Abstract: In a coupling device for establishing a leakage-free connection between the interiors of two enclosures to permit the passage of fluid therebetween, which device includes two coupling tubes each arranged to be in communication with the interior of a respective enclosure and each being provided with a controllable closing member formed to define a closeable flow passage in its respective tube, the tubes being arrestable against one another in a position to establish a leakage-free connection between their flow passages, and two operating members each operatively associated with a respective closing member and movable relative to its associated closing member between a position in which the associated flow passage is closed and a position in which the associated flow passage is open, one of the operating members is provided with a coupling projection and the other of the operating members is provided with a recess formed to mate with the projection for causing the operating members to move in unison between the