Method and a device for the assembly of packets for tobacco products

Abstract

Cigarette packets are assembled by a method that involves dabbing or spraying a cold-setting adhesive onto selected areas of a blank fed along the wrapping line of a packaging machine, whereupon the blank is folded to form a packet; should there be a break in operation of the machine following the application of the adhesive, persisting for a certain length of time, the method includes a heat-reactivation step whereby the adhesive applied previously to the blank is warmed to a given temperature so as to restore its bonding properties and guarantee the ultimate stability of the assembled packet.

1 . A method of assembling packets for tobacco products directed along a wrapping line ( 1 ) of a packaging machine equipped with feed means supplying a wrapping material ( 3 ) from which the packets ( 2 ) are made, including the step of applying a layer or dab of cold-setting adhesive ( 8 ) to predetermined areas ( 8   a ,  8   b ) of the wrapping material ( 3 ), and the step of folding the wrapping material ( 3 ) to form a packet, characterized in that it further includes at least one step of reactivating the cold-setting adhesive ( 8 ) applied to the predetermined areas ( 8   a ,  8   b ), by exposing the selfsame areas to heat, at a predetermined reactivation temperature (t r ).  
   
   
       2 . A method as in  claim 2 , including a cooling step following the heat-reactivation step.  
   
   
       3 . A method as in  claim 1 , wherein the heat-reactivation step is implemented on all packets ( 2 ) assembled by the packaging machine.  
   
   
       4 . A method as in  claim 1 , wherein the heat-reactivation step is initiated following a break in operation of the packaging machine lasting for a predetermined interval of time (T 1 -T 2 ).  
   
   
       5 . A method as in  claim 1  including a step, following the folding step, of restraining the packets ( 2 ), wherein the step of reactivating the cold-setting adhesive ( 8 ) by exposure to heat occurs concurrently, at least in part, with the restraining step.  
   
   
       6 . A method as in  claim 1 , wherein the heat-reactivation step is implemented by means of heated restraint elements.  
   
   
       7 . A method as in  claim 1 , wherein the heat-reactivation step precedes the folding step.  
   
   
       8 . A method as in  claim 1 , wherein the heat-reactivation step occurs during the course of the folding step.  
   
   
       9 . A method as in  claim 7 , wherein the heat-reactivation step is implemented by radiating heat on the predetermined areas ( 8   a ,  8   b ) to which the cold-setting adhesive ( 8 ) has been applied.  
   
   
       10 . A method as in  claim 1 , wherein the heat-reactivation step occurs as the wrapping material ( 3 ) advances along the wrapping line ( 1 ).  
   
   
       11 . A method as in  claim 1 , further including the steps of measuring the length of time (T) elapsing during a break in operation of the packaging machine, and comparing the resulting stoppage time (T) with the predetermined interval of time (T 1 -T 2 ) between a first predetermined critical time value (T 1 ) and a second predetermined critical time value (T 2 ), within which any degradation of the cold-setting adhesive ( 8 ) and consequent loss of bonding properties can be reversed by implementing the heat-reactivation step.  
   
   
       12 . A device for the assembly of packets for tobacco products, comprising feed means by which a wrapping material ( 3 ) is advanced along a wrapping line ( 1 ) of a packaging machine, means ( 4 ) by which to apply a layer or a dab of cold-setting adhesive ( 8 ) to predetermined areas ( 8   a ,  8   b ) of the wrapping material ( 3 ), and folding means by which the wrapping material ( 3 ) is formed into a packet, characterized in that it further comprises heater means ( 15 ) serving to reactivate the cold-setting adhesive ( 8 ) applied to the predetermined areas ( 8   a ,  8   b ), by exposure of the selfsame areas to heat, at a predetermined reactivation temperature (t r ).  
   
   
       13 . A device as in  claim 12 , comprising cooling means ( 28 ) located downstream of the heater means ( 15 ) along the feed direction followed by the wrapping material ( 3 ) and serving to cool at least the predetermined areas ( 8   a ,  8   b ) exposed previously to the action of the heater means ( 15 ).  
   
   
       14 . A device as in  claim 12 , wherein the action of the heater means ( 15 ) is applied to all of the packets ( 2 ) assembled by the packaging machine when in operation.  
   
   
       15 . A device as in  claim 12 , comprising processing means ( 16 ) able to measure a stoppage time (T) resulting from a break in operation of the packaging machine and connected on the output side to a control unit ( 17 ) such as will generate a signal to activate the heater means ( 15 ) in the event that the stoppage time (T) resulting from the break in operation of the packaging machine is within a given interval of time between a first predetermined critical time value (T 1 ) and a second predetermined critical time value (T 2 ), within which any degradation of the cold-setting adhesive ( 8 ) and consequent loss of bonding properties can be reversed by implementing the heat-reactivation step.  
   
   
       16 . A device as in  claim 12 , further comprising means ( 14 ) by which to restrain the packets ( 2 ), positioned downstream of the folding means ( 5 ), wherein the cold-setting adhesive ( 8 ) is heat-reactivated by means ( 15 ) associated with the restraint means ( 14 ).  
   
   
       17 . A device as in  claim 16 , wherein the restraint means ( 14 ) comprise an outfeed channel ( 9 ) delimited by the active branches ( 13 ) of two conveyor belts ( 10 ) offered in contact to the flank faces of the packets ( 2 ), and the cold-setting adhesive ( 8 ) is heat-reactivated by means ( 15 ) comprising heated plates ( 18 ) breasted with the reverse faces of the active branches ( 13 ).  
   
   
       18 . A device as in  claim 12 , wherein the cold-setting adhesive ( 8 ) is heat-reactivated by means ( 15 ) positioned upstream of the folding means ( 5 ).  
   
   
       19 . A device as in  claim 18 , wherein the cold-setting adhesive ( 8 ) is heat-reactivated by means ( 15 ) comprising at least one convector heater or at least one radiator.  
   
   
       20 . A cigarette packer, comprising a device as in  claim 12.