Question

A four bar mechanism is made up of links of length 100, 200, 300 and 350mm. If the 350 mm link is fixed, the number of links that can rotate fully is .

Answer 1

$s=100,p=200,l=350,q=300$
$(s+l)=350+100=450<(p+q)$
$450<200+300$
$450<500$
Grashof law is satisfied.
350 mm link is fixed.
Then, shortest link (=100 mm) is adjacent to fixed link, so it will give crank only.

POINT TO REMEMBER

• Accoding to Grashof's law, for continuous relative motion $s+l\le p+q$ So, in this problem, s + l < p + q is satisfied
• If shortest link, s is fixed, mechanism will be double crank.
• If link adjacent of shortest link is fixed, mechanism will be crank-rocker type.