When stylus A is moved along curve f(ϕ), link 1 slides in the guide of link 2 which turns about pole 0. At this, bent link 3 turns about pivot D and its pin a, connected by a turning pair to slider 4, moves alonkg the slot in link 5, turning lin 5 about pivot B. The number of revolutions of the measuring wheel is proportional to the integral u=c∫sqrt(r-r₀)dϕ where c = proportionality factor, ϕ = angle of rotation of link 1.
$1304$LG,MO$