Bicycle Equipped with Slotted Lever Quick Return Mechanism

Abstract

The low-impact nature of cycling does not exclude cyclists from musculoskeletal problems that arise due to prolonged and incorrect postural adaptations combined with repetitive limb movements. Hence efforts are made to reduce the musculoskeletal problems by replacing the conventional chain and sprocket mechanism of the bicycle with a slotted lever quick return mechanism (SLQRM), which eliminates the 360° crank and ankle rotation by allowing nearly vertical up and down motion of the legs, which reduces the flexion at the knees. The reduced knee flexion is thus expected to reduce the risk of pain at the knee’s patellofemoral joint (PFJ), sciatic nerve blockage, and knee swelling. This mechanism is more efficient than the conventional chain and sprocket mechanism because the levers are longer than cranks and pedals move up and down, so the rider puts less effort into generating more torque. Additionally, the gravity force is useful for riders to help move down the lever crank. Preliminary analysis of various assemblies with a load of 100 kg on a single pedal shows that the maximum stress of 220 MPa and the maximum strain of 0.000842 were developed at the gear and curved strip assembly; the maximum displacement of 3.22 mm and minimum FOS of 1.95 were seen at the gear and pedal crank arm assembly, which are considered satisfactory.