Single cam operated attachment device

1. Technical Field A fastening device (F) with first () and second sides () attaches a first device () to a mounting rail () of a second device (). A top section () for mounting the first device extends from the first or second sides. The sides are adapted to removably clamp about the rail. A clamping member () extends between the first and second sides. An extended end () of the clamping member extends through the first side, and an opposing end () is coupled with the second side. The clamping member extended portion () is movably coupled to a single cam member () operably mounted with the first side for drawing the sides closer together into a clamping position () to mate the sides with the rail.