Patent ID: 7326048
Filing Date: 2008-02-05
Classification: B29C

Abstract:
1. A valve nozzle, wherein in an internal space of a valve nozzle main body comprising a nozzle holder and a nozzle head attached to the front end of the nozzle holder, a gate opening and closing mechanism is disposed which comprises, in an integrally assembled manner; a piston having a head part and a shaft part formed continuously from the head part; a torpedo which is disposed in the internal space of the nozzle head and supported thereby, and which slidably supports and guides the piston, resin flow channels being provided between the outer surface of the torpedo and the inner surface of the nozzle holder; a coil spring which is disposed inside the torpedo and inserted with the shaft part of the piston, and presses the piston in the direction toward the gate; a cover which is attached to the rear end of the torpedo to close the rear end and serves as a spring receiving part of the coil spring; and when the resin pressure is at a predetermined value or less, the piston is pressed in the direction toward the gate by the coil spring and the entire circumference of the circular section of the head part of the piston comes into contact with the gate inner wall of the nozzle head to close the resin flow channels, and when the resin pressure becomes a predetermined value or more, the head part of the piston overcomes the pressing forces of the coil spring and withdraws from the gate of the nozzle head to release the gate; characterised in that the torpedo has an outer circumferential surface which contacts the inner circumferential surface of the nozzle holder to support the gate opening and closing mechanism, except where said outer circumferential surface is interrupted by grooves which provide said resin flow channels, said grooves being twisted with respect to the resin injection direction.