EP0901847A1 - Dorn zur Stützung der Innenwandung eines Rohres während dessen Kaltumformung in einer Presse - Google Patents

Dorn zur Stützung der Innenwandung eines Rohres während dessen Kaltumformung in einer Presse Download PDF

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Publication number
EP0901847A1
EP0901847A1 EP97830447A EP97830447A EP0901847A1 EP 0901847 A1 EP0901847 A1 EP 0901847A1 EP 97830447 A EP97830447 A EP 97830447A EP 97830447 A EP97830447 A EP 97830447A EP 0901847 A1 EP0901847 A1 EP 0901847A1
Authority
EP
European Patent Office
Prior art keywords
disks
elastically deformable
pipe
bending
rods
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97830447A
Other languages
English (en)
French (fr)
Inventor
Andrea Villa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tractor System Equipment Di Villa Rag Andrea & C SNC
Original Assignee
Tractor System Equipment Di Villa Rag Andrea & C SNC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tractor System Equipment Di Villa Rag Andrea & C SNC filed Critical Tractor System Equipment Di Villa Rag Andrea & C SNC
Priority to EP97830447A priority Critical patent/EP0901847A1/de
Publication of EP0901847A1 publication Critical patent/EP0901847A1/de
Withdrawn legal-status Critical Current

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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
    • B21D9/01—Bending tubes using mandrels or the like the mandrel being flexible and engaging the entire tube length
    • B21D9/03—Bending tubes using mandrels or the like the mandrel being flexible and engaging the entire tube length and built-up from loose elements, e.g. series of balls

Definitions

  • the present invention relates to a device for supporting the inside wall of a pipe during the cold bending of the same pipe by means of a press.
  • a structure to support the inside wall of the pipe known generally as a bending mandrel, to avoid deformation of the inner section of the pipe and the wrinkling of the same pipe which is found prevalently on the inside curve of the bending.
  • the device comprises essentially an hydraulic actuator which allows to compress a plurality of close-packed elastically deformable disks made of urethane and mounted freely slidable on a structure of rigid rods or tie rods.
  • the package of disks is replaced by a single elastically deformable tubular element mounted on a hollow shaft made of spring steel. In either case, the disks or the tubular element is compressed by a piston operated by the hydraulic actuator against a fixed flange at the opposite extremity with respect to the hydraulic actuator.
  • the devices so produced have various drawbacks.
  • the elastic support elements are mounted freely-slidable and operated by means of rigid rods. In this case, the stress generated by bending the pipe is therefore absorbed by the elastic material alone.
  • one of the main drawbacks of the device thus produced is the irregular deformation of the material of the elastic support elements.
  • the object of the present invention is to propose a device, or bending mandrel, to support the inside wall of a pipe during cold bending which uniformly distributes the supporting pressure along the inside wall of the pipe for all the length involved in the bending.
  • Another object of the present invention is to propose a device, or bending mandrel, that requires reduced operating costs and maintenance compared with known types of mandrels.
  • a further object of the present invention is to propose a device, or bending mandrel, which is less cumbersome and therefore can also be used for bending small diameter pipes.
  • a device for the cold bending of pipes in a bending press of the type comprising a plurality of substantially cylindrical elastically deformable disks as a means for supporting the inside wall of the pipe to be bent, and means for causing the radial expansion of the disks, characterised in that the means for causing the radial expansion of the disks comprise one or more substantially rigid separator elements between the disks.
  • the compression pressure of the hydraulic actuator is substantially uniform on all the disks and their deformation in the radial direction is equally uniform.
  • the principal function of the separator elements is to allow a correct and uniform radial expansion of the elastically deformable disks.
  • the device according to the invention allows substantially uniform pressure to be exerted on all the inside wall of the pipe for all of the length involved in the bending.
  • the package comprising the elastically deformable disks and their related separator elements is contained between two substantially rigid extremity flanges which act respectively on the first and last of the elastically deformable disks.
  • the surfaces of the separator elements and of the flanges in contact with the elastically deformable disks are conical.
  • the conical surfaces are each oriented with the vertex turned toward the surface of the disk with which they are mutually in contact. That allows the elastic disks to deform in such a way as to keep as much as possible the configuration of the cylindrical side surface of each disk in contact with the inside wall of the pipe.
  • the device preferably comprises a plurality of cylindrical rods inserted into a central through hole in the disks and the separator elements, and each connected at their adjacent extremities to one or more articulation elements. In this way, the articulated rods follow the bending imparted to the pipe while avoiding excessive or irregular deformations of the elastic disks.
  • At least one articulation element is arranged between a first and a last elastically deformable disks.
  • more inter-rod articulation elements could also be provided.
  • a further articulation element is provided between the shaft of the hydraulic actuator and one of the rods.
  • the hydraulic actuator preferably comprises a double-acting cylinder.
  • Such a cylinder moves a mobile, substantially rigid extremity flange, bound to the extremity of one of the rods, in order to cause the radial expansion of the disks.
  • the mobile flange acts on the last elastically deformable disk, while at the opposite end, integral with the body of the double-acting cylinder, there is a fixed extremity flange which acts on the first elastically deformable disk.
  • the elastically deformable disks are made of elastomeric polyurethane and comprise a recess on each face to receive the separator elements in a such way as to retain the separator elements in the correct position when the mandrel is not in tensioned state.
  • the device shown in Figure 1 comprises a plurality of disks 1, made of an elastically deformable material, which form the means of supporting the inside wall of the pipe to be bent.
  • the entire package of disks 1 is held between a substantially rigid extremity flange 2, fixed to the body of a hydraulic actuator 5 by means of a series of columns 3 and a couple of rigid plates 4.
  • the flange 2 is therefore in contact with a first one of the disks 1.
  • the device At the opposite end of the package of disks 1, the device is provided with an extremity flange 6, connected to the shaft 7 of the hydraulic actuator 5 by means of a series of cylindrical rods 8a and 8b.
  • the flange 6 is therefore mobile with respect to the structure of the device and is in contact with a last one of the disks 1.
  • the cylindrical rods 8a and 8b are inserted into central through holes in the disks 1 and are mutually connected at their adjacent extremities by an articulation element 9.
  • the latter is preferably arranged inside the package of elastically deformable disks 1.
  • a further articulation element 10 is preferably provided between the shaft 7 of the hydraulic actuator 5 and the extremity of the rod 8a.
  • the hydraulic actuator 5 comprises preferably a double-acting cylinder, in a such way as to allow not only the drawing in of the flange 6, but also its commanded release to accelerate the elastic recovery of the disks 1 to their normal configuration.
  • Figure 2 shows the support device in tensioned state inside a pipe 15 before the bending of the same pipe.
  • the device is inserted into the pipe 15 in non-tensioned state ( Figure 1), and then oil under pressure is fed to the hydraulic actuator 5 by means of one of the supply lines 12 of the fluid under pressure.
  • the piston 14 draws in the shaft 7, the rods 8a and 8b, and therefore the flange 6, to compress the package formed by the disks 1 and the separator elements 20 between the same mobile flange 6 and the fixed flange 2, thus causing the radial expansion of the same disks.
  • the side surfaces of the disks are pressed against the inside wall of the pipe 15 forming a substantially continuous surface of contact and exerting sufficient pressure to support the wall of the pipe during bending.
  • the pipe 15 can be bent in the press (not shown) through a small angle ⁇ ( Figure 8) without suffering wrinkling or flaws.
  • the articulation elements that connect the rods 8a and 8b as well as the rod 8a with the shaft 7, comprise for instance pivots 9 and 10 inserted into transversal through holes in proximity of the extremities of the rods, in such a way as to allow the relative rotation around the pivots of the rods and of the shaft.
  • the surfaces 21 of the separator elements 20 which are in contact with the disks 1 are preferably conical, with the vertex 22 of the generating cone turned toward the surface of the disk 1 with which it is respectively in contact.
  • the angle ⁇ between the inclination of the conical surface and a corresponding plane surface is preferably less than 5°. However, different angles can also be selected depending on the material used for the elastically deformable disks and on the external diameter of the same disks.
  • the separator elements 20 comprise substantially rigid rings, for instance made of steel, and are of external diameter less than that of the elastically deformable disks 1.
  • the rings 20 have a central through hole 23 of diameter larger than the external diameter of the rods 8a and 8b to allow movement of the same rods with respect to the rings 20 during the bending of the pipe.
  • the flanges 2 and 6 also made of steel, have a conical surface on the face in contact with the respective extremity disks 1. Furthermore, the flange 2 has a central through hole 23 substantially similar in diameter to the hole of the separator elements 20.
  • Figures 6 and 7 show an elastically deformable disk 1 preferably made of elastomeric polyurethane, for instance that distributed under the VULKOLLAN trademark by Bayer, with a Shore hardness rating between 70 and 100. Other suitable materials are for instance those commercially distributed with the trademarks ADIPRENE and PHILAN.
  • the disk 1 is substantially cylindrical with a pair of base surfaces on which are provided recesses 31 that retain the respective separator elements 20.
  • the disks 1 each have a central through hole 32 substantially identical in diameter to the external diameter of the cylindrical rods 8a and 8b.
  • the external diameter of the disks 1 is selected depending on the diameter of the pipe to be bent and depending on the characteristics of the material of the same. In general, the external diameter of the disks 1 in their normal state is about 2-15% less than the diameter of the pipe to be bent. This value varies, however, depending on different factors, such as the type of material from which the disks 1 are made, their dimensions and the desired angle through which the pipe will be bent.
  • Figure 8 shows a pipe 15 that has been subjected to bending through an angle ⁇ while using a device according to the invention.
  • the disks 101, 201, and 301 in correspondence to the point of bending are deformed in such a way as to maintain a continuous surface of contact between the same disks and the inside wall of the pipe 15.
  • the rods 8a and 8b have been clearly rotated around the pivot of articulation 9 and there has also been a slight rotation (not shown in Figure 8 for the sake of simplicity) around the articulation pivot 10 between the rod 8a and the shaft 7 of the hydraulic actuator 5.
  • the rotation around the pivot 10 would be more evident, however, for more pronounced angles of bending than that indicated in figure, or for bending in more distant points from that represented in Figure 8.
  • the hydraulic actuator 5 is operated by sending fluid under pressure to the supply line 13, in such a way as to facilitate the rapid return of the disks 1 to their normal shape. At this point, the device could be moved in correspondence of a new point of bending.
  • suitable means to allow the movement of the device to be commanded can also be provided, for instance, hydraulic motors or the like.
  • the particularly simple construction and reduced bulk of the device according to the invention also allows its use with pipes of particularly reduced internal diameter, i.e. internal diameter between 152.4 mm (6 inches) and 304.8 mm (12 inches).

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)
EP97830447A 1997-09-15 1997-09-15 Dorn zur Stützung der Innenwandung eines Rohres während dessen Kaltumformung in einer Presse Withdrawn EP0901847A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP97830447A EP0901847A1 (de) 1997-09-15 1997-09-15 Dorn zur Stützung der Innenwandung eines Rohres während dessen Kaltumformung in einer Presse

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP97830447A EP0901847A1 (de) 1997-09-15 1997-09-15 Dorn zur Stützung der Innenwandung eines Rohres während dessen Kaltumformung in einer Presse

Publications (1)

Publication Number Publication Date
EP0901847A1 true EP0901847A1 (de) 1999-03-17

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP97830447A Withdrawn EP0901847A1 (de) 1997-09-15 1997-09-15 Dorn zur Stützung der Innenwandung eines Rohres während dessen Kaltumformung in einer Presse

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Country Link
EP (1) EP0901847A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110102618A (zh) * 2019-05-13 2019-08-09 浙江大学 一种用于飞机发动机金属导管弯曲的弹性双支撑变径芯棒
CN110893427A (zh) * 2019-12-23 2020-03-20 江苏金鑫电器有限公司 一种螺旋焊管的弯曲工装

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4378689A (en) * 1980-01-04 1983-04-05 W. Eckold Ag Core for a pipe that is to be bent
US4493203A (en) * 1983-01-26 1985-01-15 Crutcher Resources Corporation Resilient internal mandrel
US4671096A (en) * 1985-09-23 1987-06-09 Lockheed Corporation Adjustable ball mandrel
US5564303A (en) * 1995-06-07 1996-10-15 Buchanan; Robert W. Internal mandrel for use in pipe bending

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4378689A (en) * 1980-01-04 1983-04-05 W. Eckold Ag Core for a pipe that is to be bent
US4493203A (en) * 1983-01-26 1985-01-15 Crutcher Resources Corporation Resilient internal mandrel
US4671096A (en) * 1985-09-23 1987-06-09 Lockheed Corporation Adjustable ball mandrel
US5564303A (en) * 1995-06-07 1996-10-15 Buchanan; Robert W. Internal mandrel for use in pipe bending

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110102618A (zh) * 2019-05-13 2019-08-09 浙江大学 一种用于飞机发动机金属导管弯曲的弹性双支撑变径芯棒
CN110102618B (zh) * 2019-05-13 2020-07-14 浙江大学 一种用于飞机发动机金属导管弯曲的弹性双支撑变径芯棒
WO2020228840A1 (zh) * 2019-05-13 2020-11-19 浙江大学 一种用于飞机发动机金属导管弯曲的弹性双支撑变径芯棒
US11331709B1 (en) 2019-05-13 2022-05-17 Zhejiang University Elastic double-support variable-diameter mandrel for bending of aircraft engine-specific metal conduit
CN110893427A (zh) * 2019-12-23 2020-03-20 江苏金鑫电器有限公司 一种螺旋焊管的弯曲工装
CN110893427B (zh) * 2019-12-23 2024-04-26 江苏金鑫电器有限公司 一种螺旋焊管的弯曲工装

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