Winding mandrel for the production of reels of web material

Abstract

The winding mandrel includes a substantially cylindrical wall with expandable members for the torsional locking of tubular winding cores. At least one portion of the wall is made of carbon fiber in a polymer resin matrix.

1 - 23 . (canceled) 
     
     
         24 . A winding mandrel for producing reels of web material, comprising a substantially cylindrical wall with expandable members for torsionally locking tubular winding cores on said mandrel, wherein at least a portion of said wall is made of carbon fibers in a polymer resin matrix; said expandable members include a plurality of expandable elements that expand radially outwards of said substantially cylindrical wall by delivery of a fluid under pressure thereto; a plurality of inserts are provided along an axial length of the mandrel, said inserts being connected to a longitudinal duct for the distribution of the fluid under pressure, wherein said duct extends inside said substantially cylindrical wall for at least a part of the axial length of the mandrel; and each of said inserts comprises at least one seat for an expandable element, in fluid connection with said longitudinal duct. 
     
     
         25 . The winding mandrel according to  claim 24 , wherein said expandable elements are pneumatic expandable elements. 
     
     
         26 . The winding mandrel according to  claim 25 , wherein said fluid under pressure is air. 
     
     
         27 . The winding mandrel according to  claim 24 , wherein said expandable elements are deformable due to said delivery of said fluid under pressure so as to protrude from said substantially cylindrical wall; and wherein in absence of said fluid under pressure, said expandable elements are entirely retracted in respective seats so as to not protrude from an outer surface of said substantially cylindrical wall. 
     
     
         28 . The winding mandrel according to  claim 24 , wherein each of said inserts includes at least two seats for corresponding expandable elements arranged in angularly staggered positions around an axis of the mandrel. 
     
     
         29 . The winding mandrel according to  claim 24 , wherein the substantially cylindrical wall is composed of a plurality of tubular portions made of carbon fibers in a polymer resin matrix, and of one or more of said inserts; said tubular portions being connected to one another by said inserts. 
     
     
         30 . The winding mandrel according to  claim 29 , wherein each of said inserts has a substantially cylindrical surface that defines, together with outer surfaces of said carbon fiber tubular portions, a substantially cylindrical surface. 
     
     
         31 . The winding mandrel according to  claim 30 , wherein said substantially cylindrical surface has a substantially continuous coating. 
     
     
         32 . The mandrel according to  claim 31 , wherein said coating comprises at least one layer comprising metal or ceramic. 
     
     
         33 . The winding mandrel according to  claim 29 , wherein each of said inserts includes a central body containing said at least one seat for the expandable elements and axial ends which each form an interfacing surface for attaching said inserts to respective tubular portions. 
     
     
         34 . The winding mandrel according to  claim 33 , wherein said axial ends have an outer surface which is tapered or cylindrical, said outer surface being grooved for anchorage of the tubular portions. 
     
     
         35 . The winding mandrel according to  claim 33 , wherein said central body has a substantially cylindrical outer surface provided with cavities for housing said expandable elements. 
     
     
         36 . The expandable mandrel according to  claim 24 , wherein each of said inserts has an axial through cavity in which a cylindrical member is contained, with an axial hole for passage of said longitudinal duct; coinciding with each of said inserts, said longitudinal duct has at least one outlet for the fluid under pressure; and said cylindrical member is axially attached to the longitudinal duct, forming passages for the delivery of the fluid under pressure coming from said at least one outlet into distribution channels formed in said inserts and in fluid connection with said expandable elements. 
     
     
         37 . The expandable mandrel according to  claim 35 , wherein each of said inserts has an axial through cavity in which a cylindrical member is contained, with an axial hole for passage of said longitudinal duct; coinciding with each of said inserts, said longitudinal duct has at least one outlet for the fluid under pressure; and said cylindrical member is axially attached to the longitudinal duct, forming passages for the delivery of the fluid under pressure coming from said at least one outlet into distribution channels formed in said inserts and in fluid connection with said expandable elements; and said distribution channels comprise a ring-shaped groove and substantially radial passages extending from said ring-shaped groove towards said cavities for housing the expandable elements. 
     
     
         38 . The winding mandrel according to  claim 24 , wherein said expandable elements are formed by volumes of fluid under pressure at least partially contained by a deformable diaphragm. 
     
     
         39 . The mandrel according to  claim 38 , wherein said deformable diaphragm is made of an elastic material. 
     
     
         40 . The winding mandrel according to  claim 35 , wherein each of said cavities for each of said inserts contains an expandable element comprising an elastically deformable wall with an anchorage and sealing lip, fixed in a respective one of said cavities by a locking flange that retains said anchorage and sealing lip inside a groove provided in a corresponding cavity. 
     
     
         41 . The winding mandrel according to  claim 24 , wherein said expandable elements are housed inside corresponding radial holes provided in the substantially cylindrical wall made of carbon fibers in a polymer resin matrix and defining said substantially cylindrical wall of the mandrel. 
     
     
         42 . The winding mandrel according to  claim 24  comprising metal terminal ends, at least one of said metal terminal ends being associated with means for activating the expandable members. 
     
     
         43 . The winding mandrel according to  claim 42 , wherein at least one of said metal terminal ends is made in two parts, a first part attached irreversibly to the mandrel with a hollow body to allow access to inside of the mandrel, and a second part removably attached to said first part. 
     
     
         44 . The winding mandrel according to  claim 24 , wherein said inserts are made of a metallic material.