Blow molding apparatus

Abstract

A reheat blow molding machine has an improved article handling system that carries heated preforms by a carriage assembly from an oven to a roller chain conveyor which moves them to a blow mold from when the blown product is moved to an eject station. The motions are linear and cyclical or periodic, drive means for such intermittent motions being provided. Preforms are handled in groups of four, each one being supported by its capping ring in a locating notch on the carriage and by the finish groove in a holder notch above it when it is transferred to the conveyor. All notches are open on the side facing the oven and have self-centering features to get and keep alignment for transfer and positioning at the blow mold. The carriage which moves preforms horizontally toward the conveyor and raises them to the elevation for transfer to the holder notches of the conveyor. Transfer happens when the carriage passes underneath the conveyor whereupon the holder notches of the conveyor engage the preform grooves and sweep or wipe the preforms out of the open side of the carriage notches. The conveyor roller chain moves linearly at right angles to the carriage path and delivers correctly aligned group of preforms to a corresponding group of blow molds. The chain is on its side, i.e. with pins vertical, the holder notches are supported by chain lugs outward of the chain on a leaf spring, and sliding bearing surfaces extend horizontally out from the chain to engage tracks which provide vertical support on the straight runs. At the blow station, the center rod passes through the stuffer cylinder rod and stuffer nose in a fluid-tight telescoping relation. At the ejection station, vertical guides provide position control over the product when the latter is pushed out of the conveyor holder notches whereby the product keeps a vertical alignment and falls away on a predetermined axis.