Chair having separable back

A chair comprising a seat plate and a back support extending upwardly at a rear portion of said seat plate to engage and support a back of a seat occupant, said back support including a waist support engaging and supporting a waist area of the back of the seat occupant and a shoulder support engaging and supporting a shoulder area of the seat occupant, said shoulder support being separate from and independent of said waist support, said shoulder support being located above and generally in alignment with said waist support, a waist support member supporting said waist support, a shoulder support member supporting said shoulder support, said waist support member extending forwardly under said seat plate and terminating in a forward end pivotally connected to said seat plate, said shoulder support member extending forwardly under said seat plate independently of said waist support member, said shoulder support member terminating in a forward end pivotally connected to said plate to enable independent pivotal movement of said support members, and an independent resilient structure connecting said seat plate to each of said support members, each independent resilient structure being independently adjustable to independently control the resilient resistance to pivotal movement of each of the support members, the waist support and the shoulder support.