Issued Patents All Time
Showing 1–8 of 8 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6766570 | Coupling units connecting tubular members having a hardened inner wall for carrying mechanically abrasive fluid concrete | Gary D. Lehnhardt | 2004-07-27 |
| 6467812 | Pipe having replaceable wear resistant lined coupler | Gary D. Lehnhardt | 2002-10-22 |
| 6375228 | Coupling units connecting tubular members having a hardened inner wall for carrying mechanically abrasive fluid concrete | Gary D. Lehnhardt | 2002-04-23 |
| 5379805 | Single solid thin wall pipe for abrasive material having a gradual transition in hardness | Gary D. Lehnhardt | 1995-01-10 |
| 5097585 | Method of forming a composite tubular unit by expanding, low-frequency induction heating and successively quenching | — | 1992-03-24 |
| 4796814 | Semi-liquid cementitious spray nozzle apparatus | Gary D. Lehnhardt | 1989-01-10 |
| 4640533 | Adjustable pipe extender for high pressure lines carrying abrasive materials | — | 1987-02-03 |
| 4354737 | Variable gain screen permitting off-axis viewing with image brightness remaining constant | Martin Dotsko, David L. Peters | 1982-10-19 |