US4462053A
Expired / Lapsed
US
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Method for controlling a disc head
Assignee: SAMUEL N IRWIN 3 REGENT CT ANN ARBOR MI 48104
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Filing: 1981-07-02
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Granted: 1984-07-24
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Expires: 2001-07-02
Abstract
Abstract A method for positioning and maintaining a disc head over a desired track centerline on a disc rotatably carried on a disc drive. The distance between the current position of the disc head and the desired track centerline is monitored, and a signal generally proportional to that distance is applied to the disc head moving mechanism to cause the disc head to move toward the track centerline. The control signal is clipped if it exceeds predetermined maximum and minimum values.
Inventors
- 👤 Francis Lum
- 👤 Bruce Graham
- 👤 Samuel N. Irwin
- 👤 Juan F. Velazquez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:10
CPC Classifications
G; G11; G11B; G11B21/00; G11B21/02; G11B21/08; G11B21/081; G11B21/083; G11B21/085; G11B5/00; G11B5/48; G11B5/58; G11B5/596; G11B5/59605; G11B5/59622
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
210 words
A method for positioning and maintaining a disc head over a desired track centerline on a disc, said disc having a plurality of tracks and embedded servo information associated with each of said tracks, including track identification, said disc rotatably carried on a disc drive having means for moving said disc head, said method comprising the steps of: waiting for a portion of said embedded servo information to pass under said disc head; reading said portion of said embedded servo information; determining the current position of said disc head with an uncertainty of no greater than one-half track width; calculating the minimum possible distance between said current disc head position and said desired track centerline; calculating a driving signal to be applied to said disc head moving means, said driving signal being generally proportional to said minimum possible distance; reducing said driving signal to a maximum value if said driving signal exceeds said maximum value; changing said driving signal to a negative value if said current disc head position is on one side of said desired track centerline; applying said driving signal to said disc head moving means to cause said disc head to move at a velocity generally proportional to said driving signal; and returning to said waiting step.
Claim 2
Independent Claim
210 words
A method for positioning and maintaining a disc head over a desired track centerline on a disc, said disc having a plurality of tracks and embedded servo information associated with each of said tracks, including track identification, said disc rotatably carried on a disc drive having means for moving said disc head, said method comprising the steps of: waiting for a portion of said embedded servo information to pass under said disc head; reading said portion of said embedded servo information; determining the current position of said disc head with an uncertainty of no greater than one-half track width; calculating the minimum possible distance between said current disc head position and said desired track centerline; calculating a driving signal to be applied to said disc head moving means, said driving signal being generally proportional to said minimum possible distance; reducing said driving signal to a maximum value if said driving signal exceeds said maximum value; changing said driving signal to a negative value if said current disc head position is on one side of said desired track centerline; applying said driving signal to said disc head moving means to cause said disc head to move at a velocity generally proportional to said driving signal; and returning to said waiting step.
Claim 3
Dependent Claim
41 words
A method as defined in claim 1 wherein said determining step comprises determining said current disc head position with an uncertainty of no greater than one-quarter track width when said disc head is within one-quarter track width of any track centerline.
Claim 4
Dependent Claim
36 words
A method as defined in claim 2 wherein said determining step comprises determining said current disc head position with substantially no uncertainty when said disc head is within one-quarter track width of said desired track centerline.
Claim 5
Dependent Claim
36 words
A method as defined in claim 1 wherein said determining step comprises determining said current disc head position with substantially no uncertainty when said disc head is within one-quarter track width of said desired track centerline.
Claim 6
Independent Claim
126 words
A method for positioning and maintaining a disc head over a desired track centerline on a disc having a plurality of tracks and embedded servo information associated with each of said tracks including track identification, said disc being rotatably carried on a disc drive having means for moving said disc head, said method comprising the steps of: reading a portion of said embedded servo information; determining the current position of said disc head with an uncertainty of no greater than one-half track width; calculating the minimum possible distance between said current disc head position and said desired track centerline; calculating a driving signal generally proportional to said minimum possible distance; applying said driving signal to said disc head moving means; and returning to said reading step.
Claim 7
Independent Claim
126 words
A method for positioning and maintaining a disc head over a desired track centerline on a disc having a plurality of tracks and embedded servo information associated with each of said tracks including track identification, said disc being rotatably carried on a disc drive having means for moving said disc head, said method comprising the steps of: reading a portion of said embedded servo information; determining the current position of said disc head with an uncertainty of no greater than one-half track width; calculating the minimum possible distance between said current disc head position and said desired track centerline; calculating a driving signal generally proportional to said minimum possible distance; applying said driving signal to said disc head moving means; and returning to said reading step.
Claim 8
Dependent Claim
41 words
A method as defined in claim 5 wherein said determining step comprises determining said current disc head position with an uncertainty of no greater than one-quarter track width when said disc head is within one-quarter track width of any track centerline.
Claim 9
Dependent Claim
36 words
A method as defined in claim 6 wherein said determining step comprises determining said current disc head position with substantially no uncertainty when said disc head is within one-quarter track width of said desired track centerline.
Claim 10
Dependent Claim
36 words
A method as defined in claim 5 wherein said determining step comprises determining said current disc head position with substantially no uncertainty when said disc head is within one-quarter track width of said desired track centerline.
Claim 11
Dependent Claim
18 words
A method as defined in claim 5 further comprising, after said driving signal calculating step, the step of:
Claim 12
Dependent Claim
16 words
reducing said driving signal to a maximum value if said driving signal exceeds said maximum value.
Claim 13
Dependent Claim
16 words
reducing said driving signal to a maximum value if said driving signal exceeds said maximum value.
Claim 14
Dependent Claim
41 words
A method as defined in claim 9 further comprising, after said driving signal calculating step, the step of: changing said driving signal to a negative value if said current disc head position is on one side of said desired track centerline.
Claim 15
Independent Claim
125 words
A method for positioning and maintaining a disc head over a desired track centerline on a disc rotatably carried on a disc drive having means for moving said disc head, said method comprising the steps of: determining the current position of said disc head with an uncertainty of no greater than one-half track width; calculating the minimum possible distance between said current disc position and said desired track centerline; calculating a driving signal to be applied to said disc head moving means, said driving signal being generally proportional to said minimum possible distance; reducing said driving signal to a maximum value if said driving signal exceeds said maximum value; applying said driving signal to said disc head moving means; and returning to said determining step.
Claim 16
Independent Claim
125 words
A method for positioning and maintaining a disc head over a desired track centerline on a disc rotatably carried on a disc drive having means for moving said disc head, said method comprising the steps of: determining the current position of said disc head with an uncertainty of no greater than one-half track width; calculating the minimum possible distance between said current disc position and said desired track centerline; calculating a driving signal to be applied to said disc head moving means, said driving signal being generally proportional to said minimum possible distance; reducing said driving signal to a maximum value if said driving signal exceeds said maximum value; applying said driving signal to said disc head moving means; and returning to said determining step.
Claim 17
Dependent Claim
41 words
A method as defined in claim 11 wherein said determining step comprises determining said current disc head position with an uncertainty of no greater than one-quarter track width when said disc head is within one-quarter track width of any track centerline.
Claim 18
Dependent Claim
36 words
A method as defined in claim 12 wherein said determining step comprises determining said current disc head position with substantially no uncertainty when said disc head is within one-quarter track width of said desired track centerline.
Claim 19
Dependent Claim
36 words
A method as defined in claim 11 wherein said determining step comprises determing said current disc head position with substantially no uncertainty when said disc head is within one-quarter track width of said desired track centerline.
Claim 20
Dependent Claim
41 words
A method as defined in claim 11 further comprising, after said driving signal calculating step, the step of: changing said driving signal to a negative value if said current disc head position is on one side of said desired track centerline.
Claim 21
Dependent Claim
34 words
A method as defined in claim 15 further comprising, after said driving signal calculating step, the step of: reducing said driving signal to a maximum value if said driving signal exceeds said maximum value.
Claim 22
Independent Claim
108 words
A method for positioning and maintaining a disc head over a desired track centerline on a disc rotatably carried on a disc drive having means for moving said disc head, said method comprising the steps of: determining the current position of said disc head with an uncertainty of no greater than one-half track width; calculating the minimum possible distance between said current disc head position and said desired track centerline; calculating a driving signal to be applied to said disc head moving means, said driving signal being generally proportional to said distance; applying said driving signal to said disc head moving means; and returning to said determining step.
Claim 23
Independent Claim
108 words
A method for positioning and maintaining a disc head over a desired track centerline on a disc rotatably carried on a disc drive having means for moving said disc head, said method comprising the steps of: determining the current position of said disc head with an uncertainty of no greater than one-half track width; calculating the minimum possible distance between said current disc head position and said desired track centerline; calculating a driving signal to be applied to said disc head moving means, said driving signal being generally proportional to said distance; applying said driving signal to said disc head moving means; and returning to said determining step.
Claim 24
Dependent Claim
41 words
A method as defined in claim 17 wherein said determining step comprises determining said current disc head position with an uncertainty of no greater than one-quarter track width when said disc head is within one-quarter track width of any track centerline.
Claim 25
Dependent Claim
36 words
A method as defined in claim 18 wherein said determining step comprises determining said current disc head position with substantially no uncertainty when said disc head is within one-quarter track width of said desired track centerline.
Claim 26
Dependent Claim
36 words
A method as defined in claim 17 wherein said determining step comprises determining said current disc head position with substantially no uncertainty when said disc head is within one-quarter track width of said desired track centerline.
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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) | 1987-07-24 | 1988-01-23 | 1988-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-24 | 1992-01-23 | 1992-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-24 | 1996-01-23 | 1996-07-24 | $7700.00 | Window Closed / Lapsed |