| 摘要 |
PURPOSE:To manufacture the blade fitting of a rotary harrow easily by inserting center dies which each have an arcuate notch atop into rectangularly sectioned die steel from both sides until they face each other at a center part, and pressing down an upper die equipped with a punch in a specific shape. CONSTITUTION:The die steel 15 which is sectioned rectangularly and has length double as great as necessary length is placed on a lower die 16 and the center dies 17 and 17 which each have the arcuate notch 18 atop are inserted from both-end opening parts so that their tip notch parts face each other. The arcuate notch 18 has the same curvature that the rotating shaft of the rotary harrow using the dies has. In this state, the upper die 24 is pressed down under hydraulic pressure, etc., to perform cutting with a punch 19 having an edge in a shape corresponding to the notch 18, and thus the arcuate notch 18 is formed; and then an insertion hole 6 for a blade fitting bolt is formed with a punch 20, thereby manufacturing the blade fitting easily. |
