Patent US3608678A successfully refreshed from Google Patents.
US3608678A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spot-type disc brake
Assignee: Aisin Corp
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Filing: 1969-10-02
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Granted: 1971-09-28
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Expires: 1989-10-02
Abstract
Abstract A spot-type disc brake having a dual circuit from a master cylinder wherein four pistons are provided in a single hydraulic cylinder located on a stationary member so as to constitute two independent hydraulic chambers to which pressurized fluid is applied through each fluid passage for braking, and one of the pistons is adapted to be actuated mechanically by a hand-lever for parking.
Inventors
- 👤 Toyoaki Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:54
CPC Classifications
F; F16; F16D; F16D55/00; F16D55/02; F16D55/22; F16D55/224
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
343 words
A spot-type disc brake comprising, in combination, a rotatable brake disc, a pair of friction pad assemblies disposed on opposite sides of said brake disc, a movable yoke member for directly actuating a first friction pad, an open-ended hydraulic cylinder stationarily mounted on one side of said brake disc, a first piston slidably mounted in said cylinder and having an inner end wall acting directly on the second friction pad, a second annular piston slidably mounted in said cylinder and provided with means at its outer end for mechanically actuating said movable yoke member, a third piston slidably mounted in said first and second pistons and having an inner end wall engaging the inner side of the end wall of said first piston, said first, second and third pistons providing a first fluid chamber between said first and second pistons, said third piston also provided with means at its outer end for being mechanically actuated, a fourth piston slidably mounted in said third piston and normally engaging the inside of the inner end wall of said third piston, said third and fourth pistons providing a second fluid chamber, the outer end of said fourth piston engaging said movable yoke member, a service braking device mounted on said movable yoke member and having means for actuating said third piston, whereby when hydraulic fluid is introduced separately into the first and second fluid chambers to force the first and second pistons apart and to force the third and fourth pistons apart in opposite directions, said first piston will actuate the second friction pad against said brake disc and the means at the outer end of said second piston and the outer end of said fourth piston will actuate said movable yoke member to actuate the first friction pad against said brake disc, and whereby, upon failure of the fluid to one of the fluid chambers, the service braking device may be operated to actuate said friction pads to supplement the force lost by the failure of the fluid to said one of the fluid chambers.
Claim 2
Dependent Claim
343 words
A spot-type disc brake comprising, in combination, a rotatable brake disc, a pair of friction pad assemblies disposed on opposite sides of said brake disc, a movable yoke member for directly actuating a first friction pad, an open-ended hydraulic cylinder stationarily mounted on one side of said brake disc, a first piston slidably mounted in said cylinder and having an inner end wall acting directly on the second friction pad, a second annular piston slidably mounted in said cylinder and provided with means at its outer end for mechanically actuating said movable yoke member, a third piston slidably mounted in said first and second pistons and having an inner end wall engaging the inner side of the end wall of said first piston, said first, second and third pistons providing a first fluid chamber between said first and second pistons, said third piston also provided with means at its outer end for being mechanically actuated, a fourth piston slidably mounted in said third piston and normally engaging the inside of the inner end wall of said third piston, said third and fourth pistons providing a second fluid chamber, the outer end of said fourth piston engaging said movable yoke member, a service braking device mounted on said movable yoke member and having means for actuating said third piston, whereby when hydraulic fluid is introduced separately into the first and second fluid chambers to force the first and second pistons apart and to force the third and fourth pistons apart in opposite directions, said first piston will actuate the second friction pad against said brake disc and the means at the outer end of said second piston and the outer end of said fourth piston will actuate said movable yoke member to actuate the first friction pad against said brake disc, and whereby, upon failure of the fluid to one of the fluid chambers, the service braking device may be operated to actuate said friction pads to supplement the force lost by the failure of the fluid to said one of the fluid chambers.
Claim 3
Dependent Claim
44 words
A spot-type disc brake as claimed in claim 1 wherein said fourth piston includes an inlet port through which fluid under pressure is supplied to said second fluid chamber and an outlet port through which any air within said second fluid chamber is expelled.
Claim 4
Dependent Claim
40 words
A spot-type disc brake as claimed in claim 1 wherein the means at the outer end of said second piston comprises a pair of projections disposed on each side of the main axis thereof for engagement with said movable member.
Claim 5
Dependent Claim
24 words
A spot-type disc bRake as claimed in claim 1 wherein said service braking device comprises bellcrank lever means pivotally mounted on said movable member.
Claim 6
Dependent Claim
33 words
A spot-type disc brake as claimed in claim 4 wherein said bellcrank lever means comprises a pair of coupled bellcrank levers disposed at each side of the main axis of said hydraulic cylinder.
Claim 7
Dependent Claim
41 words
A spot-type disc brake as claimed in claim 5 wherein the means at the outer end of said third piston comprises two pairs of projections disposed at each side of the main axis thereof for engagement with said coupled bellcrank levers.
References Cited (Backward Citations)
US3372778A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-27 | 1975-03-29 | 1975-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-27 | 1979-03-29 | 1979-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-27 | 1983-03-29 | 1983-09-28 | $7700.00 | Window Closed / Lapsed |