Mandrel assembly for a tube bending machine

Abstract

A mandrel assembly for a tube bending machine has a mandrel body, a mandrel rod, a series of articulation elements connected to one another and to the mandrel body through respective cylindrical or spherical hinges, and a network of lubricant transport channels formed through the mandrel body and communicating with a lubricant feed passage formed along the mandrel rod. The network of lubricant transport channels has a plurality of lubricant outlet ports arranged on the distal end or on a peripheral surface of the mandrel body. A plurality of through-holes extending along a longitudinal direction of the respective articulation element is formed through each of the articulation elements. The through-holes are configured to convey a lubricant to a front side of an extreme distal articulation element of the series of articulation elements. The extreme distal articulation element has a deflector element.

What is claimed is: 
     
         1 . A mandrel assembly for a tube bending machine, comprising:
 a mandrel body configured to be inserted inside a tube to be bent, the mandrel body comprising a proximal end and a distal end,   a mandrel rod rigidly connected to the proximal end of the mandrel body and configured to support and move the mandrel body,   a series of articulation elements arranged at the distal end of the mandrel body, each articulation element of the series of articulation elements being connected to an adjacent articulation element of the series of articulation elements through a respective cylindrical or spherical hinge, wherein the series of articulation elements comprises an extreme proximal articulation element connected to the distal end of the mandrel body through a cylindrical or spherical hinge, and   a network of lubricant transport channels formed through the mandrel body and communicating with a lubricant feed passage formed along the mandrel rod, the network of lubricant transport channels comprising a plurality of lubricant outlet ports arranged on at least one of the distal end and a peripheral surface of the mandrel body,   wherein a plurality of through-holes extending along a longitudinal direction of the respective articulation element is formed through each of the articulation elements, the through-holes being configured to convey a lubricant to a front side of an extreme distal articulation element of the series of articulation elements, and   wherein the extreme distal articulation element comprises a deflector element fixed to the front side of the extreme distal articulation element, opposite the respective through-holes, the deflector element being configured to radially deflect outwardly the lubricant exiting the respective through-holes.   
     
     
         2 . The mandrel assembly of  claim 1 , wherein each articulation element comprises a central portion through which each articulation element of the series of articulation elements is connected to the adjacent articulation element of the series of articulation elements, and a blanket portion attached to and arranged around the central portion, and wherein the through-holes are entirely formed through the blanket portion. 
     
     
         3 . The mandrel assembly of  claim 1 , wherein the through-holes have a minimum diameter greater than or equal to 4 mm. 
     
     
         4 . The mandrel assembly of  claim 1 , wherein the network of lubricant transport channels comprises a central manifold centrally formed in the mandrel body and directly communicating with the lubricant feed passage, and wherein a plurality of radial channels extending radially toward the peripheral surface of the mandrel body branch off from the central manifold. 
     
     
         5 . The mandrel assembly of  claim 4 , wherein a respective longitudinal channel extending longitudinally toward the distal end of the mandrel body branches off from each of the radial channels and leads to an outside of the mandrel body at the distal end, with a respective lubricant outlet port of the plurality of lubricant outlet ports. 
     
     
         6 . The mandrel assembly of  claim 4 , wherein the radial channels lead to an outside of the mandrel body at the peripheral surface of the mandrel body, with respective lubricant outlet ports of the plurality of lubricant outlet ports. 
     
     
         7 . The mandrel assembly of  claim 6 , wherein the respective lubricant outlet ports lead to at least one surface groove formed on the peripheral surface of the mandrel body.