The Trampoline Was Built From a Circus Idea, Named After a Spanish Word, and Used to Train Astronauts

US2370990 was granted to George P. Nissen and Larry Griswold on March 6, 1945. The title is "Tumbling Device." Everyone calls it a trampoline.

Nissen was a competitive gymnast and diver from Cedar Rapids, Iowa. As a teenager in the 1930s he watched circus trapeze artists finish their act by dropping into the safety net and bouncing — and noticed that the audience enjoyed the bounce, which was an accident, more than some of the choreography, which was not.

He built a prototype in his parents' garage with a friend and coach, Larry Griswold: a steel frame with a canvas bed slung inside it on coiled springs. The key structural idea is that the bed is not attached rigidly at all. Every spring in the perimeter stores and returns energy, which is what makes the rebound so high and so consistent.

The name

Nissen took the rig on tour through Mexico, performing with it, and picked up the Spanish word trampolín, meaning a diving board or springboard. He anglicized it to trampoline, and registered it as a trademark.

Like escalator and zipper before it, the trademark eventually lost its fight with common usage. The word is now simply the English name of the object.

What the military wanted with it

The trampoline's first serious institutional customer was not the playground. It was the armed forces.

During the Second World War, the United States Navy Flight School adopted trampolines for pilot and navigator training. The reason is precise: bouncing forces a person to continuously reorient themselves in the air, and a pilot needs exactly that skill — spatial awareness while the horizon is moving and the body is not where it expects to be.

The space program took the idea further. NASA used trampolines in astronaut training, because the rebounding flight phases offer brief periods of altered-gravity sensation and demand body control without a fixed reference frame.

The backyard

The trampoline became a competitive sport — it entered the Olympic Games in 2000 — and, more consequentially in sheer numbers, a backyard fixture.

That last transition brought a genuine problem that the patent could not anticipate. Backyard trampolines are the source of a large volume of emergency-room injuries every year, overwhelmingly from multiple children bouncing at once, where one child's landing launches another unpredictably. The industry's answer has been the safety enclosure net — now standard — plus springs covered by padding.

Nissen promoted his invention relentlessly for decades, including a famous publicity photograph of himself bouncing on a trampoline alongside a kangaroo in Central Park. He lived to ninety-six.

See the original

The full text and figures of US2370990 are on patents.us.