(19)
(11) EP 0 317 830 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
23.05.1990 Bulletin 1990/21

(43) Date of publication A2:
31.05.1989 Bulletin 1989/22

(21) Application number: 88118683.7

(22) Date of filing: 09.11.1988
(51) International Patent Classification (IPC)4: B21D 5/00, B21D 7/16, C21D 1/00
(84) Designated Contracting States:
DE ES FR GB IT

(30) Priority: 26.11.1987 PL 269039

(71) Applicant: Polska Akademia Nauk Instytut Podstawowych Problemow Techniki
PL-00-049 Warszawa (PL)

(72) Inventors:
  • Frackiewicz, Henryk
    PL-04-355 Warszawa (PL)
  • Mucha, Zygmunt
    PL-00-392 Warszawa (PL)
  • Trampczynski,Wieslaw
    PL-02-786 Warszawa (PL)
  • Baranowski, Adolf
    PL-02-610 Warszawa (PL)
  • Cybulski, Andrzej
    PL-01-957 Warszawa (PL)

(74) Representative: Finck, Dieter, Dr.Ing. et al
Patentanwälte v. Füner, Ebbinghaus, Finck Mariahilfplatz 2 - 3
81541 München
81541 München (DE)


(56) References cited: : 
   
       


    (54) A method of bending metal objects


    (57) This present invention solves the problem of bending objects, particularly flat parallel ones, without employing an external force.
    The method according to this present invention involves subjecting the material of the object bent to a repe­titive, two-phase heating and cooling process.
    During the first phase, the material undergoes heating with a concentrated stream of energy causing a thermal effect along the predetermined bending line and a partial plasticising, melting and flowing out in the region of the bending line.
    On the other hand, the material is subjected in the second phase to being cooled at ambient temperature or, additionally, in a stream of a blown air, thereby causing the previously heated material to shrink along fibres in the direction perpendicular to the bending line due to the internal stresses created by the thermal shrinkage of the material in the heated region, and thus the deformation of the material to be permanently changed.
    The method is suitable for bending metal objects.







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