| 摘要 |
PURPOSE:To perform a safe cutting work, by a method wherein a state in which drive torque is decreased during transfer of drive torque from an unstable region to a stable region can be displayed. CONSTITUTION:When it is decided that drive torque exerted on a transmission spring serving as a rotation transmission member does not enter a stable region, a CPU 3 executes computation to determine the decrease factor of drive torque. Based on a calculated decrease factor, a display control signal is outputted to a display drive circuit 43 to light, in order from the display unit 42a side, only by the number of display units, equivalent to a decrease factor, of ten display units 42a-42j. Thus, only by observing the number of the lighted display units, a worker detects that present drive torque is decreased to what degree. When the decrease value of drive torque is decreased to a value lower than a torque reference value, the CPU 31 outputs a movement control signal to a valve drive circuit 41 to switch a solenoid valve 13 for control, and a drill is moved to a machining position. This constitution enables safe starting of a cutting work. |
