Abstract: A lock joins two bodies together. The first body has a first hole and the second body has a second hole, and the lock includes a rail on the first body adjacent to the first hole, two spaced-apart cradles movable on the rail, a spring between and attached to the two cradles that urges the two cradles toward each other, a plunger that moves perpendicular to a longitudinal axis of the spring through the first hole, where the plunger has a locking end that moves into the second hole to join the bodies together. The lock has two levels that are each hinged to a different one of the cradles and to the plunger and that cause the locking end of the plunger to retreat from the second hole to unlock the bodies when the cradles move toward each other.