Patent US2448797A successfully refreshed from Google Patents.
US3626366A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-latching differential pressure switch
Assignee: Bendix Corp
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Filing: 1969-09-02
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Granted: 1971-12-07
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Expires: 1989-09-02
Abstract
Abstract A switch responsive to differential pressure between first and second hydraulic brake systems three pistons arranged in endabutting relationship in the bore of a housing. The outermost ends of the two outer pistons and the corresponding ends of the housing define a pair of fluid chambers, each of which is in communication with one of the two hydraulic systems. The inner piston actuates a warning device when it is shifted in the bore by one of the two outer pistons due to a pressure differential created in the two chambers resulting from a defective system. When the defective system is repaired, the first brake application recenters the three pistons, thereby deactivating the warning device.
Inventors
- 👤 George M Tam
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:32
CPC Classifications
B; B60; B60T; B60T17/00; B60T17/18; B60T17/22; B60T17/226
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
228 words
In a switch responsive to a pressure differential between first and second hydraulic systems: a housing defining a bore therewithin; piston means slidably mounted in said bore and defining first and second chambers between opposite ends of the piston means and corresponding ends of the bore; said first and second chambers being in fluid communication with said first and second hydraulic systems respectively; said piston means including an inner section and a pair of outer sections, one end of each of said outer sections normally engaging opposite ends of said inner section, said inner section and the outer sections shifting as a unit from a first position to a second position in response to a pressure differential between said first and second chambers due to loss of fluid pressure in one of said hydraulic systems, said inner section and one of said outer sections remaining in said second position after fluid pressure in the other hydraulic system is released; switch means responsive to movement of said inner section to said second position for actuating a warning device; and resilient means yieldably urging the other outer section toward its first position after fluid pressure in the other hydraulic system is released; said inner section and said one outer section returning to their corresponding first positions after substantially equal pressures are again established in said first and second hydraulic systems.
Claim 2
Dependent Claim
228 words
In a switch responsive to a pressure differential between first and second hydraulic systems: a housing defining a bore therewithin; piston means slidably mounted in said bore and defining first and second chambers between opposite ends of the piston means and corresponding ends of the bore; said first and second chambers being in fluid communication with said first and second hydraulic systems respectively; said piston means including an inner section and a pair of outer sections, one end of each of said outer sections normally engaging opposite ends of said inner section, said inner section and the outer sections shifting as a unit from a first position to a second position in response to a pressure differential between said first and second chambers due to loss of fluid pressure in one of said hydraulic systems, said inner section and one of said outer sections remaining in said second position after fluid pressure in the other hydraulic system is released; switch means responsive to movement of said inner section to said second position for actuating a warning device; and resilient means yieldably urging the other outer section toward its first position after fluid pressure in the other hydraulic system is released; said inner section and said one outer section returning to their corresponding first positions after substantially equal pressures are again established in said first and second hydraulic systems.
Claim 3
Dependent Claim
81 words
The invention of claim 1; and stop means slidable in said bore and operably connected to each of said outer sections and to said resilient means, said stop means permitting substantially uninhibited movement of each of said outer sections toward its corresponding adjacent end of the bore, said stop means cooperating with said resilient means to urge each of said outer sections toward their corresponding first position upon movement of the latter away from their corresponding adjacent ends of the bore.
Claim 4
Dependent Claim
67 words
The invention of claim 2 said bore being stepped to present larger diameter portions adjacent the ends of the bore and A smaller diameter portion therebetween; said stop means including a pair of sleeves; each of said sleeves being reciprocable in a corresponding larger diameter portion of the bore; each of said outer sections being slidably received by one of said sleeves and said smaller diameter portion.
Claim 5
Dependent Claim
37 words
The invention of claim 3: there being oppositely facing shoulders between each of said larger diameter portions and said smaller diameter portion; said resilient means being springs interposed between each of said shoulders and a corresponding sleeve.
Claim 6
Dependent Claim
41 words
The invention of claim 4: each of said sleeves having a radially inwardly extending portion adapted to engage an outwardly projecting shoulder on the corresponding outer section upon movement of the latter away from its corresponding adjacent end of the bore.
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) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |