Sometimes there are two or more applications for patent claiming the same invention a different inventors. The PTO board of Patent Appeals and Interferences decides the question of priority of invention, in other words, who is the first inventor among the different parties. US federal courts can review the board’s decision.
Scope of an Issue to United States Patent
The United States Patent and Trademark Office only has jurisdiction over the United States. That means if you receive a successful patent from the United States patent trademark office he will only be able to exclude others from the use of that invention in the United States. If you wish for patent protection in other countries, you must file patent applications in the individual countries or proceed with the Patent Cooperation Treaty as described in https://openlab.citytech.cuny.edu/rowland/where-to-begin-when-you-have-a-new-invention-idea/.
Relevant Time Periods
Inventors must be extremely careful about their activities prior to applying for a patent. You have a one year deadline for filing an application from any of the following events: placing the invention on sale, publishing a description of the invention, offering a detailed description of the invention at a public meeting, or placing the invention into the hands of the public.
If you run past the one year deadline, you will lose your chance to file a patent application for that invention. You can find more tips about patenting process at https://blogs.ubc.ca/inventhelpreviews/ too.