US4084671A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for wear warning in a servo operated disc clutch
Assignee: Volvo AB
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Filing: 1976-09-14
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Granted: 1978-04-18
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Expires: 1996-09-14
Abstract
Abstract A disc clutch servo mechanism cylinder has a signal bore extending from the cylinder working chamber to atmosphere. In normal operating state a pin seals this bore. The pin extends into the chamber and when the clutch is worn the piston will come close to the cylinder bottom and push the pin outwards. This movement causes the pin to open an air passage from the chamber to atmosphere, whereby an acoustic signal indicates clutch wear.
Inventors
- 👤 Runo Roy Oskar Ternehall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:58
CPC Classifications
F; F16; F16D; F16D66/00; F16D66/02; F16D25/00; F16D25/12
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
180 words
A compressed air operated servo mechanism for a disc clutch, especially for motor vehicles, comprising a servo piston (3) movable in a cylinder (2), the piston rod (4) of which is connected to the clutch and is disposed to disengage the same when compressed air is supplied to the cylinder working chamber (10) between the piston (3) and the bottom (6) of the cylinder (2); a valve (13,14), which controls a connection (17,20) between the working chamber (10) of the cylinder (2) and atmosphere and which in the normal operating state of the servo mechanism keeps the connection closed; means (13) connected with the valve for sensing the position of the piston and disposed so that when the piston (3), as a result of a worn clutch disc, assumes a position close to the bottom (6) of the cylinder it transfers the valve to its open position whereby air from the working chamber (10) flows through the connection (17,20) and gives an acoustic signal as well as a pressure signal in the clutch pedal so as to warn the driver.
Claim 2
Dependent Claim
180 words
A compressed air operated servo mechanism for a disc clutch, especially for motor vehicles, comprising a servo piston (3) movable in a cylinder (2), the piston rod (4) of which is connected to the clutch and is disposed to disengage the same when compressed air is supplied to the cylinder working chamber (10) between the piston (3) and the bottom (6) of the cylinder (2); a valve (13,14), which controls a connection (17,20) between the working chamber (10) of the cylinder (2) and atmosphere and which in the normal operating state of the servo mechanism keeps the connection closed; means (13) connected with the valve for sensing the position of the piston and disposed so that when the piston (3), as a result of a worn clutch disc, assumes a position close to the bottom (6) of the cylinder it transfers the valve to its open position whereby air from the working chamber (10) flows through the connection (17,20) and gives an acoustic signal as well as a pressure signal in the clutch pedal so as to warn the driver.
Claim 3
Dependent Claim
40 words
A servo mechanism according to claim 1, characterized in that the valve comprises an externally observable valve member (13,24) which assumes a warning position in the open position of the valve, thereby giving an optical indication of the clutch condition.
Claim 4
Dependent Claim
97 words
A servo mechanism according to claim 1, characterized in that said means comprises a pin (13) displaceably disposed in an axial bore (14,20) in the bottom (6) of the cylinder with its inner end extending into the path of motion of the piston (3) near the bottom (6) of the cylinder, that the pin (13) in its inner normal position, unaffected by the piston (3), seals the bore shut, and that the pin (13), in an outwardly displaced signalling position caused by the motion of the piston (3), opens an air flow path through the bore (14,20).
Claim 5
Dependent Claim
90 words
A servo mechanism according to claim 3, characterized in that the pin (13) in its normal position extends with its outer end beyond the bottom (6) of the cylinder and is provided at its outer end (24) with a radially extending deformable means (25), which follows the extension motion of the pin (13) to the signalling position, and that a fixed stop (27) is so disposed in the path of motion of the means (25) that it deforms the means (25) when the pin (13) moves to the signalling position.
Claim 6
Dependent Claim
52 words
A servo mechanism according to claim 4, characterized in that the pin (13) is provided with an additional radially extending means (28) such as a flange or washer, which is disposed to rest against the stop (27) in the signalling position of the pin (13) and prevent further extension of the pin.
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) | 1981-04-17 | 1981-10-17 | 1982-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-17 | 1985-10-17 | 1986-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-17 | 1989-10-17 | 1990-04-18 | $7700.00 | Window Closed / Lapsed |