Abstract: The invention concerns a control mechanism designed for manipulation with a stressing rod of a stressing unit which is used for fastening and prestressing of bolts, e.g. for flange joints of large pressure vessels, especially for flange joints of nuclear reactor vessels. The drive of the control mechanism of the stressing unit is a pseudo-planetary system of a gear mechanism which has the ability of both manual and mechanical control. A crown gear wheel is equipped with outer teeth and inner teeth. An inserted gear wheel of a driving pinion mates with the outer teeth. Only three planet gear wheels are inserted between the inner teeth of the crown gear wheel and the outer spur teeth of a central gear wheel. The central gear wheel is formed into the shape of a cylindrical shell which is bedded by its lower side, having a certain radial move possibility, on a wire bearing placed on a carrying body.

Abstract: An arrangement for cleaning components by a close ultrasonic field, particularly for cleaning of cylindrical filter inserts provides a strong ultrasonic field in a relatively small space enabling the cleaning of contaminations sticking to the filters. Means are provided for eliminating the influence of a varying strength of the ultrasonic field at different parts of an ultrasonic tool.

Abstract: An acoustic piezoelectric power transducer of sandwich shape with supply conductors pressed into grooves in the electrically conductive metal inserts and/or the piezoelectric plates.

Abstract: An ultrasonic cleaning arrangement particularly suitable for the cleaning of cylindrical filters to remove contaminations of medium sticking ability where the cleaned object is exposed to radiation of a close ultrasonic field while a liquid cleaning medium flows, in the course of cleaning, through the object to be cleaned.