CHAIR HAVING BACKREST WITH AUXILIARY SUPPORT WAIST WHICH IS PROJECTED AND ROTATED IN STATE HAVING ELASTIC FORCE WITHOUT HORIZONTAL GRAVITY BECAUSE OF SPRING ELASTICITY

摘要

PURPOSE: A chair having a backrest with an auxiliary waist support which is projected and rotated in the state having an elastic force without horizontal gravity because of a spring elasticity, is provided to allow a user to conveniently sit on the chair by always supporting his/her waist with aid of the auxiliary waist support. CONSTITUTION: The chair having a backrest with an auxiliary waist support includes: a backrest support(10); an insertion recess(11), arranged in the center of the backrest support(10) to be inserted by a height regulating bar(42) and having a bolt fixture(17); a spring supporting plate(14), arranged in the lower center of the backrest support(10) and supporting a spring holder; a bolt penetration ring(15), arranged respectively on both sides of the spring supporting plate(14); a connection plate(20) of the auxiliary waist support(30); an elastic spring(24), arranged on the outer circumference of a connection tube(22) on the upper portion of the connection plate(20); a spring insertion hole(25), arranged on the connection plate(20); and a swivelling bolt hole(21).