Control device for boring machine

A drill controlling apparatus for a machine, the machine having a drill driven by an electric motor, a frame supporting the drill for vertical movement, and an electromagnet for anchoring the frame, comprising:

• a fault examining means for generating a fault signal when a magnitude of a current supplied to the electromagnet is not within a predetermined allowable range;
• an energization inhibiting means responsive to the fault signal for inhibiting energization of the motor;
• a first switch for supplying electric power to the electromagnet;
• a second switch for supplying electric power to the motor;
• and,
• a second energization inhibiting means for inhibiting energization of the motor when electric power is supplied simultaneously through both the first and the second switches for starting to supply the electric power to the electromagnet and the motor.

A drill controlling apparatus for a machine, the machine having a drill driven by an electric motor, a frame supporting the drill for vertical movement, and an electromagnet energizable for anchoring the frame, comprising:

• a normally open relay contact connected in series to the motor;
• a relay for actuating the normally open relay contact;
• a first switching element connected in series with the relay;
• an energization inhibiting means for inhibiting energization of the relay when the first switching element closes to connect a power source to the relay less than a predetermined time of delay after the electromagnet is energized;
• and
• a release means for releasing the energization inhibiting means to start the electric motor when the first switching element is closed after the electromagnet has been energized and the electromagnet has been energized for the predetermined time of delay.