| 摘要 |
PURPOSE:To obtain a highly productive rotary hollow molding method by a method wherein mold clamping is done by employing toggle mechanism consisting of a plurality of links and hydraulic actuator in combination in order to obtain a molding by mold clamping. CONSTITUTION:Thermoplastic resin, which is kneaded, melted and extruded continuously from a die head 2 in the form of a parison so as to bite said parison with split molds 5 rotating always along the extrusion direction of the parison in order to blow compressed air through a needle buit in the mold and, after that, to clamp the mold by employing toggle mechanism consisting of a plurality of links and hydraulic actuator in combination during mold clamping. When links 15 and 16 are contracted, the amount of actuation of a cam roller 9 is increasingly transmitted to a retainer plate 11. When the links are stretched to their full lengths, the actuation of the retainer plate 11 is decelerated. The cam roller 9 is pressed until the links 15 and 16 stretch to their full lengths. When the links stretch to their full lengths, the cam roller 9 keeps its state and slides on a cam 10, resulting in not completely clamping the molds 5 so that a parison is bitten with the edge of the molds. Next, a hydraulic cylinder 12 buit in the retainer plate 11 is put into actuation so as to completely clamp the molds 5 in order to pinch off the parison 3.
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