POWER CUTTER

摘要

A power cutter powered by a single cylinder internal combustion engine, the power cutter comprising: a tool unit having at least one tool, which can be rotated about an axis of rotation (108); a drive unit (104) comprising an engine, the engine comprising an engine cylinder having a cylinder bore centreline (138), a piston (140), a crankshaft with a crankshaft axis of rotation (118) and a flywheel (186), the crankshaft running in a counter clockwise direction (?) as seen towards the flywheel (186); a cutter arm (148) attached to the drive unit (104) in its inner end (148A) and its outer end (148B) carrying the tool unit, a centerline (146) of the cutter arm essentially follows a connection line (146) between the axis of rotation (108) of the tool and the axis of rotation (118) of the crankshaft; Especially the crank web/s (190) are arranged to counterbalance approximately a half piston weight and the flywheel is arranged so that it gives a radially outwards acting unbalance force FB during engine rotation (?), and FB is provided at a flywheel angle (?) in a clockwise direction in relation to the cylinder bore centerline (138) when the piston (140) is in a top dead center position, and the flywheel angle ? is larger than 20° but smaller than 110° in order to at least minimize cutter arm (148) bending stresses.