Abstract: A cleaning apparatus for a pool or tank has caterpillar tracks controlled by steering clutches actuated by a regulating device with a compass as a measured course value sensor, a setting device for the desired course value, a comparator for determining the error between the measured course value and the desired course value. The apparatus follows in oblique path from one travel path to the next by modifying the desired course by a given angle. After a given time, the desired course value is again modified by the same amount in the opposite direction, so that the cleaning apparatus returns parallel to the first path. By setting the angle and duration for the oblique travel, the new travel path can be selected independently of the dimensions of the pool to be cleaned.

Abstract: An apparatus or implement for underwater cleaning of swimming pool bottoms and/or walls having a chassis with traction drive and a suction pump mounted on the chassis. A suction nozzle is connected to the suction side of the pump, for drawing in settled particles. A filter is connected to the pressure side of the pump for catching the particles. A controlled diving cell which is floodable and clearable in a controlled manner is arranged on the chassis for varying the buoyancy of the apparatus sufficiently to raise and lower it in the water. A brush with a particular bristle configuration may be mounted in the suction nozzle.