Multiaxis Chainless Shaftless Compact Coastable Geared Bilateral Drive Mechanism and Novel Low Height Frame Set for Unicycles

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This drive mechanism does not use chaindrive or shaftdrive but has efficiency as chaindrive (in terms of gear teeth engagement) and requires less frequent maintenance. It also provides gear ratio.

Basic idea: Use internally toothed gear to rotate the hub of the wheel. It also uses part of rotation energy of the wheel for anti-tipping mechanism.

Drive mechanism, broadly speaking, is an epicyclic gear integrated to internally toothed slewing bearing such that internal gear of slewing bearing acts as outer ring gear of said epicyclic gear.

Outer ring of slewing bearing is attached to carrier plate via U-shaped pegs overbridging gear ring and attached at radially outward side to the bicycle frame. Gear ring may optionally on its outward side be attached to eared plate which in turn may be journalled at its center to the center of outward face of the carrier plate. Pedals are attached to outward side of the gear ring of the slewing bearing or the said eared plate. Eared plate protects rider clothing from cogs.

Three planetary gears (P1), (P2) and (P3) and a Sun gear (S) is journalled to carrier plate via ball bearings. U shaped pegs are attached to carrier plate in the space between the planet gears.

Planet gears are meshingly engaged to gear ring of slewing bearing. One planet gear (P1) is engaged with hub of the rear wheel. (P1) is coaxially attached to outer race of ratchet bearing mounted on the hub shell of the rear wheel. To facilitate syncing of pedals while coasting (P1) is attached at its center to axle of the rear wheel. (S), (P2) and (P3) are located on lower side of the center of wheel.

The drive mechanism is equipped with multi gear engagement system (MGES). According to (MGES) rear wheel on its faces are coaxally attached to inner gear rail which is externally toothed spur gear of smaller radius and outer rail which is internally toothed spur gear of larger radius. Sun gear (S) on its face is coaxially attached to anticlockwise oriented ratchet bearing which is meshing engaged to inner rail and planet gears (P2) and (P3) on its face is coaxially attached to clockwise oriented ratchet bearing which is meshingly engaged to outer rail. Ratchet bearings in (MGES) may be tipped with one ball bearing to prevent friction with wheel's face.
(MGES) (especially via sun gear) helps apply force on a larger area and reduce wobbling.

Various variations can be implemented to reduce the weight and cost.

(MGES) also works as anti-tipping mechanism (see figs). Novel frame set comprises seat tube, top tube head tube and steering mechanism. Fork of the wheel and seattube is in the form of inverted hook shape. Top tube connects head tube with upper end of seat tube. Steerer rod connecting connecting crown of the fork and handle is coaxially housed in the head tube via ball bearing. I have also invented reverse torque braking making which can be used in place of (MGES) as anti-tipping mechanism.


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  • Name:
    Ravi Shankar Gautam
  • Type of entry:
  • Profession:
  • Ravi Shankar is inspired by:
    Unicycles have generated lots of interest in the sport enthusiast both kids as well ass adults. But it is not safe in slope conditions. It also to tipp off and cause serious traumatic accidents. Part of the problem is height of the seat tube. Another problem is lack of steering mechanism. With improvement in safety measures unicycle can be in the main stream mode of transportation. Anti-tipping mechanism which do not use gyroscope will go a long way. Lack of efficient mechanism to obtain gear ratio in unicycles make its cumbersome.
  • Software used for this entry:
    3ds max
  • Patent status: