Rotary head for brush cutters

A rotary head for brush cutters comprising:

• a lower shell having a rotation axis and comprising one or more pins, each of which is configured to hinge, in use, a respective blade;
• wherein the lower shell comprises a hub, which is configured to be rotated about said rotation axis;
• said hub having a plurality of respective grooves;
• wherein the rotary head comprises a ring nut and does not engage with a spring wherein the ring nut comprises a plurality of radial teeth, each of the plurality of radial teeth being inserted within a respective groove of said hub;
• the ring nut being rotatable about the rotation axis from a first working configuration to a second blade-change working configuration, and vice versa;
• wherein the rotary head comprising positioning units for interference fitting said ring nut in a predetermined angular position relative to said lower shell;
• wherein one or more positioning units are between the ring nut and the lower shell;
• wherein said positioning units between the ring nut and the lower shell comprise a first inner ring, connected to said ring nut, and a second outer ring connected to said lower shell;
• wherein said inner ring comprises an annular main body, which is provided, on the inside, with radial teeth and, on the outside, with a plurality of bulges;
• and
• wherein said outer ring comprises an annular main body having a smooth outer profile and a shaped inner profile;
• said shaped inner profile being configured to be engaged by said bulges of said inner ring.