A flexible diaphragm coupler includes a flange having a central support and a flange element extending radially outwardly from the central support. The flange element includes a rim portion having an axially facing surface. The axially facing surface includes a plurality of interlock elements. A diaphragm member is disposed between the first flange and the second flange. The diaphragm member includes a diaphragm element. The diaphragm element includes a central support element and a disc member extending radially outwardly from the central support element. The disc member includes a rim element having an axially facing surface portion including a plurality of interlock members that connect with the plurality of interlock elements.