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
  • B21D7/00—Bending rods, profiles, or tubes
  • B21D7/14—Bending rods, profiles, or tubes combined with measuring of bends or lengths

Definitions

• This invention relates to a pipe or tube bending machine.
• a pipe bending machine comprising a bending head for engaging a pipe and drive means for displacing the bend ⁇ ing head so as to bend the pipe through an angle, and means for co-operating with the bent portion of pipe once the bending force has been removed, in order to determine the actual angle through which the pipe has been bent.
• an arrangement which is capable of turning to align with the bent portion of the pipe and has an associated means for indicating its angular position.
• This arrangement may comprise a mechanical feeler arrangement or an optical system.
• a camera may be provided to view the pipe from above.
• the camera may be mounted so as to be movable until the camera is viewing the bent portion of pipe, and a digital indication of the bend angle provided.
• the camera may be driven under numerical control to its required position, from the data which determines the angle through which the bending head was turned, or may reach this position through an adaptive procedure.
• the camera may instead be mounted beyond the front of the machine. Once the bend has been effected, the machine may then advance the pipe an appropriate distance (being the known distance of the camera in front of the machine) such that the bend in the pipe is aligned with the camera, then the pipe is clamped up to the bending head and the camera used to determine the actual angle of the bend.
• the camera may be mounted for movement cross-wise of the machine so that it can be moved out of way when not in use.
• the camera may be used before any bend is made on the pipe, with the pipe advanced to project out the front of the machine: the camera is now used to determine accurately the vector for the axis of the unbent pipe and can further be used to determine the width or diameter of the pipe, the latter providing data for use subsequently in defining the true centre line of the bent pipe.
• a digital indication of the angle through which the pipe has actually been bent can be provided, and compared with ⁇ in the control system with the command angle or angle thro ⁇ ugh which the bending head had been turned.
• the machine can automatically carry out two bends of significantly different angles (e.g. 20° and 120°) in a sample pipe, and its control system automatically calculate predictions for the spring-back at all bend angles, and automatically correct for all bends which are to be formed under a par ⁇ ticular part-program.
• the facility can also or instead be utilised as an in-progress check on the bends being formed on a part.
• the machine may automatically re-engage the pipe and bent it further, sufficient so that (taking account of the predi- cted further spring back if necessary) the bend in the pipe will be to the required angle.
• FIGURE 1 is a diagrammatic plan view of a pipe bend- . ing machine in accordance with this invention.
• FIGURE 2 is a diagrammatic section on the line II-II of the machine of Figure 1;
• FIGURE 3 is a diagram of the bending head after a bend in a pipe has been formed;
• FIGURE 4 is a sectional view on the line TV-TV of of Figure 3; and FIGURE 5 is a plan view of the bend head of a modi ⁇ fied machine having a camera to determine the bend angle.
• FIG. 1 and 2 of the drawings there is shown a pipe bending machine of the draw bending type.
• the machine comprises a- horizontal machine bed 9 mounting a bending head 10 at its forward end.
• This bending head comprises a bending die 12 of generally cylindrical form and mounted for rotation about its axis A, which is dis ⁇ posed vertically.
• the bending die 12 is formed with an annular groove 14 which is semi-circular in section, and is provided with a short, flat-faced, tangential exten- tion 12a_ which has a groove forming a tangential extension of the groove 14.
• a clamp block 16 is provided to co ⁇ operate with the bending die extension 12a, and is formed with a semi-circular section groove l6a_ across its face, so that it can clamp a pipe 1 against the bending die.
• the clamp block 16 is mounted to an arm 18 for sliding movement by an hydraulic actuator 17 towards and away from the bending die extension 12a_: the arm 18 is mounted for rotating about its axis A of the bending die 12 so that it will turn with the bending die during bending operation.
• the bending head 10 further comprises a pressure die 20 mounted to the machine bed 9 and having a flat front surface formed with a semi-circular section groove co ⁇ operating with the groove 14 of the bending die 12.
• This pressure die 20 is movable towards and away from the bend ⁇ ing die by an hydraulic' actuator 21, and is mounted so that it will move lengthwise of the pipe 1 during a bend- ing operation.
• a wiper die 22 may also be provided, fixed to the machine bed 9, positioned opposite the pressure die 20 and shaped at its forward end to fit close to the bending die 12.
• the flat surface of the wiper die 22 which faces the pressure die 20 is formed with a semi- circular section groove co-operating with the groove of the pressure die 20.
• the bending machine further comprises a pipe or tube holder 26 mounted to a carriage 24 which is mounted for sliding movement along the length of the machine bed 9 under the power of a motor 25 and via a drive belt 25a.
• the pipe holder 26 comprises a cylindrical body through which, in use, the pipe 1 extends, and is provided with a collet 26a_ which can be applied to grip the pipe.
• the pipe holder body is rotatable about its axis and coupled to a drive motor 27 for effecting this rotation.
• the bending machine also comprises a mandrel 28 carried at the end of a'mandrel rod 30, the mandrel being positioned in the pipe 1 to support the latter internally immediately upstream of the bend being formed, in use of the machine.
• the mandrel rod is mounted by a holder 31 to the machine bed beyond the trailing end of the pipe being processed.
• the machine is controlled by a computer numerical control system 50.
• the control serves to advance the carriage 24 to position the pipe 1 correctly, relative to the bending head, ready for the first bend to be made in the pipe 1.
• the pressure die 20 is advanced to press the pipe against the bending die 12 and wiper die 22, and the clamp ⁇ ing block is advanced to clamp the pipe 1 securely against • the bending die extension 12a.
• the bending die 12 and clamp arm 18 are turned together around the axis A of the bending die (and through the angle required), for example by a drive motor 45 applying power to a spindle 40 on which the bending die 12 is mounted ( Figure 2).
• the pressure die 20 slides forwardly in following a displacement of the pipe 1 which occurs, in the region of the bending head 10, as the bending die 12 turns.
• the clamp block 16 and the pressure die 20 are then retracted to free the pipe 1 from the bending die 12.
• the clamp arm 18 is returned to its initial position by a drive motor 47 coupled to it, the clamp arm 18 being journalled about the spindle 40.
• the carriage 24 is advanced an appropriate amount so as to position the pipe 1 correctly for the next bend.
• the bending die 12 is returned to its initial position by its drive mo-tor 45 and the pressure die 20 is also returned to its ori ⁇ ginal position.
• next bend in the pipe 1 is to be effected in a different plane from the first bend, then the pipe holder 26 is turned through an appropriate angle.
• the next bend in-the pipe 1 is then carried out in the same manner as just described, and the whole sequence of steps is repeated for all the following bends which are to be made in the pipe 1.
• the entire operation of the machine is under compu ⁇ ter numerical control from the control system 50, inclu ⁇ ding in particular the measured displacements of the carr ⁇ iage 24, pipe holder 26 and bending die 12 and the applica ⁇ tion/release movements of the clamp block 16 and pressure die 20.
• each finger 41, 42 includes a detector, so as to indicate if only one or other of them contacts the pipe 1 (indicating a misalignment) or if both of them contact the pipe 1 (indi ⁇ cating that the bending arm-18 is aligned with the pipe).
• the probe 41, 42 may be pivoted up manually, but the bending arm is provided with a rotary position encoder for giving a digital output signal indicating the angular position of the bending arm 18 when the alignment position is estab ⁇ lished: this output is provided to the compute numerical control system 50 of the machine, which serves to control the drives and displacements of the bending die, bending arm, clamp, carriage and pipe holder in accordance with a program or part-program defining the profile to which a pipe is to be formed.
• the bending arm 18 may be under automatic control of the control system 50 for this operation. For example, once the clamp 16 is released, the bending arm 18 may be driven back through an angle approximating to an expected spring-back angle: then the probe 41, 42 may be advanced automatically under the system control, which then serves to detect if both fingers 41, 42 of the probe make contact with the pipe 1. If one finger only makes contact, the bending arm 18 is turned through a small angle (in a direction determined by which finger 41 or 42 contacted the pipe 1) and the probe is used again: this procedure " is repeated until the probe indi ⁇ cates that the bending arm 18 is aligned with the sprung- back pipe 1. Then the control system 50 automatically reads the angular position of the bending arm 18.
• An electronic or video camera may be employed in ⁇ stead of the arrangement which has been described for deter ⁇ mining the actual angle of bend.
• the camera may be mounted so as to be movable in order to align with the bent portion of the pipe.
• the data which determines the angle through which the bending head was turned may be used to drive the camera under numerical control to the appropriate position, then the actual angle or offset angle of the bent portion of the pipe determined.
• the camera may reach this position through an adaptive proce ⁇ dure: for example, in the case of a camera with self- scanning array, the arrangement may be that the camera determines if the received image is at its centre of view or, if not, produces an error signal which is used to drive the camera until the image is centered.
• the self- scan array determines accurately and automatically the angle at which the bent portion of pipe lies.
• the camera VC may be mounted beyond the front of the machine and is preferably movable (for example cross-wise of the machine) so that it can be moved out of the way when not in use.
• the camera may preferably be movable under numerical control with respect to at least two axes, say cross-wise and lengthwise of the machine, or one linear axis and one rotational axis.
• the camera is movable (lengthwise of the machine) on a carriage 35 along a track 36 and this carriage is movable (cross-wise of the machine) along tracks 37..
• the machine may then advance the pipe 1 an appropriate distance out of the front of the machine and then the pipe 1 is clamped to the bending die 12 and the camera VC moved in to view the bent portion of pipe 1 in order to determine its actual angle automatically.
• the camera VC may ' :be used before any bend is made in the pipe 1, with the pipe 1 advanced to project out of the front of the machine: the camera VC is then used to determine accurately the vector for the axis of the unbent pipe 1 and also the width or diameter of the pipe 1. This vector may be determined as the average of a number of unbent pipes.
• the diameter data may be used subsequently for defining the true centre line of the bent pipe.
• each advancement may position the pipe 1 ready for the next bending operation, the camera being moved
• the system in accordance with this invention may be combined with arrangements for monitoring and/or com- pensating for pipe-elongation which occurs upon bending.

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

Applications Claiming Priority (4)

Publications (1)

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• 1986
  • 1986-09-18 EP EP19860905376 patent/EP0237543A1/de active Pending
  • 1986-09-18 WO PCT/GB1986/000557 patent/WO1987001625A1/en unknown

Non-Patent Citations (1)

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