Patent ID: 8382209

Claim:
A rotary wheel cap, comprising: a fixed base which is fixed at a center of a wheel and includes an air suction portion and a first positioning portion, the air suction portion being driven by the fixed base and rotated with the wheel for sucking external air; a rotary cover which is installed axially at the fixed base and axially rotated with respect to the fixed base and includes a second positioning portion corresponding to the first positioning portion and a weight balancing portion; and an elastic member installed between the fixed base and the rotary cover to provide a returning force for the rotary cover to move against the fixed base; wherein the rotary cover is sucked by the air suction portion to compress the elastic member while the wheel is rotating, and the rotary cover is situated at a first position for forming a positioning relationship between the first and second positioning portions, so that the rotary cover is rotated with the wheel at the first position; and when the wheel is stationary, the rotary cover receives the returning force of the elastic member and is situated at a second position for forming a released relationship between the first and second positioning portions, so that the rotary cover is rotated with respect to the fixed base by the weight of the weight balancing portion at the second position.