Unwinder of a thin ply product wound on a roll, comprising a first roll-holder assembly equipped with a first unwinding rod for a respective roll, on which the roll is adapted to be supported, and which has an axis of rotation transversal to the direction of movement of the ply unwound from the roll, a second roll-holder assembly equipped with a second unwinding rod of a respective roll, on which the roll is adapted to be supported, said second rod being parallel to said first unwinding rod of the first roll-holder assembly, said second roll-holder assembly facing said first roll-holder assembly in an unwinding zone, a ply splicing assembly placed above said first and second facing roll-holder assemblies, a ply accumulation unit to allow automatic switching between a roll being unwound in one said roll-holder assembly and a spare roll provided in the other roll-holder assembly, a system for the lateral movement of each of said unwinding rods with respect to said unwinding zone, from said unwinding zone to a loading zone wherein said rolls are outside said winding zone to facilitate loading the rolls into the respective roll-holder assemblies, wherein said splicing assembly can be moved from a working position above the two said roll-holder assemblies in said unwinding zone, to a working position above an extracted roll assembly in the loading zone, to allow preparation for splicing of the leading edge of the ply wound on the spare roll.

An unwinder for unwinding reels of paper includes a supporting structure partially closed and defining an internal space suitable for unwinding at least one reel; the supporting structure includes: a first lateral support; a second lateral support spaced from the first support; a crosspiece interposed above between the first and the second support defining with the first support and second support the partially closed structure; the unwinder further includes: a first axial unwinding system placed at the first support and configured to axially unwind a first reel; a second axial unwinding system placed at the second support and configured to unwind a second reel; a joining device placed at the crosspiece and configured to make a joint between a first ply belonging to the first reel and a second ply belonging to the second reel to perform a reel exchange.