초록 ▼

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

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.

대표청구항 ▼

A flexible plastic tube, comprising an extruded inner tube portion, an extruded outer tube portion of a thermoplastic or elastomeric material overlying and radially spaced outwardly from said inner tube, a substantially U-shaped reinforcing strip, laterally spaced sidewall fins with a first cavity t

A flexible plastic tube, comprising an extruded inner tube portion, an extruded outer tube portion of a thermoplastic or elastomeric material overlying and radially spaced outwardly from said inner tube, a substantially U-shaped reinforcing strip, laterally spaced sidewall fins with a first cavity therebetween, said strip extending in a helical path between said inner and said outer tube portions and firmly joined to said inner tube portion and being made of a hard, thermoplastic or elastomeric material, with a helical second cavity formed between the turns of said reinforcing strip, said strip being radially bonded to said inner tube portion and said outer tube portion, said first cavity being empty and axially laterally bounded by said sidewalls of said reinforcing strip, and said fins each having a radially outwardly tapering cross-sectional shape symmetrically diverging from the radial median plane of said strip, by which the cross-sectional shape of said second cavity is tapered in the radially outward direction.