OVERHEAD DOOR WITH DUAL TRACK MOUNTING

摘要

An overhead door, which is adapted to have its primary tracking members temporarily disengaged from their primary track when impacted by a substantial force when in the closed or partially closed position, is adapted to smoothly transition from its vertical, closed position to a non-vertical, open position by the use of second tracking members and track which come into use as the door panels transition from a vertical orientation to a non-vertical orientation. The impact caused disengagement feature is therefore effective without interference from the second tracking members, but progressively gives way to the second tracking members and track as the door is raised toward an open position.