US3566239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic fine & coarse positioning apparatus by means of numerical control for machine tools and the like
Assignee: Mitsui Seiki Kogyo Co Ltd
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Filing: 1967-07-03
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Granted: 1971-02-23
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Expires: 1987-07-03
Abstract
Abstract Automatic positioning of a workpiece with respect to a machine tool in response to coded numerical command data is provided by a system which uses a pulse motor driving a lead screw to move the workpiece. The pulses driving the motor are counted and compared with the command data in a comparator to determine the remaining distance to the destination and to stop the pulse motor when the destination is reached. A highly accurate scale graduated in millimeters moves with the workpiece and is photoelectrically monitored to produce a scale pulse each time the workpiece moves by a millimeter. The comparator operates a gate to select the scale pulse produced by the last graduation before the destination, and the selected pulse is used to correct the accumulated count of motor-driving pulses, thus to eliminate prior errors. Subsequently, when the accumulated count equals the command data, the comparator stops the motion of the workpiece in the desired final position. The comparator also provides a controlled stepwise decrease in workpiece speed as the scalepulse selection time and the destination are approached. An offset of a fraction of a millimeter is preferably provided for the photoelectric monitoring system to improve accuracy further.
Inventors
- 👤 Masami Taniguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:45
CPC Classifications
G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/19; G05B19/21; G05B19/23; G05B19/238; G05B2219/00; G05B2219/30; G05B2219/41; G05B2219/41092; G05B2219/49; G05B2219/49134
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
444 words
Apparatus for automatically displacing one object with respect to another object, along a predetermined coordinate direction, from a reference position to a destination position comprising: screw means responsive to rotation thereof to move said first object along said direction; pulse motor means responsive to successive driving pulses to rotate said screw means and move said one object along said direction by substantially a predetermined amount in response to each of said pulses in a directional sense determined by a predetermined characteristic of said pulses; a source of driving pulses and means for applying them to said pulse motor means to move said one object, said source being controllable to determine the rate of generation of said pulses and to control said predetermined characteristic of said pulses, thereby to control the rate and directional sense of motion of said one object; counting means responsive to said pulses from said source for accumulating number information in digital form representative of a net count of said pulses, those of said pulses which move said one object in one directional sense being effective to increase said count and those which move said one object in the opposite sense being effective to decrease said count; command-data input means for providing and storing command number information in digital form representative of the magnitude of the desired displacement of said one object from said reference position to said destination position; computer means responsive to said command number information and to said accumulated number information for controlling said source of driving pulses to move said one object to said destination position and for arresting said one object at said destination position; and means for correcting said accumulated number information prior to reaching said destination point thereby more accurately to represent the instantaneous position of said one object as it approaches said destination point, said correcting means comprising indicia means and indicia-sensing means, one fixed with respect to said one object and the other fixed with respect to said other object, said indicia-sensing means producing signals in response to sensing of said indicia, signal gating means responsive to said accumulated number information for selecting a signal from said indicia-sensing means produced by the last one of said indicia sensed prior to reaching said destination point, and means for utilizing said selected signal to correct said accumulated number information, said indicia means comprising an accurate scale member fixed to said one object and said indicia-sensing means comprising optical-photoelectric means for sensing when any of said indicia occupy a predetermined position, said computer means being responsive to said corrected accumulated number information to move said one object to said destination position after said correcting occurs.
Claim 2
Dependent Claim
444 words
Apparatus for automatically displacing one object with respect to another object, along a predetermined coordinate direction, from a reference position to a destination position comprising: screw means responsive to rotation thereof to move said first object along said direction; pulse motor means responsive to successive driving pulses to rotate said screw means and move said one object along said direction by substantially a predetermined amount in response to each of said pulses in a directional sense determined by a predetermined characteristic of said pulses; a source of driving pulses and means for applying them to said pulse motor means to move said one object, said source being controllable to determine the rate of generation of said pulses and to control said predetermined characteristic of said pulses, thereby to control the rate and directional sense of motion of said one object; counting means responsive to said pulses from said source for accumulating number information in digital form representative of a net count of said pulses, those of said pulses which move said one object in one directional sense being effective to increase said count and those which move said one object in the opposite sense being effective to decrease said count; command-data input means for providing and storing command number information in digital form representative of the magnitude of the desired displacement of said one object from said reference position to said destination position; computer means responsive to said command number information and to said accumulated number information for controlling said source of driving pulses to move said one object to said destination position and for arresting said one object at said destination position; and means for correcting said accumulated number information prior to reaching said destination point thereby more accurately to represent the instantaneous position of said one object as it approaches said destination point, said correcting means comprising indicia means and indicia-sensing means, one fixed with respect to said one object and the other fixed with respect to said other object, said indicia-sensing means producing signals in response to sensing of said indicia, signal gating means responsive to said accumulated number information for selecting a signal from said indicia-sensing means produced by the last one of said indicia sensed prior to reaching said destination point, and means for utilizing said selected signal to correct said accumulated number information, said indicia means comprising an accurate scale member fixed to said one object and said indicia-sensing means comprising optical-photoelectric means for sensing when any of said indicia occupy a predetermined position, said computer means being responsive to said corrected accumulated number information to move said one object to said destination position after said correcting occurs.
Claim 3
Dependent Claim
56 words
Apparatus in accordance with claim 1, comprising means for providing an offset between said indicia means and said indicia-sensing means at the beginning of said displacinG of said one object, such that said signals produced by said indicia-sensing means occur for values of said displacement differing substantially from integral multiples of the distance between said indicia.
Claim 4
Dependent Claim
23 words
Apparatus in accordance with claim 2, in which said offset is substantially equal to one-half the distance between successive ones of said indicia.
Claim 5
Dependent Claim
392 words
Apparatus for automatically displacing an object by a controlled distance, from a reference position to a desired destination position, comprising: screw means responsive to rotation thereof to move said first object along said direction; pulse motor means responsive to successive driving pulses for moving said object from said reference position toward said destination position by fine increments of said distance; a source of driving pulses and means for applying them to actuate said pulse motor means; a source of command-data signals representing the required number of said fine increments to move said object by said distance, said signals representing said number in terms of a multidigit numeral; first storage means responsive to said command-data signals for storing information as to the values of higher-order digits of said numeral and second storage means responsive to said command-data signals for storing information as to the values of all digits of said numeral; means for counting said driving pulses and for providing stored information representative of the total number P of said pulses applied to said pulse motor means during said displacement: means for comparing said number P with said required number of fine increments and for arresting said displacement of said object when said number P and said required number are equal; indicia means moving with said object and comprising a series of indicia spaced from each other along the direction of said displacement of said object by a coarse increment which is an integral multiple of said fine increment, the integral number of said coarse increments in said displacement being represented by said higher-order digits; means for sensing said indicia successively as they pass through alignment with a predetermined position during said displacement of said object; means responsive to said command-data signals and to said stored information from said counting means for producing an indicia-representing pulse from said sensing means in response to a selected one of said indicia; and means responsive to said indicia-representing pulse and to said information stored in said first storage means for correcting said number P stored in said counting means to indicate substantially exactly the number of said fine increments traversed by said object up to the time of occurrence of said indicia-representing pulse, and for thereafter applying to said pulse motor means the correct number of pulses to move said object to said desired destination position.
Claim 6
Dependent Claim
392 words
Apparatus for automatically displacing an object by a controlled distance, from a reference position to a desired destination position, comprising: screw means responsive to rotation thereof to move said first object along said direction; pulse motor means responsive to successive driving pulses for moving said object from said reference position toward said destination position by fine increments of said distance; a source of driving pulses and means for applying them to actuate said pulse motor means; a source of command-data signals representing the required number of said fine increments to move said object by said distance, said signals representing said number in terms of a multidigit numeral; first storage means responsive to said command-data signals for storing information as to the values of higher-order digits of said numeral and second storage means responsive to said command-data signals for storing information as to the values of all digits of said numeral; means for counting said driving pulses and for providing stored information representative of the total number P of said pulses applied to said pulse motor means during said displacement: means for comparing said number P with said required number of fine increments and for arresting said displacement of said object when said number P and said required number are equal; indicia means moving with said object and comprising a series of indicia spaced from each other along the direction of said displacement of said object by a coarse increment which is an integral multiple of said fine increment, the integral number of said coarse increments in said displacement being represented by said higher-order digits; means for sensing said indicia successively as they pass through alignment with a predetermined position during said displacement of said object; means responsive to said command-data signals and to said stored information from said counting means for producing an indicia-representing pulse from said sensing means in response to a selected one of said indicia; and means responsive to said indicia-representing pulse and to said information stored in said first storage means for correcting said number P stored in said counting means to indicate substantially exactly the number of said fine increments traversed by said object up to the time of occurrence of said indicia-representing pulse, and for thereafter applying to said pulse motor means the correct number of pulses to move said object to said desired destination position.
Claim 7
Dependent Claim
76 words
Apparatus in accordance with claim 4, wherein said selected one of said indicia is the last of said indicia to be sensed prior to displacement by the distance indicated by said higher-order digits, and wherein said sensing means is offset from said indicia by a predetermined amount when said displacement is begun whereby said indicia-representing pulse and said correcting are produced prior to displacement of said object by the distance represented by said higher order digits.
Claim 8
Dependent Claim
48 words
Apparatus in accordance with claim 5, comprising means for reducing the rate of application of said driving pulses to said pulse motor means after said correcting, thereby to slow down said displacement of said object as it approaches said destination position and to permit more accurate arresting thereof.
Claim 9
Dependent Claim
362 words
Automatic positioning apparatus for displacing one object with respect to another object by a controlled distance, comprising: screw means responsive to rotation thereof to move said one object with respect to said other by an amount which is nominally the samE for each rotation of said screw means; pulse motor means for rotating said screw means by a predetermined angular increment in response to each driving pulse applied to said pulse motor means thereby to provide movement of said one object by a fine increment of said distance in response to each said pulse; command-data input means for supplying numerical data representing said distance; means for applying driving pulses to said pulse motor means; means for counting said driving pulses and producing signals representative of the count accumulated therein; indicia means and indicia-sensing means, one of said two last-named means being fixed with respect to said one object and the other being fixed with respect to said other object, said indicia means comprising graduations spaced-apart from each other by coarse increments large compared with said fine increments of distance, said indicia-sensing means being normally inhibited from operating but responsive to a gating signal applied thereto to become operative during a limited time interval to produce a graduation-indicating signal when one of said graduations becomes aligned with said indicia-sensing means during said time interval; means responsive to said count-representing signals and to said distance-representing numerical data to generate and apply said gating signal to said indicia-sensing means during a time embracing the expected time of alignment with said indicia-sensing means of one of the last of said indicia-means to become so aligned prior to displacement of said one object by said controlled distance, thereby to produce an indicia-representing signal accurately representative of the distance by which said one object has thus far been displaced; means for determining from said indicia-representing signal and from said numerical data the additional number of said driving pulses required to move said one object through the remaining portion of said distance; and means for thereafter applying said additional number of said pulses to said pulse motor means to complete displacement of said one object by said controlled distance.
Claim 10
Dependent Claim
362 words
Automatic positioning apparatus for displacing one object with respect to another object by a controlled distance, comprising: screw means responsive to rotation thereof to move said one object with respect to said other by an amount which is nominally the samE for each rotation of said screw means; pulse motor means for rotating said screw means by a predetermined angular increment in response to each driving pulse applied to said pulse motor means thereby to provide movement of said one object by a fine increment of said distance in response to each said pulse; command-data input means for supplying numerical data representing said distance; means for applying driving pulses to said pulse motor means; means for counting said driving pulses and producing signals representative of the count accumulated therein; indicia means and indicia-sensing means, one of said two last-named means being fixed with respect to said one object and the other being fixed with respect to said other object, said indicia means comprising graduations spaced-apart from each other by coarse increments large compared with said fine increments of distance, said indicia-sensing means being normally inhibited from operating but responsive to a gating signal applied thereto to become operative during a limited time interval to produce a graduation-indicating signal when one of said graduations becomes aligned with said indicia-sensing means during said time interval; means responsive to said count-representing signals and to said distance-representing numerical data to generate and apply said gating signal to said indicia-sensing means during a time embracing the expected time of alignment with said indicia-sensing means of one of the last of said indicia-means to become so aligned prior to displacement of said one object by said controlled distance, thereby to produce an indicia-representing signal accurately representative of the distance by which said one object has thus far been displaced; means for determining from said indicia-representing signal and from said numerical data the additional number of said driving pulses required to move said one object through the remaining portion of said distance; and means for thereafter applying said additional number of said pulses to said pulse motor means to complete displacement of said one object by said controlled distance.
Claim 11
Dependent Claim
44 words
Apparatus in accordance with claim 13, in which said correcting signal is produced in response to the last one of said indicia sensed by said sensing means prior to displacement of said one object by the distance represented by higher-order digits of said command-data.
Claim 12
Dependent Claim
24 words
Apparatus in accordance with claim 8, in which said offset is substantially equal to one-half the distance between successive indicia of said indicia means.
Claim 13
Dependent Claim
323 words
Apparatus for the automatic positioning of machine tools, measuring devices and the like by moving a first body with respect to a second body along a predetermined path and through a predetermined distance, comprising: screw means responsive to rotation thereof to move said body along said path; pulse motor means connected to said screw means for rotating said screw means by a predetermined angular amount in response to each driving pulse supplied thereto, thereby to move said first body along said path by a fine increment in response to each of said pulses; means for applying driving pulses to said pulse motor means to rotate said screw means and to move said body through said distance in said fine increments; means for controlling the number of said driving pulses to be applied to said pulse motor means in such manner as to arrest said rotation of said screw means when said first body has moved through substantially said predetermined distance; said pulse-number controlling means comprising a scale member fixed with respect to one of said bodies and having graduation spaced from each other by coarse increments large compared with said fine increments, optical-photoelectric graduation-sensing means fixed with respect to the other of said bodies for sensing said graduations to produce an electrical signal when any one of said graduations attains a predetermined position with Respect to said second body, means for normally inhibiting operation of said graduation-sensing means, means responsive to said driving pulses for enabling operating of said graduation-sensing means during an interval embracing the expected time of occurrence of that electrical signal produced by the last graduation to attain said position prior to completion of motion of said first body through said predetermined distance, means responsive to said electrical signal to correct the number of additional driving pulses to be applied to said pulse motor after said correcting, and means for applying said corrected number of pulses to said pulse motor.
Claim 14
Dependent Claim
323 words
Apparatus for the automatic positioning of machine tools, measuring devices and the like by moving a first body with respect to a second body along a predetermined path and through a predetermined distance, comprising: screw means responsive to rotation thereof to move said body along said path; pulse motor means connected to said screw means for rotating said screw means by a predetermined angular amount in response to each driving pulse supplied thereto, thereby to move said first body along said path by a fine increment in response to each of said pulses; means for applying driving pulses to said pulse motor means to rotate said screw means and to move said body through said distance in said fine increments; means for controlling the number of said driving pulses to be applied to said pulse motor means in such manner as to arrest said rotation of said screw means when said first body has moved through substantially said predetermined distance; said pulse-number controlling means comprising a scale member fixed with respect to one of said bodies and having graduation spaced from each other by coarse increments large compared with said fine increments, optical-photoelectric graduation-sensing means fixed with respect to the other of said bodies for sensing said graduations to produce an electrical signal when any one of said graduations attains a predetermined position with Respect to said second body, means for normally inhibiting operation of said graduation-sensing means, means responsive to said driving pulses for enabling operating of said graduation-sensing means during an interval embracing the expected time of occurrence of that electrical signal produced by the last graduation to attain said position prior to completion of motion of said first body through said predetermined distance, means responsive to said electrical signal to correct the number of additional driving pulses to be applied to said pulse motor after said correcting, and means for applying said corrected number of pulses to said pulse motor.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |