METHOD AND APPARATUS FOR CONTINUOUS FORMATION OF RECLOSABLE ARTICLE WRAPPERS
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to method and apparatus for package making and the article wrappers made thereby, and more particularly to the formation of reclosable plastic film bags.
Description of the Prior Art
Today, more than ever, there is an increasing demand for articles which have been shipped from the manufacturer, prepackaged. This is particularly true in the area of preprocessed food articles where convenience, sanitation and storage before and during use are important. For example, plastic film wrapped preprepared foods such as frozen waffles, portion controlled meats, individually frozen fruits and vegetables, etc. are very much in vogue and demand by the consumer.
Plastic film bags and the apparatus and method designed to package articles in these bags at the factory are thus also in demand. The greatest problem still unsolved in this industry relates to the efficient production of low cost reclosable bags. By reclosable bags is meant wrappers or bags which may be opened by the ultimate user to remove portions then be resealed to permit storage of unused contents. There are, currently, only three types of reclosable bags in general usage today. The first type is commonly called the sandwich bag in which the bag incorporates a reverse fold which the consumer employs to reclose the bag. o seal is provided. This type of bag is in widespread use for sandwiches and the like, hence the terminology.
OMPI , WIPO
The second type of reclosable bag employs an extruded bead along one edge of the wrapper intended to mate with an extruded channel on an adjacent film section. These bags are currently sold under the tradena e "ziploc" and operate by having the user, by finger, pressure, force the bead into the channel to effect closure of the wrapper.
The third type of bag utilizes double face tape,, that is, tape which is sticky on both faces. In use, this bag is sealed by pressing the bag faces together along the open edge and the double face tape, permanently fastened on a bag face, engages the other bag face, sealing the two together. This bag has three disadvantages which have discouraged its general acceptance. First, providing an adhesive face is an expensive process and doubly so when two adhesive faces are required. Secondly, an adhesion problem often develops in that the tape is no more inclined to stick to the "permanently" bonded bag face than to the "temporarily" bonded bag face and thus, a user may find upon opening the bag, that the bag opens along one face part way and the other the rest of the way making it impossible to remove the bag's contents. Thirdly, to the extent that the bag is formed using a film hot wire sealer, a poor seal results along the bag edge along the tape edge because double face tape is not amenable to this form of sealing. All the aforementioned article wrappers, or bags, thus have distinct disadvantages. The fold-over wrapper really does not seal the contents and therefore spoilage or staleness is a problem with regard to food, together with the problem that the contents themselves may slip out between the folds of the wrapper. In the second type of wrapper, the extruded bead and channel are extremely costly to produce and, therefore, these bags have been limited to applications where the intrinsic value of the contents justifies the high price. They are also difficult to use, requiring good eyesight to align the bead in the channel and
finger dexterity to force it in place. Finally, double faced tape bag closures do not seal consistently and are also very expensive.
All of the foregoing demonstrate the continuing need for method and apparatus particularly suitable to a high speed line to produce a reclosable wrapper suitable for all applications and which is inexpensive to produce, simple to use and has a low failure rate.
SUMMARY OF THE INVENTION
The aforementioned prior art problems are solved by the apparatus, method and wrapper of this invention wherein the wrappers, a method, and the apparatus for their production is disclosed. In the method of this invention, film, preferably plastic film, is continuously payed off a roller. The advancing film sheet is prepared to receive tape. This process step may be performed several ways. In the preferred embodiment, the advancing film sheet contacts parallel spaced-apart blades which cut from this film a longitudinal band to create a hiatus and leave parallel spaced-apart strips of advancing film. Alternately, a single blade cut may be utilized following which the film is separated to create the parallel spaced-apart strips. Simultaneously with this film preparation step or stage, tape with one adhesive face is also payed off and continuously advances. The tape is of a width exceeding the width of the band cut from the film strip and the tape is brought into registration with the newly created film opening. The tape is then applied to the film, the edges of the tape pressing sufficiently to achieve permanent adherence- to the film face, sticky side down, thereby producing a re-combined advancing film strip with a band of adhesiveness therewithin. An alternate method utilizes tape, one edge of which
OMPI
is dry. In this method, film strip, preferably prefolded and also preferably off-center or J-fold, is payed off to meet the advancing tape. The tape's adhesive edge is applied to the film edge resulting in the dry edge overhanging, or projecting from, the film strip edge to form a lip. In a subsequent step, if nonfold film has been employed, the advancing tape banded film is joined along its transverse edge with another continuously paying off film strip and the article to be wrapped advances on a conveyor to a point between the two film strips.
The film strips are then joined on at least all non- tape edges in a conventional manner, as by hot wire sealing, and severed to produce a reclosable bag and create a new transverse sealed edge for the next advancing package. All edges may be joined and perforation used to provide an extra seal if desired. Where article packaging is included, the finished product of the method is a wrapped package.
Where single fold film has been used, the article wrapping stage involves slipping the article between the fold and is followed by the sealing and separating step.
The package itself thus produced in the first two described embodiments is a generally rectangular bag sealed permanently along three edges but which includes adjacent the other edge, and running its full length, the band of adhesiveness produced as previously described. In the example of the dry tape edge, the film strip edge created by the dry tape edge provides grasping means for the fingers to aid in opening the bag or wrapper.
Accordingly, it is an object of this invention to provide a method and apparatus for the production of inexpensive and easy to use reclosable article wrappers.
It is yet another object of this invention to provide a method and apparatus which are suitable for a high speed, continuous operation. Ifc i-3 Yet another object of this invention to provide
an apparatus and method easily adaptable to varying size wrappers, and which is independent of variations in size and shape of* the articles to be wrapped.
It is yet another object of this invention to provide a method and apparatus adaptable to either single face adhesive or dry edge tape.
It is another object of this invention to provide a method and apparatus equally adaptable to film sheet where the film pays off either as a single sheet or a folded sh.eet.
It is still another object of this invention to provide a package wrapper which is easy to use by consumers without regard to their age or finger dexterity.
These and other objects will be more readily ascertainable to one skilled in the art by reference to the accompanying drawing and exemplary embodiments that follow.
BRIEF DESCRIPTION OF THE DRAWING(S) Figure 1, and the subsequent method drawing, show flow diagrams of the method of this invention with abreviated apparatus indicated to simplify and better illustrate the method.
Figure 2 illustrates an alternate embodiment of the method of this invention. Figure 3 illustrates yet another alternate embodiment of the method of this invention.
Figure 4 shows an alternate method adapted for J- folded (off-set) film sheet with an added edge strip.
Figure 5 illustrates a partial enlarged view of the film strips utilized in the method of Figure. 4 just before tape application.
Figure 6 shows another alternate embodiment utilizing J-fold film plus dry edge tape.
Figure 7 illustrates a bag made by the method shown in Figure 6 with one edge peeled back.
Figure 8 shows an alternate method, in partial, in which a step of fabricating the dry edge from an otherwise all adhesive tape is provided.
Figure 9 illustrates a front view of the apparatus of the preferred embodiment of this invention.
Figure 10 shows a view taken on lines 10—10 of Figure 9.
Figure 11 is an isometric enlargement of a cutter and the tape application portion of the apparatus. Figure 12 illustrates an alternate embodiment of the cutter.
Figure 13 illustrates a reclosable bag made by the apparatus and method of this invention.
Figure 14 is a cross section taken along lines 14—14 of Figure 13.
Figure 15 shows an article wrapper produced by an alternate method and apparatus of this invention.
Figure 16 is a cross section taken along lines 16—16 of Figure 15. Figure 17 is yet another alternate article wrapper of this invention.
Figure 18 is a cross section taken along lines 18—18 o.f Figure 17.
Figure 19 shows yet another alternate article wrapper o this invention.
Figure 20 is a cross section taken on lines 20—20 of Figure 19.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) Referring now to the drawings, and more particularly to Figure 1, a flow diagram is shown of the method of this invention in which film sheet or strip 10 is shown advancing from roller 12. Film 10 passes over guide bar 14 and advances to cutter 16. Cutter 16 includes parallel blades 18, and blades 18 cut from film sheet 10 a longitudinal
"ξT ET, O PI
strip of film 20 which is discarded. Sheet 10 continues advancing over guide roller 22 and it may be seen that the advancing film now includes a hiatus 24 created by the action of cutter 16. As film sheet 10 advances to guide roller 26, it meets adhesive tape 28 which has been simultaneously advancing by paying off from spindle 30 over guide roller 29 and is brought in registration with hiatus 24 by guide bar 32.
Tape 28 has a sticky, or adhesive, side 34 which is applied to film sheet 10 by presser bar 80. Advancing film sheet 10, following the application of the tape, moves forward now as a re-combined sheet with a band of adhesiveness therebetween created by the band of tape. Advancing sheet 10 passes over guide rollers 38, 40 and 42 to position it in relationship to advancing packages(s) 44 which are being conveyed forward in the direction indicated by arrow 46.
Simultaneous with the aforementioned process, another film strip 48 is being payed off and advancing to meet film strip 10 at a position below advancing packages 44. Film strip 48 moves over guide rollers 50 and 52 while film sheet 10 moves over guide rollers 54 and 56, both of which operations cause the film to be disposed about the package to be wrapped. Package and film advance together through a sealing and severing operation at station 51. Station 51 may be a bar-sealer and operate by a conventional heat sealing and severing step well known in the art. After moving through the sealing and severing station 51, package 44 is shown exiting the station as indicated by arrow 53 to emerge as a rectangular wrapped or bagged article incorporating therein an adhesive strip made by the process of this invention.
Referring now to Figure 2, an alternate embodiment of the method of this invention is illustrated in which a single cutter is utilized to slit the film after which the
QMPI
film is spread apart and the adhesive tape thereafter applied. In Figure 2, film 10 advances from roller 12 and over guide roller 14 as in Figure 1. In Figure 2, however, cutter 17 — a single bladed cutter — replaces the cutter 16 of the previous method. In Figure 2, cutter 17 makes a single cut of film 10 which thereafter advances gradually being spread apart until it reaches roller 22 over which it passes upward to roller 26 where it meets advancing tape 28 unwinding from spindle 30 and passing over guide rollers 29 and 32 to tape guide 36, all as was illustrated in Figure 1. At this point, hiatus 24, created in film strip 10 by the cutting and parting action of the film, produces parallel advancing film strip in the same fashion as has been illustrated and described in Figure 1. Tape 28 is applied to film strip 10 which advances thereafter in, for example, as was illustrated in Figure 1 to be formed into an article wrapper, but which step is omitted in Figure 2 as repititious.
Referring now to Figure 3, yet another alternate embodiment is .illustrated in which the cutting step is omitted and the film strip from its inception comprises two individual rolls of film, strip 8 and strip 9. In Figure 3, film strips 8 and 9 pay off simultaneously from their respective spindles passing over guide roller 14, advancing therefrom in parallel spaced-apart relationship to create hiatus 24. Again, as has been described in Figures 1 and 2, the advancing film strips 8 and 9 pass over guide roller 22 where they meet tape 28 advancing from spindle 30 over guide rollers 29 and 32 to be joined by presser bar 36 at guide roller 26 to combine the film strips into a continuous sheet with an intermittent adhesive strip created from the combination. As in Figure 2, the succeeding steps of forming the article wrapper and wrapping a package therewith have been omitted as repititious. Referring now to Figure 4, yet another alternate
method of this invention is shown wherein film strip 10' is provided as a folded sheet with an off-set center fold along edge 90 to create thereby film extension 92. Simultaneously, narrow strip 94 pays off to be positioned by guide means 96 on top of film extension 92. The two film strips, 10' and 92 advance together to meet tape 28 advancing from spindle 30 as has been previously described. Tape 28 advances on the guide roller 32 through tape guide *36 over guide roller 26 to meet the advancing film and, thereafter the film with tape applied proceeds through bar- sealer 100. It should be noted that the article to be wrapped may be inserted either before or after the edge sealing step.
The exact positioning of tape 28 is best illustrated with reference to Figure 5 which shows tape 28 positioned to span film strip 10' from its upper edge 98 across film extension 92 to overlap on narrow film strip 94. In Figure
5, the spatial relationship of tape 28 to film strip edge 98 and gap, or hiatus, 93 are more clearly shown. Bar-sealer 100, operating in a conventional manner, heat seals the edges to provide a bag in which film extension 92 and strip
94 are provided in order for the user to grasp the bag by these edges, pulling it apart. It should be noted that with this method, it is possible to utilize, as the narrow film strip 94, a piece of reinforced film which would, for example, be particularly beneficial where the bagged articles are to be hung on a display stand and a reinforced top is useful to prevent premature tearing.
Referring now to Figure 6, it may be seen that in this embodiment that narrow film strip 94 is omitted. In Figure 6, as in Figure 4, film strip 10' is provided as a J- folded or off-center folded tape which advances from its spindle as previously described. In the embodiment in Figure 6, however, adhesive tape 28* is provided as a dry- edged tape, meaning that part of one of the surfaces 102 is
an adhesive segment as previously described, but segment 104 is non-tacky or dry-edged. Tape 28' advances over guide roller 92 and under tape guide 36 where the tape is applied to span edge 98 of film strip 10' and seal it to film extension 92 as may be more readily understood from consideration of Figure 7.
In Figure 7, a wrapper produced by Figure 6 is illustrated with an edge peeled back to show the relationship of the adhesion of tape 28* to film strip 10*. In Figure 7, dry edge 104 and sticky edge 102 are shown in relationship to upper film edge 98 and film extension 92. Sticky edge 102 is shown in this view also in phantom to better illustrate its positioning.
Referring now to Figure 8, an alternate embodiment of the method illustrated in Figure 6 is shown in which dry edge 104 previously described is produced by utilizing chalk 106 whose function is to contact adhesive tape 28' as it unreels to leave a deposit on one edge of the film as illustrated to create dry edge 104 on one segment of the tape while leaving sticky- segment 102 intact.
With regard to the apparatus of this invention and now referring to Figure 9, a front elevation of the apparatus of the preferred embodiment of this invention is shown. In Figure 9, film sheet 10 is shown behind the apparatus paying off from roller 12 and advancing behind the apparatus as shown by arrows 11, coming over the top at guide bar 14 as indicated by arrow 55. The advancing film reaches cutter 16 adjacent to guide roller 26 as shown from the front with blades 18 in spaced-apart relationship. Details of cutter- 16 are more readily apparent in reference to Figures 10 and 11 and will be discussed with reference to these Figures.
In Figure 9, waste tape 20 which is the film band or strip cut from advancing film sheet 10, is shown conveyed into conduit 57 and moved toward disposal by the application
of a slight vacuum in the conduit as indicated by vacuum tube 49. Film sheet 10, now parallel strips of spaced-apart film, advances over guide roller 22 and upward over guide roller 26 in preparation for the application of adhesive tape 28. After tape 28 is applied to strip 10, strip 10 advances over guide roller 38 to subsequent wrapper forming stages (not shown).
Tape 28, shown in edge view in Figure 9, advances from spindle 30 over guide 29, shown supported by brace 31 in this view. The advancing tape passes over reel 33 to meet film strip 10. Details of this apparatus are more clearly visible in Figures 10 and 11 and will be discussed in relationship to these Figures. Also visible in Figure 9 is brace 66 which supports slotted brace 62 by nut 64. Brace 62 in turn supports cutter 16 by pin 63. Also shown are bracket 74 which holds tape guide 36, and spindle 70 on which tape guide 36 is mounted and held by nut 72. All these parts are more clearly understood in their operating relationship in regard to Figures 10 and 11 and are discussed again in connection with these Figures.
Guide bar 32, which supports reel 33, is also shown in front elevation in Figure 9 as well as an end view of brace 31 which supports this section of the apparatus through a connection to housing 59 behind guide bar 32, not visible in Figure 9). With reference to tape 28, also shown are brace 61 which holds spindle 30, and hinge 58 through which spindle 30 may be conveniently moved to facilitate loading and unloading the tape. Also, as part of housing 59, various washers and nuts 60 holding the various rollers, etc. to housing 59 are shown and also bracket 47 which adjustably supports conduit 57.
With reference to Figures 10 and 11 which will be discussed together. Figure 10 is a cross section taken on lines 10—10 of Figure 9 and Figure 11 is an enlarged fragmentary showing details of cutter 16, guide bar 32 and
OMPI ^ IPO r? l -
tape guide 36. In these two Figures, film strip 10, shown advancing from behind housing 59 in the Figures, moves forward over guides 27, 15 and 14 as shown in Figure 10 while tape 28 (shown in edge view) unwinds from spindle 30 as previously described.
The details of the advancing tape being applied to the film may best be seen with reference to Figure 11 where tape 28 is shown advancing over reel 33, shown in its greatest detail in this Figure, down and under tape guide 36 where it meets advancing film strip 10. Reel 33 is supported by guide bar 32 and brace 31. In Figure 11, part of tape 28 is shown in broken view to permit a better view of spindle 70, nut 72 and bracket 74, which part supports tape guide 36. Presser bar 80, whose function is to firmly seal tape 28 to film strip 10, is also shown in more detail in Figure 11. Presser bar 80 may be seen rotatably supported by bracket 83, which bracket is, in turn, secured to brace 82 and through brace 82 by connector 86 to brace 84. Brace 84, shown in partial view, attaches to housing 59 at a point not shown in this Figure, but which may be seen in Figure 10. Brace 82 and bracket 83 are also shown in cross section in Figure 10.
Figure 10 also shows a side elevation of conduit 57 and vacuum tube 49 with bracket 47 which supports it and into which waste film strip 20 is conveyed. Also, this Figure shows a side view of roller box 88 which supports film strip roll 10. Figure 10 is also the best view to see the overall shape and function of housing 59 from which the various braces and brackets previously discussed suspend or are mounted, such as brace 31 and guide bar 32 which support the tape assembly. Also, spindle 30, held by brace 61 and hinges 58' may be seen. Figure 11 shows principally in closeup, however, cutter 16 which has spaced-apart blades 18 which slice film strip 20 from film strip 10. Blades 18 are shown mounted in blade housing 19 which in turn is pinned
with pin 63 to brace 62. Brace 62 is slotted and by loosening nut 64, brace 62 may be adjusted either vertically or pivoted. Brace 62 is shown mounted to brace 66 which in turn connects to housing 59 (not shown). Figure 11 also shows blades 18, their housing 19, pin
63, and supporting braces 62 and 66.
Cutter 16 is but one embodiment of the cutting function. Referring now to Figure 12, a fragmentary view is shown of alternate~ cutter 108. Cutter 108 is a pair of spaced-apart rotary blades mounted on shaft 110 which is in turn connected to housing 59 (not shown). In this alternate embodiment, cutter 16, together with its supporting braces, is eliminated. Cutter 108 is mounted on shaft 110 to permit it to rest against guide bar 22. That is to say, in this embodiment, the cutting' function is set lower in the apparatus and guide bar 22 not only guides but provides a rest function against which the blades of cutter 108 may operate.
Referring now to Figure 13, the first of several reclosable bags made by the apparatus and method of this invention are shown. Article wrapper or bag 114 is shown in Figure 13. Bag 114 is a pocket of film and includes heat- sealed edges 116 and heat-sealed or folded end 118. Bag top 120 is shown separated from bag bottom 122 to reveal tape 28 with sticky edge 102 in a position to be operably attached to bag top 120.
Referring now to Figure 14, a section taken on lines 14—14 of Figure 13, it may be seen that bag top 120, in this example, extends beyond bag bottom 122. This overlapping arrangement is optional and the two bag edges could be even. In Figure 14, it may be seen that tape 28 is attached to bag 114 by being applied to the outside of bag bottom 122 overlying hiatus 24.
Referring now to Figures 15 and 16, another article of this invention is shown. Bag 124 is shown, again in a
pocket of film, including heat-sealed edges 126 and bag end 128. Bag 124 also includes perforated leading edge 132 which, when torn apart by the user as illustrated in Figure 15, would leave a bag top 134 and bag bottom 136 of equal length. Edges 138 and 140 created by this tearing away of leading edge 130 are easily separable by the thumbs of the user who, when pulling them apart with a continuing pulling motion, would thereby pull bag top 134 away from bag bottom 136 along the seal created by tape 28. Figure 16 shows a cross section taken on lines 16—16 of Figure 15. Perforated edge 132 shows in this view as well as the relationship of tape 28 to bag top 134 and bag bottom 136 and hiatus 24.
Bag 124 is particularly useful for applications where it is desirable to maintain article integrity while on the shelf. For example, in grocery stores, the user would know that the bag had not been tampered with and that, therefore, the contents were clean and sterile as delivered from the manufacturer. The creating of a bag with four heat-sealed edges is known in the art as well as creating a bag with perforation. In this invention, however, this type of bag now includes tape 28 incorporated therein in the manner shown and previously described.
Referring now to Figures 17 and 18, yet another embodiment of the wrapper of this invention is shown. In Figure 17, bag 142 made from off-center folded film sheet is shown together with dry edge tape 28' which has been applied to one of the bag edges. In this Figure, bag 142 is shown with top 144 terminating with tape 28' whose leading edge 148 is dry, or nonstick. Adhesive edge 150 performs the function of sealing the two bag sides together while dry edge 148 provides the finger hold necessary to readily open the bag.
In Figure 18, a cross section taken on lines 18—18 of Figure 17 is shown which better illustrates the relative
position of bag top 144, tape 28* and the split tape face resulting in adhesive side 150 and dry edge 148.
Referring now to Figures 19 and 20, still another alternative bag 152 is shown. In bag 152, the bag, during its assembly, is folded along edge 154 to produce thereby a flap 156 in bag top 151. Flap 156 and bag 152 include sealed edges 158 and flap 156 shows tape 28 superimposed thereon with a peeled back edge to show adhesive face 160.
In Figure 20, a cross" section taken on lines 20—20 of Figure 19 shows the relationship between tape 28, bag top 141 including flap 156, bag bottom 153 and tape face 160 and edge 154.
There are many variations which may be practiced within the scope of this invention. For example, in the apparatus, two different cutters — one a blade and one a wheel — were illustrated. It is possible, in those applications where a strip is to be cut from the film, to replace the cutter with a punching apparatus which, instead of cutting a strip from the film, would merely punch a line of closely spaced together holes in the film. These holes would provide the hiatus through which the tape would project its adhesiveness and perform its function of adhering the film edges together. An advantage of this type of quasi-cutting would be that it would eliminate any difficulties that might be encountered in holding the film strips parallel until they can be recombined by the tape. Secondly, the film remaining between the punched holes, though miniscule, would nonetheless perform as a reinforcing of the film strip which is useful in a high speed operation where film damage might be a problem.
Also, it should be realized that in, for example, the method shown in Figure 4 (and others), instead of J-folded film, center folded film would be utilized. A rotary perforating blade (well known in the art) would be used to perforate both layers of film near the folded edge and
parallel to it. A strip of film would be cut through one layer of the fold (by using a separator plate between the film layers) as previously shown. The article to be wrapped would be inserted through what would be an open bottom. An L-sealer (right angle sealer) would be employed to simultaneously seal and trim side plus bottom.
Having now described and illustrated my invention, it is not my intention that such description and illustration be limiting as to the scope of the invention, but rather that the invention be limited only by a reasonable interpretation of the apended claims.