ALEXANDRIA, Va., June 5 -- United States Patent no. 12,276,434, issued on April 15.
"Fixed plug for use in a process of forming an insulated register box" was invented by Sterling Kidd Combs (Magnolia, Texas).
According to the abstract* released by the U.S. Patent & Trademark Office: "A plug apparatus for sealing an interior of a duct for use in a process for forming an insulated register box has a frame, a shaft extending outwardly of the of the frame, and a plurality of layers of flexible material radiating outwardly of the shaft adjacent to an end of the shaft opposite the frame. The plurality of layers of flexible material are adapted to have an outer periphery bearing against an interior surface of the duct. Each layer of flexible ma...