Issued Patents All Time
Showing 51–75 of 78 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6256946 | Adjustable stairway for use with an overcast in a mine | William R. Kennedy | 2001-07-10 |
| 6220785 | Mine stopping, method of constructing same and panels thereof | William R. Kennedy | 2001-04-24 |
| 6164871 | Mine stopping having a swinging door | William R. Kennedy | 2000-12-26 |
| RE36853 | Mine door system | William R. Kennedy | 2000-09-05 |
| 6032986 | Door system for a mine stopping | William R. Kennedy | 2000-03-07 |
| 5812741 | Serial sequencers connected in parallel | William R. Kennedy | 1998-09-22 |
| 5795367 | Method of and apparatus for reducing sulfur in combustion gases | William R. Kennedy | 1998-08-18 |
| 5466187 | Mine ventilation structure | William R. Kennedy | 1995-11-14 |
| 5412916 | Structure having quick-connect components | William R. Kennedy | 1995-05-09 |
| 5240349 | Power mine door system | William R. Kennedy | 1993-08-31 |
| 5222838 | Power mine door system | William R. Kennedy | 1993-06-29 |
| RE34220 | Contractible mine stopping and contractible block member for use therein | William R. Kennedy | 1993-04-13 |
| 5168667 | Door system for a mine stopping | William R. Kennedy | 1992-12-08 |
| 5167474 | Form for making a permanent concrete mine stopping | William R. Kennedy | 1992-12-01 |
| RE34053 | Mine door system | William R. Kennedy | 1992-09-01 |
| 4915540 | Contractible mine stopping and contractible block member for use therein | William R. Kennedy | 1990-04-10 |
| 4911577 | Mine door system | William R. Kennedy | 1990-03-27 |
| 4820081 | Head seal for a mine stopping | William R. Kennedy | 1989-04-11 |
| RE32871 | Mine stopping | William R. Kennedy | 1989-02-21 |
| RE32675 | Mine stopping and method of and jack for installing same | William R. Kennedy | 1988-05-24 |
| 4695035 | Jack for installing a mine stopping | William R. Kennedy | 1987-09-22 |
| 4636527 | Method for the preparation of styrene polymer foam and foam prepared thereby | Kyung W. Suh | 1987-01-13 |
| 4547094 | Mine stopping | William R. Kennedy | 1985-10-15 |
| 4523406 | Door frame and door assembly for a mine stopping | William R. Kennedy | 1985-06-18 |
| 4484837 | Mine stopping lap-over panel clamp | William R. Kennedy | 1984-11-27 |