Coupling members that join first and second rotary members

A coupling member to join first and second rotary members, the coupling member comprising:

• a unitary body having a first coupling element, a second coupling element, and a hub, wherein the unitary body forms a single piece with the hub extending between and connecting the first coupling element to the second coupling element,
• wherein:
• the first coupling element defines a first plane, the second coupling element defines a second plane with the first and second planes being parallel, and the hub defines a hub axis normal to the first and second planes,
• the first coupling element comprises a plurality of first connection elements arranged about a circumference of a first circle having a first radius extending from the hub axis, wherein a material of the first coupling element in the first circle and in the first plane is less than the area of the first circle, and
• the second coupling element comprises a plurality of second connection elements arranged about a circumference of a second circle having a second radius extending from the hub axis, wherein a material of the second coupling element in the second circle and in the second plane is less than the area of the second circle;
• wherein the second circle is different than the first circle.