Automatic-control electronic apparatus for machine tools including provision for zero offset

Claim 2

Apparatus for automatic control of machine tools comprising: a stationary member, a movable member transversely movable toward and away from said stationary member, stepping motor means for supplying the motive power to said movable member, means for generating electrical pulses, the output of which is coupled to said stepping motor and frequency generator means for providing said pulses with predetermined frequencies, said frequency generator means having first and second oscillators generating different frequencies, said first oscillator causing said motor to move said movable member during a roughing-out operation, said second oscillator causing said stepping motor to move said member during a finishing operation with a speed slower than the speed of the roughing-out operation.

Claim 3

Apparatus for automatic control of machine tools comprising: a stationary member, a movable member traNsversely movable toward and away from said stationary member, moving means for moving said movable member in a rapid stroke, stepping motor means for providing the motive power to said movable member, means for generating electrical pulses, the output of which is coupled to said stepping motor, first and second oscillators for generating said pulses at different frequencies, said first oscillator causing said stepping motor to move said movable member in a roughing-out operation, said second oscillator causing said stepping motor to move said member in a finishing operation, first manually operable setting means for setting a first number of pulses corresponding to the thickness of the material to be removed from a workpiece during said roughing-out operation, second manually operable setting means for setting a second number of pulses corresponding to the thickness of material to be removed from the workpiece during said finishing operation, comparing means for comparing said first and second number of pulses with the pulses generated by said first and second oscillator and for generating a coincidence signal when said first number of pulses is reached and a second coincidence signal when said second number of pulses is reached, first means responsive to said first coincidence signal to disable the first oscillator and to activate the second oscillator and second means responsive to said second coincidence signal to disable the second oscillator.

Claim 4

Apparatus for automatic control of machine tools comprising: a stationary member, a movable member traNsversely movable toward and away from said stationary member, moving means for moving said movable member in a rapid stroke, stepping motor means for providing the motive power to said movable member, means for generating electrical pulses, the output of which is coupled to said stepping motor, first and second oscillators for generating said pulses at different frequencies, said first oscillator causing said stepping motor to move said movable member in a roughing-out operation, said second oscillator causing said stepping motor to move said member in a finishing operation, first manually operable setting means for setting a first number of pulses corresponding to the thickness of the material to be removed from a workpiece during said roughing-out operation, second manually operable setting means for setting a second number of pulses corresponding to the thickness of material to be removed from the workpiece during said finishing operation, comparing means for comparing said first and second number of pulses with the pulses generated by said first and second oscillator and for generating a coincidence signal when said first number of pulses is reached and a second coincidence signal when said second number of pulses is reached, first means responsive to said first coincidence signal to disable the first oscillator and to activate the second oscillator and second means responsive to said second coincidence signal to disable the second oscillator.

Claim 5

Apparatus as defined in claim 2, further comprising: third oscillator means activated by said second coincidence signal for generating pulses at a frequency higher than the frequencies of said first and second oscillators and driving means connected to said third oscillator for driving the rotation of said motor in the direction opposite to that in which said motor is rotated in said finishing operation for bringing said movable member back to a resetting position.

Claim 6

Apparatus as defined in claim 3, further comprising: timing circuit means for activating said third oscillator with a predetermined delay for maintaining in contact a tool mounted on said movable member with the workpiece for high finishing of the surface of said workpiece.

Claim 7

Apparatus as claimed in claim 2 further comprising: timing circuit means for activating said first oscillator after a delay time shorter than, or equal to, the time required for said moving means to move said movable member to the position of the end of the forward stroke.

Claim 8

Apparatus as defined in claim 4 further comprising: servomechanism means which actuates a rapid return stroke of the movable member, said servomechanism being activated by said timing means.

Claim 9

Apparatus as defined in claim 4 wherein said workpiece has different radial sizes and further comprising: fourth oscillator means for supplying pulses to said stepping motor during a short approaching stroke of said movable member to said stationary member for bringing said tool in contact with said workpiece.

Claim 10

Apparatus as defined in claim 6 further comprising: transducer means arranged for generating a contact signal when said tool comes into contact with said workpiece for disabling the fourth oscillator.

Claim 11

Apparatus as defined in claim 8 wherein said contact signal is also sent to said first oscillator in order to activate the same, thereby to start a working cycle.

Claim 12

Apparatus for automatic control of machine tools, comprising: a stationary member mounting a workpiece having at least a pair of cylindrical portions to be machined, a movable member mounting a tool for machining said workpiece, said movable member being transversely and longitudinally movable with respect to said stationary member, stepping motor means for providing the motive power to said movable member and for moving transversely said movable member, moving means adapted to be activated for longitudinally Moving said movable member, means for generating electrical pulses to be provided to said stepping motor, first and second oscillators for generating said pulses at different frequencies, said first oscillator causing said stepping motor to move said movable member in a roughing-out operation and said second oscillator causing said stepping motor to move said member in a finishing operation, a third oscillator for generating said pulses at a variable frequency, said third oscillator being adjustable for increasing and decreasing the frequency output thereof, first manually operable setting means for setting a first number of pulses corresponding to the thickness of the material to be removed from a workpiece during said roughing-out operation, second manually operable setting means for setting a second number of pulses corresponding to the thickness of the material to be removed from the workpiece during said finishing operation, third manually operable setting means for setting a third number of pulses corresponding to the difference between said cylindrical portions, comparing means for comparing said first and second number of pulses with the pulses generated by said first and second oscillator and for generating a first coincidence signal when said first number of pulses is reached, a second coincidence signal when said second number of pulses is reached and a third coincidence signal when said third number of pulses is reached, first means responsive to said first coincidence signal to disable said first oscillator and to activate said second oscillator and second means responsive to said second coincidence signal to disable said second oscillator, said second coincidence signal activating said moving means for operating same to bring said tool in correspondence with the second portion of said pair of portions and adjusting said oscillator to increase the frequency of the pulses, said third coincidence signal causing said third oscillator to be disabled and said first oscillator to be activated as to start a working cycle on the second cylindrical portion of said pair.

Claim 13

Apparatus for automatic control of machine tools, comprising: a stationary member mounting a workpiece having at least a pair of cylindrical portions to be machined, a movable member mounting a tool for machining said workpiece, said movable member being transversely and longitudinally movable with respect to said stationary member, stepping motor means for providing the motive power to said movable member and for moving transversely said movable member, moving means adapted to be activated for longitudinally Moving said movable member, means for generating electrical pulses to be provided to said stepping motor, first and second oscillators for generating said pulses at different frequencies, said first oscillator causing said stepping motor to move said movable member in a roughing-out operation and said second oscillator causing said stepping motor to move said member in a finishing operation, a third oscillator for generating said pulses at a variable frequency, said third oscillator being adjustable for increasing and decreasing the frequency output thereof, first manually operable setting means for setting a first number of pulses corresponding to the thickness of the material to be removed from a workpiece during said roughing-out operation, second manually operable setting means for setting a second number of pulses corresponding to the thickness of the material to be removed from the workpiece during said finishing operation, third manually operable setting means for setting a third number of pulses corresponding to the difference between said cylindrical portions, comparing means for comparing said first and second number of pulses with the pulses generated by said first and second oscillator and for generating a first coincidence signal when said first number of pulses is reached, a second coincidence signal when said second number of pulses is reached and a third coincidence signal when said third number of pulses is reached, first means responsive to said first coincidence signal to disable said first oscillator and to activate said second oscillator and second means responsive to said second coincidence signal to disable said second oscillator, said second coincidence signal activating said moving means for operating same to bring said tool in correspondence with the second portion of said pair of portions and adjusting said oscillator to increase the frequency of the pulses, said third coincidence signal causing said third oscillator to be disabled and said first oscillator to be activated as to start a working cycle on the second cylindrical portion of said pair.

Claim 14

Apparatus as defined in claim 10, wherein said comparing means is so arranged as to generate a fourth coincidence signal when the pulses generated by said third oscillator differ from said third number by a predetermined amount, said fourth coincidence signal conditioning said third generator to decrease the frequency of the pulses.