.~ Back and bottom adjust in a fixed relationship {4}
302.3
.~.~ Torsion bar or torsion spring
DEFINITION
Classification: 297/302.3
Torsion bar or torsion spring:
(under subclass 302.1) Opposed back movement wherein the resilient member is a solid material considerably longer than it is wide, or is a corkscrew-type that twists to resist the tilting of the back.