Issued Patents All Time
Showing 76–78 of 78 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4483642 | Mine stopping and method of and jack for installing same | William R. Kennedy | 1984-11-20 |
| 4478535 | Mine stopping with man door and door frame assembly | William R. Kennedy | 1984-10-23 |
| 4373294 | Door for a mine stopping having knife-edge hinges | William R. Kennedy | 1983-02-15 |