Patent ID: 7299665

Claim:
A drum-type washing machine having a lift installed on an inner circumferential surface of a drum, the lift comprising: a pair of inclined sides, disposed in opposition to each other to form a shape having a regular trapezoidal cross-section, configured to lift laundry; and a pair of friction plates, including a pair of opposing surfaces, respectively, provided on each of said pair of inclined sides and having a plurality of protuberances formed on both faces, to increase a frictional force with respect to the laundry, wherein the protuberances of said pair of friction plates are an array of projections each having a predetermined length, width, and height, and wherein the predetermined width and height of the projections vary with respect to proximity to the center of the drum, such that the width gradually decreases toward the center of the drum and the height gradually increases toward the center of the drum.