What does a practicing physician turned inventor, envelopes, bicycles, and the Wright Bros have in common?
The envelope folding machine was invented by Doctor Russell Hawes who was a Worcester resident and a practicing MD. He was also mechanically gifted. In 1854 he quit his practice of medicine to design and build envelope machines that would run fast enough to keep up with the burgeoning need for envelopes generated by the skyrocketing demand for low cost machine-made greeting cards (vs high cost hand-made styles that had been hand folded for centuries). Dr. Hawes was handsomely rewarded for his efforts, and never again went back to the practice of medicine. As the sales of greeting cards soared, numerous small envelope manufacturing companies sprang up to fill the void between envelope demand and supply. Sheppard Envelope got its start in 1921 when two sons and a father name Sheppard designed and built their own folding machines to make envelopes specifically for the greeting card market (as well as other market segments).
Even the Wright brothers got into the act.
Orville and Wilbur were fascinated by envelope folding mechanisms too, and started making envelope folding machines prior to getting into the bicycle business, which literally got them off the gound and into powered flight. Although difficult to envision now, these seemingly diverse machines all capitalized on the identical principals of physics found in gears, cams, intermittent and reciprocating motion.