Abstract: A reciprocating piston jack-hammer is provided with an easily detachable air distribution mechanism, a resilient casing for muffling the noise by the emitted air, and a shock absorbing housing. A cylindrical tube houses the reciprocating piston and has molded thereabout a housing with air channels between the housing and the tube. The handle of the jack-hammer has a cavity and a mechanism which controls the supply of compressed air to the distribution system. The distribution system employs two parts, one disposed in the other, with an oscillating pellet between the two parts, which oscillating pellet serves to distribute the incoming compressed air either to drive the piston or to direct the air to a piston relief channel, thereby returning the piston to the upper position. Upon return of the piston to its upper position, the air is exhausted from the cylinder below the piston out to a muffling exhaust chamber, out to the atmosphere.

Abstract: The invention is a unique air inlet control system for a distributor of a jack-hammer wherein the inlet control valve is mounted in the inlet passage so as to be pivotally movable by a sliding rod which is in intimate contact with the control trigger mounted in the handle as well as the valve body. The arrangement permits any force that is applied to the control trigger to be translocated to the valve body and thereby unseat the valve body. Further, when the force is removed from the control trigger, the compressed air acts on the sliding rod to allow the valve body to return to a sealed position.