Patent ID: 7441307

Claim:
A vacuum cleaning head comprising a housing, an agitator for agitating a floor surface, a chamber disposed in the housing for rotatably receiving the agitator, an opening formed in a portion of the chamber adjacent the agitator facing a floor surface, an air turbine driving the agitator, an air inlet in the housing admitting clean air to drive the turbine, and a restricting device arranged in a discharge outlet from the chamber, the restricting device comprising a guide vane projecting outwardly from a wall of the discharge outlet, the guide vane being configured to restrict a cross-section of the discharge outlet in a restrictive position, the guide vane being configured to be resiliently movable with respect to the wall of the discharge outlet to an open position in response to a flow of debris past the restricting device to restrict the cross-section of the discharge outlet to a lesser extent, the restricting device being further configured to return to the restrictive position after the passage of said debris.