Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5148645 | Use of fibrous mat-faced gypsum board in shaft wall assemblies and improved fire resistant board | Charles W. Lehnert, Brian G. Randall, George F. Fowler | 1992-09-22 |
| 4748771 | Fire door | Charles W. Lehnert, James R. Van Dyke | 1988-06-07 |