"Transmission of documents via telephone wires is possible in principle, but the apparatus required is so expensive that it will never become a practical proposition."
|7571515||Drive system for a door or window and method of operating same|
A drive system for a moveable wing, especially for a door or a window, is described. The drive system includes at least one energy storage device by whose discharge of energy the wing is moved. The energy storage device is hereby controllable in its energy discharge...