Qhov no tshuab qauv qauv peb cov menyuam symmetrical hom, cov menyuam nyob rau hauv ob central symmetricalTxoj hauj lwm nyob rau hauv cov menyuam txav vertically los ntawm cov ntsia hlau worm thiab txhob lo lo ntxhuav niam, Ob sab qisRollers rotates los ntawm cov iav reducer tso zis thiab qis dua cov menyuam Gear mesh, muab lub zog rauDaim ntawv yob. Lub tshuab tsis zoo yog qhov kawg phaj dabtsi yog khoov yuav tsum tau siv lwm yam khoom siv.