AU767438B2 - Method and apparatus for opening and transporting bags - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 DIVISIONAL APPLICATION NAME OF APPLICANT(S): CRYOVAC, INC.

ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street Melbourne, 3000.

INVENTION TITLE: "METHOD AND APPARATUS FOR OPENING AND TRANSPORTING BAGS" .0000 0 0 0 00 The following statement is a full description of this invention, including the best method of performing it known to us: METHOD AND APPARATUS FOR OPENING AND TRANSPORTING SAGS Field Of The Inveion The present invention relates to a method ahd apparatus for opening a bag mounted on a tape, and a method and apparatus for transporting the bag to a loading mechanism, where the product can be loaded into the bag.

BactkroundOf The Invention Many packaging applications, especially food packaging, require or bmenfit from the use of bags made from various thermoplastic materials and structues. Examples of commercial bags include heat shrinkable bags supplied by Cryovac, Inc., including the 8110, and B2550 bags.

These bags are commouly used in large scale meat processing and/or packaging syst where production speed and efficiency are important Bags to be used in these systems are often S. 15 themselves packed in boxes, the individual bags taped together so that they will feed in a predicti* able and efficient manner to an article loading staiion. Typical of such technology is US Patnt No. 3,161,347 (Hannon), disclosing a tape to which bags are attached, and US Paent No. 3, 587, 843 (Wing), incorporated herein by reference in its entirety, disclosing two tapes to which are attached imbricated shingled) bags.

At the loading station of a convtional system, each bag is opened and then loaded with an article such as a fresh red meat subprimal or smoked and processed meat poultry, cheese, or 0000 other perishable food product, or other product.

In opening such bags, a problem sometimes eacunter d is that of bag lips the edges of the bag panels which form the bag mouth or opening) which can be undesirably stuck together, or stuck to the adhesive bag tapes. This ocurs in conjunction with the use of adhesive tapes to hold a series of imbricated (shingled) bags. Lateral movanet of the top ply of the lead bag o relative to the bottom ply can cause the top ply of the bag to adhere to the adhesive tape, making it difficult to open the bag. This can create a significa slow-down in a packaging line, and down-time for the food processor or other user of bags. The bags can of course be opened manually, but this is very slow and labor intensive. It also risks unnecessary handling of the bag.

Some solutions have been offered to deal with the problem of opening a bag prior to the insrtian of an article into the bag. The use of air pressure is cammon, but of course requires a saurce of air pressure. Sometimes the use of air pressure is unpredictable in providing consistnt bag opening performance, and the operator sorcimes still needs to manually star the opening 2 proccas so that the air can be Effcctive in further opening the bag sufficiently to allow an article to be loaded therein.

Another problem inherent in conventional bag loading systems is the requircn to match ceter to center tape spacing to the bag size and article cross section. "Tape spacing" here refers to the pair of adhesive carrier tapes, e.g. as described in the '843 Wing patent, which in many commercial bag loading systems hold bags together in an imbricated anner before loading with an article. Currently, the nantre of the tape spacing will'gcnerally define the shape of the bag when it is opened. Since the bag dimensions are ideally matchedto the dimensions of the article to be packaged, tape spacing is an important parameter in loading a bag with an article.

It is desirable to provide a method and apparatus which lessen or eliminate the requirement of opening the bag manually, or of using air pressure. It is also desirable to provide a method of opening the bag in a reliable and consistent manner, which allows for increased automnation, and potentially reduces operating costs.

15 Likewise, it is desirable to provide a method and apparatus which lesson or climinate the requiremet of matching tape spacing to articl size, ie. the requirement of optimizing tape spacing for feeding or indeidng the bags, Another problem often encountered in the packaging of food products is that the comers Sof each big tend to curl over during bag advance and loaing. This can sometims complicate or slow ft bag loading procss; By finding a way to widen the tape spacin, that is, by placing the tapes closer to the bag's respective lateral edges, without being unduly limited in the need to match tape spacing to bag and article size, this problemn is lessened or eliminated.

In transporting bags mounted an a tape, in conventional systems, a discharged package (iLe. a product such as a frsh red meat packaged in a bag) is required to travel over the bag train, i.e. a plurality of imbricated bags mountd on tapes. A disadvantage of such a system is that bags can be knocked offthe bag train by the packaged product as it is transported.

9• Another problem common in conventional systems is that the packaging machine takes up a significant amount of floor space. In processing plants, where floor space is at a premium, this can be a impoant factor.

It is desirable to provide a method and apparams which reduces or eliminates the problem of bags being knocked offthe bag train by packaged products, and which reduces the overall floor length of the machine. preferably without sacricing th abity to horiantally load.

P:\OPERA.xd2452116.res.doc-04O9A)3 -3- Summary of the Invention In a first aspect, a method of opening a bag mounted on a tape comprises providing a bag comprising a first panel, a second panel, a first bag edge, a second bag edge, a bag bottom, and a bag mouth; providing a first means for vacuumizing and a second means for vacuumizing; drawing a vacuum through said first means for vacuumizing and a second means for vacuumizing; gripping the bag between the first means for vacuumizing and the second means for vacuumizing; and moving the first and second means for vacuumizing such that the bag disengages from the tape, and the bag mouth opens.

In a second aspect, a method of opening a bag mounted on a tape comprises providing a bag comprising a first panel, a second panel, a first bag edge, a second bag edge, a bag bottom, and a bag mouth; gripping the bag between a first means for vacuumizing and a second means for vacuumizing; drawing a vacuum through the first means for vacuumizing and the second means for vacuumizing; and moving the first and second means for vacuumizing such that the bag disengages from the tape, and the bag mouth opens.

In a third aspect, a method of opening a bag mounted on a tape comprises providing a bag comprising a first panel, a second panel, a first bag edge, a second bag edge, a bag bottom, and a bag mouth; gripping the bag between a first means for vacuumizing and a second means for vacuumizing; and moving the first and second means 20 for vacuumizing, and, while moving the first and second means for vacuumizing, drawing a vacuum through the first and second means for vacuumizing such that the bag disengages from the tape, and the bag mouth opens.

In a fourth aspect, a method of transporting a bag, the bag comprising a first panel, a second panel, a first bag edge, a second bag edge, a bag bottom, and a bag mouth, 25 comprises advancing a pair of pressers to the interior of the bag mouth, the bag mouth being in an open position and defining a first plane; moving the pressers transversely away S. from each other to press against the interior of the bag mouth; and activating a means for actuating to advance the bag, hel" by the pair of pressers, such that the bag mouth advances from the first plane to a second plane different from the first plane, wherein a method of transporting a bag, the bag having a first panel, a second panel, a first bag edge, a second bag edge, a bag bottom, and a bag mouth, comprising: a) advancing a pair of P:\OPER\A.,d2452116.r-s.doc-)409A)3 -3Apressers to the interior of the bag mouth, the bag mouth being in an open position and defining a first plane; b) moving the pressers transversely away from each other to press against the interior of the bag mouth; and c) activating a means for actuating to advance the bag, held by the pair of pressers, such that the bag mouth advances from the first plane to a second plane different from the first plane; wherein the pressers are advanced towards the bag mouth, in a path having a linear segment and a non-linear segment.

In a fifth aspect, an apparatus for transporting a bag, the bag having a first panel, a second panel, a first bag edge, a second bag edge, a bag bottom, and a bag mouth, comprises a presser assembly comprising a first shaft and a second shaft, the first and second shafts spaced apart from each other; a first cam and a second cam, the first and second cams spaced apart from each other and transversely mounted on first and second shafts respectively, a first presser and second presser, the first and second pressers mounted on first and second cams respectively.

o e *o a plate cam disposed intermediate the first shaft and a second shaft, the plate cam capable of causing rotation of the first and second presser through a 90' arc; and a means for actuating the presser assembly.

In a sixth aspect, an apparatus for loading a bag with a product, the bag having a firt panel, a second panel, a first bag edge, a second bag edge, a bag bottom, and a bag mouth, comprises a means for pushing the product; a means for actating the means for pushing the product; and a loading horn comprising a lower horn section, an upper horn section extending from the lower hor section at a pivoting joint, and an upper horn section having a transverse slot wherein the upper horn is capable of lateral expansion to accommodate the product.

Brief Descriptiou Of The Drains In the drawings presented by way of illustration ofthe invention: FIG.I is a perspective view of an apparatus for opening, transporting, and loading a bag; 15 FIG. 2a is a prpecve view of the apparatus for opaing a bag; FIG. 2b is an enlarged perspective view of aportio of FIG. 2a; FIG. 3ais a perspective view of a leading edge of a bag positioned between first and second vacuumizing means; FIG.3b is an enlarged perspective view of a portion of FIG. 2a;

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IG. 4 is a perspective view of a bag gripped between vacuumizing means; 20 FIG. 5 is a perspective view of a bag, wherein the bag has ben detached from the tapes by moving the bag away from the tapes; FIG. 6 is a perspective view ofan apparatus and method of opening a bag, wherein the bag mouth has been opened; and FIG. 7 is a perspective view of an apparatus for transporting a bag, with the bag mouth opened and detached fror the tapes; FIG. 8a is a perspective view of the presser assembly ofthe apparatus of Figure 7; FIG. 8b is a rear perspective view of the presser assembly, FIG. 8c is a perspective view of a follower forming part of the presser assembly; FIGS. 9a and 9b are diferent perspective view of barrel cams; FIG, 10 is a perspective view ofthe prsser assembly advanced to a position where the pressers have entered the bag mouth; FIG. 11 is a perspective view of the prsser assembly advanced to a position where the pressers are pressing against the interior of the bag mouth; FIG. 12 is a perspective view of the presser assembly at a partially returned position, where the pressers continue to press against the interior of the bag mouth, and the bag mouth is disposed in a substantially vertical plane; FIG. 13 is a perspective view of a loading apparatus in cooperation with apparatus for opening and for atrasporting a bag; FIG. 14 is a perspective view of a loading apparatus; and FIG. 15 a perspective view of a loading apparatus with a loading horn in an open position.

Descriotion Of The Prfrred Embodimts The invention involves in three aspects three functioos; namely, bag opening, bag transporting and bag loading.

With reference to Figure 1, these function axe implemented with a bag opening apparato a bag transporting apparatus and a bag loading apparatus each are described in detail below.

*An~na *Bag 9Pening Apaaus Ill With referenceto Figures 2a and 2b, the bag opening apparatus comprises a first means for vacuumizing a second means for vacuumizing an actuator and a bag platform [71 which accommodates an imbricated bag mounted on tapes [9 and 10]. The actuator can be any suitable conventional device, mechanical, pneumatic, hydraulic, electramechanic, etc. which serves to selectively advance or reract other companents of the bag opening appara- .Bag [8 is preferably imbricated or shingled with lie bags from a bag supply box [12).

A bag typically includes a first panel and a second panel (see Figure 6) on the opposite side of the bag from first panel Each panel can be regarded as having afirst and second end, and a first and second lateral cdge. As viewed in a substantially lay-flat ccuditio; the two panels each prefrably have substantially the same length and width. Respective cammunicating first edges of the first and second panels form a first bag edge A second bag edge [53] is foanned by respective camunicating second edges of the first and second panels. A bag bottom [55] is formed by respective communicating first ends of the first and second panels.

A bag mouth [56] is fonezd by respective communicaing second ends ofthe first and second panels.

Bags are typically made as aide seal bags or end seal bags.

6 The side seal bag will have a factory-made heat seal at opposite bag edges. The bag bottom will be formed by the fold of film created during the extrusion of bag tubing duing manufacture. The opposite fold of fim is slit to form a bag mouth.

An end seal bag will have opposite bag edges frmd bythe fold of film created during the extrusion of bag tubing during manufacture. The bag bottom will be a heat seal. The bag mouth is formed by a tansverse cut in the extrded tubing.

In both of these cases, the bag is typically made from a long length of bag tubing.

It is of course possible to use this invention with other embodiments, such as two discrete film panels which are preferably of substantially the same size, and brought together and sealed along two edges and the bottom to form a bag. Thus, although each panel major wall) of the bag can be regarded as having a first d, first and second edges, and a second end, and although the bag edges are described as being joined portions of respective edges of the first and second panels of the bag, it will be understood that in fact a particular bag edge, bag bottom, or bag mouth can be farmed or derived cither from a true seal between two webs or panels of 15 film, or from a fold of an originally single web of film, such as the tubular extruded "tape" typi.

cal of many film maling operations.

Bags made from tubing at a proessor's facility, such as those made in accordance with US Patent No. 5,618,252 (Melville), incorporated by reference herein in its entirety, can also benfi t frdm the opening, rasporting and loading aspects of the present invention.

20 Also, pouches having seals on three sides thereof (other than the bag mouth side) can also benefit from the opening, transporting and loading aspects of the present invention.

The first and second means for vacuumizing have multiple vacuum ports [11] to secure a bag panel to the means for vacuumizng. In operation, a bag is opened by indeing a bag [8] so that the bag mouth [56] (best seen in Figures 6 and 7 in an open position) is preferably at or slightly above the top surface of the means for vacuunizing [4 and 5] as shown in Figures 3a and 3b. From this position, bag opening is accomplished by advancing the first and second means for vacuumizing toward each other, and gripping the bag as shown in Figure 4.

While m ainining cotact with the bag the first and second means for vacuumizing [4 and are moved away from tapes [9 and 10], thus stripping the bag from the tapes as shown in Figure 3. With vacuum activated, i.e. drawing the vacuum through means [4 and the motion of first means for vacuumizing is stopped, but the second means forvacuumizing continues its motion away from the tape to open the bag as shown in Figure 6. It is necessary that vacuum an the first and second means for vacuumizing [4 and 5] be drawn prior to their saparation, i.e. prior tothe point in time that the motion offirst means for vacuumizing stops, but the 7 second means for vacumizig continues its motion away from the ape to open the bag.

However, vacuum on the first and second means for vacurnizing [4 and.5] can be drawn at any time in the opening sequence after the bag has been initially indexed into position. Thus, depending on the embodiment, vacuum can be drawn through means [4 and 5] prior to when means [4 and 5] are brought together to gip the bag; or after means [4 and 5] are brought together to grip the bag; or in one embodimnt even after means 4 and 5 are initially moved together to detach the bag from the tapes [9 and 10]. In act, vacuum can be drawn almost contnuously through means [4 and although vacuum should be discontinued during the time that the opened bag is to be advanced by the bag transporting mean as described herein, and during the time that the next bag is to be advanced into position for opening, since continued vacuumization at either of these stages (which can be simultaneous) would interfere with the freedom of movemeat of the bag.

Bag Transporin A aratus (21 15 With referenc to Figure 7, the bag transporting apparatus comprises a preser assermbly [13] traversable on shafts [14 and 15] when actuator [16] is activated. The actuamr can be any suitable conventional device, mechanical, pneumatic, hydraulic, electromehanical, etc.

which serves to selectively advance or tract other components of th transporting apparatus.

Interactive with the presser assembly [13] is plate cam In apration, as actuator [16] extends (Figures 8 and 10), the presser assembly is caused to rotate about axis in direction The presser assembly is further illustrated in Figures Ba and Sb, showing pressers [18] mounted on barrel cams [19 and 20] which are travcrsable on shafts [21 and22] against spring pressure supplied by springs [23 and 24]. The pressers are depicted as paddles, but any suitable arms, blades, fingers, rods, or other prjections of any suitable geometry can be beneficially used provided they finction in cooperation with the other component of the bag transporting apparatus as described herein. Shafts [21 and 22] are mounted in housings [60 and 61] which rotate about axis when driven by cam follower Traversing motion of cam [19] on shafts [21 and 22] is controlled by cam groove [27] (see Figure 9b) interacting wth follower [28] (see Figure Sc) which can rotate around shaft Contact of follower [28] with cam [19] is maintained by a torsional spring (not shown]. As the cams [19 and 20] rotate in directon the cams move symetically towards each other for approxmately 90 degees of rotaion a which point cam follower [28] reaches a portion of cam groove [27] parallel with shafts [21 and 22], allowing the springs [23 and 24] to force the cams away from each other. As the bag trnsport sequence is described herein, it will be seen that the exut of the motion is constrained bythe bag being 8 transported. As the rotary motion is reversed, the camn follower [28] rotates about shaft [29], climbs the inclined portion ofthe cam graove [30, and reseats in the groove after approximately degrees of roation in the direction opposite to In operation, to transport a bag opened by the.bag opeaing means the actuator [16] is activated by suitable controls, causing the bag transporting apparatus to traverse shafts 114 and 15] with cam (171 ffeccting a rotation around axi and cams (19 and 20] narrowing the distance between pressers [18] to a width sufficient forthe pressers 18 to partially enterthe bag s(8] as shown in Figure Just prior to completing the rotation into the bag springs [23 and 24] spread the pressers (13] transversely away from each other, thus gripping the interior of the bag mouth 56 as shown in Figure 11.

By rtractig actuator the preisgn [18] reverse their rotation, bringing the bag opening with its cross section initially in a substantially horizontal position [See Figure 11, showing a dotted oval pattern 12a indicating the horizontal plane ofthe bag mouth] to a substantially verti- 15 cal position a shown in Figure 12.

*The bag transporting apparatus thus allows the bag to be transported such that the plane defined by the bag mouth changes fromn a horizontal to a vertical position From the position shown in igur 12, continued rcwaction of the actuator [16] pulls the bag onto the hom 50 as shown in Figure 13, completing the transporting ofthe bag.

It should be noted that the plate cam 17 controls the rate of rotary motion of the paddles 18 around 'axis This maoion could altantively be controlled with a rotary pneumatic cylinder, a servo motor or mechanical linkage, The plate cam 17 is preferable because of the fictxibility it allows in designing the path of the paddles. The same function can be achieved using a ,servo motor, although this would incur a greater expense. The path of the paddles could be reproduced by the use oafa rotary actuator or mechanical linkage, but only with difficulty.

S**

Bar Loadin Annaratus 3 With referecc to Figure 14, the bag loading means consists of a product pusher [31] with its actuator a lower horn section and an upper horn section The actuator can be any suitable conveational device, mechanical, pnetmatic, hydraulic, electromechanical, etc. which serves to selectively advance or retract other components of the loading apparatus.

The upper horn section [34] can pivot around axis and with slot section [36] is expandable laterally. These pivoting and lateral expanding features allow the horn [50] to accom- 9 modate a wide variation in product shapes. These products are preferably various subprimals of fresh red meat, smoked and process meat poultry, cheese, and the like.

To load a bag, a product is positioned in the hopper section or cavity frmed hi the lower horn section and actuator [32) exends the product pusher [31] forward, foring the product into the bag. The smooth tapered form of the upper and lower horn sections [34 and 33 respectively), and the pivot and lateral expansion features described above, allow the product to be pushed into the bag with little resistance. In addition, the tapered shape of the horn provides for a relatively small cross-section at the end of the born to facilitate bag loading.

Several advantages are obtained by the present invention. The invention addresses the problem of stuck bag lips, especially when using end seal bags, by removing the bag from the tape prior to opening. Also, air inflation of the bag, although useable in connection with the invention, is no longer required.

In addition, the final dimensions of the bag opening are controlled by the disposition of the first and sccond means for vacuumzing, and not by the tape spacing, eliminating the need to have 15 multiple tape spacings for different product profiles, as is the case when inflatin a bag on conventional opening systas.

The invention places the unopened bag in a vertical position, eliminating "bag knock off', in which discharged packages traveling over the bag train can dislodge yet unopened bags f u r ther down the bag train. Also, the overall length ("footprint") of the equipment is reduced without sacrificing the ability of the equipment to load bags in a horizontal mode.

The bag transporting apparatus is capable of pulling and, with its pressers, securing from 67% .to 100% of the bag length onto the loading horn. This facilitates loading by shielding the bag mouth and a majority of the bag from th product which, otherwise, would strip the bag fom the S" horn without seating in the bottom of the bag.

Loading force and severity of stuffng is reduced by the hornm by utilizing a polygonal shape which more closely matches the product shape; utilizing a gradual taper in the horn geomety; and incorporating flexible members.

Other components typical of a bag loading system can be used with beneft in connection with the present invention. These are well known and conventioal and need no further deacription for those skilled in the art A bag as shown in the drawings is preferably one of a plurality of like bags stacked in imbricamed (shingled) fashion in a bag loading system. An imbricated taped bag arrangement is well known in the art. When used in a vertical opening system as described heren, the adheive tapes can themselves functionas the m s for supporting the bag, or a separate plate, baffle, or the like can be used, in any suitable orientation. Bags can be advanced by any suitable means, such as by a conventional taped bag indexer (not shown), or any suitable device or process. The bags can be shingled 'frward", i.e. the topmost bag in the stack of bags is furthest advanced or forward, and closest to the means for opening. Any subsequent packaging steps, such as vacuuizing, heat scaling, hrinkig, etc. can be performed as desired.

Any films, especially thermoplastic films such as olefinic films with or without oxygen barrier fimctionality, can be used with benefit in this invention. These films are made by extusion coating, coextrusion, lamination, or other suitable processes. Especially preferred for many applications are films comprising an outer layer, an intermediate layer, and an inner layer. The materials of the outer layer are often chosen for abuse resistance and/or sealability, and can be chosen from any suitable polymeric materials such as polyolfins, especially ethylenic polymers and copolymers, polypropylene, polyesters, polyamides, and the like. The inner layer materials, often chosen for sealability, can be any of the materials described for the outer layer. The inter.

mediate layer materials are often chosen for their barrier qualities barriers to oxygen, mois- 15 ture, carbon dioxide, etc.). Preferred materials include polyvinylidene chloride polymers and copolymers, ethylene vinyl alcohol copolymer, polyvinyl alcohol, polyamide, polyester, acryiani.

trile, and the like. Bags are preferably heat shrinkable, and preferably at least partialy c: rosslinked.

Itis to be understood that variations of the present invention can be made without departing from the scope ofthe invention, which is not limited to the specific mbodiments and ex- S amples disclosed herein, but extends to the claims presented blow.

Although the invention as described herei is preferably used in connection with taped bags (a very common commercial bag system), it can be beneficially used even without the use of adhesive tapes. Wth respect to the opening method described herein, the opening of a bag without an adhesive tape can still benefit from the use of the first and second means for vacuuming to open a bag, in any of the cmbodiments described herein. The same is true for the transporting and loading apparatus and methods disclosed herein, although of course these are already described herein with respect to a bag which has already been detached from the tapes.

The methods and apparatus described and claimed herein can be used in connection with bags with panels of uneven length, and in connection with bags with curved bag lips.

Although the preferred use of the invention is in connection with the opening of bags held in a substantially vertical position horizontal bag mouth), followed by transporting to a substantially horizontal position for the bags vertical bag mouth), other orientations of the bag and bag mouth, between horizontal and vertical, ar also possible.

P:\OPER\Axd2452116-div.doc-28/08/01 -11 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

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Claims (1)

12- The claims defining the invention are as follows: 1. A method of transporting a bag, the bag having a first panel, a second panel, a first bag edge, a second bag edge, a bag bottom, and a bag mouth, comprising: a) advancing a pair of pressers to the interior of the bag mouth, the bag mouth being in an open position and defining a first plane; b) moving the pressers transversely away from each other to press against the interior of the bag mouth; and c) activating a means for actuating to advance the bag, held by the pair of pressers, such that the bag mouth advances from the first plane to a second plane different from the first plane; wherein the pressers are advanced towards the bag mouth, in a path having a linear segment and a non-linear segment. 2. The method of claim 1 wherein the pair of pressers comprises a pair of paddles. 3. The method of claim 1 wherein the intersection of the first plane and the second plane defines an angle of greater than 0' and less than 1800. 4. The method of claim 1 wherein the intersection of the first plane and the second plane defines an angle of 9 0 'C. The method of claim 1 comprising advancing the pair of pressers towards the interior of the bag mouth, the bag mouth being in an open position and defining a 20 first plane, wherein the pair of pressers move towards each other as the pressers are advanced towards the bag mouth. 6. A method of transporting a bag according to claim 1 and substantially as hereinbefore described with reference to the accompanying drawings. 25 DATED: 4 September, 2003 by DAVIES COLLISON CAVE Patent Attorneys for the Applicant(s): CRYOVAC, INC.