| 摘要 |
PURPOSE:To facilitate discharging of a cutting chip even in the case of working the thick body to be worked, by energizing a feeding motor periodically during punching by a drill device, and braking the feeding motor at the stoppage of the current supply. CONSTITUTION:There are provided a feeding motor 13 feeding a drill motor 9 in the direction of a workpiece and an electromagnet 5 for attracting a drill device to the workpiece. The load of this drill motor 9 is detected by a load detection circuit 10. Also, on this device there are provided an oscillation circuit 57 repeating the outputs of H and L at the specific cycle and an electrification control means intermittently electrifying the motor 13 according to the output of this oscillation circuit 57. Moreover, a brake circuit 59 is provided to short- circuit the space between the power source terminals of the motor 13 at the time when the electrification onto the motor 13 is stopped. Furthermore, a voltage reduction means is provided to reduce the feeding voltage to the motor 13 in case of the motor 9 being in a no load state. Also, the voltage of the reactuation time of the motor 13 is made higher than the normal. |
