System for adapting an automatic screw machine to achieve computer numeric control

A cam controlled machine adapted for computer numeric control, comprising:

• a tool slide trajectory design subsystem for developing a specified tool trajectory, which trajectory is a locus of positions;
• a camshaft position monitor, said camshaft conventionally operable to actuate said cam;
• a position transformer which determines a desired tool position as a direct function of current machine cycle position, on a substantially continuous basis;
• an actuator in physical relationship with the tool;
• and
• a feedback control subsystem which monitors the position of the tool and commands the actuator so as to cause the tool to follow the specific tool trajectory.

A method for adapting a single-spindle automatic screw machine to operate by computer numeric control (CNC), the method comprising the steps of:

• removing a cam from said machine, said cam being conventionally functionable to actuate a tool slide;
• specifying a tool slide trajectory, and thereby designing a software based cam, said trajectory comprising a locus of desired turret slide positions;
• controlling the operation of the machine with said software based cam;
• monitoring a machine cycle position by directly or indirectly monitoring the position of a camshaft;
• determining a desired tool slide position as a direct function of said machine cycle position, on a substantially continuous basis;
• and
• causing said tool slide to achieve said desired tool slide position along said specified tool slide trajectory by installing a servo actuator in place of said cam.

A system for adapting a conventional, non-computer-numeric-controlled, single-spindle automatic screw machine to accept computer numerical control, wherein the system comprises:

• an existing turret slide on said screw machine;
• a lead lever adapted to contact said turret slide;
• a camshaft mounted on said screw machine;
• a mechanical drive unit mounted to said screw machine in lieu of a conventional hard cam, said mechanical drive unit having at least one bearing through which said camshaft passes, said mechanical drive unit adapted to contact said lead lever, directly or indirectly;
• a device for measuring the rotational position of said camshaft;
• a position transformer which determines a desired turret slide position as a user specified direct function of said camshaft rotational position on a substantially continuous basis;
• and
• a computer-numeric-controlled actuator, responsive to said transformer, that causes said mechanical drive unit to move said turret slide to said desired turret slide position.

A method for adapting a single-spindle automatic screw machine to operate by computer numeric control, the method comprising the steps of:

• installing a mechanical drive unit on said screw machine directly in place of a conventional hard cam, said drive unit adapted to contact, directly or indirectly, a lead lever on said screw machine;
• installing a camshaft rotational position detector in association with said screw machine
• installing a computer-numeric-controlled actuator in association with said mechanical drive unit;
• detecting the rotational position of a camshaft on said screw machine during operation of said screw machine;
• substantially continuously computing a desired position of the existing turret slide on said screw machine as a user specified direct function of the rotational position of said camshaft;
• and
• actuating said mechanical drive unit to cause said lead lever to move said turret slide into said desired position.

A system for adapting a conventional, non-computer-numeric-controlled, single-spindle automatic screw machine, having a camshaft, a cam follower and a tool slide, to accept computer numeric control of said tool slide, wherein the system comprises:

• a tool slide trajectory designer that generates a tool slide trajectory, given an operator-specified sequence of tool motions, said tool slide trajectory comprising a locus of tool slide positions as a direct function of camshaft angular position;
• a monitor for directly or indirectly determining the current camshaft angular position;
• a computer based position transformer that determines a desired tool slide position from said tool slide trajectory as a direct function of said camshaft angular position on a substantially continuous basis;
• and
• a position controller that causes said tool slide to substantially continuously achieve said desired tool slide position, said position controller incorporating an actuator unit as a direct physical replacement for the conventional cam, said actuator unit mounting to the camshaft via a rotary bearing and directly actuating the cam follower, which in turn actuates the tool slide.

A system for adapting a conventional, non-computer-numeric-controlled, single-spindle automatic screw machine, having a camshaft and a tool slide, to accept computer numeric control of said tool slide, wherein the system comprises:

• a tool slide trajectory design subsystem that generates a tool slide trajectory, given an operator-specified sequence of tool motions, said tool slide trajectory comprising a locus of tool slide positions as a direct function of camshaft angular position;
• a monitor for directly or indirectly determining the current camshaft angular position;
• a position transformer that determines a desired tool slide position from said tool slide trajectory as a direct function of said camshaft angular position on a substantially continuous basis;
• and
• a position controller that causes said tool slide to substantially continuously achieve said desired tool slide position.