Apparatus for preparing heat-set plastic hollow vessel

An apparatus for preparing a drawn heat-set plastic hollow vessel, which comprises:

• a rotary member having a plurality of openable-closable blow-forming and heat-setting molds and preform-supporting mechanisms corresponding to said molds,
• a preform supply mechanism for supplying a preform maintained at a drawing temperature into the mold of the rotary member at the opening position, and
• a vessel withdrawal mechanism for withdrawing a drawn and heat-set vessel from the mold of the rotary member at the opening position,
• an opening and closing mechanism for closing the molds after passage through the position of the preform supply mechanism and opening the molds before arrival at the position of the vessel withdrawal mechanism,
• a sealing member capable of reciprocating relatively to the preform supported by the preform supporting mechanism while having a sealing engagement with the mouth portion of the preform, and
• a hollow drawing rod arranged concentrically with the sealing member to reciprocate so that the drawing rod is inserted into the preform and drawn out thereform, wherein
• the rotary member comprises a mold-heating mechanism for maintaining the molds at a heat-setting temperature through the entire rotation course of the rotary member and
• wherein the apparatus additionally comprises
• a first gas passage formed between the periphery of the drawing rod and the sealing member having a sealing engagement with the mouth portion of the preform and leading to the interior of the preform,
• a second gas passage formed in the interior of the hollow drawing rod and leading to the interior of the preform through openings distributed in the length direction of the drawing rod,
• a high-pressure hot air supply mechanism and discharge mechanism connected to the first gas passage through an opening-closing or changeover valve,
• a cold air supply mechanism connected to the second gas passage through an opening-closing valve, and
• a mechanism for controlling the opening-closing or changeover valve, which connects the first gas passage to the high-pressure hot air supply mechanism synchronously with the insertion of the drawing rod into the preform to effect stretch drawing of the preform by the drawing rod and blow drawing of the preform by hot air and to confine hot air in the formed vessel for heat-setting the formed vessel and connects, after said heat setting, the first gas passage to the hot air discharge mechanism and the second gas passage to the cold air supply mechanism to effect the discharge of hot air and cooling of the vessel.