Paste extruder

An apparatus for extruding plastic tubing, comprising

• (a) a machine stand;
• (b) an extrusion cylinder supported by said machine stand;
• said extrusion cylinder including an interior space for receiving a plastic preform to be extruded from said cylinder;
• (c) a housing;
• (d) mounting means for supporting said housing on said machine stand;
• (e) a hollow extrusion piston introducible into and withdrawable from said extrusion cylinder;
• (f) an extrusion drive means positioned in said housing and connected to said extrusion piston for advancing said extrusion piston into and for withdrawing said extrusion piston from said extrusion cylinder;
• said extrusion drive means including a hollow cylinder;
• (g) a mandrel pulling rod mounted in, and axially displaceable relative to, said hollow extrusion piston;
• (h) a mandrel affixed to said mandrel pulling rod and moving as a unit with said mandrel pulling rod;
• said mandrel being introducible into and withdrawable from said extrusion cylinder;
• and
• (i) mandrel actuating means circumferentially surrounded by said hollow cylinder of said extrusion drive means in said housing and connected to said mandrel pulling rod for axially displacing said mandrel pulling rod;
• said mandrel actuating means comprising a hollow mandrel-driving piston connected to said mandrel pulling rod and hydraulic means for displacing said mandrel-driving piston;
• (j) an adjustable abutment means for limiting a stroke of said mandrel-driving piston;
• said adjustable abutment means comprising an abutment member slidably received in said mandrel-driving piston;
• and
• (k) motor means connected to said abutment member for axially displacing said abutment member;
• said motor means comprising a spindle drive connected to said abutment member and being mounted on said housing coaxially with said extrusion drive means and said mandrel actuating means.