| # | Country | Total Patents | |
|---|---|---|---|
| #1 | United States | 4 | |
| #2 | Canada | 3 | |
| #3 | Germany | 1 | |
| #4 | EPO (European Patent Office) | 1 | |
| #5 | Norway | 1 | |
| #6 | WIPO (World Intellectual Property Organization) | 1 |
| # | Industry | |
|---|---|---|
| #1 | Civil engineering |
| # | Technology | |
|---|---|---|
| #1 | Earth drilling |
| # | Name | Total Patents |
|---|---|---|
| #1 | Shirley Kirk R | 11 |
| Publication | Filing date | Title |
|---|---|---|
| US5038872A | Drill steering apparatus | |
| US4635736A | Drill steering apparatus | |
| US4394881A | Drill steering apparatus | |
| US3171503A | Expansible rotary drill bit | |
| CA872108A | Reverse circulation tool |