I need to animate a crank and shaft. As the wheel turns, the crankpin on the wheel moves a connecting-rod that raises and lowers a hammer-bar. The hammer-bar, pivoted on the other end, rotates on a semi-circular path as the connecting rod rises and falls.
The question is, how do you model this? The mechanism will turn quite slowly (about 4 RPM) so the animation needs to be fluid. I’ve been thinking that I should mathematically describe this, maybe use a one-time Python script. I thought about something with armatures but that doesn’t seem to apply. Recommendations anyone?
Let’s see… Well, screen capturing ain’t happening so let me describe it again.
You know those oil-well pumps that bob up and down as a wheel turns? Bingo! I’m trying to model something like that.
Now, what I want to do is to get the correct positions for the arm that bobs up and down, and for the crank-pin that pushes it up and down, as the wheel turns smoothly in a full rotation.
All I need to obtain is one smooth cycle of the animation, which then repeats itself.
And here I thought it would be hard. (Nope, just undocumented.) %|
For my purposes, it appears that the “constraints” strategy (described in the “meccano” page above) ought to be adequate for the moves I need to do. But the “armature” strategy (described in the PDF file) could be very useful for things like flying overhead cranes and hooks… things that consist of cables and hoses.
You really can do anything with Blender! 
8)