Showing 1–3 of 3 inventors
| Rank | Inventor | Primary Company | Patents |
|---|---|---|---|
| 1 | Zelda van Rooyen | — | 2 |
| 2 | Frederick Spencer Drake | — | 1 |
| 2 | Johannes Martinus Steenkamp | Unknown | 1 |
4 patents · 3 inventors
Ranked #73,472 of 111,555 cities Top 70%
Showing 1–3 of 3 inventors
| Rank | Inventor | Primary Company | Patents |
|---|---|---|---|
| 1 | Zelda van Rooyen | — | 2 |
| 2 | Frederick Spencer Drake | — | 1 |
| 2 | Johannes Martinus Steenkamp | Unknown | 1 |