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Counterbalance and support means for ceiling-mounted folding stairways

US 2,649,237 A · Inventors: WARREN BJORKLUND et al.

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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 August 18, 1953. A patent granted before 1976 lasted at most 17 years from grant, so its term ended by August 18, 1970.
  • We check US rights only. Old patents can still inspire new ones: improvements may be patentable.
FiledNovember 1, 1950
GrantedAugust 18, 1953
Term endedAugust 18, 1970
Application number—
Classification (CPC)E04F11/064
Length5 pages

Timeline

Timeline From USPTO dates

1951195319551957195919611963196519671969Application filedNov 1, 1950Patent grantedAug 18, 1953Term endedAug 18, 1970

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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

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