Fastening element for use in mining and tunnel construction

Abstract

A fastening element for use in mining a tunnel construction, has a base body ( 12; 32; 42 ); and a plurality of weakenings ( 14, 15; 34, 35; 44, 45; 54 ) provided on an outer surface ( 13; 33; 43; 53 ) of the base body and a cross-section of which provides a break-off location and which are formed as a spiral extending along a longitudinal extent of the base body ( 12; 32; 42; 52 ).

1 . A fastening element for use in mining and tunnel construction, comprising a base body ( 12 ;  32 ;  42 ); and a plurality of weakenings ( 14 ,  15 ;  34 ,  35 ;  44 ,  45 ;  54 ) provided on an outer surface ( 13 ;  33 ;  43 ;  53 ) of the base body, each formed as a spiral extending along a longitudinal extent of the base body ( 12 ;  32 ;  42 ;  52 ), a cross-section of the weakenings defining a weakened cross-section of the base body, thereby providing a break-off location of the base body. 
     
     
         2 . A fastening element according to  claim 1 , wherein at least two weakenings ( 14 ,  15 ;  34 ,  35 ;  44 ,  45 ) have different directions of rotation. 
     
     
         3 . A fastening element according to  claim 1 , wherein at least two weakenings ( 14 ,  15 ) have different gradients. 
     
     
         4 . A fastening element according to  claim 1 , wherein the base body ( 32 ;  42 ) is tubular. 
     
     
         5 . A fastening element according to  claim 1 , wherein at least one of the plurality of weakenings ( 34 ,  35 ;  44 ,  45 ) is formed as a recess provided on the outer surface ( 33 ;  43 ) of the base body ( 32 ;  42 ). 
     
     
         6 . A fastening element according to  claim 5 , wherein the recess has a depth (T) measured from the outer surface ( 33 ) of the base body ( 32 ) and corresponding to 0.05 to 0.3 times of an outer diameter (D) of the base body ( 32 ). 
     
     
         7 . A fastening element according to  claim 1 , wherein the plurality of weakenings comprises weakenings extending in a same direction and circumferentially offset relative to each other. 
     
     
         8 . A fastening element according to  claim 1 , wherein a cross-section of the weakenings ( 34 ,  35 ) is formed by a partial thermal treatment of the base body ( 32 ). 
     
     
         9 . A fastening element according to  claim 1 , wherein a cross-section of the weakenings ( 44 ,  45 ) is formed by a partial deformation of the base body ( 42 ;  52 ). 
     
     
         10 . A fastening element according to  claim 9 , wherein the weakenings ( 54 ) are formed by squirting, with produced depressions ( 56 ) extending in direction of a middle point of a cross-section of the base body ( 52 ).