US3768400A - Press having means to prevent skewing movement of the ram - Google Patents

Press having means to prevent skewing movement of the ram Download PDF

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Publication number
US3768400A
US3768400A US00219073A US3768400DA US3768400A US 3768400 A US3768400 A US 3768400A US 00219073 A US00219073 A US 00219073A US 3768400D A US3768400D A US 3768400DA US 3768400 A US3768400 A US 3768400A
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United States
Prior art keywords
ram
motors
opposing
cylinder
movement
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Expired - Lifetime
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US00219073A
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English (en)
Inventor
W Gygli
E Hanni
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Haemmerle AG Maschinenfabrik
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Haemmerle AG Maschinenfabrik
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/16—Control arrangements for fluid-driven presses
    • B30B15/24—Control arrangements for fluid-driven presses controlling the movement of a plurality of actuating members to maintain parallel movement of the platen or press beam
    • B30B15/245—Control arrangements for fluid-driven presses controlling the movement of a plurality of actuating members to maintain parallel movement of the platen or press beam using auxiliary cylinder and piston means as actuating members
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/16—Control arrangements for fluid-driven presses
    • B30B15/163—Control arrangements for fluid-driven presses for accumulator-driven presses

Definitions

  • ABSTRACT A press wherein there is provided an arrangement of opposing cylinder-piston motors to prevent skewing of the press ram or plaste n when it is moved in its work stroke by cylinder-piston work motors.
  • the opposing motors comprise a single acting motor and a double acting motor, each connected to an end of the ram in opposing relation to the work motors.
  • the single acting cylinder is serially connected to the rod end of the double acting motor.
  • the opposing motors are connected to a pressure accumulator which provides the opposing counter-pressure to overcome skewing movements of the ram and also provides pressure fluid to the opposing motors to retract the ram.
  • the ram is provided with an extension which is perpendicular thereto.
  • Pressurized cylinder-piston motors are arranged on opposing sides of the extension to maintain it in a position wherein extension to actuate the valves to control the rate of flow to the work motors in the sense to eliminate the skewing movement and to resolve the ram to its parallel position.
  • the present invention refers to a press having a ram or platen which is actuated at both ends by hydraulic or pneumatic working cyliners.
  • a disadvantage of this arrangement consists in the fact that the entire oil quantity must be passed through the narrow control passages. It is not possible to make the through cross-section of the control passages larger, since a precise control involving reactions to the smallest of skew positions would then no longer be assured.
  • the object of the present invention is to propose a press for which these prerequisites are fulfilled, but for which in addition the ram is held in a position parallel to the worktable during the rapid forward travel and during the return stroke.
  • this is achieved through the fact that at least one conventional throttle control valve means with steplessly adjustable through cross-section is provided which is connectable to the individual working cylinders during the working stroke for altering individually the amount of pressure medium applied to them, and that at least two auxiliary pistons operating in hydraulic or pneumatic cylinders are provided which are arranged at a distance from each other in the area of and operatively connected to the ram in order to exert a counterpressure on the ram which is responsive to the forces occurring at the ram ends, and which counteract a skewed position of the ram during the rapid forward travel and during its return stroke.
  • the same pistons may be used to effect a return of the ram.
  • the correction of a skewed position of the ram which may occur nevertheless, e.g., as a result of oil lost through leakage, can be accomplished by aligning the ram when it has reached a predetermined extreme position and at the same time bringing all of the counterpressures to the same value and-thereby equalizing the same.
  • one singleacting and one double-acting cylinder can be provided, whereby the cylinder space of the single-acting auxiliary cylinder is serially connected to the opposed cylinder space of the double-acting auxiliary cylinder.
  • the other cylinder space of the double-acting auxiliary cylinder is connected to a hydraulic accumulator whereby a connecting line exists between the two cylinder spaces of the double-acting auxiliary cylinder in which an optionally closable valve can be fitted.
  • the valve is located in the area of the lower predetermined extreme position of the ram so that the ram can catuate it in the sense of opening when it reaches thisextreme position and equalize the pressure at both ends of the double cylinder.
  • auxiliary pistons can be provided which are supported in cylinders two of which are mounted on either side of a ram extension piece projecting downwards whereby each of the four piston rods which project perpendicular to the direction of movement of the ram and is provided on its end with a rotatable roller which can be brought to rest against the ram extension.
  • two control valves are provided which are arranged one on either side of the extension, and are responsive to a skewing movement of the ram to control the flow of fluid to the several ram cylinders, and thereby synchronize the movement of the pistons connected to the ram.
  • stops can be provided for the auxiliary pistons which only permit the rollers to be moved up to the point of contacting the extension.
  • FIG. 1 is a schematic view of the hydraulic circuit and the several components of the press
  • FIG. 2 is a schematic view showing the operative relationship of the cylinders to the ram or platen
  • FIG. 3 is a front view of a press illustrating another embodiment of the invention.
  • two actuating pistons l and 2 are connected to the ram or platen R with their piston rods 3 and 4 for rapid forward travel as well as for transmitting working pressure force to the ram.
  • the working pressure for the press is generated in a highpressure pump 5 which is driven by a motor 6.
  • a lowpressure pump 7 with high discharge rate, driven by the same motor, is provided for the rapid forward travel of the ram.
  • the pistons l and 2 are located in cylinders 8 and 9, which are connected to a throttling control valve means 14 by means of pipe 10 and 11 and check valves 12 and 13 therein.
  • the control valve is connected to the high pressure pump 5 by a pipe 15 which contains a three-way reversing valve 16.
  • Two branch pipes 17 and 18 having check valves. 19 and 20 therein connect pipe 10 and 11 to reversing valve 16 in sump tank 21.
  • Two further branch pipes 22 and 23 which likewise connect to the pipes 10 and 11 serve to carry the oil from the low pressure pump 7 via a pipe 26 nd via two check valves 24 and 25.
  • a branch pipe 27 connects the pipe 26 with a bypass valve 28 from which the oil is led via a check valve 29 into the supply tank 21.
  • a pressure accumulator 33 is connected by means of a pipe 31 in which a check valve 32 is installed to a selector valve 30 which connects the pipe 31 optionally to the sump tank 21 or to the high-pressure pump 5.
  • a single-acting piston 34 located in a cylinder 35 and a double-acting piston 36 mounted in a cylinder 37.
  • the cylinder 37 is divided by piston 36 into opposing expansible spaces 37a and 37b.
  • Cylinder space 37b is connected by a pipe 38 to the pressure accumulator 33.
  • a pipe 39 serially connects cylinder space 35a of the single-acting cylinder 35.
  • a connecting pipe 40 is provided which joins the two cylinder spaces 37a and 37b.
  • pistons 34 and 36 may be moved upwardly until they come in contact with ram R when it is in its upper extreme position.
  • FIG. 2 shows in dotted lines extensions connected to ram R which are positions with respect to pistons 34 and 36 to be contacted by them when actuated upwardly. It is obvious that pistons 34 and 36 may be arranged to contact ram R directly.
  • valve means 41a and 41b are actuated by an adjustable actuating means 42 movable with ram R to position II for equalizing the pressures in cylinder spaces 35a, 37a and 37b and thereby restoring the relative positions of pistons 34 and 36 which may have been disturbed due to sealing leakage.
  • Means 42 actuates the valve through its control member 43 connected to the valve members 41a and 41b.
  • the selector valve 30 When the press is started up, the selector valve 30 is first switched to position II, thus connecting the highpressure pump via pipe 31 and check valve 32 to the pressure accumulator 33 which it charges.
  • the valve members 41a and 41b are in position I, i.e., they shut off the pipe 40, so that the two pistons 34 and 36 are run to their uppermost extreme position to contact ram R directly or to operatively contact it by extension means connected thereto.
  • a counterpressure is built up, which is diverted via pipe 39 into the cylinder space 37a of the cylinder 37 and from cylinder space 37b via pipe 38 into the pressure accumulator 33.
  • the connection of the cylinder space 35 with the cylinder space 37a via pipe 39 produces a compulsory slaved movement of the pistons 34 and 36. This serves to support the ram and hold it in a parallel position.
  • valves 41a, 41b are reclosed and the reversing valve 16 switched to position I.
  • This allows the pressure in the cylinders 8 and 9 to be let off through pipes 17 and 18 into the sump tank 21 as the ram moves upward under the influence of the highly compressed oil in the accumulator 33 acting on pistons 34 and 36.
  • the parallel control is accomplished again by means of the pistons 34 and 36 in analogous fashion to that described for the rapid forward travel.
  • the entire procedure as described starts over again, in that the valves 16 and 28 are reversed in order to actuate the ram in rapid forward travel toward the workpiece.
  • a parallel guidance of the ram during the working stroke is achieved by the control valve 14, which controls the oil supply to the cylinders 8 and 9. But during the rapid forward travel under low-pressure pump 7 and the ram return stroke, the oil does not need to flow through the narrow cross-sections or passages of the control valve 14, thus making possible an increased speed in the ram movement. A cumulative skewed position of the ram caused by oil leakage losses is not possible, since the ram is restraightened after every working stroke in compulsory fashion by means of the actuation of valves 41a and 41b.
  • two columns 101 and 102 are supported in the frame 103 of the press; these columns house the working cylinders (not shown in detail which actuate the ram guide elements 104 and 105 which are carried by the columns.
  • the ram 106 is joined to these guide elements 104 and 105 and carries on its underside an upper tool 107 which acts in conjunction with a lower tool 108 arranged on the frame 103 of the press.
  • the guide elements 104 and 105 assume the guidance of the ram toward the front and the rear, while for its parallel guidance, a ram extension 109 is provided in the form of a massive steel plate which can, for example, be attached to the ram by means of bolts 110.
  • auxiliary cylinders Illa-111d are mounted on the frame 103 of the press.
  • the two cylinders 111a and 1 11b are mounted on one side of the extension 109 and the two other cylinders l 11c and 111d are mounted on the other side of the extension 109, all in such a way that the piston rods 113 of the pistons 112 supported in them project all the way to the extension 109 in a direction perpendicular to the path of the movement of the ram 106.
  • Each of the piston rods 113 is provided with a fork 114 in which a roller 116 is supported so that it is free to rotate about an axle 115.
  • the arrangement is made in such a way that, in the case of a displacement of the pistons 112 in the cylinders 111 in the direction of the extension 109, the rollers 116 come to rest against the extension 109 by piston 112 contacting an adjustable stop 112a.
  • the ram 106 In the rest position of the press, the ram 106 is at the upper stop as shown in the drawing, so that a workpiece to be worked can be introduced between the tools 107 and 108. Now the control valves 117 are bypassed and the pistons 112 in the cylinders 111 are placed under pressure. This causes the pistons 112 to move against their stops 112a, with the result that the rollers 116 contact extension 109 of the ram 106, so that in the subsequent rapid forward travel of the ram 106 when the working cylinders are supplied directly by a lowpressure pump with a high discharge rate, extension 109 is guided by the rollers 116 and forced to remain in a position parallel to the frame.
  • the control valves are switched into the supply line of the working cylinders.
  • the parallel position of the ram 106 is controlled by the individual regulation of the pressure 'medium supplied to the working cylinders, in that a deviation of the extension 109 caused by a skewing of the ram actuates one of the control rods 118 of the control valves 1 17, thus efl'ecting either a throttling of the leading cylinder or an acceleration of the lagging one.
  • a ram pressure working cylinder-piston motors connected to each end area of saidram to move it in a work stroke, said motors constituting working and opposing motors and comprising a first single acting cylinder operatively engaging one end area of the ram and a second double acting cylinder operatively engaging the opposing end area of said ram, to oppose the work stroke movement under the influence of the working motors, a pressure fluid supply line connected to each motor to supply working fluid thereto, throttle valve means in each of said lines to control the rate of flow therethrough, conduit means for serially connecting the cylinders of said opposing motors for transmitting an abnormal movement of pistons due to the skewing of the ram to the other opposing pistons, said conduit means including means for connecting said single acting cylinder to the piston rod end of said double acting cylinder and thereby compensating for the abnormal movement to restore the synchronous movement of the work motors for movement in the work stroke, a pressure accumulator connected to said opposing motors to pressurize said motors
  • a ram pressure fluid working cylinderpiston motors connected to said ram to move it in a work stroke, a plurality of opposing cylinder-piston motors operatively connected to the ram to oppose its movement under the influence of the work motors, one of said plurality of motors being connected to each end area of the ram so that opposing motors comprise a single acting cylinder operatively engaging one end area of the ram and a second double acting cylinder operatively engaging an opposing area of the ram, a pressure fluid supply line connected to each motor to supply working fluid thereto,.throttle valve means in each of said lines to control the rate of flow therethrough, conduit means connecting said single acting cylinder to the piston rod end of said double acting cylinder which also serially connects said opposing motors for transmitting an abnormal movement of the pistons due to the skewing of the ram to the other opposing pistons to compensate such abnormal movement and thereby restore the synchronous movement of the work motors and a pressure accumulator connected to
  • a press as claimed in claim 2 wherein a pipe line is provided to connect both ends of the double acting cylinder, and there is further provided a normally closed valve means in said pipe line to isolate said ends, and means to open said valve means and thereby equalize the pressure in the opposing motor cylinders, said valve means including valve adjusting means responsive to ram movement and said valve actuating means opening said valve means at a predetermined stroke of theram.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Press Drives And Press Lines (AREA)
US00219073A 1971-01-22 1972-01-19 Press having means to prevent skewing movement of the ram Expired - Lifetime US3768400A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT51671A AT307235B (de) 1971-01-22 1971-01-22 Hydraulische oder pneumatische Presse mit zwei einseitig wirkenden Arbeitszylindern

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2674460A1 (fr) * 1991-03-27 1992-10-02 Mercier J Perfectionnements aux presses hydrauliques, en particulier aux presses-plieuses a tole.
US20030010077A1 (en) * 1999-09-03 2003-01-16 Komatsu Ltd. Slide inclination correcting method and slide inclination correcting apparatus in press machinery
US7269949B1 (en) * 2004-09-24 2007-09-18 Davor Petricio Yaksic Synchronizing hydraulic cylinders
US20160136710A1 (en) * 2013-06-19 2016-05-19 Bruderer Ag Method for bending the machine bed of a stamping press, and stamping press
US9816539B1 (en) 2013-03-19 2017-11-14 Davor Petricio Yaksic Motion control
CN116274623A (zh) * 2023-05-18 2023-06-23 江苏万恒铸业有限公司 一种防刀头歪斜的高强度铸钢件冲孔机及其防断裂方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2377007A (en) * 1941-09-29 1945-05-29 American Steel Foundries Equalizing hydraulic ram travel
US2809543A (en) * 1953-04-07 1957-10-15 Baldwin Lima Hamilton Corp Compensating system for presses
US2809542A (en) * 1953-02-17 1957-10-15 Baldwin Lima Hamilton Corp Compensating system for presses
FR1403276A (fr) * 1964-07-09 1965-06-18 Schwermaschb Heinrich Rau Veb Dispositif de correction pour presses hydrauliques à longs plateaux
US3664174A (en) * 1969-05-28 1972-05-23 Hammerla Ag Maschinenfabrik Sheet metal working machine

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2377007A (en) * 1941-09-29 1945-05-29 American Steel Foundries Equalizing hydraulic ram travel
US2809542A (en) * 1953-02-17 1957-10-15 Baldwin Lima Hamilton Corp Compensating system for presses
US2809543A (en) * 1953-04-07 1957-10-15 Baldwin Lima Hamilton Corp Compensating system for presses
FR1403276A (fr) * 1964-07-09 1965-06-18 Schwermaschb Heinrich Rau Veb Dispositif de correction pour presses hydrauliques à longs plateaux
US3664174A (en) * 1969-05-28 1972-05-23 Hammerla Ag Maschinenfabrik Sheet metal working machine

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2674460A1 (fr) * 1991-03-27 1992-10-02 Mercier J Perfectionnements aux presses hydrauliques, en particulier aux presses-plieuses a tole.
US20030010077A1 (en) * 1999-09-03 2003-01-16 Komatsu Ltd. Slide inclination correcting method and slide inclination correcting apparatus in press machinery
US6595122B1 (en) * 1999-09-03 2003-07-22 Komatsu, Ltd. Slide inclination correcting method and slide inclination correcting apparatus in press machinery
US6655267B2 (en) * 1999-09-03 2003-12-02 Komatsu Ltd. Slide inclination correcting method and slide inclination correcting apparatus in press machinery
US7269949B1 (en) * 2004-09-24 2007-09-18 Davor Petricio Yaksic Synchronizing hydraulic cylinders
US9816539B1 (en) 2013-03-19 2017-11-14 Davor Petricio Yaksic Motion control
US20160136710A1 (en) * 2013-06-19 2016-05-19 Bruderer Ag Method for bending the machine bed of a stamping press, and stamping press
CN116274623A (zh) * 2023-05-18 2023-06-23 江苏万恒铸业有限公司 一种防刀头歪斜的高强度铸钢件冲孔机及其防断裂方法
CN116274623B (zh) * 2023-05-18 2023-09-08 江苏万恒铸业有限公司 一种防刀头歪斜的高强度铸钢件冲孔机及其防断裂方法

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AT307235B (de) 1973-05-10

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