The Chamberlain Group, Inc.

David J Miller

Mark D Siegler

James S Chang

A jack shaft garage door operator for opening and closing a movable garage door has a drive containing an electric motor. A rotatable jack shaft is connected to the drive unit to be driven thereby. A pull-up cable drum is connected to and driven by the jack shaft. A pull-up cable extends from the drum about which it is wound and connects to a bottom part of the garage door to raise the door. A pivoting arm is mounted near the jack shaft and provides tension to the cable. A shaft lock hub mounted on the jack shaft is engaged and locked by the arm if the tension in the cable drops. A stop is mounted on the garage door for engagement by the movable arm in the event that the door is opened without the cable being drawn in the cable drum.

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Arlington Heights, IL, United States of America

David J Miller