US2193248A - Surge valve - Google Patents

Description

W. ERNST SURGE VALVE March 12, 1940.

2 Sheets-Sheet l Original Filed May 27, 1936 I Y i :INVENTOR. Man-7e FQ/VJT A TTORNEYS.

March 12, 1940. w. ERNST 2,193,248

' SURGE VALVE Original Fil ed May 27, 1936 2 Sh eets-S h eet 2 Java! P32 ifi 12a 1 A TTORNEYS.

Patented Mar. 12, 1940 {UNITED STATES PATENT orrrca SURGE vA'Lvn Walter'Ernst, Mount Gilead, Ohio, assignor to TheHydraulic Press Corporation, Inc., Mount Gilead, Ohio, a corporation of Delaware Original application May 27, 1936, Serial No.

Divided and this application February -25, 1937, Serial No. 127,799

3 Claims.

with a control circuit including this special valve arranged to prevent the building up of pressure in the main cylinder until the clamping plunger has engaged the work-piece.

Another object is to provide a special valve for such a press and circuit, wherein this special valve is arranged to prevent the main plunger from starting the drawing operation until the clamping plunger has engaged the work-piece with a sufiicient pressure.

Another object is to provide a surge valve for such a press and circuit, wherein this surge valve is provided with forcible opening and closing means arranged to permit the main plunger to carry out the drawing. operation as soon as a predetermined pressure has been built 'up in the clamping plunger cylinder by the engagement of the clamping plunger with the work-piece,

Another object is to provide a surge valve hav- 1:, ing a disabling device for temporarily and selectively holding the valve inoperative.

.Another object is to provide a special surge valve for use with a double-acting drawing press having a drawing plunger and clamping plunger,

with a hydraulic circuit and devices arranged topermit the gravitational descent of the clamping plunger and drawing plunger in exact unison with one another; this special surge valve being arranged to delay the application of pressure to the drawing plungerv until the pressure has been built up to a predetermined amount in the clamping. plung'er cylinder, whereupon ,the drawing plunger is permitted to carry out its drawing operation; this special surge valve being also ar- .-m ranged to release the pressure in the drawing plunger cylinder in response to the reversal of the main plunger;

This application is a division of my application filed May 27, 1936, Serial'No. 82,087.

45 In the drawings:

Figure 1 is a diagrammatic view, partly in section, of a hydraulic drawing press andcircuit, in connection with which the surge valve of the present invention may be used.

so Figure 2 is a central vertical section through the combination relief and check valve employed in the circuit of Figure 1.

Figure 3 is an elevation, partly in section, of the hydraulic pump used in the circuit of Figure 55 1, showing the servomotor control arrangement surge valve temporarily inoperative.

'a check valve IS, a pressure release valve H which (Cl. lat-153) for bringing about its reversal in response to the application of pressure fluid from an outside source.

-Figure 4 is an enlarged sectional view of the main cylinder surge valve of this invention, as 5 shown in Figure l.

Hydraulic press and circuit generally Referring to the drawings in detail, Figure 1 10 shows, for purposes of illustration, a circuit containing a hydraulic drawing press and associated control devices with which the surge valve of this invention may be used. The'circuit as a whole contains a number of individual units which may be generally designated before being described in detail. The press II] is operated by a main pump H, which in turn, is supplied with servomotor fluid from a servomotor pump l2, and dischargesfluid into the return side of the press 20 ID by way of the combination relief andcheck valve IS. The press H1 is also provided with a main surge valve. M, of a special construction according to the present invention, and having means incorporated therewith for holding the 25 The press II) is provided with clamping cylinders having a surge valve I5 opening into the surge tank of the press 10. The surge valve I5 is opened by pressure fluid from the push-back side of the main plunger, and is of a type described in the Ernst patent, No. 1,892,568, of December 27, 1932.

The surge tank of the press II! also contains is arranged to control direct communication between the main cylinder and the surge tank, and a by-pass valve 18, each of these valves being provided with choke valves 19 and 29, respectively. The details of the valves l1, I8, l9 and 20 form 40 no part of the present invention, but are fully disclosed in the Ernst patent, No. 1,956,758, dated May 1, 1934. The purpose of the main cylinder release and by-pass valve arrangement ll, 18 is to release pressure from the main cylinder prior 'to the opening 'of the surge valve and bypass the return of the pump discharge to the surge tank during the release of this fluid, in themanner described in the Ernst patent, No. 1,956,758. The circuit of Figure-1 also contains 5 an auxiliary or clamping pump 2|, arranged to provide pressure fluid for operatingthe clamping cylinders of the press. This clamping pump 2| is provided with a special servomotor control ar- Press construction The hydraulic press flflshown diagrammatically in Figure l is provided with aclamping block 22 having a die 23, with a recess 24 into which the work-piece 25 is to be drawn by the action of the press. upon the bed of the press (not shown) and is arranged to receive the outer portions of the work-piece 25, clamped thereagainst by the clamping slide 26. The clamping slide 26 is operated by the clamping plungers 21 adapted to reciprocate in clamping cylinders 28. The clamping slide 26, at points adjacent the junctions therewith of the clamping plungers 21, is provided with projecting portions 29 adapted to be engaged by the main platen of the press upon the upward stroke thereof, as will subsequently appear. Arranged to cooperate with the die 23 and adapted to fit-into the recess'24 thereof is a punch 30 attached to the main platen 3|, which in turn, is secured to the main or drawing plunger 32. The drawing plunger 32 is of a double-acting type, with a piston head 33, and reciprocates within the main cylinder 34.

' One of the clamping cylinders 28 is provided with an aperture 35 in the head thereof, adapted to receive the surge valve l5 previously mentioned. Similarly, the main cylinder 34 is provided with an aperture 36 for receiving the main surge valve |4, also previously mentioned; The main cylinder 34 is further provided with a port 31 leading, by way of the line 38, to the main cylinder release valve l1, from which the line: 39 leads through the choke valve 20 to the bypass valve I8 The line 46 also interconnects the main cylinder release valve l1 and the by-pass valve |8. The main cylinder release valve 1 1 discharges directly into the surge tank 4| of the press ||l by way of the line 42, containing the choke valve l9. The line 43 leads from the main cylinder release valve H to the return line 44 of the main pump The check valve I6 is installed at an intermediate point along the line 43 and within the Main pump and associated circuit v The main pump II is provided with a pressing line 45 opposite the return line 44, and receives pressure fluid from the pumpv while the main plunger 32 is performing a drawing operation.

The line 45 enters the main cylinder 34 through the port 4|i. The main pump I is provided with a servomotor cylinder 41 containing a servo-pi:-

ton (not shown) for shifting the shift ring of the pump I to vary or reverse the discharge thereof. The servomotor 41 is controlled manually by a servomotor valve 48, containing a valve plunger 49 operated by a hand lever 50. The servomotor valve 48 is connected to the surge .tank 4| by means of the pipe line 5|. The'servomotor 41 and servomotor valve 48 are interconnected by means of the pipe lines 52 and 53, respectively. The servomotor 41 is also automatically operated on the return stroke by a pilot piston within a pilot. cylinder 54, through the pilot line 55 running to the return line 44 of the main pump and on the pressing stroke by a differential pilot The clamping block 22 is' mounted shifting the manual control lever 50.

tails of the servomotor valve 48 and the servo-- below.

51, connected to the suction side of the pump l2.

The pressure side of the pump I2 is connected to the suction line 51 by means of the by-pass line 58, containing the pressure relief valve 59, and is also connected to the servomotor valve 48 by means of the pressure line 66. When the servomotor valve 48 is moved into such a position that the pressure line is blocked, the discharge of the. pump |2 passes through the pressure relief valve 59 to the suction line 51, and is accordingly by-passed until the line 66 is again opened by The demotor 41 form no part of the present invention,

and will be found fully disclosed in the Ernst Patent, No. 2,038,272, dated April 21, 1936'.

Combination relief and check valve The return line 44 from the main pump leads to the combination relief and check valve I I3, beyond which the line 6| leads to the port 62,

discharging into the return side ofthe main cylinder 34. The valve l3 consists of a casing 63 having a chamber 64 with a port 65 closed by a ball 66. Opposite the port 65 is aplug 61 containing a bore 68, in which reciprocates the valve plunger 69. A portion 16 of the chamber- 64 intersects the bore 66. The plunger 69 isprovided with an enlarged portion 1| engaged by a coil spring 12, the opposite end of which engages the collar 13, acted upon by the adjusting screw 14 mounted in the threaded bore 15 of the valve cap 16. The latter is'mounted upon the valve casing 63. The pipe line 44 opens into the chamber 64 by way of the port 11, whereas the pipe line 6| leads outwardly from the port 18 in the chamber'19 containing the ball 66..

Accordingly, fluid may pass freely from the main pump along the line 44, through the valve l3 and the line 6|, into the return side of the main cylinder 34 by merely displacing the ball 66 from its position closing the port 65.

' Fluid proceeding in the opposite direction, however, cannot pass freely, but forces the ball 66 against the port 65 to close this port. Pressure is built up in the chamber 19 containing the ball 66 until this pressure is sufiicient to force the plunger 69 upwardly against the urge of the coil spring 12, whereupon the entrapped fluid is re-' leased through the bore 68' into the extension 16 of the chamber 64, and thence escapes through the line 44. The detailed operation of the combination relief and check valve |3 is described Auxiliary or. clamping pump The auxiliary pump or clamping pump 2| serves to supply pressure fluid to the clampingv cylinders 28 for the operation of the clamping plungers 21 for moving the clamping slide 26, and is shown in detail in Figure 3. This pump consists of a casing 86 containing a shift ring 8| or reversed. The shift ring 8| is mounted upon the rods 82 and 83, secured within the diametrically opposite threaded bores 64.

The r 92 passes through the antileakage packing 95 and the retaining cap 96 therefor,

.and is threaded upon its outer end, as at 91, to

receive the nut 99 and the stop nut 99. Also threaded upon the threaded portion 91 is a sleeve 99, to which is secured the hand wheel 9|, as by the set screw 92 and key 93. The sleeve 99 en- 1 gages the ball thrust bearing 94, the opposite side of which engages a sleeve 95 arranged to compress a coil spring 99 when the hand wheel 9| and threaded sleeve 99 are rotated to move threaded upon the threaded portion 91, but isprovided with a bore I99, which is spaced apart from the threaded portion 81.

To the opposite side of the pump 2| is secured a tubular portion I9I, through which passes the rod 93, and which is closed by a cap I92 having an, end plate I93. The cap I92 contains a bore I94, within which reciprocates a piston head I95 which is mounted uponthe rod 93 and retained in position by the head-I96 thereof. The piston head I95 is provided with an annular shoulder I91 lying within the annular chamber I99, from which the line I99 leads, through the choke valve I I9 to the pressure side of the auxiliary pump 2 I. Also mounted upon the rod 93 is a piston head III, adapted to reciprocate within'the bore II2 H of the tubular member I9I.

(III

The line H9 leads from the bore II2 on the left-hand side. of the piston head III to the servomotor line 53, interconnecting the servomotor valve 49 with the servomotor 9?, of the main pump II. The line 53 supplies pressure fluid from the servomotor pump I2 to the servomotor 91 to reverse the main pump andcause it to deliver pressure fluid through the return line 99 to the return side of the main cylinder 39. When this is done it will be obvious that pressure fluid will also flow through the line .I I3 into the bore II2, and act upon the piston head III forcing it to the right (Figure 3), and causing it to engage the piston head I95 and force the rod 99 and shift ring M of the pump IN to the right, in a manner subsequently to be described in connection with the operation of the circuit as a whole.

. The auxiliary pump 2I is supplied with fluid from the surge tank 9I by way of the suction line H4, and discharges pressure fluid from its pressure side through the pressure line I I5 and the ports H9, into the clamping cylinders 29 above the clamping plungers 21. From the bore I99 the port H9 opens into the 1ine.I I9, which leads to the main surge valve It to render the latter operative or inoperative, in the manner described below.

. Main surge valve The main surge valve I I of the present invention (Figure 4) consists of a tubular casing I29 mounted in the bore 39 in the head of the main cylinder 39 and. containing an end cap I2I. The tubular casing I29 is provided with outlet ports I22 leading from the interior into the chamber formed by the main cylinder 39 above the main piston'head 33. The end cap I2I is provided with a projection I23, serving as a seat for the coil spring I24, the opposite end of which urges upwardly the surge valve member I25. The latter is provided with a beveled portion I29 adapted to engage a valve seat I21 in the casing I29, and is also providedwith fluted portions I 29 along its upper extent so as to permit fluid to pass through the passageway I29, by way of the fluted portions'I28, between the valve seat I21 and the beveled portioni29, through the ports I22 into the main cylinder, and vice versa, when the main surge valve I4 is open.

Mounted above the'tubular casing I29 is a cylindrical casing I39 having a flanged portion I3I resting upon the outer wall of the main cylinder 34, and provided with passageways I32 leading from the surge tank into the interior of the valve (Figure 4). The cylindrical casing I39 is provided with a bore I33, within which the valve-.

operating rod I34 is reciprocably mounted. The rod I34 is provided with a head I35,41rged in an I upward direction by the coil spring I36 contained within the counter-bore I31. The upper portion of the counterbore I31 is closed by a cap I39 having a bore I39 within which reciprocates. a piston rod I49, having an annular shoulder I4I formed by a'piston head I42.

The piston head I42 reciprocates within a bore I 43, access to. which is gained through the port I44 leading to the pipe line H9. Above the piston head I42 is an annular enlargement I45, urged downwardly by the coil spring I46 within the chamber I41. The opposite end of the coil spring I49 engages the end wall I98 containing the port. I49 opening into the pipe line I59. The latter leads to the pipe line 43, and is joined at an intermediate point by the pipe line I5I leading thereto from the surge valve I5. When the main pump II is set to discharge pressure fluid into the return side of the main cylinder 34, as will subsequently appear, pressure fluid likewise passes along the lines I59 and I5I to operate the surge valves I4 and I5.

Operation In the operation of the press andcircuit shown in Figure l, a work-piece 25, in the form of a metal blank, is placed upon the clamping block 22 immediately above the die 29. The main pump II and auxiliary pump 2! are then started in operation, and the hand lever 59 is set at such a position that pressure fluid is delivered from the servomotor pump I2, through the servomotor valve 99 and the line 52', into the servomotor cylinder 91 to operate'the servo-piston to shift the shift ring of the main pump II to a forward delivery position. The main pump II then draws fluid through the port 92 on the return side of the main cylinder 34 by way of the line 9I, the combination relief and check valve I3 and the line 99, and discharges it under pressure through the line 95 leading to the pressing side of the main cylinder 39 above the main piston head 92. Meanwhile, the auxiliary pump 2i withdraws fluid through the suction line H9, and discharges it through the pressure line H5, through the ports H5 into the space above the clamping plungers 2'I.

The weight of the clamping slide, the clamping plungers 21, the main platen 9i and the main plunger 32 causes these parts to descend under the influence of gravity, opening the surge valves I4 and I5 and permitting fluid to passdirectly from the surge tank 4| into the clamping cylinders 29 and main cylinder 34. In the main surge valve I4 this fluid passes through the passagecoil spring I24 (Figure 4). The interior arrangement of the surge valve I5 and its action in this respect are similar to the arrangement of the lower portion of the main surge valve shown in Figure 4. In this way the descent of the clamping plungers 2'! and main plunger 32 is brought about more rapidly than would be possible by the use of pressure fluid discharged from the main pump Ii and auxiliary pump 2| without the action of the surge valves I l and Ill.

At this point, however, it is necessary that the clamping slide 28 and main platen 3| descend in unison for if the main platen 3| gets ahead of the clamping slide 28 the punch III will start its drawing action before the work-piece 28 has been clamped between the clamping slide and the clamping block 22, This action is prevented by the operation of the combination relief and check valve I3.

To this end, the thrust of the spring I: (Figure 2) is adjusted so that the combined weight of the main plunger assembly and clamping plunger assembly, acting upon the fluid entrapped beneath the main piston head 38, will be Just sufficient to move the relief valve plunger 89 to open the valve. The clamping plunger assembly can never move ahead of the main plunger assembly because of the shoulders 29. The instant the main plunger assembly tends to move ahead of the clamping plunger assembly, however, the relief valve plunger 68 will close, because the weight of the main plunger assembly is insufiicient to keep it open-without the added weight of the clamping plunger assembly. For

' this reason also, the instant that the clamping plunger assembly engages the work-piece 2d and halts, the main plunger assembly will also halt until pressure is built up in flie main cylinder 3! sufficient to open the valveplunger 89' oi? the valve it. Obviously, the seating of the ball 88 will prevent fluid from passing from the chamber 19, through the port 88, into the chamber 88.

(Figure 2.) I

Meanwhile, the auxiliary pump II has been operating and discharging fluid into the clamping cylinders 28. As the clamping slide 28 comes to rest against the work-piece 28, pressure is built up by the pump 2i within the clamping cylinmove to the right, overcoming the contrary urge of the coil spring 86 on the opposite side of the pump 2|. The coil spring is so arranged as to urge the shift ring 8| of the pump II to the left, into its full forward delivery position. As

the piston head I88, acting against the head I I8 coil spring I48. This lifts the piston rod I48- and permits the operating rod I 38 to rise against the urge of its coil springl", thereby permitting the surge valve member I28, which has hitherto been forcibly held open by this means, to close by moving upwardly.

Any excess discharge of the main pump II into the main cylinder 34 above the piston head 33 which might have otherwise served to force the main plunger 32 to move ahead of the clamping plungers 27 has, in the meantime, been discharging through the main surge valve It by way of the ports M2, the fluted portions 82 and the passageways I32 into the surge tank di so that no excess pressure could build up within the main cylinder 86 until the clamping plungers had fully clamped the work-piece in position. The closing of the main surge valve it, however, by the action of the fluid passing along the line Ilt from the auxiliary pump 2i enables the main pump II to accumulate pressure within the main cylinder 36 only after a sumcient clamping pressure has been accumulated within the clampingcylinders as. In this manner it is impossible for the main plunger 32 to get ahead of the clamping plungers t? or to start a drawing operation before the clamping plungers 21 have fully engaged the work-piece 28.

' As previously stated, the main plunger 82 could not advance further by gravity because it lacks At this juncture the clamping slide 28 has come to rest, clamping the work-piece between it and the clamping block 22, and the main platen 3i and punch 36 have also come to rest. By reason of the closing of the main surge valve M,

, pressure now is built up within the main cylinder 81Lby the main pump Ii until the punch is forced downwardly against the work-piece 28,

performing the drawing operation and forcing it into the recess 24 in the die 23.

- When this operation is completed it is necessary to reverse the operation of the press and withdraw the clamping plungers and main plunger. In order to relieve the pressure in the clamping cylinders 28 before the main platen 8| picks up the clamping slide 26 by engaging the shoulders 28, the control devices associated with the auxiliary pump 2i come into play. When the hand lever 88 is shifted to throw the main pump II into a reverse delivery position, pressure fluid is discharged into the servomotor line 53 from the servomotor valve 48, and operates the servo-piston .within the servomotor cylinder 41 to accomplish this. A part of this pressure, however, passes along the line I I8, into the space to the left of the piston head III of the auxiliary 'pump 2|, moving the piston head II I to the right and causing it to shift the rod 83 and the shift ring 8| to the right. The shift ring 8| thereby moves through the neutral delivery'position of the auxiliary pump 2| into the reverse position thereof, thereby immediately relieving the pressure within the clamping cylinders 28 before the main platen 3| engages the shoulders 28 of the clamping slide 26. The pressure fluid from the main pump II is discharged through the return amazes line H, the combination relief and check valve l3 and the line 8|, into the space beneath the main piston head'33, raising the main plunger 32 and retracting the main platen 3| and theclamp ing slide 26 simultaneously by their interengagement at the shouldered portions 28 of the clamping slide 26. r

The instant the main pump I I is reversed to retract the main plunger .32, pressure fluid passes along the lines 44,- 43 and I and HI to the main and clamping cylinder surge valves I4 and 15, respectively. This fluid (Figure 4) acts against the upper end of the piston rod I40 within the chamber In, and iorcesit downwardly, opening the surge valve member I25 and' permitting the fluid to escape from the top of the main cylinder 34 directlyinto the surge tank 4|. At the same time the surge valve I! will be opened by the pressure fluid reaching it along the line I 5!, permitting the escape of the fluid from the clamping cylinders 28 into the surge tank 4|, as described in the previously mentioned Ernst Patent No. 1,892,568, of Deceri'iber 27, 1932.

It will beunderstood that I desire to comprehend within my invention such modifications as come within the scope of the claims and the invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is: g I

1. A surge valve comprising a casing having a lower chamber, a middle chamber and an upper chamber, said lower chamber having a valve seat and passageways extending, through saidcasing from opposite sides of said valve seat, a valve member reciprocable in said lower chamber, resilient means for urging said valve member into closing engagement with said valve seat, a valve operating element reciprocable in said middle chamber and engageable with said valve member, resilient means for urging said valve operating element out of engagement with said valve member, a double acting plunger reciprocable in said upper chamber and means for admitting preasure fluid to said upper chamber on opposite sides of said double acting plunger.

2. A surge valve comprising a casing having a lower chamber, a middle chamber and an upper chamber, said lower chamber having a valve seat and passageways extending through said casing from opposite sides of said valve seat, a valve member. reciprocable in said lower chamber, resilient means forurging said valve member into closing engagement with said valve seat, a valve operating element reciprocable in said middle chamber and engageable with said valve member, resilient means for urging said valve operating element out of engagement with said valve member, a double acting plunger .reciprocable in said upper chamber, means for admitting pressure fluid to said upper chamber on opposite sides-of said double acting plunger and resilient means realtively more powerful than the previously mentioned resilient means for urging said double acting plunger downward to shift said valve operating element to move said valve member away fromits seat.

3. A surge valve comprising a casing having a lower chamber, a middle chamber and-an upper member, a double actingplunger reciprocable in said upper chamber and means for admitting pressure fluid to said upper chamber on opposite sides 01 said double acting plunger, said valve membe said valve operating element and said 0 double acting plunger being reciprocable along a common axis of reciprocation.

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