| 摘要 |
PROBLEM TO BE SOLVED: To provide a combustion type power tool not lowered in driving energy by suppressing the rise of back pressure in a piston lower chamber in a cylinder even after a piston passes through exhaust holes. SOLUTION: The piston 25 in the cylinder 20 partitions the cylinder into a piston upper chamber in the cylinder on the combustion chamber 26 side, and the piston lower chamber on the anti-combustion-chamber side. The cylinder is formed with the exhaust holes 21, and combustion gas in the combustion chamber is exhausted to the outside air when the piston descends. A through hole 20a serving as a back pressure preventing passage is formed in the lower part of the cylinder, and the lower end of the cylinder is provided with blade guides 31, 32 for guiding the vertical motion of a driver blade 28 and formed with a guide clearance 29. When the piston descends, even after the piston passes through the exhaust holes, air in the piston lower chamber is exhausted to the outside air through the through hole 20a as well as the guide clearance to prevent the fall of descending speed of the piston. COPYRIGHT: (C)2005,JPO&NCIPI
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