You can file a provisional patent application with a description and drawings to secure a priority date. Filed application for patent filed in the United States may claim the benefit of, or priority to, a prior application filed in the United States.What is a patent priority date? Priority date refers to the earliest filing date in a family of patent applications. Indeed, the best use of a provisional patent application is to establish priority rights as soon as you have an invention that can be patented. The priority date determines whether another patent filing or publicly available document qualifies as prior art against one's patent application. A PPA does not require discussions about the prior art, claims or an abstract. Filing date: Legal status: Expired - Lifetime. Patent filings based on US provisional patent applications. The priority date of a patent relates to the earliest filing date from within a family of patent applications.