| 摘要 |
PROBLEM TO BE SOLVED: To secure the sealability, and to facilitate the assembling, and to facilitate the various color arrangement by ultrasonic-welding a fixing part of each key top block to an edge of each window hole of a case. SOLUTION: A case 11 is formed with circular window holes 12 corresponding to key tops 21 of a key top block 20, and the back surface side of the edge of the holes 12 are respectively formed with a recessed fixing surface 14 corresponding to the fixing part 27. Each top 21 of the block 20 is inserted into each hole 12 of the case 11, and the surface side of the fixing part 27 is ultrasonic-welded to the surface 14 over the whole circumference without a clearance, and the block 20 is fixed to the case 11. Consequently, the surface side of the fixing part 27 of the block 20 and the surface 14 of the case 11 are tightly fitted to each other so as to integrate the block 20 and the case 11 with each other, and the holes 12 are perfectly closed. The number of part items can be reduced by the integration, and while since the holes 12 are previously closed, the assembling work is facilitated, and the sealability is secured, and various color arrangement of the top 21 and the case 11 and change thereof are facilitated. |
