Method of and apparatus for increasing the permeability of wrappers of rod-shaped articles

Abstract

Apparatus for increasing the preferabilities of central portions of tubular wrappers which form part of successive filter cigarettes of double unit length being turned out by a tipping machine. The central portions of the wrappers include adhesive-coated uniting bands which are convoluted around filter mouthpieces in a first portion of a rolling channel for successive filter cigarettes. A perforating unit which employs laser beams is set up to simultaneously perforate the central portions of the wrappers of several successive cigarettes in a second portion which immediately follows or partially overlaps the first portion of the channel. Each wrapper can be provided with two or more annular arrays of perforations.

What is claimed is:  
     
         1 . A method of changing the permeabilities of tubular wrappers of rod-shaped products of the tobacco processing industry, comprising the step of simultaneously changing the permeabilities of wrappers of a plurality of products.  
     
     
         2 . The method of  claim 1 , wherein said step includes perforating the wrappers of n≧2 products, n being a natural number.  
     
     
         3 . The method of  claim 2 , wherein said perforating step includes establishing a source of n at least substantially parallel laser beams, and directing the n beams upon n−x oscillatable beam reflecting mirrors to focus the n beams upon the wrapper of at least one product, x being a natural number less than n.  
     
     
         4 . The method of  claim 3 , wherein n equals two.  
     
     
         5 . The method of  claim 3 , further comprising the step of moving the products in the course of said changing step and oscillating each mirror to thus focus the beams upon the wrappers of moving products.  
     
     
         6 . The method of  claim 5 , wherein n equals two.  
     
     
         7 . The method of  claim 2 , wherein said changing step includes simultaneously perforating m selected portions of the wrapper of each product.  
     
     
         8 . The method of  claim 7 , wherein m≧2 and is a natural number.  
     
     
         9 . The method of  claim 8 , wherein said perforating step includes directing m substantially parallel pulsating laser beams upon the wrapper of each product.  
     
     
         10 . The method of  claim 9 , wherein said perforating step includes simultaneously directing p laser beams upon q partially reflecting mirrors to reflect a first portion and to permit passage of a second portion of each laser beam, and directing the second portions of the laser beams against at least one fully reflecting mirror, m being equal to p (q+1) wherein p is a natural number and q is a natural number including zero.  
     
     
         11 . A device for changing the permeabilities of tubular wrappers of a series of at least substantially equidistant rod-shaped products, comprising: 
 means for emitting n laser beams; and    means for simultaneously directing the laser beams upon the wrappers of n products, n being a natural number greater than one and said directing means including n−x movable mirrors arranged to deflect a plurality of beams making an acute angle the magnitude of which is a function of the distance between neighboring products of said series, x being a natural number less than n.    
     
     
         12 . The device of  claim 11 , further comprising means for moving the products of the series along a predetermined path and means for oscillating each mirror to thus focus the beams upon the wrappers of selected products in said path.  
     
     
         13 . The device of  claim 12 , wherein said directing means includes means for simultaneously focussing at least one discrete beam upon each of m different portions of the wrapper of each of the series of products in said path, m being a natural number exceeding one.  
     
     
         14 . The device of  claim 13 , wherein said oscillating means includes means for oscillating the n−x mirrors about a common axis.  
     
     
         15 . The device of  claim 11 , wherein said mirrors include q=(m/p)−1 partially transmitting mirrors arranged to split each of p incident beams into a reflected first portion and a transmitted second portion, and at least one fully reflecting mirror for said second portions of the beams, p being a natural number and q being a natural number including zero.  
     
     
         16 . Apparatus for treating smokers' products of the type wherein a rod-shaped component is surrounded by a tubular wrapper carrying a deformable strip, comprising: 
 a rolling unit having a plurality of surfaces defining a channel and including at least one first surface which moves relative to at least one second surface, said channel having an inlet and an outlet;    means for feeding into said inlet successive products of a series of products having tubular wrappers each of which is contacted by the respective strip whereby the wrappers are caused to roll due to contact with said surfaces and to thus convolute the respective strips thereabout in said channel; and    means for changing the permeabilities of the wrappers during rolling in a predetermined portion of said channel, comprising means for simultaneously perforating the wrappers of at least two products in said predetermined portion of said channel.    
     
     
         17 . The apparatus of  claim 16 , wherein said channel includes an additional portion which is disposed at said inlet and the strips are convoluted around the respective wrappers in said additional portion of said channel, said predetermined portion of said channel immediately following said additional portion, as seen in a direction from said inlet toward said outlet, said perforating means being arranged to change the permeabilities of the wrappers of products at least in said predetermined portion of said channel.  
     
     
         18 . The apparatus of  claim 17 , wherein said perforating means is constructed and arranged to start the perforating of wrappers in said additional portion of said channel.  
     
     
         19 . The apparatus of  claim 16 , wherein at least a portion of said channel has an arcuate shape.  
     
     
         20 . The apparatus of  claim 16 , wherein said rolling unit comprises a rotary conveyor having a cylindrical peripheral surface constituting said at least one first surface, and a stationary rolling member having a concave surface concentric with and spaced apart from said peripheral surface and constituting said at least one second surface.