| 摘要 |
<p>The drive mechanism for a concertina-type door, including a motor and stepdown gearbox (1), a shaft (2) for winding up door-lifting belts (15), and an end-of-stroke unit (4), are mounted in a U-shaped metal channel section beam whose open side does not face downwardly and whose web is thus either the bottom horizontal portion of the beam, or else is disposed vertically. The beam (11) is fixed as a lintel at or near the top of door risers (12, 13), and is closed by a removable cover. The inside of the beam is lined with insulating material (16) and is equipped with a thermostatically controlled heater resistance. The beam housing enables the drive components to be maintained and repaired if need be without being removed from the door. It also enables a concertina-type door to operate safely in all weathers, and facilitates manufacture thereof.</p> |
