US3725651A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Numerical control system for a lathe
Assignee: Bendix Corp
•
Filing: 1970-08-05
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Granted: 1973-04-03
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Expires: 1990-08-05
Abstract
Abstract A continuous-path numerical system controls the position of the cutter of a lathe with respect to the workpiece and the rate of rotation of the work spindle in accordance with a series of numerical commands encoded on a punched tape. Each command, in addition to position information, includes information relating to the desired rate of movement of the cutter over the workpiece in surface feet per minute and the desired rate of advancement of the cutter in terms of inches per revolution. The commands controlling the position of the cutter with respect to the center line of the spindle are continuously monitored and the quantity representative of the commanded separation is divided into the programmed surface feet-per-minute number to derive a number used to control the spindle motor drive. This system additionally calculates a feedrate number based on the incremental distances of motion along the X and Z axes called for by a particular command and the inches per revolution number. A pulse train generated by a transducer which senses the rate of rotation of the spindle is multiplied by this feedrate number to derive command pulse trains for DDA-type interpolators which generate control signals for the X and Z axes.
Inventors
- 👤 H Cutler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:03
CPC Classifications
G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/182; G05B19/186; G05B2219/00; G05B2219/30; G05B2219/34; G05B2219/34041; G05B2219/37; G05B2219/37345; G05B2219/43; G05B2219/43141
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
117 words
A control system for a lathe having a rotary spindle and a cutter positionable with respect to said spindle, comprising: a source of numerical information relating to a desired path of motion of the cutter relative to the spindle; a variable speed drive system responsive to said information for the spindle; a drive system for positioning the cutter relative to the spindle; means for generating a control signal which is a function of the distance of the cutter from the axis of rotation of the spindle; and means for providing said control signal to said variable speed spindle drive so as to cause the drive speed to be modified as a function of the said control signal.
Claim 2
Dependent Claim
117 words
A control system for a lathe having a rotary spindle and a cutter positionable with respect to said spindle, comprising: a source of numerical information relating to a desired path of motion of the cutter relative to the spindle; a variable speed drive system responsive to said information for the spindle; a drive system for positioning the cutter relative to the spindle; means for generating a control signal which is a function of the distance of the cutter from the axis of rotation of the spindle; and means for providing said control signal to said variable speed spindle drive so as to cause the drive speed to be modified as a function of the said control signal.
Claim 3
Dependent Claim
74 words
The system of claim 1 wherein said control signal is directly proportional to the distance between the center of rotation of the spindle and the cutter and said variable speed spindle drive is controlled in inverse proportion to said control signal, whereby the rate of travel of the cutter over a workpiece supported on the spindle is maintained constant, independent of the separation of the cutter from the axis of rotation of the spindle.
Claim 4
Dependent Claim
62 words
The system of claim 1 wherein said source of numerical information includes information relating to the desired rate of travel of the cutter over the surface of a workpiece supported on the spindle, and wherein said variable speed spindle drive is controlled as a direct function of the value of said numerical information and as an inverse function of the control signal.
Claim 5
Dependent Claim
113 words
The system of claim 1 wherein said control signal is directly proportional to the distance of the cutter from the center of rotation of the spindle, the system includes a second source of numerical information relating to the desired rate of travel of the cutter over a workpiece supported in the spindle, means are provided for deriving a second control signal from said second numerical information, and said variable speed spindle drive is controlled as a direct function of the value of said second control signal, and as an inverse function of the control signal which is a function of the distance of the cutter from the axis of rotation of the spindle.
Claim 6
Dependent Claim
49 words
The control system of claim 1 wherein said drive system for positioning the cutter is controlled by signals derived from said source of numerical information so that the motion of the cutter along said desired path occurs at a rate proportional to the rate of rotation of the spindle.
Claim 7
Dependent Claim
62 words
The control system of claim 5 wherein said source of numerical information includes information relating to the rate of motion of the cutter and the drive system for positioning the cutter is caused to move at a resultant rate which is a direct function of said last said numerical information and a direct function of the rate of rotation of the spindle.
Claim 8
Dependent Claim
63 words
The system of claim 6 wherein the numerical information relating to the desired path of motion is expressed as a series of increments of motion and control signals for the drive system for positioning the cutter are generated, for each increment, at rates directly proportional to both the rate of rotation of the spindle and the numerical value of the rate control signal.
Claim 9
Dependent Claim
193 words
A control system for a machine having a rotary spindle and a cutter positionable with respect to said spindle, comprising: a source of numerical information relating to a desired path of motion of the cutter with respect to the spindle, such motion being expressed as a series of connected motion segments, the numerical information including information relating to the rate of travel of the cutter over a workpiece supported on the spindle; means for generating a first control signal which is the function of the distance of the cutter from the axis of rotation of the spindle; a variable speed drive system for the spindle; means for controlling said variable speed drive system as a direct function of said numerical inFormation relating to the rate of motion of the cutter over the workpiece supported on the spindle, and in inverse proportion to the said first control signal; means for generating a second control signal proportional to the rate of rotation of the spindle; and means for controlling the motion of the cutter relative to the spindle in accordance with said numerical information and at a rate directly proportional to said second control signs.
Claim 10
Dependent Claim
193 words
A control system for a machine having a rotary spindle and a cutter positionable with respect to said spindle, comprising: a source of numerical information relating to a desired path of motion of the cutter with respect to the spindle, such motion being expressed as a series of connected motion segments, the numerical information including information relating to the rate of travel of the cutter over a workpiece supported on the spindle; means for generating a first control signal which is the function of the distance of the cutter from the axis of rotation of the spindle; a variable speed drive system for the spindle; means for controlling said variable speed drive system as a direct function of said numerical inFormation relating to the rate of motion of the cutter over the workpiece supported on the spindle, and in inverse proportion to the said first control signal; means for generating a second control signal proportional to the rate of rotation of the spindle; and means for controlling the motion of the cutter relative to the spindle in accordance with said numerical information and at a rate directly proportional to said second control signs.
Claim 11
Dependent Claim
92 words
The system of claim 8 wherein the cutter is movable along a pair of axes, one of which is normal to the axis of rotation of the spindle, and the other of which is parallel to the axis of rotation of the spindle, the numerical information relating to each segment of motion includes increments of motion along said two axes, interpolators are provided for each of the axes to generate control signals at rates proportional to the numerical information, and the interpolators are operated at rates proportional to the second control signal.
Claim 12
Dependent Claim
37 words
The system of claim 9 wherein the second control signal consists of a train of pulses generated by a transducer physically connected to spindle and operative to generate a pulse for each incremental rotation of the spindle.
Claim 13
Dependent Claim
63 words
The system of claim 10 wherein the interpolators operate to repeatedly add the numerical information relating to the motion segments along each axis into registers and to generate output pulses as a function of the overflow of said registers, and an addition is made into each of said registers each time a pulse occurs in the train of pulses generated by said transducer.
Claim 14
Dependent Claim
51 words
The system of claim 11 wherein the pulse train output of the transducer is multiplied by numerical information relative to the desired rate of motion of the cutter relative to the spindle axis to develop a second pulse train which is used to control the rate of operation of the interpolators.
Claim 15
Dependent Claim
148 words
A control system for a machine having a rotary spindle and a cutter positionable with respect to such spindle, comprising: a source of numerical information relating to the desired path of motion of the cutter relative to the spindle and the desired rate of travel of the cutter over the surface of a workpiece supported on the spindle; means for rotating the spindle at a rate which is a direct function of the commanded rate of travel of the cutter over the surface of a workpiece supported on the spindle and an inverse function of the normal distance between the cutter and the center of rotation of the spindle; and means for controlling the position of the cutter relative to the spindle so as to move the cutter through the path commanded by said numerical information at a rate proportional to the rate of rotation of the spindle.
Claim 16
Dependent Claim
148 words
A control system for a machine having a rotary spindle and a cutter positionable with respect to such spindle, comprising: a source of numerical information relating to the desired path of motion of the cutter relative to the spindle and the desired rate of travel of the cutter over the surface of a workpiece supported on the spindle; means for rotating the spindle at a rate which is a direct function of the commanded rate of travel of the cutter over the surface of a workpiece supported on the spindle and an inverse function of the normal distance between the cutter and the center of rotation of the spindle; and means for controlling the position of the cutter relative to the spindle so as to move the cutter through the path commanded by said numerical information at a rate proportional to the rate of rotation of the spindle.
Claim 17
Dependent Claim
105 words
The control system of claim 13 wherein the position of the cutter relative to the spindle is controlled by means which includes at least one digital servo operative to move the cutter along an axis normal to the center of rotation of the spindle and the system includes means for generating a train of control pulses from said numerical information for powering said digital servo, and a reversible register operative to receive said train of pulses and to algebraically store them so as to maintain a number proportional to the distance of the cutter from the center of rotation of the spindle along normal lines.
Claim 18
Dependent Claim
48 words
The control system of claim 14 wherein means are provided for presetting the contents of said register with a number proportional to the normal distance between the cutter and the center of rotation of the spindle prior to the initiation of utilization of a section of numerical information.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |