| 摘要 |
PURPOSE:To produce a thimble having excellent durability with good productivity without need for welding by press fitting dies for forming collar parts from the top and bottom ends of an annealed pipe material to flare the ends of the pipe material and to form the collar parts then shaping the collar parts. CONSTITUTION:Dies 1 for forming collar parts each having a circular conical surface 4 diverging at a relatively small degree are press fitted into a pipe material 2 to the poistion of virtual lines from the top and bottom of the cylindrical hole 3 of said material by a press machine, thereby flaring the circumferential walls 2a at the top and bottom ends of the material 2 toward a diametral direction. Dies 1 for forming collar parts each having a circular conical surface diverging more largely than the surface 4 of the dies 1 are forced into the hole 3 of the material 2 to virtual lines to expand largely the circumferential walls 2a at the top and bottom ends of the material 2. The material 2 is then pressed by dies 1 for forming collar parts each having a circular conical surface 4 of which the part 4a near the circumferential edge is made approximately level. A blank material 7 formed with discoid collar parts 5 at the top and bottom in the axial direction of the material 2 is thus obtd. The material 7 is pressed by dies 8 for shaping from the right and left on the outside and is thus shaped to a thimble 9 of a water dropping type in a shaping stage B. |
