Sorry, Brent- I typically make this sort of thing on the fly. I would definitely use a gearhead for the motor, because otherwise you will have very little torque to deal with. So there are no real "drawings" of any sort to work from. But I can point out a mechanism for you to learn from. Ever see a wheel with a shaft sticking out, off-center? Now, attach an arm to that shaft and as the wheel turns, the arm can reciprocate. Picture the mechanism on an old style steam locomotive that turns the wheels. Windshield wipers have similar mechanisms, or they have a wheel with a slot inside. This is the same concept, but now the arm has the pin and the wheel, when turning, guides it back and forth. I'm sorry that I can't be more helpful, but take a look at the "how stuff works" site and you can surely find many examples of mechanisms that will do what you want.
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Cheers!
Chip Shults