Hi! It is necessary to construct two circles and connect them with lines. The key is to constrain "tangent" between the segments and the circles. The file is attached. The construction of the tree you can see and change settings. Good luck!
This file Inventor 2015. If you have any version below, can not be read. Unfortunately I can not translate into a lower version.
IPT file updated. I add a picture, which shows the construction of the tree. I have a Russian interface, but I think you will understand.
Hello Eugeny, thanks for the response but I always model exactly as your image shows, but the motion between cam and lifter always stays on the diameter of the lobe. I need the lifter to follow complete outer contour of the cam. Also for some reason the ipt you sent had an error, maybe I'm missing something, can you please resent it. Thank you