In 1608, Dutch eyeglass maker Hans Lipperhey filed the first patent for a working telescope. The patent was denied.
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| Number | Title | Issue Date |
| 7036823 | Side rail and combined oil control ring incorporated with the side rails for reduction of oil consumption A side rail is formed into a ring shape having its generally rectangular section that has an outer surface 3 formed with a pair of edge surfaces 5 of small radius, and an intermediate surface 6 of large radius of curvature formed between the edg... | 05/02/2006 |
| 6454271 | Combined oil ring A combined oil ring is comprised of an oil ring and an expander. The cross section of the oil ring is a generally I-shape, and the outer circumferential surfaces of outer rail portions form sliding surfaces to make contact with the cylinder wall surface. ... | 09/24/2002 |
| 5794941 | Piston ring assembly An improved piston ring assembly comprises a double-offset expander spring and a piston ring. The expander spring has a first wave portion that is continuously engaged in an annular groove of a piston body, the wave portion having an axial extent that is ... | 08/18/1998 |
| 5195758 | Three-piece oil control ring assembly A three-piece oil control ring includes a pair of radially split, generally flat annular rails which are supported in an axially spaced relationship by an annular spacer-expander. The expander defines alternating, axially symmetrical and generally U-shape... | 03/23/1993 |
| 5161805 | Oil ring assembly In a method of manufacturing a side rail of a compound steel oil ring assembly in which a linear, strip-like wire material is passed between a plurality of pins and bent into an annular shape, a side of the side rail that will become the inner circumferen... | 11/10/1992 |
| 5129661 | Steel oil ring assembly A steel oil ring assembly having an upper rail, a lower rail and an annular space-expander embraced by the rails and having radially extending or axially extending corrugations. The spacer is split at one circumferential location to form abutting end port... | 07/14/1992 |
| 5087055 | Steel oil ring assembly A steel oil ring assembly having an upper rail, a lower rail and an annular space-expander embraced by the rails and having radially extending or axially extending corrugations. The spacer is split at one circumferential location to form abutting end port... | 02/11/1992 |
| 4759266 | Multiple part oil-control ring for piston An oil control ring for a piston in an i.c. engine comprising an expander ring and two lamellar rails which scrape the oil from the cylinder wall. The expander ring has two series of lugs arranged alternately on each side, which support the rails and two ... | 07/26/1988 |
| 4585237 | Piston and oil control ring therefor A piston having a ring groove therearound has a three part oil control ring in the groove. The ring includes an axially and radially corrugated expander and two flat annular rails retained by the sides of the groove. The radial wall thickness of the rails... | 04/29/1986 |
| 4429885 | Spacer and expander member for holding and biasing piston ring rails A piston ring assembly including a pair of rails engageable with a cylinder wall and a spacer and expander member for holding and expanding the rails. The spacer and expander member has a corrugated base and arms extending alternately upwardly and downwar... | 02/07/1984 |
| 4411436 | Spring loaded piston seal assembly Spring loaded seals comprised of two resting rings positioned in an annular groove of a piston that are pressed against the upper and lower shoulders of the groove by a corrugated spring fitted therebetween. Each resting ring has at least one free-floatin... | 10/25/1983 |