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Hydraulic press brake

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Publication number
US3914975A
US3914975A US51294374A US3914975A US 3914975 A US3914975 A US 3914975A US 51294374 A US51294374 A US 51294374A US 3914975 A US3914975 A US 3914975A
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Prior art keywords
means
hydraulic
die
punch
bending
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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
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Susumu Kawano
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Amada Co Ltd
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Amada Co Ltd
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    • 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
    • B21D5/00Bending sheet metal along straight lines, e.g. to form simple curves
    • B21D5/02Bending sheet metal along straight lines, e.g. to form simple curves on press brakes without making use of clamping means
    • B21D5/0272Deflection compensating means

Abstract

A hydraulic press brake is disclosed having a stationary die cooperating with a movable die or punch to perform a bending operation on an elongated workpiece. Movement of the punch is effected by means of a pair of first hydraulic piston-cylinder units each of which is located proximate to one end of the punch. At least one second hydraulic piston-cylinder unit acts on the stationary die at a location intermediate the ends thereof to impart a convex bend to the fixed die to compensate for any concave bending of the movable die during a bending operation, thereby maintaining the surfaces of the fixed and movable dies substantially parallel. Pressurized hydraulic fluid is fed to the first and second hydraulic piston-cylinder units through feed conduits leading from a common pump, with a pressure reducing valve being interposed in the feed conduits between the pump and the second hydraulic piston-cylinder unit.

Description

United States Patent [1 1 Kawano Oct. 28, 1975 [73] Assignee: Amada Company Limited, lsehara,

Japan [22] Filed: Oct. 7, 1974 [21] Appl. No.: 512,943

Related U.S. Application Data [63] Continuation-impart of Ser. No. 358,125, May 5, 1973, abandoned, which is a continuation of Ser. No. 209,771, Dec. 20, 1971, abandoned.

[30] Foreign Application Priority Data FOREIGN PATENTS OR APPLICATIONS 1,452,818 11/1970 Germany 72/389 Primary Examiner-C. W. Lanham Assistant Examiner-Gene P. Crosby Attorney, Agent, or FirmThompson, Birch, Gauthier & Samuel [5 7] ABSTRACT A hydraulic press brake is disclosed having a stationary die cooperating with a movable die or punch to perform a bending operation on an elongated workpiece. Movement of the punch is effected by means of a pair of first hydraulic piston-cylinder units each of which is located proximate to one end of the punch. At least one second hydraulic piston-cylinder unit acts on the stationary die at a location intermediate the ends thereof to impart a convex bend to the fixed die to compensate for any concave bending of the movable die during a bending operation, thereby maintaining the surfaces of the fixed and movable dies substantially parallel. Pressurized hydraulic fluid is fed to the first and second hydraulic piston-cylinder units through feed conduits leading from a common pump, with a pressure reducing valve being interposed in the feed conduits between the pump and the second hydraulic piston-cylinder unit.

2 Claims, 5 Drawing Figures US. Patent Oct. 28, 1975 Sheet 1 of2 3,914,975

FIG.

FIG. 5

US. Patent Oct. 28, 1975 Sheet2of2 3,914,975

FIG. 3

INVENTOR MMW ATTORNEYS HYDRAULIC PRESS BRAKE DESCRIPTION or THEINVENTION mechanical characteristics of the workpiece, e.g., tensile strength, elastic limit, yield point, as well as the resilient characteristics of the workpiece. For example, when a conventional press brake is operated with use of an elongated punch and an elongated die, the downward forces on the punch are exerted at the ends respectively of the ram supporting the punch and the stationary frame supporting the die. Thus, the punch has a tendency to warp upwardly in a concave manner, whereas the stationary die has a tendency to warp downwardly in a concave manner, because of the resistance of the workpiece to bending. As a result, the lower surface of the punch tends to part from the upper surface of the die. The resulting product is distorted (as shown in FIG. 2) with warps and 7 at the central portions thereof.

Attempts have been made at solving the above problem by increasing the thickness of the central portion of the ram supporting the movable punch. This arrangement can only be employed, however, for the bending of certain materials of a specified bending resistance. Inaccurate bends are still likely to result when materials of different kinds are being bent with greater resistances to bending.

A general object of the present invention is the provision of novel and improved means for obviating the problems noted above. This and other more specific objects and advantages of the present invention will become more apparent as the description proceeds with the aid of the accompanying drawings wherein:

FIG. 1 is a front view, with portions broken away, of a hydraulic press brake embodying the concepts of the present invention, and including a schematic illustration of the hydraulic system;

FIG. 2 is a perspective view of a typical product bent in accordance with conventional techniques;

FIG. 3 is a perspective view showing a typical punch and cooperating lower die;

FIG. 4 is a view in side elevation of the apparatus shown in FIG. I; and

FIG. 5 is a sectional view of a reducing valve employed in the hydraulic system schematically depicted in FIG. 1.

With reference now to the drawings, 9 denotes a lower stationary frame carrying a lower die 3. Reference characters l1, l3 and denote hydraulic mechanisms or cylinders which are mounted on a rigid plate 16 secured to the frame 9 at locations intermediate the ends of the die 3. The hydraulic mechanisms 11, 13, 15 are provided respectively with piston and piston rods 11p, 13p and 15p which exert an upward force on the die 3 through the frame 9. In the embodiment herein disclosed, three such hydraulic mechanisms are disclosed, although it will be appreciated that this number may be varied without departing from the spirit and scope of the invention.

The .ram 17 carrying the upper punch or die 1 is constructed with athicker central portion in accordance with known techniquesrto minimize any upward or concave warpingduring a bending operation.

Theframe 9 islpivotally carried on horizontal fixed pins 19, 21, the said frame having an elongated opening or slot 23 to accommodate pine 21. This arrangement permits the frame 9 to bend upwardly or convexly when an upward force is exerted thereon by the hydraulic mechanisms 11, 13 and. 15.

Hydraulic mechanisms 33, 35 are positioned to exert downward forces on the ends of the ram 17 carrying punch l. A pump P is driven by motor M and draws hydraulic fluid from a tank T. The fluid is pumped through conduits 30, 29 to mechanism 33, through conduits 30, 31 to mechanism 35, and through conduits 30, 29, 27 and thence through conduits 39, 41 and 43 to hydraulic mechanisms 15, 13 and 11. A pressure reducing valve 25 is located in conduit 27 between the hydraulic mechanisms 15, l3, l1 and pump P.

The pressure reducing valve 25 is of a type wherein the amount of pressure reduction may be optionally selected so that any desired pressure may be obtained in proportion to the pressure being applied to the hydraulic mechanisms 33, 35. FIG. 5 shows one such typical pressure reducing valve 25 wherein P is a high pressure inlet, P is a reduced pressure outlet, P is a port for a pressure gauge, 1 is a piston and S is a spring. With this arrangement, any increase (or decrease) in pressure P is accompanied by a proportional change in pressure P Although not shown, it will be further understood that the conduits 37, 39, 41 and 43 are provided with appropriate check valves.

In view of the above, it will now be seen that since the stationary frame 9 and the lower die 3 are pressed upwards by the hydraulic cylinders 11, 13 and 15, during a bending operation, they do not warp downward as shown by C in FIG. 1, but warp as shown by curve C,, so as to follow the warp of the punch 1 and the ram 17 as shown by curve C Thus the hydraulic press brake of the present invention is characterized in that the upward warp of the stationary frame and the die carried thereon follows the warp of the ram and the punch to avoid such oppositely directed warps of the upper and the lower dies which might otherwise separate the punch from the lower die at the center, thereby obviating the defects that characterize products bent in accordance with conventional techniques as shown in FIG. 2.

I claim:

1. A hydraulic press brake comprising: stationary frame means supporting an elongated die; movable ram means carrying an elongated punch, said punch being adapted to cooperate with said die in performing a bending operation on an elongated workpiece positioned therebetween; first hydraulically actuated means acting on said movable ram means at locations proximate to the ends thereof for moving said ram means and punch towards said stationary frame and elongated die during a bending operation; second hudraulically actuated means acting on said stationary frame means at a location intermediate the ends of the die supported thereon, said second hydraulically actuated means being operative to bend said stationary draulic fluid being applied to said second hydraulically actuated means in proportion to the pressure of the hydraulic fluid being applied to said first hydraulically actuated means.

2. The apparatus as claimed in claim 1 wherein said first and second hydraulically actuated means comprise piston-cylinder assemblies.

Claims (2)

1. A hydraulic press brake comprising: stationary frame means supporting an elongated die; movable ram means carrying an elongated punch, said punch being adapted to cooperate with said die in performing a bending operation on an elongated workpiece positioned therebetween; first hydraulically actuated means acting on said movable ram means at locations proximate to the ends thereof for moviNg said ram means and punch towards said stationary frame and elongated die during a bending operation; second hydraulically actuated means acting on said stationary frame means at a location intermediate the ends of the die supported thereon, said second hydraulically actuated means being operative to bend said stationary frame means and die convexly to thereby compensate for concave bending of said punch and ram means during a bending operation; hydraulic pump means; conduit means connecting said hydraulic pump means to said first and second hydraulically actuated means; and pressure reducing valve means in said conduit means between said pump means and said second hydraulically actuated means, said pressure reducing valve means being operative to reduce the pressure of the hydraulic fluid being applied to said second hydraulically actuated means in proportion to the pressure of the hydraulic fluid being applied to said first hydraulically actuated means.
2. The apparatus as claimed in claim 1 wherein said first and second hydraulically actuated means comprise piston-cylinder assemblies.
US3914975A 1970-12-25 1974-10-07 Hydraulic press brake Expired - Lifetime US3914975A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP11768570 1970-12-25
US35812573 true 1973-05-05 1973-05-05
US3914975A US3914975A (en) 1970-12-25 1974-10-07 Hydraulic press brake

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US3914975A US3914975A (en) 1970-12-25 1974-10-07 Hydraulic press brake

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Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4016742A (en) * 1970-12-25 1977-04-12 Seiji Shiokawa Press-forming apparatus
US4098109A (en) * 1976-04-13 1978-07-04 Promecam Sisson-Lehmann Bending press or similar machine tool
US4332536A (en) * 1980-04-09 1982-06-01 Nrm Corporation Hydraulic tire press
US4347727A (en) * 1980-07-28 1982-09-07 Galiger Barry J Programmable upward-stroke insert mechanism for bending brakes and method of use
US4390334A (en) * 1980-04-09 1983-06-28 Nrm Corporation Hydraulic tire press
US4557792A (en) * 1983-04-15 1985-12-10 Hitachi, Ltd. Hot press
US4563139A (en) * 1983-01-27 1986-01-07 Kabushiki Kaisha Kobe Seiko Sho Mold clamping mechanism for tire curing machines
US4580434A (en) * 1983-11-14 1986-04-08 Cincinnati Incorporated Deflection compensating assembly for a press brake
US4702688A (en) * 1985-04-15 1987-10-27 Bernd Schenk Apparatus for producing articles from a synthetic resin
US4825681A (en) * 1987-01-22 1989-05-02 Kenneth L. Smedberg Pneumatic press counterbalance and cushion construction
US4860571A (en) * 1986-09-26 1989-08-29 Kenneth L. Smedberg Power press with improved cushioning system
US4875849A (en) * 1988-03-14 1989-10-24 Huang Jin S Rubber shaping machine
US4918956A (en) * 1987-08-27 1990-04-24 The Minster Machine Company Monitorable and compensatable feedback tool and control system for a press using a solid tool backup element
US4939918A (en) * 1987-08-27 1990-07-10 The Minster Machine Company Monitorable and compensatable feedback tool and control system for a press
US4945742A (en) * 1987-08-27 1990-08-07 The Minster Machine Company Monitorable and compensatable feedback tool and control system for a press
US5067340A (en) * 1988-05-05 1991-11-26 Macgregor Donald C Precision press brake
US5193452A (en) * 1989-09-11 1993-03-16 Willem Dieperink Folding press with deflection compensating means
US5347840A (en) * 1991-08-17 1994-09-20 L. Schuler Gmbh Press comprising a press table and a sliding table
US5930888A (en) * 1995-12-01 1999-08-03 Ralph C. Ball Device to hold, dispense and install slotted weights used with fishing line
FR2782942A1 (en) * 1998-09-09 2000-03-10 Amada Europ Sa press brake is active lower apron
DE3943349C2 (en) * 1988-12-29 2001-08-23 Amada Co Bending machine
US20040099038A1 (en) * 2002-10-17 2004-05-27 Alberto Arduino Bending press with a substantially undeformable toolholder beam
US20040103707A1 (en) * 2000-12-12 2004-06-03 Andreas Winters Internal high pressure forming device and method and corresponding tool system
WO2013072859A1 (en) * 2011-11-15 2013-05-23 Adira, S.A. Beam for deformation compensation in press brakes
EP2682198A1 (en) * 2012-07-06 2014-01-08 Gasparini Industries S.r.l. Cambering device in bending presses
US20150273555A1 (en) * 2012-10-18 2015-10-01 Nivora Ip B.V. Spring Means for Device for Working Sheet-Like Material
USD807933S1 (en) * 2015-08-14 2018-01-16 Henri Emil Louis Maurice Zermatten Tool for a press brake

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3163105A (en) * 1962-06-11 1964-12-29 Pacific Ind Mfg Co Pivotal drive connection
US3550425A (en) * 1967-07-26 1970-12-29 Promecan Sisson Lehmann Hydraulic machine for deforming sheet metal
US3587286A (en) * 1968-12-06 1971-06-28 Rezso Fritsch Press brake
US3668919A (en) * 1969-09-12 1972-06-13 Toshio Hongo Combination hydraulic shearing and pressbrake machine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3163105A (en) * 1962-06-11 1964-12-29 Pacific Ind Mfg Co Pivotal drive connection
US3550425A (en) * 1967-07-26 1970-12-29 Promecan Sisson Lehmann Hydraulic machine for deforming sheet metal
US3587286A (en) * 1968-12-06 1971-06-28 Rezso Fritsch Press brake
US3668919A (en) * 1969-09-12 1972-06-13 Toshio Hongo Combination hydraulic shearing and pressbrake machine

Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4016742A (en) * 1970-12-25 1977-04-12 Seiji Shiokawa Press-forming apparatus
US4098109A (en) * 1976-04-13 1978-07-04 Promecam Sisson-Lehmann Bending press or similar machine tool
US4332536A (en) * 1980-04-09 1982-06-01 Nrm Corporation Hydraulic tire press
US4390334A (en) * 1980-04-09 1983-06-28 Nrm Corporation Hydraulic tire press
US4347727A (en) * 1980-07-28 1982-09-07 Galiger Barry J Programmable upward-stroke insert mechanism for bending brakes and method of use
US4563139A (en) * 1983-01-27 1986-01-07 Kabushiki Kaisha Kobe Seiko Sho Mold clamping mechanism for tire curing machines
US4686129A (en) * 1983-01-27 1987-08-11 Kabushiki Kaisha Kobe Seiko Sho Mold clamping mechanism for tire curing machines
US4557792A (en) * 1983-04-15 1985-12-10 Hitachi, Ltd. Hot press
US4580434A (en) * 1983-11-14 1986-04-08 Cincinnati Incorporated Deflection compensating assembly for a press brake
US4702688A (en) * 1985-04-15 1987-10-27 Bernd Schenk Apparatus for producing articles from a synthetic resin
US4860571A (en) * 1986-09-26 1989-08-29 Kenneth L. Smedberg Power press with improved cushioning system
US4825681A (en) * 1987-01-22 1989-05-02 Kenneth L. Smedberg Pneumatic press counterbalance and cushion construction
US4918956A (en) * 1987-08-27 1990-04-24 The Minster Machine Company Monitorable and compensatable feedback tool and control system for a press using a solid tool backup element
US4939918A (en) * 1987-08-27 1990-07-10 The Minster Machine Company Monitorable and compensatable feedback tool and control system for a press
US4945742A (en) * 1987-08-27 1990-08-07 The Minster Machine Company Monitorable and compensatable feedback tool and control system for a press
US4875849A (en) * 1988-03-14 1989-10-24 Huang Jin S Rubber shaping machine
US5067340A (en) * 1988-05-05 1991-11-26 Macgregor Donald C Precision press brake
DE3943349C2 (en) * 1988-12-29 2001-08-23 Amada Co Bending machine
US5193452A (en) * 1989-09-11 1993-03-16 Willem Dieperink Folding press with deflection compensating means
US5347840A (en) * 1991-08-17 1994-09-20 L. Schuler Gmbh Press comprising a press table and a sliding table
US5930888A (en) * 1995-12-01 1999-08-03 Ralph C. Ball Device to hold, dispense and install slotted weights used with fishing line
US6401512B1 (en) 1998-09-09 2002-06-11 Amada Europe Press brake with active lower table
FR2782942A1 (en) * 1998-09-09 2000-03-10 Amada Europ Sa press brake is active lower apron
WO2000013813A1 (en) * 1998-09-09 2000-03-16 Amada Europe Press brake with active lower table
US20040103707A1 (en) * 2000-12-12 2004-06-03 Andreas Winters Internal high pressure forming device and method and corresponding tool system
US7013698B2 (en) * 2002-10-17 2006-03-21 Alberto Arduino Bending press with a substantially undeformable toolholder beam
US20040099038A1 (en) * 2002-10-17 2004-05-27 Alberto Arduino Bending press with a substantially undeformable toolholder beam
WO2013072859A1 (en) * 2011-11-15 2013-05-23 Adira, S.A. Beam for deformation compensation in press brakes
EP2682198A1 (en) * 2012-07-06 2014-01-08 Gasparini Industries S.r.l. Cambering device in bending presses
US20150273555A1 (en) * 2012-10-18 2015-10-01 Nivora Ip B.V. Spring Means for Device for Working Sheet-Like Material
US9440275B2 (en) * 2012-10-18 2016-09-13 Nivora Ip B.V. Spring means for device for working sheet-like material
USD807933S1 (en) * 2015-08-14 2018-01-16 Henri Emil Louis Maurice Zermatten Tool for a press brake

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