Patent ID: 8430731

Claim:
A device for controlling an airflow in a ventilation duct, comprising: a) a pivotable air flap which can assume adjustable opening positions and which prevents the airflow in the ventilation duct when in a closed position, b) a drive which is coupled to the air flap for pivoting the air flap, the drive being arranged on the inside of the ventilation duct, characterized in that c) a drive housing, which contains the drive, being suspended from a pivot bearing fastened to an inner wall of said ventilation duct, said drive housing being freely pivotable about a longitudinal mid plane of the ventilation duct, which is defined together with an apex line, in dependence of the pivot angle of the air flap in said ventilation duct, d) wherein the air flap has a curved elastic surface body which is supported under load in a stable position within the ventilation duct and contacts the ventilation duct in the open positions in two contact point regions, said contact point regions being arranged diametrically opposing each other with respect to an apex line of the surface body, and e) wherein the air flap rotates about the two contact point regions when rotated between the opening positions while the contact points act as points of rotation of the air flap.