| 摘要 |
<p>A flexible plastic tube, comprises, an extruded inner tube or tubular portion and an extruded outer tube or tubular portion of a thermoplastic material overlying the inner tubular portion and spaced radially outwardly therefrom and including a reinforcing strip of substantially U-shape configuration wound around the inner portion and bonded to the inner and outer tubular portions. The reinforcing strip has radially extending sidewalls in the form of fins which define a first cavity therebetween and, in addition, successive turns of the reinforcing strip define a second cavity therebetween which is located between the outer and inner walls. The sidewalls advantageously have radially outwardly tapered cross-sectional shapes. The inner wall is first extruded and may advantageously be reinforced by embedding axially reinforcing fibers in its outer surface and, while it is still not set, the reinforcing strips of a harder material in the inner and outer walls are wound around the inner wall so that it becomes bonded to the inner wall as the inner wall is set. Thereafter, the outer wall is extruded and bonded immediately to the leg portions of the reinforcing strip. In addition, a metalized material may be positioned by alignment of grooves into the first cavity between the sidewalls of the reinforcing strip and applied under tension during the application of the outer wall.</p> |
