Patent ID: 7406745

Claim:
A wheel assembly comprising: a swiveling shaft at least including a swiveling sleeve, a pressing element disposed on the swiveling sleeve, and a first gear bracket and a second gear bracket located on an end of the pressing element; a support member movably assembled with the swiveling shaft, and at least including a rack with an opening, and a third gear bracket snapped in the opening, protuberances extending inwardly from opposing side walls of the opening; an arresting member mounted on the rack, a first resilient element being provided between the arresting member and the rack, an end of the arresting member corresponding to the pressing element and the third gear bracket, a second resilient element being provided between the arresting member and the third gear bracket; and wheels respectively pivoting to the rack and being limited at opposite sides of the arresting member, each wheel defining an annular groove in a surface thereof for corresponding to the arresting member.