| 摘要 |
A method for producing a bung for a metal cask that does not require a conventional collar and seal, and that simplifies the operations for forming the bung. The method disclosed in the present application includes the following steps. First, a prestamping operation creates a preforming dome in the wall of the cask such that a cuvett is formed. Second, an approximately cylindrical shaft is formed by stamping and thus puncturing the wall of the cask at the location of the bung. Third, the protruding edge of the shaft is folded down the to form an external rolled edge. Fourth, encircling the shaft with a rigid ring constituted by at least two annular sections such that the metal does not tear during the formation of the threads. Finally, the method of the present invention includes the step of implementing a roller threading head to form internal threads in the shaft. |
