Question

The Whithworth 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]

Answer 1

$cos\frac{\alpha }{2}=\frac{150}{300}=\frac{1}{2}$
$\Rightarrow$ $\frac{\alpha }{2}={60}^o$
$\alpha ={120}^o$
$\beta =({360}^o-{120}^o)={240}^0$
$QRR=\left(\frac{\beta }{\alpha }\right)=\frac{240}{120}=2$