Apparatus for making reinforced reclosable package seals

158503/2

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APPARATUS FOR MAKING REINFORCEDRECLOSABLE PACKAGE SEALS jnmNb pnnn two»

Eitan, Pearl, Latzer &amp;amp; Cohen-ZedekAdvocates, Notaries and Patent Attorneys P-3330-IL2

REINFORCED RECLOSABLE PACKAGE SEALS

This application is a continuation in part of copending application number08/861,576 filed on 05/22/97, now U.S. Patent No. 5,944,425

This invention relates generally to packaging systems, and more particularly toflexible packages of the kind shown in my copending earlier application further havinga primary reinforced openable and resealable interlocking closure which may befurther provided with hinge formations and V-notch reinforcements spaced along thelength of the closure, the resealable interlocking closure having male and female partswith the primary reinforcement being formed in the female part. Several ways forforming the primary reinforcement are disclosed. Also disclosed are methods andapparatus for making such packages and closures from a continuous web of flexiblefilm, the closures being formed during package formation at line speed.

BACKGROUND OF THE INVENTION

As described in my earlier application, in the past, the methods of makingreclosable flexible packages have involved either the extrusion of the locking structurealong with the film extending longitudinally in the direction of film extrusion along theopposite edges of the film, or by heat sealing a separately made resealable closurestructure to the package film. The first type of package formation results in packageshaving the reclosable feature in the consumer non-preferred position along the longedge of the package, while the second type of package formation results in packageswhich are expensive to make because of the need to inventory and store rolls of theseparate resealable closure structure for attachment to the packaging film and theneed to insure that the separately obtained packaging film and closure structure aremade of compatible materials. Shown and described in my earlier application is aresealable interlocking closure of the same general kind as shown and described inthis application, but which does not include the improved features of the presentinvention, namely, the primary reinforcement in the female part and the hingeformations and V-notch reinforcements, each of which contributes to making asuperior closure.

SUMMARY OF THE INVENTION

As in the earlier application, the package and system according to the presentinvention also utilizes a novel converter device mounted atop or adjacent to standardpackaging apparatus to form a small amount of the running packaging film Into theresealable closure structure as an integral part of the film oriented in one form in theconsumer desired direction extending transversely to the long dimension of thepackage. The converter functions with both horizontal and vertical form/fill/seal 1 wrapping machines and with overwrap packagers, and uses diverse double sided heatseal packaging films such as polypropylene, polyester, polyvinyl chloride, high andmedium density polyethylene, thermoplastic heat seal coated non-plastic films, andvarious film laminations.

In the previously referred to one form of the invention the package formationbegins by feeding the plastic film, as it unwinds from the storage roll, into the theconverter, where the film is automatically layered by fanfolding across the entire widthof the film to form a stack. Layering other than by fanfolding to form a stack may beutilized, as for example heat sealing a strip of heat sealable material to the packagingfilm, but fanfolding is a convenient, fast and economical method of stack forming.The number of folds will vary depending on the thermoforming properties andthickness of the particular film being used. The stacked layers are immediately edgeheat sealed together widthwlse of the running film forming a multilayered strip oftypically one half inch width extending completely across the film width In plane withthe film, the strip layers being unsecured to one another between the edge seals.Next, the multilayered strip carried by the packaging film is abraded on one surface toremove the thermoplastic heat seal coating, in one case except at one end, and inanother case except at both opposite ends, and leave the remainder of that surface ofthe strip uncoated, the film being then passed into the package forming apparatuswhere the product wrapping and longitudinal package sealing takes place. Afteremerging from the package forming apparatus the package ends are sealed and thepackage resealable locking feature is formed in the stacked layers of film or in thestrip which has been heat sealed to the film, with or without the hinges and the ν'-notch reinforcements as desired. The entire process takes place at packaging linespeed. - In another form of the invention the package formation begins by feeding theplastic film, as it unwinds from the storage roll, into the the converter, where the filmis first longitudinally folded along one edge before being fanfolded as previouslydescribed. A modification of this form of the invention is provided by adding a strip offilm to at least one longitudinal marginal edge of the web in lieu of edge folding, thestrip being of substantially the same width as the package longitudinal seal. Thepoint of application of the strip determines the form of the primary reinforcement ofthe interlocking closure.

In the foregoing described forms of the invention the reinforced resealableinterlocking closures are all formed transversely to the direction of film flow. In oneother form of the invention the reinforced resealable interlocking closures are formed 2

In line with the direction of film flow along one edge of the package and may beformed in either of the two previously described ways, by fanfolding or by adding astrip of heat sealable material to the packaging film. In this form of the invention theprimary7 reinforcement extends the full length of the female part of the resealableclosure.

My earlier patent application discloses an interlocking closure similar to that ofthe present invention, except that in that package structure the male and female partsare reversed as compared to the present invention, and as previously noted the hingestructures and V-notch reinforcements are absent. In the present invention, thefemale part of all embodiments of the invention except one is formed on the face of thepackage where the longitudinally extending package seal is formed. This is a verysignificant difference, In that by so forming the female portion to include thelongitudinally extending overlapped central region of the package, it includes in itsstructure several times the number of plies In the male part that interlocks with it, thenumber of additional plies being determined by the particular form of the inventionutilized. In the form of the invention where the Interlocking closure Is along one edgeof the package, the female part of the closure can also be formed with more plies thanthe male part to provide a reinforced Interlock. These reinforcements provide a muchstronger package lock which better prevents the packages from Inadvertent opening.When incorporated, the V-notches provide further resistance to opening of theinterlock, and the hinges provide the ability to control the shape of the packageopening. Accordingly, it is a primary object of the invention to provide novel reinforcedopenable and resealable interlocking closures for packages.

Another object of the Invention is to provide packages having novel reinforcedopenable and resealable Interlocking closures which may be provided at intervalsalong their lengths with hinge structures which separate the interlocking closures Intosegments and control the shape of the package opening. A further object of the invention is to provide a package having a novelreinforced openable and resealable interlocking closure which may be provided atintervals along its length with V-notch reinforcements.

An additional object of the invention is to provide a package having a novelreinforced openable and resealable interlocking closure as aforesaid in which thereinforcement is partly provided by selectably added layers of the packaging or otherfilm.

Yet another object of the Invention is to provide packages having novelreinforced openable and resealable interlocking closures as aforesaid in some of which 3 the closure is formed transversely to the direction of packaging film flow and in othersof which the closure is formed in line with the direction of packaging film flow duringthe packaging operation running at line speed. A yet further object of the invention is to provide novel packages as aforesaid inwhich the reinforced resealable interlocking closure is integrally formed from layeredtogether contiguous portions of the packaging film during the packaging process anddoes not require that additional materials be added to the packaging film to form theresealable closure, and in another form the resealable interlocking closure is formed ina heat sealable strip heat sealed to the packaging film. A still further object of the invention is to provide novel packages as aforesaid inwhich the packages may be formed from a variety of packaging films such aspolypropylene, polyester, polyvinyl chloride, high and medium density polyethylene,and various film laminations.

Still another object of the invention is to provide novel packages as aforesaid inwhich the reinforced resealable interlocking closure is integrally formed from thepackaging film by reversely fanfolding the packaging film either across or orthogonal toits width to form a stack, sealing together the reversely folded stack in plane with thefilm, and thermoforming the sealed stack into the resealable locking feature. A further object of the invention is to provide a package having a novelreinforced openable and resealable interlocking closure in which the resealable closureextends only partly across the package to limit the open size of the closure.

An additional object of the invention is to provide novel methods and apparatusfor making packages according to the invention.

The foregoing and other objects of the invention will be more clearly understoodfrom a reading of the following description in conjunction with an examination of theappended drawings, wherein:-

Figure 1 is an isometric view of a package according to the invention showingshowing the longitudinally extending package seal uppermost, the package end seals,the integrally formed reclosable locking feature with the reinforced female portionuppermost, and the hinges and V-notch reinforcements;

Figure 1A is a digrammatic end view of an open package tube before end sealingshowing the longitudinally extending package seal as a conventional single overlaptype as seen in Figure 1;

Figure IB is a digrammatic end view of an open package tube before endsealing showing the longitudinally extending package seal as a conventional doubleoverlap type; 4

Figure 2 is an enlarged cross sectional view through the resealable closure andend seal as would be seen when viewed off the package center along the line 2-2 onFigure 1, showing both the male and female portions as formed of three plies of thepackaging film and corresponding to the longitudinal seal package type of Figure 1A;

Figure 3 is an enlarged cross sectional view through the resealable closure andpackage end seal as would be seen when viewed centrally of the package along the line 3-3 on Figure 1, showing the male portion formed of three plies of the packaging filmand the reinforced female portion formed of six plies of the packaging film, also ascorresponding to the longitudinal seal package type of Figure 1A;

Figure 3A is an enlarged cross sectional view through the resealable closureand package end seal as would be seen when viewed centrally of the package along theline 3-3 on Figure 1 If the package longitudinal seal were as shown in Figure IB,showing the male portion as formed of three plies of the packaging film and thereinforced female portion as formed of nine plies of the packaging film;

Figures 4 and 5 respectively show the tearing off of the package endseal and theopening of the resealable closure of a package as shown in Figure 1 with the packageopening shape being octagonalized by the action of the hinge formations;

Figure 5A is an enlarged fragmentary view through the portion of the reclosableseal in the phantom circle on Figure 5 showing the hinge formations and V-notchreinforcements;

Figure 6 is a diagrammatic Illustration of apparatus for and method offormation of packages according to the invention, showing the stages of package andclosure forming from the packaging film during the packaging process;

Figure 7 is an isometric view of the portion of the apparatus whichaccomplishes the fanfolding of the film; * Figures 8A through 8E are cross sectional views through the apparatus ofFigure 7 showing the stages of formation of a fanfolded and sealed film stack:

Figure 8F is an enlarged fragmentary view through the portion of the sealedstack shown in the phantom circle on Figure 8E;

Figure 9 is a cross sectional view through the package end sealing and closureforming device for the reinforced resealable locking closure feature, the hingeformations and V-notches being formed at the same time when desired;

Figure 10 is an end view of the film scouring wheels seen in Figure 6 before thewrapping station;

Figure 11 is a plan view of an alternative form of package according to theinvention showing the package end seals and an arcuate Integrally formed resealable 5

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locking feature according to the invention.

Figure 12 is a digrammatic fragmentary end view of the longitudinally extendingpackage seal of an open package tube before end sealing, shown as a single overlaptype of the kind seen in Figure IA, except also showing an additional longitudinallyextending strip sandwiched between the overlapped margins of the packaging filmweb;

Figure 12A is an enlarged cross sectional view through the resealable closureand package end seal as would be seen when viewed centrally of a package along aline such as 3-3 on Figure 1 if the package longitudinal seal were as shown in Figure12, showing the male portion as formed of three plies of the packaging film and thereinforced female portion as formed of six plies of the packaging film with the addedcentral ply;

Figure 12B is a diagrammatic showing of a typical apparatus for overlaying afilm strip onto a web;

Figure 13 is an isometric view of a package according to the invention showinga longitudinally extending reinforced reclosable side edge package seal;

Figure 14 is a diagrammatic line drawing view through the package of Figure 13as would be seen when viewed along line 14-14 on Figure 13 except that thelongitudinal package seal is shown as a single overlap type instead of a double overlaptype;

Figure 15 is an enlarged cross sectional view through the resealable closure aswould be seen when viewed along the line 15-15 on Figure 13, showing the male partas formed of three plies of the packaging film and the female part as formed of fiveplies of the packaging film;

Figure 16 is a diagrammatic illustration of apparatus for and method offormation of packages according to the invention of the type shown in Figure 13,showing the stages of package forming and closure from the packaging film during thepackaging process;

Figure 17 is a cross sectional view through the fanfolder apparatti for formingthe fanfolded stacks of packaging film from which the male and female parts of theinterlocking resealable closure of Figure 13 are formed, as would be seen when viewedalong line 17-17 on Figure 16;

Figure 18 is a cross sectional view through the heated dies which form themale and female parts of the resealable closure shown in Figures 13 and 15, thisshowing being also applicable to the following cooling devices which set the formedparts, and the insulator blocks therebetween, as would be seen when viewed along line 6 18-18 on Figure 16;

Figure 19 shows an interlock closer for interlocking the formed parts of theclosure prior to package formation;

Figure 20 shows apparatus for continuously forming bags with a resealableclosure of the type illustrated in Figure 13;

Figure 21 shows a package similar to that of Figure 1 except that the resealableclosure extends only partly across the package; and

Figure 22 is a diagrammatic showing of an apparatus for overlaying a film striponto a web transversely to the direction of movement of the web to form a strip ofstacked film as an alternative to a fanfolded stack.

Figures 22A and 22B are isometric enlargements of the sealing bars part of theapparatus of Figure 22 showing the web and film strip prior to and during a sealingoperation.

In the several figures, like elements are denoted by like reference characters,which to the extent possible are the same as the correspondingly placed referencecharacters in the earlier application.

Considering first Figures 1 and 11, there are seen packages 20 and 20’ havingat opposite ends heat sealed end seals 21A/21B and 2ΓΑ/2ΓΒ, tearoff feature 62,and resealable package locking closures 22 and 22’. The packages are identical exceptfor the shape of the resealable locking closures, closure 22 in Figure 1 being formedalong a straight line, while closure 22’ in Figure 11 is formed along an arc. Thestraight line form of closure requires less package length than the arcuate form, butthe arcuate form provides somewhat easier package opening because the opening forceis effectively applied to a shorter length of the closure. Both types are formed in thesame way, as will be subsequently shown. The closures 22 and 22’ may also haveformed into their structures at intervals along their length, hinge formations 31and/or reinforcing V-notches 60. Figure 1 is shown with the longitudinal packageseal, which is normally the bottom surface of the package, shown uppermost to revealdetails of the resealable closure 22.

The single overlap type of longitudinal seal as seen in Figure 1 is shown indiagrammatic end view in Figure 1A as an open package tube before end sealing,showing the overlapped outer and inner margins 48 and 49 of the package bottomsurface 23, and the continuous package upper surface 24. An enlarged cross sectionof this closure structure not taken through the overlap is shown in Figure 2, while a 7 cross section of the closure structure taken through the single overlap is shown inFigure 3. A cross section of the closure structure as would be seen when takenthrough the double overlap longitudinal package seal structure showndiagrammatically in Figure IB as having an outer layer 48, a middle layer 50 and aninner layer 51, is shown in Figure 3A. All of these closures are Illustratively shown asformed of single or multiple thermally fused triple plies or layers of packaging film, theformation of such triple plies into a strip 30 being described hereinafter. As will besubsequently shown, the resealable closures are formed during the package makingprocess from multiple reversely fanfolded layers of the film from which the packagesare made, as best seen in the enlarged cross-sectional views of Figures 2, 3 and 3A towhich attention should be now directed.

The Intemested closure sections of all of Figures 2, 3 and 3A are seen to beformed in an arrowhead shape with the lower legs of the arrowhead angled inwardlydownward toward one another. This angled orientation of the base legs results ineasier package opening and reclosing. In Figure 2 the upper film portion 23 of thepackage 20 is seen reversely folded into three thermally fused layers 23A/23B/23Cforming the outer female section 22A of the closure 22, with the lower film portion 24being similarly folded into three thermally fused layers 24A/24B/24C forming theinner male section 22B of the closure 22. This structure is the cross section throughthe interlocking closure taken at any point that is not through the longitudinalpackage seals shown In Figure 1A as 48/49 and in Figure IB as 48/50/51, and is thesame for all of the packages. It is identical to the structure of Figure 2 of my earlierapplication and functions in the same way. The package overlap structures of Figures3 and 3A however depart materially from that of Figure 2 as will be now described.

Considering first the single overlap structure of Figure 3, it is seen that theinner male closure portion 22B is the same as that of Figure 2, consisting of threelayers of packaging film 24A/24B/24C, but that the outer female portion 22A insteadof also having only three layers has six thermally fused layers in the overlap region ofmargins 48/49, namely, layers 48A/48B/48C/49A/49B/49C. This renders thefemale closure portion 22A substantially stiffer in this overlap region located centrallyof the package, and provides increased holding power of the male closure portion 22Bwithin the female portion 22A at the maximum opening stress region of the package.In the double overlap structure of Figure 3A it is seen that the inner male closureportion 22B Is also the same as that of Figure 2, consisting of three layers ofpackaging film 24A/24B/24C, but that the outer female portion 22A instead of alsohaving only three layers has nine thermally fused layers in the overlap region of 8 margin a 48/50/51, namely, the layers 48A/48B/48C/50A/50B/50C/51A/51B/51C.This renders female closure portion 22A even stlffer in this overlap region than thestructure of Figure 3.

Figures 4 and 5 illustrate the opening of the package 20 by first tearing off theend seal 21B adjacent to the closure 22, as shown in Figure 4, by means of the tearofffeature 62 shown in Figure 1, and then opening the resealable locking closure 22 byseparating the outer and inner sections 22A and 22B as shown in Figure 5. Theseparation process, for those interested, is illustrated In Figures 5 and 6 of my earlierapplication and show the outer and inner sections 22a and 22b, corresponding to 22Aand 22B of the present application, being respectively expanded and compressed asthe inner section 22b is pulled out of the outer section 22a, and then shown springingback to their static state conditions. The process is identical for the resealable closureof the present application and the drawings are not here repeated. Figure 5 alsoillustrates the action of the hinge formations 31 which permit the stiff interlock seal22 to flex about the hinges 31 and form, in the package shown, a generally octagonalopening that renders access to the package Interior much easier. Fewer or morehinges 31 may of course be used depending on the package opening size and thenature of the contents. The reinforcing V-notches 60 stiffen the sections of theresealable closure disposed between the hinges 31. The hinges 31 and V-notches 60are seen more clearly in the enlarged fragmentary showing of Figure 5A.

Figure 6 is a diagrammatic showing of apparatus for producing finishedpackages as shown in the Figures. Film 25 from a roll 26 of heat sealable packagingfilm is spooled off and fed around roller 27 and between rollers 28 to the filmfanfolding device 29 where at package length intervals the film is multiple folded andedge heat sealed into strips 30 extending fully widthwise of the running film with thestrip layers 30 being unsecured to one another between the edge seals. For thestraight seal of Figure 1 the strip width is approximately one half inch, while for thearcuate form of Figure 11 It could be about one inch. To accomplish this the film 25 iseither made of thermoplastic material or is thermoplastically coated. The fanfoldingdevice 29 and the process of forming the film 25 to include the heat sealed fanfoldedstrip 30 are shown in detail in Figures 7 and 8, the position of the apparatus of Figure7 being that shown in the operating cycle position of Figure 8C.

The device 29 consists of, a pair of fanfolding plates 37 having window slots 38,the plates being synchronously shiftable toward and away from one another in slightlyseparated parallel planes, upper and lower film clamping guide rods 39, and upperand lower heating bars 40A and 40 B carried on the guide bars 39. The upper heating 9 bar 40A is provided along its lower face with a centrally longitudinally extending slot35 which forms a pair of downturned legs 52 extending wldthwise of the runninglength of the film, while the lower heating bar 40B is provided along Its upper facewith a similar centrally longitudinally extending slot 35 which forms a pair ofupturned legs 52, the downturned and upturned pairs of legs 52 being positioned inapposed relationship. The film 25 moves from right to left between the plates 37 asshown by arrows 41 in Figure 8A. As shown in Figure 8B by the arrows 42, the plates37 are shifted toward one another into overlapping position to form a three layerfanfold of film 25 with the windows 38 of the plates 37 vertically aligned. Next, asshown in Figure 7 and in Figure 8C by the arrows 43, the film clamping guide rods areshifted toward one another through the windows 38 to clamp the three layers of filmtogether.

As shown in Figure 8D by arrows 44, the plates 37 are then retracted awayfrom one another, while as shown by arrows 45 the heating bars 40A and 40B areshifted toward one another so that the upper and lower pairs of legs 52 of the heatingbars engage the upper and lower outer surfaces of the fanfolded film strip to edge sealthe layers together into the heat sealed strip 30 with the layers of strip 30 beingunsecured to one another between the edge seals 53 as best seen In Figure 8F. Theunsecured condition of the layers of strip 30 shortens the time required tosubsequently form the interlocking closure because the layers conform to the formingdies more easily and do not have to be first resoftened to be formed. Finally, asshown by arrows 46 in Figure 8E, the rods 39 and heating bars 40A and 40B areretracted, and the strip 30 moves out of the fanfolding device on its way to thepackaging device 33. It should be understood that during the course of formation ofthe strip 30 the entire apparatus 29 moves in the direction of motion of the film 25and then retracts to its initial position in preparation for the next cycle of stripformation, as shown by the arrow 47.

These strips 30 then proceed to a device for removing the thermoplastic coatingfrom most of the undersurface of the strip, shown illustratively as an abradergenerally designated as 63. Other known types of devices are also usable for thispurpose, such as corona devices. As seen in Figures 6 and 10 the abrader 63 includesa pair of abrading wheels 64 driven by motors 65 supported on a carrier bar 66. Thecarrier bar 66 reciprocates transversely to the running length of the film to treat theundersurface of the strip 30 which will form the non-sealable facing surfaces of theinterlocking closure, as shown by arrow 67, and also moves longitudinally with thefilm, as shown by arrow 68, for a distance sufficient to complete abrasion of the 10 desired portion of the strip. In the case of a single overlap package as showndiagrammatic ally in Figure 1A, the longitudinal film margin which forms the portion48 is left with its thermoplastic surface intact so that it can subsequently be heatsealed to the opposite film margin 49 during package formation by packaging machine33. This also is the case for the margin 48 of the double overlap package as showndiagrammatically in Figure IB, and for the opposite longitudinally extending filmmargin which forms the interface between layers 50 and 51. In this latter case, it anabrader is utilized, only one abrading wheel would be used.

Upon completion of a strip treatment the abrader moves downward out ofengagement with the film strip 30 and returns to its starting place to engage the nextstrip. The film then passes around the rollers 32 and into the packaging machine 33where the items 34 to be packaged, carried on conveyor 36, are wrapped and emergefor end sealing and package cutting by the device designated generally as 69, andformation of the resealable interlocking closure by the device designated generally as70, being thereafter carried away for packing for shipment by the conveyor 36.

The completion of the packaging by end sealing and reclosable seal formationtakes place respectively at the sealing station sealing device 69 and forming device 70shown in Figure 6 and in the enlarged cross sectional detail of Figure 9, to both ofwhich reference should now be made. After emerging from the package formingapparatus 33 the package ends are sealed by the sealing device 69, and at the sametime the package resealable locking feature is completed from the strip 30 by a closureformer 70. A wrapped product carrying a strip 30 and shown as 71 emerges from thepackaging machine 33 and passes to a position between the sealing device 69 and theclosure former 70. The upper and lower heat sealing bars 72 and 73 move toward oneanother to heat seal the ends of adjacent packages to form the opposite end seals 21Aand 2IB shown in Figures 1 and 11, followed closely by the descent of the cutting bar74 which severs the seals 21A/21B of the adjacent packages from one another.Moreover, the apposed faces of strip 30 are held in proper position for closure formingat former 70 by the immediately adjacent heat seal 2IB.

As seen in Figure 6, the strips 30 have been wrapped during packaging so thateach strip is disposed in two layers, one above the other with the abraded surfaces incontact, but remain unsecured to one another so that they may be subsequentlyseparated. As seen in Figure 9 the closure former 70 consists of an anvil die 54formed at the lower end of the upper heater block 55, a lower recess die 56 formed atthe upper end of lower heater block 57, a pair of apposed reciprocable forming plates58, vacuum ports 59 in the lower heater block 57. and heaters 61 in the upper and 11 lower heater blocks. The anvil die 54 and recess die 56 are shown as configured toproduce the upper end of the arrowhead interlock shape, but also formedlongitudinally along these dies are the proper configurations to form the hinges 31and/or the reinforcing V-notches 6.0. "when it Is desired to include them in the interlockclosure.

In one method of forming the resealable closure, as the edge sealed strip 30comes into position between the upper and lower heater blocks 55 and 57 of theforming device 70, the latter move vertically toward one another, and the formingsequence is initiated by moving the heated upper anvil 54 and lower recess 56 intomating position and heat forming the strip 30 into the recess 56 where the strip isretained in position by vacuum drawn through the manifolds 59. The anvil 54 thenretracts while the vacuum continues to hold the strip in the recess 56. The formingplates 58 then move toward one another and shape the inturned lower legs of thearrowhead shape into the heat softened strip 30. Finally, the forming plates 58 areretracted and the vacuum is released, thereby releasing the formed resealable closure.The forming device is then retracted to its starting position in preparation for formingthe next closure. This sequence repeats and produces a continuous line of packagedproducts.

In a second, and preferred method of forming the resealable closure, as the edgesealed strip 30 comes into position between the upper and lower heater blocks 55 and 57 of the forming device 70, the latter move vertically toward one another, and theforming sequence is initiated by moving the heated upper anvil 54 and lower recess 56into mating position and heat forming the strip 30 into the recess 56. Next, theforming plates 58 then move toward one another and press the upper sides of the strip30 against the sides of the upper heater block male die 55. The upper heater blockand male die 55 are then retracted, and the forming plates 58 are moved furtherinward to pinch together the portion of the strip 30 therebetween and form thearrowhead shape in the interfitted parts of the resealable closure. Then, the lowerheater block and female die 56 are moved further upward toward the forming plates 58 to move the rear surfaces of the arrowhead into a more planer alignment, renderingthe arrowhead more triangular in shape and more similar to the showing of Figure 2aof parent application S.N.08/861,576. The forming plates 58 are then retracted totheir starting position in preparation for forming the next closure. This formingmethod does not require the use of vacuum, and dispenses with the need for that typeof apparatus.

Considering now the embodiments of the invention which are formed by edge 12 folding the film web 25 or adding a film strip to Increase the number of layers of thelongitudinally extending package seal, consider first the edge folding form of makingthe package. If film web 25 Is longitudinally single folded along one edge beforeentering the fanfold device 29, the single overlap packaging apparatus which producesa longitudinal package seal as shown in Figure 1A. will produce an interlock 22 asseen in Figure 3A rather than as seen in Figure 3. This is because the fanfold device29 will make a six fold through the folded edge of strip 30. Devices for edge foldingrunning webs are well known in the art, and the edge fold width would be made aboutthe same as the width of the package longitudinal seal.

If instead of edge folding the running web 25, an additional strip 75 ofpackaging film, or other heat sealable film, is laid over one longitudinal margin of theweb 25 with the web edge and one strip edge substantially congruent, two differentstructures can be produced depending upon the point on the web where the overlay isintroduced. If the overlay of strip 75 is done before entry of the wTeb 25 into thefanfold device 29, then the same interlock closure structure results as previouslydescribed for edge folding the web, namely, the Interlock closure structure shown inFigure 3A. However, if the overlay of strip 75 is done after the strip 30 has beenformed, then the longitudinal package seal will appear as shown in the detail of Figure12, and a different interlock closure structure is formed, as shown in Figure 12A.Strip 75 is shown for illustrative purposes as about three times the thickness of thepackaging film 25, but can be of any thickness desired, as determined by theparticular application. Apparatus for applying a strip 75 to a web are well known inthe art, and typically could be as shown in Figure 12B in which are seen a film striproll 76, a pair of strip pulling rollers 77, and a pair of positioning rollers 78 which mayalso be heat sealing rollers applying the strip to the web 25. The strip 75 could alsobe a strip slit off of one longitudinally running edge of the web 25 just prior to overlayon the web.

Consider now the Isometric view of paickage 79 as seen in Figure 13, whichshows a longitudinally extending reinforced reclosable side edge package seal 80having an outer female part 80A and an inner male part 80B, the seal 80 being bestseen in the diagrammatic showing of Figure 14, and a rupturable seal 81 by means ofwhich the package edge margin 82 may be removed to open the package by providingaccess to the resealable closure 80. Figure 14 also discloses a single overlaplongitudinal package seal 83, which could also be a double overlap seal as a functionof the particular type of wrapping machine. Figure 15 shows an enlarged crosssectional view through resealable closure 80 as would be seen when viewed along line 13 15-15 on Figure 13, with the male part 80B formed of three plies 80B1/80B2/80B3 ofthe packaging film and the female part 80A as illustratively formed of five plies80A1/80A2/80A3/80A4/80A5 of the packaging film. Apparatus for forming the seal80 and the package 79 is seen in Figure 16, to which reference should now be made.

In Figure 16 there is seen a web of packaging film 84 moving into the broad endof the fanfolding apparatus 85 and emerging from its narrow end as a narrowed webhaving formed therein the two stacks of folded film 86 and 87 which are immediatelyheat sealed by the heat seal rollers 90 into sealed strips which respectively will becomethe female part 80A and the male part 80B of the resealable interlocking closure. Asshown in Figure 17 the four fanfold guide plates 88 continuously form the five layerfemale stack 86, and the two fanfold guide plates 89 continuously form the three layermale stack 87. The heat sealed stacks 86 and 87 then respectively enter the heatedfemale forming die 91 and heated male forming die 92 where the interlocking femaleand male parts 80A and 80B respectively are formed in the stacked strips 86 and 87,as best seen in the showing of Figure 18. If instead of a fanfolded stack it is desired toutilize a strip of heat sealable material to form the strips 86 and 87. the fanfoldingapparatus 85 may be replaced with a pair of strip appliers of the kind shown in Figure12B.

Upon emergence from the heated forming dies, the closure parts 80A and 80Bpass through thermal Insulating blocks 93 of the same cross section as the dies andinto the cooled setting dies 94 which quickly cool the parts to stable mechanicalconfigurations. Before the web enters into the packaging apparatus 96 the doubleperforation wheels 95 apply the tear-off perforation lines 81 to the web. The packager96 wraps the product, forms the longitudinal package seal 83 best seen in Figure 14,and positions the closure parts 80A and 80B for closure, after which the latter arepressed together into Interlocking fit by the press rollers 97 and 98, as best seen inlarger detail in Figure 19. Successive incomplete packages of product are then endsealed and severed by package end sealer and cutter 99 to form indivudual finishedpackages 79.

An apparatus for making a continuous series of bags with resealableinterlocking closures, somewhat similar in concept to that of Figure 16, is shown inFigure 20 where there are seen a web 100 having the running longitudinal edges stackformed by the male and female stackers 101 and 102 into stacks 103 and 104, whichstacks are then edge sealed by heat seal rollers 105. The sealed stacks, as before,enter the heated forming dies 106 and 107 where the male and female interlocks 108and 109 are formed, and emerge from the cooled setting dies 110 and 111. The web 14 with the interlocks formed thereon is advanced by drive rollers 112 and 113, and theweb edge carrying the female interlock 109 is turned over the inverter bar 114 intoalignment with the male interlock 108, and the two are pressed into engagement by thepress rollers 115 and 116. The bags are completed by the side sealer 117 which heatseals the side edges of the bags and does one of two other things. One option is tomake a narrow edge seal and also sever successive bags from one another. Anotheroption is to make a wider fin seal with a line of severance formed midway between theedges of the seal and not to sever the bags, but to wind them on a roll or reverse foldthem into a stack for bulk packaging. If instead of a fanfolded stack it Is desired toutilize a strip of heat sealable material to form the strips 103 and 104, the fanfoldingdevices 101 and 102 may be replaced with a pair of strip appliers of the kind shown inFigure 12B.

An alternative form of package to that shown in Figure 1 is shown in Figure 21as 119, and can be produced by the same apparatus as shown in Figure 6 by amodification to the closure former dies 70. As seen in Figure 21 the package 119 hasmost of the same features as the package of Figure 1, namely, an end seal 120, a tear-of feature 121, and a resealable closure 122. However, the package of Figure 21differs from that of Figure 1 in that the resealable closure 122 extends only partlyacross the width of the package, the rest of the package in line with the closure 122being formed as a permanent heat seal 123. This form of package is useful when thepackage contents is a pourable material, such as cereal or rice, or the like, and it isdesirable to have the package open only partly for better pouring control. The relativelengths of the resealable closure 122 and permanent seal 123 can be proportioned asdesired by the configuration of the closure forming dies 70.

Considering finally Figures 22, 22A and 22B, there is shown an alternativeapparatus for forming the stacked edge-sealed strip from which the resealableinterlocking package closure Is formed transversely to the web. Instead of fanfoldingthe web of packaging film as previously shown and described, a stack is formed bysecuring a separate strip of substantially constant thickness material to the web ofpackaging film transversely to its running length rather than colinearly as shown inFigure 12B. Multiple strips can be so stacked or a single strip of whatever thicknessis desired. In Figure 22 there Is seen packaging film 124 spooling off of a roll 125 andpassing into and through a sealing device 126 where a piece 127 of a strip of flexiblematerial 128 which spools off of a roll 129 is heat sealed to the film 124 after beingsevered from the strip 128 by the knife and anvil 130. Stacked heat-sealed strips 131are produced at package length intervals by the apparatus to be now described. 15 16 A vacuum belt 132 draws the strip material from the supply roll 129 In themanner well known in the art and feeds it through the knife and anvil 130transversely across the upper surface of the web 124, the strip being picked up by thevacuum belt 133 and carried to a point approximately an Inch from the far edge 134of the web 124, the orie inch representing the spacing of the knife 130 from the nearedge 135 of the web 124. Next, the knife 130 severs the the piece 127 from the strip128:..and the vacuum belt 133 moves the ends of severed strip 127 the remaining inchinto congruency with the web edges 134 and 135. At this point in the cycle themovement of web 124 and the vacuum belts 132 and 133 are stopped, as seen inFigure 22A, and the severed piece 127 is heat sealed to the web 124. Heat sealing iseffected by the upper heat seal bars 136 and lower heat seal bars 137 which, as seenin Figure 22B, are moved respectively down and up to heat seal the edges of thestacked strip and web, as at 138. The sealer bars are then retracted, and movementof the web 124 and strip 128 resumes for the next cycle.

The surface of the strip 128 which is not sealed to the web 124 does not haveheat-sealable properties so that a surface abrading device such as is shown at 63 inFigure 6 is not needed. However, a patch of hot melt material Is applied to either theterminal upper inch of one or both ends of the strip 131 at a downstream station,depending upon the type of longitudinal seal that is to be formed.

Having now described the invention in connection with particularly illustratedembodiments thereof, it will be understood that modifications and variations of theinvention may now occur from time to time to those normally skilled in the art withoutdeparting from the essential scope or spirit of the Invention, and accordingly it isintended to claim the invention both broadly and specifically as indicated in theappended claims. 16