Method for making a building board

Abstract

The invention relates to a method for making a building board, exhibiting a board body which is formed with a gripping stud, and a metal strip which extends from the body and from which are formed gripping elements, which are bent round the gripping stud for mechanical fastening of the strip to the body, as well as a locking element for enabling mechanical joining of the board to similar boards. The method is characterized by preforming the gripping elements of the strip prior to bending them round the gripping stud, and subsequently bending the preformed gripping elements ground the gripping stud, the preforming being such that, as a result of the bending, the preformed gripping elements strike against the gripping stud and thereby undergo a deformation in the opposite direction to the preforming during a final stage of the bending.

1 . A method for making a building board ( 2 ), exhibiting a board body (S) which is formed with a gripping stud ( 24 ), and a metal strip ( 10 ) which extends from the body (S) and from which are formed gripping elements ( 26 ,  28 ) which are bent round the gripping stud ( 24 ) for mechanical fastening of the strip ( 10 ) to the body (S), as well as a locking element ( 12 ) to enable mechanical joining of the board ( 2 ) to similar boards, characterised by preforming the gripping elements ( 26 ,  28 ) of the strip ( 10 ) prior to bending them round the gripping stud ( 24 ), and subsequently bending the preformed gripping elements ( 26 ,  28 ) round the gripping stud ( 24 ), the preforming being such that, as a result of the bending, the preformed gripping elements ( 26 ,  28 ) strike against the gripping stud ( 24 ) and thereby undergo a deformation in the opposite direction to the preforming during a final stage of the bending.  
     
     
         2 . A method according to    claim 1   , wherein the deformation which occurs during said final stage of the bending results in a biasing of the gripping elements ( 26 ,  28 ) of the strip ( 10 ) against the gripping stud ( 24 ).  
     
     
         3 . A method according to    claim 1    or    2   , wherein the strip ( 10 ) is made of a resilient material.  
     
     
         4 . A method according to any one of the preceding claims, wherein the bending of the gripping elements ( 26 ,  28 ) is carried out with the aid of punching means (S 2 , S 3 ) operating essentially at right angles to a principal plane of the building board ( 2 ).  
     
     
         5 . A method according to any one of the preceding claims, wherein the preforming of the gripping elements ( 26 ,  28 ) of the strip ( 10 ) is carried out with the aid of punching means (S 1 ) operating essentially at right angles to a principal plane of the strip ( 10 ).  
     
     
         6 . A method according to claims  4  and  5 , wherein said punching means (S 1 ) achieving the preforming and said punching means (S 2 , S 3 ) achieving the bending are arranged in one and the same punching tool ( 56 ) and are stationary in relation to each other during the preforming and the bending.  
     
     
         7 . A method according to any one of the preceding claims, wherein the deformation which arises during the final stage of the bending consists of a permanent reverse bending as well as a resilient return of the gripping elements ( 26 ,  28 ).  
     
     
         8 . A method according to any one of the preceding claims, wherein there is a range of tolerance (Lmin-Lmax) with respect to the position of the gripping stud ( 24 ), and wherein the degree of preforming of the gripping elements ( 26 ,  28 ) is adjusted to said range of tolerance so that said biasing is obtained over the entire range of tolerance.  
     
     
         9 . A method according to any one of the preceding claims, wherein the gripping stud ( 24 ) is provided with undercut gripping edge parts ( 24   a ).  
     
     
         10 . A method according to any one of the preceding claims, wherein the gripping stud ( 24 ) s provided with non-undercut gripping edge parts ( 24   b ) closest to the strip ( 10 ) as well as undercut gripping edge parts ( 24   a ) adjacent thereto.  
     
     
         11 . A method according to    claim 9    or    10   , wherein the undercut gripping edge parts ( 24   a ) of the gripping stud ( 24 ) exhibit an undercutting angle of 10°-45° in relation to a normal (N) to a principal plane of the building board ( 2 ).  
     
     
         12 . A method according to any one of the preceding claims, wherein the gripping elements ( 26 ,  28 ) of the strip ( 10 ) are preformed to a preforming angle of 15°-90° relative to a principal plane of the strip ( 10 ).  
     
     
         13 . A method according to any one of the preceding claims, wherein the gripping stud ( 24 ) is provided with undercut gripping edge parts ( 24   a ) exhibiting an undercutting angle in relation to a normal (N) to a principal plane of the building board ( 2 ), and wherein the gripping elements ( 26 ,  28 ) are preformed through a preforming angle relative to a principal plane of the strip ( 10 ) which is greater than said undercutting angle.  
     
     
         14 . A method according to any one of the preceding claims, wherein the preforming is achieved by pre-bending each gripping element ( 26 ,  28 ) through a predetermined pre-bending angle at a first point (P 1 ) spaced from a free end of the gripping element ( 26 ,  28 ), and the bending in achieved by bending the gripping element ( 26 ,  28 ) thus preformed round a second point (P 2 ), which is located farther away from said free end than the first point (P 1 ).  
     
     
         15 . A method according to    claim 14   , wherein said second point (P 2 ), round which the bending is carried out, is defined by the gripping stud ( 24 ).  
     
     
         16 . A method according to any one of the preceding claims, wherein the strip ( 10 ) is first moved to a first punch position where the preforming is carried out, and subsequently is moved to a second punch position in which the bending is carried out.  
     
     
         17 . A method according to any one ok the preceding claims, wherein the strip ( 10 ) and the body (S) are not moved together until after the preforming is completed.