Wheel device and chair equipped with same

A chair comprising a seat portion, a leg portion and wheel devices mounted to a lower end of said leg portion;

• each of said wheel devices including a wheel having an axle, a holder member for holding said wheel, an urging member, arranged between said wheel and said holder member, for constantly urging said wheel to be projected in an operable position, and a retraction permitting member adapted to permit said wheel to be automatically retracted when a load sufficient to overcome the urging force of said urging member is exerted in the direction of gravity on a member on which said wheel is mounted, said retraction permitting member including a setting mechanism for setting said wheel to be in a retraction blocked state;
• wherein said wheel devices are set to be in an operating state under a no-load condition, and are selectively set to be in either a non-operating state or an operating state under the loaded condition;
• wherein the holder member includes a bearing that supports the axle of the wheel and a casing that supports the bearing;
• and
• wherein the setting mechanism is arranged within the casing and is operatively associated with the bearings so as to act on the bearing to set the wheel to be in the retraction blocked state.

A chair comprising a seat portion, a leg portion and wheel devices mounted to a lower end of said leg portion;

• each of said wheel devices including a wheel having an axle, a holder member for holding said wheel, an urging member, arranged between said wheel and said holder member, for constantly urging said wheel to be projected in an operable position, and a retraction permitting member adapted to permit said wheel to be automatically retracted when a load sufficient to overcome the urging force of said urging member is exerted in the direction of gravity on a member on which said wheel is mounted, said retraction permitting member including a setting mechanism for setting said wheel to be in a retraction blocked state;
• wherein said wheel devices are set to be in an operating state under a no-load condition, and are selectively set to be in either a non-operating state or an operating state under the loaded condition;
• and
• wherein said holder member is mounted in the form of a universal caster on the member on which the wheel is mounted.