| 摘要 |
PURPOSE:To eliminate complicated preparatory operation and increase the yield of product by completing mold clamping when parison exactly reaches its proper position by a method wherein the starting time for driving a mold clamping hydraulic cylinder device, which moves at constant speed, is controlled in response to the drooping speed of the parison. CONSTITUTION:By lowering continuously, parison 12 firstly intercepts the light path of an upper photoelectric sensor 38 and, after that, that of a lower photoelectric sensor 40. Accordingly, when the tip of the parison 12 is detected with the photoelectric sensor 38, the measurement of time is started. And, when the tip of the parison 12 is detected with the lower photoelectric sensor 40, the measurement of time is completed. By inputting the measured times to the speed calculating section 44 of a controlling device 42, the drooping speed of the parison is calculated. By inputting the calculated result in a valve opening timing setting circuit section 46, the arrival time of the parison 12 to its proper position is calculated so as to adjust the excitation time of a timing timer in proportion to said time in order to control the starting time of mold clamping. Thus, the clamping of a mold 14 is completed just when the parison reaches its proper position. |
