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Hydropneumatic pumping system

US 2,247,238 A · Inventors: DOUGLAS JOHNSTON

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Listed from its USPTO record in Patent Yard's full-term archive. Its claims, description and drawings are in the USPTO PDF and on Google Patents, and the Claude kit works from them.

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Why it's free to use

  • Granted June 24, 1941. A patent granted before 1976 lasted at most 17 years from grant, so its term ended by June 24, 1958.
  • We check US rights only. Old patents can still inspire new ones: improvements may be patentable.
FiledApril 17, 1939
GrantedJune 24, 1941
Term endedJune 24, 1958
Application number—
Classification (CPC)F04B47/04 +1 more
Length15 pages

Timeline

Timeline From USPTO dates

1940194219441946194819501952195419561958Application filedApril 17, 1939Patent grantedJune 24, 1941Term endedJune 24, 1958

Sources & verification

Official USPTO records

Full published documentText and every drawing sheet as a PDF.USPTOFile historyStatus, office actions, notices, fee records and petitions.USPTO Patent CenterPatent Public Search recordSearchable full text and bibliographic data.USPTO

Cross-check elsewhere

Google PatentsFull text, worldwide family, citing patents and legal events.patents.google.comJustia PatentsFull text, claims and classification.patents.justia.comFreePatentsOnlineFull text and PDF.freepatentsonline.comEspacenetForeign family and legal status.European Patent Office

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