An electric power unit includes: an electric motor; a motor shaft disposed in the electric motor; an output shaft that outputs power of the electric power unit; a power transmission mechanism that is connected to the motor shaft and the output shaft and transmits power of the motor shaft to the output shaft; and a torsion damper disposed in the power transmission mechanism.

An electric power unit includes: an electric motor; a motor shaft disposed in the electric motor; an output shaft that outputs power of the electric power unit; a power transmission mechanism that is connected to the motor shaft and the output shaft and transmits power of the motor shaft to the output shaft; and a torsion damper disposed in the power transmission mechanism.

A ride-along vehicle may include a spring/chain guard that covers a spring and chain assembly and provides an attachment point for the spring. The guard may have a narrow portion that covers and helps retain the chain on a sprocket as well as a wider portion that covers the spring. In another embodiment, the spring can be connected to a fulcrum that has a chain retention pulley, gear, guide, or wheel that keeps the chain tight in loop to improve the pump-action operation of the vehicle. An improved pumper arm and steering mechanism may include a pivot joint that is provided by rods, pins, or bolts attached to opposite sides of the pumper arm. The universal joint between the steering arm and the pumper arm can be aligned with the center of the pivot point to prevent rocking of the steering arm as the pumper arm is actuated.

A ride-along vehicle may include a spring/chain guard that covers a spring and chain assembly and provides an attachment point for the spring. The guard may have a narrow portion that covers and helps retain the chain on a sprocket as well as a wider portion that covers the spring. In another embodiment, the spring can be connected to a fulcrum that has a chain retention pulley, gear, guide, or wheel that keeps the chain tight in loop to improve the pump-action operation of the vehicle. An improved pumper arm and steering mechanism may include a pivot joint that is provided by rods, pins, or bolts attached to opposite sides of the pumper arm. The universal joint between the steering arm and the pumper arm can be aligned with the center of the pivot point to prevent rocking of the steering arm as the pumper arm is actuated.

Disclosed is a rotation transmission mechanism including: an internal rotation member inserted by a crankshaft of a bicycle; and an external rotation member configured on the internal rotation member. The internal rotation member includes: an internal rotation member body. The external rotation member includes: a circular ring part configured at an outer side of the outer circumferential convex parts; and inner circumferential convex parts protruding to an inner circumferential side of the circular ring part and configured alternately with the outer circumferential convex parts. Elastic deformation parts are configured between the outer circumferential convex parts and the inner circumferential convex parts on a rotation direction side of the advancing outer circumferential convex parts. The outer circumferential convex parts are formed in such a manner that a surface on the rotation direction side is greater than a surface on an opposite side of the rotation direction.

Disclosed is a rotation transmission mechanism including: an internal rotation member inserted by a crankshaft of a bicycle; and an external rotation member configured on the internal rotation member. The internal rotation member includes: an internal rotation member body. The external rotation member includes: a circular ring part configured at an outer side of the outer circumferential convex parts; and inner circumferential convex parts protruding to an inner circumferential side of the circular ring part and configured alternately with the outer circumferential convex parts. Elastic deformation parts are configured between the outer circumferential convex parts and the inner circumferential convex parts on a rotation direction side of the advancing outer circumferential convex parts. The outer circumferential convex parts are formed in such a manner that a surface on the rotation direction side is greater than a surface on an opposite side of the rotation direction.

A cycle crank assembly includes a crank spindle and a drivetrain connector configured to translate rotation of the crank spindle into rotation of a wheel. A crank arm includes a pedal interface configured to receive a pedal spindle of a cycle pedal. A slip connection is configured to allow the crank arm to rotate about the crank spindle. A resiliently deformable member is connected to the crank spindle and the crank arm proximate to the pedal interface. The resiliently deformable member translates rotation of the crank arm into rotation of the crank spindle. The resiliently deformable member deforms under load to store pedal energy provided by a rider to the cycle pedal and returns at least a portion of the pedal energy when not under load in a direction of the rotation.

A wheel rotated by a load applied to an axle remaining stationary at an eccentric position is disclosed. The present invention comprises: the wheel configured such that the outer periphery of an inner rim of the wheel assembled to a wheel hub provided at the axle to which the load is applied applies pressure to a plurality of compressive force elastic bodies provided at the inner periphery of an outer rim of the wheel; and a control roller for pushing the outer rim of the wheel at a gap of a predetermined range such that the axle provided at the wheel hub always remains stationary at the eccentric position of the wheel.

A wheel rotated by a load applied to an axle remaining stationary at an eccentric position is disclosed. The present invention comprises: the wheel configured such that the outer periphery of an inner rim of the wheel assembled to a wheel hub provided at the axle to which the load is applied applies pressure to a plurality of compressive force elastic bodies provided at the inner periphery of an outer rim of the wheel; and a control roller for pushing the outer rim of the wheel at a gap of a predetermined range such that the axle provided at the wheel hub always remains stationary at the eccentric position of the wheel.

A bicycle crank transmission apparatus includes: a hollow shaft member; a base plate coupled to the shaft member on one side and installed securely on a bottom bracket featuring a spindle on the other side; a chainring housing coupled to the shaft member in a way that allows its rotation and having a ring gear installed securely inside; a reduction gear unit arranged in the middle of the ring gear; a directly-coupled ratchet unit installed on the ring gear; a crank cover where a coupling shaft coupled to the spindle is perpendicularly provided in the center and where clutch ratchet teeth, which are engaged with the directly-coupled ratchet unit, and directly-coupled ratchet teeth are vertically stacked on the internal wall surface; and a sun gear installed on the coupling shaft in such a way that it only rotates in clockwise direction and partially engaged with the reduction gear unit.