Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5178494 | Roof support for underground excavations such as coal mines | Alfred Zitz, Karl Lerchbaum | 1993-01-12 |
| 4404893 | Hydraulic mine prop | Siegfried Sigott, Alfred Zitz, Gottfried Siebenhofer | 1983-09-20 |
| 4344354 | Valve arrangement for controlling the stroke of a telescoping prop | Gottfried Siebenhofer, Rienhard Neuper, Alfred Zitz | 1982-08-17 |
| 4299517 | Mine roof supporting structure | Gottfried Siebenhofer, Alfred Zitz | 1981-11-10 |