US2619118A

US2619118A - Control valve for hydraulic apparatus

Info

Publication number: US2619118A
Application number: US47687A
Authority: US
Inventors: Cecil E Adams
Original assignee: Denison Engineering Co
Current assignee: Denison Engineering Co
Priority date: 1948-09-03
Filing date: 1948-09-03
Publication date: 1952-11-25
Anticipated expiration: 1969-11-25

Description

Nov. 25, 1952 C. E. ADAMS CONTROL VALVE FOR HYDRAULIC APPARATUS Filed Sept. 5, 1948 3 Sheets-Sheet l INVENToR. OE C! L E. ADAMS Nov. 25, 1952 Q E ADAMS 2,619,118

CONTROL VALVE FOR HYDRAULIC APPARATUS Filed Sept. 3, 1948 3 Sheets-Sheet 2 28 mvx 26 O 29 5l T l 5 53 3o l W r 7 `3| /50 3 46` l /23 u I 5552 'i '25 -m f E 59 Y llll G' 1 INVENTOR. GEC/L 'E ADAMS Nov. 25, 1952 c. E. ADAMS 2,619,118

CONTROL VALVE FOR HYDRAULIC APPARATUS I N VEN TOR.

@Ec/L E. A0A/ws BY Patented Nov. 25, 195.2

UNITED STATES PATENT OFFICE CONTROL VALVE FOR HYDRAULIC APPARATUS Cecil E. Adams, Columbus, Ohio, assignor to The Denison Engineering Company,

Columbus,

8 Claims.

This invention relates generally to the science of hydraulic-s and is more particularly directed to mechanism .for controlling the operation of hydraulically actuated apparatus.

An object of this invention is to provide a valve mechanism for controlling the operation of hydraulically driven motors especially those of the piston and cylinder type.

This invention relates to the type of control valve -mechanism forming the subject matter of my copending application Serial No. 545,700, filed July 19, 1944, now Patent No. 2,464,283 dated March l5, 1949, of which this application is a continuation-impart.

Another object of the invention is to provide a valve mechanism for controlling the operation of the piston in a hydraulic cylinder, the valve having mechanism to provide for rapid m-ovement of the piston during a porti-n of its travel in the cylinder and additional mechanism to control the rate of movement of the piston during the remainder of its travel in the cylinder, such control being secured through the utiliza-tion of ilu-id pressure.

A further object of the inventi-o-n is to provide a control valve mechanism having a movable valve element which is formed to include passage establishing means operative in one position of the valve element to connect with both ends of a hydraulic cylinder with a source of uid pressure and in another position to connect one end of the cylinder with the source of fluid pressure and the opposite end with exhaust, the valve being provided also with means responsive to fluid pressure to establish communication between the end of the power cylinder connected with the source of pressure, and the exhaust simultaneously with its connection with the pressure source, a portion of the pressure thus being directed to exhaust to decrease the rate of movement of the piston in the power cylinder.

A still further object of the invention is to provide a control valve mechanism having a casing with a bore and a plurality of longitudinally spaced ports, one of these ports being adapted for connection with a source of fluid pressure, a pair of the ports being formed for connection with the ends of the power cylinder, these ports being spaced at either side of the pressure receiving port, and a pair of exhaust ports being disposed at the outer sides of the cylinder ports, the bore in the casing receiving a valve element having passage-forming means whereby communication may be established between the pressure inlet port and exhaust so that the pump 2 may be unloaded when the motor controlled by the valve mechanism is not in operation; between the pressure inlet port and both cylinder ports when it is desired to cause high speed operation of the motor controlled by the valve mechanism; between the pressure inlet port, both cylinder ports and an exhaust port to cause the valve mechanism to serve as a low pressure relief valve when the mot-or is stalled while operating under reduced power; between the pressure inlet port and one cylinder port while the other cylinder port is connected with exhaust when the motor is performing a working operal tion at a normal speed or operating in a reverse direction and between a certain cylinder port and an exhaust port while the cylinder port is in communication with the pres-sure inlet, port, the other cylinder port being connected with an exhaust port through a valve controlled passage, the degree of uid ow through the passage determining the degree of communication between the cylinder port connected with the pressure source, and the exhaust port.

Another object of the invention is to provide a valve mechanism of the type set forth in the preceding paragraph with means to regulate the degree of communicati-on between one of the cylinder ports and the exhaust port whereby a u-id pressure may be created which is utilized to establish communication between the other cylinder port and exhaust While such cylinder port is communicating with the pressure port.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accomlpanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Fig. 1 is a vertical longitudinal sectional View taken through a control valve mechanism formed in accordance with the present invention, the parts of the control valve mechanism being shown in a position to cause the ram of a power cylinder` to remain in a retracted stationary position.

Fig. 2 is a similar view taken through the control valve mechanism showing the parts of the mechanism in position to cause a rapid traverse of the ram of the power cylinder, this figure also showing diagrammatically, a hydraulic system in which the valve mechanism may be incorporated.

Fig. 3 is also a similar View taken through the valve mechanism showing the parts of the mechanism in a position occupied when the ram of the power cylinder has engaged an article of 'work immediately prior to the manual shifting of the valve elements to cause the ram of the power cylinder to deliver the full pressing force.

Fig. 4 is a vertical, longitudinal sectional view taken through the valve mechanism showing the parts thereof in-position tocause the full pressing force to `be exerted, parts of the valve mechanism also being shown in the rposition which they will occupy when theram is moved at .a controlled rate, and,

Fig. 5 isa sectional .viewshowingzthe position occupied by the parts during the return.move

ment -of the power cylinder ram.

Referring more particularly to the drawings, the numeral designates the control mechanism in its entirety. This mechanism includes a casing 3|, which may be cast or otherwise formed of suitable material, this casing has a vertical bore 22 formed therein; the bore being surrounded by a plurality of longitudinally spaced annular recesses 23 to 21, inclusive, which constitute fluid ports, these recesses being in open communication with the bore. Recess 23 constitutes the inlet port and is adapted when the control valve mechanism is. arranged in a hydraulic circuit to be connected with a suitable source of fluid pressure, this suitable source frequently constituting a motor driven pump 28 having a connection through line 29 with a reservoir 30.

Recesses

24 and 25 are arranged in either side of recess 23, these

recesses

24 and 25 constituting cylinder ports. Recess 24 is disposed above recess 23 and when the control valve mechanism is connected in a circuit with a power unit, such as a power cylinder 3|, it is connected with the upper or top cylinder port. It should be obvious that the control mechanism is suitable for use. with power cylinders arranged in any position, that is, upright, slanting, or, horizontal, however, throughout this description the cylinder will be referred to as if it. occupied an upright position. Recess 25 isV disposed below the recess 23 and is connected with the bottom or lower cylinder port, that is, the port below the piston 3 2 usually arrangedin the power cylinder. One of the primary functionsv of the control valve forming the subject matter of this invention is to control the operation of a ram 33 of a hydraulic press. In such devices, the ram is directly connected with the piston in the power cylinder and projects beyond the end of the power cylinder to perform useful work.

vThe outlet or

exhaust ports

25 and 21 are arranged at the opposite sides of the

cylinder ports

24 and 25 from the inl'et or pressure port 23.

Ports

26 and 21 may be connected with one another in the casing 2| and then connected with the reservoir 30 of the hydraulic system, or, separate lines may lead from ports 25Y and 21 directly to such reservoir. In either arrangement,

ports

26 and 21 contain fluid at substantially atmospheric pressure.

The bore 22 of casing 2| receives for sliding movement, a valve element 34', which is of cylindrical form and is provided with an internal recess or chamber 35. This valve element has an external shoulder 36 at its upper end to engage the upper surface ofthe casing 2| and limit the downward movement of the valve element in the casing. This element is connected at its lower end to the upper end of a shipper rod 31 forming a part of the control mechanism for the hydraulic press or other apparatus to which thev control valve mechanism is applied. Valve element 34 has its upperV endI formed with internal screw CTL threads 38 lfo'r"the 'adjustable reception of a plug 39, which closes the open upper end of the chanrber 35. Thispl'ug'lclosely nts the upper end "of the chamber 335 vand is provided with a sealing gasket -4-to-prevent the escape of iiuid from the chamber. Th'eiplug is further provided with a knurled head 94| :at its upper end to effect tlre longitudinal movement of the plug in the valve element, the positions of the plug being maintained by a lock nut `42, which is threaded onto the,plugandifrictionally engagesthe upper surface of .the .valvezelement .Plug 39 is also provided with a recessI 43 extending '.thereinto from the lower end, this recess receiving the upper end portion of a coil spring 44; the purpose of this coil spring will be set forth hereinafter.

The side wall of the valve element at the chambered portion is formed with a plurality of longitudinally spaced rows of ports 45 to 49 inclusive, which ports extend through the Wall and establish communication between the chamber and the exterior of the Valve element. When the valve element isY adjusted longitudinally in the bore 22, ports 45 to 48 inclusive, will be selectively aligned with certain of the recesses 23 to 26, inclusive. The various figures of the drawings show the valve element in different positions of adjustment wherein certain ports in the valve element are in registration with certain recesses. The purpose of this registration and the various positions of adjustment of the valve element will also be set forth.

Chamber 35 in the valve element is formed for the slidable reception of a spool-like, now-directing member 50, which member is provided at the upper and lower ends with land portions 5I and 52, which contact the wall of the chamber 35. Between these land portions, the body of the spool is reduced by an annular groove 53 which groove serves. to connect the inner ends of certain ports in the valve Wall. The external surface of the valve element 34 has an annular groove 54 formed therein substantially in registration with the lower end of the chamber 3D and below the ports 45; ata point in registration with the annular groove 54, the wall of the valve element 34 is formed with a reduced port 55 which communicates with the chamber 35 below orl at the lower end of the spool 50.

Below the inner end of the. chamber 35, the valve element 34 has longitudinally spaced passagesI 5 6. and 51 extending thereinto, the inner ends of these passages being connected by a longitudinal bore 58 formed in the valve element. The degree of communication between

passages

56 and 51 isl regulated by a tapered valve 59, which is secured to the plug 39 and extends through the chamber 35, the spool 50 and into the bore 58. Through the adjustment of the knob 4|, the1 tapered portion of the valve 58 may be moved intov or out of the bore 58 to vary the degree of communication between

ports

56 and 51..

Spool 5| is normally maintained in the lower position shown in Figs. 1, 2, and 5, by the coil spring 44, the lower end of which engages a washer surrounding the shank of valve 59 at the upper end of the spool 50. This spool is moved in opposition to the force ofthe spring, by fluid pressure introduced at the lower end of the chamber 35 through the port 55.

The operationof the valve mechanism is as follows:

Assuming the valve mechanism is arranged in a circuit-including a source of iiuid pressure and a power cylinder provided with a ram and that the latter is in a retracted inactive condition. At this time, the valve elements will occupy the positions shown in Fig. 1 wherein the valve element 34 is so located relative to the casing 2l, that ports 46 in the valve elem-ent are disposed in registration with the pressure port 23. The spool 50 will occupy its lowermost position in the chamber 35 and fluid iiowing from the pressure port 23 through the ports 4S will be directed outwardly through the ports 41 to the recess 24. inasmuch as, there is not outlet for fluid from the recess 25, which is connected with the bottom cylinder port, the piston in the power cylinder can not be extended and iiuid admitted to recess 24 will new through the ports 48 in the valve element 34 to the interior thereof above spool 55. This fluid will then flow outwardly through the ports 49 to the exhaust recess 2t which is, as previously mentioned, connected with the rerservoir of the hydraulic system. The source of fluid pressure will be unloaded at this time, which, when such source is a power operated pump, is a desirable condition.

When it is desired to cause the ram of the power cylinder to start a working stroke, the valve element 34 is moved to the position shown in Fig. 2, valve element being moved through Vany suitable medium such as a hand lever of the type shown in the above mentioned copending application. When the valve element 34 occupies the position shown in Fig. 2, ports 45 therein will be disposed in registration with the pressure port 23 so that uid admitted therethrough will be directed by the spool 55 outwardly through

ports

45 and 41 into the top cylinder recess 24 from which such fluid may flow to the upper end of the power cylinder. It will be noted from Fig. 2, that when valve element 34 occupies the position shown therein the external recess 54 establishes communication between the bottom cylinder recess 25 and the pressure port 23. Due to such communication, fluid expelled from the lower end of the power cylinder will flow from the recess 25 through the recess, or, groove 54 into the pressure port 23 from which it will ow with iluid under pressure admitted from such port `to the upper end of the power cylinder: it will Vof the ram, the reduced effective area being exposed to the entire volume of uid from the pressure source. By thus reducing the eiective area of the piston and exposing it to the entire volume of the pressure source, the rate of movement of the ram will be increased. It will, of course, be observed that through such reduction the force developed by the piston will also be reduced. This reduction in force is not objectionable since the increased rate of movement is generally employed only while the ram is moving from its retracted position toward the article of work disposed in registration therewith; since little or no resistance is encountered by the ram during its approach to the work, the

`fluid exhausted from the lower end of the power ,the pressure on the underside of the piston of -the power cylinder to increase also. This pressure will be communicated through the reduced port 55 to the chamber 35 at the under side of the spool 55 causing this spool to move upwardly in opposition to the spring 44. When the iluid pressure increases sufliciently the now-directing spool 5S will be moved to the position shown in Fig. 3, wherein the groove 53 will establish communication between

ports

45, 46, 41, and 48, the latter ports then being in registration with the exhaust port 2G. At this time, all of the fluid from the pressure port 23 will be by-passed directly to the reservoir, causing the valve mechanism to function in the manner of a, low pressure relief valve.l At this time, also, the operator cf the press, by observing a gauge connected in the system, will be apprised of the fact that the pressure in the system is insufcient to cause the ram to exert the full tonnage for which the main relief valve has been previously set. The operator will then know that to cause the press to exert the desired tonnage, it will be necessary to manipulate the control to place the valve element 34 in the position, shown in Fig. 4, wherein groove 54 no longer communicates with the pressure port 23. At this time, all of the fluid exhausted from the lower end of the power cylinder will be directed through

ports

55, 58, and 51, to the exhaust port 21. lf valve 59 is then in position to resist communication between

passages

56 and 51, a fluid pressure will be generated in passage 55, port and in the lower end of the power cylinder well as in other communicating passages. rfhis pressure will be admitted through port 55 to the under side of the now-directing spool 55 to again cause this spool to move in an upward direction as illustrated in Fig. 4, in opposition to the spring 44. If spool 50 moves upward a suilicient distance a portion of ports 48 will be exposed to by-pass a portion of the fluid admitted from the pressure source to exhaust causing the rate of movement of the ram to be reduced, the amount of fluid thus by-passed will be determined by the setting of theknob 14|. If the knob 4i is adjusted to move valve 59 outwardly relative to bore 58 the rate of communication between

ports

56 and 51 will be increased, the back pressure will be decreased, spool 59 will be lowered and less uid will be Icy-passed, the rate of ram movement being nearer the maximum possible controlled rate than if the knob is adjusted to move the valve 59 further into the bore 58. It should be obvious that the rate of ram movement during the actual pressing operation may be controlled at will through the adjustment of knob 4I.

After the ram has completed the pressing stroke, that is, when it has met an obstruction which offers suflicient resistance to movement of the ram to cause the main relief valve 66 of the hydraulic system to open, iluid flow from the pressure source to the upper end of the power cylinder will stop and fluid will cease to be exhausted from the lower end of the power cylinder, the back pressure caused by the resistance to flow oiered by valve 56 will then be dissipated and spring 44 will return spool 5U to the position where communication between

ports

41 and 43 will be interrupted, At this time the ram will be exerting the maximum tonnage for which the main relief valve 6G has previously been adjusted. As long as valve element 34 is maintained in the position shown in Fig. 4 and the flow-directing spool 50 is in its lowermost position this maximum tonnage will be exerted by the ram.

When it is desired to retract the ram from the work the valve element 34 is moved to the position shown in Fig. 5. In this position ports 45 are located in registration with the bottom cylinder port 25 and fluid may then flow from the pressure port 23 through ports 4l, through the groove 53 and outwardly through ports 45 to the bottom cylinder port 25 from which it will flow to the lower end of the power cylinder. The force of this fluid exerted on the under side of the piston in the cylinder will cause the piston to move in an upward direction and fluid will be exhausted from the upper end of the power cylinder to port 24 from which it will flow through ports 48, the interior of chamber 35 above spool 50 and outwardly through ports 49 to the exhaust port 26, this fluid then flowing to the reservoir. The ram will continue in its upward movement until an arm 6|, on the ram engages a collar 62 on the shipper rod causing the shipper rod and valve element 34 to move in an upward direction until registration of ports 45 with recess 25 is interrupted at which time the flow of pressure fluid to the lower end of the power cylinder will be terminated; the ram will then be in its retracted, inactive position. Subsequent cycles of ram operation may be performed by repeating the operations of the valve mechanism just described.

The mechanism shown in this application differs from that shown in my copending application, by the relocation of the groove 54 in the exterior of the valve element 34 thus providing for the differential of effective piston area and the rapid movement of the ram while approaching the work. With this groove located as illustrated in the dra-wings of the present application, fluid exhausted from the power cylinder can be combined with fluid admitted from the pressure source to cause the ram of the power cylinder to move at a more rapid rate.

With the new form of apparatus shown in this application, the mechanism can also be caused to operate as a reduced pressure relief valve as described, preventing the pressure gauge disposed in the system from giving an inaccurate indication of the pressure existing in the system.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow:

I claim:

1. Fluid flow control mechanism comprising a casing having a chamber with inlet, exhaust and first and second work ports spaced longitudinally thereof; a valve element disposed for movement in said chamber to establish communication between predetermined ports, said element having an internal chamber and a plurality of longitudinally spaced sets of lateral ports extending therefrom; recess means in said element operative in one position of said element to establish communication between said inlet port and said first work port, certain ports in said element establishing at the same time communication between said inlet port and the second work port; passage means in said valve element operative in a second position of said valve element to establish communication between said first work port and an exhaust port, ports in said element being operative in the second position of said element to continue communication between said inlet port and said second work port; means in said valve element for throttllng fluid flow through said passage means to create a fluid pressure; and a fiow directing member disposed in the chamber in said valve element and responsive to the fluid pressure to establish controlled communication between the second work port and an exhaust port when said valve element is in the second position.

2. Fluid flow control mechanism comprising a casing having a bore; a pressure port; an exhaust port on either side of said pressure port and first and second cylinder ports between said pressure port and said exhaust ports, all said ports communicating with said bore; a valve element disposed for sliding movement in said bore, said element having an internal chamber; passage forming means in said element operative in one position thereof to connect said pressure port with both cylinder ports; additional passage-forming means in said element operative in another position thereof to establish communication between said pressure port and said first cylinder port and between said second cylinder port and an exhaust port; valve means carried by said valve element and cooperating with said additional passage forming means to control fluid flow from said second cylinder port to exhaust port; a flow-directing member disposed for movement in said internal chamber; and passage means in said valve element to apply fluid at the pressure of said second cylinder port to said flow-directing member to move the same to a position to establish communication between said first cylinder port and exhaust while said cylinder port is connected with said pressure port.

3. Fluid flow control mechanism comprising a four-way valve having a casing with an inlet port, first and second work ports and exhaust ports; a pair of valve members disposed for movement in said casing to control communication between certain of said ports, said valve members being movable relative to said casing and to one another; passage means formed by said valve members and casing in one of the relative positions thereof to establish communica; tion between said inlet and both of said work ports; and additional passage means provided in one of said valve members for applying fluid of inlet port pressure to one of said valve members to establish communication between one of said work ports and an exhaust port while communication between said inlet port and both of said work ports is maintained.

4. Fluid flow control mechanism comprising a four-way valve having a casing with an inlet port, rst and second work ports and exhaust ports; a pair of valve members disposed for movement in said casing to control communication between certain of said ports, said valve members being movable relative to said casing and to one another; passage means formed by said valve members and casing in one of the relative positions thereof to establish communication between said inlet and both of said work ports; yieldable means between the valve members of said pair tending to maintain the relative positions thereof; and additional passage means provided in one of said valve members for applying fluid pressure to one of said valve members to move the same in opposition to said yieldable means to a position establishingcommunication between one of said work ports and an exhaust port.

5. Fluid flow control mechanism comprising a four-Way valve having a casing with an inlet port, first and second work ports and exhaust ports; a pair of valve members disposed for movement in said casing to control communication between certain of said ports, said valve members being movable relative to said casing and to one another; a first passage means formed by said valve members and casing in one of the relative positions thereof to establish communication between said inlet and both of said work ports; a second passage means provided in one of said valve members for applying uid at inlet port pressure to one of said valve members to move it to a position to establish communication between one of said work ports and an exhaust port While communication between said inlet port and both work ports is maintained; and a third passage means formed by said valve members in another of the relative positions thereof to establish communication between one of the work ports and said inlet port and between the other work port and an exhaust port, said second passage means then providing for the application of fluid, at the pressure of the work port communicating with the exhaust, to one of said valve members to move it to a position to establish communication between the other work port and exhaust while such work port is connected with the inlet port.

6. Fluid flow control mechanism comprising a four-way valve having a casing with an inlet port, rst and second work ports and exhaust ports; a pair of valve members disposed for movement in said casing to control communication between certain of said ports, said valve members being movable relative to said casing and to one another; a first passage means formed by said valve members and casing in one of the relative positions thereof to establish communication between said inlet and both of said work ports; yieldable means between the valve members of said pair tending to maintain the relative positions thereof; a second passage means provided in one of said valve members for applying uid at inlet port pressure to one of said valve members to move it in opposition to said yieldable means to a position to establish communication between one of said work ports and an exhaust port while communication between said inlet port and both work ports is maintained; and a third passage means formed by said valve members in another of the relative positions thereof to establish communication between one of the work ports and said inlet port and between the other work port and an exhaust port, said second passage means then providing for the application of fluid, at the pressure of the work port communicating with the exhaust, to one of said valve members to move it to a position to establish communication between the other work port and exhaust while such work port is connected with the inlet port.

'7. Fluid 110W control mechanism comprising a casing with a bore and inlet, exhaust and first and second Work ports communicating therewith; spool means disposed for movement in said bore; and passageways formed in said spool to connect certain combinations of ports in said casing in certain relative positions of said spool means and casing, said passageways serving in one relative position of said spool and casing to connect said inlet to one work and one exhaust port, another relative position of the spool and casing causing the passageways to provide for fluid flow from the second work port to the inlet and from the latter to the rst Work port, another relative position establishing fluid flow from said inlet to said rst Work port and from the second work port to exhaust and still another relative position serving to connect said inlet and said second work port and said rst Work port and exhaust.

8. Fluid flow control mechanism comprising a four-way valve having a casing with an inlet port, rst and second work ports and exhaust ports; inner and outer valve members disposed for movement in said casing to control communication between certain of said ports, said valve members being movable relative to said casing and one another; and passage means formed by said valve members and casing in one of the relative positions thereof to establish uid flow from one work port to said inlet and from said inlet to the other Work port.

CECIL E. ADAMS.

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

UNITED STATES PATENTS Number Name Date 1,775,856 Hauser Sept. 16, 1930 2,295,948 Henry Sept. 15, 1942 2,312,686 Campbell May 2, 1943