US4937545A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System of permanent magnets for an intense magnetic field
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
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Filing: 1988-03-02
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Granted: 1990-06-26
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Expires: 2008-03-02
Abstract
Abstract PCT No. PCT/FR88/00116 Sec. 371 Date Nov. 1, 1988 Sec. 102(e) Date Nov. 1, 1988 PCT Filed Mar. 2, 1988 PCT Pub. No. WO88/06798 PCT Pub. Date Sep. 7, 1988.Permanent magnets for producing an intense field. A main magnetic circuit comprises two magnets (1, 1'), two pole pieces (2, 2') and a yoke (3). Two additional magnets (6, 6') of opposite magnetization reinforce the field in the air gap (5) while extending into the latter between edges (25, 25', 26, 26', 27, 27', 28, 28') of magnets (1, 1') and pole pieces (2, 2'). Application to imaging by magnetic resonance (tomography).
Inventors
- 👤 Jean-Jacques Chaillout
- 👤 Christian Jeandey
- 👤 Edmond Tournier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:07
CPC Classifications
H; H01; H01F; H01F7/00; H01F7/02; H01F7/0273; H01F7/0278; H01F7/0284; G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/383
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
160 words
System of permanent magnets having a permeable magnetic yoke (3) formed by two opposite support walls (21, 21') and connected by two connecting walls (22, 22'), two main permanet magnets (1, 1') of the same magnetization direction disposed on the support walls (21, 21') within the yoke (3) and whereof the facing surfaces (20, 20') carry opposite poles, two permeable magnetic plates (2, 2') on the facing surfaces (20, 20') and which define an air gap (5) and two lateral permanent magnets (6, 6') whose magnetization direction is opposite to that of the main permanent magnets (1, 1') and which also define the air gap (5), being positioned facing the connecting walls (22, 22') and within the yoke (3), characterized in that the lateral permanent magnets (6, 6') extend laterally between the permeable magnetic plates (2, 2'), so as to be positioned facing the lateral edges of the main permanent magnets (1, 1') and the permeable magnetic plates (2, 2').
Claim 2
Dependent Claim
160 words
System of permanent magnets having a permeable magnetic yoke (3) formed by two opposite support walls (21, 21') and connected by two connecting walls (22, 22'), two main permanet magnets (1, 1') of the same magnetization direction disposed on the support walls (21, 21') within the yoke (3) and whereof the facing surfaces (20, 20') carry opposite poles, two permeable magnetic plates (2, 2') on the facing surfaces (20, 20') and which define an air gap (5) and two lateral permanent magnets (6, 6') whose magnetization direction is opposite to that of the main permanent magnets (1, 1') and which also define the air gap (5), being positioned facing the connecting walls (22, 22') and within the yoke (3), characterized in that the lateral permanent magnets (6, 6') extend laterally between the permeable magnetic plates (2, 2'), so as to be positioned facing the lateral edges of the main permanent magnets (1, 1') and the permeable magnetic plates (2, 2').
Claim 3
Dependent Claim
40 words
System of permanent magnets according to claim 1, characterized in that the support walls are horizontal, the connecting walls vertical, the main and lateral permanent magnets parallelepipedic and the air gap parallelepipedic and open on two opposite sides (23, 23').
Claim 4
Dependent Claim
27 words
System of permanent magnets according to either of the claims 1 and 2, characterized in that the main permanent magnets (1, 1') extend beyond plates (2, 2').
Claim 5
Dependent Claim
22 words
System of permanent magnets according to claim 1, characterized in that the lateral permanent magnets (6, 6') extend beyond plates (2, 2').
Claim 6
Dependent Claim
35 words
System of permanent magnets according to claim 1, characterized in that it comprises mechanical means (15, 16) for varying the position of the lateral permanent magnets (6, 6') with respect to the plates (2, 2').
References Cited (Backward Citations)
US3437963A
Cited
FR2168233A1
Cited
EP0161782A1
Cited
EP0170318A1
Cited
US4777464A
Cited
EP1464656A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-06-25 | 1993-12-25 | 1994-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-25 | 1997-12-25 | 1998-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-25 | 2001-12-25 | 2002-06-26 | $7700.00 | Window Closed / Lapsed |