| 摘要 |
1,131,585. Corrugating; drawing. CALUMET & HECLA Inc. 23 June, 1967 [6 March, 1967], No. 29178/67. Headings B3E and B3P. A fluted tube is formed by first bending the tube wall to form longitudinally extending flutes and thereafter substantially reducing the outside tube diameter. As described, a copper nickel tube is first drawn past a plurality of clamped rods 40 circumferentially spaced apart in a ring 36 to form longitudinal flutes in the tube, which is then drawn through a die 58 of fluted cross-section aligned with the ring 36. Positioned within the compound die is a mandrel 32 having a fluted section 68 extending from a connector 70 to lie within the die section 58, and an adjustably mounted nylon section 76 co-operating with the rods 40. |
