| 摘要 |
1,127,422. Rolling finned tubes. CALUMET & HECLA, Inc. 22 March, 1966 [16 Aug., 1965], No. 12688/66. Heading B3M. An apparatus for forming fine pitch helical fins, i.e. at least 26 per inch, on a tube T comprises three arbors uniformly positioned about the axis of the tube fed axially between them by the arbors, each arbor having fin forming discs 1-10 mounted on it in two groups 12, 14 separated by a spacer 16. The first group 12 is comprised of discs 10-8 which have narrower peripheral rims than the discs 7-1 of the second group, Figs. 2 and 3 (not shown), The discs 10-8 serve to start the fin formation whereas the discs 7-1 of the second group serve to shape the fins. One of the arbors 22, Fig. 1, has the first disc of the second group of similar dimensions to the first disc of the first group, i.e. disc 10. The arbors are mounted with their axes at an angle to the axis of the tube T. The arbors are arranged so that the tube has two-start finning, Fig. 5 (not shown), but features of the invention are applicable to single or triple-start finning. Reference has been directed by the Comptroller to Specification 756,114. |
