Patent ID: 7207393

Claim:
A hand held power tool comprising: a. a housing; b. a motor disposed in the housing; c. a power source that energizes the motor; d. a cam shaft driven by the motor; e. a hammer driven by the cam shaft; and f. an anvil comprising: i. an anvil portion including a plurality of arms extending radially from a rear end of the anvil; ii. a tang formed at a forward end of the shaft and as a single piece with the anvil portion, the tang having a first section with a first bore and a second section without a bore disposed between the first section and the anvil portion along an axis to form an output portion to substantially eliminate any stress concentration at the output portion and, wherein the first and second sections of the tang each have a square cross section such the a width of the cross section of the first section is less than a width of the cross section of the second section; and iii. a torque transfer section disposed between the anvil portion and the second section along the axis; g. a sleeve bearing engaging the torque transfer section.