# JIB pneumatic question.



## Mazz (Jun 24, 2007)

This year I would like to build a jack in the box where the front folds down and a clown pops out. My question is this: Would I need 2 cylinders? One for the clown on a scissor mech. and one to open and close the front of the box?
Thank you in advance,
Mazz


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## DarkOne (Oct 16, 2012)

You could probably run a rod from the bottom of the end of your scissor mech, to the backside of your hinged door. Just make sure it can rotate freely at the connection points. 

The weight of the door may want to pull on your scissor mech a little and you'd have to experiment with where to mount the attachments, somewhere above center. I'm not sure if this would require a larger cylinder or not, depends on what you have.

You could always buy two cylinders and valves, and if you need only one, you have an excuse to build another prop!


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## armysyco (Nov 4, 2014)

You could do it either way. Using two cylinders simplifies things and in theory it would be easier to adjust the two seperate motions to match what you want to happen. That being said, you could use one clyinder to trigger both. I'm sure there are several different ways of doing it, each with their own pros and cons. If I get a chance, i'll throw together a quick sketch to show the way that I am thinking of.


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## Mazz (Jun 24, 2007)

Thank you Darkone and Armysyco for your input. Good ideas, I'm still batting it around.


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## corey872 (Jan 10, 2010)

Toy JIBs seem to get by with one spring mechanism, so I don't know why a clever arrangement of a few rods couldn't do the same with yours. It just simplifies things quite a bit.

Ideally, I'd think you'd want some way to build up pressure in the cylinder, then have a solenoid 'pop' a release, setting the whole mechanism and door flying open. Then you'd have a slow retract of the cylinder where some type of link or lever would catch the door and pull it closed. Once everything is reset, the solenoid re-engages and pressure builds in the cylinder ready for the next 'pop'.


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