Power tool (11) may include a motor and oil pulse unit (22) that generates an elevated torque. Oil pulse unit (22) may be coupled to the motor and have output shaft (18). When load acting on output shaft (18) is less than a predetermined value, rotating torque generated by the motor is directly transmitted to output shaft (18). When the load acting on output shaft (22) exceeds the predetermined value, an elevated torque is generated by oil pulse unit (22) and applied to output shaft (18). Output shaft (18) may be connected to load shaft (12). A socket may be attached to the distal end of load shaft (12). Power tool (11) may further include detecting device (20) for detecting change in rotational angle of output shaft (18) and the direction of rotation thereof, and a control device. The detecting device (20) may output signals corresponding to a state of output shaft (18) to the control device. The control device may store the state of output shaft (18) at predetermined interval. Preferably, the control device may further determine a generating time, at which oil pulse unit (22) generates the elevated torque, based upon the state of output shaft (18).
Battery-powered tools may include battery 1 or battery pack BP and a drive source (e.g., motor M) for generating power using current supplied from the battery. A switch 3 may electrically connect the battery to the drive source. A voltage detector may detect the output battery voltage of the battery. Further, a processor 60, 210, a comparator 5 or another similar device preferably determines when a difference between (1) a first battery voltage detected at a first predetermined time period after the switch is turned OFF and (2) a second battery voltage detected at a second predetermined time after the first predetermined time period exceeds a predetermined value. This information may be utilized to determine whether to warn an operator of the battery powered tool that further operation using the battery 1 or battery pack BP should be discontinued.
The invention discloses a power tool for screwing or drilling having a motor for driving a drive shaft, a controller for controlling the power tool, a motor switch for switching the motor on and off, switch for reversing the power tool between clockwise and counter-clockwise rotation, and vice versa, and a timer that permits reversal of the power tool between clockwise/counter-clockwise rotation, and vice versa, within a predefined period of time between actuation of the switch for clockwise/counter-clockwise rotation and for operation of the motor switch to start the power tool.
An improved method is provided for controlling a power tool having a rotary shaft. The method includes: disposing an inertial mass in a housing of the power tool, such that the inertial mass is freely rotatable about an axis of rotation which is axially aligned with the rotary shaft; monitoring rotational motion of the power tool in relation to the inertial mass during operation of the power tool; and activating a protective operation based on the rotational motion of the power tool in relation to the inertial mass.
An improved method is provided for controlling a power tool having a rotary shaft. The method includes: disposing an inertial mass in a housing of the power tool, such that the inertial mass is freely rotatable about an axis of rotation which is axially aligned with the rotary shaft; monitoring rotational motion of the power tool in relation to the inertial mass during operation of the power tool; and activating a protective operation based on the rotational motion of the power tool in relation to the inertial mass.
