US3874778A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotary mirror scanner
Assignee: Hitachi Ltd
•
Filing: 1973-12-26
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Granted: 1975-04-01
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Expires: 1993-12-26
Abstract
Abstract A rotary mirror scanner for deflecting a light beam by means of a rotary mirror driven mechanically. The rotary mirror is mounted on a rotary shaft supported by dynamic air or gas journal bearings and a repulsion type magnetic thrust bearing housed in a casing. By this arrangement, the need to use a compressed air or gas source which is essential to rotary mirror scanners of the prior art is eliminated and the rotary mirror scanner can rotate very quietly at very high speeds.
Inventors
- 👤 Shigeo Kato
- 👤 Hitoshi Masuko
- 👤 Yukio Kameyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:25
CPC Classifications
F; F16; F16C; F16C32/00; F16C32/04; F16C32/0406; F16C32/0408; F16C32/0423; F16C32/0427; F16C17/00; F16C17/02; F16C17/03; F16C32/0402; F16C32/044; F16C32/0444; F16C39/00; F16C39/06; F16C39/063; G; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/12; G02B26/121; G02B7/00; G02B7/18; F16C2370/00; F16C2370/20; F16C2370/22
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
184 words
A rotary mirror scanner comprising a rotary shaft having affixed to one portion thereof a rotary mirror comprising at least one mirror surface capable of deflecting in a predetermined direction a light beam incident thereon from one direction, a plurality of dynamic gas journal bearings each being disposed in a position for supporting said rotary shaft and adapted dynamically to increase the pressure of air surrounding the rotary shaft as the number of revolution of the rotary shaft increases so as to support the rotary shaft by radially exerting thereon a centripetal force, a repulsion type thrust bearing disposed in a position for axially supporting said rotary shaft and adapted to support the same by causing the same to float axially by the magnetic force of repulsion, and a drive disposed in the vicinity of said rotary shaft in a position other than the positions in which said rotary mirror, said dynamic gas journal bearings and said repulsion type magnetic thrust bearing are disposed so as to rotate the rotary shaft by the revolving magnetic field produced in the vicinity of the magnetic field.
Claim 2
Dependent Claim
184 words
A rotary mirror scanner comprising a rotary shaft having affixed to one portion thereof a rotary mirror comprising at least one mirror surface capable of deflecting in a predetermined direction a light beam incident thereon from one direction, a plurality of dynamic gas journal bearings each being disposed in a position for supporting said rotary shaft and adapted dynamically to increase the pressure of air surrounding the rotary shaft as the number of revolution of the rotary shaft increases so as to support the rotary shaft by radially exerting thereon a centripetal force, a repulsion type thrust bearing disposed in a position for axially supporting said rotary shaft and adapted to support the same by causing the same to float axially by the magnetic force of repulsion, and a drive disposed in the vicinity of said rotary shaft in a position other than the positions in which said rotary mirror, said dynamic gas journal bearings and said repulsion type magnetic thrust bearing are disposed so as to rotate the rotary shaft by the revolving magnetic field produced in the vicinity of the magnetic field.
Claim 3
Dependent Claim
77 words
A rotary mirror scanner according to claim 1 wherein said plurality of dynamic gas journal bearings are of the tilting pad type and comprises a plurality of pads each being in the form of a circularly arcuate shape and disposed in spaced juxtaposed relationship to the rotary shaft for supporting the same, and a plurality of pivot arms each supporting one of said pads for pivotal movement about a spherical bearing member formed in each pivot arm.
Claim 4
Dependent Claim
90 words
A rotary mirror scanner according to claim 1 wherein said repulsion type magnetic bearing comprises rotary magnet affixed to one portion of said rotary shaft and rotating therewith, and stationary magnet disposed in spaced juxtaposed relationship to said rotary magnet and magnetized oppositely thereto for causing the rotary shaft to float axially, said rotary magnet and said stationary magnet being of a shape such that no change is caused to occur in the magnetic flux between the rotary magnet and the stationary magnet by the rotation of the rotary magnet.
Claim 5
Dependent Claim
34 words
A rotary mirror scanner according to claim 3 Further comprising a damper means adapted to hold said stationary magnet of said repulsion type thrust bearing and absorb the axial vibration of the rotary shaft.
References Cited (Backward Citations)
US3166997A
Cited
US3511149A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |