| 摘要 |
<p>PURPOSE:To enable the rib made of hard synthetic resin to be integrally molded spirally outside of an inner tube when the tube is extruded from an extrusion molding machine by a method in which only the outermost hard synthetic resin layer having been extruded in concentric condition is sheared in a prescribed width and is pressure bonded onto an inside tube body, and then said shearing and pressure bonding are moved in order along its peripheral direction. CONSTITUTION:The outer layer A1 and the inner layer A2 composing a tube body A and the hard synthetic resin layer B1 composing ribs B are extruded in concentric condition with an extruding mold 1. Since on one hand, the shearing die 8 moved inwardly in radial direction by the pushing force of a pushing roller 16, 16', is moved along circumferential direction in order, the hard synthetic resin layer B1 is sheared by the action of its movement to the inward from the outward in the radial direction of the shearing die 8. Since the shearing die 8 is moved in order in circumferential direction with the rotation of the pushing roller 16, 16', the ribs cut out by the shearing with the linear pushing of the hard synthetic resin layer B1 became spiral continuously. Moreover said ribs are embossed in a prescribed shape with the embossing part 14 of the shearing die 8, and are integrally pressure bonded onto the outer peripheral surface of the tube body A.</p> |
