Device to automatically cut the slubbing of a yarn being worked

A device to automatically cut the slubbing, or spinning sliver, (11) of a yarn being worked, the device being used in any textile machine whatsoever and comprising a cutting assembly (17) and sensor means (18) functionally associated with the cutting assembly, the sensor means (18) being suitable to detect the presence or absence of the yarn (11a) downstream of a draft and to activate the cutting assembly (17) at least when they do not detect the presence of the yarn (11a), the cutting assembly (17) comprising a support with which a blade is associated, the blade being moveable with respect to the support to selectively assume an inactive position of non-interference with the slubbing (11) passing through or a cutting position in which it abuts against a contrasting element to cut the slubbing (11) transversely, the device being characterised in that the cutting assembly (17) comprises an electromagnet (21) and in that a magnetic element (35) is suitable to cooperate with the moveable blade (26) to keep it constrained to the core (21a) of the electromagnet (21) to assume the inactive position (26a), the electromagnet (21a) being able to be temporarily activated to generate a magnetic field suitable to take the blade (26) to the cutting position (26b), against the action of the magnetic element (35), the blade (26) and the electromagnet (21) being associated with an actuator assembly (20) the position of which can be regulated with respect to the support (19), the blade (26) in its inactive position (26a) is substantially vertical and in its cutting position (26b) abuts against the contrasting element (29) with a defined angle of incidence (α), the contrasting element (29) and the actuator assembly (20) can be selectively associated on the right or on the left of the support (19).