teoreetiline hammaslatt, mille profiil ja parameetrid on standardiseeritud ja mis võetakse hammasrataste hambaprofiilide kujundamise ja ülekande geomeetrilise arvutuse aluseks, rack, which teeth are used as a basis for defining the standard tooth dimensions, guaranteeing the standard parameters of gear tooth profile and causing mating gears to be correctly meshed with this standard basic rack as teeth of both pinion and wheel have conjugate profiles, and as a result preserving a constant transmission ratio