| 摘要 |
962,304. Rotary rubbing tools. GENERAL AMERICAN TRANSPORTATTON CORPORATION. Sept. 11, 1962 [Oct. 25, 1961], No. 34649/62. Heading B3V. A fluteless thread forming tool comprises an elongated threaded shank having a rear body portion provided with a uniform thread and a front pilot end provided with threads carrying lobes. The tool, which may be a tap or a self-tapping screw, is formed, by rolling between dies, with lobes 21, 31, 41, and 51 which either decrease, increase, or remain the same size as they approach the screw end. They may be skewed relative to the screw axis, if desired. The profile, Fig. 2, of the lobes may vary, the outer surface of lobes being parallel or sloped relative to the screw circumference. |
