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Breaking the chain

Engineering students aim to redesign the bicycle by using hydraulic power

Students at nine universities across the country are putting a new spin on an old idea by taking part in a competition sponsored by Parker Hannifin Corp., Cleveland, to design a human-and hydraulicpowered bicycle, which will eliminate the use of chains.

The bikes cannot have a direct connection between the chainwheel (the sprocket with the pedals connected to it) and the freewheel cogs (the smaller sprocket on the drive wheel). Instead, the pedals can be connected to a hydraulic pump and a hydraulic motor connected to the wheels to propel the bike.

"With this project, we are trying to increase energy recovery in the bicycle," said Larry Schrader Jr., Global Motion and Control Training Manager at Parker. To do this, some schools have chosen to include energy recovery in the form of an accumulator. When braking or going downhill, energy is stored in the accumulator, and then discharged later, making uphill travel easier.

"The current design shows that the bike functions under extreme stress and adverse conditions," Shrader said. "It's the world's most popular vehicle."

Huge potential impact

With more than 14 billion bicycles worldwide, a market of $4.2 billion, and an aftermarket of $1 billion, Parker views the bicycle as a market ripe for change. The end goal, said Schrader, will be to create a demand for hydraulics that can be translated to other applications — such as the marine industry — where manual cranks and gears are currently implemented. "This will expose a lot of engineering students to motion control and hydraulics," Schrader said.

The competition evolved from a partnership that Parker has with 10 universities nationwide. Each year, the company hosts a two-day meeting with the universities and presents students with a challenge to bring real-life design opportunities into the classroom. The project has been incorporated into the students' curriculum.

"We wanted to take a group of students, give them a problem, and have them solve the problem. Our customers want problemsolvers who will work together as a team and solve the problem," Schrader said. "We're trying to give the students a real-world design experience."

The student teams will travel to Cleveland on August 8 and 9, where they will run their bikes on a course through the Cleveland Metroparks' Brecksville Reservation. The 12-mile course includes elevation changes and winding curves. Each team has a maximum of five student members and is assisted by a Parker engineer.

Over the past nine months, the teams developed ideas and designs, presented these designs to Parker, and began building their inventions. The rules are lenient, allowing for unique designs — for example, the bikes can have as many wheels as the teams want — but certain rules do apply.

Ground rules

The bikes must use biodegradable fluid, rear view mirrors, and multiple, fully-active independent brakes that provide failsafe braking. The bike cannot be modified in such a way that a rider is unable to enter, exit, start, and stop unassisted. Bikes must be human-powered and cannot use internal combustion engines or electric motors.

Of the nine schools entering, eight are using hydraulics to power their bike; one school has chosen to use pneumatic power. Parker provided accumulators for each team's design.

Students will be judged on their renderings and design plans, as well as the bike's operation, speed, and ability to complete the course. All students on the overall winning team receive a $2,000 scholarship. Category awards will also be given to the schools' engineering departments, including awards for fastest course time, lowest overall cost, manufacturability, reliability and safety, marketability, highest total score, ingenuity and novelty, best workmanship, and best paper.

Participating teams hail from Cleveland State University, University of Akron, Murray State University, University of Cincinnati, University of Illinois, Cal-Poly - San Luis Obispo, University of California Irvine, Western Michigan University, and Purdue University.