Patent US2970041A successfully refreshed from Google Patents.
Patent US3839664A successfully refreshed from Google Patents.
US3839664A
Expired / Lapsed
US
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Magnetic disc head linear motor positioning system
Assignee: Dirks Electronics Corp
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Filing: 1972-02-10
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Granted: 1974-10-01
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Expires: 1992-02-10
Abstract
Abstract A high precision linear positioning system for the positioning of signal heads in magnetic disc data storage systems or the like employing an actuator having an axially movable magnet rod mechanically linked to the head and a pair of fixed electromagnet coils respectively disposed about the ends of the magnet rod. The coils are suitably energized by an electronic control circuit to impart motive force to the magnet rod. The actuator includes a phototransducer assembly adapted to produce binary coded electrical signals corresponding to the specific track address at which the head is instantly located. The electronic control circuit is adapted for two modes of operation. In the first mode, the electronic control circuit functions to continuously subtract the desired binary track address entered into the system from the instant binary track address produced by the phototransducer assembly, and to velocity servo the actuator in response thereto. In the second mode of operation, employed after the head has reached the desired track, suitable switching circuitry interconnects the electronic control circuit in a position servo mode, employing as input, signals from additional photosensors in the phototransducer assembly, disposed in quadrature, to precisely position and detent the head above the desired track.
Inventors
- 👤 G Dirks
- 👤 G Scott
- 👤 W Dirks
- 👤 D Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:35
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/58; G11B5/596; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/19; G05B19/27; G05B19/29; G05B19/291; G05B19/293; G11B5/54; G11B5/55; G11B5/5521; G05B2219/00; G05B2219/30; G05B2219/43; G05B2219/43179
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
119 words
An actuator for translating an element along a linear path comprising an elongate permanent magnet rod slideably mounted for axial movement, linkage means mechanically interconnecting said element and said magnet rod, a pair of electromagnet coils respectively disposed about the ends of said magnet rod, energizing means for energizing both of said coils to impart both attractive and repulsive axial force to said magnet rod and limiting means for limiting the current to the one coil imparting repulsive force to said magnet rod so that the magnetic field of said one coil at said magnet rod is smaller than the field corresponding to the knee on the hysteresis curve of said magnet rod, minimizing demagnetization of said magnet rod.
Claim 2
Dependent Claim
119 words
An actuator for translating an element along a linear path comprising an elongate permanent magnet rod slideably mounted for axial movement, linkage means mechanically interconnecting said element and said magnet rod, a pair of electromagnet coils respectively disposed about the ends of said magnet rod, energizing means for energizing both of said coils to impart both attractive and repulsive axial force to said magnet rod and limiting means for limiting the current to the one coil imparting repulsive force to said magnet rod so that the magnetic field of said one coil at said magnet rod is smaller than the field corresponding to the knee on the hysteresis curve of said magnet rod, minimizing demagnetization of said magnet rod.
Claim 3
Dependent Claim
34 words
Apparatus according to claim 1 comprising phototransducer means for producing electrical signals representative of the linear position of said transducing element along said linear path, said energizing means being responsive to said electrical signals.
Claim 4
Dependent Claim
48 words
Apparatus according to claim 2 wherein said phototransducer means comprises an optical mask having binary addrss information coded thereon, photosensor means responsive to the information on said optical mask and means for translating said optical mask relative said photosensor means in response to movement of said transducing element.
Claim 5
Dependent Claim
123 words
An actuator for translating a signal head radially with respect to a magnetic disc comprising an elongate permanent magnet rod slideably mounted for axial movement, linkage means mechanically interconnecting said head and said magnet rod, a pair of electromagnet coils respectively disposed about the ends of said magnet rod and energizing means for energizing both of said coils to impart both attractive and repulsive azial force to said magnet rod including limiting means for limiting the current to the one coil imparting repulsive force to said magnet so that the magnetic field of said one coil at said magnet rod is smaLler than the field corresponding to the knee on the hysteresis curve of said magnet rod, minimizing demagnetization of said magnet rod.
Claim 6
Dependent Claim
123 words
An actuator for translating a signal head radially with respect to a magnetic disc comprising an elongate permanent magnet rod slideably mounted for axial movement, linkage means mechanically interconnecting said head and said magnet rod, a pair of electromagnet coils respectively disposed about the ends of said magnet rod and energizing means for energizing both of said coils to impart both attractive and repulsive azial force to said magnet rod including limiting means for limiting the current to the one coil imparting repulsive force to said magnet so that the magnetic field of said one coil at said magnet rod is smaLler than the field corresponding to the knee on the hysteresis curve of said magnet rod, minimizing demagnetization of said magnet rod.
Claim 7
Dependent Claim
21 words
Apparatus according to claim 4 wherein said at least one coil is energized to impart attractive force to said magnet rod.
Claim 8
Dependent Claim
129 words
An actuator for translating an element along a linear path comprising an elongate magnet rod slideably mounted for axial movement, linkage means mechanically interconnecting said element and said magnet rod, a pair of electromagnet coils respectively disposed about the ends of said magnet rod, a servo amplifier, a apir of diodes respectively connected in series with said coils and the output of said servo amplifier, the polarity of one of said diodes being opposite from the polarity of the other of said diodes and a pair of resistors respectively connected in parallel with said diodes, said resistors having values suitable to limit the current therethrough to a level corresponding to a repulsive magnetic field at said magnet rod below the knee on the hysteresis curve of said magnet rod.
Claim 9
Dependent Claim
129 words
An actuator for translating an element along a linear path comprising an elongate magnet rod slideably mounted for axial movement, linkage means mechanically interconnecting said element and said magnet rod, a pair of electromagnet coils respectively disposed about the ends of said magnet rod, a servo amplifier, a apir of diodes respectively connected in series with said coils and the output of said servo amplifier, the polarity of one of said diodes being opposite from the polarity of the other of said diodes and a pair of resistors respectively connected in parallel with said diodes, said resistors having values suitable to limit the current therethrough to a level corresponding to a repulsive magnetic field at said magnet rod below the knee on the hysteresis curve of said magnet rod.
Claim 10
Dependent Claim
56 words
Apparatus according to claim 4 wherein said linkage means comprises a shaft slideably mounted for axial movement and disposed radially with respect to said disc, said shaft carrying said signal head at one end, said shaft being in parallel spaced apart relation with said magnet rod and a yoke interconnecting said shaft and said magnet rod.
Claim 11
Dependent Claim
34 words
Apparatus according to claim 4 comprising phototransducer means for producing electrical signals representative of the radial position of said head with respect to said disc, said energizing means being responsive to said electrical signals.
Claim 12
Dependent Claim
48 words
Apparatus according to claim 8 wherein said phototransducer means comprises an optical mask having digital track address information coded thereon, photosensor means responsive to the information on said optical mask and means for translating said optical mask relative said photosensor means in response to movement of said head.
Claim 13
Dependent Claim
42 words
Apparatus according to claim 9 wherein said digital track address information on said optical mask comprises parallel rows of binary information in the form of transparent and opaque areas, said photosensor means being adapted to respond to a column of said information.
Claim 14
Dependent Claim
63 words
Apparatus according to claim 10 wherein said photosensor means comprises a plurality of photosensors disposed in column alignment with respect to said rows, one of said photosensors being aligned with each of said rows, and a plurality of light sources disposed in registration with said photosensors on the opposite side of said optical mask therefrom to illuminate said photosensors through said optical mask.
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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) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |