US3576568A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Warning device for a braking split system
Assignee: DBA SA
•
Filing: 1968-03-07
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Granted: 1971-04-27
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Expires: 1988-03-07
Abstract
Abstract A combination stop warning switch and brake system failure indicator switch is disclosed for use on automotive vehicles having split braking systems. When the brakes function normally, the switch actuates the vehicle''s stop warning system when the vehicle''s brakes are applied. However, if a malfunction causes the pressure in one of the brake systems to exceed the pressure in the other system by more than a predetermined amount during a brake application, the switch actuates both the stop warning system and a warning device in the vehicle''s operator''s compartment.
Inventors
- 👤 Rene Thirion
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:59
CPC Classifications
B; B60; B60T; B60T17/00; B60T17/18; B60T17/22; B60T17/226; H; H01; H01H; H01H35/00; H01H35/24; H01H35/38
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
344 words
A vehicle hydraulic braking system having first and second hydraulic systems, a stop warning system, and a warning system for indicating a pressure differential between said first and second hydraulic system, said breaking system including: a housing defining a bore therewithin; first and second piston means slidable in said bore; said first and second piston means defining first and second fluid chambers between one end of the first or second piston means and a corresponding end of the bore; said first and second chambers being in fluid communication with said first and second hydraulic systems respectively; third piston means slidably disposed in said bore between said first and second piston means; first and second relatively movable switch contacts operatively connected to said stop warning system for actuating the latter; one of said first or second switch contacts projecting into said bore between one of said first or second piston means and said third piston means; the other of said first or second switch contacts projecting inTo said bore between the other of said first or second piston means and said third piston means; and a third switch contact operatively connected to said pressure differential warning system and projecting into said bore; said first and second piston means forcing each of said first and second switch contacts into a position establishing an electrically conductive path between the first and second contacts through said third piston means when the vehicle''s brakes are applied and the fluid pressure levels in said first and second chambers are substantially equal to actuate the vehicle''s stop warning system; one of said first or second piston means driving a corresponding one of said first or second switch contacts into electrically conductive engagement with said third piston means and thereafter shifting said third piston means into electrically conductive engagement with said third switch contact to actuate the vehicle''s pressure differential warning system when the vehicle''s brakes are applied and the fluid pressure level in the corresponding one of said chambers exceeds the pressure level in the other chamber by a predetermined amount.
Claim 2
Dependent Claim
344 words
A vehicle hydraulic braking system having first and second hydraulic systems, a stop warning system, and a warning system for indicating a pressure differential between said first and second hydraulic system, said breaking system including: a housing defining a bore therewithin; first and second piston means slidable in said bore; said first and second piston means defining first and second fluid chambers between one end of the first or second piston means and a corresponding end of the bore; said first and second chambers being in fluid communication with said first and second hydraulic systems respectively; third piston means slidably disposed in said bore between said first and second piston means; first and second relatively movable switch contacts operatively connected to said stop warning system for actuating the latter; one of said first or second switch contacts projecting into said bore between one of said first or second piston means and said third piston means; the other of said first or second switch contacts projecting inTo said bore between the other of said first or second piston means and said third piston means; and a third switch contact operatively connected to said pressure differential warning system and projecting into said bore; said first and second piston means forcing each of said first and second switch contacts into a position establishing an electrically conductive path between the first and second contacts through said third piston means when the vehicle''s brakes are applied and the fluid pressure levels in said first and second chambers are substantially equal to actuate the vehicle''s stop warning system; one of said first or second piston means driving a corresponding one of said first or second switch contacts into electrically conductive engagement with said third piston means and thereafter shifting said third piston means into electrically conductive engagement with said third switch contact to actuate the vehicle''s pressure differential warning system when the vehicle''s brakes are applied and the fluid pressure level in the corresponding one of said chambers exceeds the pressure level in the other chamber by a predetermined amount.
Claim 3
Dependent Claim
128 words
The invention of claim 1; and electrically insulative resilient means carried by said third piston means yieldably biasing said first and second switch contacts away from the third piston means; said first and second piston means forcing a corresponding one of said first or second contacts against the piston means upon actuation of the vehicle''s brakes and substantially equal fluid pressure levels in said chambers; one of said first or second piston means forcing a corresponding one of said first or second switch contacts against said third piston means and thereafter forcing the latter against said third contact when the vehicle''s brakes are actuated and the fluid pressure level in the corresponding one of said chambers exceeds the pressure level in the other chamber by a predetermined amount.
Claim 4
Dependent Claim
26 words
The invention of claim 1: said third piston means having a recess provided in the outer surface thereof; said third switch contact projecting into said recess.
References Cited (Backward Citations)
US1555074A
Cited
US2118125A
Cited
US2450961A
Cited
US3011595A
Cited
US2857584A
Cited
US3439322A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-26 | 1974-10-26 | 1975-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-26 | 1978-10-26 | 1979-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-26 | 1982-10-26 | 1983-04-27 | $7700.00 | Window Closed / Lapsed |