Abstract: A side-hinged, 180 degrees rotatable window, having a window casement which is pivotably mounted about a first vertical axis and about a second vertical axis relative to a window frame. The window casement is supported hanging at its one upper corner via a head portion (27) on a pivot pin (26) in a carriage (25), which is displaceable in a horizontal guide (16) in the window frame. The window casement is pivotably mounted at its center axis at the one end of an upper and a lower support or pivot arm, the opposite end of which is pivotably mounted about a third vertical axis in the window frame. The carriage (25) is designed with a part-spherical seat (25') for an equivalent part spherical portion of the support head (27) of the first pivot pin.

Abstract: A flat web-shaped blank is formed with a pair of parallel recesses, each of which defines an angle of less than 90.degree. to permit the faces of the recess to press against each other when the side sections of the blank are pivoted into a U-shape. The pressing of the lateral faces of the recess against each other serves to bias the side sections away from each other. The flat blank can be wound in a coil for storage and transportation purposes. The blank can be readily shaped into a U-shaped guide rail and inserted into the groove of an associated window frame portion. Shoulders on the outside of the side sections of the blank can snap fit into grooves in the walls of the groove of the window frame portion.