US3886424A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system having actual backlash compensating apparatus
Assignee: Toshiba Corp
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Filing: 1972-03-14
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Granted: 1975-05-27
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Expires: 1992-03-14
Abstract
Abstract An actual backlash compensating apparatus for a screw driven system includes a worktable, a drive screw, a nut and a drive unit for driving the worktable so as to linearly travel in accordance with the drive screw and nut. A rotation angle detector generates a signal corresponding to the angle through which the drive screw is made to rotate. A servo system determines the position of the worktable by comparing the output signal from the rotation angle detector with a predetermined input signal supplied by a numerical controller. A displacement detector is coupled to the worktable for detecting errors in the positioning thereof caused by backlash between the starting position of the worktable and the driver screw. The signal from the displacement detector is applied to a differential amplifier along with the signal determined by the servo system such that any backlash referred to above is eliminated. Additionally one or more axis displacement detectors are provided for eliminating any backlash due to the axis position of the drive screw.
Inventors
- 👤 Naomi Hoshina
- 👤 Etsuji Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:18
CPC Classifications
G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/19; G05B19/21; G05B19/23; G05B19/231; G05D; G05D3/00; G05D3/12; G05D3/20; G05B2219/00; G05B2219/30; G05B2219/41; G05B2219/41068
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
163 words
A backlash compensating apparatus for a screw driven system comprising: a worktable, a drive screw, a nut, a drive unit for driving said worktable so as to linearly travel in accordance with said drive screw and said nut, rotation angle detecting means for generating a signal corresponding to the angle through which said drive screw is made to rotate by said drive unit, a servo system for determining the position of the worktable by collating said output signal from said rotation angle detecting means with a predetermined input value, a displacement detector coupled to said worktable to directly mechanically detect a position of said drive screw relative to a position of said worktable to thereby detect errors in the positioning thereof caused by backlash between a starting position of said worktable and a starting position of said drive screw, and means for correcting said backlash in accordance with output signals from said displacement detector by correcting the input signals to said drive unit.
Claim 2
Dependent Claim
163 words
A backlash compensating apparatus for a screw driven system comprising: a worktable, a drive screw, a nut, a drive unit for driving said worktable so as to linearly travel in accordance with said drive screw and said nut, rotation angle detecting means for generating a signal corresponding to the angle through which said drive screw is made to rotate by said drive unit, a servo system for determining the position of the worktable by collating said output signal from said rotation angle detecting means with a predetermined input value, a displacement detector coupled to said worktable to directly mechanically detect a position of said drive screw relative to a position of said worktable to thereby detect errors in the positioning thereof caused by backlash between a starting position of said worktable and a starting position of said drive screw, and means for correcting said backlash in accordance with output signals from said displacement detector by correcting the input signals to said drive unit.
Claim 3
Dependent Claim
98 words
A backlash compensating apparatus for a screw driven system as defined in claim 1, wherein said servo system comprises: an error register adapted to receive signals which denote a difference between the value of the output from said rotation angle detecting means and the predetermined input value, and to generate a digital output signal corresponding thereto, a digital-to-analog converter for converting the output signal from said error register into a corresponding analog value, and a differential amplifier connected to said converter and said displacement detector so as to actuate said drive unit according to the resultant output thereof.
Claim 4
Dependent Claim
110 words
A backlash compensating apparatus for a screw driven system as defined in claim 1 wherein said servo system comprises: an analog-to-digital converter for converting said output signals from said displacement detector which are of analog type into corresponding digital signals, an error register adapted to receive a digital signal obtained by collating the output from said analog-to-digital converter with said previous collating which was obtained from the output signal of said rotation angle detector and said prescribed input value, and a digital-to-analog converter for converting said digital signal from said error register into a corresponding analog signal so as to actuate said drive unit according to the resultant output thereof.
Claim 5
Dependent Claim
40 words
A backlash compensating apparatus for a screw driven system as defined in claim 1, wherein said displacement detector is an electric micrometer which is provided with a contact member having a contactor which makes direct contact with said drive screw.
Claim 6
Dependent Claim
72 words
A backlash compensating apparatus for a screw driven system as defined in claim 1, which further comprises: a flange on an axis of said drive screw; and, an axis displacement detector member having a contactor which makes contact with a flank of said flange, said axis displacement detector being coupled to a bearing portion of said drive screw so as to detect any errorS in the axis position of said drive screw.
Claim 7
Dependent Claim
44 words
A backlash compensating apparatus for a screw driven system as defined in claim 5, which comprises another axis displacement detector which is coupled on said bearing portion of said drive screw axis, said two axis displacement detectors being respectively coupled on opposite sides thereof.
Claim 8
Dependent Claim
187 words
A backlash compensating apparatus for a screw driven system, which comprises: a worktable, a drive nut rigidly connected to said worktable, a drive screw cooperatively engaged with said drive nut; control means for generating a control signal indicative of the desired movement of said worktable; a drive unit for linearly driving said drive screw in response to said control signal received from said control means; rotation angle detecting means for generating a signal corresponding to the angle through which said drive screw is made to rotate by said drive unit; a servo system for determining the position of said worktable by collating said signal generated by said rotation angle detecting means with said control signal; a displacement detector coupled to said worktable to directly detect a position of said drive screw relative to a position of said worktable to thereby detect errors in the positioning thereof caused by backlash between a starting position of said worktable and a starting position of said drive screw; and means for correcting said backlash by comparing the output signal from said displacement detector with said collated signal of said servo system.
Claim 9
Dependent Claim
187 words
A backlash compensating apparatus for a screw driven system, which comprises: a worktable, a drive nut rigidly connected to said worktable, a drive screw cooperatively engaged with said drive nut; control means for generating a control signal indicative of the desired movement of said worktable; a drive unit for linearly driving said drive screw in response to said control signal received from said control means; rotation angle detecting means for generating a signal corresponding to the angle through which said drive screw is made to rotate by said drive unit; a servo system for determining the position of said worktable by collating said signal generated by said rotation angle detecting means with said control signal; a displacement detector coupled to said worktable to directly detect a position of said drive screw relative to a position of said worktable to thereby detect errors in the positioning thereof caused by backlash between a starting position of said worktable and a starting position of said drive screw; and means for correcting said backlash by comparing the output signal from said displacement detector with said collated signal of said servo system.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-26 | 1978-11-25 | 1979-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-26 | 1982-11-25 | 1983-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-26 | 1986-11-25 | 1987-05-27 | $7700.00 | Window Closed / Lapsed |