Patent US5880587A successfully refreshed from Google Patents.
US5880587A
Expired / Lapsed
US
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Method and apparatus for performing in file slider take-off measurements through tuned external AE detection
Assignee: HGST Netherlands BV
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Filing: 1997-02-03
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Granted: 1999-03-09
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Expires: 2017-02-03
Abstract
Abstract An acoustic emission technique and apparatus that determines the take-off velocity of a slider based upon a quantitative measurement of slider velocity without internal access to the file. The system includes a vibration detector for detecting contact energy, and for producing an output signal; and a logic circuit coupled to the vibration detector, for processing the output signal from the vibration detector to identify a slider take-off velocity. The slider take-off velocity is derived by multiplying lambda by the characteristic frequency, where lambda is the spacing between bumps in a circumferential direction. The output signal of the vibration detector disappears when the slider clears the landing zone. The vibration detector is attached to the actuator screw or other vibration transfer features accessible from outside the disk drive.
Inventors
- 👤 James William Annis
- 👤 Linden James Crawforth
- 👤 Erhard Theodor Schreck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:05
CPC Classifications
G; G11; G11B; G11B33/00; G11B33/02; G11B33/08; G11B21/00; G11B21/02; G11B21/12; G11B21/16; G11B21/20; G11B21/21
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
96 words
A slider take-off velocity determination apparatus, comprising: a vibration detector for detecting contact energy between a slider and projections of a known spacing on a disk surface and for producing an output signal having a frequency component corresponding to the rate that the slider contacts the projections; and a logic circuit, coupled to the vibration detector for processing the output signal from the vibration detector to identify a slider take-off velocity, the slider take-off velocity corresponding to the velocity of the slider relative to disk where the slider glides above the projections without contacting the projections.
Claim 2
Dependent Claim
96 words
A slider take-off velocity determination apparatus, comprising: a vibration detector for detecting contact energy between a slider and projections of a known spacing on a disk surface and for producing an output signal having a frequency component corresponding to the rate that the slider contacts the projections; and a logic circuit, coupled to the vibration detector for processing the output signal from the vibration detector to identify a slider take-off velocity, the slider take-off velocity corresponding to the velocity of the slider relative to disk where the slider glides above the projections without contacting the projections.
Claim 3
Dependent Claim
30 words
The apparatus of claim 1 wherein the slider take-off velocity is derived by multiplying lambda by the characteristic frequency, where lambda is the spacing between projections in a circumferential direction.
Claim 4
Dependent Claim
21 words
The apparatus of claim 1 where the output signal of the vibration detector disappears when the slider clears the disk surface.
Claim 5
Dependent Claim
26 words
The apparatus of claim 1 wherein the vibration detector is attached to a vibrating structural feature of the disk drive accessible from outside the disk drive.
Claim 6
Dependent Claim
22 words
The apparatus of claim 1 wherein the vibration detector comprises an acoustic emission (AE) sensor, an accelerometer, or a laser doppler vibrometer.
Claim 7
Dependent Claim
27 words
The apparatus of claim 1 wherein the acoustic emission sensor is attached to a vibrating structural feature of the disk drive accessible from outside the disk drive.
Claim 8
Dependent Claim
21 words
The apparatus of claim 6 wherein the actuator screw is accessible through an opening in an enclosure enclosing the disk drive.
Claim 9
Dependent Claim
36 words
The apparatus of claim 1 wherein the logic circuit comprises a frequency filter having a predetermined cut-off frequency to signal when all sliders in the disk drive have not taken off at the predetermined cut-off frequency.
Claim 10
Dependent Claim
30 words
The apparatus of claim 1 wherein the logic circuit comprises a filter adjusted to a fixed frequency corresponding to a desired slider take-off velocity, thereby acting as a go/no-go indicator.
Claim 11
Dependent Claim
15 words
The apparatus of claim 1 wherein the projections of a known spacing comprise laser bumps.
Claim 12
Dependent Claim
20 words
The apparatus of claim 10 wherein the laser bumps are disposed in a landing zone of a textured disk surface.
Claim 13
Dependent Claim
170 words
A disk drive system, comprising: a disk having a recording area and a landing zone, the landing zone including projections of a known spacing for providing a durable, low stiction region for start/stop operation; a magnetic sensor including a slider and magnetic head, operatively coupled to the disk, for reading data from and writing data to the recording area; a suspension assembly, coupled to the magnetic sensor, for supporting the magnetic sensor; an actuator assembly, coupled to the suspension assembly, for controlling the movement of the magnetic sensor relative to the disk, the actuator assembly positioning the magnetic sensor over the landing zone prior to a stop operation; a vibration sensor, coupled to the actuator assembly, for detecting energy associated with contact between the slider and the projections in the landing zone upon spinup of the disk; and logic circuit, coupled to the vibration sensor, for receiving a signal from the vibration sensor having a characteristic frequency component representing the energy and processing the signal to identify a take-off velocity.
Claim 14
Dependent Claim
170 words
A disk drive system, comprising: a disk having a recording area and a landing zone, the landing zone including projections of a known spacing for providing a durable, low stiction region for start/stop operation; a magnetic sensor including a slider and magnetic head, operatively coupled to the disk, for reading data from and writing data to the recording area; a suspension assembly, coupled to the magnetic sensor, for supporting the magnetic sensor; an actuator assembly, coupled to the suspension assembly, for controlling the movement of the magnetic sensor relative to the disk, the actuator assembly positioning the magnetic sensor over the landing zone prior to a stop operation; a vibration sensor, coupled to the actuator assembly, for detecting energy associated with contact between the slider and the projections in the landing zone upon spinup of the disk; and logic circuit, coupled to the vibration sensor, for receiving a signal from the vibration sensor having a characteristic frequency component representing the energy and processing the signal to identify a take-off velocity.
Claim 15
Dependent Claim
32 words
The disk drive system of claim 12 wherein the slider take-off velocity is derived by multiplying lambda by the characteristic frequency, where lambda is the spacing between projections in a circumferential direction.
Claim 16
Dependent Claim
23 words
The disk drive system of claim 12 where the output signal of the vibration sensor disappears when the slider clears the landing zone.
Claim 17
Dependent Claim
26 words
The disk drive system of claim 12 wherein the vibration sensor is attached to a portion of the actuator assembly accessible from outside the disk drive.
Claim 18
Dependent Claim
24 words
The disk drive system of claim 12 wherein the vibration sensor comprises an acoustic emission (AE) sensor, an accelerometer, or a laser doppler vibrometer.
Claim 19
Dependent Claim
25 words
The disk drive system of claim 12 wherein the acoustic emission sensor is attached to a vibrating portion of the disk drive accessible from outside.
Claim 20
Dependent Claim
23 words
The disk drive system of claim 17 wherein the vibrating portion is accessible through an opening in a cover of the disk drive.
Claim 21
Dependent Claim
38 words
The disk drive system of claim 12 wherein the logic circuit comprises a frequency filter having a predetermined cut-off frequency to alert when the slider in the disk drive has not taken off at the predetermined cut-off frequency.
Claim 22
Dependent Claim
31 words
The disk drive system of claim 12 wherein the logic circuit comprises a filter adjusted to a fixed frequency corresponding to a desired take-off velocity, thereby acting as a go/no-go indicator.
Claim 23
Dependent Claim
17 words
The disk drive system of claim 12 wherein the projections of a known spacing comprise laser bumps.
Claim 24
Independent Claim
76 words
A method of determining a slider take-off velocity, comprising the steps of: detecting contact energy between a slider and projections of a known spacing in a landing zone of a disk using a vibration detector; producing an output signal for the vibration detector having a frequency component corresponding to the rate that the slider contacts a projections in the landing zone; and processing the output signal from the vibration detector to identify a slider take-off velocity.
Claim 25
Independent Claim
76 words
A method of determining a slider take-off velocity, comprising the steps of: detecting contact energy between a slider and projections of a known spacing in a landing zone of a disk using a vibration detector; producing an output signal for the vibration detector having a frequency component corresponding to the rate that the slider contacts a projections in the landing zone; and processing the output signal from the vibration detector to identify a slider take-off velocity.
Claim 26
Dependent Claim
31 words
The method of claim 22 wherein the slider take-off velocity corresponds to the velocity of the slider relative to disk where the slider glides above the projections without contacting the projections.
Claim 27
Dependent Claim
33 words
The method of claim 22 further comprising the step of deriving the slider take-off velocity by multiplying lambda by the characteristic frequency, where lambda is the spacing between projections in a circumferential direction.
Claim 28
Dependent Claim
28 words
The method of claim 22 further comprising the step of associating the disappearance of the output signal of the vibration detector with the slider clearing the landing zone.
Claim 29
Dependent Claim
31 words
The method of claim 22 wherein the step of detecting contact energy further comprises attaching the vibration detector to a portion of an actuator assembly accessible from outside the disk drive.
Claim 30
Dependent Claim
21 words
The method of claim 22 wherein the actuator assembly is accessible through an opening in a cover of the disk drive.
Claim 31
Dependent Claim
22 words
The method of claim 22 wherein the vibration detector comprises an acoustic emission (AE) sensor, an accelerometer, or a laser doppler vibrometer.
Claim 32
Dependent Claim
45 words
The method of claim 22 wherein the processing step further comprises the step of filtering the output signal through a frequency filter having a predetermined cut-off frequency to alert when the slider in the disk drive has not taken off at the predetermined cut-off frequency.
Claim 33
Dependent Claim
38 words
The method of claim 22 wherein the processing step further comprises the step of filtering the output signal through a filter adjusted to a fixed frequency corresponding to a desired take-off velocity, thereby acting as a go/no-go indicator.
References Cited (Backward Citations)
US3713130A
Cited
US3688287A
Cited
JPS58141468A
Cited
US4532802A
Cited
JPS62132282A
Cited
US4795981A
Cited
US4812927A
Cited
JPH02252101A
Cited
US5168412A
Cited
JPH06139737A
Cited
US5545989A
Cited
US5594595A
Cited
US5742446A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-03-08 | 2002-09-07 | 2003-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-03-08 | 2006-09-07 | 2007-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-03-08 | 2010-09-07 | 2011-03-09 | $7700.00 | Window Closed / Lapsed |