# How to achieve rotating Action?



## kaiarack (Oct 23, 2012)

Hello, 
I cant seem to find any tutorials or ideas on how to acheive a twisting action on a pneumatic pop up (see video link below). Does anyone have any ideas or examples they can point me to?

Thanks in advance


----------



## jdblue1976 (Nov 18, 2010)

Using my engineer's brain, this looks to be a combination of a spring and cam. Watch it closely, it is still rotating even though it is fully extended up. That looks like spring action that causes it to face out. Then as it goes down it smoothly returns which is a cam action.


----------



## jdblue1976 (Nov 18, 2010)

And the nice touch on this prop is the springy arms. They really make it dynamic. The shoulders look to be stiff springs.


----------



## Rage (Oct 23, 2012)

I have to agree with jdblue I think it's a cam as well, if you take a flat bar and give it a half twist with a flat plate on the bottom then place a air cylinder connected another flat plate with a fork actuator so one plate slide on the other then you'd have the same effect. I was thinking about doing the same thing with a crank ghost for the head only so that as it goes up it looks to the right and then the left, same process on the downward trip. Just to add more movement to the effect.


----------



## craigsrobotics (Oct 12, 2009)

See this http://www.wildrice.com/Halloween/Construction/LiftnTurn/


----------



## R. Lamb (Oct 11, 2011)

My first thought was Jack screw. But I'm no engineer.


----------

