The helical spring was invented and developed by Richard James, a naval engineer, in the early 1940s. It was originally demonstrated at Gimbels department store in Philadelphia in November 1945. It sold out of its initial inventory (400 units) in 90 minutes! With that, a fad was born.
In 1952, the Slinky Dog was born. Other Slinky toys from the 50s include the Slinky train Loco, the Slinky worm Suzie and the Slinky Crazy Eyes, glasses that use Slinkys over the eyeholes and are attached to plastic eyes.
The Slinky was inducted into the National Toy Hall of Fame in 2000. In 2002, it became Pennsylvania’s official state toy. In the first 60 years, Slinky has sold 300 million units.