FIXED STRUCTURE

PROBLEM TO BE SOLVED: To provide a fixed structure of a casing suitable for assembly when two cases are coupled together and for costs. SOLUTION: First engagement protrusions 40a, 40b have respective engagement pawls 41a, 41b. The engagement protrusions 40a, 40b have respective engagement holes 42a, 42b. Second engagement protrusions 51a, 51b have respective engagement pawls 52a, 52b. A circuit board 60 is provided with a through hole 61. The engagement pawls 41a, 51b are engaged in the through hole 61. When an upper case 5 is pushed in, inclined faces 54a, 54b are made to abut against the inclined faces 71, 72 of an engagement piece 70. As the upper case 5 is further pushed in, the inclined faces 54a, 54b are pushed by the inclined faces 71, 72 toward the first engagement protrusions 40a, 40b, and the engagement pawls 52a, 52b enter the engagement holes 42a, 42b, whereby the first engagement protrusions 40a, 40b are engaged with the second engagement protrusions 51a, 51b. COPYRIGHT: (C)2007,JPO&INPIT