Patent ID: 7412866
Filing Date: 2008-08-19
Classification: B21C,B21K,B60B,Y10T

Abstract:
1. A method for manufacturing a tubular article, the tubular article defining a longitudinal axis along its length, the tubular article having a first end, an opposite second end and a main body extending between the first and second ends, the main body including a locally outwardly thickened first region spaced from the first end and a locally inwardly thickened second region between the first region and the second end, the second region being spaced from the second end, the first region having a first wall thickness, a first inner diameter and a first outer diameter, and the second region having a second wall thickness, a second inner diameter and a second outer diameter, the method comprising the steps of: a) providing a tubular blank, the tubular blank having an inner surface and an outer surface; b) axially inserting a mandrel into the tubular blank, the mandrel having a first mandrel end, a second mandrel end and a mandrel main body extending between the first and second mandrel ends, c) longitudinally forcing the tubular blank with the mandrel contained therein through a throat of a first die to deform the inner surface of the tubular blank to conform to the mandrel profile and to obtain a deformed tubular blank having a first thickened region and a second thickened region corresponding to the first and second sections of the mandrel, respectively; d) separating the mandrel from the deformed tubular blank while preventing the deformed tubular blank from passing through the throat, to cause outward deformation of the outer surface of the deformed tubular blank in the first and second thickened regions; and e) forcing inwardly the second thickened region of the deformed and separated tubular blank to form the second region of the tubular article.