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G-Drill AB Patents |
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Assignee: G-Drill AB
Address: Stockholm, SE
No. of patents: 1
Patents:
| Patent Number |
Title Of Patent |
Date Issued |
| 5715897 |
In-hole rock drilling machine with a hydraulic impact motor |
February 10, 1998 |
| An in-hole rock drilling machine has a hydraulic impact motor within a housing. The hydraulic impact motor has a spool valve contained within a valve housing. The spool valve has two operating positions to alternately pressurize and depressurize a drive chamber to reciprocate a hammer. T |
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