US3156257A

US3156257A - Flow control valve

Info

Publication number: US3156257A
Application number: US153383A
Authority: US
Inventors: Don S Strader
Original assignee: Frank G Hough Co
Current assignee: Frank G Hough Co
Priority date: 1961-11-20
Filing date: 1961-11-20
Publication date: 1964-11-10
Anticipated expiration: 1981-11-10

Description

Nov. 10, 1964 D. s. STRADER 3,155,257

FLOW CONTROL VALVE Filed Nov. 20. 1961 gjr jgf INVENTOR.

United States Patent 3,156,257 FLOW CONTROL VALVE Don S. Strader, Mount Prospect, 11]., assignor to The Frank G. Hough Co., a corporation of Illinois Filed Nov. 20, 1961, Ser. No. 153,383 8 Claims. or. 137-494 fluid pressure is delivered to the motor.

Afurther object of the invention is to provide a flow control valve which may be used in combination with a second flow control valve to block both ends of a hydraulic fluid motor when no hydraulic fluid pressure is delivered to either flow control valve to thereby lock the hydraulic motor in any operated position thereof.

A further object of the invention is to provide a flow control valve arrangement of two valves in combination with a pair of hydraulic fluid motors, in a system wherein the motors are connected to operate in opposite directions, to lock the motors in any operated position by blocking fluid at one end of each of the hydraulic motors, when no hydraulic fluid under pressure is delivered to either of the hydraulic fluid motors.

It is a further object of the invention to provide a pair of flow control valves which are interconnected and which may be applied to any hydraulic motor means for preventing fluid flow to or from said motor means when no hydraulic fluid pressure is applied to either of said flow control valves from a source of hydraulic fluid under pressure.

Other objects and features of the invention will be apparent upon a perusal of the following specification and drawing in which:

FIGURE 1 is a cross sectional view of a flow control valve constructed according to the invention;

FIGURE 2 is a plan view of a hydraulic motor and flow control valve arrangement of the invention; and

FIGURE 3 is a plan view of another application of the flow control valve of the subject invention to a hydraulic motor arrangement.

The present embodiment is the preferred embodi ment, but it is to be understood that changes can be made in the present embodiment by one skilled in the art without departing from the spirit and scope of the present invention.

Generally, the flow control valve of the subject invention comprises a valve housing with a valve spool slidably carried therein. The spool is spring biased to close oil the motor port when no hydraulic fluid is delivered to the pressure port. It is intended that the flow control valve of the subject invention be used in pairs, and the two flow control valves are interconnected by a pilot conduit which is connected into each valve bore at one end thereof. An orifice is provided through the valve spool to the pilot conduit connection. The orifice is always open to the pressure port. The end of the valve spool as sociated with the pilot conduit carries a spring biased check valve which will open under the application of operate that valve spool to interconnect the motor port 7 and pressure or drain port of that valve. The flow control valve at which the fluid pressure is directly applied will operate under the effect of the fluid pressure acting on the valve spool and against the bias of the spool biasing spring. The motor port of each flow control valve is then open to its pressure or drain port and hydraulic fluid may then flow in series through one valve, the motor arrangement, and the other valve. When hydraulic fluid pressure is removed from the flow control valves, the spool biasing springs in the flow control valves will return the valve spools to block the motor ports and any fluid under pressure in the pilot conduit may drain through one of the orifices to the drain line. FIGURES 2 and 3 show two ditferent applications of the flow control valves of the invention to hydraulic motor arrangements. Other combinations of motors may be used with the subject invention. It should further be noted that in the present invention the fluid pressures for operating the motors are substantially independent of the pilot pressure.

'In detail, the valve body It) is provided with a cylindrical valve bore 11 formed therethrough. One end of the valve bore 11 is closed by a cap 12 and the other end thereof is closed by a cap 13. A sealing ring 14 positioned in an annular groove formed in the valve body 10 cooperates with the cap 13 to prevent the leakage of hydraulic fluid from the valve bore 11. The valve body It) is further provided with a drain port 16 and a pressure port 17 axially spaced from each other and con nected into the valve bore 11.

The valve spool 20 comprises three interconnected

cylindrical sections

21, 22 and 23. The spool sections or

lands

21 and 23 have an outer diameter substantially equal to the diameter of the valve bore 11. The spool section or annular groove 22 is disposed between the

spool sections

21 and 23 and has an outer diameter substantially less than the diameter of the valve bore 11. A cylindrical hole 21a is formed in the end of spool section 21. A compressed coiled spring 24 is carried in the valve bore 11 with one end thereof engaging the cap 12 and with the other end thereof engaging the inner wall of the cylindrical hole 21a to bias the spool section 23 against the cap 13. A passageway 25 formed through cap 12 into the valve bore 11 is connected by any means (not shown) to a drain or reservoir line. An annular groove formed in the valve bore 11 at a position between the drain port 16 and the cap 12 carries a sealing ring 27 which minimizes the leakage of any hydraulic fluid from

ports

15 and 17 into the valve bore 11 adjacent cap 12.

The spool section or annular groove 22 is of such a length that the annular groove 22 is in free fluid communication with port 17 in all operated positions of the valve spool 20. The drain or motor port 16 is positioned so that the outer cylindrical surface of the spool section 21 blocks port 16 from any fluid communication with pressure port 17 when the spool section 23 engages the cap 13; and when the valve spool 20 is moved away from cap 13 against the bias of spring 24, the

ports

16 and 17 are interconnected through the annular groove 22.

The spool section 22 is provided with a diametral passageway 30, and an axial passageway 31 connected into the diametral passageway 30 by an orifice 32. The passageway 31 also is connected into a cylindrical cavity or recess 23a formed in the end of the spool section 23.

The spool section 23 is provided with a plurality of holes 34 extending between the recess 23a and the radially extending wall portion 23b of the annular groove 22. From the foregoing it may be seen that the holes 34 and the orifice 32 are always exposed to any fluid pressure at pressure port 17.

A check valve is provided in the recess 23a and comprises a washer-shaped valve head 36 positioned against o the ends of the holes 34. The washer-shaped valve head 36 has an outer diameter substantially equal to the diameter of the recess 23a, and an inner diameter substantially equal to the diameter of passageway 31. A spring Washer or dish-shaped spring 37 is provided for biasing the valve head 36 in a fluid sealing or blocking relationship against the ends of the holes 34. The spring washer 37 is disposed against the opposite side of the washer 36 from that which blocks the ends of the holes 34 and is retained within the recess 23a by a snap ring 38 which is carried in a suitable groove formed in the recess 23a. Thus it may be seen that the holes 34 normally are not in free fluid communication with the recess 23a of the spool section 23 due to the seating of the valve head or washer 36 against the ends of the holes 34 by the spring washer 37. The hole through the spring Washer 37 provides free fluid communication between the recess 23a and the passageway 31.

The cap 13 is provided with a pilot port therethrough to which is connected the pilot conduit 40. In a motor arrangement such as shown in FIGURE 2, a single pilot conduit 49 is connected between the pilot ports of two identical valves constructed according to the foregoing description. The hydraulic motor of FIGURE 2 and also the motors of FIGURE 3 are shown by way of example and may be constructed in any well known manner. Each hydraulic motor comprises a cylinder assembly 41 which has a port 42 at one end thereof and a port 43 at the other end thereof. The head end of the cylinder assembly 41 carries a flange 44 for connecting the head end of the motor in some tool arrangement. A piston assembly 45 is carried in the cylinder assembly 41 for reciprocating movement therein between the

ports

42 and 43. The end of the piston rod carries a flange 46 for connecting the rod end of the hydraulic motor in some tool arrangement. In the arrangement of FIG- URE 3, the flanges 46 are pivotally connected one at each end of a lever 47 which midway of its ends is pivotally mounted, as at 43, in some construction wherein one of the motors is extended as the other is retracted.

In FIGURE 2, the pressure port 17 of one valve is connected to a hydraulic fluid conduit t) and the pressure port 17 of the other valve is connected to a hydraulic fluid conduit 51. The drain port 16 of the first valve is connected by a hydraulic fluid conduit 52 into the port 42 at the head end of the hydraulic motor. The drain port 16 of the other valve is connected by a hydraulic fluid conduit 53 into the port 43 at the rod end of the hydraulic motor. It is intended that the

hydraulic fluid conduits

50 and 51 be connected in any well known arrangement to a control valve and hydraulic fluid pressure and drain means so that selectively either one of the

conduits

50 or 51 may be connected to a source of hydraulic fluid pressure while the other conduit is connected to a drain or reservoir line. It is further importantly intended that in any operated position of the motor, the hydraulic fluid under pressure may be removed from the

conduits

50 and 51. Firstly it may be seen that if no hydraulic fluid under pressure is delivered to either of the

conduits

50 or 51, the valves will each be operated to the position shown in FIGURE 1, wherein the compressed coiled spring 24 will bias the spool so that the land 21 will block the drain port 16. Thus the hydraulic motor will be locked in some operated position and any load upon the hydraulic motor will be ineflectual to cause any unlocking of the valves.

If hydraulic fluid conduit 50 is connected to a source of hydraulic fluid under pressure, while conduit 51 is connected to a drain or reservoir line, it may be seen that the hydraulic fluid under pressure applied to port 17 of the one valve will enter the annular groove 22. As the pressure of the hydraulic fluid in annular groove 22 rises, the hydraulic fluid under pressure will act against the valve head 36 through holes 34. When the'hydraulic fluid pressure is high enough to unseat valve head 36 against the bias of the washer spring 37, hydraulic fluid will then flow from annular groove 22 through holes 34, recess 23a and pilot conduit 40 into the recess 23a, moving spool 20 left against spring 24. Additional volume of hydraulic fluid flow from the one valve through the pilot conduit 40 into the recess 23a of the other valve will cause the valve spool 20 of the latter valve to be moved against the bias of its coiled spring 24 toward the cap 12 to interconnect

ports

16 and 17 thereof in free fluid communication. The hydraulic fluid under pressure in the annular groove 22 of the first valve, that having conduit 50 connected thereto, will cause that valve to be operated against the bias of coiled spring 24 to interconnect the

ports

16 and 17 thereof in free fluid communication. The hydraulic fluid under pressure in conduit 50 may then freely flow from port 17 through valve bore 11, port 16, conduit 52, and motor port 42 into the head end of the motor. As the piston assembly 4-5 is moved outwardly of the motor, hydraulic fluid in the rod end of the motor cylinder assembly 41 will flow through motor port 43, conduit 53, port 16 of the second valve, and annular groove 22 and port 17 thereof and through conduit 51 to the drain or reservoir.

When the hydraulic fluid pressure in conduit 50 is removed, the motor will no longer be operated and the coiled spring 24 in the second valve, that connected to conduit 51, will restore the valve spool 29 therein to block port 16 thereof. As the spool 20 in the first valve, that connected to conduit 50, is moved toward the restored position by the compressed coil spring 24, the fluid in the valve bore 11 thereof at the end connected to pilot conduit 49, will flow through pilot conduit 40 into the recess 23a of the second valve. The fluid in the recess 23a of the second valve will flow through the passageway 31, orifice 32 and passageway 3t thereof thereby permitting the valve spool 20 of the first valve to restore blocking port 16 thereof. Thus it may be seen that the orifices 32 permit the valves to restore when hydraulic fluid pressure is removed from the valves.

If conduit 5% is connected to a drain line and conduit 51 is connected to a source of hydraulic fluid under pressure, the valve connected to conduit 51 will be opened by that hydraulic fluid pressure acting against spool end 23 in the recess 23a thereof, and the other valve will be operated to its open position by hydraulic fluid pressure applied through the pilot conduit 41').

The arrangement of FIGURE 3 shows the use of one flow control valve on each of two hydraulic motors which are mechanically interconnected to operate in opposite directions. In this instance the port 16 of one valve is connected by conduit 52 to the port 42 of one hydraulic motor, and the port 16 of the second valve is connected by conduit 52 to port 42 of the other hydraulic motor. A conduit 53 at the rod ends of the hydraulic motors may be interconnected or may be connected to another source of hydraulic fluid under pressure and a drain line. The valves of the arrangement of FIGURE 3 will operate substantially as the valves of the arrangement of FIGURE 2. If hydraulic fluid under pressure is delivered through conduit 50 to the flow control valve connected thereto, and the conduit 51 of the other valve is connected to a drain or reservoir line, the first valve will be operated by hydraulic fluid pressure at recess 23a against the spool end section 23 thereof and the second valve will be operated to the open position by the hydraulic fluid flow through pilot conduit 40. Again, upon the removal of hydraulic fluid pressure, the valve' connected to the drain line will restore under the influence of the coiled spring 24 thereof, and the other valve, that which was connected to the fluid under pressure, will restore under the influence of the compressed coil spring 24 thereof as the fluid in the recess 23a and valve bore 11 thereof drains through the pilot conduit 40 and the orifice 32 of the other valve.

Having described the invention, what is considered new and desired to be protected by Letters Patent is:

l. A fluid flow control device comprising, a valve body having a valve bore formed therein, a valve spool slidably carried in said valve bore, a pilot conduit connected into one end of said valve bore, a compressed coiled sprin carried in the other end of said valve bore and engaging one end of said valve spool to bias the other end of said valve spool against said one end of said valve bore, a pressure port and a drain port connected into said valve bore in a spaced apart relationship to each other, said valve spool formed to block said drain port when said valve spool is positioned against said one end of said valve bore, the intermediate portion of said valve spool being formed of a reduced diameter and positioned in free fluid communication with said pressure port when said other end of said valve spool is positioned against said one end of said valve bore and connecting said pres sure and drain ports in free fluid communication when said valve spool is moved away from said one end of said valve bore, an orifice connected between the surface of said reduced section of said valve spool and said other end of said valve spool, and check valve means carried in said other end of said valve spool and operable to permit substantial fluid flow from said intermediate portion of said valve spool to said other end of said valve spool.

2. A fluid flow control device comprising, a valve body having a valve bore tor-med therein, a pilot conduit connected into one end of said valve bore, a valve spool slid ably carried in said valve bore, spring means biasing one end of said valve spool against said one end of said valve bore, a pressure port and a drain port-connected into said valve bore, said valve spool formed to have an annular groove formed therein intermediate the ends thereof, said annular groove positioned in free fluid communication with said pressure port in all operated positions of said valve spool, said valve spool further being formed to block said drain port when said one end of said valve spool is positioned against said one end of said valve bore and interconnecting said pressure port and said drain port through said annular groove when said one end of said A valve spool is moved away from said one end of said valve bore, the radially extending side wall of said annular groove toward said one end of said valve spool having a plurality of openings extending into a recess formed in said one end of said valve spool, and check valve means carried in said recess and operable responsive to a certain hydraulic fluid pressure in said annular groove to permit substantial fluid flow from said annular groove to said pilot conduit.

3. A fluid flow control device as defined in claim 2, wherein an orifice is provided in said valve spool and connected between said recess and said annular groove.

4. A fluid flow control device as defined in claim 2, wherein said check valve comprises a valve head having one side thereof positioned to engage the ends of said plurality of openings in said recess in a fluid blocking relationship, and spring means biasing said valve head against said ends of said openings in said recess.

5. A fluid flow control device as defined in claim 2, a fluid passageway extending from the surface of said annular groove and axially through said valve spool into said recess, an orifice formed in said passageway intermediate the ends thereof, said check valve comprising a washer having one side thereof positioned to engage the ends of said plurality of openings in said recess in a fluid-blocking relationship and having the hole through said washer in axial alignment with the end of said passageway terminating in said recess, and a washer spring retained within said recess and biasing said washer against said ends of said openings in said recess.

6. A fluid flow control device comprising,

a valve body having a valve bore formed therein,

a pilot conduit connected into one end of said valve bore, a valve spool having two end portions of a diameter substantially equal to the diameter of said valve bore, said valve spool further being formed to have an annular groove between said two end portions, said valve spool slidably carried in said valve bore, spring means carried in said valve bore and engaging the end of one end portion of said valve spool to bias the other end portion of said valve spool against said one end of said valve bore, a pressure port and a drain port connected into said valve bore, said annular groove of said valve spool having a length so that said pressure port is in free fluid communication with said annular groove in all operated positions of said valve spool, said drain port being positioned in said valve body so that the outer surface of said one end portion of said valve spool blocks said drain port when said other end portion of said valve spool is positioned against said one end of said valve bore and so that said pressure and drain ports are interconnected through said annular groove when said other end portion of said valve spool is moved away from said one end of said valve bore, a recess formed in the end of said other end portion of said valve spool, the side wall which extends radially from said annular groove to the outer periphery of said other end portion of said valve spool having a plurality of openings extending therethrough into said recess, and check valve means carried in said recess and operating to block any hydraulic fluid flow from said recess into said annular groove while permitting substantial fluid flow from said annular groove into said recess responsive to a certain hydraulic fluid pressure in said annular groove, a passageway formed in said valve spool and extending between said annular groove and said recess, and an orifice formed in said passageway intermediate the ends thereof.

7. A fluid flow control device as defined in claim 6, wherein said check valve means comprises a washer having one end thereof positioned to engage the ends of said plurality of openings in said recess in a fluid-blocking relationship and having the hole through said washer in axial alignment with the termination of said passageway in said recess, and spring means biasing said Washer against said ends of said openings in said recess.

8. A fluid flow control device comprising, a valve body having a valve bore formed therein, a pilot conduit connected into one end of said valve bore, a valve spool slidably carried in said valve bore and having one end biased against said one end of said valve bore, a pressure port and a drain port connected into said valve bore, said valve spool having an annular groove and an annular land position so said annular groove is in free fluid communication with said pressure port in all operated positions of said valve spool and so that said land blocks said drain port when said valve spool engages said one end of said valve bore and said drain port and said pressure port are interconnected by said annular groove when said valve spool is moved away from said one end of said valve bore, a passageway in said valve spool extending between said annular groove and said one end of said valve bore, an orifice formed in said passageway intermediate the ends thereof, and check valve means carried in said one end of said valve spool and operable responsive to hydraulic fluid pressure in said annular groove to permit substantial fluid flow from said annular groove to said pilot conduit.

References Cited in the file of this patent UNITED STATES PATENTS 2,411,837 Stephens Nov. 26, 1946 2,756,724 Stewart et a1 July 31, 1956 2,870,781 Tennis Ian. 27, 1959