Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4685094 | Lateral compliance device for geophone springs | Arend L. Hagedoorn | 1987-08-04 |
| 4623991 | Delta-shaped geophone spring | — | 1986-11-18 |
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4685094 | Lateral compliance device for geophone springs | Arend L. Hagedoorn | 1987-08-04 |
| 4623991 | Delta-shaped geophone spring | — | 1986-11-18 |