Patent ID: 7322114

Claim:
A saw chain tensioning mechanism for adjusting a tension of a saw chain of a chain saw, said chain saw including a chain guide plate for supporting a saw chain extending around said chain guide plate and a side case and a main body case for supporting the chain guide plate in a sandwiched manner therebetween, said saw chain tensioning mechanism comprising: a threaded rod member for positioning adjacent to a rear end of said chain guide plate and along a longitudinal direction of said chain guide plate; a movable member for engaging said chain guide plate and adapted to be moved along said threaded rod member by a rotation of said threaded rod member; a driven gear integral with said threaded rod member; a driving gear for rotatably driving said driven gear; a first knob for manually rotating said driving gear, whereby a longitudinal position of said chain guide plate is changed to adjust a tension of said saw chain; a second knob for manually tightening and loosening said side case and said main body case about said chain guide plate; and an intermediate gear interposed between said driving gear and said driven gear; wherein each of said driving gear and said intermediate gear is formed as a spur gear arranged to be aligned along said side case.