A description is given for a locking device of a ball-headed coupling for the releasable connection of a towing recovery tank to a tank to be towed away, a spherical cup being held on a drawbar of one tank and the locking device including a ball head being held on the other tank. In the connected condition of the coupling, a latching element engages over the spherical cup and holds it firmly on the ball head. The latching element is articulated about a transverse axis above the ball head to allow it to pivot into an uncoupled position and into a coupled position and is pivotably connected to a release lever pointing towards the ball head. This lever interacts with a locking lever pivotable about a longitudinal axis of rotation. <IMAGE>
