Seat backrest with adjustable lumbar supporter

摘要

Herein disclosed is a seat backrest with an adjustable lumbar supporter which comprises a rod transversely crossing frame members of the seatback to be rotatable about the axis thereof relative to the frame members, an arm member secured to the rod, a support member pivotally connected to the arm member, lumbar pressing means such as spring connected to the support member, first control means for permitting the support member to rotate about its pivoted portion relative to the arm member when operated, and second control means for permitting the arm member and thus the rod to rotate about the axis of the rod relative to the frame members when operated.