Toothed crown for a bicycle crankset

Patent metadata

Field	Value
Publication number	US-10859149-B2
Application number	US-201815982366-A
Country	US
Kind code	B2
Filing date	May 17, 2018
Priority date	May 22, 2017
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

A bicycle crankset annular body with a toothed crown that extends about a rotation axis and has axially inner and outer surfaces and a reference plane (R) on which the rotation axis (O) and a longitudinal axis of a right crank arm lies. The annular body's maximum axial thickness, defined at a first angular portion, is between two parallel planes that are orthogonal to the reference plane (R). The angular portion has a lightening recess formed on the axially outer surface between two delimiting planes that pass through the rotation axis (O) and are inclined with respect to the reference plane (R) by first and second angles which are measured on axially outer surface moving angularly in the clockwise direction from the reference plane (R).

First claim

What is claimed is:

1. A toothed crown for a bicycle crankset, comprising an annular body extending about a rotation axis, a plurality of teeth that extend from said annular body along respective radially outer directions, and a plurality of coupling portions for coupling with a bicycle right crank arm and that extend from said annular body on an opposite side to said plurality of teeth,
said annular body comprising:
an axially inner surface;
an axially outer surface;
a reference plane on which said rotation axis lies and a longitudinal axis of said right crank arm is intended to lie when said right crank arm is coupled with said annular body at said plurality of coupling portions and at said axially outer surface;
the annular body having a maximum axial thickness equal to a distance between two main planes parallel to each other and orthogonal to said reference plane, said maximum axial thickness being defined at at least one first angular portion of said annular body;

wherein said at least one first angular portion of said annular body comprises a first lightening recess formed on said axially outer surface,
wherein said at least one first angular portion extends circumferentially between a first delimiting plane and a second delimiting planes that pass through said rotation axis,
the first delimiting plane is inclined with respect to said reference plane by a first angle of between 21° and 27°, and
the second delimiting plane is inclined with respect to said reference plane by a second angle between 67° and 73°,
wherein said first angle and said second angle are measured on said axially outer surface moving angularly in a clockwise direction from said reference plane.

2. A toothed crown according to claim 1 , wherein said at least one first angular portion is free from lightening recesses on said axially inner surface.

3. The toothed crown according to claim 2 , wherein a second angular portion of said annular body comprises a second lightening recess formed on said axially outer surface, wherein said second angular portion is diametrically opposite to said at least one first angular portion with respect to said rotation axis.

4. The toothed crown according to claim 3 , wherein said second angular portion is free from lightening recesses on said axially inner surface.

5. The toothed crown according to claim 3 , wherein the number of said plurality of teeth is 28 to 44.

6. The toothed crown according to claim 3 , wherein a first tooth is arranged substantially astride of, or in close proximity to, said reference plane, a thirteenth tooth and a twenty-ninth tooth are arranged between said two delimiting planes, the thirteenth and the twenty-ninth tooth being counted on said axially outer surface moving circumferentially in a counter-clockwise direction from said first tooth.

7. The toothed crown according to claim 3 , wherein said plurality of coupling portions comprises two pairs of coupling portions symmetrically arranged on opposite sides with respect to said reference plane.

8. A toothed crown according to claim 1 , wherein a second angular portion of said annular body comprises a second lightening recess formed on said axially outer surface, wherein said second angular portion is diametrically opposite to said at least one first angular portion with respect to said rotation axis.

9. A toothed crown according to claim 8 , wherein said second angular portion is free from lightening recesses on said axially inner surface.

10. A toothed crown according to claim 1 , wherein the number of said plurality of teeth is 28 to 44.

11. A toothed crown according to claim 10 , wherein a first tooth is arranged substantially astride of, or in close proximity to, said reference plane, a thirteenth tooth and a twenty-ninth tooth are arranged between said two delimiting planes, the thirteenth and the twenty-ninth tooth being counted on said axially outer surface moving circumferentially in a counter-clockwise direction from said first tooth.

12. A toothed crown according to claim 1 , wherein said plurality of coupling portions comprises two pairs of coupling portions symmetrically arranged on opposite sides with respect to said reference plane.

13. A toothed crown according to claim 12 , wherein a first coupling portion of a first pair of said two pairs of coupling portions is arranged at said at least one first angular portion.

14. A toothed crown according to claim 13 , wherein a second angular portion of said annular body comprises a second lightening recess formed on said axially outer surface, wherein said second angular portion is diametrically opposite to said at least one first angular portion with respect to said rotation axis, wherein a first coupling portion of a second pair of said two pairs of coupling portions is arranged at said second angular portion.

15. A toothed crown according to claim 14 , wherein the annular body comprises, at a second coupling portion of said first pair of said two pairs of coupling portions and at a second coupling portion of said second pair of said two pairs of coupling portions, a third and a fourth lightening recess, respectively, formed on said axially outer surface.

16. A toothed crown according to claim 15 , wherein the annular body comprises, at said second coupling portions, respectively a fifth and a sixth lightening recess formed on said axially inner surface.

17. A toothed crown according to claim 16 , wherein each of said fifth and sixth lightening recesses comprises a first recess portion arranged in a radially outer position with respect to the respective second coupling portion and a second recess portion that extends from said first recess portion towards the first coupling portion of the respective pair of said two pairs of coupling portions.

18. A toothed crown according to claim 17 , wherein said second recess portion has a radial extension shorter than that of said first recess portion.

19. A toothed crown according to claim 17 , wherein said second recess portion has an axial depth shorter than that of said first recess portion.

20. A toothed crown according to claim 1 , wherein the annular body comprises a plurality of depressions formed on said axially outer surface, each of said plurality of depressions being arranged between two respective circumferentially consecutive coupling portions and extending asymmetrically with respect to a radial plane angularly equidistant from said two circumferentially consecutive coupling portions.

Assignees

• Campagnolo Srl

Inventors

• Civiero Mirco

Classifications

• B62M9/02 Primary

  of unchangeable ratio · CPC title

• B62M9/105

  involving front sprocket chain-wheels engaged by the chain, belt or the like · CPC title

• B62M9/00 Primary

  Transmissions characterised by use of an endless chain, belt, or the like (cycle chain guards B62J13/00) · CPC title

• F16H55/303

  for round linked chains, i.e. hoisting chains with identical links · CPC title

• F16H55/30 Primary

  Chain-wheels · CPC title