Abstract: Within a cylinder of a double-acting piston-and-cylinder unit there is displaceably arranged a piston. A spatially moveable piston rod in the form of a universal or ball pivot-link chain is connected with the piston. The piston rod is lengthwise guided by tensioning or tie bolts internally of the cylinder, these tensioning bolts clamping towards one another both of the cylinder heads and piercingly extending through the cylinder. Externally of the piston-and-cylinder unit the piston rod is guided within a guide tube which is connected with one of the cylinder heads. This guide tube can possess a random spatial extent. At the piston rod there is attached a coupling element with which there can be coupled the object or the like which is to be moved. This coupling element extends through a longitudinal slot provided in the guide tube. The spatial mobility of the piston rod enables guiding the piston rod externally of the piston-and-cylinder unit in a random direction.