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
  • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
  • B21D5/02—Bending sheet metal along straight lines, e.g. to form simple curves on press brakes without making use of clamping means
  • B21D5/0272—Deflection compensating means
• • 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
  • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
  • B21D5/02—Bending sheet metal along straight lines, e.g. to form simple curves on press brakes without making use of clamping means

Definitions

• the present invention relates to a press brake for folding metal sheets of the type comprising an upper deck arranged above a lower deck, the latter being fixed in abutment at its ends while the upper deck is movable and actuated in a plane vertical by drive members also located at its two ends.
• the drive members provide the force necessary to bend the metal sheets or sheets and these cause the deformation of the two decks in the opposite direction.
• the longitudinal deformation curves of the decks are substantially symmetrical with respect to the plane of separation of the decks so that the maximum distance between the decks is located near the middle of the thrust points (drive members and fixed supports) and represents twice the maximum deformation of each deck.
• the maximum difference between the upper and lower aprons is an essential parameter of the precision and quality of the fold produced and in the case mentioned above, the two aprons being more apart in the middle than at the ends, the fold will be more open to the center only at said ends.
• Japanese utility model 2 558 928 which describes a press brake comprising a movable upper deck and a fixed lower deck formed by a plate of uniform thickness in which two symmetrically identical slots are made. relative to the median transverse plane of said lower deck.
• Each slot has an upper wall and a lower wall connected by a bottom as well as an opening situated at the level of the corresponding lateral edges of the plate.
• the plate thus comprises a lower part and an upper part situated respectively below and above the slots.
• the lower part of the plate is fixed to two flanges which also support the upper deck, while the upper part of the plate or more exactly its ends are free to move in a vertical plane.
• This Japanese utility model also indicates that the slots are each provided with a movable member whose position is adjustable manually or automatically, inside the slots.
• This movable member is directly in contact with the lower and upper walls of each slot and its movement makes it possible to virtually limit the depth of said slots and therefore to decrease as the movable member approaches the openings, the elasticity of the lower apron.
• the use of this type of press brake does not, unfortunately, allow perfect control of the parallelism of the deformation curvatures of the edges opposite the lower and upper decks.
• the pressure exerted on the free upper part of the lower deck is only a function of the force applied by the work of the drive members on the upper deck and therefore consequently by the sheet to be bent and nothing under these conditions makes it possible to act voluntarily on these pressures and therefore on the deformations of said upper part of the lower deck so that these are perfectly parallel to the deformations of the upper deck.
• the movable member when the movable member is located substantially at the bottom of the slot and the force applied by the work of the members is significant, the deformation curvature of the lower deck is then maximum and in this case the intrinsic elasticity of the upper part of the lower deck can be irreparably damaged.
• the object of the present invention is to overcome the above-mentioned technical problems in a satisfactory manner.
• a press brake for folding metal sheets of the type comprising an upper apron disposed above a lower apron, the lower apron being fixed in abutment at its ends while apron upper is movable and actuated in a vertical plane by drive members also located at its ends, the lower deck being constituted by a plate comprising a free upper part and a fixed lower part delimited by two slots symmetrically identical with respect to the transverse plane median of said lower apron, each slot comprising an upper wall and a lower wall connected by a bottom as well as an opening situated at the level of the corresponding lateral edges of the plate, characterized in that each slot is equipped with a displacement member connecting the free upper part and the fixed lower part of the lower apron to bring the upper wall of the slot closer to its lower wall, whereby the deformation curvature of the free upper part of said lower apron is modified.
• each displacement member comprises on the one hand a fixed part connected to the lower wall of the slot and on the other hand a movable part secured to the upper wall of the slot.
• each displacement member is located at the opening of the slots, so as to allow precise movement of the free ends of the upper walls of said slots.
• the press brake comprises a control assembly for independently controlling each displacement member as a function of the curvature which it is desired to give at each end of the free upper part of the lower deck.
• control assembly comprises:
• control assembly further comprises measurement means to obtain information on the effective curvature of the free upper part of the lower deck and the programmed curvature.
• the displacement member according to the invention makes it possible to control and securely adjust the curvature of deformation of the free upper part of the lower deck and this without risk of exceeding the elastic limit of said lower deck.
• FIG. 1 represents a schematic view of a press brake according to the invention with displacement members
• FIG. 2 represents a view in vertical section along the line II— II of FIG. 1, and
• FIG. 3 shows a schematic view of a control assembly for controlling the movement members.
• FIGS 1 and 2 show a press brake according to the invention.
• This press brake comprises an upper deck 1 and a lower deck 2 mounted in a frame formed by two flanges 9a and 9b joined together notably by a bracing beam (not shown).
• the upper aprons 1 and lower 2 are contained in the same vertical plane and the upper apron slides with respect to the flanges 9a and 9b using guide means 8a and 8b constituted for example by two hydraulic cylinders.
• the working edges of these two upper and lower aprons respectively carry a folding punch P and a corresponding matrix M.
• the bending angle of a metal sheet or sheet depends on the extent of the penetration of the punch P inside the die
• the lower apron 2 is constituted by a plate provided with two slots 3a and 3b symmetrically identical with respect to the median transverse plane of the lower apron represented in FIG. 1 by the section line II— II.
• Each slot 3a and 3b has an upper wall 31a and
• Each slot comprises, in addition, a bottom connecting the upper walls 31a and 31b and lower 32a and 32b at the central zone of the lower apron as well as an opening situated at the level of the corresponding lateral edges of said lower apron 2.
• the upper walls 31a and 31b are inclined at an angle relative to the lower walls 32a and 32b arranged horizontally. This angle can, of course, vary according to the displacement member fitted to said slots or else according to the range of press brake used.
• the lower apron 2 comprises an upper part 22 and a lower part 21 situated respectively above and below the two slots 3a and 3b.
• the lower part 21 of the lower deck 2 is fixed at its ends to the flanges 9a and 9b forming the frame of the press brake.
• the lower part 21 can be fixed by welding or any other means.
• the upper part 22 of the lower deck 2 is in turn only connected to the lower part 21 by means of the central zone located between the two bottoms of said slots 3a and 3b.
• each slot 3a and 3b is equipped with a displacement member 6a and 6b connecting the upper part 22 and the lower part 21 of the lower deck 2.
• the displacement members 6a and 6b are constituted by hydraulic cylinders.
• Each hydraulic cylinder 6a and 6b comprises a cylinder 4a and 4b fixed to the lower wall 32a and 32b of each slot and a piston rod 5a and 5b connected to the upper wall 31a and 31b by screwing or any other means.
• These hydraulic cylinders 6a and 6b are arranged at the opening of the slots so as to allow precise movement of the free ends of the upper walls 31a and 31b of said slots 3a and 3b, as will be described in detail later.
• These hydraulic cylinders work in retraction, which allows a bringing together of the upper walls 31a and 31b respectively towards the lower walls 32a and 32b whereby the deformation curvature of the free upper part 22 of said lower apron 2 is modified before any operation folding, i.e. before the vertical movement of the upper deck 1.
• control assembly 13 intended to independently control the stroke of each piston rod 5a and 5b of the hydraulic cylinders 6a and
• the control assembly 13 allows an operator to enter the desired deformation curvature for each of the halves of the free upper part of the lower apron 2, these two halves being defined by the median transverse plane of said lower apron 2.
• the assembly control unit 13 comprises a processing unit 11 constituted for example from a microprocessor. It also includes a keyboard 10 for introducing into the processing unit 11 the parameters of the deformation curvature to be produced for each half of the upper part 22 of the lower deck 2. The keyboard 10 could be replaced by any other acquisition means of data.
• the processing unit 11 is coupled to a program memory 12.
• the memory 12 contains in particular correspondence tables between the parameters of each deformation curvature which can be adjusted and the corresponding displacements which must be applied to the piston rods 5a and 5b of the hydraulic cylinders 6a and 6b.
• the operator will also enter by means of the keyboard 10 data in the control unit concerning the nature of the sheet to be folded, its thickness, its length as well as the characteristics of the fold to be obtained (fold angle, dimensions of tools ).
• the processing unit 11 is capable of sending displacement commands to each actuator 6a and 6b so that these bring the upper walls 31a and 31b respectively towards the lower walls 32a and 32b of the slots so that the deformation curvature of the upper part 22 of the lower deck 2 is perfectly parallel to the deformation curvature of the upper deck 1 during the bending phase of the sheet.
• the jacks 6a and 6b will be locked in position during the folding phase of said sheet. So that the processing unit sends displacement commands to the jacks 6a and 6b, provision may be made to connect the inputs A and B of the processing unit li to two servo valves 14a and 14b supplied by pumps (not represented). These valves 14a and 14b will receive control signals from the processing unit 11 and will directly supply the jacks 6a and 6b.
• control circuit 13 makes it possible to independently control each jack 6a and 6b, which makes it possible to produce eccentric folds on a sheet which would possibly be arranged only on one of the two halves of the lower deck 2, or else centered folds over the entire length of the lower deck 2, the jacks 6a and 6b then receiving in this case, the same movement instructions.
• control assembly 13 comprises measurement means 7a and 7b arranged at the openings of the two slots 3a and 3b. These measurement means have the function of measuring the distance between the free end of the upper part 22 and the end fixed of the lower part 21 of the lower apron 2, in order to control the deformation curvature of the lower apron 2.
• the processing unit then sends error correction instructions to the jacks 6a and 6b.
• control assembly can permanently send error correction instructions to the displacement members 6a and
• the invention is in no way limited to the embodiment described and shown which has been given only by way of example.
• the displacement members 6a and 6b can be moved manually or electrically or by any other means constituting a technical equivalent.
• each slot may be parallel to each other and in this case advantageously provision may be made to arrange the fixed part of the displacement member in a notch formed on the lower wall of each slot.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Bending Of Plates, Rods, And Pipes (AREA)
• Press Drives And Press Lines (AREA)
• Battery Electrode And Active Subsutance (AREA)
• Presses And Accessory Devices Thereof (AREA)
• Spinning Or Twisting Of Yarns (AREA)
• Medicines Containing Material From Animals Or Micro-Organisms (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=9530251

Family Applications (1)

Country Status (7)

Cited By (4)

Families Citing this family (12)

Family Cites Families (11)

• 1998
  • 1998-09-09 FR FR9811240A patent/FR2782942B1/fr not_active Expired - Fee Related
• 1999
  • 1999-09-08 WO PCT/FR1999/002131 patent/WO2000013813A1/fr active IP Right Grant
  • 1999-09-08 EP EP99941714A patent/EP1112130B1/de not_active Expired - Lifetime
  • 1999-09-08 US US09/763,626 patent/US6401512B1/en not_active Expired - Fee Related
  • 1999-09-08 JP JP2000568605A patent/JP4434493B2/ja not_active Expired - Fee Related
  • 1999-09-08 AT AT99941714T patent/ATE215854T1/de not_active IP Right Cessation
  • 1999-09-08 DE DE69901261T patent/DE69901261T2/de not_active Expired - Lifetime

Non-Patent Citations (1)

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