Upholstered seat assembly and a one-piece seat and back shell of molded plastic therefor

A one-piece seat and back shell molded of thin-walled propylene copolymer plastic of high impact resistance and toughness for an upholstered seat, said shell having a seat and an upwardly extending back, a continuous edge flange formed integrally with and around said seat and back and extending generally normally to said seat and back, said edge providing means for attachment of a cushion, said back and seat having inwardly curved side walls forming a recession therein for the reception and support of a cushion,

• said seat having a plurality of generally parallel curvilinear slots which demarcate a plurality of generally parallel curvilinear spring segments extending transversely across said seat, said seat being sloped to have a positive bow for said segments whereby said segments deflect downwardly in response to a load created by the occupant of the upholstered seat,
• said seat also having an underside, and a generally rectangular frame extending downwardly from said underside and formed integrally on said seat underside and located within and spaced inwardly from said edge flange around said seat, and means adjacent the corners of said frame providing a mounting surface for said shell.