Abstract: A hydraulic displacement machine that can operate as a pump or a motor in connection with an electrorheologic or magnetorheologic fluid includes a housing, a rotary piston arranged to rotate within a chamber in the housing, at least one displacement vane provided on the rotary piston, a plurality of field generating elements such as capacitor plate segments and/or coil arrangements that are each individually electrically energizable and that are arranged on the two sidewalls of the housing chamber distributed around the circumferential direction, and an actuator connected to each field generating element so as to move the elements of each pair selectively closer together and farther apart from each other. By applying an appropriate electric or magnetic field to the electrorheologic or magnetorheologic fluid between the field generating elements, the fluid is locally solidified in the "flow mode" to form a stationary seal plug within each fluid chamber between respective consecutive vanes.

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: A tapering flow duct is formed below a chassis having a caterpillar track and forms lateral openings between a cleaning brush and the tracks. The flow duct is connected through an opening to a suction duct of a suction pump which conveys the sucked up liquids with the contaminants contained therein into a filter. Due to the increased flow velocity, the static pressure in the flow duct is reduced, so that the chassis is pressed onto the bottom surface and can overcome severe gradients without sliding.

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.

Abstract: Analog signals representing the unbalance of a rotor in one or more planes extending perpendicularly and across the longitudinal rotational axis of said rotor, are first adapted prior to an analog to digital conversion. The adaptation takes place in response to at least one adaptation value, which is characteristic for the balancing, such as an attenuation, a sensitivity control, an rpm or measuring range selection and the like. The adapted signal is then combined with a reference signal having a frequency corresponding to the rpm of the rotor. The combined signal is subjected to an analog to digital conversion and then digitally displayed. The circuit arrangement for the performance of the signal adaptation, signal combination and signal display includes adaptation circuit means which are responsive to said adaptation value or values. The adaptation circuit means is connected to receive the unbalance information with the correct sign (+ or -).