Famous Patents
3M employee and church chorister Art Fry needed something to temporarily mark pages in his hymnal. He was in luck because his colleague, Spencer Silver, accidentally developed a glue that was too weak for other purposes. After initially discouraging consumer response, Post-it Notes became a hit in 1979.
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| Number | Title | Issue Date |
| 7252292 | Oil ring for an internal combustion engine An oil ring for an internal combustion engine, comprising a metallic annular body (10) to be mounted around a piston (P) reciprocating inside a cylinder (C) of the engine, said annular body (10) having opposite lateral faces (11), an internal fa... | 08/07/2007 |
| 6230379 | Combined machining apparatus for making piston rings A combined apparatus for making piston rings is disclosed which is provided with an interior-exterior working machine (1) operable under synchronous control by an NC unit (36) for machining both inside and outside of a workpiece (16) composed of a stack o... | 05/15/2001 |
| 5966807 | Manufacturing piston rings A method of manufacturing piston rings from a tube blank includes cutting a longitudinal slot in the tube blank, applying a force to the tube blank so that the slot is at least partially closed and the tube has a stressed shape, securing the stressed tube... | 10/19/1999 |
| 5469616 | Method of manufacturing a side rail of a combined oil ring Each side rail of a combined oil ring, which includes a spacer-expander and two side rails, has an ion nitriding treatment layer on an outer peripheral surface of the rail. The inner peripheral surface of each rail may either be a bare surface or have eit... | 11/28/1995 |
| 5461776 | Method of manufacturing piston rings A method for the manufacture of piston rings, includes the steps of producing a tube and machining the desired ring free shapes on the inner and outer diameters of the tube providing desired cross sectional profiles by grinding, for example, and then cutt... | 10/31/1995 |
| 5430938 | Method of making and using a piston ring assembly Method of making a piston ring assembly by providing a metallic (i.e. cast aluminum) piston with a crown and an annular depending side wall; machining a stepped annular groove in the side wall having a total height of at least 4 mm (preferably having a co... | 07/11/1995 |
| 5241748 | Method for manufacturing a compression ring A compression ring provided with both ends having notches is formed on outer peripheral surface with a plasma nitrided layer and is formed on upper and lower surfaces and an inner peripheral surface with soft surface treatment layers. The upper and lower ... | 09/07/1993 |
| 5230149 | Method of manufacturing a hydraulic seal A method of manufacturing a ring-shaped hydraulic seal (10) produces a cylindrical sealing surface (12) having portions (24) formed of a plastic material and portions (26) formed of an elastomeric material. The method includes the steps of forming a plast... | 07/27/1993 |
| 4986168 | Piston and multilayer piston ring set Compression piston ring for internal combustion or compressor cylinder and piston comprising double layer of segmented ring sectors having free form circumferential curvature matching the cylinder bore. The double layers are adapted to effectively seal or... | 01/22/1991 |
| 4862777 | Method and apparatus for forming surfaces on piston rings Apparatus is described for machining the exterior peripheral surface of piston rings for internal combustion engines, particularly piston rings having a transverse shape other than circular, for example, oval or elliptical. A jig arrangement usable with t... | 09/05/1989 |
| 4856105 | Method and apparatus for making piston rings A method of making self-tensioning rings, including the steps of circumferentially machining an out-of-round ring blank on inner and outer surfaces thereof and subsequently cutting a ring segment out of the ring for obtaining a ring gap therein; measuring... | 08/08/1989 |
| 4576381 | Spiral piston ring with tapered ends and recesses A spiral piston ring made of self-lubricating material and having at least two complete convolutions and having a gradual and continuous taper except for the terminal portions thereof which taper at a steeper angle than the gradual and continuous taper, a... | 03/18/1986 |
| 4531985 | Surface treatment of metal rings A metal ring of generally rectangular cross-section has its radially outer surface and its side surfaces treated by being stacked with its sides in contact with other rings in a chamber. Air is excluded from the chamber and a gaseous mixture of a carburiz... | 07/30/1985 |
| 4463487 | Method of manufacturing piston rings The manufacture of piston rings for internal combustion engines comprises making a ring blank of which the diameter over the outer periphery is greater, and the diameter within the inner periphery is less than that required in the finished ring. A gap is ... | 08/07/1984 |
| 4299401 | Piston ring and method of making same A piston ring is to be mounted in a groove in a piston. The piston ring has sidewalls for engaging sidewalls of the piston ring groove. Each of the sidewalls of the piston ring is hardened in respective localized areas. The localized areas each include a ... | 11/10/1981 |
| 4176434 | Method of making piston rings with chrome-filled grooves A method of making piston rings comprising forming annular stepped grooves in the outer periphery of a plurality of piston ring blanks, stacking the blanks on a rotatable arbor, electro-depositing a layer of chromium in the grooves and on the outer surfac... | 12/04/1979 |
| 4141263 | Device for the centered clamping of annular workpieces A device for the centered clamping, in a turning machine, of an annular workpiece or workpiece stack formed of a plurality of annular workpieces, has a centering cylinder; an arrangement for axially displacing the centering cylinder; first and second axia... | 02/27/1979 |
| 4024748 | Apparatus for producing annular metallic blanks for metallic rings An apparatus for producing annular metallic blanks for metallic rings having a desired inner diameter wherein a length of elongated metallic material having a predetermined cross-sectional configuration is formed into a spiral shape having an inner diamet... | 05/24/1977 |
| 3991455 | Coupled piston ring method of manufacture A ring assembly includes two side-by-side flat ring members of uniform rectangular cross-section each being split, with the confronting split ends having radially overlapping fingers to define a circumferentially sealing joint. The ring members are dimens... | 11/16/1976 |
| 3938235 | Method for severing rings from a coil A helical coil comprising a plurality of turns of bar stock is mounted on an expanding mandrel which is operated by a hydraulic cylinder or the like to expand the internal circumference of the coil against the resilient resistance thereof. A severing devi... | 02/17/1976 |
