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SENIOR DESIGN TEAM 09
HANSEN: SPRAG CLUTCH ADDITION TO RECIPROCATING LEVER TRANSMISSION
DELIVERABLES -
SENIOR DESIGN TEAM 09
HANSCycle
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SENIOR DESIGN TEAM 09
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Gordon Hansen is currently studying bicycle infrastructure improvements and intergenerational neighborhood planning, following four decades of private and public sector work in urban planning and design. US Patent 8,763,481 (https://www.google.com/patents/US8763481) was issued to Gordon for a Reciprocating Lever Transmission (RLT) intended to serve as an alternative to electric assisted bicycles, and to serve as a foundation for a new class of bicycles. Gordon previously sponsored Team 20 in 2016 and Team 08 in 2017.
Iain Marsh is a senior at Florida State University pursuing a B.A. in Mechanical Engineering. He is from Redington Beach, FL and has an interest in thermal fluids and vehicle design. He hopes to design fuel-efficient vehicles utilizing the knowledge acquired at the FAMU-FSU College of Engineering. After graduation he will commission as a 2nd Lieutenant in the United States Marine Corps.
Angela was an International Baccheleureatte student and graduated from Ridgeview High School, Orange Park, Florida in 2014. She is currently pursuing a Bachelors of Science in Mechanical Engineering and is enrolled at the FAMU/FSU College of Engineering. She plans on graduating in the fall of 2018.
Daniel Dudley is a senior in mechanical engineering at FSU. Daniel was born and raised in Perry, Florida and spent many of his hours as a kid playing baseball, soccer, weightlifting, and hunting. After graduating in the Spring of 2018, he would like to pursue a career in the aerospace industry.
Grant Parker is a senior mechanical engineering student at The Florida State University. Grant has a strong liking for math and science, and has always been interested in how things work, so the choice to major in mechanical engineering was easy. After graduating Grant hopes to find employment as a mechanical engineer in the Southeast.
Evan is a senior Mechanical Engineering student from Perry, Fl. He will graduate in the Spring of 2018 with a B.S. in Mechanical Engineering from Florida State University. He has an interest in the thermal fluids science field and would like to pursue a career in that field following graduation.
Due to the increasing popularity of bicycles as the primary mode of transportation for flatland cities such as Amsterdam and Copenhagen, it is believed that this trend will grow if a bicycle design has a drive train that delivers more power output. Traditional bicycles have a drive train consisting of pedal crank arms rotating 360 degrees connected to large chain rings. The sponsor’s patent for the Reciprocating Lever Transmission, or RLT, have a reciprocating motion. This means that as a downward force is applied to one crank arm, the return mechanism within the RLT causes the other crank arm to return in an upwards motion.
The new RLT design features a sprag clutch is added to transmit forces from the crank arms to the drive shaft. The sprag clutch chosen is the GMN FE433M. This was chosen for its size and torque capacity. The RLT design has is designed to have 4 sprag clutches, 2 per side of the RLT.
14 inch crank arms with a tapered profile replaces the previous design of 10.5 inches. Longer crank arms creates more torque and result in more power output.
The custom made bevel hubs are made of two components. They were modeled around the SUS303 stainless steel bevel gears. Attached is extruding cylinder which acts as an outer race to the sprag clutches. The end of the bevel hub has splines extruding to connect to the crank arms and held together with an e-clip.
A sprag clutch consists of an inner and outer race with wedges known as sprags between them which transmits torque from the driving race to the driven race. The sprags permit rotation in one direction and back stopping in the other. Sprag clutches have many applications including motorcycles and helicoptors. They are also used in rear wheel hubs for various types of bicycles. The addition of a sprag clutch would provide the RLT with a greater torque transmission relative to the size and weight.
