Patent ID: 6834789
Filing Date: 2004-12-28
Classification: B25C

Abstract:
A compressed fluid operated fastener driving tool, which can be selectively triggered for driving fasteners into an underlying workpiece, said tool comprising a frame, a fastener feeder for feeding fasteners to a fastener discharge mechanism of said driving tool, said fastener driving mechanism capable of shifting between a rest and an operative condition, said fastener discharge mechanism comprising:a housing, comprising: a first chamber having a fluid inlet destined to be connected to a source of compressed fluid for keeping said first chamber pressurized, a second chamber, comprising first and second fluid inlet ports for admitting compressed fluid from said first chamber into said second chamber, said second fluid inlet port capable of being selectively opened and closed, said second chamber being selectively depressurizable, said second chamber being pressurized when said fastener discharge mechanism is in said rest condition; a third chamber, comprising a piston slidably mounted therein, said piston comprising a piston head and a plunger downwardly depending from said piston head, wherein said piston is biased from a first limit position towards a second limit position when said third chamber is in fluid communication with said first chamber, said piston being in said first limit position when said fastener discharge mechanism is in said rest condition; a valve controlling fluid communication between said first chamber and said third chamber, said valve being biased towards an open limit position when said second chamber is depressurized where fluid communication is established between said first and said third chamber, and said valve being biased towards a closed limit position when said second chamber is pressurized where fluid communication is interrupted between said first and said third chamber; wherein after said tool is triggered, said fastener discharge mechanism passes from said rest condition to said operative condition, said second chamber is depressurized to induce movement in said valve towards said open position,wherein when said valve is moved towards said open limit position, said second chamber second fluid inlet port is closed, and fluid communication is established between said first chamber and said third chamber, thus urging said piston towards said second limit position for allowing a fastener to be struck by said plunger and thus discharged from said tool;and wherein after said piston is moved towards said second limit position, fluid flowing into said second chamber through said first fluid inlet port pressurizes same and initiates movement of said valve towards said closed limit position, and wherein after initiation of movement of said valve towards said closed limit position, said second fluid inlet port is opened to accelerate pressurizing of said second chamber and thus accelerate movement of said valve towards said closed limit position.