Electric discharge machine with a program copier and a tool support head carried by a longitudinally and transversely driven carriage

Claim 1

A metal-cutting machine comprising a base; a table mounted on said base for clamping a workpiece thereon; longitudinal ways on said base; a main carriage mounted on said longitudinal ways for longitudinal displacement thereon, said main carriage being provided with transverse ways; a cross-slide mounted in the transverse ways of said main carriage; a power head with cutting tool mounted on said cross-slide; first and second drive means for respectively driving said main carriage and cross-slide with respect to their associated ways, said second drive means being mounted on said main carriage adjacent to said main carriage; a program-copying device connected to said first and second drive means to control the same and thereby the driving of the main carriage and cross-slide, said longitudinal ways comprising a horizontal longitudinal guide-bar extending through a longitudinal passage provided in said main carriage and having ends fixed to said base, said transverse ways being constituted by a transverse passage provided in the main carriage with its axis horizontal and in a plane perpendicular to the axis of said longitudinal passage in the main carriage, said cross-slide including a horizontal cross guide-bar displaceably mounted in said transverse passage and having one end secured to said power head, a cross-arm secured to the other end of said cross guide-bar and extending perpendicularly to the axis of said cross guide-bar and means operatively coupling said cross-arm to said second drive means for the cross-slide comprising a screw-and-nut drive including a drive motor, means slidably mounting said drive motor on said main carriage for travel parallel to said cross guide-bar, a screw arranged parallel to the axis of the cross guide-bar with one of its ends drivingly connected to said drive motor, said screw being located on the main carriage on the same side of the cross-arm as the cross guide-bar, and a nut fixed in position on the cross-arm and engaged by said screw, said drive motor of the second drive means being superimposed above said cross guide-bar at an intermediate location along the length thereof and also above said longitudinal ways on said base and being confined within the outline of the carriage, said screw extending the length from the drive motor of the second drive means to said cross arm which represents only a portion of the length of said cross guide-bar.