Pneumatic Piston Weight

[Madison]

We're looking at potentially using several 2" bore cylinders, some with 12" or 24" stroke, but I have many concerns regarding the unnegotiable weight these components add to the robot. I don't know, however, the actual weight of such components and I only have a nebulous idea from years past that they're really heavy.

I know that there was available somewhere information about the weight of pistons in the format (XX lbs. + YY lbs./in. stroke), but I can't find it anywhere. Can someone kindly point me to that information? Thanks.

[Max Lobovsky]

I don't know the weight, but there is another issue you should be aware of because it sounds like a bad idea to me regardless of the weight. If I remember correctly, moving a single 2x24 cylinder once drains both your storage tanks almost entirely. If you plan to be using these with any frequency, you will run out of air.

[Madison]

Originally Posted by Max Lobovsky

I don't know the weight, but there is another issue you should be aware of because it sounds like a bad idea to me regardless of the weight. If I remember correctly, moving a single 2x24 cylinder once drains both your storage tanks almost entirely. If you plan to be using these with any frequency, you will run out of air.

I'm quite aware of the other issues inherent in using these large pistons. I am interested in their weight so that I might see what I'm getting for money, so to speak, with respect to force exerted and component weight.

[David Hoff]

Last year Cyber Blue used 2'' bore pneumatics that had 24'' and 6'' strokes. Our weight database says that the 24'' was 5.22 pounds and that the 6'' was 2.52 pounds.

[Madison]

Originally Posted by David Hoff

Last year Cyber Blue used 2'' bore pneumatics that had 24'' and 6'' strokes. Our weight database says that the 24'' was 5.22 pounds and that the 6'' was 2.52 pounds.

Thanks, David. I saw this on your spreadsheet just a bit earlier and am now searching for similar information for 1.5" and 3/4" bore pistons.

For 2" bore pistons, this means that there's a base weight of 1.62 lbs. with an additional .15 lbs. for each inch of stroke.

[Gary Bonner]

From the 2003 pneumatics manual:

Approximate weight calculations for custom cylinders, not including the rod clevis or pivot brackets:
3/4" Bore 0.21 lbs. + 0.03 lbs. per inch of stroke
1/2" Bore 0.73 lbs. + 0.08 lbs. per inch of stroke
2" Bore 1.62 lbs. + 0.15 lbs. per inch of stroke

[Matt Adams]

Originally Posted by M. Krass

Can someone kindly point me to that information? Thanks.

http://www.bimba.com/pdf/bmol.pdf

Something to consider as well....

In our design we were considering using a number of large stroke pneumatics to pull up stages in a lift, and realized that we could reduce those stroke lengths significantly by using pulley systems, effectively using mechanical advantage.

The picture attached basically shows that by pulling the lower pulley down, it will require twice as much force, but make the other end of the string around the upper left pulley move twice as far (and twice as fast). Most pneumatics have much more force available then what you'll need, so this might be an effective way to reduce the required stroke lengths, if this is indeed your application.

If it's not, then maybe someone else will enjoy another addition to the collection of world famous art, aptly titled, "Art by Matt"

Matt