US5396136A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic field levitation
Assignee: SRI International Inc
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Filing: 1992-10-28
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Granted: 1995-03-07
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Expires: 2012-10-28
Abstract
Abstract Various levitation devices are disclosed in which an array of permanent magnets is levitated by magnetic interaction with a diamagnetic material. Levitation is achieved without using a fixed permanent magnet or other device to supplement the magnetic field of the array. The cost and design constraints resulting from undesirable spring constants produced by such permanent magnets are thereby avoided.
Inventors
- 👤 Ronald E. Pelrine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:21
CPC Classifications
H; H02; H02N; H02N15/00; H02N15/04; F; F16; F16C; F16C32/00; F16C32/04; F16C32/0406; F16C32/0408; F16C32/0436; F16C32/0438; G; G01; G01C; G01C9/00; G01C9/02; G01C9/06; G01C9/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
145 words
A method of levitating a magnetic member relative to the gravitational attraction of the earth comprising the steps of: arranging a plurality of magnets to form a first member comprised of said magnets having both a high magnetic strength and high magnetic gradient adjacent a predetermined portion of said first member, wherein said step of arranging comprises disposing said magnets in a consecutive sequence with each two consecutive magnets having opposite magnetic polarity; providing a second member comprised of a diamagnetic material having a relative magnetic permeability less than one at ambient temperatures; and positioning said first and second members proximate each other with said predetermined portion of said first member facing said second member, whereat magnetic interaction between said members levitates said first member relative to a full gravitational attraction of at least 1 g without requiring magnetic field supplement from another magnetic source.
Claim 2
Independent Claim
145 words
A method of levitating a magnetic member relative to the gravitational attraction of the earth comprising the steps of: arranging a plurality of magnets to form a first member comprised of said magnets having both a high magnetic strength and high magnetic gradient adjacent a predetermined portion of said first member, wherein said step of arranging comprises disposing said magnets in a consecutive sequence with each two consecutive magnets having opposite magnetic polarity; providing a second member comprised of a diamagnetic material having a relative magnetic permeability less than one at ambient temperatures; and positioning said first and second members proximate each other with said predetermined portion of said first member facing said second member, whereat magnetic interaction between said members levitates said first member relative to a full gravitational attraction of at least 1 g without requiring magnetic field supplement from another magnetic source.
Claim 3
Dependent Claim
54 words
The method of claim 1 in which: said step of providing said second member provides a diamagnetic member comprised of either graphite or bismuth; and said step of positioning said first and second members provides a magnetic interaction that levitates said first member relative to a full gravitational attraction of at least 1 g.
Claim 4
Dependent Claim
121 words
The method of claim 1 in which: said step of arranging said magnets comprises arranging a plurality of permanent magnets, each formed from a strongly magnetic material and each having a north magnetic pole and a south magnetic pole separated by a straight line section of magnetic material, into a consecutive sequence in which each two consecutive magnets define a closed loop magnetic flux path that intercepts both of said magnetic poles of said two consecutive magnets; and said step of positioning said first and second members comprises positioning said members such that a geometric extension of said straight line separation of said magnetic north and south poles for each of said magnets defines a direction that intercepts said second member.
Claim 5
Dependent Claim
56 words
The method of claim 3 in which said step of arranging said magnets comprises arranging magnets having a first dimension parallel to said separation of said north and south magnetic poles and a second dimension perpendicular to said first dimension and a ratio of said first dimension to said second dimension between about 0.3 and 0.8.
Claim 6
Dependent Claim
93 words
The method of claim 3 in which: said step of arranging magnets provides plurality of disk shaped first members that are substantially identical to each other and disposed at spaced intervals along a shaft; said step of providing said second member provides a plurality of disk shaped second members comprised of said diamagnetic material that are disposed at spaced intervals from each other; and said step of positioning said first and second members comprises positioning said first and second disk shaped members such that they are interleaved and substantially parallel to each other.
Claim 7
Dependent Claim
26 words
The method of claim 1 further including the step of moving said first member relative to said second member by magnetic interaction with said first member.
Claim 8
Dependent Claim
22 words
The method of claim 1 further including the step of sensing the position of said first member relative to said second member.
References Cited (Backward Citations)
US3225608A
Cited
US3447842A
Cited
US3465598A
Cited
US3492738A
Cited
US3493274A
Cited
US3552028A
Cited
US3874750A
Cited
US3815963A
Cited
US3831287A
Cited
US4082376A
Cited
US4381875A
Cited
US4541772A
Cited
US4583794A
Cited
US4620752A
Cited
JPS6438605A
Cited
US5126610A
Cited
US5126317A
Cited
JPH03103086A
Cited
US5177387A
Cited
US5220232A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-03-06 | 1998-09-05 | 1999-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-03-06 | 2002-09-05 | 2003-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-03-06 | 2006-09-05 | 2007-03-07 | $7700.00 | Window Closed / Lapsed |