A device for releasably coupling together various objects includes a first profiled tube mounted on a first object, a second profiled tube mounted on a second object to be coupled together with the first object, and a locking rod. The tubes are essentially identical at least in their cross section and have a longitudinal open slot with smaller width than the cross section of the tubes. For coupling, a first circumferential portion of the first tube is inserted through the slot in the second tube, while a circumferential portion of the second tube is inserted through the slot in the first tube. Inside each tube the circumferential portion of the coacting tube is brought into contact with a portion of the interior boundary surface of the respective tube, so that the two tubes will form a sleeve-like unit. The locking rod is inserted into a cavity in this unit to lock the two tubes to each other.