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Newswise — With a frame that's lighter, more aerodynamic and less breakable than many top-of the-line counterparts, a new bicycle created by a team of Brigham Young University engineers may soon change the face of cycling. A second team has created the "Y-Flex," a weight simulation fitness machine coming soon to a home gym near you.
Made from carbon fiber intertwined with Kevlar string, the bike's frame employs civil engineering professor David W. Jensen's IsoTruss -- a cage-like, open tubular lattice that optimizes the inherent strength of reinforcing pyramids and triangles.
"The team's goal was to shrink the IsoTruss structure, which has been proven to work well for large-scale applications, from between 5 to 18 inches to about 1 inch in diameter," said Jensen. "Everybody involved has done a great job of accomplishing just that."
Also built by BYU engineers, the Y-Flex prototype home fitness machine sports two rows of adjustable, bendable fiberglass poles with guides that simulate the feel of free-weights. The pole-guide systems are "compliant mechanisms," a special class of devices that transfer motion, force or energy without the use of movable joints à la fingernail clippers, backpack latches and paperclips.
The Y-flex uses patent-pending technology that provides a weight-stack-free workout that feels more like weights than other resistance-based workout machines do, say engineering professors Larry Howell and Spencer Magleby.
"The advantage to using compliant mechanisms in the machine is that it will cost less and be simpler for a manufacturer to make and assemble," says Howell, who literally wrote the book on compliant mechanisms as well as more than 100 scholarly papers on the topic. "Using the technology to reduce the number of joints also increases performance " the machine is more precise and reliable and there is reduced wear, weight and maintenance involved."
Background -- IsoTruss Bicycle
In 2002, the IsoTruss technology used to build the mountain bike was licensed to Brigham City company IsoTruss Structures Inc., which uses it to build structures as strong as steel without the weight, like meteorological instrumentation towers and self-supporting utility poles.
As IsoTruss Structures works to market the technology, BYU researchers continue to test and develop new ways of applying it.
Tyler Evans, a senior in manufacturing engineering technology who worked on turning the IsoTruss into a bicycle, says the new geometry of the BYU bike frame generates double-takes on the mountainside, but is responsible for a cycle that's as light, stronger and more aerodynamic than some of the best traditional carbon-fiber mountain bikes on the market.
"This frame weighs in at 3 1â„4 pounds, and we're confident the next one will be less than 3 pounds," says Tyler, also a mountain bike enthusiast. "That's a big deal in the cycling world."
Bigger yet, the BYU engineers are working to reverse the reality of "light bike, heavy price" by streamlining their manufacturing process to make ultra-light racers -- normally priced in the "$5,000 and over" range -- more affordable for cyclists everywhere.
Background -- Y-Flex Fitness Machine
The Y-Flex resembles other freestanding weight machines common to gyms, garages and basements " a bench connected to a tower with a cord and pulley system that allows users to select amounts of "weight" and pull or push that weight using a bar or handle. Instead of actual weights, the Y-Flex uses resistance, similar to what happens with fitness machines like Nautilus' Bowflex, which makes it light and easy to move.
"The biggest difference between those machines and the Y-Flex is that they provide resistance like an uncoiled spring does " at first it's easy to push, and then it gets harder at the end when the coil is compressed," says Howell. "The compliant mechanism technology incorporated into the Y-Flex simulates the feel of constant weight from the start of an exercise to its end. It's more like what you experience with free-weights."
Howell, Magleby and numerous mechanical engineering students have also incorporated compliant mechanisms into other devices like bicycle brakes and clutches on lawnmowers and chainsaws.
Now that the team of BYU engineers has proven that compliant mechanism technology works in a fitness application, members are interested in seeing a company come along and adapt the Y-Flex's core technology to its particular needs, says Magleby.
"The Y-Flex is a successful prototype and we feel the technology it showcases represents a wonderful opportunity for an existing company or an entrepreneur to get an innovative piece of fitness equipment out there for the public to enjoy."
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