US Patent 7470123 Injection molding nozzle

In an injection molding nozzle with a nozzle head including at least one discharge opening and a closure element for closing the discharge opening movably supported in the nozzle head for closing the discharge in order to control the supply of melt material to a communication opening in an injection mold, the closure element is operable by a drive mechanism provided with a short stroke actuating means for displacing the closure element in a direction opposite to the closing direction of the closure element by a predetermined short distance so as to automatically retract the closure element by the predetermined short distance when it is no longer biased by the actuating means in the closing direction.