US Patent 6997811 Sealed flexible motor coupling

A hermetic seal functions as a closure between opposite ends of the coupling by combining a metal sleeve and an elastomer sleeve extension. The metal sleeve is sealingly attached to the outer surface of one end of the coupling and the elastomer sleeve, sealingly attached to the metal sleeve, is attached at the distal end to the other end of the coupling. As an alternative, the distal end may be bonded to a second metal sleeve sealingly attached to the other end of the coupling. The seal may be convoluted, with multiple convolutions.