Mkono wa rocker m'galimoto kwenikweni ndi lever yokhala ndi zida ziwiri yomwe imayendetsanso mphamvu kuchokera ku ndodo yokankhira ndikuchita kumapeto kwa ndodo ya valve kukankhira valavu.Chiŵerengero cha kutalika kwa mkono kumbali zonse za rocker mkono chimatchedwa rocker arm ratio, yomwe ili pafupi 1.2 ~ 1.8.Mbali imodzi ya mkono wautali imagwiritsidwa ntchito kukankhira valve.Malo ogwirira ntchito a mutu wa rocker arm nthawi zambiri amapangidwa ndi mawonekedwe a cylindrical.Pamene mkono wa rocker ukugwedezeka, ukhoza kugubuduza kumapeto kwa ndodo ya valve, kotero kuti mphamvu pakati pa ziwirizi imagwira ntchito motsatira valavu momwe zingathere.Mbali ya rocker imakumbidwanso ndi mabowo opaka mafuta ndi mafuta.Zomangira zosinthira kuti zitheke kutulutsa valavu zimayikidwa mu dzenje la ulusi kumapeto kwa mkono wa rocker.Mpira wamutu wa screw umalumikizana ndi tiyi wa concave pamwamba pa ndodo yokankha.
Nkhono ya rocker ilibe kanthu yomwe imayikidwa pamtundu wa rocker arm kupyola pa rocker arm bushing, ndipo yotsirizirayo imathandizidwa pampando wa rocker arm shaft, ndipo mkono wa rocker umabowoleredwa ndi mabowo amafuta.
Mkono wa rocker umasintha njira ya mphamvu kuchokera ku ndodo yokankhira ndikutsegula valavu.