Did You Know...
...that Thomas Edison's patent application on his phonograph was approved by the Patent Office in just seven weeks? In contrast, it took Gordon Gould, the inventor of the laser, 30 years to obtain his patent -- finally awarded in 1988!
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| Number | Title | Issue Date |
| 5271315 | Pressure balanced piston rings Force balanced (or nearly balanced) rings to eliminate (or greatly reduce) pressure caused force build up of the ring(s) against the cylinder wall. Especially important in high pressure engines and/or where increased depth ring/cylinder contact surface is... | 12/21/1993 |
| 4966068 | Split ceramic piston ring arrangement with nested biasing ring A piston-ring arrangement for use in an internal combustion engine including a cylinder with a piston axially displaceable within the cylinder and at least one piston ring guided in the cylinder. The cylinder, piston and piston-ring are made of a ceramic ... | 10/30/1990 |
| 4719938 | Self-cleaning valve and cryopump utilizing the same The pressure relief valve is debris resistant, self-cleaning, and self-actuating in a cryopump. It includes an o-ring carried by a valve member within a valve cylinder. In opening, the valve member moves away from an end port to open vent ports in the sid... | 01/19/1988 |
| 4615261 | Stirling engine with improved piston ring assembly An improved piston ring assembly, particularly for a Stirling engine, comprises a piston ring made from a TFE fluorocarbon such as Rulon which is disposed in a piston ring groove and is acted upon by an annular bi-metal element disposed between the groove... | 10/07/1986 |
