EP0195408A2 - Flexibler Dorn zum Biegen hohler Gegenstände - Google Patents

Flexibler Dorn zum Biegen hohler Gegenstände Download PDF

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Publication number
EP0195408A2
EP0195408A2 EP86103646A EP86103646A EP0195408A2 EP 0195408 A2 EP0195408 A2 EP 0195408A2 EP 86103646 A EP86103646 A EP 86103646A EP 86103646 A EP86103646 A EP 86103646A EP 0195408 A2 EP0195408 A2 EP 0195408A2
Authority
EP
European Patent Office
Prior art keywords
mandrel
hoses
cross
bending
tubes
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.)
Ceased
Application number
EP86103646A
Other languages
English (en)
French (fr)
Other versions
EP0195408A3 (de
Inventor
James Donald Klingensmith
Robert Paul Evert
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.)
Howmet Aerospace Inc
Original Assignee
Aluminum Company of America
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 Aluminum Company of America filed Critical Aluminum Company of America
Publication of EP0195408A2 publication Critical patent/EP0195408A2/de
Publication of EP0195408A3 publication Critical patent/EP0195408A3/de
Ceased 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

Definitions

  • This invention relates to a flexible mandrel for bending hollow articles.
  • Bending a non-flexible hollow article involves some degree of risk of undesirable buckling or deformation of the article unless some means of internal support, such as a mandrel is utilized. While the insertion and use of a mandrel will serve to adequately support the walls of a hollow article during a bending operation, withdrawal of the mandrel after the bending function can present problems depending upon the complexity of the bend and the flexibility of the mandrel.
  • Zinnbauer et al U.S. Patent 3,841,138 proposes the use of stiff spherical balls within a tubular member to prevent collapse or buckling of the member during subsequent forming operations.
  • Himstedt U.S. 3,251,126 teaches the use of a burnable mass of fibrous filler mandrel to be used as a removable supporting mandrel when forming coils.
  • Gill U.S. Patent 3,016,081 uses a stack of substantially flat metal strips to internally support a waveguide during bending operations.
  • Kupfrian U.S. Patent 3,922,134 discusses the inadequacies of prior art approaches for supporting pipes during bending operations and then discloses the use of a helically wound expandable coil of flexible tubing, such as rubber wrapped around a flexible mandrel core.
  • the mandrel is inserted into a conduit to be formed and a pressurized fluid is applied to the expandable helically wound tubing to render the tubing turgescent or swollen.
  • the helical shape of the mandrel may give rise to the same objections raised by the use of a spring as well as complicate the subsequent withdrawal of the mandrel when used in soft hollow objects due to the helical nature of the indentations which may be made in the soft hollow object being bent.
  • an object of the invention to provide a radially expandable flexible mandrel to support the walls of a hollow member during forming operations.
  • a flexible mandrel for insertion into and removal from a hollow member and adapted to provide support for the walls of the hollow member in the process of bending the member, comprises a plurality of elongated individual hoses disposed together in a side-by-side manner to form a unitary, elongated mandrel structure, said hoses being capable of expanding in cross section when a fluid is directed to them under pressure at a predetermined pressure value and contracting in cross section when the pressure value is lowered to or below a predetermined value.
  • the cross-sectional expansion and contraction of the hoses are effective to expand and contract the cross-sectional area of the mandrel structure to provide the desired support while facilitating easy withdrawal of the mandrel.
  • the flexible mandrel of the invention generally comprises a plurality of yieldable tube member adapted to be disposed within a bendable hollow object generally parallel to the axis of the hollow object.
  • a mandrel constructed in accordance with the invention is generally indicated at 10 comprising a plurality of parallel flexible tubes 20 which are sealed at one end 22, for example, by plug means 26 and connected, at an opposite, open end 24, to a manifold 30.
  • a line 40 connected to manifold 30 supplies fluid pressure from a pneumatic or, preferably, a hydraulic source.
  • Tubes 20 are preferably constructed of a flexible, expandable material, such as a heavy gauge neoprene rubber to permit radial expansion of tubes 20 upon application of fluid pressure thereto through manifold 30.
  • the tube bundle in unpressurized or relaxed form, which maintains the integrity of its original shape wherein relaxed, is inserted into a hollow article 60, and fluid pressure is then applied to expand tubes 20 tightly against the surface of the inner wall of the hollow article as shown in Figure 2.
  • tubes 20 comprising mandrel 10 are supported or guided by a flexible frame comprising a pair of flexible sheets 44 and 48 having slotted openings 50 therein to receive flexible upright members 54 to form an eggcrate-like support frame for tubes 20.
  • a flexible frame comprising a pair of flexible sheets 44 and 48 having slotted openings 50 therein to receive flexible upright members 54 to form an eggcrate-like support frame for tubes 20.
  • Flexible sheets 44 and 48 and flexible upright members 54 may be constructed of a hard but somewhat flexible rubber or plastic, e.g., a hard vinyl.
  • Figures 6-7 illustrates another modification of mandrel 10 wherein a molded spline 70 made from hard rubber or similar materials is formed with grooves or keyways 72.
  • Divider members 80 having a first arm or wing 82 and a second arm 84 are secured to spline 70 via a tongue or key 88 thereon which is lockingly received in groove or keyway 72 by sliding key 88 into keyway 72 from the end of spline 70.
  • Divider members 80 may also be constructed of any flexible material having the required amount of stiffness to act as a guide for the nest of tubes comprising mandrel 10.
  • the length of the support frame may be easily altered by trimming sheets 44 and 48 or spline 70 to the desired length and then inserting, respectively, the appropriate number of upright members 54 or divider members 80.
  • FIG. 8-9 Yet another embodiment is illustrated in Figures 8-9.
  • the row of tubes 20 which will be next to the inner radius of the bent tubing is replaced by a flexible metal member which, in the illustrated embodiment, comprises a link chain 90, such as a bearing chain.
  • a series of alternately spaced links 92 comprising a metal, such as aluminum, are linked together by rods 94 of a hard aluminum or steel alloy passing through holes 96 in chain 90.
  • link chain 90 replaces the row of tubes 20 on the inside of the bend of hollow article 60 to provide the hardest--or most firm--support in the critical area most likely to crimp or buckle during the bending operation.
  • Inflation of hoses 20 retains chain 90 firmly against the wall of article 60 while deflation of tubes 20 allows mandrel 10 to be easily withdrawn from article 60.
  • the embodiments previously illustrated and described can, of course, be easily modified to accommodate the inclusion of chain 90 in mandrel 10 by appropriate modification of upright members 54 or divider members 80.
  • the invention provides a flexible mandrel comprising inflatable tubes disposed in a hollow article parallel to the axis of the article to permit easy insertion and withdrawal of the mandrel while providing maximum support to the walls of the article normal or perpendicular to the bending force applied thereto to inhibit or prevent buckling of the article during subsequent forming operation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Shaping Of Tube Ends By Bending Or Straightening (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)
EP86103646A 1985-03-21 1986-03-18 Flexibler Dorn zum Biegen hohler Gegenstände Ceased EP0195408A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US71436385A 1985-03-21 1985-03-21
US714363 2000-11-15

Publications (2)

Publication Number Publication Date
EP0195408A2 true EP0195408A2 (de) 1986-09-24
EP0195408A3 EP0195408A3 (de) 1987-04-29

Family

ID=24869738

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86103646A Ceased EP0195408A3 (de) 1985-03-21 1986-03-18 Flexibler Dorn zum Biegen hohler Gegenstände

Country Status (2)

Country Link
EP (1) EP0195408A3 (de)
JP (1) JPS61253126A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2200062A (en) * 1987-01-21 1988-07-27 Benteler Werke Ag A method of and apparatus for bending tubes

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1555895A (en) * 1924-11-03 1925-10-06 American Nat Company Method of bending sheet-metal blanks having alpha rolled edge
DE1552862A1 (de) * 1966-12-29 1969-09-11 Banning Ag Maschinenfabrik J Biegedorn fuer duennwandige Rohre
US3851519A (en) * 1972-06-06 1974-12-03 Crc Crose Int Inc Internal pipe supporting mandrel
DE2449221A1 (de) * 1973-10-17 1975-04-24 Pneumatiques Caoutchouc Mfg Ausweitbarer dorn oder kern zum biegen von metallrohren mit grossem durchmesser
US3922134A (en) * 1973-12-17 1975-11-25 Robintech Inc Pipe bending mandrel

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1555895A (en) * 1924-11-03 1925-10-06 American Nat Company Method of bending sheet-metal blanks having alpha rolled edge
DE1552862A1 (de) * 1966-12-29 1969-09-11 Banning Ag Maschinenfabrik J Biegedorn fuer duennwandige Rohre
US3851519A (en) * 1972-06-06 1974-12-03 Crc Crose Int Inc Internal pipe supporting mandrel
DE2449221A1 (de) * 1973-10-17 1975-04-24 Pneumatiques Caoutchouc Mfg Ausweitbarer dorn oder kern zum biegen von metallrohren mit grossem durchmesser
US3922134A (en) * 1973-12-17 1975-11-25 Robintech Inc Pipe bending mandrel

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2200062A (en) * 1987-01-21 1988-07-27 Benteler Werke Ag A method of and apparatus for bending tubes
GB2200062B (en) * 1987-01-21 1991-07-17 Benteler Werke Ag Apparatus for bending tubes.

Also Published As

Publication number Publication date
EP0195408A3 (de) 1987-04-29
JPS61253126A (ja) 1986-11-11

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Inventor name: KLINGENSMITH, JAMES DONALD