US2526800A - Combination surge check and release valve for hydraulic press-operating circuits - Google Patents

Description

Oct. 24, 1950 R. w. B'REHM El AL 2,526,800

. COMBINATION SURGE CHECK AND RELEASE VALVE FOR HYDRAULIC PRESS-OPERATING CIRCUITS Filed 06%. 28, 1948 2 Sheets-Sheet 1 I l awe/Mom F] P066722 Wfii'rf/zm Warren R Tucker Oct. 24, 1950 R. w. "BREHM .ET AL 2,526,800

- QOMBINATION SURGE CHECK AND RELEASE VALVE-; FOR HYDRAULIC PRESS-OPERATING CIRCUITS Filed Oct. 28, 1948 2 Sheets-Sheet 2 .56 42 a 7 /4 A 0 \\\\m (30 3 38 kg 2 c 25 l 4.9 49 Fl 6. 2 26 23 Warn '3 Patented Oct. 24, 1950 COMBINATION SURGE CHECK ANDRELEASE I VALVE FOR HYDRAULIC PRESS-OPERAT- ING CIRCUITS Robert William Brehm and Warren E. Tucker,

Mount Gilead, Ohio, assignors to H-P-M Development Corporation, Mount Gilead, Ohio, a

corporation of Delaware Application October 28, 1948, Serial No. 57,002

8 Claims. (01. 60-42) This invention relates to hydraulic press-operating circuits, the same havin particular reference to valve mechanism for controlling the admission and release of pressure fluid to the ram cylinder of a hydraulic press.

An object of the present invention is to provide a novel arrangement of a pressure-releasing valve means for preventing shock to the hydraulic system of the press through providing for a graduated release of pressure on the press .plunger before a major release of pressure takes place.

It is another object of the invention to pro- .vide an adjustable pressure relief valve for hydraulic press control systems by which variations are made possible for controlling the period of gradual pressure release before major pressure relief takes place.

A further object is to provide in a single valve assembly a combined surge-checking and pressure-releasing means, the assembly providin for simplification in mechanical design,,long operating life and positive operation. I

Other objects and advantages will become apparent from a reading of the following description when taken in connection with the accompanying drawings. In said drawings:

Fig. l is a diagrammatic view of a press-operating circuit, certain parts being shown in section and disclosing in said circuit the combined surgechecking and pressure-releasing valve. mechanism comprising the present invention;

Fig. 2 is an enlarged vertical sectional view taken through the surge-checking and pressurereleasing valve mechanism disclosing the same in one position of operation;

Fig. 3 is a similar view disclosing the valve mechanism of Fig. 2 in other operating positions;

Fig. 4 is a horizontal sectional view taken on the plane indicated by the line 4-4 of Fig. 2.

A particular embodiment of the invention is illustrated in the accompanying drawings which show a hydraulic press A of the downward pressure type adapted to be operated by means of a includes a base I, a press head 2 connected to reversible flow circuit including, in the present the base by vertical tie 'rods 3, and a platen 4 I ,mounted for reciprocatory movement on the tie rods. A main ram or plunger 5 is connected to the platen and is mounted for movement within a main cylinder 6 having a main pressing chamber 1.

ing'an internal chamber 22.

The pump B has one of its outlets 8 provided with a pipe line 9 which extends to the chamber 1 for producing fluid pressures within said chamber adequate to perform the work of the press. The outlet ID of the pump B is joined by a pipe line H which leads to the differential space I2 provided in the cylinder 6 below the head 5a of the ram 5.

A surge-checking and pressure-releasing valve D is provided for effecting relatively open com munication between the pressing chamber I of the main cylinder and the tank C.

The valve D, which comprises the present invention; is formed to include an outer casin l3.

This casing is formed with an annular horizon- .of the flange l4, hold the casing of the valve D in frictional clamping contact with the bottom wall ll of the tank C and also with a gasket l8 7 seated on an annular shoulder I9 provided in a vertical bore 20 formed in the upper end of the cylinder 6. I

The casing I3 .below the flange I4 includes a depending annular skirt 2| which is received in the bore 20, the skirt 2| defining within the cas- This chamber is capable of communicating with thechamber 1 of the cylinder 6 when the head of a main check valve'23 occupies an unseated position in spaced relation from the annular seat 24 formed on the lower end of the skirt 2|. The upper end of the chamber 22 communicates freely with the interior of the surge tank C by way of a plurality of open-ended ports shown at 25.

'Above' the flange M, the casing 13 is formed .with a hollow body 26 which includes an interthe body 26 includes a bore 29 in which is positioned for sliding movement the hollow stem 30 of the main-check valve 23.

- The .upper end of the stem 30 carries a piston 'head 3| which is'slidably mounted in the upper end of the chamber 21.

A coil spring 32 surrounds the hollow stem of the check valve 23 'andis confined between the under side of the head. 3| and the bottom of the chamber 21, the

spring 32 serving normally to maintain the peripheral edge of the conical outwardly flaring head 23 of the check valve in engagement with the seat 24. A port 34 establishes communication between the enlarged upper end of the chamber 21 and the interior of the surge tank C. Also the bore 29, midway of its length, is provided with an annular groove 35 which is adapted to register with transverse ports 36 formed in the valve stem 30. Above the ports 36, the valve stem is provided with additional ports 31, which provide for communication between the interior passage 38 of the valve stem and the chamber 21 and the port 34.

Slidably mounted in the passage 38 is a piston 39, the latter being formed at its upper end with a head 46 disposed for engagement with the walls of the passage 38 and at its lower end with a similar head 4|. Between the heads 40 and 4|, the piston is provided with a body 42 of re duced diameter as compared with that of the heads 49 and 4| whereby to provide a differential area 43 between the body 42 and the inner wall surfaces of the passage 38.

The upper head 40 is normally maintained in engagement with an annular shoulder 44 provided in or near the open upper end of the passage 38. Such engagement of the piston with the shoulder 44 is maintained normally by the provision of a coil spring 45. This spring is positioned so that its upper region engages with the under surface of the piston head 4|, while the lower portion of the spring 45 is seated in a socket 45 provided in a threaded plug 41 carried by the lower end of the valve passage 38.

While the piston 39 is normally positioned as shown in Fig. 2, the head 4| thereof is disposed in registration with an annular groove 48 provided in the valve passage 38. From the groove 48, there extends through the valve a plurality of downwardly diverging passages 49 which, at their lower ends, communicate with the pressing chamber 1 of the cylinder 6 but when the piston 39 is normally positioned have their upper ends closed by the lower piston head 4|.

Adapted to be secured to the top of the casing I3 is a removable cap ring 59. This ring is provided with countersunk openings for the reception of the headed ends of bolts or screws 52,

by which latter the ring is secured to the top of the casing. The gasket 53 may be utilized for sealing the joints between the ring and the valve body against fluid escape or pressure loss. The ring is formed with a threaded axial opening 54, which receives one end of a pipe line 55 forming a part of the return source of fluid pressure.

Communicating with the ports 36 is a passage 56 leading to a vertical valve bore 51, the passage 55 and bore 51 being formed in the material comprising the casing l3 of the valve assembly. The bore 51 includes a port 58 establishing communication with the interior of the surge tank C, the port 58 including a tapered valve seat 59. Cooperative with this seat and positioned in the port 58 is the tapered lower end of a valve member 60, the latter having a threaded body 6| which is received in the enlarged threaded upper end of the bore 51. The body 6| terminates at its upper end in a polygonal tool-receiving end 62 by which the valve 60 may be adjusted to vary the efiective area of the port 58 for fluid flow and to control the rate of escape of fluid traveling under pressure through the passages 56 into the tank C.

At the start of the forward or down stroke of the press ram or plunger 5, the suction created in the cylinder 6 by the weight of the moving parts of the press will cause the main check valve 23 to open and allow the cylinder 6 to pre-fill from the overhead oil reservoir. To do this, the suction has only to overcome the tension of the spring 32 which supports only the weights of the moving parts of the valve assembly. As soon as pressure develops in the cylinder 6 through contact with work or other means, it will cause the main check valve to close and remain closed during the pressing stroke or cycle operation of the press.

When the return stroke is begun, as soon as a pressure of, for example, pounds per square inch is developed in the pipe line 55, it will cause the inner plunger or piston 39 to move downwardly, against the resistance offered by the bottom spring 45, thus allowing oil to by-pass to the reservoir through the ports 31 and 34, the ports 3-1 being uncovered by the upper head 40 of the plunger or piston, 39. The main check valve 23 will remain stationary with its enlarged conical head in a seated position on seat 24 as a result of the pressure on the lower surface of its head applied from within the cylinder 6. With the inner piston or plunger 39 in a position opening the ports 31, oil under pressure from the cylinder 6 will through pump operation pass through the passages 49, which have their inner ends uncovered by the lowering of the piston 39. The oil traveling through the passages in the enlarged lower end of the valve 23 enters the differential area 43 and thence through the ports 36 into the passages 56, which conduct the fluid under pressure to the adjustable choke provided by the valve member 60. By adjusting this member, it is possible to determine the speed by which the pressure is released from the cylinder 6 in order to prevent shock to the hydraulic system. The oil passes through the choke or valve member and its associated port 58 and is exhausted into the surge tank C.

When the pressure has been released from the cylinder 6 through this restricted means of escape to a point where it is about two-fifths the pressure present in the pipe line 55 leading to the opening 54, the pressure in said pipe line will cause the entire main check valve 23 to move downwardly a determined stroke. In so doing, the ports 34 will be closed by the upper head of the piston or plunger 3|, which will prevent the oil flowing into the upper end of the mechanism from by-passing to the tank, and check valve 23 will consequently be held in its down position, as indicated in Fig. 3; Also the ports 36 will be blocked and the choke valve 60 will therefore be inactive. In this down position, the check valve 23 will have moved downward from its lower seat and the remaining oil in the cylinder 6 will flow around the check valve and exhaust rapidly to the surge tank or reservoir through the ports 25 in the valve casing. The check valve 23 will remain in this down position through the remainder of the return stroke of the press, and provide a rapid exhaust for the oil in the cylinder. At the completion of the return stroke, the pressure in the line-55 will be removed, and the springs 32 and 45 will return the check valve 23 and its inner plunger or piston 39 to their elevated or original positions.

From the foregoing, it will be apparent that in accordance with our invention, it is possible to obtain a more rapid release of pressure from the main cylinder than has heretofore been possible and consequently the operating speed of the press is increased. By virtue of the adjustable choke valve 60, it is possible to regulate the operating speed without varying the rate of discharge of the pump. The form of the invention shown and described herein is considered as a preferred embodiment of the invention, but it will be understood that various modifications and changes may be made in the actual structure disclosed without departing from the spirit of the invention as defined in the following claims.

' We claim:

1. A combined surge check and release valve mechanism for hydraulic pressure systems, comprising: A casing formed for attachment to the head of an associated cylinder into which a fluid'is 1 introduced under pressure to effect the operation of a piston, said casing having an internal chamber; a main check valve slidably mounted in said chamber; spring means acting on said check valve to maintain the same normally in a position closing an end of said chamber communicating with the interior of said cylinder, whereby to prevent normally passage of fluid under pressure from said cylinder and into said chamber for discharge through a main port formed in the walls of said casing and leading from said chamber to a source of fluid supply; a high pressure fluid passage formed in said casing and check valve and leading from the cylinder to said fluid source, a plunger slidably mounted in said main check valve, spring means maintaining said plunger normally in a position closing said passage, and means for introducing a fluid under pressure into said chamber in a direction opposing the forces exercised on said check valve and said plunger by said spring means, whereby to, lfirst, move said plunger to a position providing for a restricted flow of fluid from said cylinder to the source of supply through said passage and, second, follow.- ing predetermined fluid flow, and consequent re-' .duction of fluid pressure in said cylindento unseat the check valve member and cause the direct flow of fluid from said cylinder to the supply source by way of said port.

2. A combined surge check and release valve mechanism for hydraulic pressure systems as defined in claim 1 in combination with an adjustable choke valve for regulating the outflow of fluid from said high pressure passage.

3. A combined surge-checking and pressurereleasing valve mechanism for hydraulic pressure systems, comprising: a casing formed internally with a valve chamber, said chamber communicating at one end with the interior of an associated cylinder adapted to receive fluid under pressure, a, fluid reservoir disposed above said cylinder, the walls of said casing being formed with a main port establishing communication between said chamber and said reservoir, a check valve movably mounted in said chamber, biasing means operating on said valve to maintain the same in a position obstructing fluid flow between said cylinder and said reservoir, a high pressure fluid passage formed in the walls of said casing and check valve and establishing a supplementary path of fluid travel between the interior of said cylinder and said reservoir, a slidable plunger member positioned in said check valve, biasing means operating on said plunger member for maintaining the same normally in a position obstructing fluid flow through said passage, and means for introducing a fluid under pressure into said casing in a manner to counteract the influence of said biasing means thereon, whereby to move said check valve and plunger member to positions in which the plunger member is first actuated to provide for fluid flow through said passage and, secondly, the opening of said check valve for a. more unobstructed passage of fluid to said reservoir than is permitted by fluid travel through said passage.

4, A combined surge-checking and pressurerel'easing valve mechanism for hydraulic pressure systems, comprising: a main cylinder having ahead formed with a socket opening; a piston slidably mounted in said cylinder; reversible pump means for introducing a fluid under pressure into said cylinder for controlling the direction of sliding movement of the piston therein; a tank containing a working fluid arranged above said :ylinder; a valve casing having one end thereof positioned in the socket of said cylinder; the body of said casing being disposed within said tank; said casing being formed with an internal chamber communicating with said surge tank by means of a port; a. movable spring-biased check valve carried by said casing and normally serving to obstruct fluid flow from said cylinder through said port and into said tank; a restricted passageway formed in conjunction with said casing providing for the travel of fluid from said cylinder to said tank in a manner by-passing said check valve and port; a spring-biased plunger member movably mounted in said checkvalve and normally positioned to obstruct said high pressure passage; and means for introducing said fluid under pressure into said casing in a direction to, first, move said plunger member against the influence of its biasing means to a position providing for fluid travel from said cylinder to said tank by way of said passage, and following a predetermined flow of fluid through said passage and consequent reduction of pressure of the fluid in said cylinder to admit of the opening of said check valve, whereby to uncover said port and provide for a more unobstructed flow of fluid from said cylinder into said tank than that permitted to take place through said passage.

'5. A combination surge-checking and pressurereleasing valve mechanism as defined in claim 4. and wherein said passage is provided with an outlet having an adjustable throttle valve disposed for cooperation therewith.

6. A combination surge-check and pressurerelease valve comprising a casing having an axial bore provided at one end with a pressure inlet and at its opposite end with a valve seat region; a first low pressure passage extending through the walls of said casing and communicating with the bore thereof a distance inwardly of the valve seat region; a second high pressure passage extending through the walls of said casing and intersecting the bore intermediate the ends thereof; a tubular valve member slidably carried within the bore of said casing and provided at one end with a pressure-responsive area in communication with the pressure inlet of said casing and at its opposite end with a second pressure responsive area providing a relatively enlarged valve head for seating engagement with the valve seat region of said casing, said tubular valve member being formed with an axial bore communicating at one end with the pressure inlet of said casing; channel means extending through the valve head of said tubular valve member and communicating with the axial bore thereof; a port formed in said tubular valve member and arranged to register with the high pressure passage of said casing; spring means interposed between said casing and said tubular valve memher for urging the enlarged valve head into seat-' ing engagement with the valve seat region of said casing, the port of said tubular valve member, when the latter occupies its seated position, establishing communication between the bore of said tubular valve member and the high pressure passage of said casing; and a second valve member slidably carried within the bore of said tubular valve member and arranged to normally interrupt communication between the channel means formed in the valve head of said tubular valve member and the bore thereof, said second valve member being formed with a pressure-re sponsive area in communication with the pressure inlet of said casing and being movable in response to the introduction of pressure fluid within the pressure inlet of said casing to a position establishing communication between the channel means of said valve head, the bore of said tubular valve member, and the port formed in said tubular valve member.

7. In combination, a difierential hydraulic motor having a ram-advancing area and a ramretracting area; a fluid reservoir; pump means for supplying pressure fluid to either the ramadvancing or ram-retracting area of said motor; a casing connected with said motor and formed with a valve chamber arranged to communicate with the ram-advancing area of said motor and provided with a pressure inlet; a first channel means in said casing hydraulically connecting said valve chamber and said reservoir; a second channel means in said casing providing for restricted fluid flow between said chamber and said reservoir; means hydraulically connecting the pressure inlet of said chamber with the ramretracting area of said motor; valve means movable to connect or disconnect said valve chamber and the ram-advancing area of said motor; and fluid-pressure-responsive means communicating with the pressure inlet of said chamber and responsive to positive fluid pressures within the ram-retracting area of said motor for first establishing restricted flow of fluid from the ramadvancing area of said motor to said reservoir by way of said second channel means and for thereafter unseating said valve means to permit substantially unrestricted flow of fluid from the ram-advancing area of said motor to said reservoir by way of said first channel means.

8. In combination, a differential hydraulic motor having a ram-advancing area and a ramretracting area; a fluid reservoir; pump means for supplying pressure fluid to either the ramadvancing or ram-retracting area of said motor; means connected between said reservoir and the ram-advancing area of said motor and responsive to a relatively low differential in pressures within the ram-advancing and ram-retracting areas of said motor to first establish a relatively restricted exhaust flow of fluid from the ram-adl vancing area of said motor and for thereafter establishing substantially unrestricted flow o1 fluid from the ram-advancing area of said motor to said reservoir, said last named means comprising a casing formed with an internal valve chamber arranged for communication with the ram-advancing area of said motor; channel means connecting the valve chamber with said reservoir, an axial bore forming a continuation of said valve member, and other channel means connecting the bore intermediate its ends with said reservoir; means in said other channel means for restricting the flow of fluid therethrough; a tubular valve member reciprocable in the bore of said casing and formed at one end with a relatively enlarged valve head normally arranged to interrupt communication between the ram-advancing area of said motor and the valve cham ber of said casing, said valve member being formed at its opposite end with a pressure-responsive area; passage means formed in said valve member and communicating at one end with the ram-advancing area of said motor and at its opposite end with said other channel means; fiuid-pressure-responsive means in said valve member tocontrol the flow of fluid through said passage means, said fiuid-pressure-responsive means being normally positioned to prevent the passage of fluid through said passage means; and means hydraulically connecting the fluidpressure-responsive area of said valve member and said fluid-pressure-responsive means with the ram-retracting area of said motor, said fluidpressure-responsive means being movable in response to a predetermined high pressure within the ram-retracting area of said motor to a position within said valve member permitting relatively restricted fluid flow between the ram-advancing area of said'motor and said reservoir, said valve member being movable in the bore of said casing in response to a predetermined flow of fluid from the ram-advancing area of said motor to said reservoir by way of said passage means and said other channel means to a position connecting the ram-advancing area of said motor with the valve chamber of said casing.

ROBERT l/VILLIAM BREHM. WARREN R. TUCKER.

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

UNITED STATES PATENTS Number Name Date 2,185,402 Dinzl Jan. 2, 1940 2,403,391 Muir July 2, 1946 2,410,869 Ernst Nov. 12, 1946 2,437,077 Cole Mar. 2, 1948 2,449,401 Lindsey Sept. 14, 1948

Images