Flap valve for an exhaust gas turbo charger

The lock flap (1) has an operating arm (2) rotatably mounted in a bearing and a lock cover (3) is arranged at the side of the operating arm, which faces the bearing. The operating arm has an opening aligned tangential to rotating direction for receiving mandrels for backlash afflicted fastening of the lock cover on the operating arm. The lock cover has three raised contact points (6) on its side facing the operating arm. The contact points surround a gas force center of gravity position.