A cam is a mechanical device used to drive a follower on a specified motion. Using links can be combined into a mechanism driven by a cam to produce the motion desired. Thus translating the motion of the element on a mechanism until the path of the main follower that brings the motion of the cam to that element is traced or identified, the design of the cam can now be identified.
1. Trace the path of the cam follower using given information such as the motion of an element or the follower itself.
2. Identify the rotation of the cam.
3. Using the traced motion of the follower from the link, match it with the corresponding angular displacement of the cam as given by the design or problem. If the cam will rotate clockwise, the matching will be done counter clockwise and if rotates counterclockwise do otherwise. This is because that if the cam is held stationary, the relative motion of the follower is opposite in direction.
Soon, you'll be able to identify the landing points of the tip of the follower on the cam which will create your cam profile. This is done by tracing the points using french curves or bending rulers. It is necessary to imagine the displacement of the follower to determine a more accurate cam profile. There will be times that compass will be used to draw a profile curve of a cam.
It will be advised that always translate the traced path of the follower on an axis that is intersecting the center of the cam because this will help you to understand the profile of the cam in a better way as given on the problem.
If you like to have an example from Machine Elements by Doughtie, I'll try to do it or upload if already made that problem within a week. Just leave a comment.
