Board-to-board connector

A board-to-board connector comprising:

• a first connector, the first connector including first terminals, a first housing having a generally rectangular parallelepiped shape and provided with concave insertion portions, and first reinforcing brackets arranged in the concave insertion portions, each first reinforcing bracket being provided with a first protrusive locking portion, the first locking portion having an outer surface, one half of which is configured as a curved surface having a small radius of curvature, and the other half being configured as a curved surface having a larger radius of curvature or a sloped flat surface;
• and
• a second connector, the second connector including second terminals configured to make contact with the first terminals, a second housing having a generally rectangular parallelepiped shape and provided with convex insertion portions configured fit within the concave insertion portions, and second reinforcing brackets arranged in the convex insertion portions and configured to engage the first reinforcing brackets, each second reinforcing bracket being provided with a second protrusive locking portion configured to engage the first locking portion, the second locking portion having an outer surface, one half of which is configured as a curved surface having a small radius of curvature, and the other half being configured as a curved surface having a larger radius of curvature or a sloped flat surface, both halves being curved or sloped in the same direction;
• wherein one of the first reinforcing bracket and the second reinforcing bracket is formed of a large-width member, and the other is formed of a small-width member.