Patent ID: 7861833

Claim:
A damper for a washing machine, comprising: a cylinder, the cylinder including: a first end portion; and a second end portion having a tub fixing opening; a piston body, the piston body including: a first end portion inserted into the cylinder; and a second end portion having a case fixing opening; a first friction member disposed in a contact surface between the piston body and the cylinder; an extension bar inserted into the first end portion of the piston body, the extension bar including: one end portion coupled to the piston body; and the other end portion having a circumferential stopper, the other end portion of the extension bar extending such that the circumferential stopper is placed away from the first end portion of the piston body; a friction ring inserted into the cylinder, the friction ring having: a first end which is closer to the tub fixing opening; and a second end which is closer to the case fixing opening, the second end of the friction ring including a friction ring driving terminal, the friction ring driving terminal selectively contacting the circumferential stopper; and a second friction member formed on an outer circumferential surface of the friction ring to contact with an inner surface of the cylinder, wherein the circumferential stopper is disposed inside the friction ring and moves between the first end and the second end of the friction ring.