What product did Walter Hunt invent in 1849 to pay off a fifteen dollar debt?

In 1849, the resourceful American inventor Walter Hunt found himself facing a modest but pressing financial predicament: a fifteen-dollar debt. Rather than simply borrowing the money, Hunt, a prolific tinkerer with a knack for practical solutions, set out to invent something that would quickly generate the necessary funds. His ingenious solution, conceived from a single piece of brass wire twisted into a spring-loaded clasp, was the safety pin.

Hunt's design was a significant improvement over earlier, more basic pins, which often left sharp points exposed and could easily come undone. His innovative addition of a spring mechanism and a protective clasp that covered the pin's point made it safe and reliable for securing fabric. This simple yet brilliant invention was patented on April 10, 1849.

Despite the immense success and ubiquitous nature the safety pin would later achieve, Hunt himself did not reap substantial financial rewards from it. He sold the patent rights for his "dress pin," as he initially called it, for a mere $400 to W.R. Grace and Company. This sum allowed him to pay off his $15 debt with plenty to spare, but it meant he missed out on the millions of dollars in profits that subsequent opportunistic businessmen would earn from his creation.

Hunt was known for inventing many other useful items throughout his life, including an early sewing machine, a knife sharpener, and a fountain pen, though he often sold his patent rights for low prices. The safety pin, born out of a small debt, remains a testament to his inventive spirit and continues to be an indispensable item in households worldwide, used for everything from fastening clothing to securing cloth diapers.