US 4,666,172 AGranted

Multiple speed planetary transmission for pedal-powered vehicles

OwnerDirck T. Hartmanninventor

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Abstract

A multiple speed planetary transmission which mounts inside the wheel hub of the driving wheel or wheels of a bicycle or the like, concentric with the pedal drive shaft. The transmission includes a gear case mounted on ball bearings on the pedal drive shaft, a cylindrical extension of the gear case being clamped to the bicycle frame on one side. Multiple sets of different size planet gears are rotatably mounted on a planet gear carrier fitting driven by the pedal drive shaft. A ring gear is mounted in tracks in the gear case with its axial position adjustable so that it can be positioned to mesh with any one of multiple sets of different size planet gears. A sun gear assembly has its multiple gears in constant mesh, respectively, with multiple sets of planet gears. A conventional free-wheel ratchet mechanism drives the wheel hub from the sun gear assembly, and a second conventional free-wheel ratchet mechanism drives the sun gear assembly from the drive shaft to provide a direct drive option. This compact, low maintenance transmission permits the wheelbase for a tandem bicycle using it to be the same as the wheelbase for a conventional single bicycle.

Claims6

Dependent claims

In a pedal-powered vehicle including a pedal drive shaft, a frame, and a driving wheel having a hub concentric with the axis of rotation of said drive shaft, an improved multiple speed, chainless planetary transmission mounted within said hub and in concentric relation with the axis of rotation of said hub and comprising:

a gear case fixed to said frame and including axially extending guide tracks;
a planet gear carrier mounted to said drive shaft for rotation therewith;
multiple sets of different size planet gears rotatably carried by said carrier;
an internally toothed ring gear supported upon said guide tracks and axially movable along said guide tracks for selected meshing with any one of said multiple sets of said planet gears;
sun gear means having a plurality of externally toothed sun gears meshed with said multiple sets of said planet gears, respectively, and supported for concentric rotation about said drive shaft;
first free-wheel ratchet means coupled between said hub and said sun gear means for driving said hub;
second free-wheel ratchet means coupled between said pedal drive shaft and said sun gear means for driving said sun gear means;
and
ring gear positioning means operable for axially moving said ring gear along said guide tracks whereby said hub is adapted to be driven at a selected rate of rotation depending upon the particular set of said multiple sets of said planet gears engaged by said ring gear.

6 more elements

a gear case located within said hub and including an end having a cylindrical extension fixed to said frame, said gear case including axially extending guide tracks;
a planet gear carrier fixed to said drive shaft for rotation therewith;
multiple sets of different size planet gears rotatably carried by said carrier;
an internally toothed ring gear supported upon said guide tracks and axially movable along said guide tracks for selected meshing with any one of said multiple sets of said planet gears;
sun gear means having multiple externally toothed sun gears in constant mesh with said multiple sets of said planet gears, respectively, and supported for concentric rotation about said drive shaft;
first free-wheel ratchet means coupled between said hub and said gear means for driving said hub;
second free-wheel ratchet means coupled between said pedal drive shaft and said sun gear means for driving said sun gear means by said drive shaft in the absence of meshing of said ring gear with any of said multiple sets of said planet gears;
and
ring gear positioning means operable for axially moving said ring gear along said guide tracks whereby said hub is adapted to be driven at a selected rate of rotation depending upon the particular set of said multiple sets of said planet gears engaged by said ring gear.

6 more elements

Dependencies are inferred from the claim text.