US3159375A

US3159375A - Flow control valve

Info

Publication number: US3159375A
Application number: US198939A
Authority: US
Inventors: Richard K Schrecongost; Joel A Jannenga
Original assignee: Greenlee Brothers and Co
Current assignee: Greenlee Brothers and Co
Priority date: 1962-05-31
Filing date: 1962-05-31
Publication date: 1964-12-01
Anticipated expiration: 1981-12-01

Description

Dec- 1, 1964 R. K. scHREcoNGos-r ETAL 3,159,375

FLow CONTROL VALVE Filed May 31. 1962 I5 Sheets-Sheet 1 OQTToraMaYf Bec. l, 1964 R, K. scHREcoNGosT ETAL 3,159,375

FLow CONTROL. VALVE Filed May 31, 1962 :5 sheets-sheet 2 Dec. 1, 1964 R. K. scHREcoNGosT ETAL 3,159,375

FLOW CONTROL VALVE .'5 Sheets-Sheet 3 Filed May 31, 1962 United States Patent O pas 3,159,375 FLDW CNTRL VALVE a Richard K. Schrecongost and .Foei A. .lannangm Rotentrord, lll., assignors to Greenlee Bres. fr Se., Rockford, ill., a corporation of illinois Filed May 3l, 1h62, Ser. No. 198,939 2 Claims. (Qi. 25E-31) The invention relates to hydraulic ilow control valves of the type which may be used in die-casting machines to control the stroke of a hydraulically actuated injection plunger.

The primary object of the present invention is to provide a novel valve of the above character with which the plunger velocity during the injection stroke may be increased in a plurality of precisely controlled and adjustable steps preselected according to the characteristics of the metal being cast and the size and shape of the die cavity being used.

Another object is to provide a unitary ilow control valve capable of initially accelerating the plunger at a controlled rate until the metal cylinder has been closed, advancing the plunger into the metal cylinder at a selected constant velocity during. the die-filling portion of the inject1on stroke thereby providing a steady flow of metal into the die, and sharply accelerating the plunger at a preselected iinal rate so that the plunger closes at high speed.

The invention also resides in the novel construction and mounting of the valve operator whereby the steps in the valves opening may be adjusted precisely as desired and independently of each other so that the plunger speed and acceleration during each step may be selected exactly to tit the characteristics oi the metal and the die.

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

FIGURE 1 is a fragmentary elevational view of parts of a die-casting machine embodying the novel features of the present invention with part of the dies and the injection cylinder broken away and shown in section.

FIG. 2 is an enlarged fragmentary end elevation of the control valve assembly.

FIG. 3 is a fragmentary sectional view taken along the line 3-3 in FIG. 2.

FIG. 4 is a diagrammatic view showing the hydraulic circuit of the die-casting machine.

FlG. 5 is a graphic representation of the velocity of the plunger during dii'rerent portions of the injection stroke.

As shown in the drawings for purposes of illustration, the invention is incorporated in a die-casting machine for injecting molten metal into a mold and holding the metal under pressure as it solidiics, the mold being formed between two die members lil releasably clamped together in a manner well known in the art. -The illustrative machine is of the cold chamber type in which the metal is ladled through a port or well lll into a bore 1.2 forming the metal cylinder leading to the die cavity, and a hydraulically actuated plunger i3 slides back and forth in the bore to force the metal into the die cavity.

The plunger 13 is carried by a piston 14 tted in an injection or shot cylinder l5 axially alined with the bore 12. To reciprocate the plunger, pressure fluid is delivered alternately to opposite ends of the cylinder l5 from a suitable source, herein an accumulator 17 of conventional construction and operation charged by a hydraulic pump (not shown) and capable of storing a large volume of oil under pressure vfor delivery to the injection cylinder. Connecting the accumulator to the head end of the cylinder l5 is a passage deiined by pipes 1.8 and 19 (FlG. l), and interposed in the passage is a valve assembly 2t) for Finally, as the plunger approaches the end of its stroke,

li Patented Dec. l, 1964 selectively opening and closing the passage to operate the plunger.

Herein, the valve assembly Ztl includes a generally cylindrical Valve head 2l slidable back and forth between an open position and a closed position in a cylindrical chamber 22 formed in a valve body 23, the chamber havinfr an inlet port Z4 through one side communicating with the accumulator and an open end 25 forming an outlet port connected to the pipe i9 leading to the injection cylinder. Ahelically coiled compression spring 27 is conned in the chamber 22 between the closed end 2S thereof and the valve to urge the latter toward the port 21S so that a nozzle end 29 of the valve extends into the port 25 amd an annular beveled shoulder 3) encircling the valve seats in the outlet. When the valve is in this closed position (FIG. 3), oil is pumped into the accumulator through an annular chamber 31 around the valve communicating between the inlet port 24 and a conduit 32 leading to the pump.

After a charge of metal has been introduced into the bore, the valve 2l is shifted to the right, as viewed in FIG. 3, to open the

ports

24 and 25 and permit oil to flow from the accumulator into the injection cylinder 15 and shoot the plunger 13 into the bore l2 and past the well lll, closing the latter and forcing the metal into the die. The nozzle may be grooved 'as at 33 (FIG..3) to obtain a controlled ilow through the port 25. vTo retract the plunger and open the well for the next charge of metal, oil is directed into the rod end of the cylinder l5 through a line 3d. The dies are opened for removal of the completed casting and then closed for the next' injection stroke of the plunger.

The present invention contemplates a novel valve assembly Zil for opening the passage between the accumulator and the injection cylinder in a plurality of controlled steps whereby the velocity and acceleration of the plunger i3 during dierent portions of the injection stroke may be preselected according to the characteristics of the metal being cast and the shape and size of the casting. For this purpose, the valve assembly 2i) includes a hydraulic valve actuator capable of moving the valve 2l rstat a controlled rate of travel into a preselected partially open position thereby steadily increasing the rate of iiow of oil into the cylinder l5 and correspondingly accelerating the plunger at a preselected and controlled rate until the well is closed. Then, by leaving the valve in the partially open position, the plunger may be advanced for a short period at a constant rate to provide a steady, -predetermined iiow of tluid metal into the die cavity to ll the latter at a rate adapted to the type of metal and die.

the valve may be moved farther toward the open position, again ata preselected rate of travel and again increasing the rate of flow to the injection cylinder to accelerate the plunger. This iinal acceleration may be at a greatly increased rate to impart a high closing velocity to the plunger. Also, the valve may be stopped short of the fully open position to control the final plunger velocity.

To achieve these ends, the valve actuator includes a reciprocating element, herein a piston 3'7slidable in a .cylinder 3S, connected to the valve to shift the latter toward the open position, and pressure means including v iiow control means isprovided to regulate the rate of travel of the piston 3'7 and, therefore, to control the rate of acceleration of the plunger i3. A stop member 39 is disposed in a preselected blocking position to block sliding o the piston 37 when the latter has moved the valve to the partially open position, the stop 39 thus determining the velocity of the plunger during the filling portion of the stroke. Selectively operable means is provided to move the stop out of the blocking position when the plunger approaches the end of its stroke so that 'thepiston 37 vmoves the valve past the partially open position thereby to increase the iiow of oil to the plunger and shoot the latter forward at high'speed. Preferably, a first flow controller il regulates the initial plunger ac- Celera-tion and a' second flow controller al, activated when the stop 39 is moved, controls the iinal rate of travel of thepiston 37 and thereby regulates the nal accclera- Y tion of Vthe plunger. A second stop 42 may be provided to block opening of the valve at a second predetermined point thereby determining the open position and the highest fluid flow Vduring'each injection stroke.

Herein, the cylinder 38 is formed in the valve body 23 adjacent the closed end 23 of the chamber 22 and preferably is coaxial with the chamber, and a rod 43 extending through rand journaledfor endwise sliding in the coinrnon wall V44 between the cylinder d8 and the chamber rigidly joins the'piston 37 and the valve for sliding back and forth in unison. The spring 27 is coiled around the rod 43 and urges the piston 37 into its normal, retracted Vpositioi'if'a`r'ija.ce'i:t the wall i4 and against the end of a collar integral with the wall 4d and encircling the rod to provide the bearing for the rod. Seal rings d encirclingv the rod within the bearing prevent oil leakage through the wall.

The pressure means lfor moving the valve toward the Open position at a controlled rate include, in this instance, a conduit 47 for delivering pilot pressure iluid to the cylinder 38 to move the piston 37 away from the end wall,

"'while pressure fluid trapped within the chamber 22 resists 'movement 'of the piston away from the wall, the iiow controller 40 comprising an adjustable needle valve interposed in a drain line 48 communicating with the chamber through conduit 49 to restrict the ow of vtrapped fluid 'from the chamber and thereby retard the movement of 'the piston 37 and valve 21'. By adjusting the needle to increase or decrease the ilow through the lines i9 and d, the rate of travel of the piston during this step and, ac- 'cording1y,A the acceleration of the plunger, are correspondingly increased or decreased. It will be apparent that lluid could be coniined within the head end of the cylinder 38 with the same result. In the illustrative embodiment, however, this end of the cylinder communicates with'the outlet port 25 through a vent line Sli extending through the rod to maintain a balance of pressure at oppositeends of the piston assembly.

Shown in FiG. 5 is a graphic representation illustrating one combination of steps obtainable with the novel Y valve assembly. In the graph, the vertical coordinate represents bothV the velocity -of the plunger and the volume of flow into the injection cylinder, the two being directly proportional. The initial acceleration is represented in FIG. 5 bythe slope of the line 51.

In this instance, a second hydraulic actuator comprising a piston rSZ slidable in a cylinder 53 disposed in endto-end relation with the cylinder 3S and preferably coaxial therewith is formed in the valve body 2x3 to provide rselectively operable means for moving the stop 39 into and out of its blocking position. As shown in the drawings, the stop may be formed by'a rod 54 extending through the partition 55 between the cylinders 3S and SS-and preferably fastened at one end to one of the pistons with the other end terminating adjacent the other piston,

the free 'endY thus coacting with the adjacentpiston to'i'orm.

theV stop 39. Herein, thefrod is secured 'to the vpiston 52 with the free end spaced a short distance from the piston `37 to abut against the latter and interrupt its movementV piston 37 at a second point.

der is maintained and the plunger is advanced at a constant Velocity, as indicated by the line 53 in FIG. 5.

Movement of the rod 5d out of the blocking position is accomplished by delivering oil under pressure to the rod end of the cylinder 53 through a conduit 59 thereby to shift the piston 52 to the right as viewed in FIGS. 3 and 4. The' second'flowcontroller il activated when the stop 59 ismoved out of its blocking position herein comprises a second needle valve interposed in a normally closed drain line olwhich is connected in parallel with the line 48 and is opened when the stop 39 is moved. To provide a rate of plunger acceleration different from the initial rate, the needleydl may be set to accommodate a greater volume of dow from the chamber 22 than does the needle dit. Accordingly, the piston 37 and valve 2l will move to the right at af'faster rate than before thereby completing the filling of the `die and compacting of the metal at high speed. When the needle 4l is left completely open, a sharp increase in plunger speed is obtained as indicated at di in FlG; 5. A different setting of the needle dll will eiiect an increase in acceleration greater than the initial rate yet less thanV instantaneous, this being indicated in phantom at e2. in the graph.

if the valve 2l is moved to the fully open position, the full capacity of the system will be delivered to the injection cylinder. l lf, on the other hand, a lower 'plunger speed than'the highest obtainable is called for by the characteristics of the metal and the die, opening of the valve may be limited by interrupting movement of the ln this instance, the stop 42 utilized for this purpose is formed by a rod 63 extending into the cylinder 53 through the rod end thereof and having a free 'end disposed adjacent and in thepath of the piston 52 to abut against the piston after the latter has shifted the stop 39 a predetermined distance away from the piston 37. in this'manner, the level of the line 64 (FIG. 5) is determined. i

The invention also contemplates constructing and mounting the valve actuator in a novel manner so that each of the steps inthe opening of the valve may be adjusted precisely as desired and independently of the other adjustments and, therefore, the plunger velocity during each portion of the injection stroke may be selected exactly to iit the characteristics of the particular metal and the die. To these ends, the piston 52 is adjustable relative to the piston 37 to adjust the stop 39 andV vary the stroke of the piston 37 thereby to select the partially open position of the valve 2l, and the stop d2 is adjustable toward and away from the piston 52 without disturbing the setting of the stop 39. l

For these purposes, the cylinders 3S and 53 are formed in a hollow, open-ended sleeve 65 divided intermediate its ends by a transverse wall forming the partition 55, and the sleeve is telescoped into a cylindrical recess o7 in the valve body so that Vthe inner end of the recess forms the end of the cylinder 3S against which-the piston 37 normally abuts. To adjust the stop?, means is provided to shift the sleeveV axially in the recess and maintain a selected position of the sleeve therein thereby to shift the partition and the piston 52 toward and-away from the piston 37. ln this instance, this means comprises threads 63 around the exterior of the sleeve and in the wall of the recess.

Turning of the sleeve to shift the stop k39 back and forth to adjust the stroke of the piston 37 may be accomplished conveniently by'a hand wheel o9 fixed to a hub 7o formed integrally with the outer end of the sleeve. To lock thesleeve in a selected position, a-collar '71 is telescoped loosely around the sleeve for abutment with the hubV and'is releasably secured to the sleeve by a radially extending pin 72 urged by a'spring 73 into one f of a plurality of bores 74 angularly spaced around the position. 'With the valve held in this position, a constant vvolume flow from the accumulator to the injection cylinsleeve. A knob '75 is provided to disengage the' pin thereby permitting turning 'of the sleeve relative -to the collar. rthe collar 7l isloclred against turning relative `lto the valve body by means of an axially extending dowel pin 77 with opposite ends seated in registering bores in the collar and in the body, the pin 77 being urged Itoward the collar by a compression spring 78 confined in the bore 79 in the body. Thus, as the sleeve is shifted in and out, the spring 7S extends and contracts to press the pin 77 into the collar and, therefore, holds the latter firmly against the hub 701.

As shown in FlG. 3, an indicating finger Sil may be fast on the body 23 to project axially over the collar 7l, and the latter may be marked with calibrations to indicate the amount of axial adjustment of the sleeve. When a desired adjustment has been made, the sleeve is locked in place by seating the pin 72 in the registering one of the bores 74 in the sleeve.

The passages S7 and 59 opening into the cylinder 53 on opposite sides of the piston 52 communicate respectively with axially spaced annular chambers Sl and 82 encircling the sleeve. These chambers are made of substantial axial width to maintain communication with conduits 83 and S4 in the valve body in any of the various axial positions of the sleeve relative to the body.

Closing the outer end of the sleeve 65 is a plug S5 telescoped into the sleeve and having an annular ange S7 for abutting against the hub 79 and receiving bolts 88 (FIG. 3) which are threaded into the hub to hold the plug SS in place. Thus, the inner end of the plug forms the end Wall at the head end of the cylinder 53. rl`hestop rod 63 extends axially through the plug and into the cylinder and herein is threaded at 89 in the plug thereby providing means for adjusting the stop d2 toward and away from the piston 52. A hand wheel du is keyed to the outer end of the rod 63 to facilitate turning of the latter, and a collar 91 (FIG. 3) is disposed around the rod and in abutment with the wheel @il This collar is releasably locked to the wheel by a pin 92 which may be disengaged by a knob 93, and a pin 9d locks the collar 91 against turning relative to the hub 76. A finger @5 extends over calibrations on the collar 9i to indicate thev amount of adjustment of the stop 42.

With this arrangement, the operator irst adjusts the stop 42 by disengaging the pin 92 and then turning the wheel in the appropriate direction until the end of the rod 63 is disposed the desired distance from the piston ,52. Then the -pin 92 `is locked in the collar 91 `and the position of the stop 42 is thereby fixed. Then the pin 72 is disengaged and the wheel e9 turned until the desired increment of change in the position of the stop 39 has been made, as indicated by the position or" the finger Sti relative to the collar 71. lt will be apparent that both the piston 52 and the stop 42 move in unison with the sleeve 65 thereby maintaining the first adjustment. When the pin 72 is locked in the sleeve, the strokes of the

pistons

37 and 52 are determined. The number of settings for each stop is limited only by the locking means, in this instance the spacing of the recesses engagedby the pins 72 and 92.

Operation The novel features of the present invention will be apparent from the following summary of the operation of the valve assembly above described as controlled by the hydraulic circuit shown in FIG. 4.

Initially, the stops 39 and 42 are adjusted as above described and the how-controlling needle valves d@ and 41 are set to provide the desired ow of trapped fluid from the chamber 22 during acceleration of the plunger. With the valve 2l closed, a Vsupply of fluid under pressure is stored in the accumulator 17 to operate the plunger'.

Herein, solenoid-operated pilot valves 9d and 97 are provided to control the operation of the valve actuator. As will be seen from FIG. 4, .pilot valve 95 controls the movements of the piston 37 and pilot waive @7 controls the piston 52. When the plunger is at rest, the solenoid 98 is de-energized and the spool 99 of valve 96 is springd urged to the left to connect the'conduit 49 to a pressure line lll@ through check valve lill, While the conduit 47 connects the cylinder 3S to the reservoir through drain lines N2 and 163. The spool 14M of de-energized solenoid j connecting pressure line ldd to the conduit i7 leading to v the rod-end of the cylinder 3S. At the same time, the chamber 22 is connected to the drain line 193 through the line iSv-controlled by the needle valve 4t?, the parallel line d0 being closed by the pilot valve 97. Thus, thehead 2l is moved toward the open position at a rate of travel determined by the settingof the needle 4? until the piston 37 abuts against the rod 54. Preferably, the stop 39 is positioned so that this occurs after the plunger i3 has closed the well ill. Thereafter and until the stop 39 is moved, the plunger advances into the bore at a constant velocity, yielding of the piston 52 being prevented by check valve lds in pilot pressure line ,lili

Means responsive to the position of the plunger preferably is provided to actuate the solenoid N7 for the'high speed shot. This means may comprise a switch (not shown) adjustably positioned to trip as the plunger reaches a predetermined point near the end of its stroke. When this happens, the spool ldd is shifted to the right to conneet pressure fluid to the rod end of the cylinder 53 through chamber '32 and conduit 591 thereby urging the piston 52 away from the piston 37 so that the latter is free to move the valve 2li past the selected partially open position. Simultaneously, parallel line d@ is connected to the drain and fluid from chamber 22 may ow past needle 4l as Well as needle di?. Thus, the setting of the needle-41 determines the new rate of Opening .of the valve 2l and the corresponding rate of plunger acceleration. The setting of the stop 42, of course, determines the amount of final opening of the valve 21. In a manner well known in the art, a pressure intensification system (not shown) may be utilized to obtain a final high-pressure compacting of the casting.

To withdraw the plunger i3 from the bore l2 and return y the

pistons

37, 52 to their retracted positions, both solenoids are cle-energized and pressure uid is directed through line 3ft to the rod end of the injection cylinder l5. Thus, the machine is in condition for the next injection stroke.

it will be apparent from the foregoing that the novel valve assembly provides a yunitary control of relatively simple construction and operation and effective to increase the velocity or the plunger in a plurality of precisely controlled steps which are adjustable to produce the Iwide range of combinations to tit the characteristics of the metal and die being used. The plunger may be accelerated initially at a controlled rate which effects rapid closing of the metal well without danger of splattering molten metal out of the chamber. Then, the constant velocity filling rolie rapidly fills the die cavity with a solid, steady flow of metal. Finally, the high speed shot at the end of the stroke completes rapid filling vof the die at a rate which may be selected according to the shape and size of the casting, uidity and temperature of the metal, and any other pertinent factors. rl'husJ the valve is adaptable to insure `proper control under a wide variety of different circumstances.

We claim as our invention: -l. A valve assembly including, in combination, a valve body, a hollow cylindrical sleeve threaded into a recess in said body, a partition dividing said sleeve intermediate .its ends into rst and second cylinders disposed in end-toend relation, first and second pistons slidable respectively in said cylinders, a valve movable back and forth in a ine conduit 3d to the pressure line liiS' and admit` passage between an open position Iand a closed position,

said valve being connected to said first piston whereby movement of the iatter in one direction shifts said valve toward said open position, a meinbersupported on one of said pistons and journaled in said partition to terminate adjacent the other of said pistons thereby forming a stop lfor blocking sliding of said first piston when said valve is in a partially open position, means for turning said sleeve into and out of said bodyt-o adjust the position of said stop relative to said pistonthereby to Vary said partially open position, a second member extending l through and threaded in one end of said sleeve to 1terminate adjacent and in the path of said second piston and form a second stop limiting sliding of the second pist-on away from said first piston yand thereby determining said open position, means for turning said second member int-o and ont of said sleeve to vary the position of said second stop relative to Said second piston, and rneansfor delivering pressure fluid to said Vfirst' cylinder to move said rst piston able back and forth .between an open position and a closed position, said valve being Vconnected to said' rst piston whereby movement of the latterrin one direction shifts said valve toward said open position, a member supported on one of said'pistons and extending through said partition to terminate adjacent tbev'oitller of said pistons thereby forming a stop for blockirigsliding o' said first piston when said valve is in a partially open position, means for delivering ressnre fluid to said iirst cylinder to move said first piston in said one direction .and said valve into said partialiy open position and .thereatter to said second cylinder to move said second piston away from said iirst piston, a second member supported on said sleeve' and disposed in the path of said second piston to form a second stop limiting sliding of the second piston away from said first piston, rneans adjustably positioning saidrsleeve .axially in said -body to vary Vthe position of said first stop relative to said first piston, and meansadjustably positioning said second member axially oflsad sleeve to vary the'position of said second stop relative to said second piston.

Whalen Sept. l2, 1933 1,956,906 vMileaelson 'May 1,1934 '2,765,898 Tydernan d Oct. 9, 1956

Claims

1. A VALVE ASSEMBLY INCLUDING IN COMBINATION, A VALVE BODY, A HOLLOW CYLINDRICAL SLEEVE THREADED INTO A RECESS IN SAID BODY, A PARTITION DIVIDING SAID SLEEVE INTERMEDIATE ITS ENDS INTO FIRST AND SECOND CYLINDERS DISPOSED IN END-TOEND RELATION, FIRST AND SECOND PISTONS SLIDABLE RESPECTIVELY IN SAID CYLINDERS, A VALVE MOVABLE BACK AND FORTH IN A PASSAGE BETWEEN AN OPEN POSITION AND A CLOSED POSITION, SAID VALVE BEING CONNECTED TO SAID FIRST PISTON WHEREBY MOVEMENT OF THE LATTER IN ONE DIRECTION SHIFTS SAID VALVE TOWARD SAID OPEN POSITION, A MEMBER SUPPORTED ON ONE OF SAID PISTONS AND JOURNALED IN SAID PARTITION TO TERMINATE ADJACENT THE OTHER OF SAID PISTONS THEREBY FORMING A STOP FOR BLOCKING SLIDING OF SAID FIRST PISTON WHEN SAID VALVE IS IN A PARTIALLY OPEN POSITION, MEANS FOR TURNING SAID SLEEVE INTO AND OUT OF SAID BODY TO ADJUST THE POSITION OF SAID STOP RELATIVE TO SAID PISTON THEREBY TO VARY SAID PARTIALLY OPEN POSITION, A SECOND MEMBER EXTENDING THROUGH AND THREADED IN ONE END OF SAID SLEEVE TO TERMINATE ADJACENT AND IN THE PATH OF SAID SECOND PISTON AND FORM A SECOND STOP LIMITING SLIDING OF THE SECOND PISTON AWAY FROM SAID FIRST PISTON AND THEREBY DETERMINING SAID OPEN POSITION, MEANS FOR TURNING SAID SECOND MEMBER INTO AND OUT OF SAID SLEEVE TO VARY THE POSITION OF SAID SECOND STOP RELATIVE TO SAID SECOND PISTON, AND MEANS FOR DELIVERING PRESSURE FLUID TO SAID FIRST CYLINDER TO MOVE SAID PISTON AGAINST SAID FIRST STOP AND THEREAFTER TO SAID SECOND CYLINDER TO MOVE SAID SECOND PISTON AGAINST SAID SECOND STOP WHEREBY SAID VALVE IS SHIFTED INTO SAID OPEN POSITION.