Patent US3792433A successfully refreshed from Google Patents.
US3792433A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Master cylinder for hydraulic braking system
Assignee: Aisin Corp
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Filing: 1972-04-17
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Granted: 1974-02-12
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Expires: 1992-04-17
Abstract
Abstract This invention relates to a master cylinder for hydraulic braking system including a cylinder body, a bore formed in the body, a fluid displacing piston slidably mounted within the bore and having primary and secondary cups, a poppet valve interposed between a reservoir and a chamber formed in the bore for closing communication between the reservoir and the chamber against the fluid pressure in the chamber and for opening the communication therebetween against the fluid pressure in the reservoir, the poppet valve and the secondary cup act with the primary cup to form an airtight chamber filled with oil, a first warning of device for warning the failure of the primary cup, a second warning device for warning that the level of the brake fluid in the reservoir is low, and a third warning device for warning when the pressure the brake fluid in the reservoir is below a certain pressure.
Inventors
- 👤 T Wada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:28
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/30; G01F23/56; B; B60; B60T; B60T11/00; B60T11/10; B60T11/16; B60T11/22; B60T17/00; B60T17/18; B60T17/22; B60T17/225
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
245 words
A master cylinder for a hydraulic braking system having a fluid reservoir connected thereto comprising, a cylinder body provided with a bore therein, a piston axially slidably mounted in the bore of said cylinder body and operably connected to a brake pedal, to provide a first chamber at one end of said cylinder, biasing means disposed within said first chamber for urging said piston to the brake release position, a primary and a secondary sealing cup mounted on opposed ends of said piston for providing seals between the bore and the piston, said piston being provided with an annular recess between said sealing cups to form a second chamber, a first passage for fluid communication between the reservoir and said second chamber and a second passage for fluid communication between said second chamber and said first chamber, said second passage being cOntrolled by said primary sealing cup, a third passage formed in said cylinder body for fluid communication between said first chamber, said second chamber and said reservoir, said third passage being closed when said piston is moved to increase the hydraulic pressure in said first chamber against said biasing means, a poppet valve for controlling communication between the reservoir and said second chamber, and means for closing said poppet valve when said piston is moved to increase pressure in said first chamber and in said second chamber, whereby said secondary sealing cup serves to pressurize said first chamber when said primary sealing cup fails.
Claim 2
Dependent Claim
245 words
A master cylinder for a hydraulic braking system having a fluid reservoir connected thereto comprising, a cylinder body provided with a bore therein, a piston axially slidably mounted in the bore of said cylinder body and operably connected to a brake pedal, to provide a first chamber at one end of said cylinder, biasing means disposed within said first chamber for urging said piston to the brake release position, a primary and a secondary sealing cup mounted on opposed ends of said piston for providing seals between the bore and the piston, said piston being provided with an annular recess between said sealing cups to form a second chamber, a first passage for fluid communication between the reservoir and said second chamber and a second passage for fluid communication between said second chamber and said first chamber, said second passage being cOntrolled by said primary sealing cup, a third passage formed in said cylinder body for fluid communication between said first chamber, said second chamber and said reservoir, said third passage being closed when said piston is moved to increase the hydraulic pressure in said first chamber against said biasing means, a poppet valve for controlling communication between the reservoir and said second chamber, and means for closing said poppet valve when said piston is moved to increase pressure in said first chamber and in said second chamber, whereby said secondary sealing cup serves to pressurize said first chamber when said primary sealing cup fails.
Claim 3
Dependent Claim
23 words
A master cylinder as claimed in claim 1 and further comprising a first warning device responsive to failure of said primary sealing cup.
Claim 4
Dependent Claim
39 words
A master cylinder as claimed in claim 2, wherein said first warning device comprises a switch responsive to an increase in pressure of the fluid within said second chamber, and a warning lamp responsive to said pressure responsive switch.
Claim 5
Dependent Claim
32 words
A master cylinder as claimed in claim 2 and further comprising a second warning device responsive to the level of the fluid in the reservoir when it falls below a predetermined level.
Claim 6
Dependent Claim
56 words
A master cylinder as claimed in claim 4 wherein said second warning device comprises a float movable in response to the vertical movement of the fluid surface within the reservoir, a contact switch, said float closing said contact switch when said float is lowered a predetermined amount, and a warning lamp responsive to said contact switch.
Claim 7
Dependent Claim
37 words
A master cylinder as claimed in claim 2 and further comprising a third warning device responsive to decreased fluid pressure within the reservoir below a predetermined value due to failure of fluid pressure at a brake cylinder.
Claim 8
Dependent Claim
60 words
A master cylinder as claimed in claim 6, wherein said third warning device comprises a diaphragm piston operable when the fluid within the reservoir is decreased, a plate connected to said diaphragm piston, a contact switch, said plate closing said contact switch when said plate is moved with said diaphragm piston, and a warning lamp responsive to said contact switch.
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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |