In general, a U.S. patent application should be filed as soon as possible after an invention is made.  A U.S. patent application should be filed before any non-confidential disclosure of the invention is made. If foreign patent protection is desired, a U.S. patent application must be filed before any non-confidential disclosure of the invention is made.  However, if one is not interested in foreign patents, there is a one-year grace period for filing a U.S. patent application on an invention measured from the time that the invention is first put on sale, put in public use, is described in a printed publication, or is disclosed in any manner non-confidentially, anywhere in the world, but only if the activity involves the inventor filing the patent application or someone who learned the invention from him (if done by anyone else, any of these activities precludes a valid patent issuing to the filer of the patent application).  If the U.S. patent application is not filed within the one-year grace period, it will not be possible to obtain a valid U.S. patent on the invention.

 A U.S. patent application can claim priority of a patent application filed in the U.S. or another country if filed within 12 months of the filing date of the earlier application (or up to 2 months later if the delay in filing was unintentional). 

Also, a U.S. patent application can claim priority of a prior U.S. patent application if the second application is filed while the first is still pending, and a priority claim is made within 16 months of filing of the first application or four months of filing of the second application, whichever is later. The priority claim can be made later upon payment of a surcharge.

Our patent attorneys can help you file a U.S. Patent Application which will help protect your rights. Contact us for assistance.