Patent US5780561A successfully refreshed from Google Patents.
Patent US3268724A successfully refreshed from Google Patents.
US3268724A
Expired / Lapsed
US
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Safety device for trains
Assignee: Toshiba Corp
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Filing: 1962-12-11
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Granted: 1966-08-23
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Expires: 1982-12-11
Abstract
No abstract record available.
Inventors
- 👤 Hayashi Keiichi
- 👤 Watanabe Junichi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:09
CPC Classifications
B; B60; B60L; B60L3/00; B60L3/08; B60L2200/00; B60L2200/26
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
175 words
A SAFETY DEVICE FOR A TRAIN RUNNING ON A ROADBED, COMPRISING MEANS FOR OBTAINING A DIRECT CURRENT VOLTAGE INVERSELY PROPORTIONAL TO THE SPEED OF THE TRAIN, A REFERENCE VOLTAGE SOURCE, A COMPARING CIRCUIT ADAPTED TO COMPARE SAID DIRECT CURRENT VOLTAGE WITH SAID REFERENCE VOLTAGE, A PLURALITY OF SPEED SELECTING MEANS ACTUATED SELECTIVELY BY SPEED LIMITING SIGNALS TRANSMITTED TO SAID TRAIN FROM GROUND POSITIONS ALONG SAID ROADBED, EACH OF SAID SPEED SELECTING MEANS BEING ADAPTED TO CLOSE AN ELECTRIC CIRCUIT TO COMPARE A SELECTED PORTION OF SAID DIRECT CURRENT VOLTAGE WITH SAID REFERENCE VOLTAGE, MEANS INCLUDING TRANSISTOR MEANS, RECTIFYING MEANS AND AN ALTERNATING CURRENT SOURCE FOR SUPERPOSING A PULSE SIGNAL ON TO SAID DIRECT CURRENT VOLTAGE CORRESPONSING TO THE SPEED OF THE TRAIN SO AS TO CONVERT SAID DIRECT CURRENT VOLTAGE INTO A PULSATING VOLTAGE, A CONTROL DEVICE AND A SWITCHING CIRCUIT CONNECTED TO THE OUTPUT OF SAID SPEED SELECTING MEANS AND RESPONSIVE TO SAID PULSATING VOLTAGE WHEN WITHIN SELECTED VOLTAGE LIMITS AS DETERMINED BY SAID REFERENCE VOLTAGE TO SUPPLY CURRENT TO ENERGIZE SAID CONTROL DEVICE.
Claim 2
Dependent Claim
175 words
A SAFETY DEVICE FOR A TRAIN RUNNING ON A ROADBED, COMPRISING MEANS FOR OBTAINING A DIRECT CURRENT VOLTAGE INVERSELY PROPORTIONAL TO THE SPEED OF THE TRAIN, A REFERENCE VOLTAGE SOURCE, A COMPARING CIRCUIT ADAPTED TO COMPARE SAID DIRECT CURRENT VOLTAGE WITH SAID REFERENCE VOLTAGE, A PLURALITY OF SPEED SELECTING MEANS ACTUATED SELECTIVELY BY SPEED LIMITING SIGNALS TRANSMITTED TO SAID TRAIN FROM GROUND POSITIONS ALONG SAID ROADBED, EACH OF SAID SPEED SELECTING MEANS BEING ADAPTED TO CLOSE AN ELECTRIC CIRCUIT TO COMPARE A SELECTED PORTION OF SAID DIRECT CURRENT VOLTAGE WITH SAID REFERENCE VOLTAGE, MEANS INCLUDING TRANSISTOR MEANS, RECTIFYING MEANS AND AN ALTERNATING CURRENT SOURCE FOR SUPERPOSING A PULSE SIGNAL ON TO SAID DIRECT CURRENT VOLTAGE CORRESPONSING TO THE SPEED OF THE TRAIN SO AS TO CONVERT SAID DIRECT CURRENT VOLTAGE INTO A PULSATING VOLTAGE, A CONTROL DEVICE AND A SWITCHING CIRCUIT CONNECTED TO THE OUTPUT OF SAID SPEED SELECTING MEANS AND RESPONSIVE TO SAID PULSATING VOLTAGE WHEN WITHIN SELECTED VOLTAGE LIMITS AS DETERMINED BY SAID REFERENCE VOLTAGE TO SUPPLY CURRENT TO ENERGIZE SAID CONTROL DEVICE.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-08-22 | 1970-02-21 | 1970-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-08-22 | 1974-02-21 | 1974-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-08-22 | 1978-02-21 | 1978-08-23 | $7700.00 | Window Closed / Lapsed |