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EP0024969A1
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Measuring machine and method of producing displacement-indicative signals in such a machine
Assignee: Bendix Corp
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Filing: 1980-08-01
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Granted: —
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Expires: 2000-08-01
Abstract
Abstract easuring machine and method of producing displacement-indicative pulses in such a machine in which a measuring increment is divided into smaller units for better resolution and accuracy; the increased measurement resolution is accomplished by detecting a Moire fringe pattern at two locations, generating at least two square waves representative of the measurement, assigning a digital value to the square waves at two different times, and using the digital values of the square waves at the two times as a ROM address for look-up; the ROM has values (markers) stored as an indication of whetherthe measurement should be incremented and by how much (+1 or-1 in one embodiment); and the square waves are pulse patterns which are offset (i.e., change state at different points), using the digital values from a present state and previous state to provide a ROM address representative of whether a pulse should be created indicating a relative movement and if so providing an indication of which direction in which the apparatus is moving.
Inventors
- 👤 Gerald Lawrence Tumbush
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 13:22
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36; G01D5/12; G01D5/244; G01D5/24409; G01P; G01P13/00; G01P13/02; G01P13/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
112 words
A method of producing displacement-indicative signals in a measuring machine having a movable probe, characterized in that it comprises the steps of storing in a memory a table including input addresses and output displacement indicative of the stored values corresponding to each input address, sensing position of the probe at a first time and a second time and generating a binary code indicative of the position at each time; combining the binary codes indicative of the position at the first and second times into a digital address; and using the digital address as an input address to the memory and reading the stored value corresponding to the digital address as displacement-indicative signal.
Claim 2
Independent Claim
112 words
A method of producing displacement-indicative signals in a measuring machine having a movable probe, characterized in that it comprises the steps of storing in a memory a table including input addresses and output displacement indicative of the stored values corresponding to each input address, sensing position of the probe at a first time and a second time and generating a binary code indicative of the position at each time; combining the binary codes indicative of the position at the first and second times into a digital address; and using the digital address as an input address to the memory and reading the stored value corresponding to the digital address as displacement-indicative signal.
Claim 3
Dependent Claim
193 words
A measuring machine comprising: a base including a fixed grating (110); a movable member (120) coupled to a movable grating (122) positioned adjacent to the fixed grating (110); at least first and second photodetectors (124,126), each positioned adjacent to the gratings (110,122) for sensing relative movement of the gratings (110,122) and each producing a signal indicative of a displacement of a predetermined magnitude of said movable grating (122); characterized in that there is provided means (410,420,430) adapted to divide said predetermined magnitude into smaller regions and to produce signals for counting such regions, said means comprising: a memory (430) including a stored value at each of a plurality of digital addresses; a logic (410,420) coupled to the first and second photodetectors (124,126) and to the memory (430) for generating a binary word based upon present and past conditions of the first and second photodetectors (124,126); and means (up and down lines) coupled to the memory (430) for obtaining a signal based upon a stored value in the memory (430) at an address corresponding to the binary word generated by the logic (410,420), said signal being indicative of movement through a predetermined smaller region.
Claim 4
Dependent Claim
193 words
A measuring machine comprising: a base including a fixed grating (110); a movable member (120) coupled to a movable grating (122) positioned adjacent to the fixed grating (110); at least first and second photodetectors (124,126), each positioned adjacent to the gratings (110,122) for sensing relative movement of the gratings (110,122) and each producing a signal indicative of a displacement of a predetermined magnitude of said movable grating (122); characterized in that there is provided means (410,420,430) adapted to divide said predetermined magnitude into smaller regions and to produce signals for counting such regions, said means comprising: a memory (430) including a stored value at each of a plurality of digital addresses; a logic (410,420) coupled to the first and second photodetectors (124,126) and to the memory (430) for generating a binary word based upon present and past conditions of the first and second photodetectors (124,126); and means (up and down lines) coupled to the memory (430) for obtaining a signal based upon a stored value in the memory (430) at an address corresponding to the binary word generated by the logic (410,420), said signal being indicative of movement through a predetermined smaller region.
Claim 5
Dependent Claim
38 words
A measuring machine as claimed in claim 2, characterized in that the logic(410,420)includes devices (410, 420) for generating an address signal based.upon the present state of the photodetectors (124,126) and' an immediately preceding state of said photodetectors (124,126).
Claim 6
Dependent Claim
35 words
A measuring machine as claimed in claim 3, characterized in that said devices (410,420) includes D type flip-flops (410,420) having stored values of the present and immediate past output values of the photodetectors (124, 126).
Claim 7
Dependent Claim
42 words
A measuring machine as claimed in claim 2, characterized in that the first and second photodetectors (124, 126) are spaced from each other by a distance equal to an integral number of repeating measurement patterns plus one quarter of a measurement pattern.
Claim 8
Dependent Claim
49 words
A measuring machine as claimed in claim 2, characterized in that the stored values at each address comprise first and second binary bits, with the first bit indicative of a measurement count in the positive direction and the second bit indicative of a measurement count in the negative direction.
References Cited (Backward Citations)
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