Muviri unobvisa mvura unoumbwa ne screw axis ine ma plate ekugadzirisa nekufambisa akabatana, sezvo dhayamita yemukati ye screw axis yakakura kupfuura plate inofamba, plate inofamba inoita denderedzwa ne screw axis kudzivirira kuvharika. Nzvimbo iri pakati pema plate ekugadzirisa nekufambisa inova diki uye diki ichienda kunobuda madhaka. Mushure mekuwanda kwesimba regiravhiti, tsvina inotakurwa kuenda kunzvimbo dzine mvura, inobvisa mvura pasi pekumanikidzwa kwemukati kweplate yekubuda.