Patent Yard Sign in
Expired, full termArchiveSolo inventor

Revertive test system

US 1,437,357 A · Inventors: POWELL WINFRED T

USPTO PDF

Overview

The published document from the USPTO: abstract, claims, description and drawings. Open it full size

Read the whole patent

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.

Google PatentsUSPTO PDF

Why it's free to use

  • Granted November 28, 1922. A patent granted before 1976 lasted at most 17 years from grant, so its term ended by November 28, 1939.
  • We check US rights only. Old patents can still inspire new ones: improvements may be patentable.
FiledApril 9, 1919
GrantedNovember 28, 1922
Term endedNovember 28, 1939
Application number—
Classification (CPC)H04M15/08
Length9 pages

Timeline

Timeline From USPTO dates

1920192219241926192819301932193419361938Application filedApril 9, 1919Patent grantedNov 28, 1922Term endedNov 28, 1939

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

Everything on this page comes from the USPTO record linked above.