A releasable plug connection for inserting a nozzle tube into a jack includes a hollow cylinder and a sleeve displaceably mounted on the cylinder. A nozzle tube, forming the hollow cylinder, is provided with radially spring-loaded lugs, the free ends of which are in contact with a locking surface. The locking surface is formed on a flange of the sleeve, which can slide relative to the hollow cylinder against the force of a spring. To release the connection, the sleeve is pushed back so that the lugs are pushed inwardly, and ends of the lugs slide from the locking surface. As soon as the lug ends have left the locking surface, the nozzle tube shoots from the jack under the action of the spring.
