US Patent 7063384 Flexible chair back

A flexible chair back provides a preferred elastic effect than conventional plastic chair backs, which comprises a back supporting board having a flexible member integrally extended from the back supporting board, a rear board and a spring sandwiched by the back supporting board and the rear board. The spring enhances the elasticity of the flexible member, so that the flexible member pushes a seated person's back quite adaptively, and therefore a person can sit against the chair back with comfort for a long period of time.