Patent US3838457A successfully refreshed from Google Patents.
US3838457A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Track seeking and following servo system
Assignee: International Business Machines Corp
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Filing: 1973-07-05
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Granted: 1974-09-24
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Expires: 1993-07-05
Abstract
Abstract In a magnetic disk recording device, a track following system for detecting servo signals to distinguish one track from another within a repeating group of tracks and to add a biasing signal to said detected signal whenever the transducing head is located more than one-half track from the target track. Means for producing a position error signal of linear slope over the group number of tracks is disclosed enabling the electrical offsetting of the transducing head up to one-half the group number of tracks by modifying the position error signal. Seeking means are provided to rapidly move the transducing head toward the target track from a position more than plus or minus one-half the group number of tracks and means are provided for counting the group number and the track number within the group.
Inventors
- 👤 R Palmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:55
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/54; G11B5/55; G11B5/5521; G11B5/5552; G11B5/5556
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
170 words
In a servo system for positioning transducing heads to transmit work data from and to one of a plurality of data bearing tracks and to read servo data from said tracks, a servo system comprising: seeking means for rapidly moving a selected transducing head from a present location toward a target data track, means for transferring control from said seeking means to track following means when said selected transducing head has approached to within a selected definite number of tracks more than one-half track from said target track, and track following means for homing said selected transducing head on said target track within said selected definite number of tracks and thereafter maintaining said head in accurate registration with said target track, said track following means including biasing means and summing means connected by gating means to provide a sum of a signal from said biasing means with a signal from said selected transducing head to provide a position error signal of linear slope over said selected definite number of tracks.
Claim 2
Dependent Claim
170 words
In a servo system for positioning transducing heads to transmit work data from and to one of a plurality of data bearing tracks and to read servo data from said tracks, a servo system comprising: seeking means for rapidly moving a selected transducing head from a present location toward a target data track, means for transferring control from said seeking means to track following means when said selected transducing head has approached to within a selected definite number of tracks more than one-half track from said target track, and track following means for homing said selected transducing head on said target track within said selected definite number of tracks and thereafter maintaining said head in accurate registration with said target track, said track following means including biasing means and summing means connected by gating means to provide a sum of a signal from said biasing means with a signal from said selected transducing head to provide a position error signal of linear slope over said selected definite number of tracks.
Claim 3
Dependent Claim
17 words
The system of claim 1 wherein said servo data is on separate tracks from said work data.
Claim 4
Dependent Claim
93 words
The system of claim 1 wherein said servo data is interspersed with said work data on the same tracks, wherein means recorded in said servo data identify tracks within a repeating group of tracks, wherein said seeking means includes means to count the group number so that said group number and a track number within said group identifies the specific track over which said selected transducing head is situated at least once in each group of tracks, and means to produce a reference signal when said head enters each successive group of tracks.
Claim 5
Dependent Claim
49 words
The system of claim 1 in which means are provided to modify said position error signal in accordance with an offsetting signal so that said head can be caused to follow a track offset from said target track within plus or minus one-half said selected definite number of tracks.
Claim 6
Dependent Claim
67 words
The system of claim 1 wherein said track following means further includes a decoder for supplying successive signals to said gating means, said gating means operated in a sequence determined by said successive signals from said decoder for passing servo signals from said selected transducing head to said summing means when said servo signal and a signal from said decoder are both present at said gating means.
Claim 7
Dependent Claim
119 words
In a servo system for positioning transducing heads to transmit work data from and to one of a plurality of data bearing tracks and to read servo data from said tracks, seeking means to move a head from a present position toward a target track comprising means recorded in said servo data to identify tracks within a repeating group of tracks, means to count the group number so that said group number and a track number within said group identifies the specific track over which said head is situated at least once in each group of tracks, and an oscillator means to produce a reference signal for said counting means when said head enters each successive grouP of tracks.
Claim 8
Dependent Claim
119 words
In a servo system for positioning transducing heads to transmit work data from and to one of a plurality of data bearing tracks and to read servo data from said tracks, seeking means to move a head from a present position toward a target track comprising means recorded in said servo data to identify tracks within a repeating group of tracks, means to count the group number so that said group number and a track number within said group identifies the specific track over which said head is situated at least once in each group of tracks, and an oscillator means to produce a reference signal for said counting means when said head enters each successive grouP of tracks.
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) | 1977-09-23 | 1978-03-25 | 1978-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-23 | 1982-03-25 | 1982-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-23 | 1986-03-25 | 1986-09-24 | $7700.00 | Window Closed / Lapsed |