US3874745A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anti-skid device for hydraulic brake mechanisms
Assignee: Fiat SpA
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Filing: 1974-05-09
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Granted: 1975-04-01
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Expires: 1994-05-09
Abstract
Abstract A hydraulic braking system has a master cylinder with two pistons linked by a spring and separating the cylinder into two working chambers, one of which is connected via a distributor valve to the brake cylinders and the other of which is connected in a pump circuit which directly feeds one control port of the distributor valve and feeds indirectly, via an anti-skid control valve, a second control port of the distributor valve. The braking circuit is arranged to provide anti-skid braking and also to operate at least some of the brakes even in the event of a pump failure or a rupture in the pump circuit.
Inventors
- 👤 Marco Peruglia
- 👤 Giuseppe Amedei
- 👤 Antonino Bertone
- 👤 Giulio Dotti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:47
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/26; B60T13/00; B60T13/10; B60T13/12; B60T13/16; B60T13/161; B60T8/32; B60T8/34; B60T8/44; B60T8/445
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
295 words
A hydraulic braking system for a motor vehicle, of the type comprising: at least one brake cylinder connected to a wheel of a first axle of said motor vehicle, a hydraulic fluid reservoir, a pump connected to the reservoir to draw fluid thereform, fluid control means connected downstream of said pump to receive fluid therefrom, means connecting said fluid control means to said reserVoir, first fluid conduit means connecting a circuit point between said pump and said fluid control means to said brake cylinder, wherein the improvement consists in said fluid control means including: a master cylinder closed at one end, a first port in said master cylinder connected to the output end of said pump, a second port in said master cylinder connected to said fluid reservoir, stop means projecting into said master cylinder, a first piston slidable within said master cylinder, said first piston having a passage interconnecting said first and second ports in said master cylindner when said first piston is in a rest position abutting against said stop means, restrictor throttle means in said piston, said restrictor throttle interconnecting said first and second ports when said piston is moved out of said rest position towards said one end of said master cylinder, thereby causing a restriction of the communication between said first and second ports, a first compression spring between said closed end of said master cylinder and said first piston, urging said first piston to abut against said stop means; a second piston slidable within said master cylinder on the opposite side of said stop means from said first piston, means linking said first piston to a brake pedal operable to urge said second piston towards said first piston, and a second compression spring between said first and second pistons.
Claim 2
Dependent Claim
295 words
A hydraulic braking system for a motor vehicle, of the type comprising: at least one brake cylinder connected to a wheel of a first axle of said motor vehicle, a hydraulic fluid reservoir, a pump connected to the reservoir to draw fluid thereform, fluid control means connected downstream of said pump to receive fluid therefrom, means connecting said fluid control means to said reserVoir, first fluid conduit means connecting a circuit point between said pump and said fluid control means to said brake cylinder, wherein the improvement consists in said fluid control means including: a master cylinder closed at one end, a first port in said master cylinder connected to the output end of said pump, a second port in said master cylinder connected to said fluid reservoir, stop means projecting into said master cylinder, a first piston slidable within said master cylinder, said first piston having a passage interconnecting said first and second ports in said master cylindner when said first piston is in a rest position abutting against said stop means, restrictor throttle means in said piston, said restrictor throttle interconnecting said first and second ports when said piston is moved out of said rest position towards said one end of said master cylinder, thereby causing a restriction of the communication between said first and second ports, a first compression spring between said closed end of said master cylinder and said first piston, urging said first piston to abut against said stop means; a second piston slidable within said master cylinder on the opposite side of said stop means from said first piston, means linking said first piston to a brake pedal operable to urge said second piston towards said first piston, and a second compression spring between said first and second pistons.
Claim 3
Dependent Claim
61 words
The hydraulic braking system of claim 1, wherein there are means defining a first chamber in said master cylinder, between said first piston and said one end of said master cylinder, and means defining a fluid transfer port, having a restrictor throtle therein, between said first chamber and a main conduit interconnecting said chamber and said at least one brake cylinder.
Claim 4
Dependent Claim
51 words
The hydraulic braking system of claim 2, wherein a one-way valve is connectd between said main conduit and said first port of said master cylinder and, said first chamber defined between said first piston and said one end of said master cylinder communicates with said second port in said master cylinder.
Claim 5
Dependent Claim
46 words
The hydraulic braking system of claim 2 wherein an anti-skid control device is connected in said main conduit, said anti-skid control device operating to release the braking pressure in said brake cylinder when the wheel associated with said brake cylinder is in an incipient skidding condition.
Claim 6
Dependent Claim
198 words
The hydraulic braking system of claiam 4, wherein a repeater valve is connected to at least one further brake cylinder of a wheel of a second axle of said motor vehicle, said repeater valve having: an inlet port, means connecting said inlet port to a second chamber in said master cylinder, said second chamber being defined between said first and second pistons of said master cylinder, an outlet port, means connecting said outlet port to said further brake cylinder, a first control port, means connecting said first control port to a point of said main conduit upstream of said anti-skid control device, a second control port, means connecting said second control port to a point of said main conduit downstream of said anti-skid control device, and said repeater valve operating to allow free communication between said inlet port and said outlet port for the flow of fluid therethrough when the fluid pressure at said first and second control ports is of similar magnitude, and operating to interrupt communication between said inlet and outlet ports when the pressure at said second control port falls to zero while the pressure at said first control port remains at a higher level.
Claim 7
Dependent Claim
198 words
The hydraulic braking system of claiam 4, wherein a repeater valve is connected to at least one further brake cylinder of a wheel of a second axle of said motor vehicle, said repeater valve having: an inlet port, means connecting said inlet port to a second chamber in said master cylinder, said second chamber being defined between said first and second pistons of said master cylinder, an outlet port, means connecting said outlet port to said further brake cylinder, a first control port, means connecting said first control port to a point of said main conduit upstream of said anti-skid control device, a second control port, means connecting said second control port to a point of said main conduit downstream of said anti-skid control device, and said repeater valve operating to allow free communication between said inlet port and said outlet port for the flow of fluid therethrough when the fluid pressure at said first and second control ports is of similar magnitude, and operating to interrupt communication between said inlet and outlet ports when the pressure at said second control port falls to zero while the pressure at said first control port remains at a higher level.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |