Patent ID: 8267189

Claim:
A hand-held power tool, comprising: a pneumatic percussion mechanism ( 20 ) defining a central pneumatic mechanism axis (S); and a motor ( 12 ) for driving the percussion mechanism ( 20 ); wherein the percussion mechanism ( 20 ) includes: a guide tube ( 21 ), an impact member ( 23 ) displaceable in the guide tube ( 21 ), a reciprocating driving member ( 22 ) for driving the impact member ( 23 ), a gas spring ( 25 ) located between the driving member ( 22 ) and the impact member ( 23 ) for transmitting a driving motion of the driving member ( 22 ) to the impact member ( 23 ), a motor-driven eccentric wheel ( 17 ) rotatable about a stationary, with respect to the power tool, axis (D), the axis (D) being spaced from the percussion mechanism axis (S) in a direction perpendicular to the percussion mechanism axis (S) by a distance (X) wherein the distance (X) between the rotational axis (D) of the eccentric wheel ( 17 ) and the percussion mechanism axis (S) lies in a range from 10% to 80% of a radius (RE) of the eccentric wheel ( 17 ), and a connection rod ( 29 ) eccentrically supported on the eccentric wheel ( 17 ) and connected to the driving member ( 22 ) for converting a rotational movement of the eccentric wheel ( 17 ) into a reciprocating movement of the driving member ( 22 ).