Patent ID: 8117715

Claim:
A caster, comprising: a base, to which a rotation shaft is mounted, the base forming a pivotal joint seat and defining a knob hole; wheels, which are rotatably mounted to the rotation shaft of the base, each of the wheels having an inside surface that is recessed to form an inner rim; a brake arm, which has a first end rotatably coupled to the pivotal joint seat of the base and a second end forming a brake pawl extending into the inner rims of the wheels, a spring being arranged between the brake arm and the base in such a way that the spring normally biases the brake pawl formed on the second end of the brake arm to depress against the inner rims of the wheels to brake the wheels; and a release knob, which is rotatably mounted in the knob hole of the base and comprises a cam section, which is positioned against the brake arm, whereby the cam section, when rotated by the release knob, drives the second end of the brake arm backward to release the brake pawl of the brake arm from the wheels so as to allow the wheels to freely rotate.