Rotary blow molding machine with movable clamp assemblies and method

A continuous rotary blow molding machine including a main frame, a mold close cam on the main frame;

• a rotary frame on the main frame;
• the rotary frame having an axis of rotation;
• a motor for rotating the rotary frame around the axis of rotation at a constant speed;
• a plurality of mold clamp assemblies mounted on and spaced around the rotary frame, each mold clamp assembly including a blow mold having two opposed mold halves movable toward and away from each other in a direction parallel to the axis of rotation, the mold halves defining a mold cavity when the mold is closed, a mold close cam follower engaging the mold close cam, and a mechanical connection between the mold close cam follower and each mold half whereby shifting of the mold close cam follower by the mold close cam closes the mold;
• a flow head to extrude a first continuous parison downstream for capture by successive molds as the molds are rotated downstream and past the flow head;
• and an upstream mold-shift mechanism for each mold clamp assembly, wherein each upstream mold-shift mechanism shifts a mold in an upstream direction on the rotary frame after the rotary frame rotates the mold in the assembly in a downstream direction over the parison and the mold actuation cam follower closes the mold on the parison to position the closed mold adjacent to the next upstream mold and reduce flash between the molds.