Pipe bending machine with bending mandrel having a load bearing structure which is particularly resistant to working stresses

Abstract

A pipe bending machine with bending mandrel having a load bearing structure which is particularly resistant to working stresses, comprises an extractor ( 2 ) which is fixed in a rear portion of the pipe bending machine, and mandrel rod ( 13 ) which extends with its longitudinal axis (g), from the extractor beyond a front portion of the machine, where a bending head ( 7 ) which is provided with a die ( 8 ) stresses a pipe (T) to be bent, which is inserted in a mandrel ( 12 ), by a traction resultant force that is transmitted along the mandrel rod ( 13 ) to the extractor ( 2 ) that counteracts with a resultant restraining reaction. The pipe bending machine comprises a load bearing structure ( 1 ) having a profile such that it contains inside the longitudinal axis (g) of the mandrel rod ( 13 ), in such a way that the load bearing structure ( 1 ) is subjected mainly to compression stresses.

1 . A pipe bending machine with bending mandrel having a load bearing structure which is particularly resistant to working stresses, in which an extractor ( 2 ) is fixed in a rear portion of the pipe bending machine and mandrel rod ( 13 ) extends with its longitudinal axis (g), from the extractor beyond a front portion of the machine, where a bending head ( 7 ) which is provided with a die ( 8 ) stresses a pipe (T) to be bent, which is inserted in a mandrel ( 12 ), by a traction resultant force that is transmitted along the mandrel rod ( 13 ) to the extractor ( 2 ) that counteracts with a resultant restraining reaction, characterised in that the pipe bending machine comprises a load bearing structure ( 1 ;  25 ;  26 ) having a profile such that it contains inside the longitudinal axis (g) of the mandrel rod ( 13 ), in such a way that the load bearing structure ( 1 ;  25 ;  26 ) is subjected mainly to compression stresses. 
   
   
       2 . Machine according to  claim 1 , characterised in that said load bearing structure ( 1 ) is prismatic. 
   
   
       3 . Machine according to  claim 1 , characterised in that said load bearing structure ( 25 ) has a round transversal cross section. 
   
   
       4 . Machine according to  claim 1 , characterised in that said load bearing structure ( 26 ) is a reticular structure. 
   
   
       5 . Machine according to  claim 1 , characterised in that said load bearing structure ( 1 ;  25 ;  26 ) has a transversal cross section with a momentum of inertia such that the traction force applied by means of the die ( 8 ) has a direction passing through the centre of inertia of the transversal cross section. 
   
   
       6 . Machine according to  claim 1 , characterised in that said load bearing structure ( 1 ;  25 ;  26 ) rests on a floor through front and rear resting elements ( 4 ,  5 ). 
   
   
       7 . Machine according to  claim 1 , characterised in that said bending head ( 7 ) is slidable mounted in said front end on guides ( 10 ,  10 ) horizontally positioned on a step ( 6 ) resting on the soil transversally to the longitudinal direction of the machine, the bending head ( 7 ) being in contact with an abutment member ( 11 ) in the front portion of the load bearing structure ( 1 ;  25 ;  26 ). 
   
   
       8 . Machine according to  claim 7 , characterised in that the abutment member ( 11 ) forms a transversal sliding coupling.