Cardboard Filter For Cigarettes, Cigarette And Manufacturing Method Thereof

Abstract

The invention relates to a cardboard filter for cigarettes, formed by folding, winding and gluing a cardboard strip. According to the invention, the cardboard strip is folded to form a central portion having a series of lobes angularly equally distributed around a central axis of the filter and a peripheral portion surrounding the central portion, the lobes and the peripheral portion delimiting gas passage channels around the central axis.

1 . A method for manufacturing a cardboard filter for cigarettes, formed by folding, winding and gluing a cardboard strip,
 wherein the cardboard strip is folded to form a central portion having a series of lobes angularly equally distributed around a central axis of the cardboard filter and a peripheral portion surrounding the central portion,   the lobes and the peripheral portion delimiting gas passage channels around the central axis,   the cardboard filter in which the lobes delimit therebetween a central space containing the central axis,   wherein the method comprises a step of immobilizing the cardboard filter, in which the cardboard filter is threaded by a machine through its central space around a pin to hold the cardboard filter, then a step of fixing a sheet delimiting an axial tube intended to contain tobacco, in which the sheet is glued by the machine in the continuation of the peripheral portion on an axial end of the peripheral portion of the cardboard filter held on the pin, then a step of separating the cardboard filter from the pin.   
     
     
         2 . The method of  claim 1 , wherein the gas passage channels are angularly equally distributed around the central axis of the cardboard filter. 
     
     
         3 . The method of  claim 1 , wherein the lobes have at least one outer portion being in contact against the peripheral portion. 
     
     
         4 . The method of  claim 1 , wherein at least one of the lobes comprises:
 at least one outer segment, which is located facing the peripheral portion,   a first inner segment, which extends between a first outer end fold of the outer segment and a central area of the cardboard filter comprising the central axis,   a second inner segment, which extends between a second outer end fold of the outer segment and the central area of the cardboard filter.   
     
     
         5 . The method of  claim 4 , comprising at least one first lobe and one second lobe, which is adjacent to the first lobe,
 the second inner segment of the first lobe being linked to the first inner segment of the second lobe by an inner end fold of them.   
     
     
         6 . The method of  claim 1 , wherein one of the lobes comprises:
 at least one outer segment located facing the peripheral portion,   a first inner segment that is not folded relative to the outer segment,   a second inner segment which extends between a second outer end fold of the outer segment and the central area of the cardboard filter,   another area of the peripheral portion, located facing the outer segment, being connected to the first inner segment by a first outer fold.   
     
     
         7 . The method of  claim 1 , wherein the peripheral portion is of a frustoconical shape around the central axis. 
     
     
         8 . The method of  claim 1 , wherein the peripheral portion is of circular cylindrical shape around the central axis. 
     
     
         9 . The method of  claim 1 , wherein the lobes delimit therebetween a central space containing the central axis. 
     
     
         10 . The method of  claim 1 , having at least three lobes. 
     
     
         11 . The method of  claim 1 , having five lobes. 
     
     
         12 . The method of  claim 1 , wherein a sheet delimiting an axial tube intended to contain tobacco is glued on an axial end of the peripheral portion in the continuation of the peripheral portion.