US 7,004,487 B2 · Continuously variable transmission for bicycles

Abstract

A continuously variable transmission for bicycles having a transmission mechanism including a plurality of link units for converting rotary motion of an input shaft rotated by a pedal-operated crankshaft into swinging motion, and a one-way clutch for converting the swinging motion into rotary motion of an output shaft. The link units have drive links pivotally mounted on an eccentric ring which rotates in unison with the input shaft. The continuously variable transmission is disposed between a front wheel and a rear wheel of a bicycle in the longitudinal direction thereof and disposed either upwardly of a hypothetical plane which contains the axes of rotation of the front wheel and the rear wheel or upwardly of a position below and near the hypothetical plane. The transmission so configured provides better bicycle maneuverability, lower cost, while suffering almost no danger of contacting the ground.

Claims20

Dependent claims

A continuously variable transmission adapted to be disposed on a bicycle frame of a bicycle in a position between front and rear wheels of the bicycle in a longitudinal direction thereof and substantially upwardly of a plane which contains an axis of rotation of said front wheel and an axis of rotation of said rear wheel, the continuously variable transmission comprising:

a transmission mechanism having a plurality of link units, each comprising a plurality of transmission links, for converting rotary motion of an input shaft rotated by a pedal-operated crankshaft into swinging motion;
a one-way clutch coupled to each of said link units for converting the swinging motion of the link units into rotary motion of an output shaft;
and
a transmission control mechanism for moving an end of a transmission control link having an opposite end pivotally coupled to each of said link units thereby to continuously vary the rotational speed of said output shaft,
wherein a drive link of said transmission links of each of said link units is pivotally supported on an eccentric ring coupled to said input shaft for rotation in unison therewith.

2 more elements

A bicycle with a continuously variable transmission comprising:

a pair of right and left main frames extending rewardly and downwardly from a head pipe;
a down tube extending obliquely downwardly from front ends of the main frames below the main frames;
a transmission mechanism having a plurality of link units, each comprising a plurality of transmission links, for converting rotary motion of an input shaft rotated by a pedal-operated crankshaft into swinging motion;
a one-way clutch coupled to each of said link units for converting the swinging motion of the link units into rotary motion of an output shaft;
and
a transmission control mechanism for moving an end of a transmission control link having an opposite end pivotally coupled to each of said link units thereby to continuously vary the rotational speed of said output shaft,
wherein a drive link of said transmission links of each of said link units is pivotally supported on an eccentric ring coupled to said input shaft for rotation in unison therewith, said continuously variable transmission being disposed between front and rear wheels of the bicycle in a longitudinal direction thereof and substantially upwardly of a hypothetical plane which contains the axis of rotation of said front wheel and the axis of rotation of said rear wheel.

4 more elements

Dependencies are inferred from the claim text.

Continuously variable transmission for bicycles

Life of this patent

Continuously variable transmission for bicycles

Life of this patent

Abstract

Claims20