Patent ID: 7836937

Claim:
An automatic tilting mechanism for a window shade, comprising: a rotator rail mounted for rotation in a first direction and in a second direction about a first axis of rotation; a spring also mounted for rotation in said first direction and in said second direction about said first axis of rotation, said spring defining a first end which is fixed relative to said first axis of rotation and defining a second end which rotates in said first direction and in said second direction about said first axis of rotation and means for connecting said spring to said rotator rail such that said spring winds up when said rotator rail rotates in said first direction and said spring unwinds when said rotator rail rotates in said second direction; a first shaft which defines said first axis of rotation; an end cap defining an inside surface and wherein said first shaft projects substantially perpendicularly from said inside surface of said end cap; means for shifting said first shaft relative to said inside surface of said end cap in a direction which is substantially parallel to said inside surface of said end cap, said means for shifting including a skew adjustment screw acting inside a cylindrical cavity formed when said first shaft slidably interlocks with said inside surface of said end cap; a front ladder tape and a rear ladder tape and a plurality of slats suspended from said front and rear ladder tapes, wherein said rotator rail defines a cylinder with an outside circumference, said front ladder tape is attached to said outside circumference at a first location and said rear ladder tape is attached to said outside circumference at a second location; and wherein said ladder tapes and said slats wind up onto said rotator rail when said rotator rail rotates in said first direction and said ladder tapes and said slats unwind from said rotator rail when said rotator rail rotates in said second direction; and wherein when one of said front and rear ladder tapes is fully unwound from said rotator rail, said spring urges said rotator rail to rotate in said second direction such that said other of said front and rear ladder tapes is fully unwound from said rotator rail.