Patent ID: 8347978

Claim:
A method comprising: providing a driving tool having a driver and a motor assembly, the driver being movable along an axis, the motor assembly including an output member and a pinch member, wherein the motor assembly includes a motor; operating the motor assembly to move the output member; determining a kinetic energy level of the moving output member based on a rotational speed of an element in the motor assembly, the kinetic energy level of the moving output member being determined as a function of the back electromotive force produced by the motor; and moving the pinch member to drive the driver into contact with the output member to transmit power from the output member to the driver if the kinetic energy level exceeds a predetermined threshold; wherein determining a kinetic energy level of the moving output member includes: determining a temperature of at least a portion of the driving tool; and determining an approximated speed of the motor based at least partially on the back electromotive force and the temperature.