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US3938757A
Expired / Lapsed
US
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Tape transport system including a logical network for producing quadrature pulse trains and motor control utilizing same
Assignee: Unisys Corp
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Filing: 1974-03-29
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Granted: 1976-02-17
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Expires: 1994-03-29
Abstract
Abstract A constant speed reel-to-reel tape transport system is described including a drive motor having a pair of quadrature windings, and a motor supply producing a pair of square-wave motor-drive pulse trains of the same repetition rate, but 90° out of phase, one train being supplied to each of the quadrature windings. The system further includes control means responsive to the change in the effective radius of one of the reels, for example the drive reel, for varying the repetition rate of the pulse trains, and thereby the speed of the motor, to maintain a constant linear tape speed.
Inventors
- 👤 John E. Sargunar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:03
CPC Classifications
G; G11; G11B; G11B27/00; G11B27/10; G11B27/11; G11B27/13; G11B15/00; G11B15/18; G11B15/46; G11B27/34
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
120 words
A constant speed reel-to-reel tape transport system, comprising: a tape drive reel; a tape supply reel; a drive motor driving the drive reel; said drive motor including a pair of quadrature windings; motor supply means producing a pair of square-wave motor-drive pulse trains of the same repetition rate, but 90° out of phase, and supplying one train to each of the quadrature windings of the drive motor to control its speed in accordance with the repetition rate of the pulse trains; and control means responsive to the change in the effective radius of one of said reels for varying the repetition rate of said pulse trains, and thereby the speed of the motor, to maintain a constant linear tape speed.
Claim 2
Dependent Claim
120 words
A constant speed reel-to-reel tape transport system, comprising: a tape drive reel; a tape supply reel; a drive motor driving the drive reel; said drive motor including a pair of quadrature windings; motor supply means producing a pair of square-wave motor-drive pulse trains of the same repetition rate, but 90° out of phase, and supplying one train to each of the quadrature windings of the drive motor to control its speed in accordance with the repetition rate of the pulse trains; and control means responsive to the change in the effective radius of one of said reels for varying the repetition rate of said pulse trains, and thereby the speed of the motor, to maintain a constant linear tape speed.
Claim 3
Dependent Claim
45 words
A system according to claim 1, wherein said control means is responsive to the change in the effective radius of the drive reel for varying the repetition rate of the pulse trains in inverse proportion to the change in effective radius of the drive reel.
Claim 4
Dependent Claim
69 words
A system according to claim 2, wherein said control means comprises a digital counter counting the number of pulses supplied to the drive motor and producing thereby a digital count corresponding to the number of revolutions of the drive reel, a digital-to-analogue converter producing an analogue signal corresponding to said digital count, and means varying the repetition rate of the pulse trains in inverse proportion to said analogue signal.
Claim 5
Dependent Claim
57 words
A system according to claim 3, wherein said last-named means comprises an external oscillator, a monostable oscillator driven thereby, means applying said analogue signal to said monostable oscillator to obtain an output therefrom inversely proportional to said digital count, a voltage-controlled-oscillator, and means controlling the frequency of said voltage controlled-oscillator in accordance with said last named signal.
Claim 6
Dependent Claim
65 words
A system according to claim 1, wherein said motor supply means comprises; means producing a first pulse train of a repetition rate and pulse width in accordance with the desired speed of the motor, and circuit means producing from said first pulse train said pair of motor-drive pulse trains each having one-half the repetition rate and double the pulse width of said first pulse train.
Claim 7
Dependent Claim
129 words
A system according to claim 5, wherein said circuit means comprise: a triggering flip-flop connected to receive at its input said first pulse train and to produce said second pulse train at one of its outputs; a first NAND-gate having a pair of inputs and an output; an OR-gate having a pair of inputs and an output; means supplying said first pulse train and said second pulse train to the pair of inputs of said first NAND-gate and to the pair of inputs of said OR-gate; a second NAND-gate having a pair of inputs and an output; and means supplying the outputs of said first NAND-gate and said OR-gate to the pair of inputs of said second NAND-gate to produce said third train of pulses at the output thereof.
Claim 8
Dependent Claim
15 words
A system according to claim 1, wherein said drive motor is a hysteresis synchronous motor.
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) | 1979-02-16 | 1979-08-18 | 1980-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-16 | 1983-08-18 | 1984-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-16 | 1987-08-18 | 1988-02-17 | $7700.00 | Window Closed / Lapsed |