PORTABLE POWER TOOLS

摘要

A portable power tool comprising a housing defining a combustion chamber and a cylindrical chamber having a reciprocating piston therein. The combustion chamber has an opening defined by a valve seat closable by a poppet valve and serving as an inlet at one side for unburnt gases or vaporized fuel admitted under pressure and an output at an opposite side for spent gases. An ignition assembly is provided for igniting unburnt fuel in the combustion chamber which is synchronized with the closure of the poppet valve. The combustion chamber and the poppet valve are shaped and arranged such that unburnt fuel admitted through one side of the valve seat opening will sweep the spent fuel of a preceding ignition cycle from the combustion chamber out through the other side of the valve seat opening.