US4724392A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for testing magnetic head/disk interfaces
Assignee: International Business Machines Corp
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Filing: 1986-04-28
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Granted: 1988-02-09
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Expires: 2006-04-28
Abstract
Abstract Method for measuring the properties of a slider/disk interface in a magnetic disk storage apparatus by measuring a triboelectric current flowing between disk and slider. Rotational speed is adjusted between 100 and 500 rpm so as to obtain a frictional contact between disk and slider. The shape of the tribo current curve obtained during the measuring time interval is analyzed. An early maximum of the tribo current amplitude and a subsequent continual decay indicates a good slider/disk interface and a long lifetime.
Inventors
- 👤 Upali Bandara
- 👤 Gerhard Elsner
- 👤 Volker Heinrich
- 👤 Holger Hinkel
- 👤 Artur Lang
- 👤 Erwin Prinz
- 👤 Werner Steiner
- 👤 Werner Zapka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:02
CPC Classifications
G; G11; G11B; G11B33/00; G11B33/10; G11B17/00; G11B17/32; G11B5/00; G11B5/012; G11B5/48; G11B5/58
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
101 words
Method for measuring and testing the properties of the interface of a slider carrying a magnetic transducer head and a disk in a magnetic disk storage apparatus comprising the steps of: adjusting the rotational speed of the disk such that there is a rubbing contact between the slider and the disk, generating a triboelectric current between disk and slider in accordance with said step of adjusting the rotational speed measuring said triboelectric current amplitude during a measuring/testing time period, plotting a graph of the amplitude of said triboelectric current over said measuring/testing time period thereby indicating the properties of the interface.
Claim 2
Dependent Claim
101 words
Method for measuring and testing the properties of the interface of a slider carrying a magnetic transducer head and a disk in a magnetic disk storage apparatus comprising the steps of: adjusting the rotational speed of the disk such that there is a rubbing contact between the slider and the disk, generating a triboelectric current between disk and slider in accordance with said step of adjusting the rotational speed measuring said triboelectric current amplitude during a measuring/testing time period, plotting a graph of the amplitude of said triboelectric current over said measuring/testing time period thereby indicating the properties of the interface.
Claim 3
Dependent Claim
31 words
Method according to claim 1 further comprising the step of analyzing said graph to identify when an early maximum value or a continuous increase of the triboelectric current curve is detected.
Claim 4
Dependent Claim
28 words
Method according to claim 2 wherein during the step of analyzing said graph an early maximum indicates a good slider, and a continuous increase indicates a normal slider.
Claim 5
Dependent Claim
38 words
Method according to claim 2 wherein an indication of the expected lifetime of the slider and cooperating disk is obtained by a decrease of the curve of said graph to a defined percentage (e.g. 10%) of the maximum.
Claim 6
Dependent Claim
20 words
Method according to claim 1 wherein the step of adjusting the rotational speed comprises setting the speed to 100-105 rpm.
Claim 7
Dependent Claim
15 words
Method according to claim 1 wherein the disk is lubed with a fluor containing material.
Claim 8
Dependent Claim
21 words
Method according to claim 1 wherein measurements on both sides of a disk are performed and compared to detect disk side-asymmetries.
Claim 9
Dependent Claim
38 words
Method according to claim 1 further comprising the step of analyzing the plot of said graph to determine the occurrence of jumps in the triboelectric current curve which provide an indication of the slackness of the spindle bearing.
Claim 10
Dependent Claim
24 words
Method according to claim 1 wherein the slider contains a ceramics mixture of aluminum oxide (Al 2 O 3 ) and titan carbide (TiC).
Claim 11
Dependent Claim
27 words
Method according to claim 1, wherein the magnetic disk comprises a particular coating with iron oxide (Fe 2 O 3 ) particles in a synthetic substance solution.
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) | 1991-02-08 | 1991-08-10 | 1992-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-08 | 1995-08-10 | 1996-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-08 | 1999-08-10 | 2000-02-09 | $7700.00 | Window Closed / Lapsed |