[SML] Air bladder system for pushing down casters....

[Greg Bierly]

Rose Brand sells just such an item but very expensive.  https://www.rosebrand.com/product3896/Pneumatic-Lift-Triple-Swivel-Caster.aspx?tid=2&info=air%2bcaster
Our first round of air lift casters were octagonal boxes made out of 2x6 framing with some surplus 1.25” plywood sandwiching small wagon type inner tubes.  They worked but were large and clunky.  We waxed the moving parts to keep them from binding and used triple swivel casters. 
I found any time you are lifting like this, triple swivels work the best otherwise you tend to side load a standard single swivel.  
Our next set used FABCO pancake cylinders to push the triple swivels down.  Eventually we used spring return cylinders eliminating duplicate air lines to retract the casters.  

I had stumbled onto a pneumatic locking caster being sold by Spoon Group a number of years ago at USITT.  I was able to reverse engineer them and make my own for about 1/2 the price.  They are based on the 4” Cartmaster Caster sold by Rose Brand.
https://www.rosebrand.com/product2877/4-Cartmaster-Caster.aspx?tid=2&info=caster
We CNC’ed the fitting to hold the caster and include a low profile pancake cylinder.  They work very well on smaller scenery.  

I have never seen the Spoon Group caster for sale again (thus the reverse engineering) I did find the patent for them and have considered reaching out and seeing if they are for sale anywhere.  I feel every theater should have a dozen in their stock as useful as they are.  



Greg Bierly


> On Aug 5, 2024, at 5:01 PM, Jon Ares via Stagecraft <stagecraft at theatrical.net> wrote:
> Has anyone tried building a system using something like these,
> commonly available today?
> https://www.amazon.com/IMPROVED-Commercial-Professional-Alignment-Inflatable/dp/B09F34QGB6/



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