Patent US3729790A successfully refreshed from Google Patents.
US3729790A
Expired / Lapsed
US
⏱️ 0.0 years remaining
A one-piece channel shaped piston ring
Assignee: Nippon Piston Ring Co Ltd
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Filing: 1970-10-29
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Granted: 1973-05-01
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Expires: 1990-10-29
Abstract
Abstract A piston ring has an electrolytic Cr plating applied to the surface of the channel shaped steel article prior to slitting by the grinder to form a plurality of lateral slits.
Inventors
- 👤 E Sugahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:52
CPC Classifications
B; B23; B23P; B23P15/00; B23P15/06; Y; Y10; Y10S; Y10S277/00; Y10S277/924; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49274; Y10T29/49281; Y10T29/49282
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
156 words
A method of producing a one-piece channel shaped piston ring comprising: forming in a thin steel sheet tape a plurality of like configured oil windows arranged alternately offset laterally on each side of the centerline of the steel sheet tape, bending the steel sheet tape along two lines parallel to said centerline to form a channel shaped article with a C shaped cross section, winding the obtained channel shaped article with the free edges of the sidewalls extending radially outwards spirally on a drum whose outer diameter is equal to the diameter of the piston ring groove in the piston receiving the same, subjecting the outer surfaces of the wound article to the electrolytic Cr plating treatment, and cutting a plurality of lateral slits with definite depths in both sidewalls in line with the oil windows but leaving a connecting part between each oil window and the end of each slit end in alternate side fashion.
Claim 2
Independent Claim
162 words
A method of producing a one-piece channel shaped piston ring comprising: forming in a thin steel sheet tape, a plurality of like configured oil windows arranged along a longitudinal centerline of said steel sheet at regular intervals, bending the steel sheet tape along two lines parallel to said centerline to form a channel shaped article of C shaped cross section, winding the obtained channel shaped article spirally with the free ends of said sidewalls extending radially outwardly on a drum having an outer diameter equal to the diameter of the piston ring groove in the piston receiving the same, subjecting the outer surfaces of the wound article to an electrolytic Cr plating treatment, cutting a plurality of lateral slits with definite depth in both sidewalls by means of a multiple head grinder to leave a connecting part between each oil window and each slit end at respective sidewalls, and cutting the obtained article into a plurality of segments having the desired length.
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) | 1976-04-30 | 1976-10-30 | 1977-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-30 | 1980-10-30 | 1981-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-30 | 1984-10-30 | 1985-05-01 | $7700.00 | Window Closed / Lapsed |