CHOICE OF DRIVE SYSTEMS
Positive drive - The door curtain is driven positively when closing as well as opening, by means of a toothed driving wheel engaging in a side belt on the door curtain.
Low-friction drive - Doors have low-friction side guides for quiet operation. The door is opened by a conventional roller and closes under its own weight. The advantage of both drive systems is that there are no heavyweight elements, which makes the door safer and requiring less maintenance. A further advantage of the Positive drive is that it will operate smoothly under greater wind pressures than the Lowfriction.