Phillips Petroleum Company

Irvin L Sumpter

Donald L Peters

John R Rathman

In blow molding an article with a reverse fold, a profiled bar is positioned where the parting line of the mold is to be when the mold is closed. The bar provides a reverse fold in the plastic article during a pre-blow step. In operation, a pre-pinched parison is formed adjacent the bar and as the mold begins to close a small amount of pre-blow air is introduced into the parison folding it against and over the bar. After the mold is closed, blow air is introduced to form the part. A complex part with good wall distribution of material can be obtained by this method.

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Bartlesville, OK, United States of America

Irvin L Sumpter