EXPANSION DUMMY BLOCK FOR EXTRUDING PRESS FOR HOLLOW BODIES

摘要

An expansion dummy block for extruding press for hollow bodies is described, the press comprising a container with a hole in which the material (323) to be extruded is inserted and a mandrel (327) for centrally perforating said material (323). The dummy block tightly slides inside the hole of the container pushed by a punch(304), and comprises: an internal hole for containing the mandrel (327) and let it slide therein; a head adapted to be elastically deformed so as to expand into the external edge contacting the container hole, and to expand into the internal edge (325) towards the internal hole contacting the mandrel (327) due to the reaction force produced by the contact with the material (323) upon the thrust received from said punch(304), and to withdraw when the reaction force is exhausted.