Winding group and method for winding paper around a core to make a log

1) A Winding group for winding paper around a core for making a log, comprising:

• in an upstream position, means for transporting and introducing said core into a channel defined at a top by an upper winding roller supplied from above with said paper directed towards said channel and at a bottom by a cradle member associated downstream with a lower winding roller, said winding group comprising a third oscillating roller arranged above said lower winding roller, said three rollers having respective axes parallel to each other and perpendicular to the forward movement of said paper and cooperating downstream of said channel to wind said paper around said core to make said log, further being provided cyclic means for tearing said paper moving forward on said upper winding roller to identify a final edge and an initial edge, as well as means to cause said initial edge to wind on said core) introduced into said channel, said cyclic means for tearing said paper comprising a rod member rotating around a pin and provided with a head for cyclic cooperation with said upper winding roller for tearing said paper, wherein said head at least in proximity to said upper winding roller has a greater peripheral speed with respect to that of said upper winding roller to tear said paper upstream of said head.