There are certain patent laws that establish if your patent will or will not be granted. These laws are explained below and are in accordance with 35 U.S.C. Section 102.
Your patent will not be granted if an invention was used or written by other people/inventors in the US. Your patent may be granted if the invention was practiced by other people/inventors in a foreign country but not if it was patented or described in a printed publication available to the public in the US or a foreign county before your invention. Your “invention” is what you explicitly claim in your patent claims of the patent application. And, “before your invention” is referring to the date at which you can prove it was invented, which may be earlier than your filing date, which you can prove with written records, if needed.
There is also a one-year grace period in the US. This means that if your invention was either patented or described in a printed publication anywhere in the world or if it was in public use or for sale in the US more than a year before you filed, then your patent will not be granted.
Your patent will not be granted if the invention has been abandoned. Actual abandonment under this law requires that the inventor actually intended to abandon the invention. You could probably assume that this would be hard to determine.
Your patent will not be granted if your invention was first patented or caused to be patented, or was the subject of an inventor’s certificate, by the applicant or his/her legal representatives in a foreign country prior to the date of the patent application in the US filed more than twelve months before the filing of the application in the US. This rule has four requirements in order for your patent to be barred. These include (1) if there has been a foreign application on your invention filed more than 12 months before the effective US filing date; (2) the same applicant must have filed the foreign application; (3) the foreign patent must be granted, but it does not need to be published, before the US filing date; and (4) this must involve the same invention. You do not have to worry if you do not file a foreign application that your patent will not be granted.
Your patent will not be granted if the invention was described in a patent application, published under — (1) an application for patent, published in accordance with 35 U.S.C. 122(b), by another filed in the United States before the invention by the applicant for patent or (2) a patent granted on an application for patent by another filed in the United States before the invention by the applicant for patent, except that an international application filed under the Patent Cooperation Treaty shall have the effects of an application filed in the United States only if the international application designated the United States and was published by the International Bureau in accordance with Article 21(2) of the Patent Cooperation Treaty in the English language. This refers to prior art in pending US patent applications that, when published or patented, suddenly becomes prior art as of their filing date. This could be very difficult to understand but in other words, your patent will be barred if there is a similar unpublished patent out there that you could not possibly know about. Patent applications are maintained in secret by the patent office for 18 months after their priority date. The priority date is the date of filing of the first application.
Your patent will not be granted if the invention derived from someone other than the inventor. You will also lose your right to the patent if someone else other than you, as the applicant, establishes that, before you invented your invention, that this someone else invented it.