Patent ID: 8276682

Claim:
In a continuous stroke pneumatic tool including: a body member having a longitudinal axis and a generally cylindrical bore therein, said generally cylindrical bore having generally axially opposed first and second ends; a piston element slidably received in said generally cylindrical bore for movement generally along said longitudinal axis in a power stroke towards said second end and in a return stroke toward said first end; a tappet element mounted generally at said second end and positioned to be impacted by said piston element at approximately the end of said power stroke; a pneumatic circuit associated with said body member, said pneumatic circuit including a supply conduit adapted to being connected to a continuous source of pressurized fluid, an on-off valve, said on-off valve being flow controllingly associated with said supply conduit, a control valve assembly mounted generally in said body member at approximately said first end, said control valve assembly having a power stroke side and a return stroke side, a return conduit extending generally between said return stroke side and said second end, said power stroke side being in fluid communication with said first end, and an exhaust port extending from approximately medial of said generally cylindrical bore to the outside of said body member; the improvement comprising: said control valve assembly comprising a ball valve assembly including a valve ball element, said valve ball element being substantially non-magnetizable and having a sealingly resilient surface, said valve ball element being loosely confined for at least about 0.005 inches movement between sealing engagement with a first concave generally conical surface on said power stroke side and sealing engagement with a second concave generally conical surface on said return stroke side, said first and second concave generally conical surfaces being generally opposed to one another and defining a valve chamber there between, a generally annular gas channel circumferentially surrounding and extending generally outwardly from said valve chamber, said generally annular gas channel being adapted to distribute gas from said supply conduit to said valve chamber around said valve ball element.