Metal deforming – By application of fluent medium – or energy field – With actuated tool engaging work
Reexamination Certificate
1999-01-21
2001-11-27
Hughes, S. Thomas (Department: 3726)
Metal deforming
By application of fluent medium, or energy field
With actuated tool engaging work
C072S041000, C072S342940, C072S370150, C029S421100, C029S527200
Reexamination Certificate
active
06321581
ABSTRACT:
The invention relates to a process for production of an area of increased wall thickness in a longitudinal section and to a device for application of the process.
A process such as this for production of increased wall thickness has been disclosed in SU-A-1417954, FIG. 1. In the process a longitudinal hollow section is secured in a die matching the external dimensions of the die, is subjected to axial pressure by an axial piston applying pressure on both sides, and in addition the profile cavity is subjected to radial pressure by a suitable medium. A hollow section is produced as a result, one which undergoes reduction of the internal cross-section over the entire length so that increased wall thickness is obtained.
German patent application 44 37 395 A1 describes a process for shaping a pipe end in which the pipe to be shaped is subjected to internal and external axial pressure, the pipe being secured in a die corresponding to the exterior dimensions of the pipe, and in the end area of the pipe to be shaped the die also being provided with a shape matching the final dimensions of the pipe after the shaping process and the pipe being subjected in the area to be shaped to end pressure by at least one axial piston and at the same time to radial pressure by a fluid.
The practice of shaping hollow sections by axial pressure and by radial pressure applied simultaneously by means of a fluid is known under the designation “internal high pressure shaping” (see DE-A 29 35 086, EP 0 484 789 B1). Such a process does not involve increase in the wall thickness in the hollow section shaped; what results is rather reduction in the thickness of the remaining wall by extension of the material. A process for upsetting section ends by plastic deformation by means of a stepped axial piston is disclosed in U.S. Pat. No. 5,203,194. Introduction of additional radial pressure by means of a fluid is not provided in this process.
Patent application DE 44 37 395 A1 is concerned primarily with plastic deformation of pipe ends for the manufacture of optimized-mass and long-lived exhaust systems for internal combustion engines. Areas of such subassemblies with cross-sectional dimensions modified on the basis of function serve the purpose, for example, of fastening special machine elements or subassemblies. Such subassemblies and machine elements may be represented, among other things, by sound absorbers, catalysts, or fitting flanges.
The object of Patent Application DE 44 37 395 A1 is development of a process for upsetting pipe ends and a device for application of the process by means of which a tubular element having generally optimum cross-sectional dimensions may be provided with end sections having larger cross-sectional dimensions so that the internal diameter remains unchanged, virtually free of a transitional area, even in the area of the pipe end, and yet the cross-sectional dimensions required remain available for the joining of additional components, by welding for example.
The object of the invention is to increase the shaping options of the state-of-the-art process as described in the preamble of Claim
1
in order to produce an area of increased wall thickness in an oblong hollow section. Modification of the internal cross-section of the hollow section is not to take place in the process.
The solution claimed for the invention is to be seen from the descriptive portion of Claim
1
and is based on a procedure as specified in the preamble of Claim
1
.
By application of this process more or less minor tool modifications need be made to provide any given area between section ends with increased wall thickness rather than the entire length of a hollow section, the internal cross-section remaining the same. The hollow section itself may be of any desired cross-sectional shape (e.g., rectangular, as specified in U.S. Pat. No. 5,203,194, round, polygonal, open or closed, etc). The only requirement for this purpose is that dies or axial pistons have the same shape.
In addition, the hollow section may consist both of a metallic and a nonmetallic material (such as a plastic).
The areas situated between the ends of a section and also the section ends may be upset and provided with increased wall thickness in the concomitant plastic deformation.
REFERENCES:
patent: 2313116 (1943-03-01), Babcock
patent: 3950975 (1976-04-01), Izumi et al.
patent: 5956988 (1999-09-01), Beste et al.
patent: 0502773 (1952-08-01), None
patent: 291212 (1916-04-01), None
patent: 0144210 (1989-02-01), None
patent: 61253133 (1986-11-01), None
patent: 0245940 (1989-10-01), None
Fischer Frank
Haldenwanger Hans-Gunther
Oswald Jurgen
Wenzel Holger
Audi AG
Compton Eric
Hughes S. Thomas
Lalos & Keegan
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