| 摘要 |
<p>PURPOSE:To enable to change a thickness of an arbitrary part of a parison, by moving a piece slidably along a groove by an actuator. CONSTITUTION:When a piece 13 is moved slidably in the direction separating from a flow pin 4 during extrusion of a parison, a slit 14 becomes wide, a flow distribution becomes large only on this part, elastic strain becomes great and the parison 19 which has become thick only on the right or locally is molded. When the piece 13 is restored to an orginal position, the same becomes the parison whose thickness is uniform. A thick part can be made on a necessary position in a circumferential and longitudinal direction of a molded article, by bringing the piece 13 close to or separating the same from a flow pin 4 like this. When the piece 13 is kept moved slidably and gradually extending from the beginning of extrusion of the parison to the termination of the same, the thickness changing extending over the whole length of the parison can be made.</p> |
