Paulik v. Rizkalla
United States Court of Appeals for the Federal Circuit
760 F.2d 1270 (1985)
Paulik (plaintiff) reduced his invention to practice in 1970 but his employer, Monsanto, did not prioritize filing a patent application, resuming work only in early 1975 and ultimately filing in June 1975; Rizkalla (defendant) filed a competing application for the same invention with an effective date of March 1975, and the Patent Office's Board of Patent Interferences awarded Rizkalla priority, finding Paulik's four-year delay constituted suppression and concealment. Paulik appealed.
Whether an inventor who reduces an invention to practice but delays filing the patent application loses priority over a subsequent inventor if the first inventor resumes work on the invention before the second inventor enters the field.