| 摘要 |
<p>A door operating mechanism intended for "up and over" garage doors of the "canopy" type in which the door moves from a vertical, closed position to an upper, horizontal, open position is provided with a special drive arrangement to make the operation smoother. Vertical guides (11) locate rollers (12) at the sides of the door. An elongate power transmission element (dashed line) extends generally parallel to the guide (11) and the transmission element is connected by a link (25) to the door (10). At the initial stage of opening the door the link is at an acute angle to the plane of the door when the door is vertical and the acute angle decreases as the door moves towards the horizontal position. This imparts a horizontal component of movement to the door as it moves from the vertical followed by a primarily vertical movement of the door.</p> |
