US3688799A

US3688799A - Pilot actuated fluid control valve

Info

Publication number: US3688799A
Application number: US47666A
Authority: US
Inventors: Alan Donald Bunyard
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-06-21
Filing date: 1970-06-19
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: BE752251A; NL165260B; DE2030881A1; IL34753A0; DE2030881C3; FR2047020A1; DE2030881B2; NL7008961A; FR2047020B1; NL165260C; JPS496403B1

Abstract

A direction-control valve in which a poppet valve is caused to perform reciprocating movements under the influence of fluid pressure which is regulated, as regards its application to said poppet valve, by the positioning of a second valve. In one operative position of said second valve, a first exhaust port is closed by a first port closure means which moves in response to a fluid-pressure-drop thereacross in order to permit the supply of fluid under super-atmospheric pressure to one side of a doubleacting cylinder, and a second exhaust port is opened by a second port closure means which moves in response to a fluid-pressuredrop thereacross in order to permit the exhaust of used pressurized fluid from the other side of said double-acting cylinder. In the other operative position of said second valve, the opening and closure of the first and second exhaust ports are reversed.

Description

United States Patent Bunyard 1 Sept. 5, 1972 [54] PILOT ACTUATED FLUID CONTROL VALVE [72] Inventor: AlanDonald Bunyard, Burrell Road,

Haywards Heath, Sussex, England [22] Filed: June 19, 1970 [21] Appl. No.: 47,666

[30] Foreign Application Priority Data June 21, 1969 Great Britain ..3l,453/69 July 5, 1969 Great Britain ..33,993/69 [52] US. Cl ..137/625.64 [51] Int. Cl. ..Fl6r 11/02 [58] Field of Search....137/l02, 106, 625.63, 625.64, 137/596.14, 596.15, 596.16

[56] References Cited UNITED STATES PATENTS 2,567,391 9/1951 Mead ..137/102 2,898,936 8/1959 Collins ..137/625.63 3,411,409 11/1968 Bunyard ..91/1

FOREIGN PATENTS OR APPLICATIONS 1,031,887 3/1953 France .Q ..137/102 Primary Examiner-Henry T. Klinksiek Attomey-Berman, Davidson and Berman ABSTRACT A direction-control valve in which a poppet valve is caused to perform reciprocating movements under the influence of fluid pressure which is regulated, as regards its application to said poppet valve, by the positioning of a second valve. In one operative position of said second valve, a first exhaust port is closed by a first port closure means which moves in response to a fluid-pressure-drop thereacross in order to permit the supply of fluid under super-atmospheric pressure to one side of a double-acting cylinder, and a second exhaust port is opened by a second port closure means which moves in response to a fluid-pressure-drop thereacross in order to permit the exhaust of used pressurized fluid from the other side of said doubleacting cylinder. In the other operative position of said second valve, the opening and closure of the first and second exhaust ports are reversed.

12 Claims, 5 Drawing Figures PILOT ACTUATED FLUID CONTROL VALVE This invention relates to valves.

As employed herein, the term double-acting cylinder is intended to include the pistons of a rotary actuator which are axially displaceable along the cylinder towards or away from one another.

The present invention consists in a direction-control valve operable to provide control. and operation of a double-acting cylinder and having a reciprocatable poppet valve and another valve means, the arrangement being such that, if said direction-control valve were to be connected both to a double-acting cylinder and to a supply of fluid at super-atmospheric pressure, actuation of said other valve means to cause or to permit diversion of the flow of said fluid from one cylinder port to another would be followed by actuation of said poppet valve by said fluid whereby said one cylinder port would be placed in communication with an open exhaust port for the exhaust of used fluid to atmosphere.

In one embodiment of the invention, the directioncontrol valve is a four-way five port valve having two cylinder ports, two exhaust ports and an inlet port, said diversion of the flow of said fluid further causing closure by a first port closure means of the open one of said exhaust ports due to a pressure differential across said first port closure means, the other closed exhaust port being opened under the influence of a fluid pressure differential across a second port closure means associated with said other exhaust port. Said first and second port closure means may be cup valves.

Preferably, said other valve means is a solenoid-poppet valve. In one arrangement employing said solenoidpoppet valve, said reciprocatable poppet and said solenoid poppet valve are coaxially arranged, said diversion of the flow of said fluid being caused or permitted upon solenoid energization by movement of the plunger of said solenoid-poppet valve in a first direction of movement and said plunger movement being followed by movement of said reciprocatable poppet valve in said first direction of movement. De-energization of said solenoid would result in movement of the plunger under the influence of a spring in a second direction of movement which is the opposite of said first direction of movement, said plunger movement being followed by movement of said reciprocatable poppet valve by said fluid in said second direction of movement.

The pressure differentials across the first and second port closure means are created by two additional exhaust ports of which one, when open, connects to atmosphere that side of said second port closure means which is remote from said one cylinder port whereby the pressure of the used fluid in said double-acting cylinder opens said other exhaust port, and of which the other when said one is open is closed by virtue of the pressure on one side of said first port closure means being atmospheric and the pressure on the other side of said first port closure means being super-atmospheric, and vice versa.

Said reciprocatable poppet valve is preferably carried by a stern and in the vicinity of one end of said stem, said stem having in the vicinity of the other end thereof a seat containing an O-ring which seals against the inner surface of a right cylindrical cup made of a material having a low coefficient of friction, said stern extending through an aperture in the bottom wall of said cup and said one end of said stem being located outside the confines of said cup and said other end thereof being located within the confines of said cup, the movements of said reciprocatable poppet valve under the influence of said fluid at super-atmospheric pressure causing said poppet valve to seal two orifices alternately to effect alternate opening and closure of said other exhaust port by said second port closure means.

The present invention will now be more particularly described with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic plan view of an end cap of a rotary actuator of the construction illustrated in U.S. Pat. Nos. 3,411,409 and 3,537,358, issued to the inventor of the present invention;

FIG. 2 illustrates a sectional elevation on the line 11- II in FIG. 1, a solenoid having been shown in chain lines thereon;

FIG. 3 illustrates a sectional elevation on the line III-III in FIG. 1, without the solenoid outline in chain line but including a part of the solenoid plunger; and

FIGS. 4 and 5 illustrate views similar to those in FIGS. 2 and 3 and showing a modification of parts of the arrangement shown in FIGS. 2 and 3.

Referring to the drawings, there is illustrated an end cap 10 of the actuator having two circular cavities 11 each of which is placed in communication with an exhaust port by a cylinder port, one exhaust port being indicated by the reference numeral 12, the other exhaust port being indicated by the reference numeral 13, one cylinder port being indicated by the reference numeral 14 and the other cylinder port being indicated by the reference numeral 15.

A chamber 16 is formed in the end cap 10 which is in communication with said other exhaust port 13 by way of a passageway 17 which extends radially of the end cap. Said chamber 16 is also in communication with a chamber 18 by way of an axially extending passageway 19 which extends as far as a valve seat 20. One axially extending passageway 21 (FIG. 2) and a short radially extending passageway 22 connect the chamber 18 and the said one exhaust port 12 to one another. Another axially extending passageway 23 (FIG. 3) and another short radially extending passageway 24 connect the chamber 18 and the chamber 16 to one another. Further, a radially extending passageway 25 connects the passageway 19 to a screw-threaded socket 26 into which the threaded male end of a hose (not shown) is intended to be screwed, said hose being connected to a supply of fluid (for example air) at super-atmospheric pressure.

A cup 27 made of a synthetic resin material having a low coefficient of friction (for example P.T.F.E. possibly reinforced or filled for strength) is placed in one part of the chamber 16 and has an aperture therein which is concentric with the chamber 16. A reciprocatable poppet valve 28 has a stem 29 which carries a square-section ring 30 in a groove-therefor at or in the vicinity of one end of said stem and which is appropriately formed at or in the vicinity of the other end thereof with another seat or groove in which there is positioned an O-ring 31. A radially extending hole is provided in the wall of the cup so as to be in register with a radially extending passageway 32 whereby there is a direct exhaust to atmosphere for the purpose hereinafter described.

A solenoid 33 has a sleeve 34 which has a screwthreaded end 35 which is screwed into the end cap against a sealing ring 36. The solenoid plunger 37 carries

seals

38, 39 at its opposite ends and thus constitutes a solenoid-poppet valve. Said plunger is biased by a compression spring 40 in the direction of the arrow A so as to cause the seal 39 to make a fluid-tight seal against the valve seat 20. Said sleeve 34 is further bored to form a passageway 41 which extends as far as a valve seat 42 against which the seal 38 will be forced to hear so as to create a fluid-tight seal when the solenoid is energized.

The cup 27 may of course be made of metal, in which case the O-ring should be made of P.T.F.E. or material having similar properties, or other means such as prelubrication would have to be adopted to avoid or minimize wear due to friction.

- The operation of the direction-control valve is as follows:

As illustrated, fluid (namely, air or a gas or a mixture of gases) at super-atmospheric pressure is passing along the

passageways

25 and 19 and entering the chamber 18 by virtue of the fact that the solenoid 33 has been energized thereby lifting the seal 39 off the valve seat 20 and creating a fluid-tight seal at the valve seat 42. From the chamber 18, said fluid is free to pass:

a. along the

passageways

21 and 22 into the chamber in which the exhaust port 12 is located, said one exhaust port 12 having a cup-seal (also referred to herein as a first port closure means) 43 associated therewith. Said cup-seal 43 has been forced into fluid-tight sealing contact with the exhaust port 12 and is deformed by said fluid, thereby permitting said fluid to pass through the cylinder port 15.

b. along the

passageways

23 and 24 to the underside (as seen in FIG. 2) of the reciprocatable poppet valve 28 thereby moving said poppet valve 28 in the same axial direction as that in which said plunger 37 was moved when the solenoid 33 was energized and thereby causing a fluid-tight seal to be made between one axially directed face of the ring 30 and the axially directed end face of the chamber 16, as clearly can be seen in FIGS. 2 and 3.

Said axial movement of the poppet valve 28 exhausts used fluid from the passageway 17 to atmosphere by way of the radial hole in the wall of the cup 27 and the passageway 32 aligned with said hole, that is, the used fluid which was keeping the exhaust port 13 closed by means of a cup-seal (also referred to herein as a second port closure means) 44 is exhausted with the result that said cup-seal 44 is moved to the left into the position thereof illustrated in FIG. 2 and permits the exhaust of used fluid through the cylinder port 14.

Upon de-energization of the solenoid 33, the plunger 37 is moved in the direction indicated by the arrow A to create a fluid-tight seal at the valve seat 20. Thereupon, the fluid in the passageway is free to pass into the chamber 16 by displacement of the poppet valve 28 in the same direction as that in which said plunger has already been moved. The poppet valve 28 is quite free to move in said direction because, when the plunger 37 moved under spring influence to seal against the valve seat 20 the passageway 41 was opened by the fluid-tight seal against the valve seat 42 being broken and thus the used fluid at super-atmospheric pressure which had previously moved the poppet valve 28 upwardly as seen in FIG. 2 is at once exhausted to atmosphere by way of the

passageways

24, 23, the chamber 18, the clearance between the plunger 37 and the sleeve 34 and the passageway 41. It will be appreciated that the movement of said poppet valve 28 is small and rapidly effected and that the relevant axially directed face of the ring 30 makes contact and a fluid-tight seal with the bottom of the cup 27 so as to seal the aperture through which the stem 29 of the poppet valve 28 extends. Thus, said fluid quickly acts upon the cup-seal 44 to close the exhaust port 13 and then deforms the skirt of said cup-seal 44 to pass through the cylinder port 14.

As to the cup-seal 43 upon de-energization of said solenoid, the used fluid which kept the exhaust port 12 closed is exhausted to atmosphere by way of Y the

passageways

22, 21, the clearance between the plunger 37 and the sleeve 34 and the passageway 41 with the result that said cup-seal 43 has a considerablepressure drop across it due to the pressure of fluid at super-atmospheric pressure at the cylinder port 15. This pressure drop effects opening of the exhaust port 12 by displacement of said cup-seal 43 to the right as seen in FIG. 2, and consequent exhaust of said fluid to atmosphere through said cylinder port 15 and exhaust port 12.

It will be appreciated that speed control throttling screws can be added to obturate the

exhaust ports

12, 13 to the required degree and such speed control throttling screws are indicated by the

reference numerals

50 and 51 in FIG. 4.

It has been found to be desirable to provide a seal which is fluid-tight between the radially outer surface of the right-cylindrical cup 27 and the adjacent wall of that part of the chamber 16 in which said cup is located because there is a tendency for the pressurized fluid to leak between said two surfaces into the radially extending passageway 32 and thence to atmosphere. It is considered that the most satisfactory form of seal is obtained by the provision of a pair of spaced O-rings 52, 53 (see FIGS. 4 and 5) extending around the cup 27, one of said O-rings being placed above the radially inner end of said passageway 32 as seen in FIG. 5 and the other of said O-rings being placed below said radially inner end.

The seal could, however, be obtained in other ways, for example, by coating the radially outer surface of said cup 27 with a composition such, for example, as Locktite before said cup is placed in said bore, and thereafter pushing said cup into position.

Whatl claim as my invention and desire to secure by Letters Patent of the United States is:

1. A direction-control valve which includes a valve body, means defining a first exhaust port in said valve body and other means defining a second exhaust port in said valve body, a first port closure means operative in response to a pressure differential thereacross to open and to close said first exhaust port, second portclosure means operative in response to a pressure differential thereacross to open and to close said second exhaust port, further means defining first and second cylinder ports which are in communication with the first and second exhaust ports, respectively, said first and said second cylinder ports being connectible to a doubleacting cylinder, first spaced valve seats, a reciprocatable poppet valve housed by said valve body, and reciprocatable between said valve seats, additional means defining passageways for the supply of a pressurized fluid to said first and said second cylinder ports alternately, second spaced valve seats, and another valve, said other valve being displaceable between said second spaced valve seats, displacement of said other valve in a first direction of motion towards and into sealing contact with one of said second spaced valve seats causing (when said direction-control valve is in use) said pressurized fluid to flow past the first exhaust port which has become closed by movement of said first port closure means to the double-acting cylinder by way of the first cylinder port and causing used pressurized fluid to become exhausted from said doubleacting cylinder by way of said second cylinder port and said second exhaust port which has become opened by movement of said second port closure means, and displacement of said other valve in a second direction of motion which is the opposite of the first direction of motion thereof towards and into sealing contact with the other of said second spaced valve seats causing (when said direction-control valve is in use) said pressurized fluid to flow past the second exhaust port which has become closed by movement of said second port closure means to the double-acting cylinder by way of the second cylinder port and causing used pressurized fluid to become exhausted from said double-acting cylinder by way of said first cylinder port and causing used pressurized fluid to become exhausted from said double-acting cylinder by way of said first cylinder port and said first exhaust port which has become opened by movement of said first port closure means.

2. A direction-control valve as claimed in claim 1, wherein said other valve comprises an element having opposite end faces, each of said end faces incorporating sealing devices, a sleeve having ends, one of said sleeve ends being formed with connecting means, second connecting means in said valve body and complementary to said first-mentioned connecting means whereby said sleeve is securely mountable upon said valve body, means defining abutments on each of said sleeve and said element, spring means interposed between said abutments in order to bias said element towards and into sealing contact with the one or the other of the second spaced valve seats, the other of said sleeve ends having means defining an exhaust passageway therethrough, and a solenoid encircling said sleeve and having means whereby electricity may be caused to flow through the coil, energization of said solenoid by passage of electricity through said coil causing said element to overcome the bias of said spring means, whereby the operation of said doubleacting cylinder is controlled by the direction-control valve in response to energization and de-energization of said solenoid.

3. A valve assembly for controlling the operation of a double-acting cylinder, comprising:

a. four-way, five-port valve, comprising:

1. a first cylinder port,

2. a second cylinder port,

3. a first exhaust port,

4. a second exhaust port, and 5. an inlet port;

b. means for communicating said cylinder ports with said exhaust ports;

c. first port closure means responsive to fluid pressure for selectively connecting said first exhaust port to atmospheric pressure and said second exhaust port to said fluid pressure inlet port;

d. second port closure means responsive to fluid pressure for selectively connecting said second exhaust port to atmospheric pressure and said first exhaust port to said fluid pressure inlet port; and

e. means for alternately applying fluid pressure from said inlet port to said first and second port closure means, to alternatively actuate said port closure means.

4. A valve assembly according to claim 3, wherein said means for alternately applying fluid pressure comprises first and second chambers, passage means connecting said chambers to each other and to said exhaust ports, a cup member in said first chamber, a reciprocatable poppet valve for actuating said cup member, and a solenoid poppet valve in said second chamber having a movable plunger for controlling the inflow and direction of flow of pressure fluid.

5. A valve assembly according to claim 4, wherein said reciprocatable poppet valve and said solenoid poppet valve are mounted coaxially with respect to each other.

6. A valve assembly according to claim 5, wherein said solenoid poppet valve plunger is spring-biased in a direction which permits the movement of said reciprocatable poppet valve by said fluid.

7. A valve assembly as claimed in claim 4, wherein said reciprocatable poppet valve is carried by a valve stem at one end thereof, said stem having in the vicinity of the other end thereof a seat containing an O-ring which seals against the inner surface of said cup member, said cup member being a right cylindrical cup made of a material having a low coefficient of friction, said stem extending through an aperture in the bottom wall of said cup and said one end of said stem being located outside the confines of said cup and said other end thereof being located within the confines of said cup, said first chamber comprising an orifice therein,

the movements of said reciprocatable poppet valve under the influence of said pressure fluid at super-atmospheric pressure causing said poppet valve to seal said aperture and said orifice of said first chamber alternately to effect alternate opening and closure of one of said exhaust ports by its associated port closure means.

prevent leakage to atmosphere of said pressurized- 11. A valve assembly according to claim 3, wherein said port closure means comprise cup valves.

12. A valve assembly according to claim 3, further including additional exhaust port means for creating i 1 t t l

Claims

1. A direction-control valve which includes a valve body, means defining a first exhaust port in said valve body and other means defining a second exhaust port in said valve body, a first port closure means operative in response to a pressure differential thereacross to open and to close said first exhaust port, second port closure means operative in response to a pressure differential thereacross to open and to close said second exhaust port, further means defining first and second cylinder ports which are in communication with the first and second exhaust ports, respectively, said first and said second cylinder ports being connectible to a double-acting cylinder, first spaced valve seats, a reciprocatable poppet valve housed by said valve body, and reciprocatable between said valve seats, additional means defining passageways for the supply of a pressurized fluid to said first and said second cylinder ports alternately, second spaced valve seats, and another valve, said other valve being displaceable between said second spaced valve seats, displacement of said other valve in a first direction of motion towards and into sealing contact with one of said second spaced valve seats causing (when said direction-control valve is in use) said pressurized fluid to flow past the first exhaust port which has become closed by movement of said first port closure means to the double-acting cylinder by way of the first cylinder port and causing used pressurized fluid to become exhausted from said double-acting cylinder by way of said second cylinder port and said second exhaust port which has become opened by movement of said second port closure means, and displacement of said other valve in a second direction of motion which is the opposite of the first direction Of motion thereof towards and into sealing contact with the other of said second spaced valve seats causing (when said direction-control valve is in use) said pressurized fluid to flow past the second exhaust port which has become closed by movement of said second port closure means to the double-acting cylinder by way of the second cylinder port and causing used pressurized fluid to become exhausted from said double-acting cylinder by way of said first cylinder port and causing used pressurized fluid to become exhausted from said double-acting cylinder by way of said first cylinder port and said first exhaust port which has become opened by movement of said first port closure means.

2. A direction-control valve as claimed in claim 1, wherein said other valve comprises an element having opposite end faces, each of said end faces incorporating sealing devices, a sleeve having ends, one of said sleeve ends being formed with connecting means, second connecting means in said valve body and complementary to said first-mentioned connecting means whereby said sleeve is securely mountable upon said valve body, means defining abutments on each of said sleeve and said element, spring means interposed between said abutments in order to bias said element towards and into sealing contact with the one or the other of the second spaced valve seats, the other of said sleeve ends having means defining an exhaust passageway therethrough, and a solenoid encircling said sleeve and having means whereby electricity may be caused to flow through the coil, energization of said solenoid by passage of electricity through said coil causing said element to overcome the bias of said spring means, whereby the operation of said double-acting cylinder is controlled by the direction-control valve in response to energization and de-energization of said solenoid.

2. a second cylinder port,

3. a first exhaust port,

3. A valve assembly for controlling the operation of a double-acting cylinder, comprising: a. four-way, five-port valve, comprising:

4. a second exhaust port, and

5. an inlet port; b. means for communicating said cylinder ports with said exhaust ports; c. first port closure means responsive to fluid pressure for selectively connecting said first exhaust port to atmospheric pressure and said second exhaust port to said fluid pressure inlet port; d. second port closure means responsive to fluid pressure for selectively connecting said second exhaust port to atmospheric pressure and said first exhaust port to said fluid pressure inlet port; and e. means for alternately applying fluid pressure from said inlet port to said first and second port closure means, to alternatively actuate said port closure means.

7. A valve assembly as claimed in claim 4, wherein said reciprocatable poppet valve is carried by a valve stem at one end thereof, said stem having in the vicinity of the other end thereof a seat containing an O-ring which seals against the inner surface of said cup member, said cup member being a right cylindrical cup made of a material having a low coefficient of friction, said stem extending through an aperture in the bottom wall of said cup and said one end of said stem being located outside the confines of said cup and said other end thereof being located within the confines of said cup, said first chamber comprising an orifice therein, the movements of said reciprocatable poppet valve under the influence of said pressure fluid at super-atmospheric pressure causing said poppet valve to seal said aperture and said orifice of said first chamber alternately to effect alternate opening and closure of one of said exhaust ports by its associated port closure means.

8. A valve as claimed in claim 7, wherein a pneumatic seal is provided between the adjacent surfaces of the cup and said first chamber, whereby any tendency of the pressurized fluid to leak between said adjacent surfaces to atmosphere is prevented.

9. A valve as claimed in claim 8, wherein said pneumatic seal is constituted by a sealing material.

10. A valve as claimed in claim 8, wherein said pneumatic seal is constituted by two spaced O-rings carried by the cup, the spacing of said O-rings being such as to prevent leakage to atmosphere of said pressurized fluid.

11. A valve assembly according to claim 3, wherein said port closure means comprise cup valves.

12. A valve assembly according to claim 3, further including additional exhaust port means for creating fluid pressure differentials across said port closure means.