Method and a machine for making filter cigarettes

Abstract

Cigarettes are manufactured on a machine that includes a filter tip attachment comprising a train of rollers with peripheral suction grooves, each proportioned to hold a single cigarette. The grooves are set parallel to the axis of rotation of the relative rollers and combine to establish a feed path along which the cigarettes are attracted and released, passing from one roller to the next and advancing through a succession of processing stations. To optimize the attraction and release steps, the cigarettes themselves are exploited in such a way as to create a chamber in each groove, compassed between the cylindrical surface of the cigarette and the bottom surface of the groove it occupies, and connected to the pneumatic circuits generating the suction.

What is claimed:  
     
         1 ) a method of making filter cigarettes in a machine comprising a plurality of rollers each furnished peripherally with a plurality of suction grooves accommodating respective cigarettes and aligned on axes parallel to the axis of rotation of the relative roller, in such a manner as to establish a feed path along which the cigarettes are successively retained, released and transferred from a groove of one roller to a groove of a successive roller, including a step of creating at least one negatively pressurized chamber within each groove of at least one of the rollers, compassed between the bottom surface of the groove and a cigarette occupying the selfsame groove.  
     
     
         2 ) A method as in  claim 1 , wherein the chamber is created by causing the cigarette to engage in contact with the relative groove along at least one longitudinal area presented by the bottom surface of the groove.  
     
     
         3 ) A method as in  claim 2 , wherein the chamber is located at least on one side of the longitudinal area.  
     
     
         4 ) A method as in  claim 2 , wherein the chamber is divided by the area of contact into two half-chambers.  
     
     
         5 ) A method as in  claim 1 , wherein the chamber is created by causing the cigarette to engage in contact with the relative groove along at least two longitudinal areas of the mutually opposed flank faces presented by the groove, in such a way that the chamber is compassed between a portion of the cylindrical surface of the cigarette delimited by the two areas of contact, and the portion of the surface of the groove delimited by the selfsame areas of contact.  
     
     
         6 ) A method as in  claim 1 , wherein the chamber is divided into two negatively pressurized half-chambers.  
     
     
         7 ) A method as in  claim 6 , wherein the half-chambers are created by causing the cigarette to engage in contact with the relative groove not only along the two longitudinal areas of the mutually opposed flank faces presented by the groove, but also along an intermediate rib presented by the bottom surface of the groove.  
     
     
         8 ) A method as in  claim 1 , wherein at least one negatively pressurized chamber is created in each of the grooves of at least two contiguous rollers, compassed between the bottom surface of the groove and a cigarette occupying the selfsame groove.  
     
     
         9 ) A method as in  claim 8 , comprising a step whereby the cigarettes are transferred from releasing grooves presented by a first of the two contiguous rollers to receiving grooves presented by the second roller, during which the cigarette remains in contact simultaneously, as the rollers rotate through a predetermined angular distance, with at least two longitudinal areas of the mutually opposed flank faces of the releasing groove and with at least two longitudinal areas of the mutually opposed flank faces of the receiving groove.  
     
     
         10 ) A method as in  claim 8  where dependent on  claim 4 , comprising a step whereby the cigarettes are transferred from releasing grooves presented by a first of the two contiguous rollers to receiving grooves presented by the second roller, during which the single cigarette remains in contact simultaneously, as the rollers rotate through a predetermined angular distance, with three longitudinal areas of the releasing groove and with three longitudinal areas of the receiving groove.  
     
     
         11 ) A method as in claims  8 ,  9  and  10 , wherein the transfer step is effected as the rollers rotate about their respective axes through an angular distance substantially of six degrees.  
     
     
         12 ) A machine for making filter cigarettes, comprising a plurality of rollers each furnished peripherally with a plurality of suction grooves accommodating respective cigarettes and aligned on axes parallel to the axis of rotation of the relative roller, in such a manner as to establish a feed path along which the cigarettes are successively retained, released and transferred from a groove of one roller to a groove of a successive roller, wherein each groove of at least one roller comprises a bottom surface merging with two mutually opposed flank faces and positioned so as to engage in contact along a longitudinal area with a relative cigarette occupying the groove, thereby creating at least one chamber delimited on one side by the longitudinal area of contact and connected to a source of negative pressure.  
     
     
         13 ) A machine for making filter cigarettes, comprising a plurality of rollers each furnished peripherally with a plurality of suction grooves accommodating respective cigarettes and aligned on axes parallel to the axis of rotation of the relative roller, in such a manner as to establish a feed path along which the cigarettes are successively retained, released and transferred from a groove of one roller to a groove of a successive roller, wherein each groove of at least one roller comprises a bottom surface merging with two mutually opposed flank faces positioned to engage in contact along at least two longitudinal areas with a relative cigarette occupying the groove, thereby creating at least one chamber compassed between the bottom surface of the groove and the portion of the cylindrical surface of the cigarette directed toward the bottom surface of the groove, and connected to a source of negative pressure.  
     
     
         14 ) A machine as in  claim 13 , wherein the chamber is divided into two half-chambers connected to a source of negative pressure.  
     
     
         15 ) A machine as in  claim 14 , wherein the division between the two half-chambers is created by a longitudinal rib extending along the bottom surface of the groove and affording a relative area offered in contact to the cigarette.  
     
     
         16 ) A machine as in  claim 13 , wherein each groove of at least two contiguous rollers comprises a bottom surface merging with two mutually opposed flank faces positioned to enter into contact along at least two longitudinal areas with a relative cigarette occupying the groove, thereby creating at least one chamber compassed between the bottom surface of the groove and the portion of the cylindrical surface of the cigarette directed toward the bottom surface of the groove, and connected to a source of negative pressure.  
     
     
         17 ) A machine as in  claim 16 , configured in such a manner that when cigarettes are transferred from the releasing grooves of a first of the two contiguous rollers to the receiving grooves of a second roller, a first flank face of the releasing groove and a first flank face of the receiving groove and a second flank face of the releasing groove and a second flank face of the receiving groove are separated respectively by a distance marginally less than the diameter of a single cigarette, with the result that the cigarette remains in contact simultaneously, as the rollers rotate through a predetermined angular distance, with two longitudinal areas of the flank faces of the releasing groove and with two longitudinal areas of the flank faces of the receiving groove.  
     
     
         18 ) A machine as in  claim 15  or in  claim 16 , wherein the longitudinal ribs of the releasing groove and the receiving groove are separated, during the rotation of the two contiguous rollers through the predetermined angular distance, by a distance marginally less than the diameter of a single cigarette, with the result that the cigarette remains in contact simultaneously with three longitudinal areas of the releasing groove and with three longitudinal areas of the receiving groove.  
     
     
         19 ) A machine as in  claims 12  to  18 , wherein each groove is furnished with at least one hole connected to the source of negative pressure.  
     
     
         20 ) A machine as in  claims 12  to  18 , wherein each groove is furnished with at least two holes located at points near to the opposite ends of the selfsame groove and connected to the source of negative pressure.  
     
     
         21 ) A machine as in  claims 12  to  20 , wherein each groove is fashioned with portions, located to coincide at least with the two ends, contoured in such a way as to engage substantially in flush contact with a relative cigarette over the full area extending between the two longitudinal areas of contact.  
     
     
         22 ) A machine as in  claim 12 , wherein the chamber consists in two longitudinal channels afforded by the bottom surface of the groove and combining with the area of contact to create two half-chambers.  
     
     
         23 ) A machine as in  claim 22 , wherein the groove is furnished with at least one hole positioned to coincide with the area of contact, connected to the source of negative pressure and presenting a countersunk mouth allowing communication with both of the half-chambers.