초록 ▼

A rotable sprocket assembly transmits force from a chain into rotation of a bicycle wheel. Sprocket segments having peripheral teeth are mounted on a pair of sprocket housings so that the combined periphery of the sprocket segments is substantially circular. The housings are stationary relative to e

A rotable sprocket assembly transmits force from a chain into rotation of a bicycle wheel. Sprocket segments having peripheral teeth are mounted on a pair of sprocket housings so that the combined periphery of the sprocket segments is substantially circular. The housings are stationary relative to each other and each is oriented in a plane which is normal to a central rotational axis. The sprocket segments are slidable relative to the housing in a radial direction so as to vary the diameter of the combined sprocket segments. Each sprocket segment is formed from a plurality of hinged subsegments, with each subsegment having a single tooth. The sprocket segments of one housing overlap the adjacent sprocket segments on the other housing so that the pairs of overlapping teeth combine to effectively form a single tooth. The sprocket segments are movable angularly relative to the sprocket housings, so that in combination with the radial displacement of the sprocket segments, the total number of effective teeth on the sprocket assembly can be varied in increments of one tooth. The sprocket segments are retained in a desired radial position by a disengageable latch mechanism. A shift actuator causes disengagement of the latch and angular displacement of the sprocket segments to a desired position. Movement of the shift actuator is accomplished manually or automatically through a motor and an electronic control system. The wheel and sprocket assembly permit removal of the wheel without requiring removal of the sprocket assembly.

대표청구항 ▼

A sprocket assembly which is rotatable upon application of a force from a drive member which engages said sprocket assembly, said sprocket assembly being expandable so as to vary the mechanical advantage applied to said sprocket assembly, said sprocket assembly comprising: a first sprocket housing w

A sprocket assembly which is rotatable upon application of a force from a drive member which engages said sprocket assembly, said sprocket assembly being expandable so as to vary the mechanical advantage applied to said sprocket assembly, said sprocket assembly comprising: a first sprocket housing which is rotatable about a central axis, said first sprocket housing being oriented in a first plane which is substantially normal to said central axis; a second sprocket housing which is rotatable about said central axis, said second sprocket housing being stationary relative to said first sprocket housing and oriented in a second plane which is substantially parallel to said first plane; at least one sprocket segment mounted on each of said sprocket housings, said segments including means for engaging said drive member so that motion of said drive member is transmitted into rotation of said sprocket assembly about said central axis, each of said sprocket segments being movable relative to said respective housing in a substantially radial direction; and wherein said sprocket segment on said first housing and said sprocket segment on said second housing cooperate to define a variety of combined peripheral shapes so as to permit variation in the mechanical advantage applied to said sprocket assembly by said drive member.