US3701992A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Servosystem for graphical recorder
Assignee: HP Inc
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Filing: 1971-11-01
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Granted: 1972-10-31
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Expires: 1991-11-01
Abstract
Abstract An X-Y graphical recorder has a moving pen which is moved along each axis by a position feedback servosystem responsive to digital data from a vector generator. The servosystem includes two parallel connected operational amplifiers, one of which provides an output proportional to analog pen position control signals and the other of which produces a constant level output in response to any pen position control signal greater than the predetermined low value. The outputs from the two servoamplifiers are summed and coupled to a servomotor which drives the pen.
Inventors
- 👤 Daniel E Allen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:04
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/22
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
135 words
In an X-Y plotter including a positionable writing stylus; a servomotor for moving said stylus; servoamplifier means having an input for receiving an analog stylus control signal from an external source and for driving said servomotor in response to said control signals; and means responsive to the position of said writing stylus for providing a position feedback signal to the input of said servoamplifier means, the improvement wherein said servoamplifier means comprises: first amplifier means for providing a first output signal proportional to the signal at said input; second amplifier means coupled in parallel with said first amplifier means and operative in response to a predetermined signal level at said input for providing a second constant level output signal having a predetermined magnitude selected to drive said servomotor to overcome frictional forces in said servomotor.
Claim 2
Dependent Claim
135 words
In an X-Y plotter including a positionable writing stylus; a servomotor for moving said stylus; servoamplifier means having an input for receiving an analog stylus control signal from an external source and for driving said servomotor in response to said control signals; and means responsive to the position of said writing stylus for providing a position feedback signal to the input of said servoamplifier means, the improvement wherein said servoamplifier means comprises: first amplifier means for providing a first output signal proportional to the signal at said input; second amplifier means coupled in parallel with said first amplifier means and operative in response to a predetermined signal level at said input for providing a second constant level output signal having a predetermined magnitude selected to drive said servomotor to overcome frictional forces in said servomotor.
Claim 3
Dependent Claim
43 words
The apparatus of claim 1, wherein said second amplifier means includes an operational amplifier having input and output terminals and a pair of oppositely poled asymmetrically conducting elements coupled in series in a feedback loop between said last named output and input terminals.
Claim 4
Dependent Claim
13 words
The apparatus of claim 2, wherein said asymmetrically conducting elements are Zener diodes.
Claim 5
Dependent Claim
27 words
The apparatus of claim 2, further including means coupled to the output of said second amplifier means for adjusting the magnitude of said constant level output signal.
Claim 6
Dependent Claim
35 words
The apparatus of claim 1, further including means coupled to said first and second amplifier means for summing said first and second output signals therefrom, said summing means having an output coupled to said servomotor.
Claim 7
Dependent Claim
13 words
The apparatus of claim 5, wherein said summing means includes an operational amplifier.
Claim 8
Dependent Claim
28 words
The apparatus of claim 1, wherein said servoamplifier means further includes operational amplifier means for coupling the signals at said input to said first and second amplifier means.
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) | 1975-10-31 | 1976-05-01 | 1976-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-31 | 1980-05-01 | 1980-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-31 | 1984-05-01 | 1984-10-31 | $7700.00 | Window Closed / Lapsed |