A utility patent is a property right that the United States government grants in exchange for putting a new invention into the public domain.
As a reward for inventions and to encourage their disclosure, the United States offers a ... monopoly to an inventor who refrains from keeping his invention a trade secret. But the quid pro quo is disclosure of a process or device in sufficient detail to enable one skilled in the art to practice the invention once the period of the monopoly has expired.
— Universal Oil Co. v. Globe Co., 322 US 471, 484 (S. Ct. 1944).
A patent grants the right to exclude others from practicing an invention.
Every patent shall … grant to the patentee, his heirs or assigns, … the right to exclude others from making, using, offering for sale, or selling the invention throughout the United States or importing the invention into the United States, and, if the invention is a process, of the right to exclude others from using, offering for sale or selling throughout the United States, or importing into the United States, products made by that process, referring to the specification for the particulars thereof.
— 35 U.S. Code § 154 (a) (1)
A patent is not an affirmative right to practice an invention. Sometimes a patentee is blocked from practicing their invention for a number of reasons including blocking patent rights, fixed costs preventing entry into a marketplace, or producers that are unwilling to license at any price.
The unrestricted sale of a patented article exhausts the patent holder’s right to exclude with respect to that article. For example, the doctrine of patent exhaustion protects a buyer’s right to repair a patented item after an initial unrestricted purchase.
In order to call the monopoly, conferred by the patent grant, into play for a second time, it must, indeed, be a second creation of the patented entity, as, for example, in Cotton-Tie Co. v. Simmons, supra. Mere replacement of individual unpatented parts, one at a time, whether of the same part repeatedly or different parts successively, is no more than the lawful right of the owner to repair his property.
— Aro Mfg. Co. v. Convertible Top Replacement Co., 365 US 336, 346 (S. Ct. 1961).
A patent holder does not hold unlimited authority to leverage their patent for financial gain. The law prohibits practices such as licensing an invalid patent or tying unrelated products to a patent license in an anticompetitive manner.