Seat carrier for chairs

Claim 1

In a seat carrier for chairs, a base support fixed upright at a rear thereof to a vertical support leg, the base support having a front tip end in which a first end of a seat plate carrier is pivoted, bias means engaged with the base support and with the seat plate carrier urging the seat plate carrier upwardly of the base support, a back rest carrier pivoted at a front end thereof to a second opposite end of the seat plate carrier, cooperating intermeshing lamellar stack elements carried on the seat plate carrier and the back rest carrier and actuatable to lock the seat plate carrier to the back rest carrier, the back rest carrier being of an inverted U shaped cross section having a generally flat base piece and a pair of spaced apart legs extending downwardly from the base piece, the back rest carrier having a cross web depending downwardly from a forward end of the base piece between the spaced apart legs and fixedly secured thereto, and a plate spanning between lower rear parts of the back rest carrier legs and secured thereto, said cross web and plate defining with the back rest carrier base piece and legs, a box-like structure having enhanced, torsional rigidity.