Abstract: A coupling device includes one or more coupler members each having a strut member engaged into a beam, a catch received in a chamber of the coupler member and having an inclined outer structure inclined from one side toward the other side, for allowing the one side of the catch to be easily engaged into the chamber of the coupler member. A fastener may be engaged through the coupler member, and threaded with the catch, in order to move the catch relative to the strut member, and to selectively force the strut member to engage with and to lock the beam.