US2294451A - Blank holder and die cushion cylinder having separate adjustable pressures - Google Patents

Blank holder and die cushion cylinder having separate adjustable pressures Download PDF

Info

Publication number
US2294451A
US2294451A US326709A US32670940A US2294451A US 2294451 A US2294451 A US 2294451A US 326709 A US326709 A US 326709A US 32670940 A US32670940 A US 32670940A US 2294451 A US2294451 A US 2294451A
Authority
US
United States
Prior art keywords
conduit
pressure
fluid
cylinder
cylinders
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US326709A
Inventor
Ernst Walter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HYDRAULIC DEV CORP Inc
HYDRAULIC DEVELOPMENT Corp Inc
Original Assignee
HYDRAULIC DEV CORP Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by HYDRAULIC DEV CORP Inc filed Critical HYDRAULIC DEV CORP Inc
Priority to US326709A priority Critical patent/US2294451A/en
Priority claimed from US36744740 external-priority patent/US2350884A/en
Application granted granted Critical
Publication of US2294451A publication Critical patent/US2294451A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21DWORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D24/00Special deep-drawing arrangements in, or in connection with, presses
    • B21D24/10Devices controlling or operating blank holders independently, or in conjunction with dies
    • B21D24/14Devices controlling or operating blank holders independently, or in conjunction with dies pneumatically or hydraulically

Description

Sept. 1, 1942 W. ERNST SEPARATE ADJUSTABLE PRESSURES Filed March 29, 1940 5 Shets-Sheet 1 m 4 4K I I I F-i l P 2? I I I2 0 L...
T l5 HI 2 n9 v in 57 9 f i m N i wzzavrop 7 vmumm/vsr o /Z z n' Sept. 1, 1942. w. ERNST 2,294,451
BLANKHOLDER AND DIE CUSHION CYLINDERS HAVING SEPARATE ADJUSTABLE PRESSURES Filed March 29, 1940' 5 Sheets-Sheet 2 FIE'nE Sept. 1, 1942. ERNST W. BLANKHOLDER AND DIE CUSHION CYLINDERS HAVING SEPARATE ADJUSTABLE PRESSURES Filed March 29, 1940 FIB-.3
5 Sheets-Sheet 3 v Sept. 1, 1942. w. ERNST 2,294,451
BLANKHOLDER AND DIE CUSHION CYLINDERS HAVING SEPARATE ADJUSTABLE PRESSURES Filed March 29, 1940 5 Sheets-Sheet 4 L 0 N a a Q 7 0 Q I Q Q s; I 1
m 2 r Y l l s i N Q U] r V x r Sept. 1, 1942. w. ERNST 2,294,451
v BLANKHOLDER AND DIE CUSHION CYLINDERS HAVING SEPARATE ADJUSTABLE PRESSURES Filed March 29, 1940 5 Sheets-Sheet 5 Q I Q Q N lA/VE/VTOP MATE/P EPA/67 5 we ATTOF/VEYF Patented Sept. 1, 1942 mm: nouma AND ma cusmoN cynnmsn mvmc SEPARATE anms'raam PBESSURES Walter Ernst, Mount Gilead, Ohio, assignor to The Hydraulic Development Corporation, 1110., Mount Gilead, Ohio, a corporation of Delaware Application March 29, 194', Serial N0. 326,709
7 Claims. (Cl. 113-45) This invention relates to presses, and in particular in hydraulic presses having blank holding arrangements in association with drawing de- .vices.
One object or this invention is to provide a hydraulic press having a drawing plunger and a plurality of clamping cylinders which will make it possible to exert and maintain different pressures in the clamping cylinders, and to vary the pressure in the individual clamping cylinders independently of each other.
It is another object or this invention to provide a hydraulic press having-a drawing plunger and a plurality of clamping cylinders, in which the pressure in each clamping cylinder is individually controllable and automatically maintained .by means associated with said clamping cylinders.
A further object orl the invention consists in providing a hydraulic press ofthe character' referred to in the preceding paragraph in which each clamping cylinder is associated with a variable delivery pump which automatically .varies its flow of fluid so as to maintain the desired pressure in the clamping cylinder pertaining thereto.
It is a still further object oi the invention to provide a hydraulic press having a drawing plunger, a plurality of clamping cylinders, and cushioning cylinders which will make it possible individually to .vary and maintain the pressure in each clamping and cushioning cylinder.
These and other objects and advantages will appear more clear from the following specification in connection with the accompanying drawings in which:
' Figure 1 diagrammatically illustrates a press according to the present invention at the beginnin'g of the downward stroke of the clamping plungers;
Figure 2 is a view similar to Figure 1, but showing the press at the end of the clamping stroke;
Figure 3 is a section along the line 3-3 of Figure 1;
Figure 4 is a section similar to Figure 3 with the exception that the pumps associated with the clamping cylinders are replaced by pressure reducing valves;
used in connection with the hydraulic circuit of Figure 'I. a
The press as illustrated in the drawings comprises a bed I and a head 2 spaced from and connected with each other by strain rods 3 and nuts 4. The head 2 carries a main cylinder 5 and clamping cylinders 6. The main cylin'der 5 has reciprocably mounted therein a plunger 1] carrying a press platen 3 which, in its turn, supports an upper die 8. The lower end of the main cylinder 5 is provided with packing material II compressed by a gland H for preventing leakage from the main cylinder. Similarly, each of the clamping cylinders i is provided with packing material I2 compressed by a gland 13 for preventing leakage from the respective clamping cylinder.
Through each gland I3 and packing material I2 of the clamping cylinders is passed a clamp ing rplunger l4 carrying a blank holder IS. The press platen 3 and blank holder 1 5 have lugs" and I1 respectively through which a rod l3 with nuts I! and 20 is passed so that the blank holder I! is lifted by the press platen when the latter has moved a predetermined distance away from the blank holder. The main cylinder 5 is connected at its upp'r end with a conduit 2| leading to one port 22 of a variable delivery pump 23, while the other port 24 or the pump 23 is connected with a conduit 25 leading to the lower end or the cylinder 5.
Each of theclamping cylinders 3 is connected by means of a conduit 26 with a conduit 21 leading to a two-way valve 23 and having mounted therein a check valve 23 which opens in the direction of the arrow A only. The two-way valve 23 comprises a cylinder 33 closed at its ends by packing material 3| and 32 and heads 33 and 34. The cylinder 33 has three aligned bores 35, 33 and 31 of a diameter corresponding to the diameter of pistons 33 and 33 connected'with a push rod 40. The bores 35 and 36 are separated from each other by a chamber 4! having a diameter greater than those 01' the pistons 33 and 33. Similarly the bores 36 and 31 are separated by a chamber 42 which has a diameter likewise greater than those of the pistons 33 and 33.
A conduit 43 leads from the chamber 42 to a fluid tank 44, while the conduit 21 leads into the chamber 4|. The fluid tank 44 has mounted therein a valve 45 for releasing the pressure in I the upper portion of the main cylinder 5 at th' beginning of the return stroke of the plunger 1. This valve 45 comprisesa casing 46 having two be spring chamber 41 and 43 and two cylinder bores 49 and 56. The cylinder bore 46 is adapted to communicate through an aperture with the fluid tank 44, and similarly an aperture 52 is provided for effecting communication between the cylinder bore 56 and the fluid tank 44. Furthermore, a channel 56 is provided for effecting a communication between the two bores 49 and 56. A conduit 54'leads from the bore 56 to the conduit 2|, while a conduit 55 leads from the cylinderbore 49 to the conduit 25. A conduit 56 branches off from the conduit 54 and leads to the cylinder bore 49. Reciprocably mounted in the cylinder bore 49 is a valve member 51 with two pistons 56 and 59 which, in the position shown in Figure 1, close oi! the channel 53 and the aperture 5I.
Connected with the piston 59 is an abutment 66 which is engaged by a spring 6i provided in the spring chamber 41 and urging the valve member 51 toward the right. Similarly, a spring 62 in the spring chamber 46 engages an abut-' ment 63 connected with a piston 64 reciprocable in the cylinder bore 56. The piston 64 forms a part of the valve member 65 which carries a second piston 66. In the position shown in Figure 1, the piston 64 closes the aperture 52, while the piston 66 prevents communication between the conduit 54 and the channel 53. A conduit 61 leads from the fluid tank 44 to the port 24 of the pump 29 and has mounted therein a check valve 66 which opens only in the direction of the arrow B.
A further conduit '69 leads from the fluid tank 44 to a chamber 16 of a surge valve generally partition 19 is provided with a bore through which is passed a piston rod 16 carrying a piston 11. A spring 16 is mounted between the parti-' tion 13 and the piston 11 urging the piston 11 upward. The partition 15 is likewise provided with a bore 19 which has a diameter greater than the diameter of the piston rod 16. The cylinder bore 14 has also reciprocably mounted therein a piston 66 urged by a spring 6| to its uppermost position. In this uppermost position the piston 66 closes ofl a port 62 connected with the conduit 2| by a conduit 63. A conduit 64 leads from the lower part of the cylinder bore 14 to the conduit 54,-while a conduit 65 leads from the upper portion of the cylinder bore 12 to the conduit 55.
The push rod 46 passing through the two-way valve 26 has adjustably mounted thereon two cams 66 and 61 having grooves 66 and 69 respectively. The cams 66 and 61 cooperate with pins 96 and 9| carried by an arm 92 connected with the press platen 6. The arm 92 has a bore 93 through which the cams 66 and 69 may pass. The pins 96 and 9| are urged toward the bore 99 by springs 94 and 95 provided in arm 92 so that the pins may engage the groove 66 or 69 as the case may be. The lower end of the push rod 46 is passed through a lug 96 connected with the bed I. The bed I carries cushioning cylinders 91 having reciprocably mounted therein cushioning plungers 96 passing through packing material 99 compressed by a gland I66 and carrying the lower die I6I.
According to the embodiment of Fig. 3, each of the clamping cylinders 6 is connected with the pressure side of a variable delivery pump I62 by means of the conduit 26. The suction side of each delivery pump I62 is connected by means of a conduit I66 with a fluid tank I64 which, if desired, may be connected with or form a part of the fluid tank 44. Branching oi! from the conduit 26 is the conduit 21 leading to a channel I66 of the check valve 29 (see also Fig. 1). The channel I66 is normally closed by a ball I66 arranged in a chamber I69 of the check valve 29. The chamber I69 communicates through a channel II6 with the chamber H of the two-way valve 26. As will be clear from the foregoing, the four check valves 29 prevent the pressure from equalizing in the four clamping cylinders 6, whereas the two-way valve 26 is adapted to open the clamping cylinders to exhaust.
The variable delivery pump I62, shown in detail in Figure 5, comprises a pump casing III having connected to one side thereof, for instance by means of screws 2, a hollow arm H3. Telescoped in the hollow arm H9 is a spring casing II4 engaged by one end of the spring II5. The other end of the spring II5 abuts the wall-H6 of the hollow arm II6. Reciprocably mounted within the pump casing III is a flow-control member I I1 adapted to vary the flow of the variable delivery pump by moving a secondary rotor relatively to a primary rotor. Moreover, a pluralit of radial pistons and cylinders (not shown) are operatively connected with said rotors. The arrangement of these rotors and the interior of the pump is well-known to those skilled in the art and for more detailed description thereof, reference may be had to U. S. Patents Nos. 1,964,244 and 2,041,172.
Threaded into or otherwise connected with the flow-control member H1 is an adjusting rod 6 which passes through the pump casing III and the wall II6 of the hollow arm H3 and is provided with a threaded portion I I9 passing through the spring casing H4. The threaded portion H9 is engaged by a nut I26 provided with a handwheel I2I so that by rotation of the handwheel I 2| in one direction; the spring casing |l4,may be moved into the hollow arm II3 thereby increasing the thrust of the spring, whereas the rotation of the handwheel I2I in the opposite direction allows the spring II5 to expand. Screwed to or otherwise connected with the opposite'side of the'pump casing is a cylinder I22 having a cylinder bore I26, closed at its outer end by a gasket I24 and a cylinder head I25. Reciprocably mounted in the cylinder bore I26 is a piston I26 connected with a push rod I21 threaded into the flow-control member 1. Adjacent the cylinder bore I23 and adapted to communicate therewith is a bore I26 having a diameter greater than the diameter of the cylinder bore I 23 and communicating through a conduit I 29 with the pressure side of the pump I62. Leakage from the bore I26 toward the interior of the pump casing III is prevented by packing material I66 provided between the pump casing III and the cylinder I 22 and surrounding the push rod I21.
As will be clear from the foregoing, the spring II5 tends to hold the flow-control member in a position determined by the setting of the spring, thereby maintaining a predetermined flow of fluid of the pump I62. However, if the fluid pressure of the pump exceeds a predetermined value, this pressure will be conveyed from the pressure side of the pump through the conduit I29 into the bore I26 where it acts upon the piston I 26 and moves the latter somewhat toward the right until equilibrium is established between the pressure acting upon the piston I26 and the valves I3I I thrust of the spring acting in the opposite direction. The movement of the piston I26 toward the right causes the flow-control'member to restrict the flow of fluid of the pump I02. In this way, the pump I02 automatically maintains the desired fluid pressure.
According to the embodiment of Figure 4, the pumps I02 are replaced by pressure reducing which are supplied with fluid from a common variable delivery pump I42. Since this pump as shown in the drawing lacks the servomotor conduit I29 of the pump I02, provision is made for preventing excessive pressure in the conduits between the pump I42 and the pressure reducing valves I3I. To this end aconduit I43a comprising a relief valve I42a connects the pump I42 with the tank I44. The relief valve 2:; is so set that its opens towards the tank I44 at a pressure slightly higher than the denied pressure in the clamping cylinders. Aside from the above mentioned features the arrangement shown in- Figure 4 corresponds to that of Figure 3 and the corresponding parts are designated with the same reference numerals, however with the additional letter a.
The pressure reducing valve I3I comprises a body member I 32 (see Figure 6) having reciprocably mounted therein a plunger-I33 guided by a guide ring ably of U-shaped leather mounted between rings I36 and I31. A shoulder I38 on the body forms a seat for the ring I36, and a screw plug I39 threaded into the body I32 presses the ring I31 against the packing I35.
The body I32 of each of the four pressure reducing valves shown in Fig. 4 is provided with an inlet I40 connected with a conduit I03a leading to a manifold I4I which is connected with the pressure side of the variable delivery pump H2. The suction side of the variable delivery pump I42 communicates through a conduit I43 with a fluid tank I44 which may be connected with or fonn a part of the fluid tank 44. The inlet I40 (see Fig. 6) communicates openings I46 in the ring I31 with a central chamber I41 in theend of the plunger I33. A plu- I34 and by a packing I35 preferthe sleeve I55 connected with the casing I54. The upper end of the spring I50 rests against the v nut I59 while the lower end of the spring abuts the washer I49. The stem I58 is provided with a handwheel I62 by which it may be rotated, and since the nut I59 cannot rotate with the stem I51 due to the engagement of its pins I6I with the slot I56, the rotation of the handwheel will cause the nut I59 to move longitudinally of the casing so as to vary the thrust of the spring I50.
A. passage I63 affords communication between the chamber I5I and the interior of the casing I54 when the plunger I33 is moved inwardly sufliciently to lift the washer I49 off its seat onthe body'and thus open the communication, it being understood that the interior of thecasing I54 is always under more or less' pressureby reason of the fluid entering between the washer I49 and the sleeve I55 and around the plunger I33.
The valve opens in thefollowing manner: The hydraulic pressure entering through the inlet I 40 and the passage I45 is supplied to the plunger I33 within the chamber I41 and also at the end of the plunger I33. This pressure being greater than that of the spring I50 moves the plunger inward. As soon as the ports I48 pass beyond the packing I35 and open communication with the chamber I5I, .thefluid will pass therethrough and through the passage I63 into the spring chamber, thus affording a back pressure upon the plunger I33 in addition tothe pressure of the spring I50. The pressure on the two sides. of the plunger I33 will therefore tend to arrive at a balance, and it is evident that the pressure at the low pressure outlet I52 will be r equal to the high pressure minus the pressure 'acting from the interior of the shell I55 upon by an inclined passage I and rality of small ports I40 radiate from the chamber I41 and pass through the plunger. The inner end of the plunger I33 is provided with a shoulder which rests against a washer I49 which is forced outwardly by a spring I50 and therefore tends to resist the inward movement of the plunger. A chamber I5I within the body I32 communicates by means of an outlet I 52 with a conduit 26a leading to the respective clamping cylinder 6a and the check valve 29a. Since the clamping cylinder 6a and check valves 29a fully correspond to the clamping cylinders 6 and check valves 29 respectively, no further explanation is necessary. The ports I48 are adapted to communicate with the chamber I5I when the plunger is forcedinwardly by a predetermined amount.
Screw threaded into the body I is a casing I54 which is welded or otherwise fastened to a sleeve I55 which is preferably of non-corrosive metal.
' plunger their ends projecting into.the slots I56 and thereby prevent relative rotation between the nut and the washer I49. When the pressure at the outlet I52 increases, this .pressurewill be conveyed through the passage I63 to theinterior of the sleeve I55 and act therefrom upon the washer I49 so as to move the plunger I33. downwardly,
thereby restricting the flow of fluid through'the ports I48 into the chamber I5I. In this way the desired pressure at the outlet I52 will be automatically maintained.
Referring now to Figure 7 illustrating the hydraulic circuit for the cushioning cylinders 91, it willbe noted that each cushioning cylinder communicates through a conduit I64 with a check valve I65. This check valve I65 corresponds to the check valve I06 of Figure 3 and comprises a chamber I66 communicating through a channel I61 and a conduit I68 with the conduit I64. A further conduit I69 which may be closed by a ball I10 communicates with a conduit I'1I leading into a conduit I12 which, in its turn, is connected with the pressure side of a variable delivery pump I13. The suction side of the variable delivery pump I13 is connected with a fluid tank not shown in Figure 7. The conduit I64 is also connected with a relief valve I14 shown indetail in Figure 8.
The relief valve I14 consists of a casing H5 having a bore I16 wherein reciprocates a valve I11. Arranged between the valve plunger I11 and the bore I16 is a tubular member I18 having a longitudinal bore I19 and cross bore I80, the cross bore I communicating'with an annular chamber opening into a transverse bore I8I in the casing I15. The end iconnection I82 of the conduit I64 is held in communication with the bore I16 by means of a collar I83 engaging the threaded portion I84 of the casing I15, whereas a pipe connection I85 similar. to the pipe contransverse bore III by means of the threaded" ,collar I88 engaging the threaded portion I81 of the casing I15.
Mounted on the upper portion of. the casing I15 is a tubular cap I 88 secured thereto by screws I89. Within the cap I88 is a coiled spring I90, one end of which engages an enlargement I9I upon the upper end or the valve plunger I11, whereas the opposite end engages a button I92 in contact with an adjusting screw I93 threaded through a bore I94 in the upper end of the cap I88. Surrounding and covering the adjusting screw I98 is a hollow nut I95 which serves to protect the adjusting screw I93 and also to lock it in its adjusted position.
As will be clear from the foregoing description, the spring I90 will normally hold the plunger I11 in such a position that the latter prevents communication between the bore I19 and the transverse bore I8I. However, whenthe pressure inthe bore I19 exceeds a predetermined value determined by the setting of the spring I90, the plunger I11 will be lifted to such an extent that pressure fluid from the respective cushioning cylinder 91 may pass through the conduit I04 and the bore I19 into the transverse bore I8| and from there to the fluid tank. The fluid expelled from the respective cylinder 91 cannot escape to the conduit 1| since the communication between the conduit I58 and the conduit I" is closed bythe ball I10.
The operation of the device is as follows:
If a drawing operation is to be effected, the
workpiece I 96 is placed on the bed I and the hydraulic pump 23 is started and its control set so that fluid pressure passes through the conduit 2|. The plunger 1 first moves downwardly by gravity and the space above the plunger is filled by fluid from the pump 23 and from the tank 44 through the conduit 69 the surge valve 1| and the conduits 82 and 2|. It will be understood that the suction eifect in the conduit 2| and the conduits 54 and 84 causes the piston 80 of the surge valve to move downwardly so as to eflect communication between the surge'valve chamber 14 and the conduit 82 connected therewith. At the same time the clamping plungers I4 move downwardly by gravity and fluid from the variaable delivery pumps I02 (Figure 3) or the variable delivery pump I42 (Figure 4) flows through the into the clamping cylinders. The cushioning cylinders 91 are assumed to have been filled with fluid during the previous retraction stroke, so
. 1 the liquid in the lower portion of the main cylinder 5 escapes through the conduit 25 to the 09. Just before the upper die 9 contacts the workpiece I98, the pins 90, 9| of the arm 92 engage the groove 88 of the cam 86 and move the rod downwardly so as to shift the pistons 38 and 39 of the two-way valve 28 for interrupting the communication between the conduits 21 and 43. It will be understood that the rod 40 was previously held in its upper position by friction between the rod 40 and the packing material 3|, 32 surrounding the same. When the pistons 88 and 39 have reached their lower-most position while the downward movement of the die 9 still continues, the pins 90 and 9| click out of the groove 83, slideover cam 81 and at the end of the pressing or drawing operation are below the cam 81. When the drawing operation proper starts, the die 9 presses the workpiece I96 into the lower die against the resistance of the liquid in the cushioning cylinders 91. Fluid from the cushioning cylinders 91 can escape only through the relief valves I14 and the pressure in each cylinder 91 can be controlled by the adjustment of its respective relief valve, 1. e. by setting the screw I93 of the valve I14.
After the upper die 9 has moved the desired distance and completed its drawing operation the flow through the pump 23 is reversed by any desired means so as to initiate the retraction stroke of the plungerpl, When the pins 90, 9| during this retraction stroke engage the groove 89 of the cam 81, they move the control rod 40 and the pistons 38, 39 in the two-way valve 28 to their uppermost position indicated in Figure 1, thereby establishing communication between the conduits 21 and 43 so that liquid from the clamping cylinder G -may escape through the conduits .21, the check valves 29. the two-way valve 28, and the conduit 43 into the fluid tank 44. When the retraction stroke oi! the plunger 1 is about to be conduit 25 or conduits H311 and 260 respectively suction side 24 of the pump 23. As soon as the upper die 9 contacts the workpiece I98, pressure starts to build up in the main cylinder 5 above the plunger 1 and acts through the conduits 2| and 54 upon the piston 59 of the valve member 85 thereby moving the valve member against the thrust of the spring 52 toward the left so as to eflect communication between the conduit 54 and the channel 53. Furthermore, the pressure in conduct supported by the spring 18 moves the piston 11 upward while the spring 8| of the surge valve 1I' moves the piston 80 engaged thereby likewise upward so as to close commupreviously the piston. 66 was movedtoward the left, fluid from the upper portion of the main cylinder 5 may now escape through the conduits 2|, 54 and 56 into the cylinder bore 49 from where it flows through the apertures 52 into the tank 44. Furthermore, liquid may escape from the conduits 2|, 54 and 56 into the cylinder bore 49 and from there through the channel 53 and the aperture 52 into the tank 44.
The relief of pressure from the upper portion of the main cylinder 5 through the valve 45 enables the pressure in the conduit 55- to move the piston 11 of the surge valve 1| downwardly so as to push the piston 80 against the thrust of the spring 8|, thereby efiecting communication between the conduit 2| and the conduit 69 so that the liquid from the upper portion of the main cylinder 5 may now escape through the last-mentioned conduits into the surge tank. The pressure fluid delivered by the pump 23 through the conduit 25 into the lower portion of the main cylinder 5 now moves the plunger 1 upwardly. A portion of the pressure fluid also flows from the port 24 through the conduit 25a into the cushioning cylinders 91 so as to flll'the latter and to nication between the conduit 03 and the conduit ra se t e cushioning p ers to the po they occupy at the beginning of the drawing operation.
As previously mentioned, when the fluid pres-- sure in the clamping cylinders 6 exceeds a predetermined pressure, the delivery of the pump I02 is automatically restricted so'that the desired pressure is substantially maintained. If for some reason during the drawing operation the pressure in the clamping cylinders should still exceed a predetermined value, the respective check valves 29a come into operation so as to release the pressure until it again reaches the allowable value. As will be clear from the foregoing description, each clamping cylinder is individually controlled and may be individually adjusted according to the desired pressure in the repsective clamping cylinder. A similar automatic control of the clamping cylinders is eifected when the pumps I92 in the circuit of Figure 3 are replaced by the reducing valves |3l shown in Figure 4. In the latter case only one pump, viz. pump I42,
supplies fluid to the clamping cylinders, and the pressure reducing valves l3| automatically maintain the desired individual pressures in the clamping cylinders 6a according to the setting of the respective springs I50 in the pressure reducing valves I3I, as previously explained. The relief valves I88 associated with the cushioning cylinders prevent undue pressure in the cushioning cylinders, which pressure may be determined for each cushioning cylinder individually by the setting of the respective springs I90.
It will be understood that I desire to comprehend within my invention such modifications as come within the scope of the claims and the invention. For instance, it desired, the check valves 29 and 29a may be replaced by check valves in which the closure member is normally held in closed position by a spring. Also a constant delivery pump may be substituted for the variable delivery pump I42 or, preferably, the pump 2 with the conduit 3a and check valve 211 may be replaced by the self controlling variable de livery pump 12.
Having thus fully described my invention what I claim as new and desire to secure by Letters Patent is:
1. A hydraulic press comprising in combination a drawing plunger, a plurality of fluid operable clamping pistons reciprocable in clamping cylinders, a plurality of variable delivery pumps respectively associated with said clamping cylinders for supplying fluid thereto, said pumps being adapted automatically to vary the supply of fluid to said cylinders in response to the pressure prevailing in said cylinders, means adapted to prevent equalization of the pressure in said clamping cylinders, and valve means adapted to allow escape of fluid from said clampin cylinders during the retraction stroke of the drawing plunger, and means extending from said drawing plunger,
said extending means being located out of conand adapted automatically to vary the flow of fluid to said cylinder-piston-assemblies for maintaining' a predetermined pressure therein, the
pressure of each clamping cylinder-piston-assembly being variable independently of one-another, a plurality of cushioning cylinders with cushioning plungersreciprocable therein, a plurality of individually controllable pumps for supplying fluid to said cushioning cylinders and means associated with said pumps and adapted individually to vary and maintain the fluid pressure in said cushioning cylinders. I
3. A hydraulib press comprising in combination a drawing plunger, a plurality of fluid operable clamping members for holding a workpiece during the drawing operation of said drawing plunger, a plurality of pumping means operable independently of each other individually supplying pressure fluid to said clamping members, means associated with said clamping members and adapted automatically to vary the supply of fluid to the respective clamping member and to maintain a predetermined different pressure thereon, a pinrality of cushioning members cooperating with said drawing plunger during the drawing operation, further pumping means for supplying fluid to said cushioning members, and a plurality of relief valves associated with said cushioning members operable at the attainment of a predetermined pressure on said clamping members.
4. A hydraulic press comprising in combination a main cylinder, a drawing plunger reciprocable in said main cylinder and supporting an actuating member, a plurality of fluid operable clamping plungers reciprocable in clamping cylinders and adapted to hold a workpiece during rality of independently operable fluid supply means respectively associated with said clamping cylinders, means operatively connected with said fluid supply means and adapted automatically to control the supply of pressure fluid from said fluid supply means to saidclamping cylinders to create and maintain different predetermined pressures in different clamping cylinders, and valve means comprising a reciprocable valve and actuating means therefor located adjacent to said actuating member, said actuating means operable by said actuating member to release all fluid pressure in said clamping cylinders -in response to a predetermined point of travel of said drawing plunger during the retraction stroke thereof.
5. A hydraulic press comprising in combination a drawing plunger, a plurality of fluid operable clamping pistons reciprocable in clamping cylinders, a plurality of variable delivery pumps respectively associated with said clamping cylinders for supplying fluid thereto, said pumps being adapted automatically to vary the supply of fluid to said cylinders in response to the pressure prevailing in said cylinders, adjusting means associated with said pump for maintaining diflferent predetermined pressures in different clamping cylinders, a plurality of cushioning members cowith said cushioning members and having means adapted to maintain different pressures on difierent cushioning members, and means adapted to release the pressure in said clamping cylinders in response to a predetermined point of travel of I said drawing plunger during the retraction stroke pendent pumps connected into said closed'hyl5 draulic system eachsupplying fluid to each 01' the blankholder rams.
whereby they are hydraulically actuated in one direction onl a common valve controlling mechanism therefor actuated by the movement of a platenattached to the main ram, means interconnecting said main ram and blankholder rams whereby said main ram moves said blankholder rams in the opposite direction, and a plurality of independent pumps connected into said closed hydraulic system each supplying fluid to each of the blankholder rams, and means of adjusting the fluid pressure from each of said blankholder ram pumps.
WALTER ERNST.
US326709A 1940-03-29 1940-03-29 Blank holder and die cushion cylinder having separate adjustable pressures Expired - Lifetime US2294451A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US326709A US2294451A (en) 1940-03-29 1940-03-29 Blank holder and die cushion cylinder having separate adjustable pressures

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US326709A US2294451A (en) 1940-03-29 1940-03-29 Blank holder and die cushion cylinder having separate adjustable pressures
US36744740 US2350884A (en) 1940-03-29 1940-11-27 Blank holder and die cushion cylinder having separate adjustable pressures

Publications (1)

Publication Number Publication Date
US2294451A true US2294451A (en) 1942-09-01

Family

ID=23273332

Family Applications (1)

Application Number Title Priority Date Filing Date
US326709A Expired - Lifetime US2294451A (en) 1940-03-29 1940-03-29 Blank holder and die cushion cylinder having separate adjustable pressures

Country Status (1)

Country Link
US (1) US2294451A (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2417794A (en) * 1942-11-30 1947-03-18 Verson Allsteel Press Co Punch press having a die cushion
US2459888A (en) * 1944-12-06 1949-01-25 Hpm Dev Corp Momentary slowdown device for high-speed blank holder presses
US2460612A (en) * 1943-04-26 1949-02-01 Verson Allsteel Press Co Press with hydraulically controlled blank holder
US3147722A (en) * 1961-05-19 1964-09-08 Dro Engineering Company Di Die pads for ram type presses
US4056965A (en) * 1975-11-05 1977-11-08 Heiser Elmer F Press system or the like
US4185488A (en) * 1976-07-22 1980-01-29 Kraft, Inc. Method for forming a container pan
DE3019580A1 (en) * 1979-05-22 1981-01-22 Zaporozh Pk I T I HYDRAULIC PRESS
US4309888A (en) * 1976-07-22 1982-01-12 Kraftco Corporation Apparatus for forming a container pan
US4669298A (en) * 1982-08-30 1987-06-02 Amada Company, Limited Press
EP0475923A1 (en) * 1990-08-30 1992-03-18 Recherche et Développement GROUPE COCKERILL SAMBRE Device for regulating the force of the blank holder in a press
US6032504A (en) * 1997-10-16 2000-03-07 Cosma International Inc. Draw stamping die for stamping body panels for motor vehicles
US20100186475A1 (en) * 2009-01-26 2010-07-29 Honda Motor Co., Ltd. Press-die and press-working method

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2417794A (en) * 1942-11-30 1947-03-18 Verson Allsteel Press Co Punch press having a die cushion
US2460612A (en) * 1943-04-26 1949-02-01 Verson Allsteel Press Co Press with hydraulically controlled blank holder
US2459888A (en) * 1944-12-06 1949-01-25 Hpm Dev Corp Momentary slowdown device for high-speed blank holder presses
US3147722A (en) * 1961-05-19 1964-09-08 Dro Engineering Company Di Die pads for ram type presses
US4056965A (en) * 1975-11-05 1977-11-08 Heiser Elmer F Press system or the like
US4185488A (en) * 1976-07-22 1980-01-29 Kraft, Inc. Method for forming a container pan
US4309888A (en) * 1976-07-22 1982-01-12 Kraftco Corporation Apparatus for forming a container pan
DE3019580A1 (en) * 1979-05-22 1981-01-22 Zaporozh Pk I T I HYDRAULIC PRESS
US4669298A (en) * 1982-08-30 1987-06-02 Amada Company, Limited Press
EP0475923A1 (en) * 1990-08-30 1992-03-18 Recherche et Développement GROUPE COCKERILL SAMBRE Device for regulating the force of the blank holder in a press
US6032504A (en) * 1997-10-16 2000-03-07 Cosma International Inc. Draw stamping die for stamping body panels for motor vehicles
US20100186475A1 (en) * 2009-01-26 2010-07-29 Honda Motor Co., Ltd. Press-die and press-working method
US8250896B2 (en) * 2009-01-26 2012-08-28 Honda Motor Co., Ltd. Press-die and press-working method

Similar Documents

Publication Publication Date Title
US3543682A (en) Printing machines
US3962895A (en) Fluid forming apparatus having controllably variable forming pressure
US2352390A (en) Hydraulic jack
US3176590A (en) Clamping device
US3085530A (en) Hydraulic press ram cushion
US2157240A (en) Valve structure
US2192778A (en) Drawing press
US3096888A (en) Distributor device
US2407855A (en) Hydraulic press system
US2397270A (en) Hydraulic remote-control system
US2337573A (en) Fluid device
US2484603A (en) Hydraulic control device
US2448532A (en) Automatic power position hold for control valves
US2107190A (en) Plastic extrusion molding press
FR1453681A (en) Hydraulic lift assembly
US2565639A (en) Platen leveling multiple ram press
US2343167A (en) Press leveling means
US2309944A (en) Platen leveling device
US2218818A (en) Hydraulic die spotting press
US2318819A (en) Multiple action punch press die and cushion
US2335809A (en) Fluid operated motor
US2296051A (en) Balancing column for horn presses
GB1175707A (en) Stock Advancing Device for Punch Presses and the like
US2474772A (en) Unloading valve
US1970134A (en) Hydraulic press