DEVICE AND METHOD FOR FORMING COTTER PIN HOLE OF BOLT, ETC.

摘要

PURPOSE:To punch and form open chamfering parts of a cotter pin and a cotter pin hole by arranging a bolt holding tool, an upper punch of a double construction of an outer punch having a tapered tip part containing an inner punch and a lower punch having a tapered tip part faced to each other to punch and form open chamfering parts of a cotter pin and a cotter pin hole. CONSTITUTION:The lower diameter part of the thread of a bolt 1 is restrained and fixed by the holder and pressed by upper and lower punches 8, 14 arranged relatively at the forming position of a cotter pin 3 in the axial direction and the open chamfering parts 4a, 4b of the cotter pin hole 3 are formed by the tapered parts 12, 16 of each tip. Continuously, since an inner punch 10 is struk in through the inner peripheral holding hole 11 of an outer punch 9 in the upper punch 8 to punch and form a cotter pin hole 3, the open chamfering parts 4a, 4b of the cotter pin hole 3 can be punched and formed without preparing another stage and the working manhour is reduced and the working time, too, is shortened.