US3876168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motor control for tape transport system
Assignee: Storage Technology Corp
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Filing: 1972-05-15
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Granted: 1975-04-08
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Expires: 1992-05-15
Abstract
Abstract A motor control circuit automatically changes the reel motor voltage constant in response to changed operating conditions. A shunt wound D.C. reel drive motor is switched from high K.sub.v, high torque, to low K.sub.v, high speed, when the magnetic tape reaches a predetermined position. Tape loop position sensing switches in the slack tape vacuum column control the position of the tape loop at an upper position when the tape is being driven in one direction and at a lower position when the tape is being driven in the other position. When the tape loop goes above the upper position, or below the lower position, a switch decreases the field current to achieve a low K.sub.v. When the reel motor armature supply voltage drops below a certain level, an additional resistance is switched in parallel with the normal armature limiting resistance. This provides increased armature current to maintain the motor response time at an acceptable level even though the armature supply voltage has fallen.
Inventors
- 👤 Jr Gale A Powers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:05
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/56; G11B15/58; H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/298
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
162 words
A magnetic tape transport system comprising: a file reel and a machine reel; a drive motor for said file reel and a drive motor for said machine reel, a magnetic head mounted intermediate said reels, a capstan means for driving said tape past said head and between said reels, a pair of slack tape vacuum columns each having an open end disposed adjacent each of said reels on opposite sides of said head, and each having a closed end, tape loop position sensing switches associated with each of said slack vacuum columns, for producing a switching signal in response to the approach by said tape to a predetermined distance from either said open or said closed end of each of said columns, a control system for each reel drive motor, means in said control system responsive to said switching signal for switching the field of a drive motor between a high torque motor voltage contant to a high speed motor voltage constant.
Claim 2
Dependent Claim
162 words
A magnetic tape transport system comprising: a file reel and a machine reel; a drive motor for said file reel and a drive motor for said machine reel, a magnetic head mounted intermediate said reels, a capstan means for driving said tape past said head and between said reels, a pair of slack tape vacuum columns each having an open end disposed adjacent each of said reels on opposite sides of said head, and each having a closed end, tape loop position sensing switches associated with each of said slack vacuum columns, for producing a switching signal in response to the approach by said tape to a predetermined distance from either said open or said closed end of each of said columns, a control system for each reel drive motor, means in said control system responsive to said switching signal for switching the field of a drive motor between a high torque motor voltage contant to a high speed motor voltage constant.
Claim 3
Dependent Claim
42 words
The magnetic tape transport system recited in claim 1 wherein said drive motor has a field winding and wherein said means for switching comprises: an electronic switch connected to said field winding for changing the rated field current of said drive motor.
Claim 4
Dependent Claim
149 words
The tape transport system recited in claim 1 further comprising: tape loop position sensing switches spaced longitudinally of each column and actuated as the tape loop passes over each switch, said tape loop position sensing switches being connected to said control system to maintain said tape loop in an upper drive zone when said motor is driving tape in one direction, and in a lower drive zone when said drive motor is driving tape in the other direction, an upper tape loop position sensing switch at an upper predetermined point in said upper drive zone, a lower tape loop position sensing switch at a lower predetermined point in said lower drive zone, said upper and lower tape loop position sensing switches being connected to said switching means to decrease said motor voltage constant when said tape loop is above said upper predetermined point or below said lower predetermined point.
Claim 5
Dependent Claim
62 words
The tape transport system recited in claim 3 wherein said motor has a field winding, wherein said switching means is connected to said field winding and wherein said upper and lower tape loop position sensing switches are connected to decrease the current through said field winding when said tape loop is above said upper predetermined point or below said lower predetermined point.
Claim 6
Dependent Claim
89 words
The tape transport recited in claim 4 wherein said switching means comprises: an electronic switching device in parallel with an external resistor both of which are in series with the field of said drive motor, said upper tape loop position sensing switch being connected to turn said solid state switching device off when said tape loop is above said upper predetermined position, said lower tape loop position sensing switch being connected to turn said solid state switching device off when said tape loop is below said lower predetermined position.
Claim 7
Dependent Claim
85 words
A magnetic tape transport system comprising: a file reel and a machine reel, a drive motor for said file reel and a drive motor for said machine reel, a magnetic head mounted intermediate said reels, capstan means for driving said tape past said head and between said reels, means for sensing said reel motor supply voltage, and means responsive to said sensing means and connected to the motor armature for increasing the armature current when said reel motor supply voltage drops below a given value.
Claim 8
Dependent Claim
85 words
A magnetic tape transport system comprising: a file reel and a machine reel, a drive motor for said file reel and a drive motor for said machine reel, a magnetic head mounted intermediate said reels, capstan means for driving said tape past said head and between said reels, means for sensing said reel motor supply voltage, and means responsive to said sensing means and connected to the motor armature for increasing the armature current when said reel motor supply voltage drops below a given value.
Claim 9
Dependent Claim
71 words
The tape transport system recited in claim 6 wherein said means connected to the motor armature comprises: a limiting resistance in series with said drive motor armature, and a voltage controlled switch in parallel with said limiting resistance, said sensing means being connected to close said switch when said armature voltage drops below a given value thereby decreasing the resistance in series with said armature and increasing said motor armature current.
Claim 10
Dependent Claim
46 words
The tape transport recited in claim 7 wherein said voltage controlled switch includes an electronic switching device, said reel motor armature voltage being applied to said electronic switching device to turn said switching device on when said reel motor armature voltage drops below a predetermined level.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |