Patent ID: 7490582
Filing Date: 2009-02-17
Classification: B25C

Abstract:
1. The combustion-type power tool comprising: a housing; a cylinder disposed in the housing and having a peripheral wall, wherein at least one exhaust hole is formed in the peripheral wall; a piston slidably disposed in the cylinder; a combustion-chamber frame disposed in the housing and movable in an axial direction; and a first group of fins disposed on an upper portion of the peripheral wall, said first group of fins including at least one straight fin extending in the axial direction and at least one bent fin having a first portion extending in parallel with the at least one straight fin of the first group of fins and a second portion extending in a direction slanted in relation to the axial direction and oriented toward the at least one exhaust hole; wherein the first group of fins includes a plurality of bent fins having first portions with different lengths from each other.