Modified sealing machine

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Patent issued

01/12/1993

Inventor(s):	Latter, Melvin R.
Application	No. 07/439,272 filed on 11/20/1989
Current US Class	53/557, 53/568, 493/929
Field of search	53/133, 53/373, 53/410, 53/412, 53/433, 53/442, 53/455, 53/459, 53/463, 53/477, 53/479, 53/511, 53/557, 53/562, 53/568, 53/128.1, 53/133.1, 156/515, 156/583.4, 156/583.8, 156/583.9, 493/194, 493/195, 493/206, 493/929
International Classes:	B65B 5110, B65B 906, B65B 5302
Examiners
Primary	Sipos John
Secondary	Johnson Linda B.
Attorney, agent or firm:	Ladas & Parry
US patent references	3016284, 3123955, 3390507, 3496700, 3516537, 3681890, 3912575, 4000029, 4175994, 4256024, 4512138, 4697401, 4905452
Foreign patents	974827 (10/31/1964, GB)

Disclosed herein is a modified L-sealer machine for use in wrappingproducts in plastic wrap. The machine cuts the wrap to form integrallytherein a tear tab. This is done by modifying the L-sealer bar to shapethe tab in the plastic wrap while sealing it around the product.
BACKGROUND OF THE INVENTION
The present invention relates to sealing machines for shrink wrapping andother type of packaging.
As known in the art, hand-fed and automated wrapping of items, and inparticular, shrink wrapping, involves the following process. Acenter-folded plastic sheet wrap is pulled from its roll over a separatorbar or plate to separate the wrap about the fold thereby providing a spacefor insertion of the product to be sealed by the wrap. The leading edge ofthe wrap, if not sealed together, is then sealed. If it is intended toultimately shrink the wrap around the product with hot air, holes are madein the wrap usually by the application of hot or cold punches prior to orafter pulling the wrap to the area in which the product to be packaged isinserted. The product is then inserted into the wrap, that is, betweenboth sides of the wrap defined by the fold, and the product and wrap arethen pulled to a sealing area. Here a sealer frame shaped like a reverse Lis pulled down onto the wrap around the product. The sealer frame isdesigned to carry heat so that when it is lowered and pressed onto thewrap around the product, it seals both sides of the wrap together in thearea where the sealer bar is present, thereby sealing the product in thespace within the wrap. When the sealer frame touches the wrap, it softensand bonds or laminates together the two sides of the wrap both under andnear the frame. If the frame is left on the wrap for an adequate period oftime, the heated plastic wrap under the frame melts away from theremaining wrap so that when the reverse-L sealer frame is lifted, theproduct and its surrounding wrap stand independent of the remainder of thewrap and may be readily moved to the hot air shrinking area. The edge ofthe remaining portion of the wrap is sealed from the heat generated fromthe sides of the reverse-L sealer frame. Thus, when the reverse-L sealerframe is again brought down for the next product, the next product isfully sealed on all sides.
In the shrink-wrapping process, the sealed product is transferred to anarea in which hot air is applied to shrink the wrap tightly around theproduct. The holes in the wrap formed earlier by the hot or cold punchesallow the air trapped between the wrap and the product to escape so thatthe wrap shrinks to the size of the product contained within its boundswithout an air pocket being formed therebetween. During such shrinkingprocess, the hot or cold formed holes do not seal closed.
One disadvantage of the foregoing wrapping method is that it provides nomeans for removal of the product once the wrapped product has reached itsultimate consumer. The user is left to use outside cutting means to severthe wrap to release the product. At times, this can result in the userinadvertently damaging the product in the process of cutting away thewrap.
A second disadvantage is the requirement of the additional step of"venting" the wrap by punching holes therein should shrink wrapping bedesired.
A third disadvantage is that the product is sealed on all four sides whenit may be desired that one side be left open.
Known sealing devices are disclosed in U.S. Pat. No. 4,697,401 to Kessler,U.S. Pat. No. 3,123,955 to Weissensee, U.S. Pat. No. 4,512,138 toGreenawalt, and U.S. Pat. No. 3,681,890 to Pringle.
U.S. Pat. No. 3,681,890 to Pringle addresses the first disadvantage notedherein by disclosing a machine in which a tear tab is heat-sealed to theseam of each wrap for tearing open the wrap to get to the enclosedproduct. However, the tear tab disclosed by Pringle requires the additionof an extra step to the sealing process, that of attaching a tear tab.Further, the tear tab is not fail proof. If it is not properly sealed tothe wrap, it may rip free of the wrap without creating an opening in thewrap to reach the inside product This is particularly likely with thePringle method since the tear tab is attached to a seam area, one of thestronger areas of the wrap and thus one of the areas least likely to rip.
Kessler in U.S. Pat. No. 3,123,955 and Weissensee in U.S. Pat. No.3,123,955 address the issue of maintaining one open edge of the productbut do so by adding the step of cutting that edge open after the producthas been sealed within the plastic wrap.
The present invention discloses a tear tab that is integral with thesealing wrap rather than merely attached to the wrap. Therefore, it is atab that will not rip away from the wrap without ripping the wrap too. Itdoes this without adding an additional step to the packaging process.
The invention also discloses a method of providing venting whileeliminating the step of using hot and cold punches.
Finally, it discloses a means of packaging a product in a wrap whileleaving one side of the wrap unsealed and therefore open to enable removalof the product. It does this without adding a cutting or other additionalstep to the known packaging process.
SUMMARY OF THE INVENTION
Disclosed herein is a method of sealing a product within two sides ofplastic wrap comprising the steps of
pulling a two sided wrap from a roll so that on one side of the wrap anopen base is defined by the two sides;
placing a product into said wrap by inserting it between said two sides;
bringing a heat sealer bar against the wrap and around at least a portionof said product, said bar sealing the wrap around said product except at atabbed area, said tabbed area defined by said bar and extending away fromsaid product to said open base such that said tab is open.

We claim:
1. A sealing machine for sealing plastic wrap around products insertedbetween two sides of said plastic wrap, said sealing machine beingcomprised of:
a heat carrying bar means comprising two bars, each having two ends, oneend of each bar extending in a first area to define at least a portion ofthe perimeter of a tear tab, the other bar ends defining the perimeter ofa space in a second area, said one end of one of said bars extending at anangle away from and projecting from said second area to form anon-arcuate, abrupt angle with the remainder of said one bar, said one endof the other bar forming a linear continuation of the remainder of saidother bar at said second area, said angle forming a tearing means, saidbar means being arranged such that said tear tab, said first area, andsaid second area are integrally connected to each other, such that whensaid bar means is placed on said plastic wrap and around said product,said product lies in said space in said second area, said bar means beingcomprised of a single portion which both severs to seal the plastic lyingthereunder so that the area of the plastic where said single portion wasplaced is melted together and severed from the remaining area of saidplastic wrap, wherein upon tearing at said tab, said tab will rip awayfrom said second area at the angle formed between said tab and said secondarea to enable one to access the products sealed in said second area.
2. The sealing machine of claim 1 wherein said bar mean is comprised of afirst bar and a second bar, said first bar being straight in shape andsaid second bar being L shaped so that the foot of said L extends parallelto said first bar to form said first area.
3. The sealing machine of claim 2 wherein said first and second bars aremounted on a common base.
4. A sealing machine for sealing plastic wrap around products insertedbetween two sides of said plastic wrap, said sealing machine beingcomprised of a heat carrying first bar and a heat carrying second bar,said bars defining at least a portion of the outside perimeter of a tab ina first area and defining the perimeter of a space in a second area, saidfirst area being integrally connected to said second area such that whensaid bars are placed on said plastic wrap and around said product, saidproduct lies in said space in said second area, said tab extending fromsaid second area, each of said bars acting to sever and melt the plasticlying thereunder to define the sealed edges of said second area and saidtab, said first bar being comprised of three portions, a first portionextending in one direction; a second portion connected to said firstportion and forming a right angle therewith; a third portion connected tosaid second portion and forming a right angle therewith; and wherein saidsecond bar is L shaped, the foot of said L being located opposite andparallel to said third portion to form said first area.
5. The sealing machine of claim 1 further comprising at least oneadditional bar, said additional bar being connected on a common base withsaid bar means and being used to form at least one additional tab, saidadditional tab extending away from said second space.
6. The sealing machine of claim 1 further comprising an additional barlocated parallel to one of said ends in at least said first area, saidadditional bar and said bar means being connected on a common base, saidadditional bar carrying less heat than said bar means and thereby actingonly to melt the plastic thereunder but not to sever it.
7. A sealing machine for sealing plastic wrap around products insertedbetween two sides of said plastic wrap, said sealing machine beingcomprised of:
a heat carrying bar means comprising two bars, each having two ends, oneend of each bar extending near one another in a first area to define atleast a portion of the perimeter of a tab, the other bar ends defining theperimeter of a space in a second area, said one end of one of said barsextending at an angle away from and projecting from said second area toform a non-arcuate, abrupt angle with the remainder of said one bar, saidone end of the other bar forming a linear continuation of the remainder ofsaid other bar at said second area, said bar means being arranged suchthat said tab, said first area, and said second area are integrallyconnected to each other, said tab extending from said second area;
a second bar connected in common with said bar means and located near saidends in at least said tab area, said second bar having a serrated edge,such that when said bar means is placed on said plastic wrap and aroundsaid product, said product lies in said space in said second area, saidbar means having a single portion which both severs and melts to seal theplastic lying thereunder so that the area of the plastic where said singleportion was placed is melted together and severed from the remaining areaof said plastic wrap, said second bar melting a plurality of spacedopenings in said plastic thereby forming perforations in at least saidtab, said perforations enabling said tab to be ripped along saidperforations to access the product in said second area.
8. A sealing machine for sealing plastic wrap around products insertedbetween two sides of said plastic wrap, said sealing machine beingcomprised of:
a heat carrying bar having two ends and a main portion connected to saidtwo ends, said two ends extending and projecting away from said mainportion to define a first area, one of said ends being at an angle withrespect to said main portion and forming a non-arcuate, abrupt angletherewith, the other of said ends forming a linear continuation of themain portion said angle forming a tearing means, said main portiondefining the perimeter of a space in a second area, said second area andsaid first area being integrally connected to each other such that whensaid bar is placed on said plastic wrap and around said product insertedbetween said two sides of said plastic wrap, said product lies in saidspace and said first area defines a tab of plastic extending away andprojecting at said angle from said second area to form said tearing means,said bar comprising a single means to sever and melt to seal the plasticlying thereunder, wherein upon tearing at said tab, said tab will rip awayfrom said second area at said angle between said second area and saidfirst area to enable one to access the product sealed in said second area.
9. The sealing machine of claim 1 wherein said ends of said bar extend atleast to the edge of at least one of said sides of said plastic wrap sothat said tab formed in said plastic wrap by said ends is open at an end.
10. The sealing machine of claim 1 wherein a piece extends from said barmeans into said tab to create a slit in said tab.
11. The sealing machine of claim 8 wherein said ends of said bar extend atleast to the edge of at least one of said sides of said plastic wrap sothat said tab formed in said plastic wrap by said ends is open at an end.

BRIEF DESCRIPTION OF THE DRAWINGS
The drawings below merely illustrate the invention. They are notnecessarily drawn to scale.
FIG. 1 is a perspective view of a typical prior art reverse-L sealer frameusing a center-folded roll of wrap.
FIGS. 2 through 4, 5a and 5b are simplified and diagrammatic views of thedevice of FIG. 1 showing the operating procedure thereof.
FIG. 6 is a perspective view of a first embodiment of the sealer frame ofthe invention.
FIGS. 7a, 7b, and 7c are diagrammatic views of the sealer frame of thepresent invention.
FIG. 7d is a product that has been sealed and the surrounding wrap hot-airshrunk.
FIGS. 8a, and 8b are diagrammatic views of the sealer frame of FIG. 7 asmodified to include the use of another sealer bar which carries less heatthan the bars of the main sealer frame and the use of a cutting extension.
FIG. 9a is a modification of the additional sealer bar of FIG. 8a.
FIG. 9b shows the wrapped package resulting from the use of the framedisclosed in FIG. 9a.
FIGS. 10a and 10b are diagrammatic views of a further embodiment of thepresent invention and a product wrapped with this embodiment.
FIGS. 11 and 12 show diagrammatically another embodiment of the presentinvention making use of a flat film wrapping mechanism.
FIG. 13 shows diagrammatically another embodiment of the present invention.
FIGS. 14 through 17 show diagrammatically a last embodiment of the presentinvention.
FIG. 18 shows one suggested embodiment of the present invention in whichtwo tabs are formed.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now in greater detail to the drawings, the prior art device isdisclosed in perspective and diagrammatically in FIGS. 1 through 5. Asseen in FIG. 1, conventional plastic film, bag-forming apparatus feed acenter-folded shrink plastic wrap or film 100 from a roll 98 over a plate96 (a bar may be used instead) to separate the wrap or film 100 therebydefining a space in which the product can be inserted. Wrap 100 iscomprised of centerfold 102, sides 106 and 108, open base 103 and leadingedge 101. Hot or cold punching means (not shown) are used in the areashown as 94 to vent the wrap 100 for later shrink wrapping. If the leadingedge 101 of wrap 100 is not already sealed (which it will not generally beif a new roll 98 of wrap 100 is being used), reverse-L sealer frame 110will be brought down on wrap 100 near leading edge 101 before insertingthe first item to be packaged. Frame 110 is comprised of bars 110a and110b, which are connected at right angles to each other in the shape of areverse L. Bar 110 a lies parallel to leading edge 101 of the film and isused to initially seal that edge. As noted above, the reverse-L sealerframe 110 is heated so that when bar 110a is brought against the plasticwrap 100 near edge 101, it will melt and sever the wrap directly under thebar and seal or laminate the wrap 100 around the edges of the bar.Therefore, by bringing frame 110 and the bar 110a against wrap 100 nearedge 101, bar 110a will form a new edge 101 under the area where bar 110aof frame 110 was placed and a sealed portion 92 next to that edge 101. Theframe 110 is then lifted, and the product 104 to be packaged is insertedin wrap 100 near sealed 92 edge 101. Product and surrounding wrap are thenpulled fully into the sealing station 90 and reverse-L sealer frame 110 isbrought down around the product to fully seal it within wrap 100 asdescribed below.
When frame 110 is lifted, the product and its surrounding wrap stand freeof the remaining wrap 100 since the frame has acted to sever the wrap aswell as seal it in the areas of severance. Package and wrap may then bemoved into the hot air shrinking area 88 to shrink the wrap whichsurrounds product 104 around product 104. Instead of a hot-air shrinkingarea per se being used, the product and wrap may be manually removed and aheat gun, which blows hot air, may be used to shrink the film 100 aboutthe product 104.
The foregoing process is illustrated diagrammatically in FIGS. 2 through 5.The center fold 102 of the wrap 100 divides wrap 100 into two sides 106and 108 thereby creating a two-layered base having an open end 103 whichlies opposite the center fold 102. The leading edge 101 of the wrap 100 issealed ab initio at 92 as discussed above and thereafter, each succeedingleading edge 101 is sealed from the sealing of a preceding product. Alsoas noted above, wrap 100 may be pierced to provide vent openings prior toinserting the product 104 between sides 106 and 108.
Product 104 is inserted through open base 103, into wrap 100, between sides106 and 108, near presealed 92 leading edge 101 and center fold 102. Theframe 110 is then brought down against wrap 100 and around product 104 toseal product 104 within wrap 100. Since the frame 110 is heated, uponcontacting the wrap 100, it pushes sides 106 and 108 against one anotherand melts or laminates them together and away from the main body of wrap100. Thus product 104 is fully sealed into wrap 100 by presealed leadingedge 101, center fold 102, and the newly sealed 92 edges defining theshape of frame 110. Upon removal of frame 110, product and wrap standindependent of the main wrap 100 due to the melting and severing of wrap100 directly under bars 110a and 110b as discussed above.
As noted above, the melting or laminating process caused by frame 110 onwrap 100 occurs to some degree around the periphery of frame 110 as wellas directly thereunder. Thus when product 104 and its surrounding wrap 100are free of the main portion of wrap 100 as shown in FIG. 3, there is lefta newly sealed 92 leading edge 101. As shown in FIG. 4, the foregoingprocess is repeated, a new product 104 being inserted between sides 106and 108 through base 103 near newly sealed 92 leading edge 101. FIGS. 5aand 5b, depict the entire process showing one product 104a in its sealedstate and a second product 104b being sealed into wrap 100.
After product 104 and its surrounding sealed wrap 100 are removed from thesealing area as shown in FIG. 5b, they are then passed to the hot airshrinking area 88 shown in FIG. 1, if shrinking of the wrap tightly aroundthe product 104 is desired. In the shrinking area, both product and wrapare subjected to a bath of hot air causing wrap 100 to "shrink" to a closefit around product 104, air trapped between product 104 and wrap 100 beingexpelled through the vent openings earlier discussed.
The product and its form-fit wrap are then ready for labelling or shipment.Of course, as noted above, the ultimate consumer must then remove the wrapfrom the product to access the product. Since no means of removal has beenprovided, the consumer is left to struggle with the opening of the wrapwhich struggle may result in the damage of product 104.
For the convenience of the ultimate consumer, the present inventiondiscloses a means of creating a wrap with an integral tear tab. This teartab also acts as a venting means so that puncturing of the outside wrap byhot or cold punches is unnecessary.
In FIG. 6, a first embodiment of the present invention, a modified sealingframe, is disclosed. The frame portion which will make contact with wrap100 is no longer a reverse L-shaped frame but a frame comprised of twoseparated bars. Even though these bars may ultimately be joined for easeof wiring by being mounted on a common base 86 as shown in FIG. 6, asshown in the diagrammatic views of FIG. 7a and 7b, the bars which willtouch wrap 100 will be seen on a planar level to be separated.
The first piece of the frame, bar 116, is merely a straight bar which liestransverse to the direction of advancement of the wrap 100 and product104. The second bar 118 is generally L-shaped so that one portion 118alies transverse to bar 116 and another portion 118b lies parallel to bar116. Thus, defined between portion 118b and bar 116 is a generallyrectangular space 120 which will produce an integral rip tab in the wrap100, as described below.
Wrap 100 does not need to be prepunched with vent openings. Instead, wrap100 is pulled from roll 98, passed over bar or plate 96 to separate sides106 and 108, and the product 104 is then inserted through open base 103near leading edge 101 (assuming it to have been presealed) and center fold102. Wrap and product are fed directly to the sealing station 90 which maybe a flat metal base onto which the bars 116, 118 of the present inventionmay be brought down against the wrap and around the product. Or the basemay be shaped like the bars as shown in FIG. 6.
When the frame is brought down against the wrap 100 and around product 104,the frame comprised of bars 116 and 118, bonds sides 106 and 108 togetheraround the periphery of product 104 by means of heat and pressure.However, as illustrated in FIGS. 7b and 7c, (which drawings are not toscale, the rip tab being exaggerated in size), the entire periphery is notbonded. Instead integral rip tab 121 is formed by the spaced relationshipof portion 118b and bar 116. The portion 118b and bar 116 extend at leastto and preferably beyond open base 103. In this way, rip tab 121 is leftopen at open base 103 to be used later as a vent opening 122 should shrinkwrapping be desired.
FIG. 7c shows a product wrapped with the present frame comprised of bars116, 118 after bars 116, 118 have been lifted away. The section of wrapwhich is defined in part by portions 118a and 118b and designatedgenerally with a "w" in FIG. 7b becomes waste and is discarded leaving anewly sealed edge 101 as described above. The product 104 sealed in itswrap 100 is severed by the heat from bars 116, 118 as described above,from the remaining portion of wrap 100 and is ready to be passed to thehot air shrinking station 88 where it is exposed to hot air to shrink thewrap around the product 104. Air caught between wrap 100 and product 104is expelled through opening 122.
Integral rip tab 121 is also shrunk although it will remain as an extensionfrom the product and wrap. In FIG. 7d, a perspective view of the wrap andproduct of FIG. 7c is shown after shrink wrapping, tab 121 clearlyextending outwardly of the wrap 100 which tightly surrounds product 104.
After the hot air shrinking step, the wrapped product is then ready for theconsumer who will be able to readily access the product by pullingintegral rip tab 121 to rip away wrap 100 from product 104. And, sinceintegral rip tab 121 is integral to wrap 100, it will not rip away fromwrap 100 without opening wrap 100 for removal of product 104.
FIGS. 8a and 8b, are a modification of FIGS. 7b and 7c. The frame beforecomprised of bars 116, 118 now consists of a third bar 115 which liesparallel to bar 116 and between bars 118 and 116 although it is placedmuch closer to bar 116 than 118. While bar 115 is shown narrower than bars116 and 118, it could be as wide or wider than these bars. Bar 115 is,however, designed to carry less heat than bars 116 and 118. As in thepreceding embodiment, while the wrap 100 will experience contact withthree separated bars, these bars may be ultimately joined in the fashionshown in FIG. 6 to facilitate the wiring and manufacture of these bars.The purpose of bar 115 is to create a second seam in the wrap thatsurrounds product 104. Because bar 115 carries less heat than bars 116 and118, bar 115 will not cause the portion of wrap 100 which it touches to besevered from the surrounding wrap 100 when bar 115 is placed against theplastic wrap 100 for the same length of time as bars 116 and 118. Onlybars 116 and 118 will do this. Bar 115 will only bind or laminate sides106 and 108 together to form a seam 113. Thus when the frame comprised ofbars 115, 116, 118 is lifted away from wrap 100, seam 113 will be presentas seen in FIG. 8b. This seam 113 will enhance rip tab 121 so that it isstronger and more likely to rip wrapping 100 along at least a portion ofthe length of seam 113, to ensure the creation of a larger opening in wrap100 when pulling rip tab 122.
Also shown in FIG. 8a (not necessarily drawn to scale) is a modification ofportion 118a. Here portion 118a extends beyond portion 118b toward bar 116to form an extension 119. Extension 119 will cause wrap 100 to meltthereunder creating slit 117 as shown in FIG. 8b (not necessarily drawn toscale). The presence of this slit will again facilitate the functioning ofrip tab 121. Although extension 119 is shown in combination with bar 115,the two need not be used in combination. Either one may be present alone.Further, extension 119 could just as well extend from portion 118b towardproduct 104 or extend diagonally from the corner joinder of portions 118aand 118b. That is, extension 119 would bisect the corner formed byportions 118a and 118b and extend toward bar 116. It could also extend inan angle from bar 116. Finally, bar 115 could be located more centrally ofbar 116 and 118b.
FIG. 9a is a perspective view showing a modification of bar 115. Here bar115a is serrated on its surface which will contact wrap 100 when bars 115,116, and 118 are brought against wrap 100. Here, also, bar 115 carries thesame amount of heat as bars 116, and 118. The serrations cause a pluralityof spaced holes to be melted into wrap 100 at each point where bar 115contacts wrap 100. Thus when the frame comprised of bars 115, 116, 118 islifted from wrap 100 and product 104, rip tab 121 and a portion of wrap100 will have defined therein a line of openings 121 as shown in FIG. 9b(not necessarily drawn to scale). These openings 123 are large enough sothat during the heat shrinking process they will not close. The openings123, create a perforated rip line or weakening for later opening the wrapby pulling rip tab 123 to rip away the wrap along these openings 121 fromproduct 104.
Shown in FIG. 10a is a further embodiment of the invention. Bar 118 is thesame shape as in the preceding figures. It is comprised of a first portion118a which extends parallel to the direction of feed of wrap 100 andproduct 104, and a second portion 118b which extends transversely to thedirection of feed of wrap 100 and product 104. This second portion 118bwould extend to, at least, the open base 103 of wrap 100. Bar 116 is nolonger a straight bar but forms two angles to define portions 116a, 116band 116c. First portion 116a extends transverse to the feeding directionof the shrink wrap 100 and parallel to portion 118b. Second portion 116bis connected to first portion 116a and extends generally parallel to thedirection of feed of wrap 100 and product 104. Third portion 116c connectsto second portion 116b and is generally parallel to first portion 116a.Third portion 116c define with portion 118b generally rectangular space120 so that integral rip tab 121 may be formed in wrap 100. Againpreferably, portion 118b and third portion 116c will extend at least toand/or beyond open base 103 of wrap 100 to leave integral rip tab 121 openat end 122 to vent air between product 104 and its surrounding wrap 100.Angled extensions 119 are also shown at the corners formed by bars 118aand 118b and bars 116b and 116c. The extensions and their angularplacement are optional. The bars of FIG. 10a are used in the same fashionas described for FIGS. 5 and 6. A product 104 wrapped with the aid of theframe comprised of bars 118 and 116 and extension 119 bar of FIG. 10a isshown in FIG. 10b. The product is again sealed in wrap 100 about itsperiphery except for integral rip tab 121 with its air vent opening 122formed from open base or 103.
As can be seen, the present invention permits various modifications of thesealer bars to form integrally with the wrap a rip tab which may act bothas a vent and a tab for opening the product. The invention may providecreating more than one rip tab, using extensions on bar 116 as well as onbar 118 to create slits 117 on both sides of rip tab 121, and variousother modifications.
One example of the present invention having two tabs is shown in FIG. 18.In this instance, an additional bar 18b may be seen to aid in the makingof both tabs.
In FIG. 11, a further modification is shown. This modification accommodatesthe use of flat or single wound film rather than a center-folded wrap. Inthis instance, there are two rolls (not shown) of flat or single woundfilm 100a, 100b, which are fed into the sealing station 90. Again, thereis no need to pierce this film as the present invention obviates the needof venting as a separate step. Product 104 is placed between the twolayers of film 100a, 100b, and the sealing bars 118, 116 are brought downagainst these two layers of film 100a, 100b, and around product 104.Because a flat film is being used in this instance, bar 116 has upperportion 116d which lies opposite open base 103 and is generally at a rightangle to and connected to transverse portion 116a. Upper portion 116dbinds wrap 100 around product 104 in the area where center fold 102 wouldhave been. Transverse portion 116a forms with second portion 118b againspaced area 120 to form integral rip tab 121 in film 100a, 100b.
FIG. 12 shows a product wrapped in the two pieces of film 100 with the useof the bars shown in FIG. 11. The product 104 is again sealed about itsperiphery with the exception of integral rip tab 121 and its vent opening122 formed by the extension of portions 116a and 118b to (and perhapsbeyond) open base 103.
FIG. 13 discloses an embodiment of the present invention in which the barsand extensions of any of the previous embodiments disclosed in FIGS. 5through 12 and 14 through 17 are shown. In this embodiment, prior toshrink wrapping film 100 and rip tab 121 around product 104, a furtherripping element 124 is inserted into tab 121 through open end 122. Thiselement might be a piece of material, thread, paper, cellophane, or anyother suitable product. This additional element 124 may be used to earmarkor further strengthen and facilitate the use of rip tab 121. The element124 may also carry a logo or be colored.
In FIGS. 14 through 17, a further embodiment of the present invention isdisclosed. In this embodiment, only sealer bar 116 is shown. This sealerelement is truly L-shaped.
In FIG. 14, the beginning of a new roll of center-folded wrap 100 is shown.Because it is a new roll that has not been presealed, leading edge 101, aswell as base 103, is open. Accordingly, L-sealer bar 116 is broughtagainst the sealer wrap to seal the leading edge 101. This being done, theL-sealer bar is lifted and as shown in FIG. 15 (as well as in thepreceding examples), product 104 is placed between the sealer wrap sides106 and 108 and the sealing frame is again brought down against the sealerwrap 100 with the product 104 contained therein. However, in FIG. 15,product 104 is not sealed into wrap 100 at open base 103 to any extent. Anopen edge remains. If the user wishes to make use of a product that isonly partially wrapped, (as is disclosed in U.S. Pat. No. 4,697,401 toKessler), then the product has been sealed with one open end as desired byKessler without the need of a cutting mechanism. On the other hand, if itis desired to seal the product with an integral tear tab 121, then asshown in FIG. 16, the product 104 and its surrounding wrap must bereadjusted. It must be turned so that edge 103 is now at a right angle toits original position. L-Sealer bar 116 is again brought down against thewrap surrounding product 104. Its leg portion 116a is now arrangedparallel to edge 103 but importantly does not extend the full length ofthat edge. Instead, its extension is interrupted by leg portion 116b whichlies at right angles to edge 103 and extends beyond that edge. It formswith sealed side 101 integral rip tab 121. L-sealer bar 116 is then liftedand as shown in FIG. 17 a product with an integral and open rip tab 121has been formed ready for delivery or shrink wrapping. Meanwhile, a newproduct 104 is introduced into the remaining wrap 100 and the processdescribed above is again repeated.
The present invention provides an expedited and superior means for wrappingan item with a rip tab. The step of punching openings in the wrap iseliminated since rip tab 120 acts as the main vent. An integral rip tab isprovided without any slowing of the known method of packaging and, shouldthe user wish a device sealed on all but one side, the invention disclosesa means of attending to this without the necessity of a cutting means. Thepresent invention contemplates various modifications to the sealing barsnow used to result in products being sealed only partially, sealed in acircle or any other geometric form, and sealed with an integral rip tab.The drawings are not necessarily to scale and are meant as illustrativeonly. The present invention is claimed as follows.