US3824743A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Machine tool control system
Assignee: Landis Tool Co
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Filing: 1973-05-22
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Granted: 1974-07-23
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Expires: 1993-05-22
Abstract
Abstract A machine tool control system moves a grinding wheel from a retracted position to a forward position by applying hydraulic fluid to a hydraulic cylinder to effect a rapid forward movement of the grinding wheel whereupon further movement of the grinding wheel to a final position is effected by supplying a predetermined number of pulses to a stepping motor for driving a feed screw in accordance with a predetermined sequence of grinding movements. The actual advancement of the grinding wheel is monitored by an absolute multiturn encoder rotatably associated with the feed screw and producing a signal which is compared to a combined signal representative of the desired size of the workpiece in the range of grinding. With each grinding sequence, the portion of the feed range signal is reduced to create a difference from a signal produced by the encoder so as to operate a sequence controller to effect advancement of the grinding wheel by supplying pulses to a stepping motor drive circuit connected to controlling relation with a stepping motor connected to a feed screw through a gear train. When the workpiece is ground to the desired size, the sequence controller operates to reversely rotate the stepping motor and reverse the application of hydraulic fluid to return the grinding wheel to a retracted position. The desired size of the workpiece and the advancement of the grinding wheel under the control of the encoder are displayed by suitable gauges on a display panel. The mechanical relation of the encoder to the grinding wheel may be calibrated by a calibration offset signal for increasing or decreasing the signal produced by the encoder indicating the position of the grinding wheel. To enable the actual position of the grinding wheel to be varied without disturbing the relationship between the encoder and the stepping motor in associated circuitry, the feed screw is driven through a gear train including a differential. The encoder is associated with the input gear of the differential while a compensating motor and associated circuitry are provided for rotating the output gear of the differential without effecting the rotational movement of the encoder.
Inventors
- 👤 R Price
- 👤 S Schoonover
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:10
CPC Classifications
G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/416; G05B19/4166; B; B24; B24B; B24B47/00; B24B47/20; G05B2219/00; G05B2219/30; G05B2219/41; G05B2219/41309; G05B2219/41326; G05B2219/41361; G05B2219/43; G05B2219/43152; G05B2219/45; G05B2219/45159; G05B2219/45161; G05B2219/50; G05B2219/50313
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
350 words
In a grinding machine having a grinding wheel supported for slidable movement relative to a workpiece, a hydraulic system for slidably advancing the grinding wheel from a retracted position to a forward position, and a feed screw rotatably driven by a stepping motor under the control of a stepping motor control circuit for advancing the grinding wheel from the forward position to a final position in a predetermined sequence of grinding movements to grind the workpiece to a desired size, the improvement comprising: an adjustable desired size switch providing a binary decimal signal representative of the desired size of the workpiece, a plurality of adjustable feed range switches each providing selectively adjustable binary decimal signals representative of the advancement of the grinding wheel during a corresponding grinding sequence to grind the workpiece to the desired size, an adder for receiving the signals from said desired size switch and from said plurality of feed range switches to produce an output signal representative of the total of the combined signals, an absolute multiturn encoder rotatably associated with said feed screw for producing a binary decimal signal representative of the actual position of said grinding wheel relative to the workpiece, a comparator circuit for receiving and comparing the signals from said adder and said encoder and being operable in response to a difference between the compared signals for producing an output signal representative of the difference between the actual position and the programmed position of said grinding wheel, a sequence controller operable in response to the output signal from said comparator circuit for operating said stepping motor control circuit to move the grinding wheel to a position to equalize the signals from said adder and said absolute encoder, and said sequence controller being operable to sequentially remove from said adder the signals produced by said plurality of adjustable feed range switches to cause successive differences between the signal provided by said adder and the signal provided by said absolute encoder to sequentially advance said grinding wheel to grind the workpiece to the size represented by the signal from said adjustable desired size switch.
Claim 2
Dependent Claim
350 words
In a grinding machine having a grinding wheel supported for slidable movement relative to a workpiece, a hydraulic system for slidably advancing the grinding wheel from a retracted position to a forward position, and a feed screw rotatably driven by a stepping motor under the control of a stepping motor control circuit for advancing the grinding wheel from the forward position to a final position in a predetermined sequence of grinding movements to grind the workpiece to a desired size, the improvement comprising: an adjustable desired size switch providing a binary decimal signal representative of the desired size of the workpiece, a plurality of adjustable feed range switches each providing selectively adjustable binary decimal signals representative of the advancement of the grinding wheel during a corresponding grinding sequence to grind the workpiece to the desired size, an adder for receiving the signals from said desired size switch and from said plurality of feed range switches to produce an output signal representative of the total of the combined signals, an absolute multiturn encoder rotatably associated with said feed screw for producing a binary decimal signal representative of the actual position of said grinding wheel relative to the workpiece, a comparator circuit for receiving and comparing the signals from said adder and said encoder and being operable in response to a difference between the compared signals for producing an output signal representative of the difference between the actual position and the programmed position of said grinding wheel, a sequence controller operable in response to the output signal from said comparator circuit for operating said stepping motor control circuit to move the grinding wheel to a position to equalize the signals from said adder and said absolute encoder, and said sequence controller being operable to sequentially remove from said adder the signals produced by said plurality of adjustable feed range switches to cause successive differences between the signal provided by said adder and the signal provided by said absolute encoder to sequentially advance said grinding wheel to grind the workpiece to the size represented by the signal from said adjustable desired size switch.
Claim 3
Dependent Claim
95 words
In a grinding machine according to claim 1, the combination further comprising: an offset adder for receiving the signal from said absolute encoder and supplying a corresponding output signal to said comparator circuit, an adjustable calibration offset switch for producing a selectively adjustable binary decimal signal representative of a measured position of the grinding wheel and the signal being produced by said absolute encoder, and said offset adder being operable in response to receipt of the sigNal from said adjustable calibration offset switch for varying the corresponding encoder signal being supplied to said comparator circuit.
Claim 4
Dependent Claim
117 words
In a grinding machine according to claim 1, the combination further comprising: a differential gear arrangement having an output gear connected to said feed screw and an input gear driven by said stepping motor, said encoder being connected to said input gear for rotational movement therewith to vary the signal representative of the actual position of said grinding wheel, a compensating stepping motor for driving said output gear of said differential gear arrangement to move said grinding wheel independently of said absolute encoder, and a compensating motor control circuit for operating said compensating motor to move said grinding wheel independently of the signals from said adjustable desired size switch and said plurality of programmable feed range switches.
Claim 5
Dependent Claim
95 words
In a grinding machine according to claim 1, the combination further comprising: a feed adder operable in response to receipt of the signal representative of the desired size of the workpiece from said desired size switch and the signal representative of the position of the grinding wheel from said absolute encoder for producing a resultant difference signal representative of the advancement of the grinding wheel, and a range display gauge operable in response to the resultant difference signal from said feeder adder to provide a visual indication of the feeding movement of the grinding wheel.
Claim 6
Dependent Claim
187 words
In a grinding machine according to claim 1, the combination further comprising: a desired size adder operable in response to receipt of the signal representative of the position of the grinding wheel from said absolute encoder and the signal representative of the range of advancement of the grinding wheel from said plurality of feed range switches to produce a resultant difference signal representative of the desired size of the workpiece, a desired size display gauge operable in response to the resultant difference signal from said desired size adder to provide a visual indication of the desired size of the workpiece, a latch circuit for receiving the signal from said desired adder at the beginning of a grinding operation and supplying the signal to said desired size display gauge, said latching circuit being operable to maintain the desired size signal to the desired size display gauge during the grinding operation, and said latching circuit being operable to an actuating signal from the sequence controller upon the completion of a grinding operation for enabling another resultant difference signal from said desired size adder to said desired size display gauge.
Claim 7
Dependent Claim
112 words
A machine tool comprising a grinding wheel having a radius which decreases with use, and means for precisely and repetitively radially displacing said grinding wheel towards a workpiece to beground so that the peripheral portion of said grinding wheel radially proximate the workpiece will be displaced from an initial non-constant position to a final predetermined position, including an encoder adapted to produce a digital representation of the actual position of the radially proximate peripheral portion intermediate said final predetermined position and a second predetermined position, and means for selectively displacing said radially proximate peripheral position from said non-constant position to said second predetermined position without changing the digital representation of said encoder.
Claim 8
Dependent Claim
112 words
A machine tool comprising a grinding wheel having a radius which decreases with use, and means for precisely and repetitively radially displacing said grinding wheel towards a workpiece to beground so that the peripheral portion of said grinding wheel radially proximate the workpiece will be displaced from an initial non-constant position to a final predetermined position, including an encoder adapted to produce a digital representation of the actual position of the radially proximate peripheral portion intermediate said final predetermined position and a second predetermined position, and means for selectively displacing said radially proximate peripheral position from said non-constant position to said second predetermined position without changing the digital representation of said encoder.
References Cited (Backward Citations)
US3557995A
Cited
US3694970A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |