| 摘要 |
PROBLEM TO BE SOLVED: To develop a measuring instrument mainly for measurement of an internal angle by paying attention to internal angle measurement having few kinds of instruments, with a background wherein, though external angle measurement or inclination measurement, especially inclination measurement, of a V-shape or the like is digitized at present relative to angle measurement, the kinds of instruments is few relative to measurement of the internal angle or the like, and especially in the case related to bending processing or the like of a precision sheet metal or the like, the internal angle measurement is necessary as well as the external angle measurement. SOLUTION: This internal angle exclusive protractor is constituted of two fan-shaped blades 1, 6 formed from an arc side 9 based on an intersection point a, a linear side 8 and angle sides A10. B11. In the protractor, the linear side 8 is moved along an arc slide hole 3 on the arc prolongation, and an angle generated thereby between the linear sides 8, namely the internal angle, is measured. COPYRIGHT: (C)2006,JPO&NCIPI
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