Sprocket support member for a bicycle sprocket assembly
A bicycle sprocket assembly having at least one subassembly including a sprocket support member and two sprockets. The support member has at least one engagement portion for coupling it to a bicycle freewheel and at least one fastening portion arranged in a radially external position with respect to the engagement portion. Both sprockets are fixed on the sprocket support member on the same side of the fastening portion.
1. A sprocket support member for a bicycle sprocket assembly comprising a plurality of single structural units angularly equidistant from each other and connected together by zones having reduced dimensions in the radial direction and at least one freewheel hub engagement portion having at least one tooth engagable with a splined surface of a bicycle freewheel hub and at least one fastening portion having at least one hole for the mounting of the sprocket support member wherein the fastening portion is defined within a first plane and the engagement portion is defined in a second plane and the first plane is axially displaced with respect to the second plane and the planes are parallel to each other wherein one of the at least one fastening portion and one of the at least one engagement portion form at least one single structural unit, the one of the at least one engagement portion being aligned with the one of the at least one fastening portion in a radial direction.
2. The sprocket support member of claim 1 , including an axial projection located between the engagement portion and the fastening portion.
3. The sprocket support member of claim 2 , wherein the axial projection forms a support against which a radially projecting portion of a fastening element can rest.
4. The sprocket support member of claim 3 , wherein the axial projection has a centering and support seat having the shape of a cylindrical sector coaxial with a fastening hole of the fastening portion.
5. The sprocket support member of claim 3 , wherein the axial projection is located at the base of a radial contact surface of the fastening portion.
6. The sprocket support member of claim 1 , wherein the fastening portion has an axial thickness substantially equal to a desired axial distance between multiple sprockets of the sprocket assembly.
7. The sprocket support member of claim 1 , wherein the structural unit includes at least one weight-saving cavity located between the engagement portion and the fastening portion.
8. The sprocket support member of claim 1 , wherein the support member is made of a material chosen among the group consisting of: steel, aluminum and its alloys, titanium, and fabric made of structural fibers incorporated in a matrix of plastic material, in which the fibers are chosen among carbon fibers, glass fibers, aramid fibers, boron fibers, ceramic fibers or any combination thereof.