| 摘要 |
A combustion powered fastener driving tool 10 comprises a single cylinder combustion motor 14. The cylinder comprises an exhaust valve 70 and a piston 24 with an attached driver blade 22. The cylinder defines a path for the piston 24 and the attached driver blade 22, with the piston 24 and the attached driver blade 22 reciprocating between a pre-firing position before the combustion of fuel in the cylinder, and a bottom out position after combustion. The exhaust valve 70 is a check type valve with an exhaust port, and is configured to allow the exhaust of combustion gases from the cylinder but prevent the influx of air into the cylinder thus producing a thermal vacuum after combustion. The exhaust port is dimensioned as a function of the volume of the combustion chamber which is defined in part by the upper edge of the piston, such that sufficient gas is released from the cylinder to reduce the atmospheric pressure in the cylinder to approximately 1 atmosphere in the time it takes for the piston to travel past and return to the exhaust valve.
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