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
  • B21D25/00—Working sheet metal of limited length by stretching, e.g. for straightening
  • B21D25/02—Working sheet metal of limited length by stretching, e.g. for straightening by pulling over a die
• • 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
  • B21D25/00—Working sheet metal of limited length by stretching, e.g. for straightening
  • B21D25/04—Clamping arrangements

Definitions

• the invention relates to a stretch bending machine for deforming workpieces, and to a method for deforming the work piece using the stretch bending machine.
• the object of the present invention was to overcome the disadvantages of the prior art and to provide a stretch-bending machine and a method for deforming workpieces, by means of which the workpiece can be deformed with high precision.
• a stretch-bending machine is designed for deforming workpieces.
• the stretch bender includes:
• a second clamping receptacle with a second clamping head for clamping a second side of the workpiece wherein the second clamping receptacle is arranged at a distance from the first clamping receptacle on the machine frame and wherein the two clamping heads are designed for applying a tensile force in the pulling direction on the workpiece;
• a printing device with a plunger for deforming the workpiece wherein the printing device between the first clamping receptacle and the second clamping receptacle is arranged on the machine frame, wherein the plunger is adapted for applying a compressive force in a direction transverse to the direction of compression direction.
• the two clamping receptacles are flexible with respect to the application of the pulling direction.
• An advantage of the design of the stretch bending machine according to the invention is that the tension receptacles can be flexibly adapted to the respective degree of deformation of the workpiece to be deformed.
• the two clamping receptacles each comprise an electric motor, in particular a servomotor, for adjusting the clamping head and are thus designed to apply a tensile force to the workpiece.
• the clamping heads Due to the electromotive drive of the clamping fixture, the clamping heads can be positioned with high accuracy.
• a high tensile force can be applied to the workpiece by the electric motor drive by means of the clamping heads, which is easily adjustable and metered.
• such a drive can be easily, inexpensively and compactly integrated into the stretch bending machine.
• the electric motor of the clamping receptacle in particular with the interposition of a reduction gear, with a set screw, in particular a ball screw is coupled, wherein the electric motor is accommodated on a motor mount and the clamping head mounted by means of a linear guide relative to the motor mount adjustable at this is, wherein the ball screw for introducing a linear adjustment and an adjusting force is formed in the chuck.
• a spindle drive in particular a ball screw for transmitting high forces is formed and thereby has the least possible clearance.
• the clamping head can be mounted by means of the linear guide in the horizontal direction displaceable on the motor mount.
• the plunger is arranged by means of an electric motor, in particular a servomotor, adjustable on the machine frame, wherein the electric motor is accommodated on a motor mount, which is coupled to the machine frame and the plunger adjustable by means of a linear guide relative to the motor mount on Machine frame is mounted, wherein an adjusting thread, in particular a ball screw, is designed for introducing a linear adjustment and an adjusting force in the plunger and is coupled to the electric motor of the printing device, in particular with the interposition of a reduction gear.
• an electric motor in particular a servomotor
• adjustable on the machine frame wherein the electric motor is accommodated on a motor mount, which is coupled to the machine frame and the plunger adjustable by means of a linear guide relative to the motor mount on Machine frame is mounted
• an adjusting thread in particular a ball screw
• the clamping receptacle has a base unit which is coupled to the machine frame and has a pivoting unit, which is mounted pivotably in the base unit with respect to a pivot axis, the electric motor together with the motor mount and also the clamping head in the pivoting unit are encompassed and are pivotable together relative to the basic unit of the clamping receptacle.
• the pivoting unit of the clamping receptacle is coupled to an actuator, in particular a hydraulic cylinder or a pneumatic cylinder, by means of which the pivoting unit is actively rotatable relative to the basic unit.
• an actuator in particular a hydraulic cylinder or a pneumatic cylinder
• the pivoting unit can be actively rotated by this measure and thus can be returned to the end position or receiving position after the completion of the bending process.
• the clamping head designed to receive workpieces which are designed as a hollow profile, wherein an inner clamping unit is formed, which serves for frictionally clamping an inner side of the workpieces and wherein an outer clamping unit is formed, which for non-positive clamping an outer side of the workpieces is used.
• the advantage here is that through the inner
• the inner clamping unit has a first clamping finger and a second clamping finger, which are provided with their outwardly directed abutment surface for abutment with an inner side of the workpiece and that a wedge element is arranged between the two clamping fingers, wherein axial displacement of the wedge element, by means of an adjusting means, the distance between the two contact surfaces of the clamping fingers is adjustable.
• the outer clamping unit has a first Klemmfin- ger and a second clamping finger, which are provided with their inwardly directed contact surface for abutment on an outer side of the workpiece and that outside the two clamping fingers each have a wedge element is arranged by axial displacement of the wedge elements, by means of an adjusting means, the distance between the two contact surfaces of the clamping fingers is adjustable.
• both the first clamping head and the second clamping head have a compression spring by means of which the workpiece can be arranged centrally between the two clamping heads before closing the clamping heads.
• the workpiece for receiving not exactly must be placed centrally in the stretch bending machine, but that when moving the two clamping heads the workpiece on one of the two clamping heads can first come to rest and then by further feed movement of the two clamping heads the workpiece by equal pressure distribution in the compression springs of the two clamping heads is centered.
• a first support support is formed, on which the undeformed workpiece can be placed, wherein the first support support is displaceable in the vertical direction and that the machine frame a second support support is formed, at which the deformed Workpiece can be placed, wherein the second support support is displaceable in the vertical direction.
• the plunger has an upper plunger part and a lower plunger part, wherein the two plunger parts form a Einlegeut with a groove base and two mutually facing groove walls, which are each formed on a pressure stamp part, and wherein the workpiece in the Einlagenut receivable is and wherein the two pressure stamp parts are adjustable by means of an adjusting means in the distance relative to each other, so that the two groove walls are movable toward each other.
• the advantage here is that by means of the two relatively movable plunger parts the deformed profile can be crushed after the completion of the forming process, so that any bulges can be pushed out of the profile.
• the two clamping receivers have a coarse adjustment by means of which the distance between the clamping receivers is roughly adjustable to the length of the workpiece.
• the advantage here is that the stretch bending machine can be used for different lengths of workpieces by this measure.
• the clamping head of the clamping receptacle is adjustable between 50 mm and 1000 mm, in particular between 100 mm and 500 mm, preferably between 150 mm and 250 mm, relative to the motor mount.
• the advantage here is that The clamping head can be adjusted in a sufficiently large area and can be built as small as possible.
• the pressure stamp of the printing device is adjustable between 50 mm and 2,000 mm, in particular between 100 mm and 1,000 mm, preferably between 200 mm and 300 mm, relative to the motor mount.
• the advantage here is that the plunger can be adjusted in a sufficiently large area and can be built as small as possible.
• a method is provided for deforming a workpiece using a stretch-bending machine as described above. The method comprises the following method steps:
• An advantage of the method according to the invention is that the workpiece can be produced with high accuracy and also the forming parameters can be accurately maintained during the deformation process of the workpiece.
• the applied by the two clamping heads on the workpiece tensile force is chosen such that the workpiece between 5% and 100%, in particular between 20% and 95%, preferably between 70% and 80% of the yield strength of the workpiece is claimed.
• the advantage here is that a tensile force in the specified range of the yield strength of the workpiece causes the workpiece can be easily deformed and after the deformation process, the internal stresses in the workpiece can be minimized.
• the necessary tensile force is calculated by depositing the workpiece geometry and the strength properties of the workpiece.
• the advantage here is that by this measure the necessary tensile force can be calculated and thus can have an exact value.
• the actual tensile force applied to the workpiece is determined by measuring the motor current and thus determining the torque of the electric motors of the clamping receptacle.
• the advantage here is that by this measure, the actually applied tensile force can be determined easily and sufficiently accurately.
• external measuring sensors can be provided for determining the actual tensile force applied to the workpiece.
• the process of the two clamping heads takes place synchronously during the deformation process, wherein the center of the workpiece is held in the center of the plunger by active distance control.
• the advantage here is that during the deformation process, the center of the workpiece is held in the center of the plunger and thus a uniform deformation of the workpiece can be achieved.
• the pivot unit of the clamping receptacle is freely pivotable relative to the base unit of the clamping receptacle and is pivoted from the workpiece.
• the advantage here is that a pure tensile force is exerted on the workpiece by this measure, the clamping head and in this no bending moment is initiated.
• the pivoting unit of the clamping receptacle is pivoted back into a receiving position by means of the actuator of the clamping receptacle.
• the first support pad is moved in the vertical direction upwards and after clamping the workpiece in the clamping heads, the first support pad is moved down.
• the advantage here is that the workpiece can be easily inserted into the stretch bending machine by this measure.
• the second support support is displaced in the vertical direction upwards and serves to receive the workpiece. The advantage here is that when you open the clamping heads, the workpiece can be stored directly in the stretch bending machine.
• the upper pressure stamp part and the lower pressure stamp part during the deformation process in a mutually moved to clamping position be held and distanced from each other after the completion of the deformation process to release the workpiece.
• linear guides described in this document are formed in the illustrated embodiments in the form of recirculating ball bearings. However, it is also conceivable that the linear guides, for example in the form of positive sliding guides, such as dovetail guides are formed.
• spindle drives described in this document are designed in the illustrated embodiments in the form of ball screws. However, it is also conceivable that the spindle drives are designed, for example, as normal adjusting threads, such as trapezoidal threads.
• the electric motors described in this document are preferably designed in the form of servomotors. However, all other types of electric motors can be used which have a corresponding control.
• the forces occurring in the individual adjusting units of the clamping receptacles and printing device or electric motors due to the deformation of the workpiece can be detected for example by monitoring the motor current and thus the motor torque of the individual electric motors.
• force sensors or torque sensors detect the forces occurring directly.
• the electric motors can have internal position sensors by means of which the angle of rotation of the electric motor can be recalculated to the position of the components to be driven.
• the position of the components to be driven is detected directly by means of distance measuring sensors.
• the electric motors are coupled to a transmission.
• the clamping heads are formed rotatable with respect to a horizontal axis. This can be achieved that in the workpiece in addition to the bend by the plunger and a twist can be generated.
• the clamping heads can be driven by means of a rotary drive and the rotation can be actively set.
• the plunger has a variable width. This can be achieved, for example, by making the plunger split with respect to its width and by allowing the two side halves of the plunger to be displaced relative to one another. As a result, the bending position on the workpiece can be varied or different embodiments of the workpiece can thereby be produced.
• the inner clamping unit is designed for sealing the hollow profile and that by means of the stretch bending machine, a medium can be introduced into the hollow profile, for example, to be able to apply overpressure in the hollow profile.
• the medium may be, for example, a gas or a liquid, such as hydraulic oil. By this measure, it can be achieved that during the deformation process any dent resulting in the workpiece can be avoided.
• the medium may be preheated or cooled in order to apply a certain temperature in the workpiece can.
• local heat or cold can be applied to the workpiece by means of a heating or cooling device arranged on the stretch bending machine.
• a heating or cooling device arranged on the stretch bending machine.
• This can be realized, for example, by a gas burner which is directed onto the workpiece in the region of the bending point of the workpiece.
• a heating or cooling device is formed in the plunger.
• the heating or cooling device may for example also be designed in the form of a coil for induction heating.
• the heating or cooling device can locally influence the microstructure in the workpiece. This may be necessary in particular in the area of the deformation point.
• a detection means in particular an optical detection means, such as a camera or a laser for position and position detection of the Workpiece is provided.
• This position detection enables the workpiece to be received in the correct position in the clamping heads of the stretch bending machine.
• a core is inserted into the cavity of a workpiece designed in particular as a hollow profile.
• the advantage here is that the workpiece is supported from the inside when using the core, which is inserted into the cavity. Thus, deformations of the wall thickness of the workpiece are obstructed.
• Fig. 1 is a perspective view of a first embodiment of a stretch bending machine
• Fig. 2 is another perspective view of the first embodiment of a
• Fig. 3 is a perspective view of an embodiment of a plunger of
• FIG. 4 shows a perspective view of an exemplary embodiment of a clamping receptacle of the stretch-bending machine
• FIG. 5 shows a further perspective view of the embodiment of the clamping receptacle of the stretch bending machine
• FIG. 6 shows a perspective view of an exemplary embodiment of a pivoting unit of the clamping receptacle of the stretch bending machine
• 7 is a sectional view of the clamping head according to the section line VII-VII in Fig. 6 .;
• Fig. 8 is a schematic representation of a first embodiment of a core for
• Fig. 9 is a schematic representation of a second embodiment of a core for supporting the workpiece.
• Figures 1 and 2 each show a perspective view from different angles of an embodiment of a stretch bending machine 1 for deforming workpieces 2, wherein the same reference numerals or component names are used for the same parts. The following description is made based on a synopsis of FIGS. 1 and 2.
• the stretch-bending machine 1 comprises a machine frame 3 on which a first clamping receptacle 4 with a first clamping head 5 and a second clamping receptacle 6 with a second clamping head 7 are arranged.
• the first clamping head 5 serves to receive and tension a first side 8 of the workpiece 2
• the second clamping head 7 serves to receive and tension a second side 9 of the workpiece 2.
• the clamping receivers 4, 6 are arranged at a distance 10 to each other, wherein the distance 10 corresponds approximately to a length of the workpiece 2.
• workpieces 2 are deformed on the stretch bending machine 1 according to the invention, which have an elongated extension and are designed, for example, in the form of bars, flat iron, tubes, hollow profiles and the like.
• the workpiece 2 is designed in the form of a hollow profile, which therefore has a Inner side 11 and an outer side 12 which define a wall thickness of the hollow profile.
• the first chuck 5 and the second chuck 7 not only serve to clamp and hold the workpiece 2, but are also displaceable in a pulling direction 13, whereby a tensile stress on the workpiece 2 can be applied.
• the pulling direction 13 is parallel to the longitudinal direction of the workpiece. 2
• the first clamping head 5 and the second clamping head 7 can be coupled in the clamping receptacles 4, 6, so that for differently shaped workpieces 2 differently shaped clamping heads 5, 7 in the clamping receptacles 4, 6 can be added.
• a printing device 14 is provided with a plunger 15, which is also arranged on the machine frame 3.
• first tension receptacle 4, the second tension receptacle 6 and the pressure device 14 are mounted directly on an indoor floor and thus the machine frame 3 can be omitted and replaced by the hall floor or other recording.
• the pulling direction 13 is parallel to the longitudinal direction of the workpiece. 2
• the plunger 15 is displaceable in a direction transverse to the pulling direction 13 printing direction 16.
• the individual components in particular the first clamping receptacle, the second clamping receptacle 6 and the printing device 14 are arranged on the stretch bending machine 1, that both the pulling direction 13 and the printing direction 16 lie in a horizontal plane and at right angles are arranged on top of each other.
• By adjusting the plunger 15 in the printing direction 16 and press on the workpiece 2 this can be deformed in the stretch-bending machine 1 under simultaneous tensile load.
• the workpiece 2 is shown both in the undeformed starting position, in which it is aligned straight, as well as in its curved shape after the completion of the bending process.
• a coarse adjustment 17 is formed between the clamping receptacles 4, 6 and the machine frame 3.
• the coarse adjustment 17 can be designed in the form of a row of holes which is arranged in the machine frame 3 and corresponds with corresponding counter-holes in the clamping receiver 4, 6.
• Tension holder 4, 6 and machine frame 3 are selected, the distance 10 between the clamping receivers 4, 6 can be varied. It is preferably provided that the tension receptacles 4, 6 are arranged at an equal distance from the center 18 of the plunger 15. It can thereby be achieved that the center 19 of the workpiece 2, respectively, the longitudinal center of the workpiece 2, can be brought into coincidence with the center 18 of the plunger 15.
• the pressure stamp 15 of the printing device 14 is preferably coupled to a linear guide 20, by means of which it is arranged so as to be displaceable in the printing direction 16 on the machine frame 3.
• the linear guide 20 is formed in the form of a recirculating ball guide, wherein a guide rail 21 may be provided, which is fixed to the machine frame 3 and which cooperates with a guide carriage 22.
• a guide rail 21 may be provided, which is fixed to the machine frame 3 and which cooperates with a guide carriage 22.
• two of the guide rails 21 are formed, which are arranged at a distance from each other on the machine frame 3 and that a pressure stamp receptacle 23 is formed on which per guide rail 21, two guide carriages 22 are attached. Overall, therefore, four guide slide 22 may be attached to the plunger seat 23.
• the pressure stamp 15 may be arranged to be coupled to the pressure stamp receptacle 23 so that different pressure stamps 15 can be used for workpieces of various shapes. Furthermore, it can be provided that the pressure stamp receptacle 23 is coupled to an adjusting means 24, whereby the plunger 15 is displaceable between a retracted rest position and an advanced forming position. If the pressure piston 15 is in the retracted rest position, a straight and undeformed workpiece 2 can be inserted between the first tension receptacle 4 and the second tension receptacle 6.
• the adjusting means 24 of the printing device 14 is realized in the form of a ball screw drive 30.
• a recirculating ball nut 31 is connected to the plunger seat 23 and that a ball screw 32 is mounted in a motor mount 33 of the printing device 14.
• the motor mount 33 of the printing device 14 is fixedly coupled to the machine frame 3.
• an electric motor 34 is provided for driving the ball screw 32, which may be selectively coupled to a reduction gear 35.
• the electric motor 34 is preferably also fastened or arranged on the motor mount 33.
• a first support pad 25 is formed, in which the workpiece to be machined 2 can be inserted and held.
• the first support pad 25 by means of an adjusting means 26 in the vertical direction 27 is displaceable.
• a second support pad 28 may be provided which serves to receive the workpiece 2 in the deformed state.
• the second support support 28 can also be adjusted by means of an adjusting means 29 in the vertical direction 27 between a retracted position and a raised support position.
• Both the first support pad 25 and the second support pad 28 may have a plurality of individual support elements, which are arranged at a distance from each other.
• Fig. 3 shows a perspective view of the plunger 15 with the plunger seat 23, wherein in turn the same reference numerals or component names are used as in the previous figures 1 and 2 for the same parts. In order to avoid unnecessary repetition, reference is made to the detailed description in the preceding Figures 1 and 2 or reference.
• the guide carriages 22, which are arranged on the plunger seat 23, are clearly visible.
• the pressure ram 15 can comprise an upper pressure ram portion 36 and a lower pressure ram portion 37.
• the plunger parts 36, 37 can form a deposit groove 38 in which the workpiece 2 can be received.
• Such a Einlagenut 38 may be formed, for example, in a one-piece plunger 15.
• the insert groove 38 has a groove bottom 39, which is bounded by a groove wall 40 of the upper plunger 36 and by a groove wall 41 of the lower plunger 37.
• the upper pressure piston 36 and the lower pressure piston 37 are displaceable relative to one another, so that a distance 42 of the two pressure-piston parts 36, 37 relative to one another in a predefined adjustment range is adjustable.
• the distance 42 is preferably indicated as a normal distance between the groove wall 40 of the upper plunger 36 and groove wall 41 of the lower plunger 37. In other words, by adjusting the two pressure stamp parts 36, 37, the distance between the two is expressed
• an adjusting means 43 is formed, which serves for adjusting the two pressure-stamping parts 36, 37 to each other.
• the adjusting means 43 may be formed for example in the form of a hydraulic cylinder of a pneumatic cylinder or other unit, such as electric motor with spindle drive or electric motor with eccentric shaft.
• two adjusting means 43 are provided, which are arranged at a distance from each other and serve to adjust the pressure stamp parts 36, 37.
• the execution of two adjusting means 43 has the advantage that, on the one hand, the possible application pressure force can be increased and, on the other hand, the pressure force can be symmetrically introduced into the groove walls 40, 41.
• the two pressure stamp parts 36, 37 For adjusting the two pressure stamp parts 36, 37 to one another, it can be provided that either the upper pressure stamp part 36 or the lower pressure stamp part 37 are coupled in a fixed position to the pressure stamp receptacle 23 and the other pressure stamp part 36, 37 is movable relative to the rigidly coupled pressure stamp part.
• the pressure-stamp parts 36, 37 are coupled to one another via a mechanism, wherein both pressure-stamp parts are moved toward and away from one another synchronously. It can thereby be achieved that the two groove walls 40, 41 are equally delivered to the workpiece 2.
• the groove walls 40, 41 may serve during the deformation process to avoid buckling in the workpiece or may be provided that any bulges resulting in the workpiece are expressed by moving the groove walls 40, 41 together.
• the plunger 36 may be divided into left and right plunger portions so that a width 86 of the plunger 36 is variably adjustable.
• a detection means 87 for detecting the workpiece is formed before and / or during and / or after the forming process.
• first tension receptacle 4 The individual components of the first tension receptacle 4 will be described with reference to a combination of Figures 1, 2, 4 and 5.
• first tension receptacle 4 and the second tension receptacle 6 are of the same design, with the second tension receptacle 6 being only a mirrored embodiment of the first tension receptacle 4.
• FIGS. 4 and 5 Only the first tension receptacle 4 will be described in FIGS. 4 and 5. It is clear to the person skilled in the art how the individual components of the first tension receptacle 4 are to be transferred to the second tension receptacle 6 in mirrored form. As can be seen from FIGS.
• the tension receptacle 4, 6 has a base unit 44, which is preferably rigidly coupled to the machine frame 3 via fastening means.
• the base unit 44 may be made in one piece, for example in the form of a welded component with a plurality of components welded together.
• the individual components of the basic unit 44 can also be connected to one another by means of fastening means.
• the base unit 44 is formed in one piece in the form of a casting.
• a pivot unit 45 can be accommodated, which can be pivotable relative to the base unit 44 with respect to a pivot axis 46.
• the pivot axis 46 is preferably aligned vertically.
• the pivoting unit 45 of the clamping receptacle 4, 6 is received or mounted on an upper side 47 of the basic unit 44 and on an underside 48 of the basic unit 44.
• a pivot bearing 49 is formed on the upper side 47 or on the lower side 48 of the basic unit 44.
• bolts are arranged both on the upper side 47 and on the underside 48 of the base unit 44 and the pivot bearing 49 is formed on the pivoting unit 45.
• the pivot bearing 49 for pivotally receiving the pivot unit 45 relative to
• Basic unit 44 can be realized by means of ball bearings or about by means of plain bearings.
• the pivoting unit 45 is coupled to an actuator 50, by means of which the pivoting unit 45 is actively pivotable relative to the base unit 44.
• the Akturator 50 may be formed for example in the form of a hydraulic or pneumatic cylinder, which is coupled by means of a lever 51 with the pivot unit 45 and thus can serve to initiate a rotational movement in the pivot unit 45.
• the actuator 50 is formed, for example, by an electric motor, which serves directly or indirectly to initiate the rotational movement into the pivoting unit 45.
• the base of the pivoting unit 45 is formed by a motor mount 52. All components installed on the swivel unit 45 can be attached to the motor mount 52.
• the motor mount 52 is pivotally mounted on the base unit 44 of the clamping receptacle 4, 6.
• the motor mount 52 may also be formed in one piece or in one piece in various embodiments.
• a linear guide 53 may be formed by means of which the clamping head 5, 7 is received linearly displaceable in the motor mount 52.
• two guide rails 54 can be arranged on the motor mount 52, with which two guide slides 55 interact, which are arranged on the clamping head 5, 7.
• an adjusting means 56 is provided by means of which the clamping head 5, 7 is active relative to the motor mount 52 linearly displaceable.
• the adjusting means 56 may for example a Include spindle drive.
• a ball screw 57 is formed, which serves for adjusting the clamping head 5, 7.
• the ball screw 57 may include a ball nut 58 which is rigidly connected to the chuck 5, 7.
• a ball screw 59 can be provided, which cooperates with the ball nut 58.
• the ball screw 59 may be mounted in a spindle bearing 60 which is rigidly coupled to the motor bracket 52. Furthermore, it can be provided that an electric motor 61, 62 serves to drive the ball screw 59. The electric motor 61, 62 may be coupled to the ball screw 59 via a reduction gear 63.
• FIG. 6 shows a perspective view of a variant embodiment of the pivoting unit 45 without depiction of the basic unit 44.
• the adjusting means 56 in particular the electric motor 61, 62 and the ball screw drive 57 for adjusting the clamping head 5, 7, are also shown in FIG not shown.
• an upper axle journal 64 and a lower axle journal 65 to be accommodated on the motor mount 52, which interact with the pivot bearing 49 arranged in the basic unit 44.
• the upper journal 64 may preferably be configured to accommodate the lever 51 with which the actuator 50 is coupled.
• the two stub axles 64, 65 can preferably be coupled to the engine mount 52 by means of fastening means.
• FIG. 6 also shows that the clamping head 5, 7 can have an inner clamping unit 66, which serves for clamping the inner side 11 of the workpiece 2. Furthermore, the clamping head 5, 7 may have an outer clamping unit 67, which serves for clamping the outer side 12 of the workpiece 2.
• a compression spring 68 can be provided, which is shown symbolically in FIG. 6 and is arranged in the clamping head 5, 7, wherein the compression spring 68 acts in the pulling direction 13 and serves to center the workpiece 2.
• 7 shows a sectional view of the clamping head 5, 7 according to the section line VII-VII in FIG. 6.
• the inner clamping unit 66 has a first clamping finger 69 and a second clamping finger 70.
• the first clamping finger 69 has an abutment surface 71, which is directed outwards.
• the second clamping finger 70 has an abutment surface 72, which is also directed outwards.
• Clamping fingers 69, 70 are used for frictional connection or for frictional recording with the inside 11 of the workpiece 2. Between the two clamping fingers 69, 70, a wedge element 73 is arranged, which in the adjustment direction 74 with respect to the clamping fingers 69, 70 is adjustable.
• a distance 75 of the contact surfaces 71, 72 of the two clamping fingers 69, 70 of the inner clamping unit 66 by means of an adjusting means 76 is adjustable.
• the adjusting means 76 may be formed for example in the form of a hydraulic cylinder or a pneumatic cylinder.
• An enlargement of the distance 75 can be achieved in that the wedge element 73 is pulled in a direction away from the workpiece 2 direction. A reduction of the distance 75 can be achieved by the wedge member 73 is pushed out.
• the spring stiffness of the clamping fingers 69, 70 is used here in order to move the clamping fingers 69, 70 toward one another when the wedge element 73 is pushed out.
• the outer clamping unit 67 may also include a first clamping finger 77 and a second clamping finger 78.
• the two clamping fingers 77, 78 have contact surfaces 79, 78, which are trimmed to each other and serve to clamp the outer side 12 of the workpiece 2.
• a distance of the two contact surfaces 79, 80 may be adjustable by means of an adjusting means 82.
• Analogous to the inner clamping unit 66 can be provided that outside of the two clamping fingers 77, 78 of the outer clamping unit 67, a wedge element 83 or in this case two wedge elements 83 are arranged, which can adjust the distance 81 of the contact surfaces 79, 80 of the outer clamping unit 67 by displacement in the adjustment direction 77 via corresponding wedge surfaces.
• the wedge elements 83 of the outer clamping unit 67 are coupled to the adjusting means 82 of the outer clamping unit 67.
• a spring element 84 can be provided, which presses apart the two clamping fingers 77, 78 of the outer clamping unit 67 and thus holds in its open position or serves to return the two clamping fingers 77, 78 during opening.
• the wedge surfaces between the wedge elements 83 and the clamping fingers 77, 78 may be formed such that in a slide before the wedge elements 83 in the direction of workpiece 2, the clamping fingers 77, 78 of the outer clamping unit 67 are moved towards each other and thus the workpiece 2 can be clamped , Upon retraction of the wedge elements 83, the clamping fingers 77, 78 can move apart again due to the force exerted by the spring element 84.
• a stop 85 which serves as a depth stop for the workpiece 2, can be formed on the inner clamping unit 66 or on the outer clamping unit 67.
• Both the contact surfaces 71, 72 of the inner clamping unit 66 and the contact surfaces 79, 80 of the outer clamping unit 67 may have a micro-toothing or otherwise to increase the friction and thus to increase the clamping force. Furthermore, it can be provided that at the individual sliding surfaces of the wedge elements 73, 83rd
• Lubricating grooves are formed, which serve to supply the sliding surfaces with lubricant to minimize wear. Accordingly, a plurality of grease nipples may be provided in the inner clamping unit 66 and in the outer clamping unit 67. Based on a synopsis of FIGS. 1 to 7, the sequence for forming the workpiece 2 by means of the stretch-bending machine 1 will be explained in the following description part.
• the workpiece 2 which is straight and undeformed, is inserted into the stretch bending machine 1. It can be provided that the first support pad 25 is displaced upwards and thus serves to receive the workpiece 2.
• the clamping heads 5, 7 in the pulling direction 13 can be symmetrically moved toward each other in order to introduce the workpiece 2 in the chuck 5, 7 can.
• compression spring 68 can be achieved that a not 100% centrally placed workpiece 2 is centered when moving the clamping heads 5, 7 and thus the center 19 of the workpiece 2 is aligned with the center 18 of the plunger 15 ,
• the first support pad 25 are moved downwards and thus be brought out of engagement to allow free deformation of the workpiece 2 by the plunger 15. Subsequently or parallel to the previous step, the two clamping heads 5, 7 in the pulling direction 13 can be moved symmetrically away from each other and thereby a tensile force is applied to the workpiece 2.
• the plunger 15 can be moved in the printing direction 16 on the workpiece 2 and deform it. During this deformation process shortens due to the deformation of the workpiece 2 whose overall length. Therefore, it is necessary that the clamping heads 5, 7 yield in the direction of the center 18 of the plunger 15 in order to maintain a certain tensile force can. In particular, it can be provided that the clamping heads 5, 7 are moved such that the center 19 of the workpiece 2 during the bending operation in the center 18 of the
• the workpiece 2 can be received in the insert groove 38 of the plunger 15. It can be provided that the groove walls 40 and 41 serve to stabilize the workpiece 2 or prevent buckling on the workpiece 2. As already described, it is possible that the groove walls 40, 41 are held at a predetermined distance 42 to each other during the entire forming process or that only after the completion of the forming process, the distance 42 of the two groove walls 40, 41 is reduced to each other and thereby the workpiece 2 is pressed into shape. Subsequently, the two groove walls 40, 41 are removed from each other, and thus the distance 42 is increased, whereby the workpiece 2 is released.
• the second support support 28, which serves to receive the finished formed workpiece can be moved upwards.
• clamping heads 5, 7 can be moved away from the workpiece 2, so that they come out of engagement of the workpiece 2.
• the workpiece 2 thus rests on the second support support 28 and can be removed from the stretch-bending machine 1.
• the second support support 28 can subsequently be moved downwards and the first support support 25 can be moved upwards to receive the new workpiece 2.
• the plunger 15 are moved to its original position.
• the clamping heads 5, 7 can be moved back by means of the actuator 50 in its initial position.
• FIG. 8 shows a schematic representation of a first exemplary embodiment of a core 89.
• the core 89 has a plurality of core segments 90, which are coupled to one another by means of a connection 91. Due to the segmentation of the core 89, it is flexible in its longitudinal extent and can adapt to the bending of the workpiece 2.
• the connection 91 of the individual core segments 90 can be realized for example by means of a leaf spring. Alternatively, it can also be provided that the individual core segments 90 are coupled together by ropes.
• the core 89 is inserted before the bending process in the formed as a hollow profile workpiece 2. During the bending process, the core 89 then serves to ensure that the cross-section of the workpiece 2 is somewhat preserved and does not dent or buckle. After completion of the bending process, the core 89 can be pulled out of the workpiece 2 again.
• FIG. 9 shows another embodiment of a core 89.
• the core 89 is used, for example, for bending open profiles, such as a C-profile.
• the core 89 has corresponding recesses into which the leg or legs of the workpiece 2 are introduced. During the bending process, the legs of the workpiece 2 are guided and can therefore be protected against buckling.
• the embodiments show possible embodiments, it being noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but also various combinations of the individual embodiments are mutually possible and this variation possibility due to the teaching of technical action by representational invention in Can the expert working in this technical field. The scope of protection is determined by the claims. However, the description and drawings are to be considered to interpret the claims. Individual features or combinations of features from the illustrated and described different embodiments may represent for themselves inventive solutions. The task underlying the independent inventive solutions can be taken from the description.
• Machine frame 31 Recirculating ball nut Pressure preload clamping fixture
• first clamping head 32 ball screw Druckvorrichzweite Spannfact tung

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Bending Of Plates, Rods, And Pipes (AREA)

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• 2016
  • 2016-07-07 AT ATA50606/2016A patent/AT518648B1/de active
• 2017
  • 2017-07-07 WO PCT/AT2017/060169 patent/WO2018006113A1/de active Search and Examination
  • 2017-07-07 EP EP17757664.2A patent/EP3481565B1/de active Active
  • 2017-07-07 DE DE202017007152.5U patent/DE202017007152U1/de active Active
  • 2017-07-07 CN CN201780054210.0A patent/CN109661282B/zh active Active
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