| 摘要 |
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. |
