Patent ID: 8790468

Claim:
An apparatus for cleaning an upright surface of a structure comprising: a carriage adapted to be moved in upward and downward directions relative to an upright surface of a structure, a cleaning element rotatably mounted on the carriage for rotation about a generally horizontal axis, said cleaning element having members with outer end portions that contact a surface area of the upright surface horizontally aligned with the axis of rotation of the cleaning element for cleaning said surface area of the upright surface, a thruster mounted on the carriage operable to produce a thrust force that is perpendicular to the surface area being cleaned and horizontally aligned with said surface area and to maintain the outer end portions of the cleaning element in contact with the surface area of the upright surface of the structure during cleaning thereof, said thruster is a fan having a horizontal axis of rotation horizontally aligned with the horizontal axis of rotation of the cleaning element, and a motor operable to rotate the fan to produce the thrust force that is perpendicular to the surface area being cleaned.