Self-contained internal combustion fastener driving tool
First Claim
1. A fastener driving tool comprising a tool body, upper and lower coaxial cylinders located within said tool body, each of said cylinders having upper and lower ends, upper and lower pistons located in said upper and lower cylinders respectively and fixedly mounted on a common driver forming a piston/driver assembly, said piston-driver assembly being shiftable between a normal retracted position and an extended fastener driving position, the upper end of said lower cylinder and said lower piston defining a combustion chamber, ignition means within said combustion chamber, a chamber in said tool body containing pressurized combustion air, at least one chamber in said body containing return air under pressure, a source of gaseous fuel under pressure within said body, and control means to introduce into said combustion chamber a measured air/fuel mixture from said combustion air chamber and said gaseous fuel source, to actuate said ignition means to combust said air/fuel mixture and thereby shift said piston-driver assembly from said normal retracted position to said extended fastener driving position, to introduce air from said at least one return air chamber to said upper cylinder beneath said upper piston to shift said piston/driver assembly from said extended fastener driving position to said normal retracted position and to exhaust spent products of combustion from said combustion chamber and lower cylinder, and means to replenish air under pressure in said combustion air chamber and said at least one return air chamber during shifting of said piston/driver assembly.
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Accused Products
Abstract
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 and an extended fastener driving position. A combustion chamber at the upper end of the lower cylinder and having an ignition device therein. The tool body contains a combustion air chamber and at least one return air chamber, together with a source of gaseous fuel. A trigger actuated control valve is configured to introduce a measured air/fuel mixture from the combustion air chamber and the source of gaseous fuel into the combustion chamber, to actuate the ignition means to combust the air/fuel mixture and shift the piston/driver assembly to its extended position, to introduce air from the at least one return air chamber to the upper cylinder beneath the upper piston to return the piston/driver assembly to its normal position, to exhaust the combustion chamber and to replenish air in the combustion air chamber and the at least one return air chamber.
84 Citations
34 Claims
- 1. A fastener driving tool comprising a tool body, upper and lower coaxial cylinders located within said tool body, each of said cylinders having upper and lower ends, upper and lower pistons located in said upper and lower cylinders respectively and fixedly mounted on a common driver forming a piston/driver assembly, said piston-driver assembly being shiftable between a normal retracted position and an extended fastener driving position, the upper end of said lower cylinder and said lower piston defining a combustion chamber, ignition means within said combustion chamber, a chamber in said tool body containing pressurized combustion air, at least one chamber in said body containing return air under pressure, a source of gaseous fuel under pressure within said body, and control means to introduce into said combustion chamber a measured air/fuel mixture from said combustion air chamber and said gaseous fuel source, to actuate said ignition means to combust said air/fuel mixture and thereby shift said piston-driver assembly from said normal retracted position to said extended fastener driving position, to introduce air from said at least one return air chamber to said upper cylinder beneath said upper piston to shift said piston/driver assembly from said extended fastener driving position to said normal retracted position and to exhaust spent products of combustion from said combustion chamber and lower cylinder, and means to replenish air under pressure in said combustion air chamber and said at least one return air chamber during shifting of said piston/driver assembly.
Specification