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A fastener driving tool powered by internal combustion of an air/fuel mixture. The tool body contains connected upper and lower coaxial cylinders. The upper cylinder is provided with a piston assembly and is connected by a one-way valve to a combustion air chamber. The lower cylinder contains a pist

A fastener driving tool powered by internal combustion of an air/fuel mixture. The tool body contains connected upper and lower coaxial cylinders. The upper cylinder is provided with a piston assembly and is connected by a one-way valve to a combustion air chamber. The lower cylinder contains a piston/driver assembly and is surrounded by and connected to a return air chamber. The upper cylinder piston assembly and the lower cylinder piston/driver assembly, when in their normal unactuated positions, define therebetween a combustion chamber provided with an ignition device. A positive trigger-actuated cam system, upon actuation of the trigger, is configured to open a fuel valve to introduce a measured amount of gaseous fuel from a source thereof into the combustion chamber; to thereafter open an air valve to introduce a measured quantity of air from the combustion air chamber into the combustion chamber; to next actuate the ignition device to combust the aire fuel mixture causing the lower cylinder piston/driver assembly to drive a fastener and to fill the return air chamber with air under pressure in the upper cylinder piston assembly to replenish air under pressure in the combustion air chamber; and finally to actuate a control valve operating an exhaust valve eliminating products of combustion enabling the upper cylinder piston assembly to return to its normal position and air from the return air chamber to return the lower cylinder piston/driver assembly to its normal position.

대표청구항 ▼

An internal combustion fastener driving tool comprising a housing, upper and lower coaxial cylinders located within said housing, said upper cylinder having a closed upper end and an open lower end, said lower cylinder having a closed lower end and an open upper end, said open cylinder ends being ad

An internal combustion fastener driving tool comprising a housing, upper and lower coaxial cylinders located within said housing, said upper cylinder having a closed upper end and an open lower end, said lower cylinder having a closed lower end and an open upper end, said open cylinder ends being adjacent to and in communication with each other, a piston assembly in said upper cylinder, said piston assembly being shiftable between a normal retracted position adjacent said open lower end of said upper cylinder and an actuated position adjacent said closed upper end of said upper cylinder, means biasing said piston assembly to said normal retracted position, a piston/driver assembly located in said lower cylinder and comprising a piston affixed to an elongated driver, said driver extending through a perforation in said closed lower end of said lower cylinder, said piston/driver assembly being shiftable within said lower cylinder between a normal retracted position with said piston of said piston/driver assembly at said open upper end of said lower cylinder and an extended fastener driving position, said piston assembly and said piston/driver assembly when in their normal positions defining therebetween a combustion chamber, ignition means in said combustion chamber, a chamber in said housing containing pressurized combustion air, the upper end of said upper cylinder being connected to said combustion air chamber through a one-way valve, a return air chamber in said housing, the lower end of said lower cylinder being connected to said return air chamber, a source of gaseous fuel under pressure within said housing, and control means for sequentially introducing into said combustion chamber a measured amount of gaseous fuel from said source, for introducing into said combustion chamber a measured amount of air from said combustion air chamber creating an air/fuel mixture, for actuating said ignition means to combust said air/fuel mixture in said combustion chamber thereby shifting said piston assembly of said upper cylinder from its normal retracted position to its actuated position replenishing air under pressure in said combustion air chamber and thereby shifting said piston/driver assembly from its normal retracted position to its fastener driving position driving a fastener and introducing air under pressure from said lower cylinder to said return air chamber and for exhausting spent products of combustion from said combustion chamber and lower cylinder permitting said piston assembly to return to its normal retracted position under the influence of said biasing means and said piston/driver assembly to return to its normal retracted position under the influence of pressurized air from said return air chamber.