|
US2954131A
|
|
Oil well hoist
|
|
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Hydraulically operated pumping apparatus
|
|
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Telescopic derrick and locking means therefor
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Cable winding clamping apparatus
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Process and apparatus for quenching tubular metal articles
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Hydraulic braking apparatus
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Hydraulic servo control apparatus
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GB703342A
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Improvements relating to pumping units of the reciprocating type
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Pumping unit
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Counterweight
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Automatic length-controlling apparatus
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