| 摘要 |
PROBLEM TO BE SOLVED: To provide a tapered metal tube in which a fore end thereof is tapered in a conical shape, and an opening is formed in a fore end face. SOLUTION: Four parts in four directions at right angles from each other in a section of a circular metal tube (an original circular part 7) are pressed toward the center of the tube to form grooves 3 in the longitudinal direction of the tube, and gradually tapered in a conical shape. An opening 4 is formed at the center of the tube in a fore end face of a grooved conical tapered part 6. In a part in a vicinity of the fore end, the grooves 3 are formed in four directions at right angles from each other from the original circular part 7 shown by (A) in Figure, and drawn in a conical shape, and the opening 4 is formed as shown in (D) in Figure immediately in a vicinity of the fore end face. In this sectional shape, the tapered metal tube with its fore end being not closed can be easily obtained. A special tapered metal tube conical in shape and having an opening at the fore end can be easily obtained at low cost. COPYRIGHT: (C)2007,JPO&INPIT
|
