Abstract: A method of manufacturing a reinforced flexible tube in which a hard synthetic resin spiral core is embedded in and fused to a soft synthetic resin matrix through the medium of a semi-hard synthetic resin adhesive layer and the apparatus for carrying out the method of manufacturing the tube. Hard and semi-hard synthetic resin materials are simultaneously extruded from extruders to form a first composite linear element in which these two separate materials are firmly bonded together owing to the small extruding temperature difference between these two separate materials. The first composite linear element is preheated to make the temperature difference between the linear element and a soft synthetic resin material to be extruded on the linear element small.

Abstract: An apparatus for continuously manufacturing a reinforced plastic pipe in which a reinforced plastic strip having a substantially I-shaped reinforcing spiral core embedded therein and partly exposed out of the strip is wound on at least three segmental sleeves slidably mounted on rotary shafts whose centers are arranged at vertexes of a regular polygon, respectively. During rotation of the rotary shafts, those segmental sleeves which are in contact with an envelope that is tangent to the segmental sleeves are moved forward while those segmental sleeves which are not in contact with the envelope are moved backward in a smooth manner by a guide means. The alternate forward and backward movements of the segmental sleeves are capable of continuously manufacturing the reinforced plastic pipe without producing strain at the joints between the lateral edges of the successive turns of the plastic pipe.