GB2139174A - Filling of flexible packages - Google Patents

Abstract

A packaging tube is formed around a vertical former and from thence led, by a vertically reciprocable device 72, upwardly towards a hopper 74 from which material is delivered to the package. The device comprises a pair of hollow, resiliently deformable jaws 10 which can be moved between open and closed positions and from a flat configuration in which they can grip and/or close the mouth of the tube to an arcuate configuration in which they open the mouth of the tube for filling, suction being applied to hollow interior of the jaws to hold the tube thereagainst. In a modification (Fig. 7), the device is not vertically reciprocable and the tube is fed upwardly to it by a pair of endless conveyors. <IMAGE>

Description

SPECIFICATION Filling of flexible packages This invention relates to filling of flexible packages and more particularly, but not exclusively, the formation of a flexible package followed by filling and closure of the package.

Devices are already known for forming a pouch or package, filling the pouch and subsequently sealing it. Such devices comprise a vertical, circular hollow forming tube. Packaging material is led from a reel downwardly around the forming tube. The packaging is vertically sealed to form a tube. The tube of material is closed at the bottom by horizontal sealing jaws and is drawn downwardly to the required length. Product is dropped under gravity down the inside of the forming tube. The material tube is then sealed at the top and severed from the remainder of the material.

This conventional vertical form, fill and seal machine has a number of disadvantages, the most serious of which are: The product has to fall under gravity through the length of the forming tube and in so doing changes in flight from a closely arranged "portion" to being spread out. Depending on the nature of the product the spreading during fall through the forming tube will vary but in any event the speed of the machine is governed by the speed with which all the product arrives in the pouch. Until all the product is received the pouch cannot be sealed and the next pouch formed. The length of the forming tube is, therefore, the determining factor but the tube length is itself fixed since the tube provides a support for the formation of the vertical seal.

Another major disadvantage is that conventional machines require horizontal sealing jaws and cutting means to reciprocate through a distance equal to the pouch length. Thus a considerable weight of machinery is caused to move and it is difficult to control the accuracy of such movements at high speeds. Without such accuracy sealing of the material tube and separation of the formed and filled pouches may be applied at the wrong places.

The present invention has been made from a consideration of these problems.

According to the invention there is provided a device for filling flexible packages comprising deformable jaws, means for moving the jaws between a first closed position and an open position, means for changing the shape of the jaws, suction means for holding flexible packing material in contact with the jaws when the jaws are in the open position.

In a preferred embodiment of the invention the device is combined with a pouch or package forming apparatus which comprises a forming means over which flexible package forming material is led generally upwardly. The package mouth is adapted to be presented to the jaws which close thereon. The jaws then move to a circular position to permit product to be received in the package. If desired means may be provided for transporting the jaws from a position where they receive the package mouth to a position where they present the package to receive product therein.

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:. Figure lisa diagrammatic plan view of the jaw assembly; Figure 2 is a transverse section through a jaw of Figure 1; Figure 3 is a view in side elevation of a bag forming, filling and sealing device incorporating the jaw assembly of Figure 1; Figures 4, 5 and 6 show the device of Figure 3 at different stages in the cycle of operations thereof; and Figure 7 is a side elevation of another embodiment of a bag forming, filling and sealing device.

Referring to Figures 1 and 2 of the drawing the jaw assembly comprises a pair of deformable jaws 10, 12. Each jaw comprises a flexible tubular body 14 which may be of rubber plastics such as polyviny Ichloride and which is supported buy a backing 16 of spring steel or like material. The tubular body has an aperture 18 on the side thereof directed away from the backing. The aperture 18 may be continuous or may be in the form of slots, holes or the like at intervals along the tubular body.

Each jaw 10, 12, is fixed at substantially the mid point of the support 16 thereof to a bar 20, 22 respectively. Bar 20 is fixed to a hollow piston rod 24 which extends through cylinder 26 in which piston 28 on the rod 24 can reciprocate. A similar arrangement of hollow piston rod 30, cylinder 32 and piston 34 is associated with bar 22. Each hollow piston rod is connected to the interior of its associated tubular body.

A fixed cross bar 36 extends in parallel spacedapart relationship to bar 20. Pivot arms 38,40 are pivotably mounted one at each end of the cross bar 36. The other end of each pivot arm is pivotably connected to one end of the jaw 10. A similar arrangement of cross bar 42, and pivot arms 44 and 46 is provided for jaw 12.

The jaw assembly operates as follows: When the pistons 28 and 34 are moved towards each other into the positions marked 28a and 34a, bars 20 and 22 are also moved towards each other.

The jaws are thereby also moved towards each other but because each jaw is linked at its end by the pivot arms to a fixed cross bar, the jaw ends can only move laterally. The net effect, therefore, is for each jaw to move from a semi-circular configuration to the straight line position (shown in dotted lines), the pivot arms having moved to the positions marked 38a, 40a, 44a and 46a. When the pistons are returned to the starting position the jaws open and revert two the semi-circular configuration. Both jaw assemblies also move in towards each other and back away from each other by use of a piston (not shown).

By virtue of the connection of the hollow piston rods 24 and 30 to the tubular bodies 14 the air pressure within the tubular bodies can be reduced.

Now if the top of a flexible bag, for example of plastics, is introduced between the jaws, whilst the jaws are away from each other upon closing of the jaws the bag is flattened out and held between the jaws. Then with suction applied to the flat tubular bodies the bag mouth is held on the jaws when the jaws are re-aligned to their substantially circular disposition. With the bag held in this way it can readily be filled with a product. When the product has been received in the bag the jaws are re-aligned again to the flattened out position amd the bag can be closed or sealed. Finally the jaws are withdrawn away from each other with suction applied to only one of the tubular bodies, to allow removal of the filled and closed bag.

The jaw assembly can be used with preformed bags but is advantageously combined with a bag forming device as will now be described with reference to Figure 3.

Packaging material 60 in strip form is led from a reel (not shown) to a vertically disposed tubular former 62 which is preferably of circular crosssection but may have oval or other section. The material is led upwardly over the former so that the strip wraps around the former with the edges over-lapping. A vertical seal is formed by a reciprocating vertical sealing means 64. After leaving the formerthe material, now in the form of a tube, is led through the nip of a pair of forwarding rollers 66, A movable cutter 68 and movable sealing device 70 are located above the rollers 66. Ajaw assembly 72, such as described with reference to Figures 1 and 2 is mounted (or means not shown such as a carriage) for movement between the position shown in Figure 3 and a raised position just below a hopper 74. A second movable sealing device 76 is provided below the hopper.

When the material has been advanced to the position shown in Figure 3 between the open jaws of jaw assembly 72, the jaws of the jaw assembly are closed and the material thereby held. The jaw assembly is then raised to its upper position below the hopper and the jaws re-aligned with suction applied so that the mouth of the tube is opened also (Figure 4). It will be appreciated that as the jaw assembly lifts the material tube to the hopper fresh material is drawn over the former 62 using the driven rollers 66. The vertical seal is formed by sealing means 64 when the material is stationary.

The sealing device 70 is operated to close the tube at that point and form a bag. A measured amount of product is then allowed to fall from the hopper into the bag so formed.

After filling, the jaws of the jaw assembly are re-aligned to the flattened out position, the upper seal is formed by the sealing device 76 and at the same time the cutter 68 severs the package 80 from the remainder of the material (Figure 5).

One jaw of the jaw assembly having suction applied thereto is withdrawn which pulls the package 80 to one side whereupon on release of the suction it falls under gravity down a chute 82 (Figure 6). The jaw assembly then moves to its lower position ready to receive material as shown in Figure 3 which is advanced upwardly by the required amount and the cycle of operations is repeated.

If the packaging material does not feed sufficiently evenly for the jaws of the jaw assembly to grip the material precisely the apparatus just described can be modified so that the cutter 68 and sealing device 70 move to allow the jaw assembly closer to the nip of rollers 66 to receive the material. Alternatively in place of such additional movement of the jaw assemblythe rollers 66 may be made to make a small upward movement to presentthe material to the jaws of the jaw assembly.

Registration of the packaging material to ensure precise package length can be effected in a conventional manner using an "eye" marker on the packaging material which registers on a photo-cell adapted to control the amount of material advanced by rollers 66.

If the packaging material is sufficiently rigid or self-sustaining it is possible to modify the apparatus so that the jaw assembly remains in its upper position below the hopper and the packaging material is advanced to the jaw assembly by the rollers 66. In the embodiment shdwn in Figure 7 the jaw assembly is, as just mentioned arranged to remain in the upper position. Two endless conveyors 84,86 are arranged to receive, between their adjacent nips, packaging material from the rollers 66 and transport the material to the jaws of the jaw assembly. When the requisite length of packaging material has been advanced the endless conveyors are withdrawn to the positions shown in dotted lines so that the bag can be filled.

It is to be understood that the invention is not limited to the above described embodiment; many modifications can be made. For example the lower sealing device 70 can be located below the rollers 66 to produce a bottom seal at an appropriate moment prior to filling. In such an arrangement only the cutter 68 is disposed above the rollers 66 so that, in the embodiment where the jaw assembly traverses between upper and lower positions, the jaw assembly can be brought nearer the rollers 36 to receive packaging material.

Although the described embodiments are of a substantially vertically aligned apparatus, a part of the apparatus can be horizontal or inclined to the vertical. For example the forming tube 62 can be disposed horizontally and the packaging material in tubular form led from the horizontal tube around a roller into a vertical alignment to the nip of rollers 66.

With the present invention very high speeds of bag filling can be obtained, for example of the order of 120 bags per minute. This compares favourably with conventional apparatus which will fill at the rate of 60-80 bags per minute.

Claims (11)

1. Adeviceforforming and/orfilling packages comprising deformable jaws, means for moving the jaws between a first closed position and an open position, means for changing the shape of the jaws and suction means for holding packing material in contact with the jaws when the jaws are in the openposition.

2. A device as claimed in Claim 1,wherein at least one jaw comprises a hollow body having apertures therein by which packing material can be attached to the jaw by suction.

3. A device as claimed in Claim 1 or Claim 2 wherein each end of each jaw is linked to a fixed point so that application of force to the jaw intermediate the ends thereof causes the jaw to change shape.

4. A device as claimed in any preceding claim, wherein jaws substantially define a circle in their open position.

5. A device as claimed in any preceding claim, and comprising forming means over which package forming material can be drawn by the jaws or by conveyor means.

6. A device as claimed in Claim 5, wherein means are provided for moving the jaws relative to the forming means.

7. A device as claimed in any preceding claim, wherein means are provided for delivering product to a package held by the jaws, when said jaws are in the open position.

8. A device as claimed in Claim 7, wherein means are provided for sealing the bottom of the package prior to product being delivered therein.

9. A device as claimed in any preceding claim, and comprising means for sealing the top of a package when the jaws are in the closed position.

10. A device as claimed in any preceding claim wherein means are provided for discharging a filled package from the jaws.

11. Adeviceforforming and/orfilling packages substantially as described herein with reference to Figures 1 to 6 or Figures 1 to 6 as modified by Figure 7 of the accompanying drawings.