Patent US3869695A successfully refreshed from Google Patents.
US3869695A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Worn brake lining alarm circuit
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1973-07-20
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Granted: 1975-03-04
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Expires: 1993-07-20
Abstract
Abstract A negative resistance diode and an alarm device are connected in a series circuit with a battery whose terminal potential is higher than the threshold switching voltage of the diode. A worn brake lining detector circuit is connected in shunt with the series circuit. Normally, the shunt circuit draws current from the battery so that the voltage applied across the diode is below its switching voltage but above its holding voltage, and the alarm is not actuated. If even a momentary interruption of the shunt circuit occurs, the full battery potential is applied to the diode, thereby switching the diode into a conducting state to actuate the alarm. Even if the shunt circuit is subsequently closed by electrical contact with the rotating brake disc, the holding current through the diode is maintained, so that the diode remains conducting and the alarm remains actuated.
Inventors
- 👤 Yasuo Kita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:15
CPC Classifications
F; F16; F16D; F16D66/00; F16D66/02; F16D66/021; F16D66/022
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
175 words
In combination with a worn brake-lining detector circuit of the type which is electrically interrupted when the lining wears down to a predetermined working limit, an improved alarm circuit for indicating the interruption comprising: a. a D.C. power source, b. voltage divider means connected to said power source, c. a normally non-conducting two-terminal negative resistance diode coupled to said voltage divider means, d. means connecting said detector circuit in shunt with said diode; whereby when said shunt-connected detector circuit is normally uninterrupted, the divided voltage applied to said diode by said voltage divider means is less than the threshold switching voltage, but greater than the holding voltage, of said diode; and e. said D.C. power source having a terminal potential greater than or equal to the threshold switching voltage of said diode so that, when said detector circuit is interrupted even only momentarily, said terminal voltage is applied to said diode to render said diode conducting as an indication of the interruption, said diode remaining continuously conducting even if said detector circuit is subsequently closed.
Claim 2
Dependent Claim
175 words
In combination with a worn brake-lining detector circuit of the type which is electrically interrupted when the lining wears down to a predetermined working limit, an improved alarm circuit for indicating the interruption comprising: a. a D.C. power source, b. voltage divider means connected to said power source, c. a normally non-conducting two-terminal negative resistance diode coupled to said voltage divider means, d. means connecting said detector circuit in shunt with said diode; whereby when said shunt-connected detector circuit is normally uninterrupted, the divided voltage applied to said diode by said voltage divider means is less than the threshold switching voltage, but greater than the holding voltage, of said diode; and e. said D.C. power source having a terminal potential greater than or equal to the threshold switching voltage of said diode so that, when said detector circuit is interrupted even only momentarily, said terminal voltage is applied to said diode to render said diode conducting as an indication of the interruption, said diode remaining continuously conducting even if said detector circuit is subsequently closed.
Claim 3
Dependent Claim
41 words
The improved alarm circuit as defined in claim 1, further comprising a current-actuated alarm means connected in series with said diode, and wherein said detector circuit is connected in shunt with the series combination of said diode and said alarm means.
Claim 4
Dependent Claim
24 words
The improved alarm circuit as defined in claim 1, wherein said diode is a light-emitting diode which emits light when said diode becomes conducting.
Claim 5
Dependent Claim
76 words
The improved alarm circuit as defined in claim 1, wherein said voltage divider comprises a resistor and the internal resistance of an electrical alarm means connected in series between said detector circuit and one terminal of said power source; and further comprising means connecting said diode between the other terminal of said power source and the function of said resistor and said alarm means, whereby said alarm means is current-activated only when said diode is conducting.
References Cited (Backward Citations)
US3660815A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-03 | 1978-09-02 | 1979-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-03 | 1982-09-02 | 1983-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-03 | 1986-09-02 | 1987-03-04 | $7700.00 | Window Closed / Lapsed |