Closure and expression plunger for cartridges for plastic masses and method for inserting such a plunger into a cartridge

摘要

The closing and ejection piston has a piston plate (1) and a cylindrical streamlining (2), where a transition area is formed between the piston plate and the cylindrical streamlining with V-shaped cross-section. A sealing lip (3) is formed on a periphery and contains a stacking ring. Two axial projections are distributed equally on the periphery at the backward facing end surface of the stacking ring. An independent claim is included for a method for inserting a piston in the open rear end of the cartridge.