Patent ID: 6209678
Filing Date: 2001-04-03
Classification: B23B,B25F

Abstract:
In a pneumatic hand tool having a handle with an exhaust passage including a main section, a muffler improvement comprising:(a) an inner tube having a plurality of holes, the inner tube having distal and proximal end;(b) a cutoff wall located within the inner tube at a location between the inner tube proximal and distal ends, at least one hole being provided in the inner tube above the cutoff wall and at least one hole being provided in the inner tube below the cutoff wall;(c) an upper plate connected to the inner tube proximal end; the upper plate closing off the exhaust passage main section such that at least portions of the exhaust air is directed into the inner tube proximal end during use;(d) an end cap attachable to the handle for closing off the exhaust passage, the end cap having an exit opening adjacent to the inner tube distal end;wherein during hand tool use, exhaust air enters the inner tube proximal end, flows out the inner tube holes located above the cutoff wall, moves around the cutoff wall, moves back into the inner tube holes located below the cutoff wall, and flows out the exit opening of the end cap; whereby the tortuous path of the exhaust air slows it and assists in dampening exhaust noise.