For sale is a ARO Pneumatic Chain Hoist. This is a 2 ton (4,000 lbs) double chain version. Parts are still available. The control arm, whose function is to prevent overtravel by the hook of the free end of the chain, is broken. I called Ingersoll Rand and was quoted $78 for a replacement. Its only function is to prevent overtravel, so if you are careful you can just live without it.
I did apply compressed air to this hoist and it happily goes up and down.