Inzoka ebyiri ziyobora ninziga ninzoka ni ubwoko bwibikoresho bikoreshwa mugukwirakwiza amashanyarazi. Igizwe ninzoka, ikaba igizwe na screw isa na silindrike ifite amenyo yumutwe, hamwe ninziga yinyo, nigikoresho gifite amenyo ahuza ninyo.

Ijambo "kuyobora kabiri" bivuga ko inyo ifite amenyo abiri, cyangwa imigozi, izenguruka kuri silinderi ku mpande zitandukanye. Igishushanyo gitanga igipimo kinini cyibikoresho ugereranije ninzoka imwe, bivuze ko uruziga rwinzoka ruzunguruka inshuro nyinshi kuri revolution yinyo.

Ibyiza byo gukoresha inzoka ebyiri ziyobora ninziga yinyo nuko ishobora kugera ku gipimo kinini cyibikoresho mugushushanya, bigatuma bigira akamaro mubisabwa aho umwanya ari muto. Nukwifunga, bivuze ko inyo ishobora gufata uruziga rwinzoka mu mwanya udakeneye feri cyangwa ubundi buryo bwo gufunga.

Uburyo bubiri bwinzoka ninzoka zikoreshwa muburyo bwimashini nibikoresho nka sisitemu ya convoyeur, ibikoresho byo guterura, nibikoresho byimashini.