US Patent: 589,110
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Drilling Apparatus
Chain Drill
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Patentee:
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| Thomas L. Armstrong (exact or similar names) - Philadelphia, PA |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Apr. 06, 1897 |
| Granted: |
Aug. 31, 1897 |
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Russ Allen.
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Description: |
| Armstrong references Fifield's patent 555,442 and seeks to simplify and make the construction more efficient than Fifields's. Armstrong eliminates the spring used by Fifield and utilizes a ball-bearing to increase efficiency. |
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