AU727118B2 - A machine for automatically forming, filling, and closing bags having transverse closure ribs - Google Patents

Description

-1- P/00/0011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventor: Address for service in Australia: Invention Title:

FLEXICO-FRANCE

Henri BOIS CARTER SMITH BEADLE 2 Railway Parade Camberwell Victoria 3124 Australia A MACHINE FOR AUTOMATICALLY FORMING, FILLING, AND CLOSING BAGS HAVING TRANSVERSE CLOSURE RIBS The following statement is a full description of this invention, including the best method of performing it known to us 1 A MACHINE FOR AUTOMATICALLY FORMING, FILLING, AND CLOSING BAGS HAVING TRANSVERSE CLOSURE

RIBS

The present invention relates to the field of bags or sachets that include complementary closure ribs adapted to enable the user to open and close them successively at will.

More precisely, the present invention relates to the field of machines for the purpose of making such bags, in particular machines adapted automatically to form, fill, and close packages based on film, in particular film made of thermoplastic material, and including complementary closure ribs, e.g. complementary male and female closure ribs.

Such machines are often referred to as "Form, Fill, 15 and Seal machines" or by the abbreviation FFS machines.

Numerous machines of this type have already been proposed (see for example documents EP-A-528721 and US-A-4 894 975).

Most such machines have a former which is fed with 20 the film in the plane state taken from pay-out means and which delivers the film shaped into a tube; a filler chute opening out into the former and consequently into said tube; means for conveying closure ribs and fixing them to the film; longitudinal heat-sealing means for closing the tube longitudinally; and means suitable for sequentially generating a first transverse line of sealing before a product is placed in the tube via the filler chute, and then a second transverse line of sealing after the product had been placed in the tube, thereby closing the package around the product.

Still more precisely, most machines that have been proposed in the past are designed to receive closure ribs in the longitudinal direction, i.e. parallel to the travel direction of the film. However, such longitudinal-rib machines suffer from the drawback of limiting the height of the resulting bags. The height is equal to half the circumference of the former. Also, packages obtained from such machines are sometimes not entirely leakproof. This can be the result in particular from the fact that the transverse heat-sealing means are prevented from operating properly by the extra thickness as constituted by the longitudinal ribs.

Numerous attempts have been made to seek to improve this situation, by placing the closure ribs not longitudinally, i.e. parallel to the travel direction of the film, but transversely, i.e. perpendicular to the travel direction of the film.

The earliest attempt on these lines and known to the inventors is described in documents US-A-4 617 683 and US-A-4 655 862. Those documents are about 10 years old and they propose two solutions for conveying the ribs transversely onto the film while it is in the plane state, i.e. before the film reaches the former. The first solution consists in displacing lengths of closure rib laterally by means of drive wheels placed laterally beside the moving film, in combination with a 20 transversely displaceable suction head. The second Ssolution consists in placing the closure ribs on the film by means of a rotary barrel provided with pneumaticallycontrolled temporary holding means.

Those attempts were promising, to begin with. However, in the end they did not give satisfaction and they have been abandoned by the person skilled in the art. In particular, it has been observed that the means described in the above-mentioned documents are not suitable for ensuring that the ribs are always placed in accurately rectilinear manner on the film. Consequently, it is often difficult to make the complementary ribs cooperate.

Other solutions have therefore been proposed in attempts to overcome the drawbacks that result from the means described in the above-mentioned documents.

By way of example, document US-A-4 666 536 proposes winding a portion of the film on a mandrel and conveying a length of closure rib onto said wound portion of film, said length extending across the width of the film and being conveyed via a heating tunnel that serves to fix the ribs. The means described in that document theoretically present the advantage of allowing shaping to be performed continuously. Nevertheless they turn out to be very complex and difficult to implement.

In order to form a film that is provided sequentially with complementary closure ribs, document US-A-4 701 361 proposes extruding a tubular film provided with helical closure ribs that may be extruded or that may be added on, and then cutting the tubular film helically so as to obtain a strip provided with uniformly distributed transverse ribs.

15 To reduce the length of rib deposited on the film, and consequently improve the positioning of the ribs, document US-A-4 878 987 proposes feeding the ribs not by means of a lateral feed as described in documents US-A-4 617 683 and US-A-4 655 862, but from two rib feeds 0 disposed on respective sides of the film that is to form the bags. Thus, each of the two lengths of rib move over the film from a respective one of the two side supplies extends no longer over the entire width of the film, but "0 only after half of the width thereof.

Subsequently, document US-A-4 844 759 has proposed two other solutions. The first such solution consists in driving the closure ribs by means of an endless belt over a bracket that overlies the film and that pivots through 1800, so as to overturn the closure ribs onto said film. In this way, the ribs are initially conveyed along the bracket with their relief directed towards the film, after which they are turned over so that the relief faces away from the film for the purpose of being fixed onto the film. The second solution consists in conveying the ribs transversely on a shoe that overlies the film and then in lowering the shoe against the film so as to fix the closure ribs in place.

After observing that none of the techniques described in the above-mentioned documents gives satisfaction, document US-A-5 111 643 proposes acting in a completely different way which consists not in fixing the closure ribs on the film prior to bringing the film to the former as described in the above-specified documents, but in initially forming the film into the form of a tube, on the former tube, and then in placing the closure ribs on the tubular film. To this end, document US-A-5 111ii 643 proposes a complex installation that includes a chute opening out at the base of the former for the purpose of conveying the closure ribs as carried by a support strip, together with a chute for "removing the support strip.

15 A beto h 15 An object of the present invention is to improve machines for shaping film-based packages that include complementary closure ribs.

*4 According to the present invention, this object is achieved by a machine characterized in that it includes 20 means for conveying closure ribs transversely relative to the film and comprising in combination: a rectilinear guide superposed relative to the *film and extending transversely relative thereto, the ~guide being designed to positionaccurately at least one closure rib transversely over the film; and means for grasping the leading end of the closure rib and capable of moving transversely along the guide to convey the closure rib therealong by pulling on the leading end of the closure rib.

The invention is preferably applied to automatic machines for forming, filling, and closing film-based packages of conventional type and comprising a former that is fed with the film in the plane state coming from pay-out means and that delivers the film shaped into a tube; a filler chute that opens out into the former and consequently into said tube; means for conveying closure ribs transversely relative to the film before the film reaches the former and for fixing the ribs to the film; longitudinal heat-sealing means for closing the tube longitudinally; and means suitable for sequentially generating a first transverse line of sealing before a product is put into the tube via the filler chute, and then a second transverse line of sealing when the product has been put into the tube, so as to close packaging around the product.

Thus, the present invention goes against the prejudice associated with the means described in the first documents US-A-4 617 683 and US-A-4 655 862.

Whereas numerous designers have held the opinion that the means described in those documents were incapable of giving satisfaction, thereby giving rise to the numerous 15 subsequent proposals recalled above, the present inventors, after numerous experiments, have found that a solution based on the means described in those documents US-A-4 617 683 and US-A-A 655 862 can indeed give satisfaction, providing they include an improvement 20 consisting in combining a rectilinear guide with grasping means that operate by pulling the closure ribs.

In another advantageous characteristic of the .invention, the means for conveying the closure ribs are ooe adapted to fix to the film one of two mutually engaged complementary ribs each of length that is approximately equal to half the width of the film, and means are also provided suitable for fixing the second closure rib to the inside wall'of the film once shaped into a bag, after the bag has been filled, and while the bag is being finished.

To facilitate these operations of fixing closure ribs in two stages, it is preferable for the two closure ribs to be carried by support strips of different widths.

Other characteristics, objects, and advantages of the present invention appear on reading the following detailed description with reference to the accompanying drawings given by way of non-limiting example, and in which: Figure 1 is a diagrammatic perspective view of a machine of the invention for automatically forming, filling, and closing bags; Figures 2 and 3 are diagrams showing two variant implementations of the invention; Figure 4 is a vertical section view of the machine on plane referenced II-II in Figure 1; 1 0 Figure 5 is a side view of a bag of the invention; and Figure 6 is a perspective view of a bag of the invention that has gussets.

Accompanying Figure 1 shows the conventional general 15 structure of a machine for automatically forming, filling, and closing bags that include complementary closure ribs, the machine comprising: means 10 for feeding film F; a former a filler chute longitudinal heat-sealing means 40; and transverse heat-sealing means 50 that also serve to separate bags.

Since this general structure is known, it is not described in detail below.

However, as mentioned above, according to the invention, in order to convey the closure ribs P properly transversely over the film F prior to the film reaching the former 20, provision is made for: a rectilinear guide 100 overlying the film

F,

extending transversely to the travel direction thereof, and located upstream from the former 20; the guide 100 is designed to position at least one closure rib P accurately transversely above the film F; and eans 150 for grasping the leading end of the closure rib P; which grasping means 150 is suitable for moving transversely along the guide 100 so as to move the closure rib P therealong by pulling on the leading end of the closure rib.

The rectilinear guide 1 00 can be implemented in various different ways.

In a first embodiment, the guide 100 is constituted by a rigid rectilinear channel of section that is complementary to at least a portion of the closure ribs p.

In a second embodiment, the rectilinear guide 100 is constituted by a channel formed by two pivoting jaws, which in the closed position receive the rib P moved by the means 150, but which are capable of opening so as to facilitate subsequent placing of ribs p on underlying films F.

The g r a s ping means 150 can also The grasping means 150 can also be implemented in :various different ways.

As shown diagrammatically in accompanying Figure 1 the grasping means are preferably formed by a clamp system controlled to close in order to grasp the leading end of a rib so as to move it along the rectilinear guide 100, and then to open so as to release the rib p before returning to the initial grasping position as shown diagrammatically in Figure 1.

In a variant embodiment, the grasping means 150 may be constituted by a suction head.

:.at Naturally, provision is preferably made for means that displace the grasping means 150 transversely and in synchronism with displacement of the film

F.

Auxiliary means are preferably provided for conveying the ribs P: drive wheels 200 and 202; a guide 204 for the ribs upstream from the film F; means 206 for cutting the ribs p into lengths (the ribs p being Preferably fed from a supply in the form of a reel 208); and a position sensor 210.

The closure ribs p are fixed to the film F by any appropriate means, advantageously using heat-sealing jaws 8 associated with the rectilinear guide 100, as represented by reference 120 in Figure 1.

The ribs p can be put into place on the film F in various different ways.

In a first variant, the system is adapted to place the closure ribs P so as to cover the entire width of the film F, said ribs P being fixed to the film F along their full length, as represented in Figure 3, and coming into engagement solely after the tubular film has been folded over and compressed after the bag has been filled, while the bag is being finished.

However, in another variant, as represented in Figure 2, the system can be adapted to place directly on the film F a pair of mutually-engaged ribs p that cover 15 only half of the width of the film F, one of the two ribs, P1, being adjacent to the film and being fixed thereto in the station for positioning the ribs by means of the heat-sealing jaws 120, while the superposed second .rib P2 is fixed to the inside of the bag while the bag is being finished after it has been filled. Under such circumstances, the second rib P2 can be heat-sealed to the film F by means of the heat-sealing jaws 50 or by means of additional transverse heat-sealing jaws 52, as shown diagrammatically in Figure 4.

In the context of this second solution, and as shown in Figure 4, it is preferable for the support strip 54 of the second rib P2 to be wider than the support strip 56 of the first rib P1 so as to make the second heat-sealing operation easier.

With the rib P extending transversely across the film F before the film reaches the former 20, it is preferable to provide means that make it easier to pass through the former To this end, it is possible either to place the former 20 off-center relative to the vertical axis of the machine so as to allow the transverse closure ribs P to 9 pass, or else to leave sufficient clearance in the former Also, the resulting bags can themselves be of numerous different kinds, and special mention may be made of the following: Sas shown in Figure 5, is it possible to make precut lines 80 between the closure ribs P and the second transverse line of sealing 82 (which precut line can be made in conventional manner by means of toothed knife blades associated with the transverse heat-sealing jaws "sloping-shoulder" or "coat-hanger" type curved longitudinal lines of sealing can be made, as shown at 84 in Figure 5, in particular for applications that package 15 a liquid; such lines of sealing 84 are generally rounded in shape, being convex towards the inside of the bag and converging towards the top thereof which coincides with .r the second transverse line of sealing 82; in Figure 5, 86 designates the first transverse line of sealing and 88 the longitudinal line of sealing made using jaws 40 for the purpose of interconnecting the longitudinal edges of the film F; the "coat-hanger" lines of sealing 84 are preferably symmetrical about a midplane of the bag extending transversely relative to the lines 82 and 86 and they are made by means of heat-sealing jaws of complementary shapes; and bags can be made that have lateral gussets 90 and 92, as shown in'Figure 6, by forming longitudinal folds in the film F before it penetrates into the former In Figure 4, reference 51 designates a cutting tool associated with the transverse heat-sealing jaws 50 for the purpose of separating finished bags, and reference 53 designates a cutting tool suitable for being used to make the precut line The closure ribs P can themselves be implemented in numerous different ways.

As shown in Figure 2, they can be constituted by complementary asymmetrical male and female ribs P1 and P2.

As shown in Figure 3, they may equally well be constituted by ribs P of constant section and suitable for mutual engagement after being folded over.

Means are preferably provided, e.g. in the form of two-material ribs P or equivalent means, enabling a melting temperature to be defined for the outside surfaces of the support strips 54 and 56 that is lower than the melting temperature of the inside surfaces thereof.

The film F used may also be implemented in numerous ways. It may be constituted by a flexible film of 15 plastics material comprising one or more layers, and optionally coated, where appropriate, in a metal layer.

~The present invention provides numerous advantages over systems that exist in the prior art, and particular mention may be of the following: 20 by putting the closure ribs P into place under traction, and by doing so on a guide 100, it is possible to position them very accurately across the width of the film F and to do so in the rectilinear state; the invention is very easy to implement; and the resulting bag is leakproof (since the closure ribs extend parallel to the transverse heat-sealing means they do not interfere with the operation thereof).

Naturally, the present invention is not limited to the particular embodiments described above, but it extends to any variant coming within the spirit of the invention.

Thus, as described above, the invention is applicable to machines for automatically forming, filling, and closing film-based packages.

However, the invention can also be applied to machines for preparing films that are fitted with ribs, which rib-fitted films are subsequently fed to conventional machines for automatically forming, filling, and closing packages.

In the description above, the grasping means are constituted either by a clamp system or by a suction head. In another variant, the grasping means may be constituted by a needle carried by drive means adapted firstly to move the needle with reciprocating motion, either in translation or by pivoting, towards and away from the guide 100 so as to engage the rib P when in the position close to the guide, and to move the needle back and forth along the guide 100. More precisely, the drive means are adapted firstly to move the needle towards the feed end of the guide 100 to engage the free end of the rib P coming from the supply 208, secondly to move the 15 need along the guide 100 while keeping the needle engaged with the rib so as to move the rib by applying traction to its leading end, thirdly to move the needle away from the guide 100 so as to release the rib P at the end of its feed stroke, and fourthly to return the needle back 20 along the guide 100 towards the feed end thereof while keeping the needle away from the rib, prior to repeating the drive cycle starting from the first-mentioned step above, but with the following length of rib P.

a

Claims (2)

1. 22. Packaging obtained by using a machine according to any one of claims 1 to 21.
2. 23. A machine substantially as hereinbefore described with reference to the accompanying drawings. DATED: 23 August 2000 Freehills Carter Smith Beadle Patent Attorneys for the Applicant: FLEXICO-FRANCE RNM:DL:#40251850 23 August 2000