| 摘要 |
847,052. Non-metallic tubes. FONTAINE, J. July 29, 1958 [Aug. 2, 1957], No. 24370/58. Class 99(2). In a flexible plastic tubing made from a band rolled into a helix the band consists of a body portion comprising a core 1 of circular crosssection of relatively stiff thermoplastic material and an enveloping cover 2 of relatively flexible thermoplastic material, at least one flange extruding from the body portion being banded to the adjacent whorl of the helix and the body portions of adjacent whorls being spaced from each other by a distance not substantially greater than the overall thickness thereof. As shown in Fig. 2, the body portion is of circular cross-section and comprises flanges 3, 31 and 4, 41 in overlapping relationship. The body portion may also be elliptic, ovoid or parallele piped in shape and may comprise more than one core. In another embodiment, Fig. 6, the flange 6 is bonded to the enveloping cover 2<SP>1</SP>. The band is obtained using an extrusion machine the core being incorporated in the body portion as the latter is extruded, the band being subsequently coiled on to a mandrel and the contiguous convolutions being bonded as by self-welding.
|
