Patent ID: 8911171

Claim:
A spring attachment structure: adapted to fix an end portion of at least one spring for supporting a cushion of a seat to a seat frame of said seat, wherein said seat frame includes opposing seat frame sections, one of said opposing seat frame sections being formed from a round shaft, wherein: said at least one spring is stretched between said opposing seat frame sections; said end portion of said at least one spring is formed substantially in a U-shape in outline and comprises first and second spaced apart axial regions and an intermediate axial region interconnecting said first and second spaced apart axial regions; wherein said spring attachment structure comprises: a resin-made collar of a substantially U-shape in cross-section; and a metal-made retainer comprising: a body having a geometry of similar figure with said collar and having two edges; and at least one pair of first and second spring engagement pieces provided at both edges of said body; wherein: said first spring engagement piece extends downward from one of the both edges of said body and is bent laterally outwardly at a lower end thereof for engaging with said first axial region of said at least one spring at an engagement portion; said second spring engagement piece extends downward from the other of the both edges of said body and is bent laterally outwardly at a lower end thereof for engaging with said second axial region of said at least one spring at an engagement portion; said second spring engagement piece engagement portion is positioned higher than said first spring engagement piece engagement portion; said resin-made collar is adapted to be fitted over or mounted on said round shaft with an opening side thereof facing downward; said body of said retainer is adapted to be fitted over or mounted on said collar on said round shaft with said first spring engagement piece being located inside said seat frame and with said second spring engagement piece being located outside said seat frame; a distance between said second axial region engaged with said second spring engagement piece engagement portion and a lower end of a rear portion of said collar is less than a distance between said first axial region engaged with said first spring engagement piece engagement portion and a lower end of a front portion of said collar; a circumferential retaining-flange is provided around each of opposite end portions of said collar and has a surface that abuts an end-most edge of the retainer; and a reinforcing rib is formed outside in a longitudinal direction of each of said circumferential retaining-flanges, respectively.