GATE 2021 ME (ME1) – Question 62
The Whitworth quick return mechanism is shown in the figure with link lengths as follows: OP = 300 mm, OA = 150 mm, AR = 160 mm, RS = 450 mm. The quick return ratio for the mechanism is _____ (round off to one decimal place).
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Correct answer: 1.99 to 2.01
Explanation
This is the Whitworth geometry with the fixed-centre separation OA smaller than crank OP. The limiting crank angles use $\alpha=\sin^{-1}(OA/OP)=30^\circ$.
Working and return crank rotations are 180+2α=240° and 180−2α=120°. At uniform speed their time ratio is **240/120=2.0**.