US3725904A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Encoder with a redundant optical system
Assignee: MOTION SYSTEMS COMPANY Inc
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Filing: 1971-07-23
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Granted: 1973-04-03
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Expires: 1991-07-23
Abstract
Abstract An absolute rotary encoder in which a redundant optical system is located at any one of several angular positions around the encoder disc relative to the original optical system. In the event of failure of a component in the original optical system, the redundant optical system is connected in place of the original optical system. In the embodiment where the redundant optical system is located at 90* away from the original optical system, signals from the redundant optical system are identical to signals from the original optical system for all but the most coarse and second most coarse encoder tracks. Signals from the photodetectors for the most coarse and second most coarse tracks of the redundant optical system are fed to compensating logic circuits which operate on these signals and yield positional output signals for the most and second most coarse tracks which are identical to positional output signals which would have been produced by the original optical system. In addition a simple logic circuit is provided which recognizes whether the primary or redundant system is connected and then performs the necessary signal switching.
Inventors
- 👤 D Breslow
- 👤 S Wingate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:43
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/14
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
174 words
In an absolute encoder having an encoder plate, and an original sensing system for sensing the position of said encoder plate relative to said original sensing system, said original sensing system being located at a first position relative to said encoder plate and producing a positional output signal indicative of the position of said encoder plate relative to said original sensing system, the improvement comprising: a. a redundant sensing system, located at a second position different from said first position along said encoder plate, for sensing the position of said encoder plate relative to said redundant sensing system and for producing a positional output signal indicative of the position of said encoder plate relative to said redundant sensing system; and b. electrical conversion means, coupled to said redundant sensing system, for converting signals from said redundant sensing system to produce a positional output signal for the encoder which is the equivalent of the positional output signal which would have been produced by the original sensing system for the same position of the encoder plate.
Claim 2
Dependent Claim
174 words
In an absolute encoder having an encoder plate, and an original sensing system for sensing the position of said encoder plate relative to said original sensing system, said original sensing system being located at a first position relative to said encoder plate and producing a positional output signal indicative of the position of said encoder plate relative to said original sensing system, the improvement comprising: a. a redundant sensing system, located at a second position different from said first position along said encoder plate, for sensing the position of said encoder plate relative to said redundant sensing system and for producing a positional output signal indicative of the position of said encoder plate relative to said redundant sensing system; and b. electrical conversion means, coupled to said redundant sensing system, for converting signals from said redundant sensing system to produce a positional output signal for the encoder which is the equivalent of the positional output signal which would have been produced by the original sensing system for the same position of the encoder plate.
Claim 3
Dependent Claim
22 words
Apparatus as set forth in claim 1 wherein said absolute encoder is a rotary encoder and said encoder plate is a disc.
Claim 4
Dependent Claim
25 words
Apparatus as set forth in claim 2 wherein said redundant sensing system is positioned 90* around said encoder disc relative to said original sensing system.
Claim 5
Dependent Claim
99 words
Apparatus as set forth in claim 1 wherein said encoder plate has a plurality of encoder tracks ranging from a most coarse encoder track to a most fine encoder track, and said original sensing system includes means for producing a plurality of signals, at least one for each encoder track, all of which form said positional output signal of said original sensing system, and further including: a. said redundant sensing systems having means for producing a plurality of signals, at least one for each encoder track, all of which form said positional output signal of said redundant sensing system.
Claim 6
Dependent Claim
145 words
Apparatus as set forth in claim 4 wherein said electrical conversion means includes a first logic circuit connected to the output circuit of said redundant sensing system for the second most coarse track for logically converting the signal for the second most coarse track from said redundant sensing system to produce a signal identical to the signal which would have been produced for the second most coarse track by the original sensing system, and a second logic circuit connected to the output circuits of said redundant sensing system for the most coarse and second most coarse tracks for logically converting the signal from said redundant sensing system for the most coarse encoder track to produce a signal for the most coarse encoder track which is identical to the signal which would have been produced for the most coarse encoder track by the original sensing system.
Claim 7
Dependent Claim
98 words
Apparatus as set forth in claim 4 wherein: a. said encoder is an optical encoder; b. said original sensing system is an optical system having a plurality of light sources to illuminate said encoder track, and a plurality of photodetectors, at least one for each track, for sensing whether each track is passing or blocking light; and c. said redundant sensing system is an optical system having a plurality of light sources to illuminate said encoder tracks, and a plurality of photodetectors, at least one for each track, for sensing whether each track is passing or blocking light.
Claim 8
Dependent Claim
22 words
Apparatus as set forth in claim 6 wherein said absolute encoder is a rotary encoder and said eNcoder plate is a disc.
Claim 9
Dependent Claim
25 words
Apparatus as set forth in claim 7 wherein said redundant sensing system is positioned 90* around said encoder disc relative to said original sensing system.
Claim 10
Dependent Claim
145 words
Apparatus as set forth in claim 8 wherein said electrical conversion means includes a first logic circuit connected to the output circuit of said redundant sensing system for the second most coarse track for logically converting the signal for the second most coarse track from said redundant sensing system to produce a signal identical to the signal which would have been produced for the second most coarse track by the original sensing system, and a second logic circuit connected to the output circuits of said redundant sensing system for the most coarse and second most coarse tracks for logically converting the signal from said redundant sensing system for the most coarse encoder track to produce a signal for the most coarse encoder track which is identical to the signal which would have been produced for the most coarse encoder track by the original sensing system.
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) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |