| 摘要 |
PURPOSE:To make the setting and use of a parison controlling apparatus possible and to obtain a blow molding of a uniform thickness by supplying a press- oil in upper and lower oil-pressure chambers of an oil-pressure cylinder and by expanding/contracting a to-air space of the sloping wall of a mandrel. CONSTITUTION:The thickness of a sloping wall port 12 between the sloping wall 10 of a top mandrel 6 and an opposite sliding piece 11 is controlled by supplying a press-oil in the upper space 7 and the lower space 8 of a packing box 5 of an upper oil-pressure cylinder 2. A parison 13 is prepared by spreading a plasticized material injected from a top nozzle 23 under uniform pressure from the central port 20 of a mandrel 9 to the whole surface of a die and by hanging it from the port 12. The thickness of the parison 13 can be adjusted by controlling the port 12 by means of a computer. As the area of the sloping wall 10 becomes a little larger than those of parison ports 14a, 14b and the difference between them become much smaller, the resistance under pressure increase against the top mandrel 6 on the side of the parison 13 is therefore very small and a small capasity of the upper oil-pressure cylinder 2 is enough. |
