| 摘要 |
PURPOSE: To prevent the contamination of a molten resin with gas by utilizing the compressed fluid from a fluid source as at least a part of second pressure to set the tip of a valve means to a closing position. CONSTITUTION: During the operation of a nozzle 106, a tip part 150 is moved by the variable pressure exerted by the molten resin on the surface 140 of a first piston member 136. Subsequently, the molten resin flows in a mold cavity 116 through the nozzle 106. After the resin is injected, a pin 148 advances and the tip part 150 is moved to a closing position by the deflection action of a spring 147 and the fluid pressure action by a ball 154. Thereafter, the additional pressure by gas separates the ball 154 from a plug 160 and the gas flows through the opening 156 in the pin 148. After the gas is injected, a gas valve 26 is closed and a check valve 152 prevents the back flow of the gas. The pressure difference above a valve mechanism 132 prevents the contamination of the molten resin in a nozzle main body 108 with gas. |
