In 1856 Mr. Zimmermann was issued a patent for this invention from the United States Patent & Trademark Office (USPTO). There are 4 documents included with this patent The drawing specification sheet of the patent has been reproduced from original USPTO documents and printed onto parchment paper. This print is sized and ready to install into an 8" x 10" frame. The additional sheets included are printed on 5.50" x 8.50" parchment paper. These accompanying documents describe the scope of this invention in formal terms. The following is an actual excerpt from the patent…

       " Be it known that I, Charles Moritz Zimmermann, of the city of Philadelphia and the State of Pennsylvania, have invented certain new and useful Improvements in Accordions, Concertinas, and other Similar Instruments; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawing and to the figures and letters of reference marked thereon. My invention relates to improvements in that class of musical instruments, in which sound is produced by air forced by means of bellows against a series of reeds, such as accordions, concertinas, and melodeons and consists in arranging the valves of the above mentioned instruments in connection with sliding rollers acted upon by the keys, and regulated by stops, in such a manner that by pressing the stops the said sliding rollers may be passed from one valve to another or brought to open two valves together thereby enabling the operator by pressing one key to produce a variety of different notes"…