The U.S. was invented by Chauncey Wing (1847 - 1927) of Greenfield, MA. and it was produced by Wing's company, C. Wing Machine Works, the typewriter arm of the Chauncey Wing Machine Co. The business was located at 78 Pierce Street in Greenfield since 1884 and in 1887 it was listed Greenfield's directory of typewriter manufacturers.
Adler's book, Antique Typewriters, From Creed to QWERTY, describes this typewriter as "...an indicator machine using type on the teeth of a linear comb, inking by roller." The woodcut at the top of this page also shows a grate base and a pair of acorn-shaped escapement levers. Also, note the two small oil cans tucked away on the right side of the typewriter.
1887 - 1889
C. Wing Machine Works
Greenfield, MA, US
It's called the U.S. Typewriter. It was patented in 1877 (patent no.363,570). As of yet, not a single one of these has been found nor is there any indication that any serious manufacturing of it took place. That doesn't mean that there weren't a few produced which are now collecting dust in an attic somewhere just waiting to be found.
You may be asking, "Why are there acorn-shaped levers on the typewriter?" They may have been a reference to the progressivist sentiment of the Industrial Era, to the idea that technology would solve all the world's problems. The phrase "Mighty oaks from little acorns grow" was very popular at the time and so the acorn became the adopted symbol.
Chauncey Wing's typewriter was really just a blip in his otherwise incredible manufacturing career. His company had survived over 100 years thanks to the success of another one of his inventions, the Wing Mailer, a label applicator. When his two sons took over the family business in 1918, they fittingly renamed it to Chauncey Wing's Sons. In 1922 the company produced about two dozen racing cars called the Wing Special. Until recently it wasn't even known if any of the racers survived until one bubbled-up on Ebay. If the Wing Special managed to survive then why not the U.S. typewriter, right?