, a g g 0 7 m w I a fl 0 w m M. 1* 4 g 3 a m fi United States Patent FLUID MOTGR DUMPING SYSTEM WITH FLUHD ADMITTHNG AND VENTENG VALVE Arthur C. Kellie, Stoughton, Mass assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis.

Application March 2, 1953, Serial No. 339,815

12 Claims. (Cl. mill-82) This invention relates to circuit breakers and more particularly to pneumatically operated high speed circuit breakers.

One of the problems existing in the prior art which limited the speed of operation of a pneumatically operated circuit breaker was the excessive time needed to reclose the circuit breaker contacts. Part of the time delay in closing the contacts of the circuit breaker was due to the slow acting air dumping means used to exhaust the air under pressure in the cylinder of the contact actuating fluid motor.

In order to reduce the time needed to reclose the arcing contacts, a new and improved fluid operated mechanism is provided comprising a fluid motor for closing a pair of arcing contacts, means for admitting fluid under pressure from a source to the cylinder, and dumping means for venting the cylinder to atmosphere or to a low pressure region to cause the piston to return to its initial position. The dumping or venting means prevents the fluid admitting means from supplying fluid under pressure to the cylinder of the fluid motor during a venting operation so as to limit to a minimum the amount of fluid that the venting means must dispose of.

It is therefore one object of the present invention to provide a new and improved pneumatic circuit breaker operating system capable of effecting high speedopening and reclosing of the circuit breaker.

Another object of this invention is to provide a new and improved pneumatic circuit breaker operating system of the cylinder and piston type in which the exhaust gases are dumped in a manner which permits rapid piston reversal action.

A further object of this invention is to provide a new and improved pneumatically operated trip free operating system for a circuit breaker in which the gas admitting action and the dumping action of the operating mechanism is controlled by an element indicative of the relative completeness of the closing operation of the trip free mechanism.

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

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

Fig. 2 is a view in section of a modification of the circuit breaker operating mechanism illustrated in Fig. 1;

Fig. 3 is a view in section of another modification of the circuit breaker operating mechanism ilustrated in Fig. 1; and

Fig. 4 is a side elevation in section of a modification of the dual purpose valve illustrated in Fig. 2.

Referring more particularly to the drawings by charac-v ters of reference, Fig. 1 illustrates a pneumatically operated trip free mechanism 11 for a circuit breaker 12. The pneumatically operated trip free mechanism 11 comprises a pneumatic motor 13 of the cylinder and piston "ice 2 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 2%. Lever 1% is connected to the trip free operating linkage M by means of operating rod 21.

The operating linkage l i comprises a lever 22 pivoted at 23 and a lever 24 pivoted at 26. 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 3t Pin 30 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 36 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 36. In the closed position of the circuit breaker 12, pin 34 forming the joint or connection between toggle elements 26 and 27 is supported by a spring biased prop 33. Spring 34 is secured at one end on the frame of the trip free operating mechanism 111 and at the other end to a lug 35 of toggle element 2'7.

The circuit breaker 12 is tripped by spring 17 upon a predetermined movement of a tripping mechanism 40, Tripping mechanism til comprises a first lever 41 pivoted at 4-2, a second lever pivoted at M, and a trip solenoid 45 comprising a plunger 46 adapted to act on lever 43. Plunger 46 can be operated either electromagnetically by energizing solenoid 4-5 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 ii 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 rotation counterclockwise of lever 43. 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 l5, 16.

In order to close the circuit breaker compressed gas is admitted to fluid motor 13 through a pipe 5% solenoid control valve 51, a cutofl vaive 92, and a venting means or dump valve 53 comprising castings 54 and 55. Motor 1.: comprises a cylinder 57 and a piston 53 which is biased downwardly by a spring means 5% resting against the bottom of cylinder head 49 of cylinder 57. Spring means 59 returns the piston to its initial position shown in Fig. 1 upon closing of the circuit breaker 12. Piston 58 is provided with a stepped abutment surface Stl. The cylinder head 45 is mounted in the downstream end of cylinder 5'7 and is provided with abutment surfaces 82 and 33 adapted to cooperate with abutment surfaces 8 3, 81 on piston 58. A felt cushion 84 is arranged between cylinder head 4% and a top piate 85 for receiving the shock transmitted to cylinder head 49 upon impact thereon of piston 53. Piston 53 is connected to ram 32 which coacts with roller 31 of linkage mechanism 14 to close the circuit breaker contacts 15, 16.

Casting 54 defines an intake passage 6%. Casting 55 defines a discharge ring providing a plurality of exhaust passages 62, separated by spacers 63. Bolts 64 passing Castings 54, 55 provide the housingfor dump valve 53. Dump valve 53 further comprises a plate or element 67 biased by aspring 63 in the upward direction against valve seats 69 and 79 defined by casting 55. Plate 67 is provided with perforations 71 adapted to be closed by a second nonperforated plate 72 arranged on the downstream side of plate 67, which faces piston 58. Plate 72 is biased by springs 73 against plate 67 and permits gas under pressure to flow upward only through perforation 71. The travel of plate 72 in upward direction is limited by abutments '74.

Motor 13 is controlled by the high speed solenoid actuated control valve 51 and a dual purpose valve structure 52 which is responsive to the flow of gas through the control valve 51. Valve structure 52 comprises a cylinder 90, a valve stem 91, cutofi valve element 92, a venting valve element 93, biasing spring 94-, inlet port 95 and outlet ports 96 and 97. Valve stem 91 is actuated to close inlet port 95 and to open outlet ports 96 and 97 by lever 22 and a push rod 116 during a circuit breaker closing operation. The valve structure 52 employs a cylinder 99 which houses both the cutoff valve element 92 and the venting valve element 93, or the valve elements may be housed in separate unattached cylinders; valve structure 52 is more economical to manufacture than two separate valves and also reduces the number of moving parts.

The circuit breaker system in Fig. l of the drawings is shown with the contacts 15 and 16 in the closed circuit position and the tripping mechanism in the corresponding position. Upon the energization of trip solenoid 45, plunger 3-6 actuates lever 43 counterclockwise about point id. After a predetermined movement of lever 43, lever 41 is released to rotate counterclockwise about point 4-2 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 11, 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.

As the arcing contacts 15 and 16 are being separated rod 21 actuates lever 22 counterclockwise, thereby causing spring 94 to move valve stem 91 and valve elements 92 and 93 upward. With valve structure 52 in contact open position gas under pressure may flow upon subsequent opening of valve 51 from valve 51 through inlet port 95 of valve structure 52 through cylinder 90, outlet port 96, passage 60 to cylinder 57 of motor 13. Valve element 93 of valve structure 52 closes outlet port 97 when valve structure 52 is in contact open 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 valve 51 is energized to permit gas under pressure to flow from a reservoir (not shown) through pipe 53, control valve 51, valve structure 52, passage 63 into a chamber 98 formed by castings 54, 55 on the upstream side of plate 67. When the pressure in chamber 93 reaches a predetermined value, plate 72 is lifted from plate 67 against the bias of springs 73. The movement of plate 72 upward opens ports 71 to permit compressed air to enter cylinder 57 and to move piston 53 and ram 52 upward. The closing force of motor 13 is applied to linkage 14- by engagement of ran". 32 and roller 31. Toggle elements 26 and 27 in moving upward during a closing stroke of piston 58, rotate lever 22 about its pivot point 23 in the clockwise 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 58 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 34- 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 compressed gas may be automatically shut off. This is achieved by the downward movement of rod 116 and stem 91 and valve elements 92 and 93. Push rod 116 and stem 91 are actuated downward upon the clockwise rotation of lever 22 during the contact closing operation. The downward movement of push rod 116, stem 91 and valve elements 92 and cause the valve structure 52 to shut oil the closing air from control valve 51 and substantially simultaneously opens chamber 98 to atmosphere. The gas confined in chamber 93 then passes through pipe 60, port 96, cylinder 90 and port, 97 of valve structure 52 to atmosphere. On the downward movement of piston 53 of motor 13 the gas below piston 58 will also flow to atmosphere through dumping valve 53. Plate 67 is forced downward against its biasing spring 68 during the downward movement of piston 58 thereby connecting the lower end of cylinder 57 to atmosphere through exhaust passages 62. This venting action causes the spring means 59 to return the piston 58 to its initial position, shown in Fig. 1.

With chamber 98 kept to a minimum volume, a relatively small outlet port 9'7 rapidly reduces the pressure in chamber 98 to atmosphere. Control valve 51 is a high speed solenoid operated type of valve, the resetting time of which depends upon the differential pressure acting on its valve element 75. Therefore, after the electric circuit energizing coil 76 of valve 51 is opened, the valve element 75 resets to closed position at a rate depending upon the back pressure built up in pipe 77 which connects control valve 51 and valve structure 52.

Fig. 2 partially illustrates a modification of the motor operating mechanism shown in Fig. 1 wherein the push rod 116 of Fig. 1 is removed and valve structure :52 is actuated pneumatically by a means 115 comprising a'pipe and orifice 101 in cylinder 57 and an orifice 102 arranged in the head of cylinder 90 of valve structure 52.

Valve structure '52 closes ofi pipe 77 during a contact closing operation when piston 58 has moved past orifice 101 in its upward travel. When piston 58 of motor 13 uncovers orifice 101 toward the end of its circuit breaker closing stroke, compressed gas from cylinder 57 flows through orifice 101, pipe 100, orifice 102 and into cylinder 90 depressing valve elements 92 and 93 against the bias of spring 94. This movement of valve elements 92 and 93 substantially simultaneously eifects closing of pipe 72 and opening of outlet ports 96 and 97, thereby permitting compressed gas in chamber 98 to enter through port 96 into that portion of cylinder 90 confined between valve elements 92 and 93 and through port 97 to atmosphere. It is possible, with the location of the ports 96 and 97, as shown in Fig. 2, to obtain a slightly greater pressure downward than upward on valve elements 92 and 93 due to the downward direction of flow of gas which tends to reduce the pressure on the underside of valve element 92 and also tends .to increase the pressure on the top side of valve element '93.

During the downward movement of piston 58 of motor 13 after piston 58 passes orifice 101 the gas under pressure above valve element 92 of valve structure 52 will pass to atmosphere through permanently open vent holes N3.

Fig. 3 illustrates a modification of the cylinder structure of motor 13 wherein the dump valve 53 is omitted and all the gas under pressure below piston 58 is vented to atmosphere through valve structure 52.

Fig. 4- illustrates a valve structure 105 which is a modification of the valve structure 52 shown in Figs. 2 and 3. Valve structure 105 comprises a cylinder 1%, a valve stem 107 and valve elements and 109. The valve element 10% and the upper portion 110 of valve element ill? have the same diameter, while the lower portion 111 of valve element 199 is of enlarged diameter. A plurality of small communicating passages 112 extending from the chamber above the lower Valve element M9 to the chamber 14 above the enlarged portion thereof, are so positioned as to be opened at a predetermined position of the valve elements 108 and 109 in their downward movement, thereby permitting compressed gas to discharge into the chamber 114 above the enlarged portion 111 of valve element 109 to create a positive downward bias. Valve structure 165 will provide a greater time delay action than the valve structure 52 shown in Figs. 2 and 3 to upward movement of its valve elements.

Although but a few 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. In combination, a circuit breaker comprising a pair of engageable arcing contacts, a motor operable by fluid under pressure and comprising a cylinder and a piston movably arranged therein for causing relative movement of said contacts, a source of fluid under pressure, means for admitting fluid under pressure from said source to one end of said cylinder to close said contacts, and means for venting said cylinder to atmosphere to cause said piston to return to its initial position, and substantially simultaneously therewith preventing said fluid admitting means from supplying fluid to said cylinder during said venting operation.

2. In combination, a circuit breaker comprising a pair of engageable arcing contacts, a motor operable by fluid under pressure and comprising a cylinder and a piston movably arranged therein for causing relative movement of said contacts, a source of fluid under pressure, means for admitting fluid under pressure from said source to one end of said cylinder to close said contacts, means for returning said piston to the initial position thereof upon closing of the breaker, means for venting said cylinder to atmosphere to cause said piston to return to its initial position, and means for preventing said fluid admitting means from supplying fluid to said cylinder during said venting operation.

3. In combination, a circuit breaker comprising a pair of engageable arcing contacts, a motor operable by gas under pressure and comprising a cylinder and a piston movably arranged therein for causing relative movement of said contacts, a source of gas under pressure, means for admitting gas under pressure from said source to one end of said cylinder to close said contacts, means for venting said cylinder to atmosphere to cause said piston to return to its initial position, and means for controlling the admission of gas under pressure to said cylinder during breaker closing operations and during cylinder venting operations.

4. In combination, a circuit breaker comprising a-pair of engageable arcing contacts, a motor operable by gas under pressure and comprising a cylinder and a piston movably arranged therein for causing relative movement of said contacts, a source of gas under pressure, means for admitting gas under pressure from said source to one end of said cylinder to close said contacts, means for vent- 6 ing said cylinder to atmosphere to causev said piston to return to its initial position, and means for actuating said venting means and for preventing said gas admitting means from supplying gas to said cylinder upon said piston reaching a predetermined point during its movement in breaker closing direction.

5. In combination, a circuit breaker comprising a pair of engageable arcing contacts, a motor operable by gas under pressure and comprising a cylinder and a piston movably arranged therein for causing relative movement of said contacts, a source of gas under pressure, a valve structure for controlling the supply of gas under pressure to said cylinder to cause actuation of said piston, said valve structure comprising a cutofi? valve element and a venting valve element, and means for actuating said valve structure, said cutofl valve element arranged to admit gas under pressure to said cylinder to cause engagement of said contacts, said valve structure upon actuation thereof during a breaker closing operation causing said venting element to vent said cylinder to atmosphere and cause said cutoff valve element to prevent gas from flowing to said cylinder during the venting operation.

6. In combination, a circuit breaker comprising a pair of engageable arcing contacts, a motor operable by gas under pressure and comprising a cylinder and a piston movably arranged therein for causing relative movement of said contacts, a source of gas under pressure, a valve structure for controlling the supply of gas under pressure to said cylinder to cause actuation of said piston, said valve structure comprising a cutoff valve element and a venting valve element, and means for actuating said valve structure, said cutoff valve element arranged to admit gas under pressure to said cylinder to cause engagement of said contacts, said valve structure upon said piston reaching a predetermined point in its travel in breaker closing direction actuated by said valve actuating means to cause said venting element to vent said cylinder to atmosphere and substantially simultaneously therewith cause said cutoff valve element to prevent gas from flowing to said cylinder during the venting operation.

7. In combination, a circuit breaker comprising a pair of engageable arcing contacts, a motor operable by gas under pressure and comprising a cylinder and a piston movably arranged therein for causing relative movement of said contacts, source of gas under pressure, a control valve for controlling the supply of gas under pressure to said cylinder to cause actuation of said piston, a dual purpose valve structure responsive to the flow of gas through said controi valve, said valve structure comprising a cutoff valve element and a venting valve element, and means for actuating said valve structure, said piston upon reaching a predetermined point during its movement in breaker closing direction causing actuation of said valve structure actuating means to cause said cutoff valve element to stop the flow or gas from said control valve to said cylinder and substantially simultaneously therewith to cause said venting element to vent said cylinder to atmosphere.

8. in combination, a circuit breaker comprising a pair of engageable arcing contacts, a motor operable by gas under pressure and comprising a cylinder and a piston movably arranged therein for causing reiative movement of said contacts, a source of gas under pressure, a valve structure for controlling the supply of gas under pressure to said cylinder to cause actuation of said piston, said valve structure comprising a cutoff valve element and a venting valve element, and pneumatic means for actuating said valve structure, said cutoff valve eiernent arranged to admit gas under pressure to said cylinder to cause engagement of said contacts, said valve structure upon actuation thereof by said pneumatic means during a breaker closing operation causing said venting element to vent said cylinder to atmosphere and cause said cutoif valve to prevent gas from flowing to said cylinder during the venting operation.

9. In combination, a circuit breaker comprising a pair of engageable arcing contacts, a motor operable by gas under pressure and comprising a cylinder and a piston movably arranged therein for causing relative movement of said contacts, a source of gas under pressure, a valve structure for controlling the supply of gas under pressure to said cylinder to cause actuation of said piston, said valve structure comprising a cutoii valve element and a venting valve element, pneumatic means comprising a pipe connection between said cylinder and said valve structure controlled by said piston, said cutoff valve element arranged to admit gas under pressure to said cylinder to cause engagement of said contacts, said valve structure upon actuation thereof during a breaker clos ing operation causing said venting element to vent said cylinder to atmosphere and cause said cutofl valve to prevent gas from flowing to said cylinder during the venting operation.

10. In combination, a circuit breaker comprising a pair of engageable arcing contacts, a motor operable by gas under pressure and comprising a cylinder and a piston movably arranged therein for causing relative movement of said contacts, a source of gas under pressure, a control valve for controlling the supply of gas under pressure to said cylinder to cause actuation of said piston, a cutoff valve, a venting valve, and mechanical means for actuating said cutoff valve and said venting valve in response to said piston reaching a certain point during its travel in breaker closing direction, said mechanical means causing said venting valve to vent said cylinder and said cutofi valve to prevent gas from flowing to said cylinder during said venting operation.

11. In combination, a circuit breaker comprising a pair of relatively movable contacts, a motor comprising a cylinder and a piston for causing relative movement of said contacts, a source of gas under pressure, a valve structure comprising a cutoff valve element and a venting valve element, pneumatic means for actuating said valve structure in response to a predetermined position of said piston, valve structure for controlling the supply of gas under pressure to said cylinder to cause actuation of said piston, spring means for returning said piston to the initial position thereof upon closing of the breaker, 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 the breaker, a ram on said piston separate from said linkage and cooperating therewith upon collapse thereof for reclosing the breaker, said valve structure upon actuation thereof causing said venting valve element to vent said cylinder and to cause said spring means to rapidly return said piston to said initial position, and causing said cutoff valve element to stop the supply of gas from flowing to said cylinder during said venting operation.

12. In combination, a circuit breaker comprising a pair of engageable arcing contacts, a motor operable by gas under pressure and comprising a cylinder and a piston movably arranged therein for causing relative movement or" said contacts, a source of gas under pressure, means for admitting gas under pressure from said source to one end of said cylinder to close 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 the breaker, a ram on said'piston separate from said linkage and cooperating therewith upon collapse thereof for reclosing the breaker, and means for substantially venting simultaneously said cylinder to atmosphere to cause said piston to return to its initial. position and stopping said gas admitting means from supplying gas to said cylinder during said venting operation.

References Cited in the tile of this patent UNITED STATES PATENTS 2,548,221 Kelle Apr. 10, 1951 2,578,204 Peek Dec. 11, 1951 2,578,349 Goodwin Dec. 11, 1951

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