SEAT BACK FRAME MADE OF LIGHT ALLOY

PROBLEM TO BE SOLVED: To form a seat back frame so as to prevent possible break through by a reinforcement rib at a side flange part without increasing the weight of a whole frame and disturbing the attaching of a cushion pad or the like. SOLUTION: A base body has an outer frame 1 which has each frame side 1a made up of a back flange part 10 and the side flange part 11 rising from the back flange part 10 in an L-shaped cross section while forming the whole of the frame in almost a quadrilateral and the reinforcement rib 40 is installed at a specified frame portion running across the width of the quadrilateral with both ends thereof across the internal surface side of the side flange part 11. The reinforcement rib 40 is so arranged as to make faces 40a(40b) of both ends thereof crossing the internal surface side of the side flange part 11 lower than the rise of the side flange part 11 and is made to rise aslant almost to the rising end of the side flange part 11 from a general part 40c thereof across the width of the quadrilateral. COPYRIGHT: (C)2004,JPO