Ingalo yerocker emotweni eneneni sisileva esixhobe-mbini esibuyisela amandla ukusuka kwintonga yokutyhala kwaye sisebenze ekupheleni kwentonga yevalve ukutyhala ivalve ivuleke. Umlinganiselo wobude bengalo kumacala omabini engalo yerocker ubizwa ngokuba yi-rocker arm ratio, emalunga ne-1.2~1.8. Esinye isiphelo sengalo ende sisetyenziselwa ukutyhala ivalve. Umphezulu osebenzayo wentloko yengalo ye-rocker ngokuqhelekileyo yenziwe nge-cylindrical shape. Xa ingalo yerocker ijinga, inokuqengqeleka ecaleni kobuso bentonga yevalve, ukuze amandla phakathi kwezi zimbini asebenze ecaleni kwe-axis yevalvu kangangoko kunokwenzeka. Ingalo yerocker nayo yombiwa ngeoyile yokuthambisa kunye nemingxuma yeoli. Isikrufu sokulungelelanisa ukucocwa kwevalve sifakwa kumngxuma ophothiweyo kwincam yengalo emfutshane yengalo yerocker. Ibhola yentloko ye-screw idibene ne-concave tee phezulu kwintonga yokutyhala.
Ingalo yerocker ayinanto iseti kwi-rocker arm shaft kwi-rocker arm bushing, kwaye le yokugqibela ixhaswa kwisihlalo se-rocker arm shaft, kwaye ingalo ye-rocker yombiwa ngemingxunya yeoli.
Ingalo yerocker itshintsha icala lamandla ukusuka kwintonga yokutyhala kwaye ivule ivalve.
