When this idea is put into a working model or reduced to practice, invention occurs. The inventor is not required to file an application at that time. He may file at some later time and still obtain a patent, provided he did not create any statutory bars for himself or one else creates such a bar to obtaining a patent. See Statutory Bars, below. An invention is actually the combination of two steps.
Invention takes place on the date that the working model is functional.
If there is a contest between two inventors as to the first to invent, each of them will be called upon to produce evidence as to the date of their reduction to practice or invention. The government will also consider evidence of which person conceived of the idea first and was diligent in eventually reducing the idea to practice. This person may be deemed the first inventor and receive the right to the patent. This is one of the reasons that professional engineers and inventors maintain a daily log book of their efforts. Yes, there is.