This invention is an improved injection molding nozzle whereby the shut-off plunger is operated by a fluid and the opening of the nozzle is accomplished by the flow of plasticized material through the nozzle. A control rod internal to the nozzle controls the movement of the plunger shut-off member and...http://www.google.es/patents/US4333608?utm_source=gb-gplus-sharePatente US4333608 - Injection molding nozzle
