Patent ID: 7553195

Claim:
A plug, comprising: a first conductor formed as a bar and having a first electrode portion and a first fitting portion; a first insulator outwardly fitted with the fitting portion of said first conductor; a second conductor outwardly fitted with said first insulator and having a second electrode portion and a second fitting portion, said second conductor being isolated from said first conductor by said first insulator; a second insulator outwardly fitted with the fitting portion of said second conductor; a third conductor outwardly fitted with said second insulator and having a third electrode portion and a third fitting portion, said third conductor being isolated from said second conductor by said second insulator; a third insulator outwardly fitted with the fitting portion of said third conductor; wherein the first, second, and third electrodes of said first, second and third conductors are formed with a diameter greater than that of the fitting portions; each of said first, second and third insulators individually have a large diameter portion exposed at least part thereof to the outer face and a small diameter portion having a diameter smaller than that of the large diameter portion; and the fitting portions of said second and third conductors and said fourth conductor are outwardly fitted with the small diameter sections of said first, second and third insulators, respectively, a fourth conductor outwardly fitted with said third insulation portion and having a fourth electrode portion, said fourth conductor being isolated from said third conductor by said third insulator; a fourth insulator attached at least to a portion of the outer face of said fourth conductor; wherein said fourth insulator is formed for engagement with the large diameter portion of said third insulator; and a fifth conductor attached to said fourth insulator.