Koehring Company

John Brown Inc.

Terrance L Brokoff

Albert W Arends

George L Pickard

Edward J Russell

Roland Karklin

Jerome E Froehlich

James R Greiner

A differential pressure thermoforming machine has a female mold with a female mold cavity, and an opposing mold, with a mold closing portion cooperable therewith. A foam injection head is perimetrally separated from the mold closing portion and is provided on the opposing mold. When the molds are initially closed, a differential pressure is created in the molds to cause the heated plastic sheet to move into contact with the mold cavity and form a configured pocket in the sheet. Mechanism is provided for releasing the plastic sheet from the carriage in which it has been moved between the molds, after the molding operation, to the cavity in the female mold, after which the molds are restored to spread-apart position. Mechanism is then activated to move the opposing mold to a position in which the foam injection head is now aligned with the female mold, whereupon the molds are again closed to bring the injection head into the pocket, whereupon the foam injection head is operated to charge a settable foam material to the pocket formed.

Differential pressure thermoforming and foam injection process and

Contact heater station mechanism for use in a thermoforming machine for particularly forming thermoplastic synthetic plastic and superplastic metal alloy sheets into shapes, such machines having a sheet transfer station, a heating station, and a forming station with relatively movable mold parts, and providing a circuit for sheet carrying carriages which index individually clamped sheets from one station to another cyclically in a path of travel. The mechanism includes platens mounted on the machine frame at the heating station to move toward and away from the path of travel of the carriages and sheets. A heater carrrier for elongate electrical resistance heaters carries a contactor plate, and is rigidly mounted to each platen in a manner to permit universal thermal expansion of the carrier and plate with respect to the platen. A motor is provided for moving each platen toward and away from a carriage indexed to the heating station to move the contactor plates into and out of heat transfer relationship with the sheet releasably clamped to the carriage.

Contact heater mechanisms for thermoforming machines

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Gladwin, MI, United States of America

Terrance L Brokoff