Method and apparatus for electromechanically retro-fitting a conventional automatic screw machine to accept numerical control

A method for retro-fitting a conventional automatic screw machine to accept numerical control, wherein said conventional machine includes a plurality of mechanical timing means which actuate engaging means, such as clutches and gears, which in turn are operative to connect a main driving means to a plurality of operating mechanisms of the machine, one of which controls the spindle speed, another of which controls the indexing of the turret and still another of which controls the feeding of the stock in the spindle, and wherein said conventional machine further includes a plurality of special purpose cam means which are also driven by the main driving means, for controlling the movement of the turret and the cross-slides of the machine, wherein each machining task performed by the conventional machine requires a new plurality of special purpose cam means designed particularly for the task, wherein the method comprises the steps of:

• (a) replacing the existing mechanical timing means for each operating mechanism in the conventional machine with means for actuating the engaging means associated therewith by an electrical signal, without modification of the existing engaging means;
• (b) disconnecting the turret and the cross slides from the main driving means and from the special purpose cam means, so that the turret and the cross slides are actuatable without said drive means and said cam means;
• and
• (c) connecting indivudally electrically actuatable drive means, respectively, to the turret and the cross slides, without modification of the turret and the cross sides, so that the turret and the cross slides are driven by said electrically controlled drive means instead of by said main driving means and said special purpose cam means, thereby eliminating the special purpose cam means otherwise necessary for the operation of the conventional machine.