Sprocket assembly for a bicycle
A bicycle sprocket assembly having a first sprocket of larger diameter and a last sprocket of smaller diameter. The last sprocket has a plurality of throats, arranged between two consecutive teeth, with respective bottom surfaces substantially tangent to a first circumferential diameter. The sprocket assembly includes a plurality of spacers arranged between the first and last sprockets with at least one spacer arranged between the last sprocket and a second-last sprocket. The last spacer comprises a radially outer surface having a second diameter greater than the first diameter and including a plurality of recessed areas, each recessed area is positioned at a respective throat of the plurality of throats. The recessed areas comprise respective base surfaces substantially tangent to a second circumference having a third diameter smaller than or equal to the first diameter.
1. A bicycle sprocket assembly, comprising:
a plurality of sprockets of decreasing diameter configured to be mounted on a freewheel body of a bicycle hub, said plurality of sprockets including a first sprocket of larger diameter and a last sprocket of smaller diameter, wherein said last sprocket comprises a plurality of teeth and a plurality of throats, each throat being arranged between two consecutive teeth, said throats comprising respective bottom surfaces substantially tangent to a first circumference having a first diameter; and,
a plurality of spacers arranged between said first sprocket and said last sprocket, said plurality of spacers including a last spacer arranged between said last sprocket and a second-last sprocket of said plurality of sprockets and having a radially inner surface configured to be fitted onto a free end portion of said freewheel body;
wherein said last spacer comprises a radially outer surface having a second diameter greater than said first diameter and including a plurality of recessed areas, each recessed area being positioned at a respective throat of said plurality of throats, wherein said recessed areas comprise respective base surfaces substantially tangent to a second circumference having a third diameter smaller than or equal to said first diameter.
2. The sprocket assembly according to claim 1 , wherein said last sprocket has ten teeth and said second-last sprocket has eleven or twelve teeth.
3. The sprocket assembly according to claim 2 , wherein said last sprocket is configured to be mounted cantilevered with respect to said freewheel body.
4. The sprocket assembly according to claim 3 , wherein said freewheel body has a radially outer surface comprising a plurality of longitudinal grooves defining a plurality of projections and a plurality of recesses, each recess being arranged between two consecutive projections, wherein said projections comprise respective head surfaces that belong to a third circumference having a fourth diameter greater than said first diameter.
5. The sprocket assembly according to claim 4 , wherein said last spacer is a single piece with said last sprocket and said second-last sprocket.
6. The sprocket assembly according to claim 5 , wherein said last sprocket, said last spacer and said second-last sprocket are a single piece with a third-last sprocket of said plurality of sprockets.
7. The sprocket assembly according to claim 6 , wherein said last spacer in a single piece with said last sprocket and said second-last sprocket.
8. The sprocket assembly according to claim 7 , wherein said last sprocket, said last spacer and said second-last sprocket are a single piece with a third-last sprocket of said plurality of sprockets.
9. The sprocket assembly according to claim 2 , wherein said freewheel body has a radially outer surface comprising a plurality of longitudinal grooves defining a plurality of projections and a plurality of recesses, each recess being arranged between two consecutive projections, wherein said projections comprise respective head surfaces that belong to a third circumference having a fourth diameter greater than said first diameter.
10. The sprocket assembly according to claim 9 , wherein said last spacer is a single piece with said last sprocket and said second-last sprocket.
11. The sprocket assembly according to claim 10 , wherein said last sprocket, said last spacer and said second-last sprocket are a single piece with a third-last sprocket of said plurality of sprockets.
12. The sprocket assembly according to claim 1 , wherein said last sprocket is configured to be mounted cantilevered with respect to said freewheel body.
13. The sprocket assembly according to claim 12 , wherein said freewheel body has a radially outer surface comprising a plurality of longitudinal grooves defining a plurality of projections and a plurality of recesses, each recess being arranged between two consecutive projections, wherein said projections comprise respective head surfaces that belong to a third circumference having a fourth diameter greater than said first diameter.
14. The sprocket assembly according to claim 1 , wherein said freewheel body has a radially outer surface comprising a plurality of longitudinal grooves defining a plurality of projections and a plurality of recesses, each recess being arranged between two consecutive projections, wherein said projections comprise respective head surfaces that belong to a third circumference having a fourth diameter greater than said first diameter.
15. The sprocket assembly according to claim 1 , wherein said last spacer is a single piece with said last sprocket and said second-last sprocket.
16. The sprocket assembly according to claim 15 , wherein said last sprocket, said last spacer and said second-last sprocket are a single piece with a third-last sprocket of said plurality of sprockets.
17. The sprocket assembly according to claim 16 , comprising a second-last spacer arranged between said second-last sprocket and said third-last sprocket, wherein said second-last spacer comprises a radially outer surface having a fifth diameter greater than said second diameter.
18. The sprocket assembly according to claim 1 , wherein said radially inner surface is a cylindrical surface with a circular section.
19. The sprocket assembly according to claim 1 , wherein said second-last sprocket comprises a radially inner surface having a shape matching the radially outer surface of said freewheel body.
20. A bicycle sprocket assembly, comprising:
a plurality of sprockets mounted on a freewheel body of a bicycle hub, said plurality of sprockets including a first sprocket of a largest diameter and a last sprocket of a smallest diameter, wherein said last sprocket comprises a plurality of teeth and a plurality of throats, each throat being arranged between two consecutive teeth, said throats comprising respective bottom surfaces substantially tangent to a first circumference having a first diameter; and,
a plurality of spacers arranged between said first sprocket and said last sprocket, said plurality of spacers including a last spacer arranged between said last sprocket and a second-last sprocket of said plurality of sprockets and having a radially inner surface configured to be fitted onto a free end portion of said freewheel body; and, said last spacer comprises a radially outer surface having a second diameter greater than said first diameter and including a plurality of recessed areas, each recessed area being positioned at a respective throat of said plurality of throats, wherein said recessed areas comprise respective base surfaces substantially tangent to a second circumference having a third diameter smaller than or equal to said first diameter.