Winding rod for reels of web material and a winding machine using said rod

Abstract

The winding rod (A) comprises a longitudinal body ( 15 ) extending from a first end to a second end of the rod. It also comprises expandable elements ( 33 ) distributed around a longitudinal axis of the longitudinal body and at least one pressurization circuit for expanding said expandable elements. The expandable elements ( 33 ) are distributed in a first group of expandable elements and a second group of expandable elements, arranged in end portions of the longitudinal body, which also comprises an intermediate portion devoid of expandable elements.

1 . A winding rod for winding reels of web material, the winding rod comprising:
 a longitudinal body extending from a first end to a second end,   expandable elements distributed around a longitudinal axis of the longitudinal body;   at least one pressurization circuit for expanding said expandable elements, wherein the expandable elements are distributed in a first group of expandable elements and a second group of expandable elements, arranged in end portions of the longitudinal body, said longitudinal body comprising an intermediate portion devoid of expandable elements, the longitudinal body of the winding rod comprising a first shaft and a second shaft and a tubular element placed between the first shaft and the second shaft and torsionally and axially constrained to said first shaft and said second shaft, so as to form said longitudinal body, the first shaft and the second shaft being fitted respectively with a first longitudinal passage for a pressurization fluid and a second longitudinal passage for a pressurization fluid, said first longitudinal passage and said second longitudinal passage being fluidly coupled to the first group of expandable elements and the second group of expandable elements, respectively.   
     
     
         2 . A winding rod according to  claim 1 , wherein the intermediate portion has a cylindrical outer surface with a diameter substantially corresponding to a diameter of the end portions in which the expandable elements are located. 
     
     
         3 . A winding rod according to  claim 1 , wherein said at least one pressurization circuit comprises a fluid connection from the first group of expandable elements to the second group of expandable elements and said at least one pressurization circuit has at least one pressurization and de-pressurization valve, placed at one of said first end or second end of the longitudinal body, by means of which both the first group of expandable elements and the second group of expandable elements can be pressurized. 
     
     
         4 . A winding rod according to  claim 1 , wherein said expandable elements are in a form of laths extending parallel to the longitudinal body of the winding rod. 
     
     
         5 . A winding rod according to  claim 1 , further comprising housings for the first group of expandable elements and housings for the second group of expandable elements. 
     
     
         6 . A winding rod according to  claim 5 , wherein said housings are in a form of longitudinal recesses distributed around the longitudinal axis of the longitudinal body of the winding rod, and extending parallel to said longitudinal axis. 
     
     
         7 . A winding rod according to  claim 6 , wherein each of said longitudinal recesses contains an air chamber, wherein inflation of said air chamber causes a radial expansion of the expandable elements. 
     
     
         8 - 9 . (canceled) 
     
     
         10 . A winding rod according to  claim 1 , wherein the first longitudinal passage and the second longitudinal passage are flow connected to one another by means of an intermediate conduit extending longitudinally inside an intermediate portion of the winding rod. 
     
     
         11 . A winding rod according to  claim 1 , wherein said tubular element is made of carbon fibers. 
     
     
         12 . A winding rod according to  claim 1 , wherein the first longitudinal passage and the second longitudinal passage are fluidly coupled by means of a conduit extending longitudinally inside the tubular element placed between the first shaft and the second shaft. 
     
     
         13 . A winding rod according to  claim 1 , wherein the first group of expandable elements is mounted on the first shaft and the second group of expandable elements is mounted on the second shaft. 
     
     
         14 . A winding rod according to  claim 1 , wherein the first group of expandable elements and the second group of expandable elements are mounted at respective ends of the tubular element. 
     
     
         15 . A winding rod according to  claim 12 , further comprising a single air chamber for each group of expandable elements, wherein inflation of said single chamber causes a radial expansion of respective expandable elements. 
     
     
         16 . A winding rod according to  claim 1 , wherein the intermediate portion devoid of expandable elements extends for at least two-thirds of the overall length of the winding rod, and preferably for at least three-quarters of said overall length. 
     
     
         17 . A winding rod for winding reels of web material, the winding rod comprising:
 a longitudinal body extending from a first end to a second end,   expandable elements distributed around a longitudinal axis of the longitudinal body;   at least one pressurization circuit for expanding said expandable elements, the expandable elements being distributed in a first group of expandable elements and a second group of expandable elements, arranged in end portions of the longitudinal body, said longitudinal body comprising an intermediate portion devoid of expandable elements, the intermediate portion having a cylindrical outer surface with a diameter substantially corresponding to a diameter of the end portions in which the expandable elements are located, a first longitudinal passage for a pressurization fluid and a second longitudinal passage for a pressurization fluid being provided, said first longitudinal passage and said second longitudinal passage being fluidly coupled to the first group of expandable elements and the second group of expandable elements respectively, the first longitudinal passage and the second longitudinal passage being flow connected to one another by means of an intermediate conduit extending longitudinally inside said intermediate portion of the winding rod.   
     
     
         18 . A winding machine or re-winding machine comprising members for winding a web material, a feed path for the web material and at least one winding rod, said at least one winding rod comprising a longitudinal body extending from a first end to a second end, expandable elements distributed around a longitudinal axis of the longitudinal body and at least one pressurization circuit for expanding said expandable elements, wherein the expandable elements are distributed in a first group of expandable elements and a second group of expandable elements, arranged in end portions of the longitudinal body, said longitudinal body comprising an intermediate portion devoid of expandable elements, the longitudinal body of the winding rod comprising a first shaft and a second shaft and a tubular element placed between the first shaft and the second shaft and torsionally and axially constrained to said first shaft and said second shaft, so as to form said longitudinal body, the first shaft and the second shaft being fitted respectively with a first longitudinal passage for a pressurization fluid and a second longitudinal passage for a pressurization fluid, said first longitudinal passage and said second longitudinal passage being fluidly coupled to the first group of expandable elements and the second group of expandable elements, respectively. 
     
     
         19 . A machine according to  claim 18 , wherein the winding rod is a peripheral winding means. 
     
     
         20 . A winding rod according to  claim 2 , wherein said at least one pressurization circuit comprises a fluid connection from the first group of expandable elements to the second group of expandable elements and said at least one pressurization circuit has at least one pressurization and de-pressurization valve, placed at one of said first end or second end of the longitudinal body, by means of which both the first group of expandable elements and the second group of expandable elements can be pressurized. 
     
     
         21 . A winding rod according to  claim 2 , wherein said expandable elements are in a form of laths extending parallel to the longitudinal body of the winding rod. 
     
     
         22 . A winding rod according to  claim 3 , wherein said expandable elements are in a form of laths extending parallel to the longitudinal body of the winding rod. 
     
     
         23 . A winding rod according to  claim 2 , further comprising housings for the first group of expandable elements and housings for the second group of expandable elements. 
     
     
         24 . A winding rod according to  claim 23 , wherein said housings are in a form of longitudinal recesses distributed around the longitudinal axis of the longitudinal body of the winding rod, and extending parallel to said longitudinal axis. 
     
     
         25 . A winding rod according to  claim 24 , wherein each of said longitudinal recesses has an axial length that is less than half an axial length of the rod, and each of said longitudinal recesses is divided into two groups of longitudinal recesses, a first of said two groups of longitudinal recesses extending from one of said first end and second end and another one of said two groups of longitudinal recesses extending from another one of said first end and second end, a central portion of the winding rod being devoid of said longitudinal recesses.