Patent ID: 7428954

Claim:
A damper for use in a drum type washing machine, the damper comprising: a cylinder; a piston partially inserted inside the cylinder in a movable manner, the piston comprising a guide portion, the guide portion having a diameter smaller than a remaining portion of the piston such that a radially protruding upper step portion and a radially protruding lower step portion are formed; a first damping member fixed around an inserted portion of the piston inside the cylinder so as to come into frictional contact with the cylinder, the first damping member located above the upper step portion of the piston; a second damping member fixed around the inserted portion of the piston inside the cylinder at a position spaced apart from the first damping member by a certain fixed axial distance and adapted to limit relative movement of the cylinder and the piston in a non-axial direction, the second damping member located below the lower step portion of the piston; and a movable damping member installed at the guide portion of the piston between the upper step portion and the lower step portion in an axially movable manner with respect to the piston such that the axial distance between the movable damping member and both the first damping member and the second damping member is not fixed, the movable damping member adapted to come into frictional contact with the cylinder whenever the movable damping member moves upward by the lower step portion of the piston during upward moving process of the piston and moves downward by the upper step portion of the piston during downward moving process of the piston, wherein each of the first damping member and the second damping member has a ring shape so that an inner peripheral surface of each of the first damping member and the second damping member is affixed to an outer peripheral surface of the piston, and wherein the first damping member and the second damping member generate a damping force when the piston moves inside the cylinder.