Mechanical peck drill

An apparatus for reciprocating a tool in a workpiece comprising:

• a rotator connected to the tool to rotate the tool about the longitudinal axis of the tool, said rotator comprising a first gear, said first gear being slidably mounted to a spindle;
• a mechanical reciprocator connected to the tool for cyclically reciprocating the tool into the workpiece and at least partially withdrawing the tool from the workpiece for a plurality of cycles, said mechanical reciprocator comprising a second gear threaded to the spindle;
• a third gear connected to said first gear;
• a fourth gear connected to said second gear;
• a first drive train comprising a first motor connected to said third gear;
• a second drive train comprising a second motor connected to said fourth gear;
• and
• a shifter, said shifter being connected to said fourth gear.

A circuit for controlling the operation of an apparatus, the apparatus including:

• a spindle adapted to hold a drill bit, said spindle having connected thereto a first indicator, a second indicator, a third indicator, a spindle feed gear, and a spindle rotation gear, said spindle rotation gear being slidably mounted on said spindle, said spindle feed gear being threaded on said spindle and having an advance direction of rotation and a retract direction of rotation,
• a differential rotation gear engaging said spindle rotation gear,
• a differential feed gear engaging said spindle feed gear and said differential rotation gear when shifted into a drilling mode position,
• said differential feed gear engaging said spindle feed gear and being disengaged from said differential rotation gear when shifted into a non-drilling mode position,
• a rotation drive train engaging the differential feed gear;
• and
• a feed drive train engaging the differential feed gear when the differential feed gear is disengaged from the differential rotation gear;
• said circuit comprising:
• a drilling mode sensor which generates a drilling mode signal when contacted by the first indicator on the spindle;
• a shifter which moves the differential feed gear into and out from engagement with the differential rotation gear, said shifter, in response to said drilling mode signal, engaging the differential feed gear with the differential rotation gear and disengaging the differential feed gear from the feed drive train;
• a timer, started in response to said drilling mode signal, said timer generating a time signal at the end of a predetermined time,
• the shifter, in response to said time signal, disengaging the differential feed gear from the differential rotation gear and engaging the differential feed gear with the feed drive train,
• the feed drive train, in response to said time signal, turning the differential feed gear in the retract direction,
• a retracted position sensor which generates a retracted signal when contacted by the second indicator on the spindle,
• the feed drive train, in response to said retracted signal, reversing the direction of the differential feed gear and turning the differential feed gear in the advance direction until said drilling mode sensor is contacted by the first indicator on the spindle;
• an end of hole sensor which generates an end of hole signal when contacted by the third indicator on the spindle,
• the shifter, in response to said end of hole signal, disengaging the differential feed gear from the differential rotation gear and engaging the differential feed gear with the feed drive train,
• the feed drive train, in response to said end of hole signal, turning the differential feed gear in the retract direction,
• a job done sensor which generates a job done signal when sensing said end of hole signal and being contacted by the third indicator on the spindle,
• the rotation drive train stopping in response to said job done signal, and
• the feed drive train stopping in response to said job done signal.