Extrusion of thermoplastic materials
Abstract
Abstract In extruding rods and sections, or in coating wires and cables by extrusion, the rods, sections and coatings consisting of thermoplastic material and being of such substantial thickness as normally to lead, on cooling after extrusion, to the presence of voids therein, the thermoplastic material is extruded in the heated state through a die and then subjected to strong cooling by means of compressed air, water under pressure or other fluid medium under pressure, the pressure of the medium being sufficient to prevent the permanent formation of voids. The cooling-pressure medium may be passed through a tube through which the rod or coated wire is drawn. The tube may be attached at one end directly to the die, the rod or coated wire being drawn through a gland at the other end of the tube. The air, water, &c. may escape from the tube through the gland or through a pressure controlling valve. Specification 471,590, [Group IV], is referred to.
Inventors
- 👤 Williams Edmond George
Bibliographic Details
Claims Analysis
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1948-09-03 | 1949-03-05 | 1949-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1952-09-03 | 1953-03-05 | 1953-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1956-09-03 | 1957-03-05 | 1957-09-04 | $7700.00 | Window Closed / Lapsed |