Patent US4803426A successfully refreshed from Google Patents.
US4803426A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic tilt sensor
Assignee: TDK Corp
•
Filing: 1987-07-16
•
Granted: 1989-02-07
•
Expires: 2007-07-16
Abstract
Abstract A magnetic tilt sensor in which a permanent magnet having a surface coated with a magnetic fluid is housed in a space inside a nonmagnetic case and is freely movable, and a magnetic sensing element is disposed to oppose the space through the case. When the case is tilted, the permanent magnet inside the space is moved to a lower position, and hence magnetism detected by the magnetic sensing element changes, thereby detecting a tilt of the case.
Inventors
- 👤 Yoshimoto Odagawa
- 👤 Yasushi Yanagisawa
- 👤 Hiraku Imaizumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:25
CPC Classifications
G; G01; G01C; G01C9/00; G01C9/10; G01C9/02; G01C9/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
103 words
A magnetic tilt sensor comprising: a nonmagnetic case having a space therein, a permanent magnet housed to freely movable in said space, a magnetic fluid attracted to said permanent magnet, said magnetic fluid being of an amount sufficient to substantially cover an entire surface of said permanent magnet, and a magnetic sensing element fixed to said case in opposing relation to said space, wherein said permanent magnet is moved to a lower position of the space by reason of its weight when said case is tilted so that magnetic sensed by said magnetic sensing element changes, thereby detecting that said case is tilted.
Claim 2
Dependent Claim
103 words
A magnetic tilt sensor comprising: a nonmagnetic case having a space therein, a permanent magnet housed to freely movable in said space, a magnetic fluid attracted to said permanent magnet, said magnetic fluid being of an amount sufficient to substantially cover an entire surface of said permanent magnet, and a magnetic sensing element fixed to said case in opposing relation to said space, wherein said permanent magnet is moved to a lower position of the space by reason of its weight when said case is tilted so that magnetic sensed by said magnetic sensing element changes, thereby detecting that said case is tilted.
Claim 3
Dependent Claim
18 words
A magnetic tilt sensor according to claim 1, wherein said magnetic sensing element is a Hall effect element.
Claim 4
Dependent Claim
26 words
A magnetic tilt sensor according to claim 1, wherein said magnetic fluid includes spherical magnetic metal powder particles mixed with an oil having a low viscosity.
Claim 5
Dependent Claim
51 words
A magnetic tilt sensor according to claim 3, wherein said spherical magnetic metal powder particles have a diameter in the range of 70 angstroms to 120 angstroms, said oil is a paraffin oil and said spherical magnetic metal powder particles are mixed with said paraffin oil in the ratio of 50:50.
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) | 1992-02-07 | 1992-08-08 | 1993-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-07 | 1996-08-08 | 1997-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-07 | 2000-08-08 | 2001-02-07 | $7700.00 | Window Closed / Lapsed |