Metal working – Method of mechanical manufacture – Shaping by direct application of fluent pressure
Reexamination Certificate
2001-09-17
2003-07-08
Vidovich, Gregory (Department: 3726)
Metal working
Method of mechanical manufacture
Shaping by direct application of fluent pressure
C029S897200, C029S525140, C029S557000
Reexamination Certificate
active
06588084
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for producing a circumferentially closed hollow profile.
BACKGROUND INFORMATION
International Published Patent Application No. WO 00/10748 describes a process for producing a hollow profile, in which a sheet-bar blank is rolled or formed into a hollow profile, is then welded along the edges which face one another, and finally undergoes a fluid-widening so as to match the form of the impression of an internal high-pressure forming die. This works without problems in the case of purely cylindrical or purely frustoconical hollow profiles. However, in the case of different desired geometries over the longitudinal extent of the hollow profile, as illustrated in
FIGS. 5 and 6
, are unable to offer a satisfactory solution, since as illustrated in
FIGS. 5 and 6
, during the rolling or forming of the sheet-bar blanks, the edges which are arranged opposite one another can in no way be made to completely abut one another, so that they can then be welded together in a simple manner. Rather, major welding work with filler or even additional metal sheets is required in order to close off the gaps which form. Moreover, at these locations, the weld seams which form extend so that they are highly unsuitable for subsequent internal high-pressure forming, due to their circumferentially oriented component, and have a tendency to tear during such a process.
It is an object of the present invention to provide a process with which circumferentially closed hollow profiles with a geometry which is frustoconical in sections may be produced as easily as possible and using a reliable process.
SUMMARY
The above and other beneficial objects of the present invention are achieved by providing a method as described herein.
In accordance with the present invention, the configuration of the sheet-bar blank and the combination of bending and compression movements of the sheet-bar blank make it possible to bring the side edges into abutment with one another. Consequently, the edges may easily be joined together without the use of fillers and other auxiliary materials, by longitudinal seam welding, to form the preform, which is near net shape, of the desired hollow profile before this preform is deformed into the final form by internal high-pressure fluid. The preform is in this case formed from a cylindrical section and a frustoconical section which axially adjoins the cylindrical section, the frustoconical section tapering outwardly away from its connection part. The special blank, which ensures that there is a transition between the frustoconical section and the cylindrical section of the hollow-profile preform without any gaps after the bending operation, allows pure longitudinal seam welding, in which the hollow-profile preform does not have any seam components extending in the circumferential direction, so that the fluid widening of the preform into the final form may be performed using a reliable process and without the risk of cracks forming in the seam. The process according to the present invention allows the production, with a reliable process, of hollow profiles in which there are changes in cross-section with a widening ratio at which—starting from a conventional tube blank of constant diameter—the elongation at break of the material used may be exceeded and therefore there may be an unavoidable risk of flaking or cracking during the widening operation. Consequently, it is possible to produce components that have cross-sections which vary in the axial direction. Even components that do not allow a weld seam in the circumferential direction, such as axle beams, may be manufactured in this manner.
REFERENCES:
patent: 3209432 (1965-10-01), Cape
patent: 3238610 (1966-03-01), Berg
patent: 3564896 (1971-02-01), Clark et al.
patent: 3890696 (1975-06-01), Buske
patent: 5333775 (1994-08-01), Bruggemann et al.
patent: 5735156 (1998-04-01), Yoshitomi et al.
patent: 6216509 (2001-04-01), Lotspaih et al.
patent: 6332346 (2001-12-01), Komiya et al.
patent: 6349521 (2002-02-01), McKeon et al.
patent: 52-46254 (1977-12-01), None
patent: 4-251612 (1992-08-01), None
patent: 00/10748 (2000-03-01), None
Daimler-Chrysler AG
Kenyon & Kenyon
Nguyen T.
Vidovich Gregory
LandOfFree
Process for producing a circumferentially closed hollow profile does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for producing a circumferentially closed hollow profile, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing a circumferentially closed hollow profile will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3099097