Patent attributes
A mechanism includes a housing, a transmission axle arranged at a center of the housing, an internally toothed ring track fixed to an inner circumference of the housing, and a coaxial gear set arranged between the transmission axle and the internally toothed ring track. The coaxial gear set includes a sun gear, a planetary gear set, and an output member. The planetary gear set includes a first carrier frame and a second carrier frame rotatably arranged at two ends of the sun gear. Multiple planetary gears are rotatably arranged between the first and second carrier frames and around the sun gear. Each of the planetary gears is in meshing engagement with the output member. The coaxial gear set is made in a modularized form for subsequent assembly in an optional manner, so as to provide an efficacy of easing assembling and servicing operations.