FRAME STRUCTURE OF SEAT CUSHION

PROBLEM TO BE SOLVED: To make unnecessary a reinforcement member for welding a leg bracket by welding the leg bracket to a portion, from a corner to a support plate, of the front side of a main part of a seat cushion frame, and attaching a leg for rotatably supporting the seat cushion to the bracket. SOLUTION: A swing up seat comprises a seat cushion SC, a backrest SB to be folded forward over the seat cushion, with the front side of the cushion SC rotatably attached to an upper rail 6 by means of a leg 40. A hinge bracket 4 tightened to a leg bracket 3 to form a single member is rotatably pivoted to the leg 40 to hold the swung up state of the seat cushion SC by means of holding links 50, 51. Here, the leg plate 3 to welded to the area covering the front right or left corner 1A to a support plate 2 of a frame main part 1 to distribute loads working on the leg bracket 3 to the frame main part 1, 10 and the support plate 2 and prevent the leg bracelet 3 from deforming or separating.