Help with pneumatic?

[siegomaestro]

Hey all,

I 'm working with something I've never done before , so I thought to ask if you can help me.
I'll open a window 100 degrees but I have to install the pneumatic air cylinder and I do not know how to proceed .
Where's the best place to assembly the air cylinder ?
How do you calculate ?
All tips and suggestions are welcome.

Br Siegomaestro

 

[monkeydog]

Do you mean like this?

http://www.amazon.com/s/?ie=UTF8&ke...vptwo=&hvqmt=b&hvdev=c&ref=pd_sl_3mewftn4c1_b

 

[EdStainless]

Gas spring (strut) or air cylinder (with compressed air supply, regulator, and control valves)?
Simple mechanics problem, knowing the compressed and extended sizes you can figure out where it will fit, then knowing the weight of the window you can check the loads.

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P.E. Metallurgy, Plymouth Tube

 

[KENAT]

Potentially not so simple mechanics problem if you mean gas struts & care about how smooth/fast/easily it opens and closes and how much user force is required to push it closed etc. because the C of G of the window and the point the gas struts apply their force moves significantly relative to the pivot (hinge) as it opens/closes.

The more reputable strut manufacturers should give you guidelines on this & even help with the design, I believe our vendor for something that may be similar use ACE gas springs

http://ace-ace.com/wEnglisch/pages/Produkte/index.php?IdTreeGroup=266#hk_1

Gas strut performance will normally vary with temperature - both environment temp but also the heat they generate from repeated operation. Can make setting the force tricky on adjustable struts.

You may be able to come up with an 'over center' implementation where at top of flap opening the struts are helping to open it/hold it open but when it gets nearly closed the gas struts actually help to close it. This can help tune the required closing force as well as helping keep it closed.

Also consider safety - e.g. do you need some kind of locking device to keep it open in the event of a gas strut failure. Struts with this built in are available but the ones I've seen are a little kludgey and I wasn't too impressed.

Also consider ergonomics of what the maximum closing and opening forces should be to avoid strain on the operator.

Sorry can't say much more due to IP concerns but will say that we've been working with a vendor who makes a vaguely similar enclosure for months now trying to optimize the force.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[siegomaestro]

I thank you for the time you have taken and answered . I want air cylinder with strip valves and full -package , because of this shall be automatic and programmed with out people sometimes . I have to get the window closed completely by using these air cylinder and frequent so no hot air comes out . Regarding air cylinder you must have the strength to lift and turn , I wonder if it bothered pulling up perfectly vertical ?

 

[Jboggs]

Random thoughts/questions:
"so no hot air comes out" Hot air? How hot? That could effect your cylinder.
How much of a seal are you talking about? Air-tight, or just relatively leak free? Is the pressure inside above ambient?

What is a "strip valve"? Do you mean directional valve?

To size the cylinder you have to create a free-body diagram with all the connection points in the worst-case position to calculate how the weight of the door translates into force on the cylinder.

You may not know how to do this, but you have to start somewhere. Make a diagram of what you think the cylinder mounting, connections, and stroke might look like, and go from there.

Also, I would plan on two cylinders to prevent warping the door.

 

[mcgyvr]

Also, I would plan on two cylinders to prevent warping the door.

Good luck keeping them in sync..

 

[Jboggs]

I understand, and agree. But the cost to synchronize appears to be beyond the scope of this project to me. Keeping things simple for the OP.

 

[EdStainless]

Your freebody diagram needs a few items, force to open, force to hold open, how tightly you want to hold it closed, and range of motion. You will need to look at different cylinder positions and mounting methods to achieve the correct motions.

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P.E. Metallurgy, Plymouth Tube

 

[LittleInch]

Basically the connection on the window needs to be level or higher than the other end when the window is closed, but has sufficient extension so that the window will open your 110 degrees. Peak load will probably be at the end as the window reaches maximum cantilever from the hinge, but a couple of quick sketches at 10 degree slices will provide you with that information.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.