| # | Country | Total Patents | |
|---|---|---|---|
| #1 | France | 19 | |
| #2 | Brazil | 10 | |
| #3 | South Africa | 10 | |
| #4 | Argentina | 3 | |
| #5 | United Kingdom | 2 | |
| #6 | Israel | 2 | |
| #7 | New Zealand | 2 | |
| #8 | United States | 2 | |
| #9 | Canada | 1 | |
| #10 | Italy | 1 | |
| #11 | Sweden | 1 |
| # | Industry | |
|---|---|---|
| #1 | Machines | |
| #2 | Machine tools |
| # | Technology | |
|---|---|---|
| #1 | Turning | |
| #2 | Unspecified technologies | |
| #3 | Unspecified technologies | |
| #4 | Workshop equipment |
| # | Name | Total Patents |
|---|---|---|
| #1 | Hougen E | 26 |
| #2 | Hougen E D | 1 |
| Publication | Filing date | Title |
|---|---|---|
| ZA8204595B | Annular hole cutter | |
| US3825362A | Arbor for an annular hole cutter | |
| CA928107A | Hole saw | |
| US3765789A | Annular hole cutter |