The page is in Japanese, but the first image you see is a pic of a S-Type keg opening tool. If someone had good fabrication skills you could probably knock one of these out pretty easy.
There are other pics on the site that show more angles.
that was easy i just put a screwdriver in there under the ball ,till the assembly started moving around ..hit the tabs on top afew times with a big screwdriver till it started unthreading and it came right out
Scouring the internets....found an incredibly easy way to release the locking mechanism. And no damage at all. Put a nickel on top of the ball then attach your sanke coupler as you normally would. This releases the locking mechanism. Now just pull the whole assembly out. Just did it, nice and easy.
I just got my hands on 5 of these suckers. I built the jig and got one spear out but it looks like the spring inside the valve is not letting the safety in all the way on a couple of them. Its like when it gets depressed it gets in the way of the little safety from being pushed all the way back and the spear won't come out. How do they do this at the brewery? There's got to be some kind of pre-fab tool right? I'm converting 3 of these to brew in but would like to keep 2 in good shape to carbonate and serve in. As soon as I get these suckers out I'm pulling that safety off!
The picture I posted above is a 'pre-fab tool' for getting the plunger out of sankey s type kegs. In most breweries they almost never actually take out the plungers. They just steam pressure clean them through the coupler and refill them.
I have one of the above keg openers now and it is a joy to use. If I can remember I will take some better pics so people can make them at home. Once you have one made all you need to do is turn the thumb-screw to release the safety and then crank out the whole apparatus. Depressurizing and opening a keg takes me about 30 seconds now.
I'm cooking with gas now. I think I just needed a longer screwdriver to get a little moe pressure on the safety. Now that I have the spears out I think I'm going to remove the safeties for easier handling. Thanks for the response.