Tiltable chair

A tiltable chair comprising:

• a fixing base having a tiltable housing disposed on an upward protruding dome-shaped center thereof in such a manner as to be movable in an arbitrary direction;
• a gas cylinder disposed inside the tiltable housing in such a manner as to be linearly reciprocated in upward and downward directions;
• a seat plate disposed on top of the gas cylinder;
• and
• an elastic tiltable member disposed inside the fixing base in such a manner as to accommodate a longitudinal lower part of the gas cylinder therein to allow the gas cylinder to move tiltably about vertical axis to the bottom of the fixing base,
• wherein the elastic tiltable member comprises a fixed frame located on the bottom of the fixing base, a coupling frame located inside the center portion of the fixed frame to accommodate the gas cylinder therein, and a rubber packing located between the fixed frame and the coupling frame and deformed elastically in every direction,
• wherein the rubber packing has tilt concave grooves formed inward to a given depth from top and underside respectively in such a manner that the tilt concave grooves are reduced in width toward the insides thereof to thus form inclined surfaces,
• wherein the rubber packing has first waveform coupling portions in which crests and roots are repeatedly formed on an inner peripheral surface of the rubber packing and a coupling groove concavely formed inward to a given depth from an outer peripheral surface of the rubber packing, the coupling frame has second waveform coupling portions formed on an outer peripheral surface of the coupling frame in such a manner as to correspond to the first waveform coupling portions, and the fixed frame has a coupling protrusion corresponding to the coupling groove.