Patent US5559314A successfully refreshed from Google Patents.
Patent US4214448A successfully refreshed from Google Patents.
US4214448A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic brake booster
Assignee: ITT Inc
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Filing: 1978-06-19
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Granted: 1980-07-29
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Expires: 1998-06-19
Abstract
Abstract There is disclosed a hydraulic brake booster comprising a valve spool providing for alternate connection of a booster chamber with a source of pressure-transmitting fluid and an unpressurized return reservoir. The source of pressure-transmitting fluid is a pump-circulated fluid adapted to be throttled by a mechanically actuatable throttle valve arranged coaxially with the valve spool. Since the throttle valve is actuated independently of the pressure in the booster chamber, the need to produce a supply pressure when the brake is not actuated is eliminated. The pump is subjected to load only during the relatively short period of brake activation.
Inventors
- 👤 Juan Belart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:02
CPC Classifications
B; B60; B60T; B60T13/00; B60T13/10; B60T13/12; B60T13/16; B60T13/161; B60T13/162; B60T13/163
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
213 words
A hydraulic brake booster comprising: a housing having a longitudinal axis; a booster piston disposed in and slidably sealed to an inner surface of said housing coaxial of said axis, one end of said booster piston adjacent a brake pedal providing a boundary for a booster chamber; a valve spool disposed within and slidably sealed to an inner surface of said booster piston, said valve spool being slidable by said brake pedal to provide alternate connection of said booster chamber with a source of pressure-transmitting fluid and an unpressurized return reservoir, said source of pressure-transmitting fluid being a pump circulating a brake fluid; a static master cylinder having a master piston disposed within said housing coaxial of said axis spaced from the other end of said booster piston, said master piston being activated by said booster piston through a push rod disposed within said housing coaxial of said axis; and a controlled flow-control valve disposed within said housing coaxial of said axis between said booster piston and said master cylinder, said flow control valve including a valve member disposed within said housing and coaxially around said push rod, said push rod causing said valve member to be displaced mechanically in a direction towards said master piston to obtain throttling of said pump-circulated fluid.
Claim 2
Dependent Claim
213 words
A hydraulic brake booster comprising: a housing having a longitudinal axis; a booster piston disposed in and slidably sealed to an inner surface of said housing coaxial of said axis, one end of said booster piston adjacent a brake pedal providing a boundary for a booster chamber; a valve spool disposed within and slidably sealed to an inner surface of said booster piston, said valve spool being slidable by said brake pedal to provide alternate connection of said booster chamber with a source of pressure-transmitting fluid and an unpressurized return reservoir, said source of pressure-transmitting fluid being a pump circulating a brake fluid; a static master cylinder having a master piston disposed within said housing coaxial of said axis spaced from the other end of said booster piston, said master piston being activated by said booster piston through a push rod disposed within said housing coaxial of said axis; and a controlled flow-control valve disposed within said housing coaxial of said axis between said booster piston and said master cylinder, said flow control valve including a valve member disposed within said housing and coaxially around said push rod, said push rod causing said valve member to be displaced mechanically in a direction towards said master piston to obtain throttling of said pump-circulated fluid.
Claim 3
Dependent Claim
36 words
A hydraulic brake booster according to claim 1, wherein said valve member is movable relative to said push rod and is movable by said push rod in a direction towards said master piston via a spring.
Claim 4
Dependent Claim
30 words
A hydraulic brake booster according to claim 2, wherein said valve member includes a pressure-bearing surface having applied thereto said pump-circulated fluid in opposition to the force of said spring.
Claim 5
Dependent Claim
36 words
A hydraulic brake booster according to claim 3, wherein said pressure-bearing surface is an annular surface formed by a step in said valve member, said annular surface having a throttling shoulder on the outer periphery thereof.
Claim 6
Dependent Claim
41 words
A hydraulic brake booster according to claim 2, wherein the displacement of said valve member relative to said push rod in a direction toward said master piston is limited by a stop formed on the outer surface of said push rod.
Claim 7
Dependent Claim
45 words
A hydraulic brake booster according to claim 5, wherein the displacement of said valve member relative to a portion of said housing in a direction towards said booster piston is limited by a stop formed in the inner surface of said portion of said housing.
Claim 8
Dependent Claim
86 words
A hydraulic brake booster according to claim 1, further including a spring disposed within said housing coaxial of said axis between said valve spool and said booster piston, said spring being so dimensioned that said booster piston, at the commencement of a braking action when no substantial counter-force is applied to said booster piston from said master cylinder, is displaced mechanically at least to such an extent that said valve member reaches its closing position before said valve spool connects said booster chamber with said pump.
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) | 1983-07-29 | 1984-01-28 | 1984-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-29 | 1988-01-28 | 1988-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-29 | 1992-01-28 | 1992-07-29 | $7700.00 | Window Closed / Lapsed |