Pactiv Corporation

John Gardner Fuller

Philip Stanley Baker

Kenneth James Simmons

Steven Robert Hogarth

A pair of form keys and a method for forming reverse drafts in foam parts are disclosed. A male form key is reciprocally mounted in a first mold half in a retracted position. A female form key is rotatably mounted in a second mold half in a neutral position. The first mold half includes a first drive pin that when engaged, moves the male form key into engagement with a foam sheet to form an undercut as the first and second mold halves are closed. The first mold half also includes a second drive pin that engages the female form key as the first and second mold halves close rotating the female form key into engagement with the foam sheet and the male form key. After closure of the mold and the product is formed, the mold is opened. As this occurs, the drive pins are disengaged and the male form key retracts and the female form key rotates to their neutral positions. The formed product may then be stripped from the mold while maintaining the reverse draft or undercut. In a further embodiment the male form key and the female form key are fluid actuated.

Method of forming a thermoformed foam part

Mold with fluid driven form keys

A pair of form keys and a method for forming reverse drafts in foam parts are disclosed. A male form key is reciprocally mounted in a first mold half in a retracted position. A female form key is rotatably mounted in a second mold half in a neutral position. The first mold half includes a first drive pin that when engaged, moves the male form key into engagement with a foam sheet to form an undercut as the first and second mold halves are closed. The first mold half also includes a second drive pin that engages the female form key as the first and second mold halves close rotating the female form key into engagement with the foam sheet and the male form key. After closure of the mold and the product is formed, the mold is opened. As this occurs, the drive pins are disengaged and the male form key retracts and the female form key rotates to their neutral positions. The formed product may then be stripped from the mold while maintaining the reverse draft or undercut.

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Canandaigua, NY, United States of America

John Gardner Fuller