US Patent: 3,490,017
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| Numerical Control Systems Employing Conversion of Changing Command Numbers Into Phase Analog Signals
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Patentees:
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| Norbert C. Kolell (exact or similar names) - Empire, Fond du Lac County, WI |
| Thomas B. Bullock (exact or similar names) - Fond Du Lac, Fond Du Lac County, WI |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Dec. 19, 1966 |
| Granted: |
Jan. 13, 1970 |
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Joel Havens
"Vintage Machinery" entry for Giddings & Lewis Manufacturing Co.
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Description: |
| Abstract:
A numerical control system wherein a phase-variable analog signal is created and utilized by a servo drive to control the displacement and velocity of a movable element in accordance with the extent of change and average rate of change of a periodically updated, digitally signaled command number, as disclosed in co-pending application Ser. No. 555,048; and characterized by an improvement for eliminating "misses" in the phase-variable signal which may result from "leapfrogging" under certain circumstances. A command number in a storage register is periodically updated. It is compared with a reference number signaled by a continuously running counter and which cycles between two values in phase agreement with a reference wave. At the instants during each cycle when the command number and reference number are equal, a compare pulse is created which by its phase, relative to the reference wave, corresponds to the command number. But in those cases where updating of the command number makes it "leapfrog" to a value already traversed by the reference number in a given cycle of the latter, and so that no equal comparison can occur during that cycle, the improved apparatus senses this and generates a substitute pulse closely timed to that which the "missed" pulse would have had, so that the compare pulses plus the substitute pulses form a phase-variable signal without discontinuities and thus provide smoother and more precise operation of the servo drive. |
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