Abstract: The driving coupling member and the driven coupling member of a flexible coupling are tied together by a plurality of flexible torque-transmitting members which are arranged in a circular pattern. Each torque-transmitting member consists of an endless, substantially elliptical loop of an elastic material, e.g. rubber, which may be re-inforced by an appropriate woven material. Resilient inserts are placed into the elliptical cavities defined by the torque-transmitting members, and these inserts are compressed when the torque-transmitting members are elongated as a result of the transmission of torques between both coupling members. The aforementioned resilient inserts expand when the amount of torque transmitted is reduced. The expansion and contraction of the aforementioned inserts are transmitted to containers of a fluid medium and cause said fluid medium to flow out of a contracting container into another container. The flow of fluid is controlled by a restricted orifice.