US5115664A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tunable feedback transducer for transient friction measurement
Assignee: International Business Machines Corp
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Filing: 1990-06-25
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Granted: 1992-05-26
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Expires: 2010-06-25
Abstract
Abstract A system for measuring transient friction of a head-disk interface in a magnetic disk storage device employs a servo system for accurate measurements. A first movable member carries a slider simulating a magnetic head which rests on a disk when said disk is at rest. The movable member is movably mounted to a second fixed member. A frictionless detector detects a displacement of the movable member relative to a position of the fixed member produced by a force due to friction when the disk spins. A servo system maintains a fixed distance between first and second members in response to an output from the detector and moves the movable member in response thereto. The output is taken from the servo system and provides a signal proportional a force due to friction exerted on said movable member.
Inventors
- 👤 Suryanarayan G. Hegde
- 👤 Anthony P. Praino
- 👤 Steven J. Root
- 👤 Muthuthamby Sri-Jayantha
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:24
CPC Classifications
G; G11; G11B; G11B33/00; G11B33/10; G01; G01N; G01N19/00; G01N19/02; G11B19/00; G11B19/20
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
126 words
A system for measuring transient friction of a head-disk interface in a magnetic disk storage device comprising: a first movable member carrying a slider simulating a magnetic head which rests on a disk when said disk is at rest; a second fixed member to which said movable member is movably attached; frictionless detector means for detecting a displacement of said movable member relative to a position of said fixed member produced by a force due to friction when disk begins to spin; servo means for maintaining a fixed distance between said first and second members in response to an output from said detector; and output means connected to said servo means for generating a signal proportional a force due to friction exerted on said movable member.
Claim 2
Independent Claim
126 words
A system for measuring transient friction of a head-disk interface in a magnetic disk storage device comprising: a first movable member carrying a slider simulating a magnetic head which rests on a disk when said disk is at rest; a second fixed member to which said movable member is movably attached; frictionless detector means for detecting a displacement of said movable member relative to a position of said fixed member produced by a force due to friction when disk begins to spin; servo means for maintaining a fixed distance between said first and second members in response to an output from said detector; and output means connected to said servo means for generating a signal proportional a force due to friction exerted on said movable member.
Claim 3
Dependent Claim
42 words
A system according to claim 1 wherein said first movable member carries an armature and is mounted to pivot around a fixed point in a housing and said second fixed member comprises said housing and includes magnets which interact with said armature.
Claim 4
Dependent Claim
16 words
A system according to claim 2 wherein said frictionless detector means comprises an optical position sensor.
Claim 5
Dependent Claim
27 words
A system according to claim 3 wherein said optical position sensor is a light emitting diode reflecting off a reflector on said movable member to a phototransistor.
Claim 6
Dependent Claim
65 words
A system according to claim 3 wherein said servo means comprises: a controller which converts an output of said optical position sensor into an electronic signal; and a driver which converts said electronic signal into a driving current which is applied to said armature to produce a force that opposes said force due to friction, said output means being connected to receive said electronic signal.
Claim 7
Dependent Claim
37 words
A system according to claim 1 wherein said first movable mount comprises a piezoelectric member which moves in a direction opposite to said force due to friction in response to a driving signal from said servo means.
Claim 8
Dependent Claim
68 words
A system according to claim 6 wherein said servo means comprises: a controller which converts an output of said frictionless detector means into an electronic signal; and a driver which converts said electronic signal into a driving voltage applied to said piezoelectric member to produce a motion that opposes a motion caused by said force due to friction, said output means being connected to receive said electronic signal.
Claim 9
Dependent Claim
16 words
A system according to claim 1 wherein said frictionless detector means comprises an optical position sensor.
Claim 10
Dependent Claim
27 words
A system according to claim 8 wherein said optical position sensor is a light emitting diode reflecting off a reflector on said movable member to a phototransistor.
Claim 11
Dependent Claim
16 words
A system according to claim 1 wherein said frictionless detector means comprises a capacitive position sensor.
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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) | 1995-05-26 | 1995-11-25 | 1996-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-26 | 1999-11-25 | 2000-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-26 | 2003-11-25 | 2004-05-26 | $7700.00 | Window Closed / Lapsed |