The operation of the first transfer mechanism 13 will now be described. A plurality of heating sections 24( 1) to 24( 5) are disposed along the transporting path 23 and while the respective mandrel carriers 22 that have received the preforms 2 from the second transfer mechanism 18 are transported along the transporting path 23, the mandrel carriers 22 pass the heating sections so that the preforms 2 are heated to a temperature condition suited to blow-molding. The transporting path 23 includes a semicircular transportation passage part 25 (an arc-shaped transportation passage part) that receives the preforms 2 from the fourth circular transportation passage 17 of the second transfer mechanism 18 and causes the preforms 2 to be supported on mandrel carriers 22. Here, the heating station 4 has a driving sprocket 19 and a driven sprocket 20, a chain 21 that is suspended between the sprockets, and mandrel carriers 22 that are attached to the chain 21 at fixed intervals, with the mandrel carriers 22 being transported along a transporting path 23 of a flat oval shape. The preform supplying station 3 includes a guide rail 8 that is inclined downward towards a supplying end, with flanges 2 b of opening parts 2 a of each preform 2 hung from the guide rail 8 and the preforms 2 in this upright state sliding downward along the guide rail 8 due to their own weight (the preforms 2 are described later with reference to FIG. In the illustrated example, a biaxial stretch blow molding apparatus 1 is a manufacturing apparatus for PET bottles used for drinks, for example, and has a preform supplying station 3 that supplies preforms 2, a heating station 4 that heats the preforms 2 to a temperature state suitable for blow-molding while transporting the preforms 2, a rotary-type blow station 6 that molds PET bottles 5 (blow-molded products) by blowing the heated preforms 2, and a collection station 7 that collects the PET bottles 5. 1 is a plan view schematically showing an overall construction of a biaxial stretch blow molding apparatus according to an embodiment of the present invention. 34 sixth circular transportation passage.26 fifth circular transportation passage.17 fourth circular transportation passage.14 third circular transportation passage.12 second circular transportation passage.9 first circular transportation passage.
1 biaxial stretch blow molding apparatus.However, since the conventional mold opening/closing mechanism is elongated in the planar direction toward the center of rotation of the turntable from the respective blow-molding molds, there is the problem that in order to avoid interference with the mold opening/closing mechanism, the bearing members have to be positioned close to the center of rotation of the turntable. Accordingly, it is preferable for bearing members that rotatably supports the turntable to be disposed as close as possible to a position directly below heavy objects, that is, directly below the blow-molding molds on the turntable. Here, a large number of heavy blow-molding molds are mounted on the turntable and the transporting of the respective blow-molding molds needs to be carried out precisely. In the mold opening/closing mechanism for blow-molding molds that can open and close laterally in the conventional blow molding apparatus, the link mechanism comprising the mold opening/closing mechanism extends from rear surfaces of the respective blow-molding molds in a planar direction toward a center of the turntable that rotates the respective blow-molding molds. The gripper devices are each held by a swing mechanism that swings the gripper device in a lateral direction and a linear movement device that linearly moves the gripper device in a anteroposterior direction, and are constructed so that when preforms are received, the respective gripper devices are transported while receiving the preforms so as to have the same feed pitch as the preforms transported with the narrow feed pitch in this movement mechanism. As disclosed in Reference Document 2 indicated below, as one example of a mechanism for transporting the preforms while increasing the feed pitch, a mechanism in which preforms that are transported along a circular transportation passage with a narrow feed pitch are gripped by gripper devices transported along a separate circular transportation passage with a large feed pitch is known. When the preforms are transferred from the heating station to the blow station after heating, it is necessary to increase the feed pitch so as to match the feed pitch of the blow-molding molds. In the blow molding apparatus of this construction, a large number of preforms can be heated efficiently and apparatus size can be reduced by transporting the preforms with a narrow feed pitch within the heating station.
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