Patent US3728561A successfully refreshed from Google Patents.
Patent US3855797A successfully refreshed from Google Patents.
US3855797A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic master cylinder
Assignee: DEA SA
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Filing: 1973-12-06
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Granted: 1974-12-24
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Expires: 1993-12-06
Abstract
Abstract The master-cylinder comprises a body defining a cavity therewithin, a bore opening into the cavity, a floating piston slidable in the bore to define a first chamber and a second chamber including the cavity, a spool valve for controlling fluid pressure in the second chamber upon actuation of a control rod, a lever mechanism interconnecting the rod, the piston and the valve for opening the latter, and a cut-off valve located in the first chamber for controlling the fluid flowing out from the first chamber. The cut-off valve includes a valve seat surrounding the outlet port of the first chamber and a valve member secured to a plunger slidable in an inner bore located in the floating piston, the inner bore opening at one end into said first chamber and at the other end into a compartment communicating with a low pressure reservoir and a spring biasing the plunger in abutment with a stop fixed relative to the floating piston.
Inventors
- 👤 G Papiau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:59
CPC Classifications
B; B60; B60T; B60T13/00; B60T13/10; B60T13/12; B60T13/14; B60T13/142; B60T13/145; B60T13/146
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
184 words
In a hydraulic brake actuating device: a housing defining a bore therewithin; a piston slidably mounted in said bore and cooperating with opposite ends of the latter to define a pair of pressure chambers; an outlet communicating with one of said chambers valve means shiftable from a condition venting the other chamber to a fluid reservoir to a position communicating said other chamber with a source of fluid pressure to thereby shift said piston to develop fluid pressure in said one chamber; and a pressure differential responsive plunger having a pair of opposed faces slidably mounted on said piston, and resilient means yieldably urging said plunger to a predetermined position with respect to the piston, one of said faces being exposed to the fluid pressure level in said one chamber, the other face of said plunger being communicated with the fluid pressure level in said resevoir; and cut-off valve means carried by said plunger for cooperation with said outlet to terminate communication therethrough when the fluid pressure level in said one chamber drops below a predetermined level for a given movement of the piston.
Claim 2
Dependent Claim
184 words
In a hydraulic brake actuating device: a housing defining a bore therewithin; a piston slidably mounted in said bore and cooperating with opposite ends of the latter to define a pair of pressure chambers; an outlet communicating with one of said chambers valve means shiftable from a condition venting the other chamber to a fluid reservoir to a position communicating said other chamber with a source of fluid pressure to thereby shift said piston to develop fluid pressure in said one chamber; and a pressure differential responsive plunger having a pair of opposed faces slidably mounted on said piston, and resilient means yieldably urging said plunger to a predetermined position with respect to the piston, one of said faces being exposed to the fluid pressure level in said one chamber, the other face of said plunger being communicated with the fluid pressure level in said resevoir; and cut-off valve means carried by said plunger for cooperation with said outlet to terminate communication therethrough when the fluid pressure level in said one chamber drops below a predetermined level for a given movement of the piston.
Claim 3
Dependent Claim
43 words
The invention of claim 1: said piston defining a cavity opening into said one chamber, said plunger being slidably mounted in said cavity and cooperating with the end of the latter to define a fluid-receiving compartment, said compartment being communicated to said reservoir.
Claim 4
Dependent Claim
44 words
The invention of claim 2; and a valve seat circumscribing said outlet, the cross-sectional area of said valve seat being substantially equal to the cross-sectional area of said plunger; said cut-off valve means sealingly engaging said valve seat to terminate communication through said outlet.
Claim 5
Dependent Claim
36 words
The invention of claim 3; and means On said piston and on said plunger defining stop means for establishing the rest position of said plunger; said resilient means yieldably urging said plunger toward said rest position.
Claim 6
Dependent Claim
26 words
The invention of claim 4: said means defining said stop means being a shoulder carried by said piston cooperating with a corresponding shoulder on the plunger.
References Cited (Backward Citations)
US2410269A
Cited
FR1105351A
Cited
US3427807A
Cited
US3216194A
Cited
US3610101A
Cited
US3698190A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |