Patent US3800539A successfully refreshed from Google Patents.
US3800539A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tandem master cylinder
Assignee: DBA SA
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Filing: 1973-03-08
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Granted: 1974-04-02
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Expires: 1993-03-08
Abstract
Abstract A tandem master cylinder comprising a housing with a bore therein in which are slidably mounted in telescopic relationship a control piston and a floating piston of fingerstall shape. Tilting valves are also provided for permitting pressure chamber of the master cylinder to be refilled. Each tilting valve has a stem projecting into the path of one piston to be independently and directly operated thereby.
Inventors
- 👤 Marchand A Le
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:58
CPC Classifications
B; B60; B60T; B60T11/00; B60T11/10; B60T11/16; B60T11/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
200 words
A tandem master cylinder comprising a housing with a bore therein, an assembLy comprising two pistons telescopic relative to one another being slidably mounted in said bore, so as to define two variable-volume chambers, said assembly comprising a floating piston of fingerstall shape slidably mounted in the bore in the housing and cooperating with the inside wall of said bore by way of an annular centering boss and by way of an annular sealing boss, and a stepped actuating piston having a centering head slidably mounted in the inner bore in the floating piston and a sealing boss slidably mounted in the bore in the housing, resilient means being provided to urge each piston into an idle position which is fixed relative to the housing, each chamber communicates with a hydraulic reservoir by way of a valve having a tiltable closure member and each having a valve stem which projects into the path of said piston assembly, the valve stems cooperating by direct abutment respectively with the centering boss on the floating piston and a shoulder on the centering head, so as to permit independent replenishment of both variable-volume chambers when the two pistons are urged into their idle positions.
Claim 2
Dependent Claim
200 words
A tandem master cylinder comprising a housing with a bore therein, an assembLy comprising two pistons telescopic relative to one another being slidably mounted in said bore, so as to define two variable-volume chambers, said assembly comprising a floating piston of fingerstall shape slidably mounted in the bore in the housing and cooperating with the inside wall of said bore by way of an annular centering boss and by way of an annular sealing boss, and a stepped actuating piston having a centering head slidably mounted in the inner bore in the floating piston and a sealing boss slidably mounted in the bore in the housing, resilient means being provided to urge each piston into an idle position which is fixed relative to the housing, each chamber communicates with a hydraulic reservoir by way of a valve having a tiltable closure member and each having a valve stem which projects into the path of said piston assembly, the valve stems cooperating by direct abutment respectively with the centering boss on the floating piston and a shoulder on the centering head, so as to permit independent replenishment of both variable-volume chambers when the two pistons are urged into their idle positions.
Claim 3
Dependent Claim
75 words
A master cylinder as claimed in claim 1, further including: stop means having a radial projection which is fixed to the housing and whose inner end projects into the bore in the housing substantially opposite the orifice of that valve controlling replenishing of the variable-volume chamber situated between the two pistons, so as to cooperate by direct abutment with the sealing boss on the floating piston and with the centering head of the actuating piston.
Claim 4
Dependent Claim
83 words
A master cylinder as claimed in claim 2, wherein said projection includes: a screw mounted in a fluid-tight manner in an opening provided in the housing, the inner end of the screw comprising two coaxial cylindrical portions of larger and smaller diameters on which the floating piston and the actuating piston respectively come to bear, so that the sealing boss of the floating piston cannot interfere with the shoulder on the centering head during operation of the valve associated with the actuating piston.
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) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |