Metal pipe extruder - capable of adding the thrust advancing the press ram cross-head and the thrust returning the piercer mandrel cross-head

摘要

Metal pipe extrusion press has a stationary frame with a receiver and associated matrix supported by a cross-beam as well as a press ram supported by a cross-beam. The piercer mandrel is returned on its supporting cross-beam by a pressure cylinder, one end of which is directly connected with the cross-beam supporting the press ram, and the other end of which is connected to the corss-beam carrying the piercer mandrel. The press also has a holder which limits advancement of the cross-beam holding the piercer and has a pressure-fluid control system for controlling supply of pressure fluid to the pressure cylinder which advances the press ram cylinder's cross-beam, as well as to the pressure cylinder for returning the cross-beam holding the piercer, and to the pressure cylinder for advancing the piercer. This is effected with such force that the thrust developed by this pressure cylinder is greater than that developed by the pressure cylinder which returns the piercer cross-beam relative to the press ram cross-beam.