1 The crankcoupler system is to be designed to drive the roc

1) The crank/coupler system is to be designed to drive the rocker as shown. If the coupler is to have a length of 15\'\', determine the crank length and the location of the crank center O2 with respect to the rocker center O4.

2) Design a linkage to carry the body in the figure through the two positions P1 and P2 at the angles shown. Use the follow choices: z = 1.075, phi = 204.4, beta2 = -27 degrees, gamma2 = -40 degrees, psi = 74 degrees, and s = 1.24

1. The crank coupler system is to be designed to drive the rocker as shown. If the coupler is to have a length of 15\", determine the crank length and the location of the crank center O2 with respect to the rocker center Os. 80 45 2. Design a linkage to carry the body in the figure through the two positions P1 and P2 at the angles shown. Use the following choices: z 1.075, 204.40, B -27o, -40, y 74, and 1.24. 1.236 147.5 2.138 210

Solution

solution:

1)for first question we can determine crank length and ground link length by knowing the two position of rocker as its extreme position from 45 degree to 80 degree

2)if we consider rocker is at 45 degree for crank angle to be 0 degree as from zero degree crank start rotating

and for 180 degree of crank rotation rocker will moveto extreme position and that is 80 degree.

3)synthesis by graphical approach has to carry out

1)first select pivot pointO4 and draw line of length equal to rocker length at 45 degree and mark first point as B1 and draw second line at 80 degree and at length equal rocker length mark another point B2.

3)from point B1 and B2 draw arc of radius equal to coupler length and find point of intersection to horizontal line from pivot point O4 and mark those point as A1 and A2.

4)distance between points A1 and A2 is equal to twice the crank length and center of this two point A1 and A2 is pivot O2.

5)from graphical method we get

length of O2O4=p=8\'\'

length of crank=O2A1=s=1.8\'\'

4) hence to perform rocker action for rocker link with full revolution of crank grashoff law should be followed and grashoffs law tells that

s+l<p+q

as here l=15 \'\' and q=10\'\',s=1.8\'\' and p=8\'\'

hence for given system we get that

s+l=1.8+15=16.8

p+q=8+10=18

hence here

16.8<18

s+l<p+q

hence given system will perform rocker movement for given length of crank and ground link

hence we get that

length of crank=s=1.8\'\'

ground link length=p=8\'\'