Description
Stethoscope
This patent is the first USA patent on the stethoscope.
The first commercially successful stethoscope was the Cammann. He never filed patents on his inventions because he wanted it to be readily available to medical practitioners.
The first USA patent on the stethoscope was by Ford. This patent was for a concealed noiseless spring that eliminated vibrations due to the breath of the examiner which lead to confusion of readings.