Abstract: The invention provides a joiner for joining together panel members in edge to edge relationship, the joiner having a joining element which defines a housing which is adapted to engage within a cavity in one of the panel members, and another joining element which at one end has a cavity engaging portion adapted to engage within a cavity in the other panel member, and an elongate shaft which extends away from portion and which is provided with a plurality of teeth spaced along the length thereof so as to form a rack portion, the two joining elements being slideable relative to one another by drive means which includes a driven worm gear in mesh with the rack portion, and a worm gear actuator arranged, upon rotation thereof, to drive the driven worm gear whereby rotary motion of the worm actuator is translated into linear motion only of the shaft.