PURPOSE: To manufacture a pipe fitting with good dimensional accuracy without causing flattening in an elbow part, roll marks, etc., by inserting a round, straight blank pipe into a space formed between an arc-shaped groove of a semicircular section and a straight groove of a semicircular section of the same radius, and by forcibly moving this blank pipe along the arc-shaped groove.
CONSTITUTION: A core is previously inserted into an elbow-forming point of a round, straight blank pipe 4; this blank pipe 4 is then inserted into a space formed between a semicircular groove 14a of a press-bending die 10 and semicircular grooves 22a, 22a' of rotary bending dies 20, 20'. Then the die 10 is pushed down; hereby, the dies 20, 20' separate to the left and the right, turn around a rotary shaft 50, and then, push and bend the pipe 4 while moving along the inner side wall of grooves 22a, 22a' functioning as the bending fulcrum; thereupon, the pipe 4 is pressed to the groove 14a and is bent into a prescribed shape. After completing the forming work, the shaft 50 is puled away, the die 10 is separated from the die 20, and a shaped product is taken away.
IWADATE TADAO
HORIUCHI MITSUO
KOBAYASHI MASAYOSHI
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