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US3718289A Expired / Lapsed US ⏱️ 0.0 years remaining

Reel servo system

Assignee: PERTEC PERIPHERALS Corp 9600 IRONDALE AVE CHATSWORTH CA 91311 A CORP OF
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Filing: 1971-03-05
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Granted: 1973-02-27
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Expires: 1991-03-05
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Abstract

Abstract A system useful in magnetic tape transports for controlling a reel drive motor so as to provide steady tension on the tape. Magnetic tape transports generally utilize three separate motors to respectively drive the capstan and two reels. A separate servo system is usually provided for controlling the angular speed of each of the drive motors. In the case of a reel servo system, the system controls the angular speed of a reel drive motor to maintain steady tape tension in spite of (1) rapid changes in linear tape speed; e.g., start-stop operations and (2) slowly occurring changes in reel radius. A tape reservoir is formed by a spring urged tension arm which bears against the tape between the capstan and reel. The tension arm makes rapid positional changes in response to rapid tape speed changes to isolate the reel inertia from the capstan, for example, on starting. This positional change of the tension arm provides time for the reel to come up to speed and pay tape out at the tape speed established by the capstan. The tension arm makes gradual positional changes in response to variation in radius of the tape quantity on the reel. In accordance with the invention, a first electrical signal, produced in response to tension arm position, together with a second electrical signal indicative of capstan speed, is used to control the angular speed of the reel drive motor. The major portion of the range of possible tension arm position change is dedicated to allowing for rapid changes required in reel angular speed as a consequence of changes in capstan speed and a considerably smaller portion of this range is dedicated to changing reel angular speed in response to changes in tape quantity radius.

Inventors

  • 👤 Benjamin Alaimo

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 20:11
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/18; G11B15/46; G11B15/43; G11B15/56

Claims Analysis

Total Claims: 12
Claim 1
Independent Claim 100 words
A system useful for controlling the speed of a motor coupled to a reel of a tape transport apparatus which includes a capstan for pulling tape from or supplying tape to said reel and a reservoir means between said capstan and reel for storing variable lengths of tape, said system comprising: means providing a first electrical signal indicative of the length of tape stored in said reservoir; means providing a second electrical signal related to the speed of said capstan; and circuit means responsive to said first and second electrical signals for supplying a speed controlling signal to said motor.
Claim 2
Independent Claim 100 words
A system useful for controlling the speed of a motor coupled to a reel of a tape transport apparatus which includes a capstan for pulling tape from or supplying tape to said reel and a reservoir means between said capstan and reel for storing variable lengths of tape, said system comprising: means providing a first electrical signal indicative of the length of tape stored in said reservoir; means providing a second electrical signal related to the speed of said capstan; and circuit means responsive to said first and second electrical signals for supplying a speed controlling signal to said motor.
Claim 3
Dependent Claim 60 words
The system of claim 1 wherein said reservoir means includes a tensiOn arm mounted for movement toward and away from said capstan, said tension arm resiliently bearing against said tape between said reel and said capstan to form a loop therein; and wherein said means providing a first electrical signal includes means responsive to the position of said tension arm.
Claim 4
Dependent Claim 133 words
In a tape transport apparatus including a reel and a capstan for pulling tape from or supplying tape to said reel, a servo system for controlling the speed of a drive motor coupled to said reel, said servo system comprising: a tension arm mounted for movement along a fixed path toward and away from said capstan and adapted to bear against said tape between said reel and said capstan to form a loop therein; means responsive to the position of said arm along said fixed path for producing a first electrical signal indicative thereof; means producing a second electrical signal proportional to the speed of said capstan; and amplifier means responsive to the difference between said first and second signals for developing a drive current for controlling the torque of said drive motor.
Claim 5
Dependent Claim 133 words
In a tape transport apparatus including a reel and a capstan for pulling tape from or supplying tape to said reel, a servo system for controlling the speed of a drive motor coupled to said reel, said servo system comprising: a tension arm mounted for movement along a fixed path toward and away from said capstan and adapted to bear against said tape between said reel and said capstan to form a loop therein; means responsive to the position of said arm along said fixed path for producing a first electrical signal indicative thereof; means producing a second electrical signal proportional to the speed of said capstan; and amplifier means responsive to the difference between said first and second signals for developing a drive current for controlling the torque of said drive motor.
Claim 6
Dependent Claim 26 words
The apparatus of claim 3 including spring means coupled to said tension arm acting in a direction to maximize the length of tape in said loop.
Claim 7
Dependent Claim 43 words
The apparatus of claim 4 wherein said drive current developed by said amplifier means when said capstan is at rest produces a torque in said drive motor acting oppositely to said spring means to substantially center said tension arm along said fixed path.
Claim 8
Dependent Claim 87 words
The apparatus of claim 5 wherein said first signal has a magnitude substantially proportional to the deviation of said tension arm from said center position and wherein said second signal is comprised of a ramp portion representing an interval of capstan acceleration and a level portion representing an interval of constant capstan speed and whereby deviations in said tension arm position during intervals of constant capstan speed will produce greater changes in motor drive current than corresponding deviations in tension arm position during intervals of capstan acceleration.
Claim 9
Dependent Claim 63 words
The apparatus of claim 6 wherein acceleration of said capstan from rest to said constant capstan speed produces movement of said tension arm in a direction to reduce the length of tape in said loop and wherein a decreasing radius of tape on said reel produces movement of said tension arm in a direction to reduce the length of tape in said loop.
Claim 10
Dependent Claim 15 words
The apparatus of claim 3 including means for limiting the magnitude of said drive current.
Claim 11
Dependent Claim 50 words
The system of claim 1 wherein said circuit means is responsive to a given deviation of tape length in said reservoir for producing a first change in said speed controlling signal for a constant capstan speed and a different change in said speed controlling signal for a changing capstan speed.
Claim 12
Dependent Claim 61 words
The system of claim 9 wherein said circuit means includes an amplifier having an input terminal; summing circuit means including a summing junction output terminal and first and second summing input terminals respectively connected to said means providing said first signal and said means providing said second signal; and means connecting said summing junction output terminal to said amplifier input terminal.

References Cited (Backward Citations)

US3319901A Cited
US3324320A Cited
US3318546A Cited
US3606198A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1976-02-27 1976-08-28 1977-02-27 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1980-02-27 1980-08-28 1981-02-27 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1984-02-27 1984-08-28 1985-02-27 $7700.00 Window Closed / Lapsed

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