US Patent 7631394 Suction brush for vacuum cleaner

A suction brush for a vacuum cleaner is provided. The suction brush includes an upper casing; a lower casing; an elevating plate installed between the upper casing and the lower casing; a cleaned surface sensing part for sensing; a lever rotatably provided around a rotating shaft that is parallel to the elevating plate; and a solenoid. The solenoid rotates the lever in one direction when the surface to be cleaned is the hard floor and rotates the lever in the other direction when the surface to be cleaned is the carpet. The lower casing contacts the surface to be cleaned as the elevating plate descends, while it comes apart from the surface to be cleaned as the elevating plate ascends.