Abstract
For driving of multi parallel cylinders, so called barrel type as Daidoji, Aishin and Clucus Engines^<(1)(2)(3)> etc, there were many ways. But, we have found that, if Z crank is used, the driving ball's center moves up and down along the surface of small circular pillar. So, new piston driving mechanism using this fact is now under developments for less friction and simplicity.
