Question

The flywheel of a hand operated chaff cutter with 4 cutting knives is rotated at 60 rpm and is connected to worm gear assembly for rotating feed rollers. The number of teeth and threads of worm gear and worm are 20 and 2 respectively. What would be the chaff length? (Diameter of feed roller is 15 cm)

(a) 12.78 mm

(b) 31.26 mm

(c) 14.98 mm

(d) 11.78 mm

I got this question during an online exam.

I would like to ask this question from Processing Equipments in chapter Processing Equipments of Farm Machinery

Answer 1

The correct answer is (d) 11.78 mm

The explanation: Explanation: \(\frac{Nflywheel}{Nfeed \, roller}=\frac{Nworm}{Nworm \, gear}=\frac{Tworm \, gear}{Tflywheel} \)

\(\frac{60}{Nr}=\frac{20}{2} \)

Nr = \(\frac{60*2}{20}\) = 6 rev/min

L*n*Nf = π*0.15*6

L = \(\frac{π*0.15*6}{4*60}\) = 11.78 mm.