Impact power tools

A power tool adapted to tighten a fastener, comprising;

• a motor,
• a hammer rotatably driven by the motor,
• an anvil operably disposed to continuously contact and be driven by the hammer during a normal tightening operation and to be struck by the hammer when an elevated torque is generated,
• a sensor detecting impact sounds generated by the hammer striking the anvil in order to generate an elevated torque and
• a microprocessor in communication with the sensor and the motor, the sensor communicating detected impact signals to the microprocessor each time that the hammer strikes the anvil, wherein the microprocessor contains an operating program that determines, based upon the detected impact signals, whether each detected impact sound was generated either (1) before the fastener has reached a seated position against a workpiece or (2) after the fastener has reached the seated position against the workpiece, and wherein the microprocessor is further programmed to automatically stop the motor based only upon detected impact signals that are determined to have occurred after the fastener has reached the seated position against the workpiece.

A power tool comprising:

• a drive source,
• a control device for controlling the drive source according to either a selected or a pre-determined operating mode,
• means for setting the selected operating mode, the setting means being in communication with the control device,
• a switch for switching the selected operating mode set by the setting means to the predetermined operating mode, wherein the control device drives the drive source in the predetermined operating mode when the switch is operated according to a predetermined condition, and the control device drives the drive source in the selected operating mode set by the setting means when the switch is not operated according to the predetermined condition.

A power tool comprising:

• a motor,
• means for generating an elevated torque coupled to the motor,
• a trigger switch for energizing the motor,
• a microprocessor controlling the motor according to either a manual operating mode or a normal auto-stop operating mode, which manual and normal auto-stop operating modes are stored in tho microprocessor, the microprocessor further comprising a timer for determining a time interval between the trigger switch being switched to an ON position after having been switched to the OFF position, wherein the microprocessor is programmed to control the motor (1) according to the normal auto-stop operating mode when the detected time interval is greater than a set time interval stored in the microprocessor and (2) according to the manual operating mode when the detected time interval is less than or equal to the set time interval stored in the microprocessor and
• a setting device in communication with the microprocessor, the setting device is capable of causing the microprocessor to switch from the normal auto-stop operating mode to the manual operating mode.