Question

kinematic design of machinery

Problem #4. Considering the drag link quick-return mechanism shown below, show the linkage in its limiting positions (corresponding to extreme positions of the slider). Measure the angle through which the crank link 2 turns as the slider moves from extreme left to extreme right. Compare this with the corresponding angle as the slider moves to the left. Find the stroke of the slider (distance between limiting positions) and the time ratio of advance to return. Find average piston velocity in each direction between limiting positions, if the crank rotates clockwise at 100 rpm. Let O2O4= 3 in. 1 1 18- in. Show your OzA 4in, AB =5- in., BC 8- in., O4B 6 in., O4C = 6 in., and CD 2 2 2 solution graphically, use a scale of 4 in 12 in 4 O2 3

Answer 1

B 12.50 A 04 02 118.25 C D A C 04 02 R 24.50 8.80이
$\theta_1 = 118.25$

U=8.8

left-right 01

left-right 118.25 8.8 127.05

$\theta_{right-left} = 360^0-(\theta_1+\theta_2)$

$\theta_{right-left} = 360 - 127.05^0 = 232.95^0$

$Time\;Ratio:TR=\frac{232.95}{127.05}$

$TR=1.8335$

Stroke:

At right most position

At left most position

Average Piston velocity:

$w = 2*\pi*100/60 = 10.47rad/s$

Vavg,le ft-right Stroke

$v_{avg,left-right} = 12*\frac{10.47}{127.05*(\pi/180)}$

$v_{avg,right-left} = Stroke*\frac{w}{\theta}$

$v_{avg,right-left} = 12*\frac{10.47}{232.95*(\pi/180)}$

Vavg.right-left 30.902in/s
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