Buenos Dias Peter,
If I am picturing the mechanism correctly I think cam is the right choice.
However,
it sounds as if you will need to check the "enable liftoff" option within
the cam
so that the pin is not "glued" to the dog.
If I am way off base here just post a picture or the model geometry.
Hope this helps,
Steve
Stephen Seymour, P.E.
Principal Engineer
Seymour Engineering & Consulting Group, LLC
www.seymourecg.com