Patent ID: 9486849
Filing Date: 2016-11-08
CPC Classification: B21C

Claim Text:
1. A double-action extrusion press comprising: a main crosshead which is adapted to be able to be pushed by a main cylinder in an axial direction and has an extrusion stem arranged at its front end; a piercer cylinder which can slide a mandrel in said extrusion stem and said main crosshead and is provided inside said main cylinder; container cylinders which can move a container which contains a billet in an axial direction; and a die stem which is inserted into said container, is facing said extrusion stem, and has a die arranged at its front end, wherein pressure receiving areas of cylinder chambers at the side for discharging working fluid from said container cylinders when said container moves in the extrusion direction and a pressure receiving area of a rod-side chamber of said piercer cylinder are set the same, and after completion of piercing when said extrusion stem pushes out said billet, said cylinder chambers at the sides for discharging working fluid from said container cylinders and a rod side of said piercer cylinder are connected by a hydraulic pipeline to be communicated with each other.