US Patent 7263787 Laundry dryer with improved tumbler air flow passage openings

A laundry dryer having a tumbler with airflow openings of generally triangular shape with rounded transverse sides and opposed ends configured to permit passage of round heads of standard drywall screws when oriented parallel to the long dimension of the opening, while preventing the passage of standard collar buttons having a diameter no greater than the diameter of the drywall screw heads. Loose drywall screws within the tumbler are thereby permitted to pass harmlessly through the air flow openings in the rotating drum into the lint filter of the dryer without damage to the dryer nor interruption of the dryer operation.