Patent ID: 7398834
Filing Date: 2008-07-15
Classification: B25D,Y10S

Abstract:
1. A hammer drill comprising: a motor; a tool holder capable of holding a cutting tool; a drive transmission selectably operable in at least one of a first mode of operation and a second mode of operation; a mode change mechanism connected to the drive transmission and operable for selecting one of the first mode of operation and the second mode of operation of the drive transmission; a switch which when in a closed position provides power to the motor; and a lock-on mechanism selectably operable to lock the switch in closed position; a first sensing apparatus producing a first signal indicating the mode of operation of the drive transmission; a second sensing apparatus producing a second signal indicating the condition of the lock on mechanism; and a controller which receives the first signal and the second signal and wherein, when the first signal indicates that the drive transmission is operating in the first mode, and the second signal indicates that the switch is locked in the closed position, then the controller interferes with the operation of the motor, and when the first signal indicates that the drive transmission is operating in the second mode, and the second signal indicates that the switch is locked in the closed position, then the controller allows normal operation of the motor.