Whether an inventor’s “four-year delay from reduction to practice to his filing date [constitutes] prima facie suppression or concealment under the first clause of section 102(g), that since Paulik had reduced the invention to practice in 1971 and 1972 he was barred by the second clause of section 102(g) from proving reasonable diligence leading to his 1975 filing, and that in any event the intervening activities were insufficient to excuse the delay.”
“We hold that such resumed activity must be considered as evidence of priority of invention. Should Paulik demonstrate that he had renewed activity on the invention and that he proceeded diligently to filing his patent application, starting before the earliest date to which Rizkalla is entitled–all in accordance with established principles of interference practice–we hold that Paulik is not prejudiced by the fact that he had reduced the invention to practice some years earlier.”
