Patent US3902158A successfully refreshed from Google Patents.
US3902158A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical device for detecting or indicating vehicle brake lining wear
Assignee: SAB Brake Regulator Co Ltd
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Filing: 1974-04-03
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Granted: 1975-08-26
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Expires: 1994-04-03
Abstract
Abstract An electric brake lining wear detector comprises a wire loop ruptured by the brake drum as the lining wears past a threshold value and a corresponding detection circuit for developing an alarm signal when the loop is ruptured or the circuit is otherwise faulted such as by shorting to ground. A normally energized actuating relay has one terminal connected to the ''''earth'''' battery terminal and the detector switch in the brake lining is coupled in series circuit so that a damaged or earthed detector switch will provide a warning.
Inventors
- 👤 Nils Goran Dahlkvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:28
CPC Classifications
F; F16; F16D; F16D66/00; F16D66/02; F16D66/021; F16D66/022; F16D66/026
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
193 words
An electrical device for indicating the brake lining wear in a vehicle having brake linings and an electrically earthed conductive circuit comprising in combination, a voltage source with one pole connected to said earthed circuit, two terminal electrically operable relay control means having a control circuit, and warning switch means operated by said control means responsive to different electrical conditions in said control circuit to energize said control means in one position as holding meanS, detection switch means located in said brake lining comprising a normally closed conductive circuit which becomes ruptured and opened in response to brake lining wear exceeding a predetermined limit, a circuit connecting said voltage source temporarily to operate said control means in a first holding condition through said detection switch means with one control means terminal earthed and said detection switch means connected serially with the other terminal to said unearthed voltage source pole, and a warning device operated by said control means through said warning switch means when said detection switch means is opened to release said holding means, whereby any earthing of said detection switch means will cause said control device to operate said warning device.
Claim 2
Dependent Claim
193 words
An electrical device for indicating the brake lining wear in a vehicle having brake linings and an electrically earthed conductive circuit comprising in combination, a voltage source with one pole connected to said earthed circuit, two terminal electrically operable relay control means having a control circuit, and warning switch means operated by said control means responsive to different electrical conditions in said control circuit to energize said control means in one position as holding meanS, detection switch means located in said brake lining comprising a normally closed conductive circuit which becomes ruptured and opened in response to brake lining wear exceeding a predetermined limit, a circuit connecting said voltage source temporarily to operate said control means in a first holding condition through said detection switch means with one control means terminal earthed and said detection switch means connected serially with the other terminal to said unearthed voltage source pole, and a warning device operated by said control means through said warning switch means when said detection switch means is opened to release said holding means, whereby any earthing of said detection switch means will cause said control device to operate said warning device.
Claim 3
Dependent Claim
45 words
A device as defined in claim 1 wherein the vehicle has an electrical starting system including automatic reset means for said control means comprising a circuit with a diode connected from the starting system to supply voltage to said unearthed terminal of said control means.
Claim 4
Dependent Claim
67 words
A device as defined in claim 1, including a further electrically operable relay control means connected between the voltage source and the detection switch, and a further warning device operable by said further control means, whereby one said control means gives warning of temporary brake wear elements as said detection switch becomes earthed before rupture, and the other control means gives warning of an open detection switch.
Claim 5
Dependent Claim
44 words
A device as defined in claim 1 wherein the vehicle has an electrical starting system including two separate automatic reset means each comprising a circuit with a diode connected from the starting system to supply voltage to a respective one of said control means.
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) | 1978-08-25 | 1979-02-24 | 1979-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-25 | 1983-02-24 | 1983-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-25 | 1987-02-24 | 1987-08-26 | $7700.00 | Window Closed / Lapsed |