fig1 the window frame to the side of the window is inclined corresponding to the difference in the lengths of the one and opposite ends of the window the window 2 is narrower at one end thereof than at the opposite end thereof each window shade 5 has two support brackets or supports 6 at a top of the windshield the respective supports for each shade are spaced a distance apart a cylindrical hollow winding shaft 7 is supported between the support brackets at the narrower top in the drawings end of the window a window shade strip 8 is fastened by one non oblique edge to the periphery of the shaft 7 each winding shaft 7 has an internal thread 9 in a hollow interior thereof on one end an externally threaded spindle 10 carried on one of the support brackets 6 extends in the threaded interior of the shaft 7 the threads of the spindle 10 are complementary to the threads of the shaft 7 at its other end the winding shaft 7 is arranged like a journal bearing on a trunnion 11 by this support of the winding shaft 7 axial displacement of the winding shaft takes place automatically upon its rotary motion the path of displacement is determined by the thread pitch selected.