I am trying to put together a small animation of some linked mechanical parts but I don't know where to start in terms of the animation tools that should be used.
To start off simple, I want to take a disc (or gear) that rotates and has a vertical shaft attached.  The shaft should raise and lower as the disc rotates.
I just need someone to point me in the right direction.

Thanks.

May I suggest the Cognito plugin, from DCG:

http://www.digitalcarversguild.com/plugin.php?ProductId=6

Cheers.

 If you want direct, mechanical interactions, Cognito will prevent you dying a slow death by keyframing.

Hi Tkane,

would something like this be enough? It's set without any plugin.
For a simple animation like this it's OK, but if you have something more complex
I think the setting will be much harder.

Thanks for the input, guys.

Faba,
That's exactly what I was trying to do.
So what's the secret?

That's a pretty good mechanical linkage you've got going there Faba. You could probably even use something similar for a very basic steam locomotive animation. Cognito does make life a lot easier for rigging up more complex linkages.

Another more simple example, I'll upload the file, so you can see it on your own.

Basically it's 2 chains that are connected at the white and the black objects.
I'll name the objects with their colors, because I think it makes it easier to understand:

Orange = rotating disk with spin modifier
White = parented to orange

Green-Blue-Black = IK-chain
Green = Slider, free in the z-axis, locked in x and y-axis
Blue = parented to Green, Ball joint with only 1 free axis (y)
Black = parented to blue, tracking white - full constraint (it's just there to follow white)

Here is the file:
www.evajoe.homepage.t-online.de/mechanics2.rar

Edit: typo

http://www.sparrowhawke3d.com/Sparrowhawke3DPlugins.html

Some free plugins here that can add to workflow abilities also.

excellent work, faba!

Thanks everyone.