ALEXANDRIA, Va., June 16 -- United States Patent no. 12,304,631, issued on May 20, was assigned to United Parcel Service of America Inc. (Atlanta).

"Parcel delivery system and methods using rail system for unmanned aerial vehicles" was invented by Julio Gil (Veldhoven, Netherlands), Ethan Prescott Hill (Lexington, Ky.) and Jonathan Embry (Atlanta).

According to the abstract* released by the U.S. Patent & Trademark Office: "A multiple hoist system is used with an unmanned aerial vehicle (UAV) for delivering parcels. An example of the multiple hoist system comprises two or more hoists that are independently operable, meaning that a first hoist can lower or raise a first line independently of using a second hoist to raise or lower a second l...