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From: Viorel on 10 May 2010 14:58
Hello,

I intend to simulate in Simmechanics this mechanism shown here.
http://www.youtube.com/watch?v=C26DWO0GqPY

On the forum and in the help files I’ve got some info, but not enough to make something usable.

Now, let me describe a little the mechanism that makes me sleepless.
1 - the base (black color)
2 - the leg (red color)
3 - the ejector (blue color)
4 - a compression helical spring that I haven’t shown into the animation. The spring it is put inside the ejector, you can see the carved area into the ejector.

Basically I need to find out what is the necessary force that the spring must generate, to make the leg roll over. I forget about the friction here in the joints or with the air.

How it works:
a. The simulation starts with the spring being compressed (height=35mm) and with the ejector (1) resting on the base (2).
b. The spring is released rapidly, the ejector still stays in contact with the base (1) but the leg (2) it starting to rotate around its joint
c. Now the energy is big enough and we have a take-off : ) The ejector (3) have a linear travel of 50mm. The spring (4) has a free height of 85mm (35+55)
d. Now the leg (2) is rotating, given the applied impulse until it falls on the right side of the base

Problems:
I. How to specify that the ejector (3) only rests on the base (1). In Solidworks there’s a 3D contact option, there is a similar one in Simmechanics?
II. How to specify that the ejector moves only 50mm linear travel and then moves solidary with the leg? Also can I input the the spring has energy only for 50mm?
III. Here there’s not some easy joint to make the moves easy to simulate. That 3D contacts makes me mad :(

If you have any ideas/hint of how to implement this design I’ll be more the happy if you’ll share them.

Thank you for reading this long post :)
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