Locknut uye self-tightening nati zvakajairika kusungirira locknut. Ipurasitiki yakakosha yeinjiniya yakasungirirwa zvachose kune shinda, kuitira kuti tambo dzemukati nekunze mukusimbisa, ipurasitiki yeinjiniya inosvinwa uye inoburitsa simba rekuita rakasimba, richiwedzera kupesana pakati petambo dzemukati nekunze, zvichipa kupikisa zvachose kuzunguza.