A method and plant for the manufacture of lattice trusses from wooden beams

摘要

Lattice trusses are manufactured from straight wooden elements (10, 20, 21, 31-34), which have been given pre-selected lengths and end-shapes so that they can be butt jointed together in a plane in the truss configuration. Nailing plates (2) are applied over the joins between said elements and driven into the elements so as to fasten the elements together. Nailing plates (2) are applied on each side of the truss. Prior to adjoining the elements (10, 20, 21, 31-34), markings (1) that indicate the positions in which the nailing plates (2) shall be mounted on the upper side of the truss are drawn on one side of the elements that will face upwards. The position marking (1) is designed to provide clear information relating to position, orientation and size of respective nailing plates. Plant (46) for manufacturing the elements of such trusses includes drawing devices (49) which draw the markings (1) on said elements in accordance with a pre-set program (47) as the elements are manufacture, or subsequent to the manufacture of said elements. Sensors (48) can then detect, e.g., one end of the element as a reference, so that the element can be correctly marked.