Wood element and a method for the production and the use of such a wood element

Abstract

The object of the invention is an element composed of wood pieces ( 2 a , 2 b , 2 c ). Glueing compression is carried out by bands ( 4 ) fitted permanently in the element in order to reduce tension stresses or at least to bind the pieces before the glue gets hard. In the middle portions ( 2 c ) of the element waste wood of the wood industry is used.

1 . An oblong element, such as a joist, pillar, lattice or slab, mainly composed of wood like pieces ( 2   a ,  2   b ,  2   c ), for instance of sawn wood, LVL, LSL, at least partly by means of glue ( 6 ) and manufactured in a special position and moved over to the site of use,  
       characterized in that 
 the compression required by glueing is produced, at least mainly by means of a band or a film ( 4 ) tightened about the glue lines ( 6 ) of the wood pieces ( 2   a ,  2   b ,  2   c ),  
 at least a part of bands or film ( 4 ) are fitted to work also as transportation protection of element or elements, or as an element holding pieces ( 2   a ,  2   b ,  2   c ), together during transportation.  
 
     
     
         2 . An element according to  claim 1  characterized in that as to its geometrical shape the element is special, having a longitudinal section arched in two directions or having holes, or having a box shaped cross section, or there are cantilevers in the joist.  
     
     
         3 . An element according to  claim 1  or  2  characterized in that 
 in the element at least one band ( 4 ) is thin, width/thickness of cross-section >5, most advantageously >10, and the element made for instance of plastic like flexible material, the relative elongation of which in binding position is >1%, most advantageously >2%,  
 that most advantageously the band can be tightened and bound in itself by means of welding, whereby at least in one point, most advantageously in the element point critical in regard to fracture by tension, which is 0.05 MPa.  
 
     
     
         4 . A method to produce an element according to  claim 1 ,  2  or  3  affected by unusual stresses, due to the geometrical shape of the element, as discontinuation and splicings, or by critical stresses, especially tension stresses, directed on the wood or the glue line due to the element curvature, characterized in that 
 at least a part of the bands are fitted permanently in the element and  
 the bands are fitted to reduce tension stresses by means of their arrangement and tightening and in that way to prevent them from causing fractures.  
 
     
     
         5 . Utilization of waste wood, such as short stumps and poor quality timber, arising in a wood product factory, as a saw mill, for the manufacture of an element according to  claim 1 ,  2  or  3 , characterized in that the waste wood is used in the element middle portion ( 2   c ).