Abstract: A blow molding machine for the manufacture of products such as bottles from a continuously extruded parison of plastic material. Two pairs of horizontally reciprocable mold sections alternately take a parison from a central station and transport it to either of two blow molding stations having vertically movable blow pins. The mold section platens carry laterally extending trimming elements and, when each pair of mold sections returns to retrieve another parison, the trimming elements trim flash from the molded product which hangs from the blow pin. The product is then transported to a delivery station by the trimming elements as the mold sections return to the blow molding station. The platens and blow pin stations are all supported by the vertically reciprocable table. As a knife severs the parison held by a pair of mold sections from the extruder and the mold sections start moving toward the mold station, the table lowers to prevent resticking of the material being continuously extruded.

Abstract: A blow molding machine for the manufacture of products such as bottles from a continuously extruded parison of plastic material. Two pairs of horizontally reciprocable mold sections are shown which alternately take a parison from a central station and transport it to either of two blow molding stations having vertically movable blow pins. The mold section platens carry laterally extending trimming elements and, when each pair of mold sections returns to retrieve another parison, the trimming elements trim flash from the molded product which hangs from the blow pin. The product is then transported to a delivery station by the trimming elements as the mold sections return to the blow molding station. The platens and blow pin stations are all supported by a vertically reciprocable table. As a knife severs the parison held by a pair or mold sections from the extruder and the mold sections start moving toward the mold station, the table lowers to prevent resticking of the material being continuously extruded.

Abstract: A construction for neck forming in a blow molding machine of the type having a retractable blow pin at a station separate from the parison extruding station. The construction results in a clean, non-fuzzy neck edge requiring no subsequent cleaning operation, and facilitating stripping of the product from the blow pin. The machine comprises a floating hardened shear ring as part of the blow pin assembly which has an interference fit with flared hardened inserts on the neck portion of the mold halves, thus creating a sharply defined upper neck edge. Means are provided for momentarily releasing downward pressure on the blow pin assembly as the mold halves are being retracted to prevent damage to the inserts. The blow pin assembly incorporates a self-centering arrangement for this shear ring and a controlled compressed air leakage system which cools and spreads the hot flash in the vicinity of the blow pin.

Abstract: Means for controlling the action of a blow molding machine of the type having a continuously extruding parison. The control means includes a photocell signal circuit responsive to extrusion of each parison at normal speed to initiate the decompression of a product at the blow molding station and opening and transfer of the mold halves back to the parison station. Should material in the extruder become depleted, the slower parison extrusion time will be detected and initiate signals for an alarm and deactivation of the blow molding machine. Means are also provided for disenabling this alarm and deactivation system if it is desired to "dry cycle" the machine for test purposes without running the extruder.