Magnetic sealing device for use between first and second magnetic members which rotate relative to each other
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
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Nov 10, 1992
Issued Date -
N/A
app pub date -
Dec 2, 1991
filing date -
Sep 29, 1988
priority date (Note) -
Expired
status (Latency Note)
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Abstract
Installed between a housing and a shaft concentrically disposed with a space having a predetermined radial length therebetween so as to move relative to one another is a sealing device which comprises a ferrofluid seal device comprising a permanent magnet and a pair of pole pieces for supporting the magnet interposed therebetween, so that a ferrofluid is retained between the pole pieces at one end thereof and the shaft and that a radially outer air gap is provided at least one of the pole pieces at the other end thereof and the housing, whereby the magnetic flux path extending between the pole pieces at the other end thereof and the housing is eliminated.
First Claim
all claims..Other Claims data not available
Family

- 15 United States
- 10 France
- 8 Japan
- 7 China
- 5 Korea
- 2 Other
Patent Owner(s)
Patent Owner | Address | |
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NIPPON SEIKO KABUSHIKI KAISHA | TOKYO |
International Classification(s)

- 1991 Application Filing Year
- F16C Class
- 419 Applications Filed
- 169 Patents Issued To-Date
- 40.34 % Issued To-Date
Inventor(s)
Inventor Name | Address | # of filed Patents | Total Citations |
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Fujii, Akio | Hujisawa, JP | 119 | 1152 |
# of filed Patents : 119 Total Citations : 1152 |
Cited Art Landscape
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Patent Citation Ranking
- 14 Citation Count
- F16C Class
- 0 % this patent is cited more than
- 33 Age
Forward Cite Landscape
- No Forward Cites to Display

Maintenance Fees
Fee | Large entity fee | small entity fee | micro entity fee | due date |
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Fee | Large entity fee | small entity fee | micro entity fee |
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Surcharge after expiration - Late payment is unavoidable | $700.00 | $350.00 | $175.00 |
Surcharge after expiration - Late payment is unintentional | $1,640.00 | $820.00 | $410.00 |
Full Text

Legal Events
Date | Code | Event | Description |
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Mar 06, 2017 | STCH | INFORMATION ON STATUS: PATENT DISCONTINUATION | free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
Feb 08, 2017 | FP | LAPSED DUE TO FAILURE TO PAY MAINTENANCE FEE | Effective Date: Feb 08, 2017 |
Feb 08, 2017 | LAPS | LAPSE FOR FAILURE TO PAY MAINTENANCE FEES | |
Sep 16, 2016 | REMI | MAINTENANCE FEE REMINDER MAILED | |
Feb 08, 2013 | SULP | SURCHARGE FOR LATE PAYMENT | year of fee payment: 7 |
Feb 08, 2013 | FPAY | FEE PAYMENT | year of fee payment: 8 |
Sep 24, 2012 | REMI | MAINTENANCE FEE REMINDER MAILED | |
Feb 06, 2009 | FPAY | FEE PAYMENT | year of fee payment: 4 |
Feb 06, 2009 | SULP | SURCHARGE FOR LATE PAYMENT | |
Aug 18, 2008 | REMI | MAINTENANCE FEE REMINDER MAILED | |
Feb 08, 2005 | I | Issuance | |
Oct 16, 2003 | P | Published | |
May 13, 2003 | F | Filing | |
Apr 27, 1998 | PD | Priority Date |

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