Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| D338269 | Ergonometric stethoscope chestpiece | Joel R. Dufresne, Alan P. Dieken, Gerald E. Drake, legal representative Hostager | 1993-08-10 |
| D337381 | Ergonometric stethoscope chestpiece | Joel R. Dufresne, Alan P. Dieken, Gerald E. Drake, by Ray S. Hostager, legal representative | 1993-07-13 |
| 5204500 | Ergonometric stethoscope chestpiece | Joel R. Dufresne, Alan P. Dieken | 1993-04-20 |