US4827162A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Controlled drag for magnet actuator
Assignee: Unisys Corp
•
Filing: 1987-03-02
•
Granted: 1989-05-02
•
Expires: 2007-03-02
Abstract
Abstract A disk drive actuator including automatic eddy-current braking capability, enhanced by simple modifications of coil-mount structure, such as split damping ring DR and spaced-rib array, this array shown for example in FIG. 12 (see DR-R).
Inventors
- 👤 Frank I. Morris
- 👤 Whitney B. Kroetz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:51
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/54; G11B5/55; G11B5/5521; H; H02; H02K; H02K41/00; H02K41/02; H02K41/035; H02K41/0352; H02K41/0354; H02K41/0356
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
127 words
A voice coil linear actuator including a prescribed drive coil structure mount on coil-mount means and arranged to be normally thrust thru magnetic flux at a prescribed range of speeds whereby appreciable eddy-current is generated on at least a portion of the coil-mount means, this portion including conductive connect means spaced from said coil structure and conductive bridge means connecting said connect means to said drive coil structure; said connect means including dielectric impedance means comprising gapped-ring means intersecting at least one eddy current path; and said bridge means being formed to exhibit high impedance in conducting eddy current, said bridge means comprising an array of identical spaced narrow metal ribs whose cross-section is sufficiently reduced to enhance eddy drag voltage at actuator speeds above said range.
Claim 2
Dependent Claim
127 words
A voice coil linear actuator including a prescribed drive coil structure mount on coil-mount means and arranged to be normally thrust thru magnetic flux at a prescribed range of speeds whereby appreciable eddy-current is generated on at least a portion of the coil-mount means, this portion including conductive connect means spaced from said coil structure and conductive bridge means connecting said connect means to said drive coil structure; said connect means including dielectric impedance means comprising gapped-ring means intersecting at least one eddy current path; and said bridge means being formed to exhibit high impedance in conducting eddy current, said bridge means comprising an array of identical spaced narrow metal ribs whose cross-section is sufficiently reduced to enhance eddy drag voltage at actuator speeds above said range.
Claim 3
Dependent Claim
70 words
A linear actuator including coil means mounted on metallic drum means this drum means exhibiting eddy-currents during electromagnetic excitation of the coil means, this drum means including impedance-enhancing grapped-ring means selected and arranged to enhance eddy-current to the point where it produces a drage voltage apt for reducing actuator speed above prescribed maximum speed, this gapped-ring means comprising a cylindrical ring portion having at least one impedance-enhancing dielectric gap thereacross.
Claim 4
Dependent Claim
70 words
A linear actuator including coil means mounted on metallic drum means this drum means exhibiting eddy-currents during electromagnetic excitation of the coil means, this drum means including impedance-enhancing grapped-ring means selected and arranged to enhance eddy-current to the point where it produces a drage voltage apt for reducing actuator speed above prescribed maximum speed, this gapped-ring means comprising a cylindrical ring portion having at least one impedance-enhancing dielectric gap thereacross.
Claim 5
Dependent Claim
60 words
The invention of claim 1 wherein the coil mount means is of nonmagnetic metal and cylindrical including a cylindrical bobbin portion and a cylindrical connect ring spaced therefrom, this ring including at least one dielectric gap of prescribed elevated impedance whereby to generate a prescribed braking eddy current at a prescribed actuator crash-speed, well above said normal range of speeds.
Claim 6
Dependent Claim
43 words
The invention of claim 3 wherein said bridge means comprises said array of ribs which are disposed equi-spaced about a cylindrical plane approximating the periphery of said bobbin, the rib cross-section being set to render a prescribed braking eddy current at said crash-speed.
Claim 7
Dependent Claim
25 words
The invention of claim 4 wherein the said coil mount means, including bobbin, ribs and ring portions, is composed of aluminium or an aluminum alloy.
Claim 8
Dependent Claim
25 words
The invention of claim 5 wherein said coil mount means is carried on a carriage structure disposed radially inward thereof, being coupled to said ring.
Claim 9
Dependent Claim
16 words
The invention of claim 6 wherein said impedance gap in said ring is an air gap.
Claim 10
Dependent Claim
29 words
The invention of claim 7 wherein said ring is somewhat smaller in diameter than said bobbin, and carries connector-current means selected and arranged to mount a flexible coil-current-conductor means.
Claim 11
Independent Claim
105 words
A method of arranging a voice coil linear actuator to exhibit automatic eddy-current braking at a prescribed "excess-speed" well above its normal operating speed, this actuator comprising bobbin means, a drive coil wound on this bobbin means, and arranged to operate within prescribed magnetic flux; damping ring means spaced from the bobbin means, and cylindrical connect means joining said bobbin means to said ring means, this method comprising: cutting thru the cross-section of said ring means to create one or several impedance gaps; such that when said actuator is traversing said flux at said "excess-speed" sufficient eddy-current will be generated to radically reduce actuator speed.
Claim 12
Independent Claim
105 words
A method of arranging a voice coil linear actuator to exhibit automatic eddy-current braking at a prescribed "excess-speed" well above its normal operating speed, this actuator comprising bobbin means, a drive coil wound on this bobbin means, and arranged to operate within prescribed magnetic flux; damping ring means spaced from the bobbin means, and cylindrical connect means joining said bobbin means to said ring means, this method comprising: cutting thru the cross-section of said ring means to create one or several impedance gaps; such that when said actuator is traversing said flux at said "excess-speed" sufficient eddy-current will be generated to radically reduce actuator speed.
Claim 13
Independent Claim
109 words
A method of arranging a voice coil linear actuator to exhibit automatic eddy-current braking at a prescribed "excess-speed" well above its normal operating speed, this actuator comprising bobbin means, a drive coil wound on this bobbin means, and arranged to operate within a prescribed magnetic flux; damping ring means spaced from the bobbin means, and cylindrical connect means joining said bobbin means to said ring means, this method comprising: Configuring said connect means as narrow ribs spaced equidistant about the bobbin means and exhibiting sufficiently narrow cross-section so that when said actuator is traversing said flux at said "excess-speed" sufficient eddy-current will be generated to radically reduce actuator speed.
Claim 14
Independent Claim
109 words
A method of arranging a voice coil linear actuator to exhibit automatic eddy-current braking at a prescribed "excess-speed" well above its normal operating speed, this actuator comprising bobbin means, a drive coil wound on this bobbin means, and arranged to operate within a prescribed magnetic flux; damping ring means spaced from the bobbin means, and cylindrical connect means joining said bobbin means to said ring means, this method comprising: Configuring said connect means as narrow ribs spaced equidistant about the bobbin means and exhibiting sufficiently narrow cross-section so that when said actuator is traversing said flux at said "excess-speed" sufficient eddy-current will be generated to radically reduce actuator speed.
Claim 15
Dependent Claim
52 words
The invention of claim 2 wherein said drum includes an elongated, somewhat-cylindrical portion extended axially from said coil means, this extended portion including a relieved portion therealong defined by an array of relatively narrow-cross section ribs separated from one another and providing eddy-current impedance-enhancement as well as increased resistance to heat flow.
Claim 16
Dependent Claim
71 words
The invention of claim 2 wherein said drum includes an elongate, somewhat-cylindrical portion extended axially from said coil means, this extended portion including a relieved portion therealong defined by an array of relatively narrow-cross section ribs separated from one another and providing eddy-current impedance-enhancement as well as increased resistance to heat flow; said ring portion being disposed at the drum end opposite said coil means, separated therefrom by said relieved portion.
References Cited (Backward Citations)
US3617673A
Cited
US3666977A
Cited
US3827081A
Cited
US3922501A
Cited
US3984706A
Cited
US4287445A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-01 | 1992-10-31 | 1993-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-01 | 1996-10-31 | 1997-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-01 | 2000-10-31 | 2001-05-02 | $7700.00 | Window Closed / Lapsed |