Crank assembly for a bicycle bottom bracket assembly, shaft and crank arm thereof

Crank assembly for a bicycle bottom bracket assembly, comprising:

• a right crank arm and a left crank arm;
• a shaft having a body extending along a longitudinal axis by a predetermined distance to join the right and left crank arms in an assembly;
• at least one of said crank arms being associated with at least one free end of said shaft;
• and
• a coupling between said at least one free end of said shaft and said at least one crank arm associated with said at least one free end of said shaft;
• wherein said coupling comprises first front coupling teeth projecting axially from an axial end surface of said at least one free end of said shaft, each of the first front coupling teeth including respective opposite side surfaces joined by a first top surface and a plurality of first throats defined between adjacent teeth, the first top surface being inclined at an oblique angle with respect to the longitudinal axis of the shaft, and second front coupling teeth projecting axially from an axial end surface of said at least one crank arm associated with said at least one free end of said shaft, each of the second front coupling teeth including respective opposite side surfaces joined by a second top surface and a plurality of second throats defined between adjacent teeth, the second top surface being inclined at an oblique angle with respect to the longitudinal axis of the shaft, top surfaces are displaced from the plurality of second throats, and the second top surfaces are displaced from the plurality of first throats, said first and second front coupling teeth being coupled together such that contact between said first and second front toothings occurs solely at a curved base surface of only one of said first and second plurality of throats and/or between said side surfaces of said teeth of both first and second front coupling teeth.

A bicycle crank and bottom bracket comprising:

• a housing extending along a longitudinal axis and having spaced apart ends;
• a shaft positioned within the housing and having a body extending along the longitudinal axis by a predetermined distance with a first defined toothed pattern that extends circumferentially over an end surface of at least one free axial end of the shaft;
• two crank arms rotatably mounted to the housing and joined in an assembly by the shaft, where at least one of the two crank arms has a coupling portion with a second defined toothed pattern that corresponds to the first defined toothed pattern associated with the at least one free axial end of the shaft, the second defined toothed pattern extending circumferentially over an end surface of the coupling portion of the at least one of the two crank arms;
• and
• coupling means arranged between the crank arms and the housing;
• whereby the first and second defined toothed patterns are mated and the shaft connects the two crank arms in a centered relationship about the longitudinal axis, the first and second defined toothed patterns each having an axial end surface that is sloped along a radius of the shaft, a plurality of teeth that each includes a pair of side surfaces, and a plurality of throats, each throat being defined between two adjacent teeth, wherein contact between said first and second defined toothed patterns occurs solely at a curved base surface of said throats defined between said teeth of only one of said first and second defined toothed patterns and/or between said side surfaces of said teeth of both first and second defined toothed patterns.

A bicycle crank and bottom bracket comprising:

• a housing extending along a longitudinal axis and spaced apart ends;
• a shaft positioned within the housing and extending along the longitudinal axis by a predetermined distance with spaced apart first and second axial ends that each has a defined toothed pattern that extends uninterrupted over an entire end surface of a respective one of the first and second axial ends;
• right and left crank arms, each having a coupling portion with a defined toothed pattern that extends uninterrupted over an entire end surface of the coupling portion and corresponds to the defined toothed pattern associated with one of the first and second axial ends of the shaft;
• and
• coupling means between the crank arms and the housing;
• whereby the toothed patterns of the right and left crank arms mates with the toothed patterns of the first and second axial ends of the shaft, the coupling means rotatably mounts the crank arms to the housing, and the shaft connects the crank arms in a centered relationship about the longitudinal axis, each one of the defined toothed patterns of the crank arms and the first and second axial ends of the shaft having an axial end surface inclined at an oblique angle with respect to the longitudinal axis, a plurality of teeth that each includes a pair of side surfaces, and a plurality of throats, each throat being defined between two adjacent teeth, wherein contact between the toothed patterns of the right crank arm and the first axial end of the shaft occurs solely at a curved base surface of the throats defined between the teeth of only one of the right crank arm and the first axial end of the shaft and/or between the side surfaces of the teeth of both the right crank arm and the first axial end of the shaft, and contact between the toothed patterns of the left crank arm and the second axial end of the shaft occurs solely at a curved base surface of the throats defined between the teeth of only one of the left crank arm and the second axial end of the shaft and/or between the side surfaces of the teeth of both the left crank arm and the second axial end of the shaft.