A fastener driving tool powered by internal combustion of an air/fuel mixture. A tool body has located therein upper and lower coaxial cylinders containing upper and lower pistons, respectively, attached to a common driver and forming a piston/driver assembly shiftable between a normal retracted position...http://www.google.es/patents/US4717060?utm_source=gb-gplus-sharePatente US4717060 - Self-contained internal combustion fastener driving tool
