A barrel nut for securing furniture panels is comprised of a cylindrical body with an external thread extending between its opposite ends. The cylindrical body is arranged for being positioned in a snug fitting hole in a furniture panel. A transverse hole is positioned completely through the cylindrical body and has an internal thread extending between its opposite ends. The transverse hole is arranged for receiving a bolt extending from an adjacent furniture panel. A tool socket is arranged at an outer end of the cylindrical body for receiving a turning tool which can screw the cylindrical body into the snug fitting hole. An alignment mark aligned with the transverse hole is provided on the outer end of the cylindrical body to indicate the position of the transverse hole for facilitating alignment with the bolt.

Device for joining board-shaped elements into one unit with the board-shaped elements extending in a substantially parallel relationship to each other and internally separated by an intermediate gap, has a coupling list abutting adjacent parallel edge portions of the board-shaped elements with members extending towards and engaging with the edge portions. According to the invention, the coupling list includes at least one tension member extending from the side of the coupling list that abuts the edge portions of the board-shaped elements and the tension member is arranged to engage with at least one tightening element extending between the board-shaped elements which when manually rotated is arranged to impose a tightening force unto the tension member causing the coupling list to be pressed against the edge portions of the board-shaped elements.

A connector system substantially rigidly connects a carriage guide rod to a base support structure of a hardcopy apparatus and includes a connector element rigidly fixable to the base support structure. The connector system has a pin which is held in a first bore in the guide rod by a retaining screw in a second bore of the guide rod. The connector system can be adjusted with six degrees of freedom before final fixing. The introduction of a further screw in a threaded part of the first bore permits vertical adjustment of the pin. The connector system can alternatively be used to rigidly secure a printer platen.

In a fastener to join two timbers, there is a concealed coupling bar extending on both sides of the contact area into the timbers and linked to them by two components placed perpendicularly through its extremities. In this invention, one at least of these components is capable of expanding in order to compress the joint, and is actuated perpendicularly to the coupling member.

An interlock secures adjacent panels of ready to assemble furniture in a selected angular relationship and includes a rigid elongated core member including at least a pair of elongated faces thereon disposed in a predetermined angular relationship (usually at right angles) to one another. A plurality of connecting bolts are fixed to the core member and projecting outwardly from each of the elongated faces in predetermined spaced relation to each other along said faces. These connecting bolts are adapted to enter into corresponding bores in the end faces of the panels which are thus secured to the interlock. These connecting bolts each have means thereon for engaging with suitable locking elements, such as cam locks, disposed in the respective bores in the panels whereby the connecting bolts are securely held in the bores with the elongated faces of the core member is close abutting relation to the respectively associated end faces of the panels.