Machine for forming filter bags for infusion products

Abstract

Described is a machine for making filter bags including: a rotary carousel having a plurality of grippers for retaining respective filtering chambers; each gripper is configured for moving the filtering chamber to a pick-up zone; a first reel of a first strip and a second reel of a second strip; a selector device including a first channel engaged by the first strip arriving from the first reel, and a second channel engaged by the second strip arriving from the second reel; the selector device has a shared outfeed at the pick-up zone; first and second movement means, positioned, respectively, along the first and the second channel for feeding, respectively, the first strip of tags and the second strip of tags, the first and second movement means are operated selectively in such a way as to feed alternately the first or the second strip.

1 . A machine for forming filter bags for infusion products, comprising:
 a carousel rotating in a stepwise fashion about an axis of rotation having a plurality of grippers arranged circumferentially and configured for retaining respective filtering chambers provided with a thread; each gripper being configured to move the filtering chamber to a pickup zone;   a first reel of a first strip and a second reel of a second strip; characterised in that it further comprises:   a selector device comprising a first channel engaged by the first strip arriving from the first reel, and a second channel engaged by the second strip arriving from the second reel; said selector device having a shared outfeed at the pickup zone;   first and second movement means, positioned, respectively, along the first and the second channel and configured for feeding, respectively, the first strip and the second strip, said first and second movement means being actuated selectively in such a way as to feed alternately:   the first strip, when the running out of the second strip is detected, or   the second strip, when the running out of the first strip is detected, in such a way as to guarantee continuity of operation;   a unit for cutting tags positioned close to said shared outfeed of the selector device and configured to cut a single tag at a time from the first strip, when the first strip is fed, or from the second strip, when the second strip is fed, in such a way that the single tag is associated with the thread of the filtering chamber carried to the pickup zone by the gripper;   a first and a second joining unit, respectively for the first and the second strip, positioned between the respective first and second reel and the respective first and second movement means, along a corresponding first and second path of the first and second strip; wherein each first joining unit is configured to join a final end of the first strip, when it is not fed by the first movement means, with an initial end of a new first strip coming from a new first reel, and each second joining unit is configured to join a final end of the second strip, when it is not fed by the second movement means, with an initial end of a new second strip coming from a new second reel; and   a dividing wall positioned in such a way as to separate the first and the second joining units from the carousel, said dividing wall being provided with a first and second slit to allow the passage, respectively, of the first and second strips, in such a way as to not interrupt said first and second paths.   
     
     
         2 . The machine according to  claim 1 , wherein said dividing wall also separates the first and the second joining units from the selector device 
     
     
         3 . The machine according to  claim 1 , wherein said dividing wall is part of a protective guard which encloses the carousel. 
     
     
         4 . The machine according to  claim 1 , wherein said dividing wall lies in a plane parallel with the axis of rotation of the carousel. 
     
     
         5 . The machine according to  claim 1 , wherein said first and second movement means are connected to a shared control unit configured to allow, selectively, a synchronised feeding with stepwise motion of the first strip to the tag cutting unit and at the same time keeping the second strip stationary, or keeping the first strip stationary and at the same time a synchronised feeding with stepwise motion of the second strip to the tag cutting unit. 
     
     
         6 . The machine according  claim 1 , wherein the selector device comprises a body having a wedge shape with vertex close to the tag cutting unit; said first and second channels being made, respectively, on two opposite surfaces of the body. 
     
     
         7 . The machine according to  claim 1 , wherein each of said first and second joining units comprises a respective supporting plate positioned, respectively, along the first and the second paths on which slide, respectively, the first and the second strips. 
     
     
         8 . The machine according to  claim 7 , wherein on each supporting plate there is at least one visual reference which can be aligned with visual references printed on the strips, in such a way as to allow a precise joint. 
     
     
         9 . The machine according to  claim 7 , wherein on each supporting plate there are articulated a first locking lever configured for locking on the supporting plate, in a predetermined position, the first or second strips which do not advance, and a second locking lever configured for locking on the supporting plate the new strip, in a predetermined position. 
     
     
         10 . The machine according to  claim 9 , wherein each supporting plate ( 19 ) comprises a grooved track positioned between the first and the second locking lever and configured to be engageable by a web cutting element. 
     
     
         11 . The machine according to  claim 10 , wherein the supporting plate is also equipped with a supporting lever configured to be positioned at the grooved track in such a way as to allow the web cutting element to slide along the grooved track remaining resting on the supporting lever. 
     
     
         12 . The machine according to  claim 1 , wherein the first and the second movement means each comprise a pair of opposite rollers and. 
     
     
         13 . The machine according to  claim 1 , wherein said first reel and second reel rotate on a respective axis of rotation parallel to the axis of rotation of the carousel. 
     
     
         14 . The machine according to  claim 1 , wherein said first and second reel said the carousel are positioned on vertical, coplanar and contiguous planes. 
     
     
         15 . A method for changing strips of tags during the formation of filter bags for infusion products comprising the steps of:
 preparing a carousel rotating in a stepwise fashion about an axis of rotation having a plurality of grippers arranged circumferentially and configured for retaining respective filtering chambers provided with a thread; each gripper moving the filtering chamber to a pickup zone;   preparing a first reel of a first strip;   preparing a second reel of a second strip;   stopping the feeding of the first strip when it is nearly finished, by first movement means; and synchronously   activating the feeding of the second strip by second movement means   cutting a single tag at a time from the first strip, when the first strip is fed, or from the second strip, when the second strip is fed, in such a way that the single tag is associated with the thread of the filtering chamber in the pickup zone, said cut being performed by a tag cutting unit positioned close to the pickup zone;   preparing a first and a second joining unit, respectively for the first and the second strip, positioned between the respective first and second reel and the respective first and second movement means, along a corresponding first and second path of the first and second strip; wherein each first joining unit is configured to join a final end of the first strip, when it is not fed by the first movement means, with an initial end of a new first strip coming from a new first reel, and each second joining unit is configured to join a final end of the second strip, when it is not fed by the second movement means, with an initial end of a new second strip coming from a new second reel;   preparing a dividing wall which separates the first and the second joining units from the carousel, said dividing wall being provided with a first and second slit to allow the passage, respectively, of the first and second strips, in such a way as to not interrupt said first and second paths.   
     
     
         16 . The method according to  claim 15 , wherein the step of stopping the first strip also comprises a step of moving away, that is, withdrawing, the first strip from the tag cutting unit. 
     
     
         17 . The method according to  claim 15 , wherein after stopping the first strip there are the following steps with the first reel of the first strip stationary:
 separating an end portion of the first strip from the first reel which is running out;   disassembling the first empty reel;   assembling a new first reel of a new first strip;   locking the end portion on a supporting plate using a first locking lever;   positioning an initial portion of the new first strip on the supporting plate superposed on the end portion, in such a way that indicator elements respectively of the end portion and on the initial portion correspond with a visual reference present on the supporting plate;   locking the initial portion on the supporting plate by means of a second locking lever;   cutting the end portion and the initial portion;   applying a joining web for joining the end portion and the initial portion;   freeing the end portion and the initial portion from the supporting plate releasing, respectively, the first and the second locking levers, in such a way that the new first strip can be fed to the tag cutting unit.