US4177773A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Damped automatic variable valve timing device for internal combustion engines
Assignee: Individual
•
Filing: 1977-12-27
•
Granted: 1979-12-11
•
Expires: 1997-12-27
Abstract
Abstract A variable drive means for cam-operated intake and exhaust valves in an internal combustion engine, the variation being responsive to changes in load and rpm of the engine while the engine is running and being completely automatic. The disclosed device provides a slip drive for the camshaft, virtually unaffected by wear and with a predictable, constantly damped biasing action making the device suitable for mass production to suit any engine and preventing vibration and rough operation of the engine and giving automatic wear compensation.
Inventors
- 👤 John R. Cribbs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:06
CPC Classifications
F; F01; F01L; F01L1/00; F01L1/34; F01L1/344; F01L1/34409; F01L2303/00; F01L2303/01; Y; Y10; Y10T; Y10T74/00; Y10T74/21; Y10T74/2101; Y10T74/2102
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
137 words
An automatic variable cam drive for internal combustion engines having a crankshaft and a camshaft, said cam drive comprising: a face plate fixed to a camshaft; a sprocket mounted for limited rotation on said face plate axially of said camshaft and positively driven in one direction by a crankshaft; a resilient drive coupling operatively mounted on and between said face plate and sprocket and producing a bias in said face plate and camshaft to turn with said sprocket in said direction, whereby gas load reaction to high crankshaft rpm overcomes said bias and said face plate and camshaft have a relative shifting movement to a rotationally retarded position to give a like retarded valve timing; and spring means operatively positioned between said face plate and the positively driven sprocket to dampen and smooth out said shifting movement.
Claim 2
Dependent Claim
137 words
An automatic variable cam drive for internal combustion engines having a crankshaft and a camshaft, said cam drive comprising: a face plate fixed to a camshaft; a sprocket mounted for limited rotation on said face plate axially of said camshaft and positively driven in one direction by a crankshaft; a resilient drive coupling operatively mounted on and between said face plate and sprocket and producing a bias in said face plate and camshaft to turn with said sprocket in said direction, whereby gas load reaction to high crankshaft rpm overcomes said bias and said face plate and camshaft have a relative shifting movement to a rotationally retarded position to give a like retarded valve timing; and spring means operatively positioned between said face plate and the positively driven sprocket to dampen and smooth out said shifting movement.
Claim 3
Dependent Claim
21 words
Apparatus according to claim 1 wherein said spring means includes a Bellville spring effectively pressing said face plate against said sprocket.
Claim 4
Dependent Claim
63 words
Apparatus according to claim 1 wherein said resilient drive includes a coil spring having one end captured in said face plate and the other end engaged with a stop on said sprocket; a second stop on said sprocket; and stop-engaging means on said face plate to engage said second stop and being capable of measured adjustment for variably limiting said relative shifting movement.
Claim 5
Dependent Claim
31 words
Apparatus according to claim 2 wherein anti-galling washers are inserted on the wear surfaces of the web of said sprocket enabling said Bellville spring to exert strong axial thrust without galling.
References Cited (Backward Citations)
US2899810A
Cited
US2121560A
Cited
US2977778A
Cited
US3262435A
Cited
US3285095A
Cited
US3357358A
Cited
DE1810368A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-10 | 1983-06-11 | 1983-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-10 | 1987-06-11 | 1987-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-10 | 1991-06-11 | 1991-12-11 | $7700.00 | Window Closed / Lapsed |