Double-walled tube assembly
US4906496A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Oct 14, 1987 |
| Grant date | Mar 6, 1990 |
| Priority date | — |
| Expiry date | Oct 14, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24744
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A double-walled tube assembly has an elongate inner tube of thermoplastic resin, and an elongate extruded outer tube of thermoplastic resin including a plurality of ribs having a constant height longitudinally of the outer tube and extending over the entire length of the outer tube, the ribs projecting toward the center of the outer tube. The ribs have distal ends fused to the outer perpiheral surface of the inner tube over the entire length of the inner and outer tubes. The rib width is from 0.5 to 1.5 mm. To continuously manufacture the double-walled tube assembly, the pre-molded inner tube is fed to an extrusion molding machine having a cross-head die, and thermoplastic resin is extruded from the cross-head die into an elongate outer tube around the inner tube. The inner tube and the extruded outer tube are fed into a sizing die device, in which the outer tube in a softened state is contracted toward the outer peripheral surface of the inner tube until the distal ends of the ribs of the outer tube are fused to the outer peripheral surface of the inner tube.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.