Patent US3751693A successfully refreshed from Google Patents.
US3751693A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Moving coil motor with no stray flux
Assignee: Diablo Systems Inc
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Filing: 1972-02-14
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Granted: 1973-08-07
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Expires: 1992-02-14
Abstract
Abstract A voice coil motor for driving the read/write heads of a magnetic disk drive unit includes an outer elongated enclosure of square cross section and an inner enclosure of similar configuration both of which serve as pole pieces for elongated magnets which are affixed to the inner walls of the outer enclosure. The permanent magnets are polarized so that their axes are perpendicular to the coincident center axis of the elongated enclosures. A slidable element is mounted on a rod extending along this center axis, the slidable element driving the read/write head through an aperture in the end plate of the enclosures. An electric coil of square cross section is mounted in an air gap between the inner pole pieces and the permanent magnets by support fingers which extend through slots in the corner of the pole pieces the supports extending from the movable carrier. By this arrangement all of the flux is contained within the rectangular enclosure and practically no stray flux influences the magnetic recording medium.
Inventors
- 👤 A Gabor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:31
CPC Classifications
H; H02; H02K; H02K41/00; H02K41/02; H02K41/035; H02K41/0352; H02K41/0354; H02K41/0356
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
322 words
Apparatus for converting electrical energy into linear mechanical motion comprising: an armature mounted for linear movement along a predetermined axis including an electric coil supported by an elongated slidable element said coil having a predetermined width in the direction of said axis, said coil and element being concentric with said axis; a plurality of magnetic means each having N and S poles along axes perpendicular to said predetermined axis said magnetic means being concentric with said predetermined axis said magnetic means having pole faces elongated in the direction of said axis of a length relatively long compared to said width of said coil; first pole piece means mounted concentrically around said predetermined axis and inside of said magnetic means and forming a magnetic flux path from magnetic poles of a first polarity, said first pole piece means having at least two slots parallel to said predetermined axis; second pole piece means mounted concentrically around said predetermined axis and outside of said magnetic means and forming a magnetic flux path from magnetic poles of a second polarity; magnetically permeable means for completing a magnetic flux path between said first and second pole piecE means; elongated guide means disposed in said predetermined axis for guiding said slidable element; said armature including support means for maintaining said electric coil between said first and second pole piece means including support elements extending through said slots in said first pole piece means connecting said coil to said slidable element said second pole piece means forming a total circumferential enclosure round said magnetic means said enclosure having two open ends, said means for completing a magnetic flux path totally enclosing one of said ends and said other end except for an aperture through which extends said elongated guide means and said slidable element whereby substantially all of the magnetic flux generated by said magnetic means is contained within said second pole piece means and said magnetically permeable means.
Claim 2
Dependent Claim
322 words
Apparatus for converting electrical energy into linear mechanical motion comprising: an armature mounted for linear movement along a predetermined axis including an electric coil supported by an elongated slidable element said coil having a predetermined width in the direction of said axis, said coil and element being concentric with said axis; a plurality of magnetic means each having N and S poles along axes perpendicular to said predetermined axis said magnetic means being concentric with said predetermined axis said magnetic means having pole faces elongated in the direction of said axis of a length relatively long compared to said width of said coil; first pole piece means mounted concentrically around said predetermined axis and inside of said magnetic means and forming a magnetic flux path from magnetic poles of a first polarity, said first pole piece means having at least two slots parallel to said predetermined axis; second pole piece means mounted concentrically around said predetermined axis and outside of said magnetic means and forming a magnetic flux path from magnetic poles of a second polarity; magnetically permeable means for completing a magnetic flux path between said first and second pole piecE means; elongated guide means disposed in said predetermined axis for guiding said slidable element; said armature including support means for maintaining said electric coil between said first and second pole piece means including support elements extending through said slots in said first pole piece means connecting said coil to said slidable element said second pole piece means forming a total circumferential enclosure round said magnetic means said enclosure having two open ends, said means for completing a magnetic flux path totally enclosing one of said ends and said other end except for an aperture through which extends said elongated guide means and said slidable element whereby substantially all of the magnetic flux generated by said magnetic means is contained within said second pole piece means and said magnetically permeable means.
Claim 3
Dependent Claim
46 words
Apparatus as in claim 1 where said first pole piece means is an elongated enclosure of square cross-section with the corners of the square being open to form said slots and said second pole piece means is a similar elongated enclosure but with its corners closed.
Claim 4
Dependent Claim
46 words
Apparatus as in claim 1 where said magnetic means are affixed to said second pole piece means, an air gap between said magnetic means and said first pole piece means providing a magnetic field through which said electric coil moves when energized by an electric current.
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) | 1976-08-06 | 1977-02-05 | 1977-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-06 | 1981-02-05 | 1981-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-06 | 1985-02-05 | 1985-08-07 | $7700.00 | Window Closed / Lapsed |