extrusion head for hollow body blow molding with a preform wall thickness distribution system

摘要

Extrusion head for blow molding of hollow bodies with a system for distributing the thickness of the preform walls. An extrusion head (1) for blow molding of hollow bodies, comprising: a body (2) and a power plug (3) arranged inside the body in order to define a cylindrical gap (4), through which it can flow the plastic material fed by an extruder; an opening (6) of the matrix disposed at the bottom end of the body (2); and a bottom part (30) of the power plug (3) disposed within the opening (6) of the matrix in order to define a cylindrical gap (10) in communication with said cylindrical gap (4) for the outlet of the tubular preform said extrusion head; and a plunger (20), supporting, at the bottom, an oval-shaped graft (40), being slidably mounted inside the chamber (32) formed in said bottom part (30) of the power plug. The plunger can move from a retracted resting position, in which the bottom edge (48) of the oval-shaped graft is located within said chamber (32) of the bottom part of the power plug, to a distended operational position, in the which the bottom edge (48) of said oval-shaped graft projects on the bottom with respect to the bottom edge (38) of said bottom part of the power plug.