Selective closure device for window opening of building, has guiding unit for guiding movement of sliding panel, where guiding unit includes additional roller to cooperate with lower guide rail when panel is removed from opening

摘要

The device has a guiding unit for guiding a sliding panel between closed and open positions. The guiding unit includes an upper rail (12) anchored above an opening and engaging a guide shoe of the panel. An upper roller (14) is anchored to collaborate with an upper guide rail. A lower roller (15) is anchored under the upper roller to collaborate with a lower guide rail. An additional roller (19) is anchored on the same horizontal line as the lower roller at a distance equal to half the width of the panel, to cooperate with the lower guide rail when the panel is removed from the opening.