US3349875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Controlled torque drum brake
Assignee: ZF Active Safety US Inc
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Filing: 1965-06-25
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Granted: 1967-10-31
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Expires: 1985-06-25
Abstract
No abstract record available.
Inventors
- 👤 Stelzer William
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:32
CPC Classifications
F; F16; F16D; F16D65/00; F16D65/14; F16D65/16; F16D65/22; F16D51/00; F16D51/46; F16D51/48; F16D51/52; F16D2127/00; F16D2127/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
112 words
A DRUM BRAKE HAVING A PAIR OF ARCUATE BRAKE SHOES, MEANS CONNECTING SAID BRAKE SHOES AT ADJACENT ENDS THEREOF, A WHEEL CYLINDER ADJACENT THE OTHER ENDS OF SAID BRAKE SHOES, SAID WHEEL CYLINDER BEING CONNECTED TO A SOURCE OF FLUID PRESSURE, FIRST AND SECOND OPPOSED SERVICE PISTONS OF EQUAL SIZE OPERABLE TO MOVE SAID BRAKE SHOES IN A RADIALLY OUTWARD DIRECTION IN RESPONSE TO PRESSURE FROM A FLUID MOTOR, A VALVE OPERABLE TO INTERRUPT THE DELIVERY OF FLUID PRESSURE TO ONE OF SAID SERVICE PISTONS FROM SAID FLUID MOTOR AND PREVENT THE FURTHER PRESSURIZATION OF SAID ONE SERVICE PISTON WHILE KEEPING THE OTHER OF SAID SERVICE PISTONS OPEN TO SAID SOURCE OF
Claim 2
Dependent Claim
112 words
A DRUM BRAKE HAVING A PAIR OF ARCUATE BRAKE SHOES, MEANS CONNECTING SAID BRAKE SHOES AT ADJACENT ENDS THEREOF, A WHEEL CYLINDER ADJACENT THE OTHER ENDS OF SAID BRAKE SHOES, SAID WHEEL CYLINDER BEING CONNECTED TO A SOURCE OF FLUID PRESSURE, FIRST AND SECOND OPPOSED SERVICE PISTONS OF EQUAL SIZE OPERABLE TO MOVE SAID BRAKE SHOES IN A RADIALLY OUTWARD DIRECTION IN RESPONSE TO PRESSURE FROM A FLUID MOTOR, A VALVE OPERABLE TO INTERRUPT THE DELIVERY OF FLUID PRESSURE TO ONE OF SAID SERVICE PISTONS FROM SAID FLUID MOTOR AND PREVENT THE FURTHER PRESSURIZATION OF SAID ONE SERVICE PISTON WHILE KEEPING THE OTHER OF SAID SERVICE PISTONS OPEN TO SAID SOURCE OF
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) | 1970-10-30 | 1971-05-01 | 1971-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-10-30 | 1975-05-01 | 1975-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-10-30 | 1979-05-01 | 1979-10-31 | $7700.00 | Window Closed / Lapsed |