of the movable arm 56 is located below the grip 53 the spring element 1 embodied as a leaf spring in the prestressed installation position is braced firmly on the housing 41 by its fixed arm 55 on the first bearing point 5 the movable arm 56 is movable with its end embodied with a right angle bend 61 along the guide rib 53 and rests tangentially on the adjusting screw 54 for determining the emergency air position the driver embodied on the toothed segment 42 and meshing with the bearing point 24 of the movable arm 56 travels over a shorter radius compared to the bent part of the movable arm 56 of the spring element 1 in the form of a leaf spring it is assured as a result that the driver 57 coming from the direction of maximal opening lifts the movable arm 56 inward radially away from the guide rib 53 in the further motion out of the emergency air position in the direction of a minimal opening of the throttle valve the movable arm 56 accordingly does not rub along the guide rib 53 the guide rib 53 is embodied as an arc that is concentric with the throttle valve shaft because of this the movable arm 56 of the spring element 1 may have an adjusting range of u00b1 1 5 mm in every position of the adjusting screw 54 for determining the emergency air position moreover this always assures the same radial spacing from the center of rotation as a result.