FI85116B - Three-part branching construction - Google Patents

Description

85116

Treble The connecting structure

The present invention relates to a three-pronged joint structure for load-bearing parts made of wood veneer by lamination. In particular, this structure is useful in furniture frame structures, but the invention can also be applied to similar other load-bearing structures made of veneer-like layers as a lamination technique or the like, such as a building technique.

In the following, the invention will be explained mainly in connection with the furniture structure.

For furniture frames, it is known to make three-branch joints, mainly T-branch joints or joints close to this shape, made of wood veneer laminated boards. The thickness of each pre-laminated sheet corresponds to about half the thickness of the claw of the desired joint. Said plates are glued on one surface and the plates are placed in a three-part heating press corresponding to the T-shape in question. In this case, the upper half of the opposite shoulder arms forming the shoulder portion of the T-joint is formed of a substantially straight plate, while the plates forming the lower half of the shoulder arms are bent to protrude parallel to the T-leg split portion, and said half halves are joined to each other. The T-junction thus formed inevitably forms a central region which remains open due to the limited bending capacity of the laminates.

In known structures, the area of said T-junction is left open. However, this solution has a strength technical problem that occurs in the junction areas of the laminate halves of the branches. These areas do not want 2 85116 to last, but the gluing that connects the halves tends to open up over time. Efforts have been made to reduce the problem with mechanical joints connecting the halves, such as bolting, but no substantial improvement has been achieved. The perforation required for bolting may even worsen the situation, resulting in structural fractures.

The known structure also requires a manufacturing technique in which the branch halves have to be formed from prefabricated laminates, because the opening remaining at the T-junction does not allow the entire part to be manufactured as a single-stage lamination. Post-gluing joining the parts does not give the same uniform structure as single-stage lamination, which contributes to the strength of the structure.

We have sought a solution to these problems with a filling piece to be placed in the opening of the T-junction, which would be laminated as part of the finished structure. With such a filler, the manufacturing technique can be simplified to the above-mentioned single-phase lamination, whereby the strength advantages provided by the manufacturing technique are also involved. The filling piece has been found to be the most suitable for a wood veneer similar to the molded part made by laminating the structure, which has been machined to fit the shape of the opening. In particular, it has been found advantageous for this shaped or filling body if it is made of two parts whose lamination directions are perpendicular to each other, and if this body is placed in the opening so that the lamination directions of the body parts substantially correspond to the lamination directions of the three-branched parts. It is advantageous to connect the parts of the shaped body to each other by means of a notched joint.

Details of the structure according to the invention will become apparent from the accompanying drawing.

i; 3 85116

The drawing shows a part of a body with a substantially rectangular T-joint. The body has opposite branches, shoulder branches 1 and 2, and a branch projecting perpendicular to them, a leg branch 3. Each branch consists of substantially equal material-thickness parts 1 ', 1' '; 2 ', 2' 'and 3', 3 '', each of which continues into an adjacent branch. In the embodiment shown, the upper parts 1 'and 2' of the shoulder arms are substantially straight, while their lower parts 1 · · and 2 '* continue 90 ° bent into the leg branch portions 3' and 3 ''.

The area left empty by these material thicknesses in the bending or junction area is filled with a shaped body 4 which has been machined to correspond to the natural shape of the opening. This shaped or filling piece 4 is made of two parts 4 'and 4' 'laminated from a veneer similar to what is otherwise made of the body piece. The parts of the filling piece are connected to each other so that the direction of lamination of the veneers in the second piece is perpendicular to the veneer direction of the second piece. It is advantageous to connect the parts to each other by a notched joint.

Said shaped or filling piece 4 is prefabricated and machined to suit the respective three-branch joint shape. In the manufacture of said three-pronged joint, glued veneer bundles are formed to form the lower parts 1 '' and 2 '' of the shoulder branches and the parts 3 'and 3' 'of the leg branch in a heating press whose jaw parts facing the leg branch are close to their pressing position. The lower parts 1 '' and 2 '' of the shoulder arms are then turned apart and pressed against the respective jaw parts of the press. The filling piece 4 is placed in place, after which the upper side 1 ', 2' of the correspondingly glued veneer bundle is placed in the press. The press is then closed and the heating is switched on by laminating.

Claims (4)

4 85116 man for curing. The compression heating time is questionably a few minutes from the room parts. The result is a fully laminated body for the branches, which also has a closed branch connection area which cooperates as well as possible with the branch parts to distribute the stresses between them. Due to the laminated structure of the filler, no peeling or aging tests have been observed in the stress and aging tests, which may occur if, for example, a part made of a single piece of wood is used as the filler. The accompanying drawing shows by way of example a three-pronged joint consisting of a substantially rectangular T-joint. Also within the scope of the invention are also mutually modified three-pronged joints, in which, for example, the divider part 3 protrudes from the shoulder parts 1 and 2 at an angle other than the 90 ° angle shown. Furthermore, the shoulder parts 1 and 2 may be at an angle other than 180 ° to each other. It is also possible that the thicknesses of the branches differ from each other. Each structure acquires its own natural shape, the area to be filled in the middle of the branch area, to which the shape of the filling piece must be adapted. A three-pronged joint structure for laminating a support part made of wood veneer, in particular for a furniture frame, in which at least part, preferably about half of the laminate layers of each branch (1,2,3) are bent to continue as part of an adjacent branch, characterized in that a glued-shaped filler consisting of laminated wood veneer layers (4). A three-pronged joint structure according to claim 1, characterized in that the filler body consists of two parts (4 ', 4' ') in which the lamination direction of the veneers is perpendicular to each other, closely following the associated branch (1', 2 '; 3', 3 '') veneer direction. Three-pronged connection structure according to Claim 2, characterized in that the parts (4 ', 4' ') of the infill are connected to one another by a notched connection. Three-pronged joint structure according to one of the preceding claims, characterized in that it is produced in one heat pressing step. 6 85116