Patent US2603170A successfully refreshed from Google Patents.
Patent US3756660A successfully refreshed from Google Patents.
US3756660A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-circuit brake system
Assignee: TDK Micronas GmbH
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Filing: 1971-08-12
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Granted: 1973-09-04
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Expires: 1991-08-12
Abstract
Abstract A two brake circuit pedal master cylinder provides brake fluid pressure for the control valve of a vacuum brake booster and two intermediate master cylinders each coupled to the wheel cylinders of a different brake circuit. A single booster cylinder operated by the brake booster also provides brake fluid pressure for the two intermediate master cylinders. The two intermediate master cylinders are integral in construction. A pair of blind bores are formed in a housing parallel to each other and the longitudinal axis of the housing. Each bore is part of a different intermediate master cylinder, divided longitudinally into two chambers and filled with brake fluid. The first chamber of each bore includes a valve piston operated on hydraulically by the brake fluid pressure from the pedal master cylinder to activate the brake circuit associated with that particular intermediate master cylinder. The second chamber of each bore includes a secondary piston carrying a locking member mechanically operable on the associated valve piston when the booster cylinder applies brake fluid pressure to the secondary piston. The cylindrical member forming the second chamber and carrying the secondary piston is threaded into its associated bore.
Inventors
- 👤 J Burgdorf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:39
CPC Classifications
B; B60; B60T; B60T11/00; B60T11/10; B60T11/24; B60T11/16; B60T11/20; B60T11/203; B60T13/00; B60T13/10; B60T13/24; B60T13/241; B60T13/246; B60T13/249
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
185 words
A multi-circuit brake system comprising: a pedal master cylinder having at least two outputs capable of supplying brake fluid to at least two brake fluid lines; a vacuum brake booster; a single control valve connected to each of said two lines adjacent said outputs of said pedal master cylinder and to said booster in a control relationship therewith; a booster cylinder connected in operative relationship with said booster, said booster cylinder having a single brake fluid output; at least two intermediate master cylinders, each of said intermediate master cylinders being connected in common with said single output of said booster cylinder and to a different one of said two lines adjacent said outputs of said pedal master cylinder, both of said intermediate master cylinders being subjected to brake fluid pressure from said pedal master cylinder and said booster cylinder when said brake booster is operative and being subjected to brake fluid pressure from only said pedal master cylinder when said brake booster is inoperative; and at least two brake circuits each connected to and under control of a different one of said intermediate master cylinders.
Claim 2
Dependent Claim
185 words
A multi-circuit brake system comprising: a pedal master cylinder having at least two outputs capable of supplying brake fluid to at least two brake fluid lines; a vacuum brake booster; a single control valve connected to each of said two lines adjacent said outputs of said pedal master cylinder and to said booster in a control relationship therewith; a booster cylinder connected in operative relationship with said booster, said booster cylinder having a single brake fluid output; at least two intermediate master cylinders, each of said intermediate master cylinders being connected in common with said single output of said booster cylinder and to a different one of said two lines adjacent said outputs of said pedal master cylinder, both of said intermediate master cylinders being subjected to brake fluid pressure from said pedal master cylinder and said booster cylinder when said brake booster is operative and being subjected to brake fluid pressure from only said pedal master cylinder when said brake booster is inoperative; and at least two brake circuits each connected to and under control of a different one of said intermediate master cylinders.
Claim 3
Dependent Claim
18 words
A system according to claim 1, further including a brake fluid reservoir connected to said pedal master cylinder.
Claim 4
Dependent Claim
25 words
A system according to claim 1, further including a brake fluid reservoir connected in common to both said intermediate master cylinders and said booster cylinder.
Claim 5
Dependent Claim
38 words
A system according to claim 1, further including a first brake fluid reservoir connected to said pedal master cylinder; and a second brake fluid reservoir connected in common to both said intermediate master cylinders and said booster cylinder.
Claim 6
Dependent Claim
339 words
A system according to claim 1, wherein said two intermediate master cylinders include a housing having a longitudinal axis, two bores in said housing disposed in spaced parallel relationship to each other and said longitudinal axis, each of said bores having an open end connected to said booster cylinder and a closed end, a valve piston disposed in each of said bores and displaceable longitudinally thereon, a spring engaging each of said valve pistons and said closed end of the associated one of said bores, a secondary piston having a locking member disposed in each of said bores and displaceable longitudinally therein, each of said locking members extending from one surface of the associated one of said secondary piston toward the associated one of said valve pistons, each of said locking members having an end engaging the associated one of said valve pistons for movement thereof when said brake booster is operative, the other surface of each of said secondary pistons being disposed adjacent said open end of the associated one of said bores, and a member disposed transversely of each of said bores to slidably receive the associated one of said locking members and cooperating to form two chambers in series relation with respect to each other in the associated one of said bores, each of said chambers being filled with brake fluid, the first of said chambers in each of said bores is formed by said closed end of the associated one of said bores and the associated one of said members and is connected to a different one of said brake circuits and a different one of said brake fluid lines and contains the associated one of said valve pistons, the second of said chambers in each of said bores is formed by the associated one of said members and said secondary piston, each of said valve pistons being hydraulically displaced by means of said pedal master cylinder and being mechanically displaced by the associated one of said locking members when said brake booster is operative.
Claim 7
Dependent Claim
63 words
A system according to claim 5, wherein said second chamber of one of said bores is connected to be in communication with a non-pressurized portion of said booster cylinder and a brake fluid reservoir, and said second chamber of the other of said bores is connected to said second chamber of said one of said bores by a transverse duct in said housing.
Claim 8
Dependent Claim
32 words
A system according to claim 6, wherein each of said bores are stepped to provide said bore with a larger diameter in said second chamber than the diameter in said first chamber.
Claim 9
Dependent Claim
26 words
A system according to claim 7, wherein the effective surfaces of each of said valve pistons and each of said secondary pistons are different in size.
Claim 10
Dependent Claim
68 words
A system according to claim 8, wherein said open end of each of said bores is threaded, each of said second chambers are defined by a cylindrical member carrying the associated one of said secondary pistons, and each of said cylindrical members have their external surface threaded to enable each of said cylindrical members to be threaded into said open end of the associated one of said bores.
Claim 11
Dependent Claim
67 words
A system according to claim 5, wherein said open end of each of bores is threaded, each of said second chambers are defined by a cylindrical member carrying the associated one of said secondary pistons, and each of said cylindrical members have their external surface threaded to enable each of said cylindrical members to be threaded into said open end of the associated one of said bores.
References Cited (Backward Citations)
US3550377A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |