Packaging machinery

Abstract

A vertical form, fill and seal (VFFS) packaging machine comprising a pair of sealing jaws ( 12; 100; 200,202; 302,304 ) mounted directly or indirectly on parallel shafts ( 10; 102; 206,208; 300 ) for rotation in opposite directions on opposite sides of the path of the packaging material ( 36; 118; 204; 308 ) so that the jaws engage the packaging material simultaneously on opposite sides to form successive horizontal seals, and stripping means comprising, in association with the sealing jaw on each side of the path of the packaging material, a pair of stripper carriers ( 22; 54; 66; 116; 222,224,226,228; 314 ) mounted for rotation around the corresponding shaft at or near the respective ends thereof, or about an axis parallel to the shaft, a horizontal stripper bar ( 18 B; 40 A; 50 A; 62; 110; 234; 310 ) mounted at its respective ends on the two stripper carriers and arranged to be movable with respect to the stripper carriers so that the stripper bar can engage the packaging film along a predetermined vertical stripping path along which, in cooperation with a similar stripper bar associated with the sealing jaw on the other side of the packaging material, it acts to displace downwards any product which might otherwise be trapped in the area of the seal, the stripper carriers being arranged to be rotated faster than the shafts at least while the stripper bars are performing each stripping operation.

1 . A packaging machine of the type described, for forming downwardly moving packaging material into bags containing product, comprising a pair of sealing jaws ( 12 ;  100 ;  200 , 202 ;  302 , 304 ) mounted directly or indirectly on parallel shafts ( 10 ;  102 ;  206 , 208 ;  300 ) for rotation in opposite directions on opposite sides of the path of the packaging material ( 36 ;  118 ;  204 ;  308 ) so that the jaws engage the packaging material simultaneously on opposite sides to form successive horizontal seals, and stripping means comprising, in association with the sealing jaw on each side of the path of the packaging material, a pair of stripper carriers ( 22 ;  54 ;  66 ;  116 ;  222 , 224 , 226 , 228 ;  314 ) mounted for rotation around the corresponding shaft at or near the respective ends thereof, or about an axis parallel to the shaft, a horizontal stripper bar ( 18 B;  40 A;  50 A;  62 ;  110 ;  234 ;  310 ) mounted at its respective ends on the two stripper carriers and arranged to be movable with respect to the stripper carriers so that the stripper bar can engage the packaging film along a predetermined vertical stripping path along which, in cooperation with a similar stripper bar associated with the sealing jaw on the other side of the packaging material, it acts to displace downwards any product which might otherwise be trapped in the area of the seal, the stripper carriers being arranged to be rotated faster than the shafts at least while the stripper bars are performing each stripping operation.  
     
     
         2 . A machine according to  claim 1 , in which the movable mounting of each stripper bar on its respective carriers causes or enables the stripper bar to move outwards from its axis of rotation and thus, owing to its greater speed, to overtake the corresponding sealing jar as it approaches the packaging material in preparation for performing a stripping operation.  
     
     
         3 . A machine according to  claim 2 , in which each sealing jaw carries behind it a movably mounted clamping member ( 42 ;  68 ;  104 ;  254 ) arranged, in cooperation with an opposed clamping member on the other side of the packaging material, to prevent product from falling past it and into the area which is about to be sealed or has just been sealed by the cooperating opposed sealing jaws, and in which each stripper bar is arranged by virtue of its speed and position to pass the corresponding clamping member and to engage the packaging material to commence a stripping operation before the clamping member reaches the packaging material, thereby stripping also the area about to be engaged by the clamping member.  
     
     
         4 . A machine according to any one of  claims 1  to  3 , in which each shaft carries two sealing jaws 180 degrees apart from one another, and the stripper carriers on each side of the packaging material carry just one stripper bar and are driven at a speed or average speed twice that of the shafts.  
     
     
         5 . A machine according to any one of  claims 1  to  4 , in which the shafts are driven by a servo motor and the stripper carriers are driven by a separate servo motor.  
     
     
         6 . A machine according to  claim 5 , in which the servo motor driving the stripper carriers is controllable as to its speed and/or phase, whereby the stripping operation with respect to its speed and/or timing can be adjusted while the machine is running.  
     
     
         7 . A machine according to any one of  claims 1  to  6 , in which each stripper bar is mounted at its ends on arms which are pivotally or slidably mounted on the corresponding stripper carriers.  
     
     
         8 . A packaging machine of the type described, comprising a pair of cooperating sealing devices ( 100 ;  200 , 202 ;  302 , 304 ) mounted directly or indirectly on parallel shafts ( 10 ;  102 ;  206 , 208 ;  300 ) for rotation in opposite directions on opposite sides of the path of the packaging material ( 36 ;  118 ;  204 ;  308 ) so that the sealing devices engage the packaging material simultaneously on opposite sides to form successive horizontal seals, each sealing device comprising two oppositely disposed sealing jaws ( 100 A,  100 B for example) whereby two seals are formed during each revolution of the shafts; and stripping means comprising a pair of cooperating stripper bars ( 40 A;  50 A;  62 ;  110 :  234 ;  310 ) for engaging opposite sides of the packaging material, each stripper bar being carried at its ends by arms which are pivotally or otherwise movably mounted on rotary stripper carrying members ( 22 ;  54 ;  66 ;  116 ;  222 ;  314 ) lying beyond the ends of the sealing jaws and being driven at an average or set speed twice that of the shaft, whereby the stripping means strips downwards any product lying within the packaging material, in each region about to be sealed, in advance of each pair of sealing jaws engaging the packaging material, the pivotal or other movement of the arms being such as to allow the stripper bars to move past the sealing jaws in order to perform the stripping operations.  
     
     
         9 . A machine according to  claim 8 , in which each sealing jaw carries behind it a movably mounted clamping member ( 42 ;  68 ;  104 ;  254 ) arranged to engage the packaging material above the sealing jaw, the corresponding stripper bar being arranged to overtake the clamping member before performing each stripping operation.  
     
     
         10 . A packaging machine of the type described, comprising one or more of sealing devices ( 12 ;  100 ;  200 , 202 ) arranged to engage opposite sides of the packaging material ( 36 ;  118 ;  204 ) to produce transverse seals at regular intervals, each sealing device being continuously driven for movement along a closed path; and a pair of stripping devices arranged to engage opposite sides of the packaging material to strip downwards any product contained within the packaging material in the area about to be sealed by the sealing devices; each stripping device comprising a stripper bar ( 18 B;  40 A;  50 A;  62 ;  110 ;  234 ) carried at its ends by arms ( 40 ;  50 ;  64 ;  112 ;  232 ) which are movably mounted on stripper carriers ( 22 ;  54 ;  66 ;  116 ;  222 , 224 , 226 , 228 ) located to the sides and separately from the corresponding sealing device, whereby movement of the arms relative to the stripper carriers causes or allows each bar to move away from the axis of rotation so as to clear and thus be able to move past the corresponding sealing device so as to perform a stripping operation in advance of engagement of the sealing device with the packaging material, the stripper carriers being driven at a rotational speed such as to cause the stripper to have a speed greater than the sealing device at least while passing the sealing device and performing a stripping operation.  
     
     
         11 . A packaging machine of the type described, comprising two cooperating sealing devices each comprising at least one sealing jaw ( 100 A,  100 B for example) driven by a shaft (for example  102 ) so as to move continuously along a closed path, and each sealing device having an associated stripping means comprising at least one stripper bar (for example  110 ) pivotally or otherwise movably mounted at its ends on two rotating carrier members ( 116 ) arranged to be driven continuously at a speed which is greater than that of the shaft at least while performing each stripping operation, the movable mounting of the stripper bar on the corresponding carrier members allowing or causing the stripper bar to move along a closed path extending around the path of the sealing jaw or jaws and having a straight portion extending along the packaging material to perform successive stripping operations in cooperation with a similarly movable stripper bar on the other side of the packaging material.  
     
     
         12 . A machine according to  claim 11 , in which each sealing device comprises two oppositely disposed sealing jaws ( 100 A and  100 B for example) and in which the stripping means associated with each sealing means comprises a single stripper bar ( 110 ) which is driven by the carrier members ( 116 ) at a set or average speed twice that of the shaft ( 102 ) of the associated sealing means.  
     
     
         13 . A machine according to  claim 12 , including means ( 238 ) for resiliently urging the stripper bar away from the axis of rotation of the corresponding carrier members, whereby the stripper bar lies at a large enough radius to be able to overtake each sealing jaw in preparation for performing a stripping operation.  
     
     
         14 . A machine according to  claim 13 , including means ( 120 ) for guiding the stripper bar away from the packaging material after the completion of each stripping operation.  
     
     
         15 . A machine according to any one of  claims 11  to  14 , in which the carrier members ( 116 ) for each stripper bar ( 110 ) are mounted on end portions of the shaft of the corresponding sealing device for rotation relative to the shaft.