Area contact truss strut joint

Abstract

A strut joint of a truss features a contact trough on an inner chord face being in an area contact with a rotationally symmetric strut end surface having a contact radius of at least half a strut height. The rotation axis of the strut end surface and the trough is substantially perpendicular to the struts protrusion direction and the chord's protrusion direction. The area contact provides for snug contact irrespective deviations from a predetermined strut joint angle between strut end and chord. An optional interposing structure may extend the area contact in between two opposite strut end surfaces of a single strut joint.

1 . A strut having a rotationally symmetric end surface, said rotationally symmetric end surface having a contact radius of at least half of a height of a strut side face and having an end surface angle of up 180 degrees, wherein a rotation axis of said end surface is substantially perpendicular to said strut side face.  
   
   
       2 . The strut of  claim 1 , wherein said end surface is in an area contact with a trough on an inner face of a chord, said end surface and said trough being part of a strut joint, and wherein said strut is in a strut joint angle to said chord.  
   
   
       3 . The strut of  claim 2 , wherein said strut contacts a second of said strut in a strut contact line.  
   
   
       4 . The strut of  claim 3 , wherein said end surface angle is selected such that said strut contact line is within said end surface.  
   
   
       5 . The strut of  claim 3 , wherein a number of said strut joint are part of a truss and wherein a number of said strut of said truss have said end surface angle substantially equal and selected in conjunction with a maximum and a minimum of said strut joint angle and selected in conjunction with a trough angle such that said number of said end surfaces extend at least up to a peripheral edge of a respective of said trough and a respective of said strut contact line.  
   
   
       6 . The strut of  claim 1 , wherein said end surface is in contact with an interposing trough surface of an interposing structure.  
   
   
       7 . The strut of  claim 1  being made of wood.  
   
   
       8 . A chord comprising a rotationally symmetric contact trough on a face of said chord, said contact trough being rotationally symmetric with respect to a trough axis, said trough axis being substantially perpendicular to a protrusion direction of said chord.  
   
   
       9 . The chord of  claim 8  being made of wood and wherein said chord has interrupted chord grains in a vicinity of said contact trough.  
   
   
       10 . The chord of  claim 8  being made-of wood and wherein said chord has substantially continuous chord grains in a vicinity of said contact trough.  
   
   
       11 . The chord of  claim 8 , wherein said trough is in an area contact with an end surface of a strut, said end surface and said trough being part of a strut joint, and wherein said strut is in a strut joint angle to said chord.  
   
   
       12 . The chord of  claim 8 , further comprising an interposing structure adjacent said contact trough and on top of said chord face, said interposing structure having a contact surface corresponding to and extending from said contact trough.  
   
   
       13 . The chord of  claim 8 , wherein said contact trough is provided by an interposing structure placed on said chord face.  
   
   
       14 . A truss having a strut joint comprising a strut having a rotationally symmetric end surface in an area contact with a rotationally symmetric trough on an inner chord face, said end surface and said trough having a rotation axis substantially perpendicular to a symmetry plane of said truss, and wherein said strut is in a strut joint angle to said chord.  
   
   
       15 . The truss of  claim 14 , wherein said end surface has a contact radius of at least half of a height of strut side face and an end surface angle of up 180 degrees.  
   
   
       16 . The truss of  claim 14 , wherein said strut contacts a second of said strut in a strut contact line within said strut joint.  
   
   
       17 . The truss of  claim 16 , wherein said end surface angle is selected such that said strut contact line is within said end surface.  
   
   
       18 . The truss of  claim 16 , wherein a number of said strut joint have said end surface angle substantially equal and selected in conjunction with a maximum and a minimum of said strut joint angle and selected in conjunction with a trough angle such that said number of said end surfaces extend at least up to a peripheral edge of a respective of said trough and a respective of said strut contact line.  
   
   
       19 . The truss of  claim 14 , wherein said chord is made of wood and wherein said chord has interrupted chord grains in a vicinity of said contact trough.  
   
   
       20 . The truss of  claim 14 , wherein said chord is made of wood and wherein said chord has substantially continuous chord grains in a vicinity of said contact trough.  
   
   
       21 . The truss of  claim 14 , further comprising an interposing structure adjacent said contact trough and on top of said chord face, said interposing structure having a contact surface corresponding to and extending from said through, and wherein said contact surface is in an area contact with said end surface.  
   
   
       22 . The truss of  claim 14 , wherein said trough is provided by an interposing structure placed on said inner chord face.