Abstract: A locking device for assembling tubular frame components of exhibit framework structures and the like, including an elongated box-like housing sized to be received in a cavity of one of the frame components, the housing having an open coupling end provided with protruding spaced apart coupling ear formations integral with the housing adjacent top and bottom walls thereof and flanking the opening of said coupling end. An elongated thin spring-metal interlocking latching member is movable in the housing by a cam and has a recurved hook formation on one end thereof spanning the space between and aligned with the ear formations.