making the necessary adjustments to keep such down pressure consistent the present invention is directed to a totally different concept in brush construction and a concept which eliminates the need to have a mechanism for raising and lowering the brush to vary the aggressiveness of the cleaning operation or brush down pressure instead of having bristles which extend generally perpendicularly to the surface of the cylindrical brush driver tube the bristles are attached so that they extend along the surface of the driver tube when the brush is at rest the angle between the bristle and the driver tube surface is closer to parallel with that surface than it is to perpendicular normally the angle will be less than 30 degrees an angle that has been found to be satisfactory although the invention should not be so limited is to have each bristle make an angle of approximately 12 degrees with the cylindrical surface of the brush driver tube the bristles should be formed of a material for example a suitable plastic or elastomer which allows the bristles to flex outwardly as the brush rotates with the degree of outward extension being determined by the rotary speed of the cylindrical driver tube the bristle material should be such that it has.