Patent ID: 9302307
Filing Date: 2016-04-05
CPC Classification: B21D

Claim Text:
1. A method of forming a hollow body with a flange, the method comprising: providing a tubular blank; placing the tubular blank between a first die half and a second die half, each of the first and second die halves having a body forming cavity portion and a flange forming cavity portion; applying an internal hydraulic pressure to the tubular blank while the tubular blank is within said body forming cavity portion and said flange forming cavity portion; closing the first and second die halves on the tubular blank whereby the body forming cavity portions form the hollow body and the flange forming cavity portions form a hollow flange extending from the hollow body wherein the hollow flange has a hollow space defined in part by spaced apart internal surfaces of the hollow flange and by an abutment interface whereby the internal surfaces come together and contact each other; opening the first and second die halves; removing the hollow body and hollow flange out of the first and second die halves; and flattening the hollow flange after the hollow body and hollow flange have been removed from the die halves whereby confronting internal surfaces of the hollow flange are brought together to abut each other and form a flat flange.