| 摘要 |
PROBLEM TO BE SOLVED: To enhance the practical value of a cover having an engaging groove, capable of opening/closing without breaking the edge of the engaging groove even when only a small number of coins are on hand. SOLUTION: A battery cover 6 consists of an edge surface part 12 and a body part 14. A first engaging groove 18 extending in a first width W1 and a second engaging groove 20 extending in a second width W2 are formed on the surface 16 of the edge surface part 12. The bottom surface 1802 of the first engaging groove 18 is formed in a circular arc shape by a first radius of curvature R1, and the bottom surface 2002 of the second engaging groove 20 is formed in a circular arc shape by a second radius of curvature R2 which is smaller than the first radius of curvature R1 on the bottom surface 2002. The second engaging groove 20 is formed so as to extend in parallel to the extending direction of the first engaging groove 18, in the center in the width direction of the first engaging groove 18. |
