An extruded bead of thermoplastics material and an extruded tape-like web of thermoplastics material are wrapped in a coordinated manner around a rotating mandrel to continuously form a corrugated, helically reinforced, uniquely constructed stretch hose having a thread-like exterior appearance dominated by the web extending in an inclined spiral as it bridges from an outer diameter of each reinforcing coil to an inner diameter of the next-formed reinforcing coil. When the hose is axially compressed, the thin web-defined wall that connects each adjacent pair of reinforcing coils advantageously has one portion that bends or folds radially outwardly, and another portion that bends or folds radially inwardly. Discrete lengths of the hose are treated to minimize stress, to reset memory, and to greatly enhance hose flexibility.

The invention relates to a ringed tubular sheath including at least one internal means (5) for clamping a tube (11) in particular, and more specifically a smooth tube, located inside said sheath, said sheath being unique in that at least one flexible area (8) is associated with the internal clamping means (5). The invention also relates to a method for manufacturing such a sheath, and to a method for maintaining a ringed tubular sheath on a tube (11), in which: a ringed tubular sheath is used according to the invention; the flexible area(s) (8) are controlled such as to the deform the sheath; the tube (11) is inserted in the ringed tubular sheath, and the flexible area(s) (8) are then released.

A pressure hose for a water-carrying system, especially for connecting sanitary taps or for connecting parts of the water-carrying system, having a corrugated inner hose made of plastic. At least one hose end of the pressure hose is provided with a connecting piece, designed such that it differs from the inner hose, for joining the pressure hose to a complementarily designed connecting piece of a sanitary tap and/or a part of the water-carrying system. The inner hose and the connecting piece are formed as one piece and the inner hose and the connecting piece are preferably produced via extrusion in a common extrusion process.

A system and method for replacing or substituting mold blocks in a corrugator, the corrugator comprising first and second tracks for carrying respective chains of mold blocks, each of the tracks comprising return tracks, wherein the system advances replacement mold blocks towards the return tracks to displace corresponding mold blocks in the mold block chains while the corrugator is in production and while the mold block chains are in motion.