Five Mechanical Engineering students from the University of Pennsylvania have developed quite a cutting edge bicycle for their senior project. The Alpha bike has been a year-long project to develop not only a bicycle that whose systems, mechanical and electrical, are completely integrated, but also create a bike that can be shifted from a freewheel to a fixed-gear setup on-the-fly. Geoff Johnson, Lucas Hartman, Katie Savarise, Evan Dvorak and Katie Rohacz worked with adviser Jonathan Fiene to bring the Alpha Bike from a concept to reality.
The most innovate feature of the Alpha Bike is the development of the Switchable Integrated Free-Fixed Transmission or “SWIFT Drive Technology”. The SWIFT Drive uses an electromechanical actuated clutch to allow the rider to switch between a free-wheeling and fixed mode with the flip of a lever. The key component in this system is the electromechanical clutch housed inside the bottom bracket area, which utilizes titanium, aluminum, stainless steel and bronze bushings to maximize strength and minimize weight. Along with the ability to switch between the free and fixed modes, the rider also has the use of 3-speeds incorporated inside the Sturmey-Archer rear hub which is controlled in a more traditional cable actuated fashion – of course integrated into the frame. The SWIFT Drive transmission is connected to the rear hub using a belt which is hidden inside the right-side chainstay. Continue reading Alpha Bike, a Proof in Concept