It is known to form tubular bags with a block bottom, where typically a web of flexible sealable wrapping material is formed into a tube provided with successive transverse seals around the bag contents, the tube being formed with side gussets adjacent the bottom seal and the material adjacent said seal folded over the base of the bag. Such bags may be produced on a vertical form fill and seal machine and would typically contain flowable material such as washing powder. It is also known to produce bags with a block top. Although the gussets required for forming a block top may be produced on a vertical form fill and seal machine, by insertion of gusset-forming fingers during the top sealing process in the same way as gussets may be formed for the bottom bag seal to produce a block bottom, the completion of a block top is conventionally carried out while the bags are stationary and after they have left the machine.

According to one aspect the invention provides bag handling apparatus including a plurality of bag holder means for receiving a bag from a bag making or filling machine, means for conveying successive holder means on an endless path extending substantially in a horizontal plane, at least one processing station, at which at least one sealing, cutting, gluing, folding or similar processing operation is carried out on successive bags conveyed to said station by said holder means, and means for delivering a processed bag from said holder means on said path.

Each holder means preferably has internal dimensions adapted to the size of the bag, so that it may adequately confine the bag and may also assist in maintaining or forming the shape of the bag, particularly during the processing stage or stages. In a preferred arrangement the holder means comprise open-topped containers so that bags may be received through the open top of the container, e.g. directly from a vertical form fill and seal machine. The containers may be adapted to allow completed bags to be delivered by said delivering means through

the bottom of the container. Thus, in a further preferred arrangement, the containers are in the form of sleeves, with open tops and open bottoms; in this arrangement the containers may conveniently be moved on said endless path by sliding over a stationary surface or on band conveyor means, with the delivering means operating at a gap in or between said surface and/or said band conveyor means.

The holder means may comprise individual unconnected members which are conveyed on said endless path by suitable conveying means, e.g. pushers, band conveyors or other means engaging the holder means. On portions of said path the holder means may move in line in abutment, with one holder means pushing the holder means in front of it. Alternatively, the holder means may be linked, e.g.

by forming pockets of a pocket conveyor. Thus, the holder means may be conveyed by endless conveyor means having means adapted to engage individual holder means and convey said holder means on said path in a predetermined relationship. The endless conveyor means may extend in a substantially horizontal plane adjacent said path. In all cases, the movement of the holder means may be synchronised with the machine from which bags are received.

There may be a series of processing stations on said endless path. Thus, typically the apparatus may be employed to produce block top bags from partially-completed bags received from a vertical form fill and seal machine. The processing station may comprise a sealing station at which the partially-completed bags are resealed with a permanent seal closer to the bag contents. At the sealing station the contents and/or material of the bag may be compressed and/or excess bag material removed (e.g. by cutting) after the new seal has been made. Downstream of the sealing station the holder means may convey the bags to a further processing station at which an adhesive strip (or adhesive tape or other means of securing) is applied to or adjacent the top sealed portion of the bag, and subsequently means may be provided at a further processing station for folding or pressing, e.g. by rolling, the top portion of each bag over so as to adhere the top material of the bag to form a block top bag. Preferably all the processes are carried out while the bag is conveyed on said path by said holder means.

The invention will be further described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a plan view of bag handling apparatus,

Figure 2 is a side view of the apparatus of Figure 1, Figure 3 is a schematic plan view showing stages of operation of the apparatus of Figure 1, Figures 4-6 are schematic perspective views showing process steps in the apparatus of Figure 1, Figure 7 is a schematic side view of the exit station of the apparatus of Figure 1, Figure 8 is a part-sectional side elevation of part of the sealing station of the apparatus of Figure 1, Figure 9 is a part-sectional plan view of the apparatus shown in Figure 8, Figure 10 is a part-sectional end elevation of the apparatus shown in Figure 8, Figure 11 is a part-sectional side elevation of part of a modified sealing station, Figure 12 is a part-sectional plan view of the apparatus shown in Figure 11, Figure 13 is a plan view of modified bag handling apparatus, Figure 14 is a sectional view on the line XIV-XIV in Figure 13, Figure 15 is a sectional view on the line XV-XV in Figure 13, Figure 16 is a sectional side view of a completed bag produced by the apparatus of Figure 13, and Figures 17A-17D are scrap sectional views showing operation of folding apparatus in the apparatus of Figure 13.

Referring to Figures 1 and 2, the bag handling apparatus 10 is linked to a vertical form fill and seal machine 12 which produces block bottom bags 14 having a gusseted gable top and typically formed from heat sealable plastics material and containing flowable material such as washing powder. The apparatus 10 receives the bags 14 from the machine 12 and conveys them on a path 16 on which the tops of the bags are trimmed and folded over so as to form a block top. The bags 14 are received and conveyed on the path 16 in pucks or holders 18 in the form of rectangular sleeves having open tops and open bottoms and adapted to the shape and size of the bag.

Referring also to Figures 3-7, empty holders 18 are supplied to a receiving station A, which is directly under the output position of the machine 12, so that successive bags 14 descend into a holder 18.

Movement of the holders 18 through the station A is synchronised with

output of the machine 12. The station A is located on a first straight run 16A of the path 16, which takes the form of a rectangular closed loop path. Holders 18 are moved along the path 16A by a first pusher 20 having a fixed stroke, the holders sliding over a stainless steel or similar surface 22. Thus, although not so shown in Figure 3, there would normally be a line of abutting holders 18 on the straight run 16A, the pusher 20 advancing each holder one pitch on each operation on receipt of an appropriate timing signal from the machine 12. The surface 22 is provided with holes 24 at and/or just downstream of the station A so that any loose powder or other filling material which may accompany the bags 14 when received from the machine 12 does not accumulate on the surface.

At the end of the run 1 6A successive full holders 18 are stopped in the path of a second pusher 26, which launches the holders along a second run 1 6B of the path 16. A sensor 28 detects when there is a holder in the path of the pusher 26. A similar sensor 30 is provided at the end of the run 16B. The pusher 26 will operate when the sensor 28 indicates that there is a holder 18 in its path and ready for pushing and if there is no holder 18 sensed by the corresponding downstream sensor 30. The pusher 20 and the other pushers provided on the path 16 operate in a similar manner, the pusher 20 being also synchronised with the machine 12 as described earlier.

An abutting line of holders 18 is advanced by the pusher 26 through a settling station B, which comprises a vibrating platform 32 over which the holders slide and which causes the product to settle in the bags 14.

At the end of the vibrating platform 32 each holder 18 is moved into a sealing station C in which the gable top of each bag is pressed down on the bag contents and the top of the bag resealed and excess packaging material above the new seal removed. As a result of compac- tion of the bag contents on the platform 32 and/or pressing on the bag in the sealing station as is explained in more detail with reference to Fig- ures 8-12 below, the new seal formed in the sealing station may be closer to the bag contents than the top seal made in the bag by the machine 12. In order to allow air to escape from the bag during this stage it is arranged that the top seal made in the machine 12 is only partial, e.g. by including gaps along the line of sealing where the seal is not made. As is described in more detail with reference to Figures 8-12

below, the sealing station C includes a carriage 34 including a pair of substantially horizontal parallel beams 36 provided on each side of the path 16B, the carriage being driven so that each of the beams performs a square motion in a vertical plane (see Figure 4). The carriage 34 also carries two sets of fingers 38, 40, movable with the beams 36.

Engagement of the fingers 38, 40 in slots 42 on each side of each holder 18 causes the holders to slide through the sealing station C on a further surface 33 forming part of the run 16B, this movement being achieved in two stages. Thus, during the downward portion of the square motion of the beams 36 the fingers 38 enter the slots 42 of a holder 18 which is stationary at the end of the platform 32. Subsequently , during horizontal forward movement of the beams 36, the fingers 38 move the holder 18 onto the surface 33 and into the sealing station C before the beams are raised, thus leaving the holder in the station. The horizontal distance between the sets of fingers 38 and 40 corresponds to the horizontal distance through which the beams 36 move, so that during the next downward movement of the beams the second set of fingers 40 engage in the slots 42 of the holder previously left in the station by the fingers 38. At the same time, during this downward movement the top gusset in the bag in the holder engaged by the fingers 40 is reformed and the contents compressed if necessary by plates 122 (Figures 9-12), as indicated at 37 in Figure 4. Also at this time the fingers 38 engage the next holder 18 at the end of the platform 32.

During horizontal movement of the carriage 34 through the station C the bag in the holder 1 8 engaged by the fingers 40 has its top resealed by sealing and cutting jaws 44, 46 which are carried by the beams 36 and which seal the top of the bag and cut off the excess 48 while the bag and holder are transported through the station C by the carriage. The jaws 44, 46 are brought together and retracted during the horizontal movement of the carriage 34 so that the sealing and cutting operation is completed just before the end of this movement, the final stage of which deposits the holder on the upstream end of a band conveyor 50 which carries the holder through a transport station D to the end of the run 16B. The excess material 48 is removed by an air blast from a jet 52, preferably before it falls onto the platform 33 or conveyor 50, and may additionally be directed to a waste collection receptacle by means of a suction duct 53.

The conveyor 50 delivers successive holders 18 into the path of a

pusher 54 which operates to slide an abutting line of holders 18 along a platform 56 forming a further run 1 6C of the path 16. On the run 1 6C the holder 18 passes through a gluing station Eat which a strip 58 of adhe- sive is applied along a sloping side of the top of the bag 14, as shown particularly in Figure 5. The adhesive may be applied by any convenient means at the station E, e.g. by roller or nozzle.

Beyond the gluing station E the holders 18 pass to the end of the platform 56 and into the path of another pusher 60, which operates to advance them along a platform 62 forming an initial part of a final return run 1 6D of the path 16. The pusher 60 cooperates with a sensor 64, similar to the sensors 28 and 30. During initial movement on the platform 62 each holder 18 passes through a rolling station F, at which the top flap of each bag 14 is rolled down by a weighted, pivoted flap roller 65 so that it is pressed onto the adhesive strip 58 and sealed down, thus forming a block top bag.

After the rolling station F the holders 18 are advanced by the pusher 60 to the eject station G, shown particularly in Figure 7. Holders 18 arriving at the eject station G are temporarily clamped in this position by side clamps 66, e.g. operated pneumatically. At the station G the platform 62 is formed with a hole 68 which allows the completed bag 14 to descend through the open bottom of the holder onto an exit platform 70. In order to ensure that bags do not remain in their holders 18 at the eject station G a vertical plunger 72 is moved downwards through each holder at the station. An exit pusher 74 operates to push a line of completed bags 14 along the exit platform 70 to an exit station H from which they may be removed. As shown in Figure 2, as an alternative to an exit platform 70, an exit band conveyor 71 may be used, in which case a pusher similar to the pusher 74 may not be required.

Downstream of the eject station G the empty holders 18 are deli- vered by the pusher 60 to the end of the platform 62, from which they are received on a continuously-moving conveyor 78 and returned to the beginning of the path 16, i.e. in position to be advanced towards the filling station A by the pusher 20. A sensor 80, similar to the sensors 28, 30 and 64, is provided adjacent to the pusher 20.

In the apparatus 10 holders 18 are transported around the path 16 by a combination of pushers and conveyors, as well as being transported through the sealing station C by the carriage 34. Note that in this case the orientation of the bags remains constant. By way of

explanation, it will be appreciated that the machine 12 produces a bag 14 with a longitudinal seal. In the illustrated apparatus this seal is typically located as indicated at 82 in the bag at station A in Figure 3.

Since the bag remains in the same orientation during its passage on the path 16 it is this side of the bag to which the adhesive strip 58 is applied at the gluing station E and which is folded over to form the block top.

The bags 14 could be transported in one or more pocketed conveyors instead of in individual holders. In this case, or in the case where the bags are transported in holders, the bags may be separately driven through the sealing station by means synchronised with the movement of the sealing jaws. In other words the sealing mechanism may not itself carry the bags through the station as it does in the illustra- ted embodiment.

Figures 8-10 show the sealing station C in more detail, and in particular the drive arrangement for the carriage 34. Thus, each of the horizontal beams 36 carries spaced outwardly-extending pins 100 each of which is connected to identical adjacent drive mechanisms 102 connected to a fixed part of the apparatus. Each mechanism 102 com- prises a planetary gear wheel 104 to which the pin 100 is rotatably atta- ched in a radially off-set position. The gear wheel 104 is rotatably mounted on one arm of a rotor 106 which has three equi-angularly spaced arms, the other arms carrying planetary gear wheels 108, 110.

The gear wheels 104,108,110 engage with a stationary internal annular gear 112. The rotors 106 are driven by a common timing belt 118 engaging pulleys 114 mounted on central spindles 116 of the rotors.

The main body of the carriage 34 is supported between the beams 36 and carries the sealing jaws 44, 46, which are operable by an air cylinder 120, as explained in more detail with reference to Figures 11 and 12.

The carriage 34 also carries on each side a former plate 122 positioned adjacent the second set of fingers 40 which engage in the slots 42 of the holders 18. Each plate 122 is movable by an air cylinder 124 from a retracted position, in which it is clear of the path of the holders 18 through the station C, and an extended position (as shown in Figures 9 and 10). The plates 122 are moved to their extended positions during the last part of the descent of the carriage 34 so as to extend into the gusseted top sides of the bag 14 in the holder 18 which is engaged by the fingers 40. Where necessary, the plates 122 reform the gussets

in the bag 14 and compress the bag contents just prior to and during sealing of the bag by the jaws 44, 46. The plates 122 remain in their extended positions during sealing but are retracted prior to upward movement of the carriage 34 following the sealing operation.

Figures 11 and 12 show a slightly modified sealing station C. In this, the fingers 38, 40 engage the rear faces of the holders 18 instead of in central slots. The holders 18 are formed at their sides with horizontal slots 126. As a holder 18 arrives at a position on the surface 33 from which it will be engaged by the fingers 38, pneumatically-operated pins 128 located on each side of the surface are fired so as enter the slots 126 and arrest the holder (if necessary) with the pins at the upstream ends of the slots (as shown in Figure 11): this prevents the holders overshooting the pick-up position. The pins 128 are retracted prior to horizontal movement of the holders following engagement of the fingers 38. Similar pins 130 are provided for the pick-up position for the fingers 40.

The jaws 44, 46 are movable together to perform the sealing and cutting operation under action of the pneumatic cylinder 120. The jaw 44 is connected to a movable assembly 45 comprising upper and lower mounting blocks 132,134 respectively slidable on upper and lower rails 136,138 welded onto upper and lower surfaces of longitudinal frame members of the carriage 34. The jaw 46 is similarly connected to a movable assembly 47 comprising upper and lower mounting blocks 140, 142 slidable respectively on upper rail 136 and a further lower rail 144 which is similar to and in alignment with the lower rail 138.

The jaw assembly 45 is directly connected to the piston of the air cylinder 120. A chain 146 is connected to the jaw assembly 45 on each side and passes around a sprocket 148 rotatably mounted on the carri- age 34. The opposite end of the chain 146 is connected to the jaw assembly 47. At each side of the assembly 47 a tension spring 150 is connected by way of a threaded block 152 at one end to the assembly 47 and by way of a further threaded block 154 at the other end to a fixed part of the carriage 34. Thus when the cylinder 120 advances the jaw 44 the chain 146 transmits a corresponding motion to the jaw 46, so that the jaws move together, the cylinder acting against the tension springs 150, which return the jaws to their retracted, open position when pressure in the cylinder is released. The jaws 44, 46 include sealing faces which seal the bag material by heat and/or pressure. Intermediate the jaw 44 is

a knife 156 which can be advanced relative to the jaw 44 by an air cylinder 158 and is operated at an appropriate time while the jaws 44, 46 are together, e.g. substantially at the end of the sealing operation. The knife 156 preferably operates against a slot or hardened insert in the jaw 46.

Figures 13-15 illustrate a modified bag handling apparatus 210 which performs similar functions to those performed by the previously-described apparatus. Parts having functions similar to those of corresponding parts in the apparatus of Figure 1 have been given reference numbers increased by 200.

Open-ended sleeve-like holders 218 are conveyed by an endless chain 219 around an endless path 216 on a substantially horizontal stainless steel platform 222. The chain 219 passes around four sprockets 221, at least one of which is driven intermittently to move the holders 218 on the path 216.

Each of the holders 218 has an integral extension arm 223 which removably connects the holder to the chain 219 by means of spaced apertures 225 in the arm through which extend adjacent upstanding pins 227 carried by successive links of the chain 219. The spacing of holders 218 on the chain 219 is such that every third pin 227 is not occupied.

Other spacings are possible, leaving no or more pins unoccupied, particularly for different sizes of bag 214 and holder 218. Thus, the holders 218 are replaceable with holders of different sizes so that the apparatus 210 is usable for various sizes of bag. It will be understood that holders 218 are regularly spaced around the chain 219 and that not all are shown in Figure 13.

Loading and other operations on the bags 214 are carried out in substantially similar ways and locations as in the apparatus of Figure 1, with differences as noted below.

The sealing station C in the apparatus of Figure 1 is replaced by sealing and trimming bars 244, 246, operable on the upper part of the bag and orientated to correspond with the orientation of the bag in the holder 21 8. The sealing and trimming bars 244, 246 operate on successive bags 214 (Figure 16) in successive holders 218 while the chain 219 is stationary.

The gluing station E and rolling station F are replaced by a folding station 290 and label applying station 292. As explained in more detail below with reference to Figures 16 and 17, the folding station 290

causes a double fold of the top sealed portion of the bag 214 and the label applying station 292 applies a label over the folded top sealed portion to retain it against the top of the bag so as to provide a block-top formation.

As shown in Figure 16, the completed block-top bag 214, as is produced by the apparatus of Figures 13-15, includes a folded top-seal portion 213 held in position by a resealable label 215. Prior to entry to the folding station 290 the top-seal portion 213 is upstanding, as shown in Figure 17A. At the station 290 the portion 213 enters a substantially vertical channel arranged between spaced guides 251 A and 251 B.

Subsequently, as the bag 214 is moved through the folding station 290, that part of the portion 213 extending above the guides 251A and 251B is engaged by a folder bar 251 C and folded over as shown in Figure 1 7B. The orientation of the folder bar 251 C progressively changes (i.e.

twists) along the length of the folding station 290 so that the engaged part of the top-sealed portion 213 assumes the configuration shown in Figure 1 7C. Subsequently, downstream of the guides 251 A and 251 B, a presser bar 251 D engages over the top-sealed portion 213 and progressively presses it onto the top surface of the bag 214. The bar 251 D retains the portion 213 in this position until the label 215 is applied by a label applying device in the station 292.

Downstream of the station 292 the bag 214 is complete and is delivered through an aperture 268 in the platform 222 for subsequent conveyance to downstream processing or packaging apparatus (not shown). A plunger (not shown), similar to the plunger 72 in the apparatus of Figure 1, may operate vertically downwards to ensure removal of a completed bag 214 from each successive holder 218 as it hesitates over the aperture 268.

Apparatus similar to that of Figures 13-15 could be used to produce bags which differ in form from that of the bag 214 (including the type of bag 14 produced by the apparatus of Figure 1).