Abstract: An automobile seatback subassembly for mutually securing an automobile seat and seat back, and comprising a complimentary pair of mutually interlocking members including an elongated member having a slide with a notched profile intermediate leading and trailing ends thereof, and a channel member comprising a wall arrangement defining an open ended channel for receiving a predetermined maximum length of the mounting member, in axial inter-fitting relation therein. The channel member includes a rotationally biased eccentric cam arranged on a pivot located adjacent the channel with a radially outermost extent of the cam normally biased into inter-fitting relation within the channel in transverse register with the notched profile of the elongated mounting member when the latter is inter-fittingly arranged within the channel. The cam is operably rotatable out of that interfering relation in order to permit the insertion and the withdrawal of the mounting member in the manner described below.