The invention relates to a distributing device for cut tobacco, to be used in cigarette making machines, which includes a pointed rotating drum which takes or receives the cut tobacco, and a pointed detaching roller which cooperates with said drum and detaches the cut tobacco from same.
The pointed drum can take the cut tobacco from a bulky mass of tobacco contained in a box. In this case the pointed drum cooperates also with a pointed equalizer drum, rotating and preferably with a shorter diamater, and which removes the excess of tobacco taken by the drum, leaving, attached to the points of the latter, only a thin layer of cut tobacco, constant in thickness, and which is then removed from the drum by the action of the detaching cylinder.
The pointed drum can, however, receive the cut tobacco, already previously spread and carded which is fed from the top into a vertical duct, wherein a column of tobacco is formed. This tobacco is taken by the pointed drum, in the form of a uniform and thin veil, at the basis of the said vertical duct, and it is then removed from the drum by the detaching roller.
In the cut tobacco distributing devices of the known previous art, the rotating detaching roller is also provided with points and, therefore, it exerts a mechanical action on the tobacco, which damages the tobacco itself and determines a substantial degradation of same.
The invention has the purpose of eliminating this inconvenience and of ensuring a much more delicate treatment of the cut tobacco.
This purpose is achieved by the invention through the fact that the points of the drum are retractable inside the drum itself and are controlled by means which retract the same temporarily in a complete or almost complete manner in the region of the detaching cylinder, which is constructed as a smooth (without points) pneumatic suction cylinder. In this way the cut tobacco kept in the points of the drum is released by the complete and temporary retraction of such points in the region of the detaching cylinder which removes the tobacco from the drum by simple suction, without any sensible resistance and practically with no mechanical damage. Subsequently the points of the drum are caused to protrude again, to take or receive again a layer, or veil, of cut tobacco.
According to one embodiment of the invention the means which control the travel of the retractable points in the drum are adjustable in such a way as to make it possible to vary the degree of projection of the points from the body of the drum, in order to vary the quantity of cut tobacco taken or received in the time unit, by the pointed drum itself.