When we think of patents, usually a high-end tech product or process comes to our mind. But there are a whole lot of patents which are exceptionally simple, easy to make yet very useful. One such example is safety pin.
Safety pin was invented by Walter Hunt while twisting a single piece of wire that was coiled into a spring at one end. He added a clasp at the other end allowing the point of the pin to be safe from fingers, when secured. He invented safety pin to pay off a 15 $ debt that he owed to a friend. He made the prototype, designed several sketches & got the patent for safety pin on 10th April, 1849 (US Pat no. 6281). Afterwards he sold the patent only for $400 to W.R. Grace and Co to pay off the debt. Later, W.R. Grace and Co made millions of dollars in profits from his invention.
Today, safety pin has more than 100s of application including use in hospitals, ornaments, baby care products & sports etc.
To date there is no change in this cool product.
See more Patent info >http://www.google.com/patents/US6281