The other 24 semi-finalists in the Modern Marvels Invent Now Challenge are an eclectic bunch, ranging from bladder management devices to a product that stops you cutting your cat's nails too close to the quick...
The challenge is named in part for Modern Marvels, the History Channel's long-running series about US inventions.
4,300 submissions were entered.
"These semi-finalists represent the dreamers in America who have the tenacity to pursue their ideas in order to make an impact on the way all of us live-just like their predecessors, Ben Franklin and Thomas Edison," said Judy Klein-Frimer, co-creator of the Challenge for The History Channel.
The Modern Marvels Invent Now Challenge will showcase the inventions at an upcoming travelling expo. The exposition will travel to the California Science Center in Los Angeles (April 7-15th), the Museum of Science and Industry in Chicago (April 20-30th), the Museum of Science in Boston (May 5-14th) and culminate at Vanderbilt Hall in Grand Central Terminal in New York City (May 22-27th).
The winner along with the four other finalists will be announced in May. The Challenge winner will have his or her idea named the 2006 Modern Marvel of the Year and will receive a $25,000 grant.
The Shift trike-to-bike is a concept machine living mostly in the computer memory of academics at Purdue University. Last year it won the International Bicycle Design Competition at the Taipei trade show, often a kiss of death for any product hoping to be commercialised.
When it's a real product , Shift will help "children learn how to ride a bike by gradually teaching them how to balance on their own. With this concept, designers wanted to evolve beyond traditional training wheels, which only serve to prevent a bike from tipping. Shift provides more balance at lower speeds when stability is most critical (starting and stopping). As the child builds forward momentum, the bike's dual rear wheels shift inward, thus causing the balance to gradually shift from the bicycle to the child. Designers also wanted the bike's appearance to help build self-confidence. The look evokes nothing of the generally perceived childish training wheels."
Last year, Shift also won gold in the Design Explorations category of IDEA's awards, a competition sponsored and promoted by Business Week.