There, I Fixed It!

I have a chair in my office that has one of those pneumatic height adjusters. I've had the chair for I don't know how long and it won't hold it's position any more. So I fixed it. I was thinking of submitting it to the website (There, I Fixed It.), but I thought it's really not Rube Goldberg enough to be worthy, but my blog? Heck yeah! That's a u-bolt clamp for an antennae I found in my junk box clamped onto the seat post cylinder rod. The chair is on it's side.

I always thought these pneumatic cylinders were just begging for a come down. I mean they depend on the seals and valves ABSOLUTELY NOT leaking. This requires a perfect finish on the piston rods, the valve seats, every portion of the device were air could leak through. And then you need plastic/rubber seals that never wear out. It just seemed to be too much much to ask for. But this is only the second failure I've encountered. I replaced the gas lift struts on my wife's SUV last year.

Before we had pneumatic cylinders in office chair posts, we had the big metal screw with a collar that you twisted to adjust the height. The collar contained a bearing that allowed the chair to swivel, and some kind high drag internal threads that insured that it would not rotate on the big screw and change the seat height. They were kind of a pain to adjust. You had to tip the chair on it's side, or get down on the floor in order to reach the nut. On pneumatic chairs, you simply pull the little lever on the side of the chair that you can easily reach from where you are sitting.

So it looks like automated machining (CNC) has reached the point where it is cheaper to make a simple high precision piece than a simpler, cruder device.

Update January 2017 replaced missing picture. Also, the clamp did not really fix the chair, the surface of the chrome shaft was too hard for the clamp to get a purchase, so it slide down a bit, not as much as before, but it didn't hold right at the top either. The clamp is still there and I am still using the chair. Not bad for a $40 chair from Office Depot.