Patent ID: 9308565
Filing Date: 2016-04-12
CPC Classification: B21D,Y10T

Claim Text:
1. A method for obtaining an opening in a hollow-body member having a longitudinal extension and a cavity, comprising: predisposing a holding die including a seat countershaped with respect to said hollow-body member and an ejection channel having a first end communicating with said seat and a second end for ejection; inserting and positioning said hollow-body member in said seat so that said first end is arranged in correspondence with a portion of a wall of said hollow-body member on which to obtain an opening; inserting a piston inside said cavity to compress an incompressible fluid with which said cavity is at least partially filled; and progressively increasing pressure inside said cavity sufficient to deform said wall portion to a point of detaching the wall portion from said hollow-body member to form said opening without burrs, and expelling said wall portion along said ejection channel, wherein one end of the cavity is open, an opposite end of the cavity is hermetically closed by a head of the hollow-body member, and a flange of the head rests on an outside surface of the holding die after the inserting and positioning said hollow-body member in said seat.