Abstract: The drilling machine has a cross member along which slide two carriages supporting two machining heads; the two carriages are moved independently of each other along the X axis; one of the two machining heads is fitted to the respective carriage by means of a slide which is also moved along the Y axis by an electric motor controlled by a numeric-control unit; the maximum travel of the slide is at least twice the pitch of the rows in the matrix of holes in the printed circuit boards; and the movement of the slide provides for both setting the two machining heads along the Y axis, and enabling the two machining heads to simultaneously drill two adjacent rows in the matrix of holes.

Abstract: The drilling unit comprises a cross-piece secured to the base and two carriages supporting said two operating heads and sliding on said cross-piece. The two carriages are each displaced independently of one another along the axis by means of two nut and screw pairs, each of which is associated with one of the carriages. The screw of each nut and screw pairs is actuated by a corresponding reversible electric motor mounted on the cross-piece, whereas the nut is mounted on the corresponding carriage displaced outwards with respect to the head so as to allow the heads to move individually into a common machining zone on the table.

Abstract: A machining head presenting a hollow body in turn presenting a first crosspiece with a seat for supporting in sliding manner a motor-driven tool spindle. The body also presents a second crosspiece fitted with means for axially displacing the spindle which may be of different lengths and is driven by an electric motor via a screw-nut screw pair located between the second crosspiece and a third crosspiece connected removably to the spindle. The second crosspiece presents an end portion pivoting by means of a pin on an appendix of the hollow body, and is fitted to the body by means of a pair of locating pins and a pair of screws. By disconnecting the third crosspiece from the spindle and rotating the second crosspiece about the pin, the spindle may be changed without removing the machining head from the machine. The locating pins are removed from their respective seats by means of a key in the form of a screw and normally housed in a seat on the crosspiece.