US3842326A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Velocity control system for reel-to-reel web drive
Assignee: Unisys Corp
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Filing: 1973-07-27
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Granted: 1974-10-15
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Expires: 1993-07-27
Abstract
Abstract In a reel-to-reel drive wherein a web member is moved from a supply reel to a take-up reel by electrically driving the take-up reel, the velocity of the web is maintained constant, as the supply reel is loaded with the web member, by decreasing the rotational velocity of the take-up reel in proportion to the loading of the web member on the take-up reel. The speed of the moving web is derived digitally, the digital signals being compared in time of occurrence, for a predetermined sample length with a reference clock source. The time difference of occurrence between the actual digital web signal and the desired web speed or reference clock signal causes a voltage correction to be generated that is proportional in amplitude to the present takeup reel motor drive voltage and equal in duration to the time difference of occurrence between the actual digital web speed signal and the desired web speed signal. In instances where the web member is a magnetic tape with magnetically encoded digital data thereon in record lengths that are shorter than the predetermined sample length and having inter-record gaps, an approximate voltage correction is generated in proportion to the time difference of occurrence between the actual web speed signal and a reference signal, on a bit-to-bit basis. If the digital web speed indication is derived from a clock track on the magnetic tape, the occurrence of inter-record gaps, exhibiting the absence of clock information, will cause the generation of a driving voltage for the reel motor that will maintain, at least for the length of the inter-record gap, takeup reel velocity at the level existing at the time the interrecord gap occurred.
Inventors
- 👤 H Stocker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:29
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/18; G11B15/46; G11B15/52
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
165 words
A web velocity control system for a reel-to-reel web drive, having an electric motor for driving the take-up reel of a takeup reel, supply reel pair, comprising: means for generating signals indicative of the time errors between the occurrences of an actual web velocity signal and a desired web velocity signal; means, responsive to said time error indicating signal generating means, for generating web velocity correction signals that are proportional, in amplitude, to the voltage being supplied to drive the take-up reel motor and equal, in duration, to the time errors indicated by the time error indicating signals; means, responsive to the voltage being supplied to drive the take-up reel motor, for dynamically storing its instantaneous value; and means for combining the web velocity correction signals, from said web velocity correction signals generating means, and the instantaneous value of the voltage being supplied to drive the take-up reel motor, from said dynamically storing means, the combined voltage being supplied to drive the take-up reel motor.
Claim 2
Dependent Claim
165 words
A web velocity control system for a reel-to-reel web drive, having an electric motor for driving the take-up reel of a takeup reel, supply reel pair, comprising: means for generating signals indicative of the time errors between the occurrences of an actual web velocity signal and a desired web velocity signal; means, responsive to said time error indicating signal generating means, for generating web velocity correction signals that are proportional, in amplitude, to the voltage being supplied to drive the take-up reel motor and equal, in duration, to the time errors indicated by the time error indicating signals; means, responsive to the voltage being supplied to drive the take-up reel motor, for dynamically storing its instantaneous value; and means for combining the web velocity correction signals, from said web velocity correction signals generating means, and the instantaneous value of the voltage being supplied to drive the take-up reel motor, from said dynamically storing means, the combined voltage being supplied to drive the take-up reel motor.
Claim 3
Dependent Claim
132 words
The web velocity control system of claim 1 wherein said time error signals generating means, comprises: first latch means for receiving binary signals at a frequency indicative of the actual velocity of the web member and generating binary signals in response thereto; second latch means for receiving binary signals at a frequency indicative of the desired velocity of the web member and generating binary signals in response thereto; and logic circuit means, responsive to the binary signals from said first and second latch means, for generating a first binary output when the actual web velocity indication signals are being received prior to the desired web velocity indication signals and generating a second binary signal when the desired web velocity indication signals are being received prior to the actual web velocity indication signals.
Claim 4
Dependent Claim
81 words
The web velocity control system of claim 2 wherein said web velocity correction signals generating means, comprises: a first gate meaNs responsive to the first binary output from said logic circuit means for closing in response thereto; a second gate means responsive to the second binary output from said logic circuit means for closing in response thereto; and a differential, dual input, amplifier having an inverting input and a non-inverting input, said first gate means being connected to the non-inverting input.
Claim 5
Dependent Claim
97 words
The web velocity control system of claim 1 wherein said web velocity correction signals generating means, comprises: first gate means responsive to said time error indicating signal generating means for closing in response thereto; second gate means responsive to said time error indicating signal generating means for closing in response thereto; and a differential, dual input, amplifier having an inverting input and a non-inverting input, said first gate means being connected to the inverting input and said second gate means being connected to the non-inverting input, the output of said amplifier being the web velocity correction signals.
Claim 6
Dependent Claim
31 words
The web velocity control system of claim 4 wherein said combining means comprises: a two input summing amplifier, the first input being the web velocity correction signals from said differential amplifier.
Claim 7
Dependent Claim
40 words
The web velocity control system of claim 5 wherein the output voltage of said summing amplifier is supplied to said electric motor to drive it, and is also supplied to both the inverting and non-inverting inputs of said differential amplifier.
Claim 8
Dependent Claim
111 words
The web velocity control system of claim 1 further comprising a second time error signals generating means, said second signals generating means comprising: a one-shot multivibrator circuit having a time-out constant that equals the time displacement between binary signals that indicate the desired web velocity, said multivibrator being set each time a binary signal that indicates actual web velocity occurs; logic circuit means, responsive to the output from said multivibrator, for generating a first binary output when said multivibrator is set again before it timesout and generating a second binary output when the multivibrator times-out before it is set again; and means for disabling said second time error signal generating means.
Claim 9
Dependent Claim
69 words
The web velocity control system of claim 7 wherein said web velocity correction signals generating means, comprises: a capacitor having an initial charge thereon; first gate means, responsive to the first binary output from said logic circuit means, for closing a discharge path for said capacitor; and second gate means, responsive to the second binary output from said logic circuit means, for closing a charge path for said capacitor.
Claim 10
Dependent Claim
52 words
The web velocity control system of claim 1, wherein said combining means comprises a two input summing amplifier, the first input being the web velocity correction signals; and wherein said dynamically storing means comprises a capacitor having an initial positive voltage charge thereon connected to the second input of said summing amplifier.
Claim 11
Dependent Claim
27 words
The web velocity control system of claim 9 further comprising: isolation means for connecting the output of said summing amplifier to the positive side of said capacitor.
Claim 12
Dependent Claim
198 words
In a magnetic tape drive having a pre-recorded clock track on the magnetic tape and an electric motor for driving a take-up reel, a tape velocity control system, comprising: first means for generating signals indicative of the time errors between the occurrences of binary clock signals read from the pre-recorded clock track representing actual tape velocity and binary signals representing the desired time displacement between the read clock signals; means responsive to a binary signal indicating existence of a record longer than a predetermined length for inhibiting said first time error signals generating means; second means for generating signals indicative of the time errors between the occurrenCes of binary signals representing actual tape velocity, that are occurring at a rate obtained by dividing the binary clock signal rate by a factor greater than one, and binary signals representing the desired time displacement between the binary signals representing actual tape velocity; and means, responsive to said second time error signals generating means for generating tape velocity correction signals that are proportional, in amplitude, to the voltage presently supplied to drive the take-up reel motor and equal, in duration, to the time errors indicated by the time error indicating signals.
Claim 13
Dependent Claim
198 words
In a magnetic tape drive having a pre-recorded clock track on the magnetic tape and an electric motor for driving a take-up reel, a tape velocity control system, comprising: first means for generating signals indicative of the time errors between the occurrences of binary clock signals read from the pre-recorded clock track representing actual tape velocity and binary signals representing the desired time displacement between the read clock signals; means responsive to a binary signal indicating existence of a record longer than a predetermined length for inhibiting said first time error signals generating means; second means for generating signals indicative of the time errors between the occurrenCes of binary signals representing actual tape velocity, that are occurring at a rate obtained by dividing the binary clock signal rate by a factor greater than one, and binary signals representing the desired time displacement between the binary signals representing actual tape velocity; and means, responsive to said second time error signals generating means for generating tape velocity correction signals that are proportional, in amplitude, to the voltage presently supplied to drive the take-up reel motor and equal, in duration, to the time errors indicated by the time error indicating signals.
Claim 14
Dependent Claim
92 words
The tape velocity control system of claim 11 wherein said first time error signals generating means, comprises: a one-shot multivibrator circuit having a time-out constant that equals the time displacement desired between the binary clock signals read from the tape, said multivibrator being set each time a clock signal is read; and logic circuit means, responsive to the output from said multivibrator for generating a first binary output when said multivibrator is set again before it times-out and generating a second binary output when the multivibrator times-out before it is set again.
Claim 15
Dependent Claim
130 words
The tape velocity control system of claim 11 wherein said second time error signals generating means, comprises: first latch means for receiving the binary signals representing actual tape velocity and generating binary signals in response thereto; second latch means for receiving the binary signals representing the desired time displacement between the binary signals representing actual tape velocity and generating binary signals in response thereto; and logic circuit means, responsive to the binary signals from said first and second latch means, for generating a first binary output when the actual tape velocity indicating binary signals are being received prior to the desired time displacement indicating signals, and generating a second binary signal when the desired time displacement indicating signals are being received prior to the actual tape velocity indicating binary signals.
Claim 16
Dependent Claim
92 words
The tape velocity control system of claim 11 wherein said tape velocity correction signals generating means, comprises: first gate means, responsive to said second time error indicating signal generating means for closing in response thereto; second gate means, responsive to said second time error indicating signal generating means, for closing in response thereto; and a differential, dual input, amplifier having an inverting input and a non-inverting input, said first gate means being connected between the inverting input and ground, and said second gate means being connected between the non-inverting input and ground.
Claim 17
Dependent Claim
88 words
The tape velocity control system of claim 14 further comprising: a two input summing amplifier, the first input being connected to the output of said differential amplifier; a capacitor connected between the second input of said summing amplifier and ground; a bidirectional isolation means for connecting the output of said summing amplifier to the second input of said summing amplifier and the positive side of said capacitor; and means for connecting the output of said summing amplifier to both the inverting and non-inverting inputs of said differential amplifier.
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) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |