Patent ID: 7520276

Claim:
Portable working machine comprising a tool unit ( 1 ) with a disc guard ( 5 ) and a circular, disc-shaped tool ( 3 ), which can be rotated about an axis of rotation ( 4 ), which is horizontal in the normal upraised position of the machine, and a machine unit ( 2 ), which includes at least a filter system ( 10 ), which is at least partly accommodated in a top part of the machine unit, an internal combustion engine ( 11 ) with an engine cylinder ( 13 ) with bore ( 12 ) having a centre line ( 30 ), a crankshaft ( 14 ) and a crankcase ( 15 ), as assembly ( 16 ) comprising members for supplying air and fuel to the engine, a fuel tank ( 17 ), a muffler ( 18 ) accommodated in a space located behind the disc guard ( 5 ) where the space has the substantial shape of a triangle in a cross section of said space perpendicular to said axis of rotation ( 4 ), with an entrance port ( 46 ) provided in the rear side ( 42 ) of the muffler and facing an exhaust port ( 47 ) of the cylinder ( 13 ), i.e. the muffler is directly mounted to the cylinder, handles ( 19 , 20 ), controls ( 21 , 22 ), and supports ( 23 , 24 ) on the underside of the machine unit for allowing upright positioning of the machine on a flat ground, and a tool carrier ( 25 ) unites the machine unit ( 2 ) and the tool unit ( 1 ) having a power transmission between the machine unit and the tool unit, comprising an endless driving belt ( 26 ), characterised in that the cylinder bore ( 12 ) is inclined forwards in a direction towards the tool unit, such that the centre line ( 30 ) of the cylinder bore forms a tilt angle (α) larger than zero, in said direction, to a perpendicular to any or both of the following lines: a) a base line ( 33 ), which is a line coinciding with a horizontal surface on which the machine is resting in an upright position, when said supports on the underside of the machine unit contact said surface, and b) a tangential tine ( 33 ′) extending from a peripheral point of the tool, on the lower part of the tool when the machine has an up right position, to the bottom side of a rear support ( 24 ) on the machine unit.