US Patent 7036605 Power tools

A detector is disclosed that detects impact sounds, e.g., a hammer striking an anvil or oil pulses from an oil unit. The detector may comprise a receiver that selectively converts sound within a narrow frequency range into electric signals. Preferably, the impact sounds fall within the narrow frequency range of the receiver. A processor may be utilized to control the motor in order to stop the rotation of the hammer when a pre-determined number of impact sounds has been detected by the detector. In addition, the operating conditions can be set by a number of methods, including dials, sound sensors, keypads and remote control devices. Further, means for performing maintenance condition status checks are taught.