Abstract: A system for curling turned-in lips about the open mouths of thin walled, stacked, thermoplastic containers, having brims which extend in a return direction axially, utilizes a plurality of externally helically grooved, tubular, thermally conductive, synchronously rotated rollers equiradially spaced from a common central axis to define an annular passageway between them through which a stack of the containers pass with the brim of the containers simultaneously engaged in the grooves of the rollers. While the brims are being heated radiantly and via conduction substantially to the critical forming temperature, the brims are engaged in the transport portions of the grooves, but the peripheral side wall portions of the container are not contacted.

Abstract: In differential pressure synthetic plastics thermoforming machinery, mold support assemblies mounted on a frame have relative movement between a mold open and a mold closed position. Power operated mechanism is provided for axially moving at least the female mold support assembly, and the female mold on the assembly which carries a stripper element mounted for relative movement with the mold. Mechanism is provided for automatically latching the stripper element to the frame as the female mold moves toward mold closed position, and abutments are provided on the mold support assembly and latch for automatically unlatching it only after the female mold has withdrawn a predetermined distance in its movement toward mold open position.