Patent ID: 6557648
Filing Date: 2003-05-06
Classification: B25D

Abstract:
A hammer drill comprising:a motor rotating a drive shaft; an external frame member accommodating said motor therein; a first gear having a claw portion and engaged with said drive shaft for transmitting the rotation of said drive shaft; a second gear having a claw portion and engaged with said drive shaft for transmitting the rotation of said drive shaft, said first and second gears being positioned in parallel with each other; a first switching member having a claw portion engageable with said claw portion of said first gear for transmitting the rotation of said drive shaft when said claw portion of first switching member is engaged with said claw portion of said first gear; a crank shaft driven in response to the rotation of said first switching member; a striking force transmitting mechanism responsive to the rotation of said crank shaft for transmitting a reciprocative striking force to a tool bit; a second switching member having a claw portion engageable with said claw portion of said second gear for transmitting the rotation of said drive shaft when said claw portion of second switching member is engaged with said claw portion of said second gear; an intermediate shaft driven in response to the rotation of said second switching member; a rotational force transmitting mechanism responsive to the rotation of said intermediate shaft for transmitting a rotational force to said tool bit; and a switching lever for selectively engaging or disengaging said claw portion of first switching member with or from said claw portion of said first gear and also selectively engaging or disengaging said claw portion of second switching member with or from said claw portion of said second gear.