US3268220A - Hydraulic cushion for dies - Google Patents

Hydraulic cushion for dies Download PDF

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Publication number
US3268220A
US3268220A US335730A US33573064A US3268220A US 3268220 A US3268220 A US 3268220A US 335730 A US335730 A US 335730A US 33573064 A US33573064 A US 33573064A US 3268220 A US3268220 A US 3268220A
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US
United States
Prior art keywords
valve
cylinder
pressure
tank
hydraulic fluid
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
US335730A
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English (en)
Inventor
Floyd M Williamson
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.)
DI-DRO ENGINEERING Co
DRO ENGINEERING Co DI
Original Assignee
DRO ENGINEERING Co DI
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 DRO ENGINEERING Co DI filed Critical DRO ENGINEERING Co DI
Priority to US335730A priority Critical patent/US3268220A/en
Priority to GB49883/64A priority patent/GB1074240A/en
Priority to DE19641502334 priority patent/DE1502334A1/de
Application granted granted Critical
Publication of US3268220A publication Critical patent/US3268220A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
    • B21D24/02—Die-cushions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B1/00—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen
    • B30B1/26—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen by cams, eccentrics, or cranks
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7758—Pilot or servo controlled
    • Y10T137/7762—Fluid pressure type
    • Y10T137/7764—Choked or throttled pressure type
    • Y10T137/7766—Choked passage through main valve head

Definitions

  • a principal object of the invention is to provide a hydraulic cushion in which the movable components of the pressure relief valve are free to react so as to minimize, it not entirely eliminate, the above-referred to difliculties.
  • Another object of the invention is to provide a new and improved hydraulic cushion which is more efficient and dependable in operation and better adapted for use at higher press speeds and where greater valve capacity is required.
  • FIG. 1 is a somewhat schematic illustration of a hydraulic cushion embodying my invention, with certain parts of the system shown in section;
  • FIGS. 2 and 3 are fragmentary views illustrating modified forms of the invention
  • FIG. 4 is a diagrammatic view of a crank type press relating ram speed and stroke with crank rotation and hydraulic fluid displacement from a hydraulic cylinder, the piston of which is connected to the crank by a pitman;
  • FIG. 5 is a diagram relating crank rotation to die pad travel
  • FIG. 6 is a diagram correlating hydraulic fluid displacement and velocity with crank movement.
  • a hydraulic cushion embodying my invention is adapted for use in a crank type press indicated generally at 10 having a crank 12, a pitman 14, a reciprocating ram 16, a die 18 movable with the ram 16, a bolster 2G, a fixed die 22 carried by the bolster, and a movable die or die pad 24 associated with die 22.
  • the hydraulic cushion includes hydraulic ylinders 26 mounted on the bolster, each having a piston or plunger 28 movable therein arranged to react on the die 24 so as to bias it to its extended position as illustrate-d.
  • the cylinders 26 are supplied with hydraulic fluid under relatively low regulated tank pressure (say, for examice ple, 100 lbs. per square inch) through a hydraulic fluid connection indicated generally at which includes conduit 30, certain passages in a valve indicated gene-rally at 32 to which the conduit 38 is connected, and a conduit 34 which is connected at one end to the valve 32 and at its other end to the lower end of a pressure tank 36 in which hydraulic fluid is maintained under a regulated pressure.
  • the hydraulic fluid connection 40 through which hydraulic fluid under tank pressure is supplied to the cylinders 26 includes bores 42 and 43, cross bore 44, bore 46, and cross bore 48 which interconnects the upper end of bore 46 and the conduit 34 leading to the tank 36.
  • the bore 46 includes valve chamber 50 and an annular valve seat 52 for a ball check valve 54 which is biased to closed position on seat 52, the check valve 52, 54 permitting hydraulic fluid flow from the bore 48 through the bore 46 into the bore 44, but not in the reverse direction.
  • the check valve 54 is seated by a relatively light spring 56.
  • the valve 32 as illustrated is made up of two valve blocks 55 and 57 suitably fixed together.
  • the block 57 is machine-d to provide two cylindrical valve chambers 60 and 62 which are intersected by the cross bore 48.
  • One end of the chamber 60 communicates with the upper end of the bore 43, while one end of the valve chamber 62 communicates with the upper end of the bore 42.
  • Each of the valve chambers 60 and 62 has a piston type, normally closed unloading valve therein, the valve in the chamber 60 comprising valve sleeve 64, valve piston 66, and valve spring 68.
  • the valve sleeve 64 is recessed on its outer periphery so as to provide communication between the parts of the bore 48 on opposite sides of the chamber 60.
  • the light spring 68 biases the piston valve member 66 against an annular shoulder 7 0, and the head of piston 66 is provided with a restricted orifice 72 which provides communication between the bore 43 and the space on the other side of the piston 66.
  • Valve seat 74 is disposed in the chamber 60 above the sleeve 64 and is provided with a central bore 76, a peripheral groove 78, and a series "of radial bores which interconnect the central bore 76 and the peripheral groove 78.
  • a cross bore 82 extends between the upper end of the valve chamber 60 and a bore 84 which also communicates through bore 85 with the upper end of the valve chamber 62.
  • bore 84 forms an expansible chamber in which a spring pressed piston 86 is disposed, a light spring 88 reacting on the piston 86 biasing the latter to its extended position at the bottom of the bore 84.
  • the back side of the piston 86 is exposed to atmosphere through one or more ducts 9i), and a set screw 92 provides an adjustable stop to determine the retracted position of the piston 86 and hence the maximum size of the expansible chamber provided by the bore 84.
  • the chamber 84 is in open albeit restricted communication with the work cylinders 26.
  • the spring 88 biases the piston 86 to its extended position as shown so that the volume of the expansible chamber is normally at its minimum.
  • the valve seat 74 at the upper end of the bore 76 provides an annular seat for a normally closed pilot valve member 168 biased to its seat on the valve seat 74 by a spring 182 which is adjustable whereby the relief pressure of the valve may be adjusted.
  • the pilot valve 74, 100 forms a part of a pressure relief valve means, the construction of which preferably is as disclosed in my Patent No. 2,901,238.
  • the valve member 100 is reciprocable in a bore 104 which communicates by bores 106 and 108 with one end of the bore 48 so that the hydraulic fluid which is passed by the pilot valve 100, 74 when the latter opens is free to flow through the bore 48 back toward the tank 36.
  • the spring 102 is adjustable so that the pilot valve 100, 74 will provide a predetermined resistance to displacement of hydraulic fluid from the cylinders 26 during the closing of the press ram so as to provide a hydraulic cushion of the desired resistance for the die 24. This resistance is substantially greater than the resistance afforded by the pressure in the tank 36.
  • the unloading valve 64, 66 which forms a part of the pressure relief valve means opens in response to a predetermined pressure diflerential across the piston 66 immediately following opening of the pilot valve 100, 74 and serves to by-pass hydraulic fluid from the high pressure or press side of the system to the low pressure or tank side so long as the pilot valve 100, 74 remains open.
  • the annular sleeve 64 is provided with a series of radially extending ports 110 which are exposed after the piston valve member 66 moves upwardly a predetermined amount in response to the pressure differential thereacross, whereby high pressure hydraulic fluid on the high pressure side of the valve 66, 64 is free to pass through the ports 110 and the chamber 60 into the bore 48 Without having to pass through the pilot valve 100, 74.
  • the unloading valve 64, 66 is effective to quickly pass substantial quantities of hydraulic pressure liquid from the high pressure to the low pressure side of the system during the closing of the press ram under the pressure regulation provided by the pilot valve 100, 74.
  • the unloading valve 64, 66 Will close as soon as the valve member 100 seats on its seat 74.
  • Valve chamber 62 is provided with a similar unloading valve comprising piston valve member 120, valve sleeve 122, and valve spring 124, and which functions like unloading valve 64, 66.
  • a similar unloading valve comprising piston valve member 120, valve sleeve 122, and valve spring 124, and which functions like unloading valve 64, 66.
  • One or more of such unloading valves may be used, depending upon the amount of fluid to be displaced during the closing of the press ram and the time avaliable for such displacement.
  • By using multiple unloading valves of the type illustrated it is possible to make the movable components of the pressure relief valve small and light as compared with the size and weight required for a single pressure relief valve.
  • means are provided to reduce the resistance toopening movement of the movable components of the pressure relief valve prior to the opening thereof so as to reduce, if not substantially eliminate, the generation of undesirable back pressure on the high pressure side of the pressure relief valve 32.
  • This makes the cushion more eflicient and dependable in operation at higher press speeds and where greater valve capacity is required.
  • the expansible chamber 84 has a volume approximating that of the hydraulic fluid displaced by the piston valve members 66 .and 120 in their movement prior to opening thereof, i.e., prior to uncovering of the ports 110.
  • valve members 66 and 120 are free to begin their opening movement under a pressure differential suflicient to overcome the light springs 68, 124 prior to opening movement of pilot valve 100, 74. This shifts valve members 66 and 120 to open position as soon as the bleed off pressure of pilot valve 100 is attained and without the generation of back pressures substantially in excess of the pressure of the valve 74, 100.
  • the piston 86 of the expansible chamber 84 is backed up by tank pressure through line 200 instead of by atmospheric pressure as in FIG. 1, but is otherwise the same as FIG. 1.
  • a normally open by-pass 300 is provided between the tank and cylinder sides of the pressure relief valve 32 Which otherwise is of the same construction as that illustrated in FIG. 1.
  • By-pass 300 includes normally open valve 302 comprising valve bore 304, spool valve 306, valve ports 308, and spring 3110.
  • One end of valve 306 is exposed to the hydraulic fluid on the high pressure side of the valve through port 312, and passage 314 so that when the pressure of the hydraulic fluid on the press side of the pressure relief valve rises, it will immediately shift valve 306 to close ports 308 and close the by-pass in synchronization with the opening of the pressure relief valve.
  • the open by-pass 300 will unload sufficient hydraulic fluid from the high pressure side of the system as the pressure rises therein so as to prevent the generation of undesirable back pressure prior to the full opening of the pressure relief valve components due to the inertia and resistance to opening movement thereof, as previously explained.
  • An adjustable stop 320 is provided for the valve 306 so that it can be set in its normally open position to provide a resistance to fluid flow through the by-pass 300 to create a pressure equal to the relief valve setting before the pressure relief valve component-s start to open.
  • valve 306 Since the pressure as it develops on the high pressure side of the system is applied to both the normally open valve 306 and the movable components of the pressure relief valve tending to close the former and open the latter, the movement of such valve elements can be synchronized so that the pressure relief valve will fully open as the valve 306 closes.
  • the valve 306 will remain closed while pressure exists, while the pressure relief valve will gradually close as it follows the pattern of the fluid displaced from the cylinders 26 as shown in FIG. 6 as the ram moves to bottom dead center position.
  • a hydraulic cushion for said die including at least one hydraulic cylinder provided with a reciprocating piston therein arrange-d to react on said die so as to bias it to its extended position; a tank of hydraulic fluid under regulated relatively low pressure, a hydraulic fluid connection between said tank and said cylinder whereby hydraulic fluid under tank pressure .is supplied from said tank to said cylinder and piston for biasing said die to its extended position but return flow through such connection is prevented, a second hydraulic fluid connection between said tank and cylinder having normally closed pressure relief valve means therein including a pilot valve and other valve means adapted to provide a bypass in the second fluid connection around the pilot valve on opening of the other valve means whereby a predetermined resistance to displacement of hydraulic fluid from the cylinder is provided so as to form a hydraulic cushion for said die upon closing of the press ram, and means to reduce the back pressure in said second fluid connection on the cylinder side of said pressure relief valve means due to resistance to opening movement of said pressure relief valve means prior to the Opening of said pressure relief valve means including
  • a hydraulic cushion for said die including at least one hydraulic cylinder provided with a reciprocating piston therein arranged to react on said die so as to bias it to its extended position; a tank of hydraulic fluid under regulated relatively low pressure, a hydraulic fluid connection between said tank and said cylinder whereby hydraulic fluid under tank pressure is supplied from said tank to said cylinder and piston for biasing said die to its extended position but return flow through such connection is prevented, a second hydraulic fluid connection between said tank and cylinder having normally closed pressure relief valve means therein whereby a predetermined resistance to displacement of hydraulic fluid from the cylinder is provided so as to form a hydraulic cushion for said die upon closing of the press ram, and means to reduce the back pressure in said second fluid connection on the cylinder side of said pressure relief valve means due to resistance to opening movement of said pressure relief valve means prior to the opening of said pressure relief valve means including a third hydraulic fluid connection between the tank and cylinder, a spool valve positioned in said third hydraulic fluid connection, resilient means biasing said s
  • a crank type press having a ram, a die, a hydraulic cushion for said die including at least one hydraulic cylinder provided with -a reciprocating piston therein arranged to react on said die so as to bias it to its extended position; a tank of hydraulic fluid under regulated, relati-vely low pressure, a hydraulic fluid conduit between said tank and said cylinder, valve structure positioned between said tank and hydraulic cylinder in said hydraulic fluid conduit for regulating the flow of hydraulic fluid between said tank and said cylinder including a first passage extending therethrough in communication at the opposite ends thereof with said conduit, a check valve in said first passage for permitting hydraulic fluid flow only from said tank to said cylinder, a second passage in said valve structure in communication at the opposite ends thereof with said conduit, a pressure relief valve in said second passage including a cylindrical valve sleeve, a valve member reciprocably mounted in said valve sleeve, means biasing the valve member into closed position with respect to said second passage responsive to high pressure in said cylinder to open said second passage, a restricted opening through said valve member,
  • a crank type press having a ram, a die, a hydraulic cushion for said die including at least one hydraulic cylinder provided with a reciprocating piston therein arranged to react on said die so as to bias it to its extended position; a tank of hydraulic fluid under regulated, relatively low pressure, a hydraulic fluid conduit between said tank and said cylinder, valve structure positioned between said tank and hydraulic cylinder in said hydraulic fluid conduit for regulating the flow of hydraulic fluid between said tank and said cylinder including a first passage extending therethrough in communication at the opposite ends thereof with said conduit, a check valve in said first passage for permit-ting hydraulic fluid flow only from said tank to said cylinder, a second passage in said valve structure in communication at the opposite ends thereof wit-h said conduits, a pressure relief valve in said second passage including a cylindrical valve sleeve, a valve member reciprocally mounted in said valve sleeve, resilient means biasing the valve member into closed position with respect to said second passage responsive to high pressure in said cylinder to open said second passage, a restricted opening through said valve

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Presses And Accessory Devices Thereof (AREA)
US335730A 1964-01-06 1964-01-06 Hydraulic cushion for dies Expired - Lifetime US3268220A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US335730A US3268220A (en) 1964-01-06 1964-01-06 Hydraulic cushion for dies
GB49883/64A GB1074240A (en) 1964-01-06 1964-12-08 Improvements in or relating to hydraulic cushion for dies
DE19641502334 DE1502334A1 (de) 1964-01-06 1964-12-29 Hydraulisches Federkissen fuer den Gesenkteil einer Kurbelpresse

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US335730A US3268220A (en) 1964-01-06 1964-01-06 Hydraulic cushion for dies

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US3268220A true US3268220A (en) 1966-08-23

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DE (1) DE1502334A1 (de)
GB (1) GB1074240A (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3362210A (en) * 1964-12-16 1968-01-09 James V. Perrone Control for die pads, presses and the like
US3362207A (en) * 1966-08-23 1968-01-09 James V. Perrone Hydraulic control system
US4013093A (en) * 1974-11-18 1977-03-22 Massey-Ferguson Services N.V. Hydraulic valves
WO1981003531A1 (en) * 1980-05-27 1981-12-10 Caterpillar Tractor Co A recoil and positioning mechanism
US5735201A (en) * 1994-12-21 1998-04-07 Toyota Jidosha Kabushiki Kaisha Apparatus including mutually communicating hydraulic cylinders for even distribution of blank-holding force on pressing machine
US20080236678A1 (en) * 2007-03-27 2008-10-02 Volvo Construction Equipment Holding Sweden Ab. Relief valve for heavy equipment
CN102155449A (zh) * 2011-03-31 2011-08-17 太原理工大学 数字控制的先导型比例流量阀

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1577446A (en) * 1924-12-19 1926-03-23 Brown Stewart Cushion for die-press draw rings
US2938718A (en) * 1959-05-26 1960-05-31 Floyd M Williamson Hydraulic cushion for the die pad of a ram type press
USRE25027E (en) * 1961-08-15 Circulating systems for hydraulic liquid
US3077898A (en) * 1959-01-28 1963-02-19 Racine Hydraulics And Machiner Fluid relief valve
US3124343A (en) * 1964-03-10 Hydraulic cushion for die pads in presses
US3147723A (en) * 1961-05-24 1964-09-08 Dro Engineering Company Di Hydraulic control system for die pads in presses

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE25027E (en) * 1961-08-15 Circulating systems for hydraulic liquid
US3124343A (en) * 1964-03-10 Hydraulic cushion for die pads in presses
US1577446A (en) * 1924-12-19 1926-03-23 Brown Stewart Cushion for die-press draw rings
US3077898A (en) * 1959-01-28 1963-02-19 Racine Hydraulics And Machiner Fluid relief valve
US2938718A (en) * 1959-05-26 1960-05-31 Floyd M Williamson Hydraulic cushion for the die pad of a ram type press
US3147723A (en) * 1961-05-24 1964-09-08 Dro Engineering Company Di Hydraulic control system for die pads in presses

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3362210A (en) * 1964-12-16 1968-01-09 James V. Perrone Control for die pads, presses and the like
US3362207A (en) * 1966-08-23 1968-01-09 James V. Perrone Hydraulic control system
US4013093A (en) * 1974-11-18 1977-03-22 Massey-Ferguson Services N.V. Hydraulic valves
WO1981003531A1 (en) * 1980-05-27 1981-12-10 Caterpillar Tractor Co A recoil and positioning mechanism
US5735201A (en) * 1994-12-21 1998-04-07 Toyota Jidosha Kabushiki Kaisha Apparatus including mutually communicating hydraulic cylinders for even distribution of blank-holding force on pressing machine
US20080236678A1 (en) * 2007-03-27 2008-10-02 Volvo Construction Equipment Holding Sweden Ab. Relief valve for heavy equipment
CN102155449A (zh) * 2011-03-31 2011-08-17 太原理工大学 数字控制的先导型比例流量阀
CN102155449B (zh) * 2011-03-31 2015-11-25 太原理工大学 数字控制的先导型比例流量阀

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Publication number Publication date
DE1502334A1 (de) 1969-04-10
GB1074240A (en) 1967-07-05

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