problems

Solution:
First draw the displacement schedule to scale, and divide the cam into 12 equal sections. The cam is
rotating in the clockwise direction so that the cam is layed out in the counterclockwise direction.
Then draw the locations of the follower. The cam profile is then drawn such that the cam is tangent
to the follower in the different positions. The cam is drawn as follows:
Problem 8.19
5
4
6
7
8
- 363 -
3
2
1
12
11
9 10
Lay out a cam profile using a harmonic follower displacement (both rise and return). Assume that
the cam is to dwell at zero lift for the first 100˚ of the motion cycle and to dwell at a 1 in lift for cam
angles from 160˚ to 210˚. The cam is to have a translating, radial, roller follower with a 1-in roller
diameter, and the base circle radius is to be 1.5 in. The cam will rotate clockwise. Lay out the cam
profile using 20˚ plotting intervals.
Solution:
The displacement profile can be easily computed using the equations in Chapter 8 in a spreadsheet
or MATLAB program. The profile equations are:
For 0 100˚
y=0
For 100˚ 160˚
y = L
1 cos
2
where L = 1, = 100˚, and =160˚100˚= 60˚.
For 160˚ 210˚
y=1