| 摘要 |
658,890. Making escapement-wheels. BULOVA WATCH CO., Inc. March 22, 1949, No. 7832. Convention date, Dec. 31, 1948. [Classes 83 (ii) and 83 (iv)] Punching.-In a method of punching out lever escapement-wheels in successive stages from sheet metal strip, the gaps 3 between the teeth are first punched out, the spokes 5 are then cut and the wheel is finally detached by punching the impulse faces 11. The wheels are punched out from strip 1 located by holes 2 in a tool comprising stages of equally spaced rings of punches and dies for (1) rough punching of tooth gaps, 3, Fig. 1; (2) punching undercut faces 4; (3) punching out spokes 5; (4) recutting tooth gaps 3 to counteract distortion caused in previous stages; (5) re-cutting spokes 5; (6) punching heels of teeth by cylindrical punches 7, Fig. 6; (7) punching central holes 8 ; (8) detaching blank from the strip by cutting the impulse faces 11 by means of flat faces 10, Fig. 8, on cylindrical punches 9. |
