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
  • B21D5/01—Bending sheet metal along straight lines, e.g. to form simple curves between rams and anvils or abutments
  • B21D5/015—Bending sheet metal along straight lines, e.g. to form simple curves between rams and anvils or abutments for making tubes
• • 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
  • B21D19/00—Flanging or other edge treatment, e.g. of tubes
  • B21D19/08—Flanging or other edge treatment, e.g. of tubes by single or successive action of pressing tools, e.g. vice jaws

Definitions

• the present invention relates to an edge-bending press and in particular relates to an edge-bending press suitable for processing metal sheets for the production of longitudinally welded pipes.
• the present invention relates to an edge-bending press for imparting a curvature to the edges of the sheets.
• This operation is illustrated generally in Figures 1 to 3.
• This operation is completed by means of two presses with an open C-shaped frame.
• the two presses are situated opposite each other and positioned at a suitable distance so that each one operates on one of the two longitudinal edges of the sheet.
• This solution is described for example in the patent US 3,911,709. With this known solution it is possible to obtain, by displacing one press with respect to the other one, configurations suitable for the different widths of the sheets to be processed.
• the width of the sheet is in fact variable from a minimum of about 2 m to a maximum of about 4.5 m, depending on the different diameters of the pipe which is to be obtained.
• the edge- bending presses designed for the described function are able to generate a force in the direction of operation (referred to as "separation force” and regarded below as vertical) which is of the order of thousands of tonnes.
• This force is necessary in order to be able to bend sheets of considerable thickness, for example thicknesses which are of the order of some centimetres.
• the sheet reacts to the separation force applied by the press, with a complex system of reaction forces. With respect to external effects, these reaction forces may be regarded as a vertical resultant, a horizontal resultant and a moment .
• each of the two C- shaped presses is subject to a notable overturning moment.
• the overall system must take account of this moment, allowing each of the two presses to perform a limited rotational movement in order to comply partially with this moment.
• one task of the present invention is to provide an edge-bending press such that a closed system of reaction forces is obtained on the two edges of the sheet, resulting in a system of forces which is symmetrical and zero with respect to external effects.
• the abovementioned object and tasks are achieved by an edge-bending press in accordance with that claimed in Claim 1.
• FIG. 1 shows a schematic cross-sectional view of a generic edge-bending press during a first working step
• FIG. 2 shows a view of the press according to Figure 1 during a second working step
• FIG. 3 shows a view of the press according to Figure 1 during a third working step
• FIG. 4 shows a partially cross-sectioned front view of an edge-bending press according to the invention
• FIG. 7 shows a view, similar to that of Figure 4, of another edge-bending press according to the invention.
• FIG. 8 shows a partial view of the cross-section along the line VIII-VIII in Figure 7, where some parts have been removed for greater clarity.
• 10 denotes in its entirety an edge-bending press according to the invention, while 100 denotes the sheet being processed.
• the edge-bending press 10 according to the invention comprises an upper platen 12, a lower platen 14 and operating actuators 16.
• the operating actuators 16 are designed to cause a relative movement of the upper platen 12 and lower platen 14 towards and/or away from each other.
• the press 10 also comprises an upper die- holder assembly 22 which is connected to the upper platen 12 and a lower die-holder assembly 24 which is connected to the lower platen 14.
• Each die-holder assembly 22, 24 comprises a right-hand die-holder and a left-hand die-holder; thus there is an upper right-hand die-holder 222, an upper left-hand die-holder 224, a lower right-hand die-holder 242 and a lower left-hand die-holder 244.
• the press 10 according to the invention also comprises adjustment actuators 18 designed to cause a relative movement of the right-hand die-holders 222, 242 and the left-hand die-holders 224, 244 towards and/or away from each other.
• the press 10 according to the invention also comprises centring actuators 20 designed to impart a movement involving displacement of the die-holder assemblies 22, 24 along the platens 12, 14.
• the longitudinal direction is understood as being the horizontal direction for feeding the sheet 100 to the press 10;
• the transverse direction is understood as being the horizontal direction perpendicular to the ' longitudinal direction.
• top, upper, up, overlying and the like and the terms bottom, lower, low, underlying and the like refer to the press 10 correctly installed and in working order.
• the reference to right-hand and left-hand is based on a view of the press 10 which is similar to that in Figure 4. Obviously the right-hand and left-hand positions could be equally well reversed.
• the press 10 also comprises a frame 26 on which the platens and the actuators are mounted.
• the frame 26 rests on a base and comprises preferably an upper horizontal member 262 and a lower horizontal member 264.
• the two horizontal members are connected by a right-hand vertical member 266 and a left-hand vertical member 268.
• the upper platen 12 is fixed on the frame 26, while the lower platen 14 is movable as a result of the action of the operating actuators 16.
• the upper platen 12 is movable and the lower platen 14 is fixed.
• the operating actuators 16 comprise hydraulic actuators of the cylinder and piston type. The operating actuators 16 act in the vertical direction.
• the operating actuators 16 are positioned at the top of the upper platen 12 and act on the lower platen 14 by means of tie-rods 160.
• the operating actuators 16 comprise an auxiliary cylinder and piston unit (not shown in the Figures) and a main cylinder and piston unit 164.
• the two auxiliary and main units 164 are preferably arranged in a parallel configuration. The function and the interaction between the two cylinder and piston units, i.e. auxiliary unit and main unit 164, is explained in detail below.
• convex dies 226 are mounted on the upper die-holder assembly 22, while concave dies 246 are mounted on the lower die-holder assembly 24.
• concave dies are mounted on the upper die-holder assembly, while convex dies are mounted on the lower die-holder assembly.
• the dies 226, 246 are interchangeable so as to allow replacement of the worn dies, but in particular so as make it possible to achieve different radii of curvature for the edges of the sheets.
• the curvature to be imparted to the edges of the sheet 100 in fact depends on the diameter of the finished pipe to be obtained.
• the adjustment actuators 18 comprise hydraulic actuators of the cylinder and piston type.
• the adjustment actuators 18 comprise an upper adjustment actuator 182 and a lower adjustment actuator 184.
• the adjustment actuators 18 act in the transverse direction.
• the adjustment actuators 18 may be mechanical instead of hydraulic in nature.
• Mechanical actuators which are suitable for this purpose may be threaded-bar actuators or rack-and-pinion actuators.
• the upper adjustment actuator 182 is mounted on the upper platen 12, while the lower adjustment actuator 184 is mounted on the lower platen 14.
• the adjustment actuators 18 are mounted on the respective platens so as to be able to slide in the transverse direction relative thereto.
• the adjustment actuators 18 may, for example, be mounted by means of tracks, rails or the like.
• the upper right-hand die- holders 222 and the upper left-hand die-holders 224 are fixed to the upper adjustment actuator 182.
• the lower right-hand die-holder 242 and the lower left- hand die-holder 244 are fixed to the lower adjustment actuator 184.
• the upper right-hand die- holder 222 is rigidly fixed to the outer casing 182" of the cylinder, while the upper left-hand die-holder 224 is rigidly fixed to the end 182' of the piston rod.
• the centring actuators 20 comprise hydraulic actuators of the cylinder and piston type.
• the centring actuators 20 comprise an upper centring actuator 202 and a lower centring actuator 204.
• the centring actuators 20 act in the transverse direction.
• the centring actuators 20 may be mechanical instead of hydraulic in nature.
• Mechanical actuators which are suitable for this purpose are threaded-bar actuators or rack-and-pinion actuators.
• the upper centring actuator 202 is mounted on the upper platen 12, while the lower centring actuator 204 is mounted on the lower platen 14.
• the outer casing 202" of the cylinder of the upper centring actuator 202 is rigidly connected to the upper platen 12.
• the end 202' of the piston rod of the upper centring actuator 202 is connected to the upper adjustment actuator 182.
• the outer casing 204" of the cylinder of the lower centring actuator 204 is rigidly connected to the lower platen 14.
• the end 204' of the piston rod of the lower centring actuator 204 is connected to the lower adjustment actuator 184.
• the end 202' of the piston rod of the upper centring actuator 202 is connected to the upper adjustment actuator 182 by means of the upper left-hand die-holder 224.
• the end 204' of the piston rod of the lower centring actuator 204 is connected to the lower adjustment actuator 184 by means of the lower left-hand die-holder 224.
• the centring actuators may be adopted, provided that operation of the centring actuators is able to move the adjustment actuators and the die- holders fixed thereto.
• the upper platen 12 comprises a fixing plate 120 to which the outer casing 202" of the cylinder of the upper centring actuator 202 is rigidly fixed.
• the lower platen 14 comprises a fixing plate 140 to which the outer casing 204" of the cylinder of the lower centring actuator 204 is rigidly fixed.
• the centring actuators 20 comprise adjustable safety valves (not shown in the figures) .
• the press 10 also comprises means 28 for moving the sheet 100 and/or means 30 for clamping the sheet.
• the means 30 comprise (hydraulic or mechanical) actuators with respective abutments.
• the means 30 are able to exert on the sheet 100 a clamping force such as to keep the sheet itself in the correct position also in response to disturbances in the system of forces generated during operation of the press 10.
• This clamping force may be quantified as being a good 20% of the force which the press 10 requires in order to perform bending of the edges (or crimping) .
• the clamping means 30 are mounted in a manner known per se on straight guides so as to be able to slide in the transverse direction together with the die-holders.
• the clamping means 30 must in fact be able to act in the vicinity of the edges of sheets of various widths.
• the clamping means 30 are mounted, in a manner known per se, between the lower platen 14 and the upper platen 12 of the press 100. In this configuration, during the crimping action, the operating actuators 16 must also overcome the force exerted by the clamping means 30.
• the clamping means 30 are instead mounted on the frame 26.
• the clamping means 30 are mounted on the lower horizontal member 264 by means of straight guides so as to be able to slide in the transverse direction together with the die-holders.
• the clamping means 30 must in fact be able to act in the vicinity of the edges of sheets of various widths.
• the force exerted by the clamping means 30 does not influence the force of the operating actuators 16.
• the operating actuators 16 may be designed so as to develop a force about 20% less than that of the preceding solution. All other factors being equal, it can be noted how this solution achieves a significant reduction in the dimensions and operation of the operating actuators 16 and the associated power supply plant.
• the press 10 also comprises means for controlling the operating movements, for example for controlling the hydraulic and/or mechanical operating, adjustment and/or centring actuators.
• the control means may advantageously comprise some of the following components: a user interface designed to receive commands from a user; pressure sensors able to detect the internal pressure of the hydraulic actuators; load cells able to detect the force exerted at a given point; displacement sensors able to detect the relative position of given components; safety sensors; actuating devices able to cause the displacement of the various hydraulic actuators; a processing unit designed to collect the signals received from the user interface and from the various sensors and operate the actuating devices depending on a predefined logic.
• the press 10 comprises a plurality of stations which are arranged next to each other in the longitudinal direction.
• Each station corresponds to the description given above and comprises an upper platen 12, a lower platen 14, operating actuators 16, die-holder assemblies 22 and 24, adjustment actuators 18 and centring actuators 20.
• the movable platens of the plurality of stations are connected together in the longitudinal direction by a middle member mounted between the said platens and the die-holders.
• This middle member may help improve mechanical synchronization of the various stations.
• Figure 5. a shows a press 10 according to the invention in a configuration similar to that of Figure 4.
• the press 10 is able to operate on sheets of maximum width (in the specific example about 4.5 m) . It is assumed below, again by way of example, that it is required to reconfigure the press 10 so as to be able to operate on sheets of different width, for example minimum width (in the specific example about 1.9 m) .
• Figure 5.b shows a first temporary configuration of the press 10 where the adjustment actuators 182 and 184 caused a relative movement of the right-hand die- holders and left-hand die-holders towards each other.
• this temporary configuration is obtained by keeping immobile the ends 182' and 184' of the piston rods of the upper adjustment actuator 182 and lower adjustment actuator 184, and therefore by keeping immobile the left-hand die-holders 224 and 244.
• the relative approach movement is obtained by means of the movement of the outer casings 182" and 184" of the upper adjustment actuator 182 and lower adjustment actuator 184.
• This movement therefore involves the movement of the right-hand die-holders 222 and 242.
• Asymmetrical positioning of the die-holders relative to the centre of the press 10 is thus produced.
• the asymmetrical configuration obtained would result in an asymmetrical load on the platens and therefore on the operating actuators 16 during crimping. It is therefore required firstly to displace rigidly the upper die-holder assembly 22 and lower die-holder assembly 24 so as to reposition them in a symmetrical configuration relative to the centre of the press 10.
• This rigid displacement of the die-holder assemblies 22 and 24 is obtained by means of the upper centring actuator 202 and lower centring actuator 204, respectively.
• clamping means 30 it is preferable to operate the clamping means 30, if present, in a manner known per se and as schematically illustrated in Figure 2.
• the use of the clamping means 30 allows the sheet to be kept in position also in the case of small disturbances in the system of forces.
• the operating actuators 16 comprise an auxiliary cylinder and piston unit (not shown) and a main cylinder and piston unit 164.
• the auxiliary piston has a working area which is decidedly smaller than that of the main piston. Since the two units, i.e. auxiliary unit and main unit 164, are supplied by the same hydraulic plant, the auxiliary unit is able to provide a smaller force (the oil pressure acts on a smaller surface area) , while ensuring a faster movement (the oil flow must supply a smaller volume) .
• the main unit 164 is able to provide a greater force (the oil pressure acts on a larger surface area) , but with a slower movement (the oil flow must supply a larger volume) .
• the auxiliary unit is therefore useful during the stroke performed by the lower platen 14 from the position shown in Figure 5.c into the position where the dies start to come into contact with the sheet 100.
• This stroke in fact requires a minimum force since it must overcome only the weight force of the lower platen 14 and the internal resistance of the press 10, while there is no reaction to be overcome on the part of the sheet 100.
• the main unit 164 instead intervenes when the reaction forces of the sheet 100 start to be generated.
• the operating actuators 16 it is therefore possible to obtain crimping of the sheet 100, as shown in Figure 3 and Figure 5.d.
• the adjustment actuators 18 must be able to maintain the predefined distance between the dies also during crimping, i.e. in response to transverse forces equivalent to thousands of tonnes. This control over the relative position of the dies is achieved in a known manner by means of the hydraulic system of the adjustment actuators 18. In ideal conditions, therefore, the force which is transmitted onto the fixing plates 120 and 140 during crimping has a zero value .
• the safety valve when the threshold value is reached, the safety valve is designed to allow oil to flow out from inside the actuator towards the storage tank.
• the safety valves may be constructed with an extremely simple and therefore reliable design.
• a mechanical valve which can preferably be pre-loaded in a variable manner depending on the specific requirements. It is thus possible to limit in a very simple manner to a predefined value the forces which may be transmitted by the centring actuators 202 and 204 onto the respective fixing plates 120 and 140, for example in the case of a nonsymmetrical system of reaction forces on the part of the sheet 100.
• This operating logic may also be adopted in the case of an edge-bending press of the known type in which die- holder positioning double rams are fixed to the centre of the platens.
• the safety device must comprise a sensor for detecting the pressure inside each of the two chambers of the said double ram and a circuit which limits the difference between the two pressures to a predetermined value. When the threshold value is reached, the safety device is designed to block operation of the press. It should be noted therefore how this safety device required by the configuration of the prior art is in fact more complex and therefore necessarily less reliable and robust than the simple safety valve of the press according to the invention.
• the press 10 comprises means for operating simultaneously, during the crimping step, the centring actuators 20 and the adjustment actuators 18. In this way it is possible to impart to the dies a movement away from each other in the transverse direction during the approach movement in the vertical direction. This function of the edge-bending press is useful for limiting or preventing slipping of the sheet on the dies.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Bending Of Plates, Rods, And Pipes (AREA)
• Press Drives And Press Lines (AREA)
• Auxiliary Devices For And Details Of Packaging Control (AREA)
• Control And Other Processes For Unpacking Of Materials (AREA)
• Orthopedics, Nursing, And Contraception (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

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• 2008
  • 2008-11-11 IT ITMI2008A001994A patent/IT1391762B1/it active
• 2009
  • 2009-11-09 US US13/121,530 patent/US20110277531A1/en not_active Abandoned
  • 2009-11-09 JP JP2011535201A patent/JP5442748B2/ja not_active Expired - Fee Related
  • 2009-11-09 WO PCT/IB2009/054973 patent/WO2010055459A2/en active Application Filing
  • 2009-11-09 CA CA2735989A patent/CA2735989A1/en not_active Abandoned
  • 2009-11-09 EP EP09825831A patent/EP2346627A2/en not_active Withdrawn

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