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
  • B21D9/00—Bending tubes using mandrels or the like
  • B21D9/14—Wrinkle-bending, i.e. bending by corrugating
• • 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
  • B21D7/00—Bending rods, profiles, or tubes
  • B21D7/14—Bending rods, profiles, or tubes combined with measuring of bends or lengths

Definitions

• the invention relates to a method and a device for determining the spatial geometry of a curved extruded profile, in particular a pipe, which is held in a feed and fixing unit in the region along a first straight central axis (A) of the extruded profile and by means of a bending device around a predeterminable bending angle is bent in such a way that on one side of a bent region of the extruded profile caused by the bend, the region of the first straight central axis (A) and on the opposite side a region with a second straight central axis (B).
• extruded profiles are bar-shaped elements which, due to the nature of the manufacture and material, have a minimum stiffness along their extension and which, for the purposes of spatial deformation, can be subjected to a plastic bending process by means of which a permanent plastic bending deformation in the sense of a remaining curvature arises.
• Pipes are found, for example, in the form of pipeline systems for the transmission or conduction of gaseous or liquid media and, depending on local conditions, have curvatures or pipe bends along their extension.
• Such tubes which mostly measure a few mm to cm in cross-section, are introduced for processing into corresponding bending devices in which the tube to be bent is fixed on one side and locally deformed by means of a bending head.
• Known bending devices in this regard are described, for example, in DE 4335 901 A1, DE 19530 805 A1 and CH 689 378 A5.
• Bending machines can basically be divided into two categories, namely bending machines with a stationary bending head, in which the pipe to be bent is fed to a stationary bending head, which usually consists of two bending jaws, via a feed and fixing unit and is plastically deformed accordingly by bringing the two bending jaws together.
• Bending machines of the other category provide a moving bending head, in which a bending head which carries out translatory and rotary movements is moved relative to a fixed tube and is locally pressed at a suitable point against the tube in order to produce a curvature.
• the tube is completely removed from the bending device in a manner known per se and checked accordingly as a loose individual piece.
• touching i.e. tactile systems
• non-contact measuring systems primarily based on optics
• Tactile measuring systems are so-called coordinate measuring machines or articulated measuring arms, by means of the curved pipe surface is scanned point-wise on a large number of surface areas, a number of three-dimensional coordinate points being obtained in relation to a reference coordinate system, from which a complete geometry of the bent pipe can be calculated by subsequent mathematical aprox optimization.
• non-contact methods provide for scanning the bent tube using triangular or linear triangulation methods or photogrammetry methods in order to also determine the tube geometry using mathematical evaluation methods.
• Methods for determining the three-dimensional tube geometry are also known, which operate with the aid of fork-shaped arrangements using optical light barriers, which are moved lengthwise to extend the bent tube and thereby capture 3-D surface points which, as already mentioned above, are used to determine a mathematical evaluation algorithm the three-dimensional spatial geometry.
• DE 43 30420 A1 describes a pipe bending machine with a bending head carried by a slide, which has a first bending roller stationary with a housing of the bending head and a second bending roller arranged on a bending arm.
• the axes of the bending rollers run parallel to each other and perpendicular to the axis of the pipe to be bent.
• two drive motors are provided, one of which serves to move the slide along a guide and thus to move the bending head along the tube, and a second drive motor serves to pivot the bending arm about the axis of the first bending roller.
• An angle encoder is provided in the gear train between the second drive motor and the bending head, by means of which the bending angle ( ⁇ ) of the bending arm can be detected.
• the respective position of the bending arm with bending roller is transmitted to a circuit by the angle encoder, the bending angle being determined by a target / actual value comparison.
• the circuit described in this document therefore only makes it possible to compare the actual value of the movement of the bending arm with a target value to be entered into the control.
• the resilience of the tube, which results after the tensioning device is released from the tube, cannot be taken into account with this device, however, since the bending angle is only determined when the tube is clamped.
• No. 5,992,210 describes a device for bending an endless tubular string.
• the device has a feed unit, in each case a fixing unit for the pipe section to be bent and the pipe section not to be bent, and a swivel arm through which the pipe section to be bent is brought into the desired shape. After the bending process, the fixing device, which is located on the swivel arm, is released and the shape produced is detected by sensors.
• the entire bent tube is to be regarded as a reject product.
• the curved pipes which extend up to several meters, have only a low intrinsic stability, so that they cannot be measured in their actual curved spatial shape without additional auxiliary templates to support the dead weight.
• the invention is based on the object of a method and a device for determining the spatial geometry of a curved extruded profile which is held in a feed and fixing unit in the region along a first straight central axis (A) of the extruded profile and by means of a bending device by a predefinable bending angle ⁇ such is bent so that on one side of an area of the extruded profile caused by the bend the area of the first straight central axis (A) and on the opposite side an area with a second Connect the straight central axis (B) in such a way that if a large number of bending processes are to be carried out in succession along the tube, each individual bending angle should be determined exactly.
• it is necessary to measure further parameters determining the spatial geometry of the bent pipe so that after the one-time bending process has taken place, a statement can be made as to whether the bending process has achieved the desired bending result.
• claim 18 is a device according to the invention for bending extruded profiles.
• an extruded profile for example a pipe
• a tube is used as the extruded profile, but the tube can also be replaced by other alternatives, e.g. by round bars made of solid material or other geometrically shaped extruded profiles, such as flat materials, U- or V-shaped extruded profiles, by just a few to call.
• a contactless or tactile measuring sensor is preferably used, the spatial position of which is known in relation to the bending device and / or to the feeding and fixing unit.
• the essential aspect of the method according to the invention is that the determination of the spatial position of the central axis (B) takes place after completion of the bending process, i.e. after the pipe has been released by the bending device, so that material-related springback effects are also included in the measuring process can, and while the tube remains fixed or held in the feed and fixing unit.
• the tube consequently remains in a fixed position defined by the feeding and fixing unit during the measurement. Only in this way is it possible that, after completion of the measuring process, the tube can be moved from the "frozen" measuring position to a subsequent bending position relative to the bending device in a controlled manner, so that a subsequent bending process can be carried out on the pipe with a fixed spatial reference to the previous bending process.
• the determined bending angle is compared with a predetermined target bending angle SO ⁇ . If it turns out that deviations occur that go beyond a likewise specified tolerance range, a signal is generated which is used for a number of further measures.
• Corrected bending parameters are determined for the necessary post-processing of a bend, with which the bending process is repeated in order to to improve the bending result.
• the corrected bending parameters can also be used as a basis for further bending processes along the extruded profile, especially since it can happen that the material properties change along the extruded profile, which can be taken into account in this way by the updated bending parameters
• the method according to the invention it is proposed, in addition to the detection of the bending angle, as described above, to also detect the feed lengths along the pipe between two successive bending processes in order to obtain precise knowledge of the mutual distance between two curved pipe regions.
• a suitable angle of rotation measuring device about which the tube is rotated along its central axis (A) during two bending positions.
• this information can be used to determine not only the bending angle ⁇ lying in the plane described by both central axes A and B, but also the angle by which the pipe is relative to the normal plane to the central axis A is bent.
• the actual spatial shape of the curved extruded profile with a desired spatial shape according to the bending plan can be viewed by looking at all the measured and stored measurement data be compared. This comparison is primarily used for product quality checking and quality assurance.
• a bending device which carries out the above bending process for bending an extruded profile with a feed and fixing unit, by means of which the extruded profile can be fed and fixed as straight yard goods, and with a bending device arranged downstream of the feed and fixing unit in the feed direction along a straight central axis (A) of the extruded profile , with a bending head consisting of at least two bending bodies, which, during the bending process, at least partially enclose the extruded profile to be bent locally and can be moved into an open position releasing the extruded profile, is characterized in that a measuring sensor with a fixed spatial reference for the supply and fixing unit and / or to the bending device is provided, which subsequently detects the spatial position of a straight central axis (B) of the extruded profile in the region directly on the bending device in the feed direction of the extruded profile.
• a storage and evaluation unit in which the measurement values of the measurement sensor can be stored and evaluated in such a way that an angle ⁇ , the so-called bending angle, can be determined, which is included by the central axes (A) and (B). In this way it can be ensured that Even after completion of the bending process, information about the actual spatial shape of the bent extruded profile can be obtained, which can be used for further evaluation.
• Fig. 1 shows a schematic representation of an inventive
• Figure 1 shows schematically a device for bending or bending a tube 1 and for detecting the spatial geometry of the pipe course bent by the bending process.
• the tube 1 which is available by the meter, passes via a feed unit 2, consisting of two roller rollers, into a fixing unit 3 designed as a counter-holder, through which the tube 1 is pushed along its straight central axis A.
• a bending device 4 consisting of an inner bending jaw 41 and outer bending jaw 42 is provided, which can be moved into an open position for the insertion of the tube 1.
• the bending jaws 41 and 42 are shown in the closed position.
• the bending process of the tube 1 with the aid of the bending device 4 takes place in such a way that the outer bending jaw 42 deforms the tube against the inner bending jaw 41 in a region 11 to be curved by means of a rotational movement (see arrow illustration).
• a straight pipe section 5 which is oriented along the central axis A prior to the bending process, is inclined from the original central axis A and has a straight central axis B after the bending.
• the angle ⁇ enclosed by the central axes A and B corresponds to the bending angle which must be determined exactly after the bending process has been completed.
• the bending angle is measured by determining the spatial position of the central axis B, which adjoins the currently curved pipe section 5.
• the determination of the central axis B which at the same time also corresponds to the cylinder axis of the tube in the region 5, is carried out with the aid of a non-contact sensor 6, which is fixedly attached to the outer bending jaw 42 and thus has a fixed spatial reference to the bending device 4.
• a non-contact sensor 6 which is fixedly attached to the outer bending jaw 42 and thus has a fixed spatial reference to the bending device 4.
• the sensor 6 is a laser sensor based on the triangulation technique, which has a camera unit 61 and two light sources 62 designed as line lasers. With the aid of optics (not shown), this light section sensor 6 projects one line per light source 62 onto the surface of the tube, which line is detected by the camera unit 61. With the aid of the light section sensor 6, 3-D points on the pipe surface are determined along the light lines, from which the cylinder center axis, the so-called center axis B, is determined by cylinder approximation. The spatial position of the central axis A can be assumed to be known, especially since it is defined by the feeding and fixing unit 2, 3 and the bending device 4.
• the bending angle ⁇ between the two axes A and B can be determined based on the spatial Cartesian coordinate system X-Y-Z.
• the senor 6 or an additional measuring unit is used to detect the external spatial shape of the extruded profile, for example to determine flattening of a pipe as an extruded profile.
• Such flattening can occur in the way of the bending process, which jeodch This must be avoided in a targeted manner, for example by correcting bending parameters during further bending processes or in the case of corresponding subsequent corrections.
• the course of the neutral fiber 7 within the tube 1, in particular in the region of the bends 5, in which the neutral fiber 7 shifts from the tube center in the direction of the inner radius, is taken into account in the determination of the length of the straight sections 5 in the form of parameters.
• the parameters are determined depending on the bending angle, pipe diameter, pipe material and pipe wall thickness.
• the device shown in Figure 1 for determining the geometric shape of pipes during the bending process in the machine enables an immediate quality assessment of the shape and shape of a bent pipe.
• bending angle errors occurring during the bending process are immediately detected.
• the cause of these errors is, in particular, springback of the bent tube after the bending process, which is caused, among other things, by fluctuations in material properties.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Bending Of Plates, Rods, And Pipes (AREA)
• Length Measuring Devices By Optical Means (AREA)
• Length Measuring Devices With Unspecified Measuring Means (AREA)
• Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)

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• 2001
  • 2001-06-27 DE DE10130937A patent/DE10130937C1/de not_active Expired - Fee Related
• 2002
  • 2002-06-27 EP EP02754778A patent/EP1401595B1/fr not_active Expired - Lifetime
  • 2002-06-27 WO PCT/EP2002/007121 patent/WO2003002280A1/fr not_active Application Discontinuation
  • 2002-06-27 AT AT02754778T patent/ATE304416T1/de not_active IP Right Cessation
  • 2002-06-27 DE DE50204272T patent/DE50204272D1/de not_active Expired - Lifetime
  • 2002-06-27 US US10/482,208 patent/US7489412B2/en not_active Expired - Fee Related

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