Patent US4489555A successfully refreshed from Google Patents.
US4489555A
Expired / Lapsed
US
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Hydraulic dual-circuit brake booster
Assignee: Robert Bosch GmbH
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Filing: 1983-10-03
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Granted: 1984-12-25
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Expires: 2003-10-03
Abstract
Abstract A hydraulic dual-circuit brake booster in which two brake circuits are closed brake circuits. A dual-circuit tandem main cylinder is used in combination with a pedal push rod supported in a displaceable piston and exposed to the brake pressure directed into the system by the control valve. The pedal push rod and the tandem main brake cylinder are disposed coaxially and the brake booster is particularly suitable for use with anti-skid brake systems.
Inventors
- 👤 Heinz Leiber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:22
CPC Classifications
B; B60; B60T; B60T13/00; B60T13/10; B60T13/12; B60T13/14; B60T13/142; B60T13/145; B60T8/00; B60T8/32; B60T8/34; B60T8/44; B60T8/441
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
137 words
A hydraulic dual-circuit brake booster for vehicle brake systems, which includes a hydraulic main cylinder actuated via a pedal-moved push rod in which said hydraulic main cylinder is disposed coaxially relative to said push rod, a control valve switched by the pedal for directing pressure of a pressure source into the main cylinder, said control valve including a travel limiting means, said hydraulic main cylinder being a dual-circuit tandem main cylinder operable to control two closed brake circuits, said pedal push rod being supported in and movable relative to a displaceable piston including an inner effective surface which is subjected to pressure directed into the system by the control valve and said pedal push rod and the tandem main cylinder are coaxially disposed with said pedal push rod extending from one end of said tandem main cylinder.
Claim 2
Dependent Claim
137 words
A hydraulic dual-circuit brake booster for vehicle brake systems, which includes a hydraulic main cylinder actuated via a pedal-moved push rod in which said hydraulic main cylinder is disposed coaxially relative to said push rod, a control valve switched by the pedal for directing pressure of a pressure source into the main cylinder, said control valve including a travel limiting means, said hydraulic main cylinder being a dual-circuit tandem main cylinder operable to control two closed brake circuits, said pedal push rod being supported in and movable relative to a displaceable piston including an inner effective surface which is subjected to pressure directed into the system by the control valve and said pedal push rod and the tandem main cylinder are coaxially disposed with said pedal push rod extending from one end of said tandem main cylinder.
Claim 3
Dependent Claim
30 words
A brake booster as defined by claim 1, in which the control valve is located outside and parallel with the axis of the pedal push rod and tandem main cylinder.
Claim 4
Dependent Claim
26 words
A brake booster as defined by claim 1, in which the control valve is located coaxially with the pedal push rod and the tandem main cylinder.
Claim 5
Dependent Claim
23 words
A brake booster as defined by claim 1, which comprises at least one position monitoring switch operable by acutation of said foot pedal.
Claim 6
Dependent Claim
23 words
A brake booster as defined by claim 2, which comprises at least one position monitoring switch operable by actuation of said foot pedal.
Claim 7
Dependent Claim
23 words
A brake booster as defined by claim 3, which comprises at least one position monitoring switch operable by actuation of said foot pedal.
Claim 8
Dependent Claim
29 words
A brake booster as defined by claim 1, which comprises a refill container on the tandem main cylinder in which said refill container is embodied as a three-chamber container.
Claim 9
Dependent Claim
29 words
A brake booster as defined by claim 2, which comprises a refill container on the tandem main cylinder in which said refill container is embodied as a three-chamber container.
Claim 10
Dependent Claim
29 words
A brake booster as defined by claim 3, which comprises a refill container on the tandem main cylinder in which said refill container is embodied as a three-chamber container.
Claim 11
Dependent Claim
29 words
A brake booster as defined by claim 4, which comprises a refill container on the tandem main cylinder in which said refill container is embodied as a three-chamber container.
Claim 12
Dependent Claim
29 words
A brake booster as defined by claim 5, which comprises a refill container on the tandem main cylinder in which said refill container is embodied as a three-chamber container.
Claim 13
Dependent Claim
29 words
A brake booster as defined by claim 6, which comprises a refill container on the tandem main cylinder in which said refill container is embodied as a three-chamber container.
Claim 14
Dependent Claim
33 words
A brake booster as defined by claim 1, which comprises a first position monitoring switch operable by a pin extending from a plate and a second position monitoring switch operable by a piston.
Claim 15
Dependent Claim
33 words
A brake booster as defined by claim 2, which comprises a first position monitoring switch operable by a pin extending from a plate and a second position monitoring switch operable by a piston.
Claim 16
Dependent Claim
33 words
A brake booster as defined by claim 3, which comprises a first position monitoring switch operable by a pin extending from a plate and a second position monitoring switch operable by a piston.
Claim 17
Dependent Claim
37 words
A brake booster as defined by claim 1, in which the pedal push rod includes a shoulder which serves as a rest for an axially aligned displaceable piston and said shoulder is equipped with a rubber disc.
Claim 18
Dependent Claim
37 words
A brake booster as defined by claim 4, in which the pedal push rod includes a shoulder which serves as a rest for an axially aligned displaceable piston and said shoulder is equipped with a rubber disc.
Claim 19
Dependent Claim
37 words
A brake booster as defined by claim 7, in which the pedal push rod includes a shoulder which serves as a rest for an axially aligned displaceable piston and said shoulder is equipped with a rubber disc.
Claim 20
Dependent Claim
37 words
A brake booster as defined by claim 13, in which the pedal push rod includes a shoulder which serves as a rest for an axially aligned displaceable piston and said shoulder is equipped with a rubber disc.
Claim 21
Dependent Claim
22 words
A brake booster as defined by claim 1, in which the dual-circuit tandem main cylinder is embodied as a stepped main cylinder.
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) | 1987-12-25 | 1988-06-25 | 1988-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-25 | 1992-06-25 | 1992-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-25 | 1996-06-25 | 1996-12-25 | $7700.00 | Window Closed / Lapsed |