Patent attributes
The two coil spring terminals have the structure of double coil spring terminal including a small diameter coil spring terminal and a large diameter coil spring terminal. In this case, a terminal holder is provided with a clamping portion for clamping the large diameter coil spring terminal between the terminal holder and an internal circuit board. Specifically, the terminal holder is formed, in an upper end portion of its outer peripheral surface, with an annular groove which is adapted to be engaged with a small diameter portion formed in an upper end portion of the large diameter coil spring terminal. This omits fixation of the large diameter coil spring terminal to the internal circuit board, and necessity of soldering the two coil spring terminals respectively to the internal circuit board as a conventional art, enhancing mounting workability of the terminal holder.