A pedal cycle crank arm 32 comprising a pedal spindle attachment part 321, a bottom bracket attachment part 322, a shaft 323 connecting the pedal spindle attachment part 321 to the bottom bracket attachment part 322, the length of the crank arm 32 being in a range of from 100 to 155 mm between the centrelines of the two respective attachment parts P-P,B-B. The outermost face of the pedal spindle attachment part 321 is coplanar with an outermost face of the bottom bracket attachment part 322 in a plane orthogonal to the centreline P-P of the pedal spindle attachment part 321 and the centreline B-B of the bottom bracket attachment part 322, and no part of the shaft 323 extends outwardly beyond the plane containing the outermost faces of the pedal spindle attachment part 321 and the bottom bracket attachment part 322. Such a crank arm 32 can increase the mechanical efficiency of a childs cycle significantly. Other aspects of the invention also provide a pedal cycle drivetrain comprising such a rank arm, and a pedal cycle frame of a size suitable to be ridden by children and mounted with such a crank arm.
Pedal cycle drivetrain component
2016-03-09
Patent
Elektronische Ressource
Englisch
IPC: | B62M RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES , Antrieb von Radfahrzeugen oder Schlitten durch den Fahrer |