Category: Dropship

Had some good weather this weekend so I was able to get the Numatics E22 hooked up to the big Numatics air spring. I thought we had a problem the first time I started it up:

Turns out it needs a command signal (verifying with Numatics) anytime the unit is on (probably will make that computer-controlled with a SSR).

Once I applied the command signal it was very responsive with no weight. Didn’t get a chance to load it up yet though.

One other item that I contacted Numatics about was this 1/8″ (?) FNPT port on the back of the unit (side opposite of the readout panel). It leaks air proportionate to the pressure setting. I think it might be for an analog gauge but I wanted to make sure before I plug it.

It is not installed yet but I took a picture of the size comparison before it started raining again this morning.

You can see the old pair of mounting bolts by the CG symbol in the top right.  The new actuator has 4 mounting points – substantially bigger than the old one but is it enough?

Paraphrased from Continental’s website:

The lateral stiffness of air bellows differs greatly from type to type. For the individual air bellows types, the following lateral stiffness values – relative to the axial stiffness – can be expected. The specified percentages are for the recommended operating height for vibration isolation.

 

Single convolution 30 to 60%

Double convolution 5 to 30%

Belted 30 to 50%

Triple convolution 0% (not recommended)

Rolling lobe 0% (without restraining cylinder)

Sleeve type 0% (without restraining cylinder)

Happy Independence Day!

The E22 I ordered didn’t arrive as expected while I was on vacation… I guess this is what I get by dealing with a local distributor instead of online order, tracking, delivered.  They are looking into it.

I had some time this morning and spent almost 2 hours playing with the motion platform and test bench program.  At half the weight (1200 pounds) I had it working pretty well and had made several tweaks to the program to account for non-linearity, etc.  So I added the additional 1000 pounds and found it to be too squirrely at low PSI settings… I really was running out of time so I tried to retract the whole platform into it’s storage position and had a lot of trouble keeping it lined up – it actually wedged the back left bellow’s top convolute above the metal frame (probably very bad for the rubber) before I realized and repositioned it.

I am wondering now since it worked well at half the weight if getting larger diameter bellows would help… maybe I will get one or two and see.

Finally, the Air Lift Dominators that I purchased have a minimum height specification of 2.8″ so I built the frame to hold the weight off of them at 3.0″.  However, it still seems as if the weight is resting on the fully retracted bellows (I thought that was a no-no).  So I am contacting the company about that.

First we tested the convoluted bellows with an existing 500X unit (20 SCFM). The inflation speed was acceptable for the money it would save, but the deflation speed is too slow due to the small body ports.

[youtube http://www.youtube.com/watch?v=btkGUmEkhyI]

Second we tested the bellows with the M2d proportional valve (60 SCFM). It isn’t a closed-loop system so we can’t control the pressure and the M2d is half wasted because it is meant for double-acting actuators.

[youtube http://www.youtube.com/watch?v=1kjyOqR-SQE]

So in the end I think the E22 (100 SCFM) will be more than enough and it has full 1/2 FNPT exhaust and is about $200 cheaper than the M2d. I will install the 500X units temporarily for testing and so I can lift the platform up and work underneath without jacks.

[youtube http://www.youtube.com/watch?v=Fj5QZCK8U9Y]

Made one of these for my brother-in-law’s birthday and one for me.  These are authentic CWU-27/P Nomex (flame retardant) Flight Suit Flyers Coveralls Sage Green Size 44L.  He loved it!

With a little help from this guy’s blog I have been able to combine specular highlighting with displacement mapping!