Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4838066 | Process and a device for the production of grooves on a wall of revolution | Jean Poullain | 1989-06-13 |
| 4799372 | Process for forming helical screw threads having a flank with zero or negative inclination | Jean Poullain | 1989-01-24 |