| 摘要 |
<p>PROBLEM TO BE SOLVED: To make a resin flow near a gate excellent, and reduce the residual stress near the gate by a method wherein a gate opening and closing mechanism consisting of a spool having notched parts and arrow feather-like projections and a coiled spring biassing the spool to the direction opposite to a gate direction is arranged in the interior space of a nozzle head at the tip of a nozzle holder. SOLUTION: A nozzle head 10 has a gate 11 made of two stepped circular hole at its tip center and is detachably mounted at the tip of a nozzle holder 12 by means of a screw mechanism. A spool 20 consists of a tip head portion 21, an intermediate shaft part 22 and arrow feather-like projections 23 arranged at its rear end. The spool 20 is biassed toward an upper right direction by a coiled spring 30. The head portion 21 of the spool 20 has a circular section near its tip and notched parts formed in succession. Accordingly, under the state that a nozzle is closed, the outer periphery of the circular sectional portion near the tip of the head portion 21 abuts against the inner wall of the circular hole of the gate 11, resulting in closing a resin flow passage.</p> |
