Which coupling allows for axial flexibility movement in operation, made with alternate materials into two flanges?

The flexible disk coupling is designed to accommodate axial misalignment between two shafts while still transmitting torque. It typically consists of two circular plates, known as flanges, and a flexible disk made from a material that allows it to bend and flex. This design effectively allows for some movement in the axial direction, which is beneficial if there are variations in alignment during operation.

In contrast, the other options have specific uses or limitations that make them less suitable for this particular function. The flexible toroidal spring coupling permits angular and radial misalignment but is not primarily designed for axial flexibility. The flexible Oldham coupling, while it can handle misalignments, operates by using a central disk that allows limited movement rather than full axial flexibility. The elastic material bonded coupling utilizes elasticity to connect components but does not inherently provide the same level of axial flexibility as the flexible disk coupling.

Thus, the combination of flanges and a flexible disk in a flexible disk coupling makes it the ideal choice for applications requiring axial flexibility.