US4534171A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic dual-circuit tandem main brake cylinder
Assignee: Robert Bosch GmbH
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Filing: 1983-11-04
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Granted: 1985-08-13
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Expires: 2003-11-04
Abstract
Abstract A hydraulic dual-circuit tandem main brake cylinder which includes at least one closed brake circuit (I) having a brake piston. This brake piston is actuated by means of the pressure fed into a pressure chamber by means of a brake control valve with a travel simulator spring. Adjoining this pressure chamber is also an auxiliary piston device, which comprises an auxiliary piston and a tappet passing therethrough and connected indirectly with the brake pedal. A highly progressive spring is fastened between the auxiliary piston and the tappet; this spring predominantly determines the pedal characteristic.
Inventors
- 👤 Heinz Leiber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:06
CPC Classifications
B; B60; B60T; B60T13/00; B60T13/10; B60T13/12; B60T13/14; B60T13/142; B60T13/143; B60T7/00; B60T7/02; B60T7/04; B60T7/042
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
186 words
A hydraulic dual-circuit brake system including first and second main brake cylinders in tandem, comprising at least one brake piston for a closed brake circuit, a brake fluid control valve which is actuatable via a brake pedal-actuated body part in combination with a travel simulator spring which acts upon said body part and said control valve, said control valve controls a control pressure fluid flow from a control pressure source into a pressure chamber which is adjoined by a control face of at least one brake piston, and an auxiliary piston adjoining the pressure chamber, said auxiliary piston including a tappet which passes through and is displaceably supported in the auxiliary piston and which is actuated by movement of said pedal and said body part, a progressive spring fastened between one side of the auxiliary piston and said brake pedal-actuated body part remote from the pressure chamber and coaxial with the tappet passing through said auxiliary piston, characterized in that said progressive spring is directed against said auxiliary piston and has a highly progressive spring characteristic and as a result effects a highly progressive pedal characteristic.
Claim 2
Dependent Claim
186 words
A hydraulic dual-circuit brake system including first and second main brake cylinders in tandem, comprising at least one brake piston for a closed brake circuit, a brake fluid control valve which is actuatable via a brake pedal-actuated body part in combination with a travel simulator spring which acts upon said body part and said control valve, said control valve controls a control pressure fluid flow from a control pressure source into a pressure chamber which is adjoined by a control face of at least one brake piston, and an auxiliary piston adjoining the pressure chamber, said auxiliary piston including a tappet which passes through and is displaceably supported in the auxiliary piston and which is actuated by movement of said pedal and said body part, a progressive spring fastened between one side of the auxiliary piston and said brake pedal-actuated body part remote from the pressure chamber and coaxial with the tappet passing through said auxiliary piston, characterized in that said progressive spring is directed against said auxiliary piston and has a highly progressive spring characteristic and as a result effects a highly progressive pedal characteristic.
Claim 3
Dependent Claim
44 words
A tandem main brake cylinder as defined by claim 1, in which two tandem-disposed brake pistons are used to supply two closed brake circuits, and a pressure in the pressure chamber directly serves solely as a control pressure for one of said brake pistons.
Claim 4
Dependent Claim
24 words
A tandem main brake cylinder as defined by claim 1, characterized in that an open brake circuit II is connected to the pressure chamber.
Claim 5
Dependent Claim
23 words
A tandem main brake cylinder as defined by claim 1, characterized in that said first and second main brake cylinders have different diameters.
Claim 6
Dependent Claim
23 words
A tandem main brake cylinder as defined by claim 2, characterized in that said first and second main brake cylinders have different diameters.
Claim 7
Dependent Claim
23 words
A tandem main brake cylinder as defined by claim 3, characterized in that said first and second main brake cylinders have different diameters.
Claim 8
Dependent Claim
47 words
A tandem main brake cylinder as defined by claim 1, characterized in that said travel simulator spring and said progressive spring are adapted to one another by said brake pedal-actuated body part in such a manner that they have a constant force ratio in terms of travel.
Claim 9
Dependent Claim
47 words
A tandem main brake cylinder as defined by claim 2, characterized in that said travel simulator spring and said progressive spring are adapted to one another by said brake pedal-actuated body part in such a manner that they have a constant force ratio in terms of travel.
Claim 10
Dependent Claim
47 words
A tandem main brake cylinder as defined by claim 3, characterized in that said travel simulator spring and said progressive spring are adapted to one another by said brake pedal-actuated body part in such a manner that they have a constant force ratio in terms of travel.
Claim 11
Dependent Claim
47 words
A tandem main brake cylinder as defined by claim 4, characterized in that said travel simulator spring and said progressive spring are adapted to one another by said brake pedal-actuated body part in such a manner that they have a constant force ratio in terms of travel.
Claim 12
Dependent Claim
47 words
A tandem main brake cylinder as defined by claim 5, characterized in that said travel simulator spring and said progressive spring are adapted to one another by said brake pedal-actuated body part in such a manner that they have a constant force ratio in terms of travel.
Claim 13
Dependent Claim
47 words
A tandem main brake cylinder as defined by claim 6, characterized in that said travel simulator spring and said progressive spring are adapted to one another by said brake pedal-actuated body part in such a manner that they have a constant force ratio in terms of travel.
References Cited (Backward Citations)
US3334548A
Cited
US3751025A
Cited
US4137718A
Cited
US4218958A
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US4326379A
Cited
US4366745A
Cited
EP0082367A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-08-12 | 1989-02-11 | 1989-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-12 | 1993-02-11 | 1993-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-12 | 1997-02-11 | 1997-08-13 | $7700.00 | Window Closed / Lapsed |