Abstract: A counterbalanced window operator includes a housing in which a rotatable lead screw, rotated by a crank handle or electric power unit, cooperates with a non-rotatable nut member to axially displace the nut member and move pivoting arms to open and close the window.

Abstract: A Venetian blind for inside installation in a window in an inclined roof comprises profile lists fastened to the side pieces of the sash for guiding at least the lower list of the shade, whereby a load acting on the lower list of the Venetian blind to pull it towards its lowered position, is provided by at least one coil spring. The coiled part of the spring is seated in a housing at one end of the lower list with its axis of rotation essentially parallel to the longitudinal axis of the lower list, and the uncoiled part runs in one of the profile lists and is fastened at the lower end of this list near the lower edge of the window.

Abstract: In a hinge device for inclined tiltable windows with external overlapping cover rails, the base plate of the main frame supports through a pair of pivotable links an intermediate member which is movable in a parallelogramlike--or pantographlike--manner and itself carries a pivot pin on which the sash base plate of the hinge device is journalled. The rotation of said base plate about the pivot pin is co-ordinated with the movement of the intermediate member by way of a coupling link that through pivot pins is connected with the sash base plate and the pivotable link adjacent the coupling link, respectively. The coupling link makes it possible in a simple and cheap manner to reliably controlling the hing parts during the full tilting of the sash in both directions.

Abstract: In a window, especially for installation in an inclined roof, a secondary frame element or sash is connected with the stationary main frame of the window in a top hinge and is urged in its opening direction by a lifting lever hinged at its one end through a pivot pin to a side member of the secondary frame element or the main frame, while its other end is pivotally and displaceably connected with the adjacent member of the main frame or the secondary frame element, respectively, said lever being biassed by a spring tending to displace said other end in a direction corresponding to opening the window.The said other end of the lever is provided with several pins which during the opening or closing movement of the window successively become operative as the pivot point, thereby giving the lever a varying effective length, whereby the curve of the spring balancing moment performed on the frame element may be optimized and, if desired, a series of stable positions of rest for the tilting frame may be obtained.