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US1877495A
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Bearing
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US1855337A
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Drilling cable protecting means
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US1812471A
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Guide-bearing
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US1730995A
|
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Derrick-frame construction
|
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US1569000A
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Weight for sinking well casings
|
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US1710471A
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Filter for well screens
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US1626393A
|
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Frame structure
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US1507580A
|
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Well screen
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US1518390A
|
|
Well and method of sinking
|
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US1488662A
|
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Method of sinking, cleaning, and removing well screens
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US1431872A
|
|
Well screen
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US1342986A
|
|
Well-screen
|
|
US1189428A
|
|
Means for protecting drilling-ropes against wear.
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