| 摘要 |
PURPOSE:To cut off economically securely bolts by providing four edge portions quite identical to each other of a pair of upper and lower cutting blades to give interchangeability to a pair of cutting blades and obviate a jam in prouduction or mounting exchange while improving the life of cutting blade. CONSTITUTION:Cutting blades 10, 20 have the thickness produced to have about 3.5 times screw pitch, and the upper cut of root of female screw is located to be on the left side of a surface dividing the upper cutting blade 10 from the lower one 20. Thus, cutting edges 11, 12 are shaped to form point symmetry and the front and back of cutting blade 10 lose the directivity. Also, the cutting edges 11, 12 and 22 are of quite identical shape and the cutting blades 10, 20 are of quite identical shape. Thus, a pair of upper and lower cutting blades 10, 20 have the interchangeability and any jam in production or mounting exchange is obviated while the life of cutting blade can be improved and bolts can be cut off economically and securely.
|
