A rotating cam device for a pick-up head provided with pick-up members arranged side by side and at a variable distance;
- the device extending along a horizontal axis and comprising a first cam and at least a second cam, which extend around said horizontal axis, are suitable to be engaged by tappet elements carried respectively by a first and a second pick-up member, and have, at least partially, a sloped or spiral shape for causing a translation of said tappet elements parallel to said horizontal axis in response to a rotation of said first and second cams about said horizontal axis;
- wherein second cam is axially movable in respect to said first cam at least when said device is installed in said pick-up head.