Unit for applying a label on a relative article

A labeling unit movable along a given path for receiving labels to be applied on relative articles, said labeling unit comprising:

• a hollow receiving member having a lateral wall adapted to receive a relative label, extending around an axis transversal to said path and comprising a suction portion provided with through holes;
• a suction pneumatic device connected to said holes through the inside of said receiving member and which can be activated to retain a label on the outer surface of the lateral wall of said receiving member by suction;
• and
• a hollow distributor member, which is coaxially arranged inside said receiving member in a position interposed between said suction device and said holes, is provided with at least two angularly spaced opening sections having, in a direction parallel to said axis, different heights correlated to the heights of different labels to be processed by the unit, and which can be rotated, about said axis and with respect to said receiving member in at least two different angular positions, each corresponding to locate one of said opening sections in front of said suction portion of said lateral wall of said receiving member so making operative only the holes facing the selected opening section.