US 3090174 A
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y 1963 e. H. KRAFT 3,090,174
PACKAGING METHOD AND APPARATUS Filed Aug. 24, 1960 4 Sheets-Sheet l [zzvezzzur Gfa/Pf HOW/9X20 mwrz y 1963 G. H. KRAFT 3,090,174
PACKAGING METHOD AND APPARATUS Filed Aug. 24, 1960 4 Sheets-Sheet 2 fax/12 far 1W WJMMA MM Jig 5 May 21, 1963 e. H. KRAFT PACKAGING METHGD AND APPARATUS 4 Sheets-Sheet 3 Filed Aug. 24, 1960 May 21, 1963 s. H. KRAFT PACKAGING METHOD AND APPARATUS 4 Sheets-Sheet 4 Filed Aug. 24. 1960 A m afar 650/?65 HOW/7P5 K541?- B XM, wmm uw 2 M4 United States Patent Of 3,090,174 PACKAGING METHOD AND APPARATUS George Howard Kraft, Wilmette, Ill., assignor to National Dairy Products Corporation, Chicago, 11]., a corporation of Delaware Filed Aug. 24, I960, Ser. No. 51,740 4 Claims. (CI. 53-22) The present invention relates generally to the art of packaging, and is particularly directed to a method and apparatus for packaging materials in a tubular wrapper.
In the packaging of many products, for example food products such as cheese, in a wrapper of flexible sheet material, there is commonly utilized packaging equipment which provides a tubular wrap for a plurality of the units to be packaged. Such units are disposed in spaced-apart relationship, within the tubular wrap, which is then sealed and severed intermediate the units to produce the individual packages. The present invention relates to improvements in such equipment, particularly with respect to the formation of the individual packages.
It is the primary object of the present invention to provide an improved method and apparatus for the packaging of articles in a tubular wrapper of flexible sheet material. A further object of the invention is to provide apparatus of the type referred to, which includes means for pro gressively pressing the tubular wrapper together, intermediate the articles to be packaged, from a position adjacent one of the units to a position adjacent the succeeding unit. Still another object of this invention is to provide improved means for injecting a gas into a tubular wrapper enclosing a plurality of spaced-apart articles and for then pressing the tubular wrapper together so as to close the wrapper intermediate the articles and expel the gas rearwardly in the tube past succeeding articles. Other objects and advantages will be apparent from the following description of the selected embodiments of the invention, which are illustrated in the accompanying drawings wherein:
FIGURE 1 is a schematic illustration of a packaging machine embodying features of the invention;
FIGURE 2 is an enlarged, fragmentary view of the structure in FIGURE 1, with parts broken away and in section to more clearly illustrate certain details;
FIGURE 3 is a top plan view of the structure in FIG- URE 2, with parts broken away;
FIGURE 4 is an enlarged perspective view of a portion of the structure seen in FIGURE 1;
FIGURE 5 is a sectional view, taken along the line 5-5 in FIGURE 4; and
FIGURE 6 is a of the invention.
As noted particularly in FIGURE 1 of the drawings, the features of the present invention are illustrated in connection with a packaging method and apparatus, which is particularly adapted for wrapping rectangularly shaped units, such as blocks of cheese or stacks of rectangular slices of cheese. The illustrated machine 10 comprises generally a feed conveyor mechanism 12, a wrapper feed mechanism 14 which is adapted to provide a tubular wrap for a plurality of the units U to be packaged as the latter move forwardly of the machine from the feed conveyor 12, a gassing apparatus 16 for injecting a preservative gas into the tubular wrapper, a conveyor means 18 for initially forming the individual packages, and means 20 for sealing the tubular wrapper intermediate the units therein and for severing the wrapper so as to provide separate packages which then are discharged by means of a discharger conveyor 22.
In mechanism of the type referred to, there have been some ditficulties with respect to the formation of the individual packages from the wrapper enclosed units, and
perspective view of a modified form Patented May 21, 1963 particularly with foods, such as cheese, there have been difiiculties with respect to effectively evacuating the air from the wrapper and/or introducing a preservative gas so as to achieve a maximum shelf life for the packaged item which might otherwise spoil or deteriorate in the presence of air. The present invention is particularly directed to novel and improved means for handling units being packaged in the above described manner, which means is employed between the position of forming the tubular wrapper, indicated at W in FIGURES 2 and 3, and the final formation of the individual packages. More particularly, this invention is especially concerned with a novel gassing device and method, and a novel lug type conveyor which is positioned adjacent the forward end of the machine and which serves to initially form the individual packages.
The gassing device 16 is arranged to provide for entry of a preservative gas, such as heated carbon dioxide, into the tubular wrapper W" as it is being formed and in a manner such that the gas is directed forwardly through the tubular wrapper toward the closed end thereof. The conveyor means 18 is employed generally to press the top and bottom portions of the tubular wrapper together, at positions intermediate the units U to be packaged, with the pressure being initially exerted adjacent one unit and then expanding over an area of the tubular wrapper in the direction of the succeeding unit, with the conveyor 18 also providing proper tensioning of the tubular wrapper to keep the wrapper taut and in conforming relation to the units being packaged.
The sheet material used in the formation of the tubular Wrapper is provided by a supply roll 24 disposed above the packaging machine, and the end of this sheet material is suitably fed into a forming shoe or plow 26 disposed at the discharge end of the feed or intake conveyor 12. Although various types of suitable wrapping material can be used on the machine, it is preferable that the wrapper be of quite flexible material and adapted to pressure and/ or heat sealing. The forming shoe 26, seen particularly in FIGURE 5, places the wrapper into overlying relation to the spaced-apart units as they are propelled forwardly from the feed conveyor 12, and the wrapper is then folded downwardly along opposite sides of the units and along the bottom of the units in any suitable known manner. The precise manner and mechanism for performing this operation is not a portion of the present invention and, therefore, need not be described in detail. In one type of packaging machine, the opposite side edges of the wrapper are disposed beneath the units being packed in abutting relation to each other, so as to provide a downwardly extended fin, and this fin is then folded and sealed in flush relation to the bottom surface of the units, as by means of suitable plows or other forming devices not shown. Consequently, at this stage of the packaging operation there exists an elongated, tubular wrapper W" having a plurality of spaced-apart units U" therein.
In order to more effectively form individual packages from the tubular enclosed, spaced-apart units, and to pro vide other advantages to be noted herein, there is provided the conveyor means 18 comprising a pair of com veyor mechanisms 26 and 28, which are disposed adjacent the forward end of the packaging machine in vertically spaced-apart and generally aligned relation. These conveyors are seen particularly in FIGURES 2 and 3 of the drawings, wherein it will be noted that the lower conveyor 28 comprises generally a supporting frame structure 32, mounting a pair of rotatable supports 34 and 36, respectively, at opposite ends of the frame, and an endless belt 38 or the like is positioned on the rotatable supports. In the illustrated embodiment, the forward end of the lower conveyor frame 32, that is the end toward which the product is moving, is suitably mounted on the main frame 42 of the machine for pivotal movement about the axis 40 of the forward rotatable support 34, and means is provided between the opposite end of the frame structure 32 and the supporting main frame 42 to permit vertical adjustment of the rear portion of the conveyor 28. More particularly, the conveyor frame 32 has fixed thereto a bracket 44 including a horizontal flange with an opening therethrough receiving a bolt 46 carried by the main frame 42. A pair of nuts 48- are threaded onto the bolt 46 on opposite sides of the bracket flange, to thereby selectively determine the elevation of the rear end of conveyor 28.
The endless conveyor belt 38 is of flexible material, such as rubber or a flexible fabric, and the upper run of the conveyor belt is guidedly supported intermediate the rotatable end supports 34 and 36 by a metal plate 50 or the like. This metal plate is formed so that the first portion of the upper run of conveyor belt 38 is inclined upwardly and the latter portion of the run is disposed in a generally horizontal plane. At longitudinally spaced positions along the conveyor belt 38, there are provided a series of transversely disposed, flexible elements or lugs 52. In the illustrated embodiment, each of the lugs 52 is fixed to the conveyor belt 38 and comprises a block of rubber having a plurality of parallel, transverse slits 54 extending downwardly from the outer surface of the lug a substantial distance. The cuts or slits 54 add considerably to the flexibility of the lug in the direction of their movement with the conveyor. The lugs 52 are spaced along the conveyor belt, so as to conform with the spacing between the units U being packaged, and the lugs are of a size, lengthwise of the conveyor belt, generally corresponding with the distance between the spacedapart units held in the tubular wrapper. The transverse dimension of each lug is, of course, at least as great as the width of the tubular wrapper The upper conveyor means '26 is generally similar to the lower conveyor means 28, and like parts thereof will be similarly numbered with a prime sutfix The conveyor 26 comprises generally a frame structure 32' mounting a pair of rotatable elements 34' and 36', respectively, at opposite ends thereof. These rotatable elements are similar to those provided for the lower conveyor 28 and are in the form of transversely grooved rollers, which are adapted to drivingly engage corrugations formed on the underside of the flexible conveyor belt. The frame structure for the upper conveyor 26 is also journaled on the main frame for swinging movement about the forward axis 40', and frame 32' supports a metal plate 50', defining the path of the lower run of the upper conveyor belt 38. The initial or rearward portion of the path thus defined is inclined downwardly and the latter or forward portion is generally horizontal.
Consequently, it is seen that the lower and upper conveyor belts 38 and 38' have a maximum spacing at the throat defined by the rollers 36 and 36', adjacent the intake end of the conveyor means 18, and the path of the conveyor belts converge toward an intermediate position along the run of the conveyors, with the run of the conveyor belts then assuming a generally parallel course to the discharge end thereof.
"l he upper conveyor belt 38 also has a series of flexible elements or lugs 52' mounted thereon, and these lugs are disposed and spaced identically with the lugs 52 on the lower conveyor belt 38, so that as the two conveyor belts are moved in the direction of the path of movement of the wrapped units one of the flexible lugs 52 on the lower belt 38 is disposed opposite to a flexible lug 52' on the upper belt 38'. Furthermore, the operation of the two lug conveyors 38 and 38' is timed so that a pair of the lugs 52 and 52' 'multaneously engage the upper and lower surface of the tubular wrapper W, intermediate a pair of the units U to be wrapped, with the initial engagement being along the leading edge of the resilient lugs while the latter are inclined with respect to the horizontal path of the tubular wrapper. ment of the lugs, through the paths verging plates 50 and 50, increases this engagement of the wrapper by the lugs over an area extending rearwardly of the tubular wrapper, while the lugs are penetrating deeper into the tubular wrapper intermediate a pair of the units.
There is also provided, adjacent the lug conveyors 26 and 28, a pair of rotatable discs or the like, each having a plurality of tucker fingers 62 mounted thereon in circumfercntially spaced relation. These discs are suitably driven for rotation in timed relation to the movement of the conveyor means 18, so that as the lugs 52 and 52' are pressing the tubular wrapper together, a pair of the tucker fingers 62 move into engagement with opposite side walls of the wrapper and tuck the side Wall portions into position between the upper and lower wrapper surfaces. Consequently, as the lugs compress the wrapper together, they produce a fin like section 64 (FIGURE 2) between adjoining units, which section has a width corresponding to the width of the units U being packaged. Of course, the tucker fingers 62 are withdrawn prior to the final compression of the wrapper by the lugs 52 and 52' wherein the upper and lower surfaces of the wrapper fin are brought into tight engagement, as seen to the right in FIGURE 2.
The described action of the pairs of resilient lugs 52 and 52' is not only effective in providing the fin-like sections 64 intermediate the units, which are ultimately severed transversely to provide the individual packages, but these lugs are also of considerable advantage in conforming the tubular wrapper to the shape of the unit and in forcing the air or preservative gas out of the individual package being formed. It will be noted, particularly in FIGURE 2, that the initial compression on the tubular wrapper W by a pair of the lugs 52 and 52' is along a line closely adjacent the rearward edge of one unit U, so as to smooth the wrapper against the trailing side of such unit. Furthermore, the pressure exerted by the lugs on the wrapper is in the nature of squeezing the wrapper together in a progressive manner from front to rear of the space intermediate the units. This squeezing effect is important in evacuating lair and/or a preservative gas rearwardly of the wrapper, so that air is not trapped within the individual package being formed.
With respect to the packaging of food items, such as cheese which is susceptible to spoiling in the presence of air, attention is particularly directed to the gassing device 16 shown in FIGURES l, 4 and 5. As indicated previously, this device provides for the introduction of a preservative gas into the tubular wrapper W adjacent the point of formation of the latter by the forming shoe 26. Generally, the gassing device 16 comprises a source (FIGURE 1) of heated CO or other preservative gas, which is in communication with a manifold 72 disposed below the path of the cheese units. Extending upwardly from this manifold are a plurality of tubes 74, which are in communication with openings 76 (FIGURES 4 and 5) provided in a plate structure 78 disposed along the bottom of the wrapper forming means 26. The dischargeof the preservative gas through the openings '76 is effective to direct the gas forwardly of the tubular wrapper so as to envelope the plurality of spaced-apart units therein. Generally, the tubular wrapper will be effectively closed off by the action of the lugs 52 and 52' adjacent the forward portion of their path of engagement with the wrapper, and such action of the lugs will determine the extent of flow of the gas. As the lug conveyors 26 and 28 operate in the previously described manner to squeeze the tubular wrapper intermediate the units, the preservative gas, as well as any air in the wrapper, is swept rcarwardly of the wrapper and is ultimately discharged to the atmosphere. The described means for introducing the preservative gas eliminates the need for entry into the tubular wrapper of any conduit or the like, and thus permits Continued movedefined by the conwrapping of the units in tightly conforming relation between the wrapper and the It will also be noted that the lug conveyor means 18, after having pressed the tubular wrapper portions together, continues to hold such portions together during the latter portion of the travel of the conveyor. Thus the fins 64 formed between the units being packaged are positively held together, and also the action of the lug conveyor on the wrapper W is effective to provide proper tension on the tubular wrapper, so that the latter is properly drawn through the machine into a position for engagement by suitable sealing and severing mechanism 20 which then seals the fins 64 and cuts them along an intermediate transverse line to form the individual packages. In the illustrated embodiment, the tubular wrapper is sealed and severed by the means 20 which includes a pair of rotatable elements 80 and 80' (FIGURE 1), each having one or more pairs of sealing bars 82 astride a movable knife 84. As the wrapper enclosed units move forwardly of the machine, a sealing and serving unit on each of the rotatable elements 80 and 80' moves into position to heat seal a forward section of the fin 64 formed between units, out the fin transversely, and then heat seal the rearward section of the fin, in sequence. The forward unit is then discharged on to a conveyor, such as the transverse take-off conveyor indicated at 22.
It will be understood that suitable drive means is provided for the described structure, and that such drive means is effective to provide properly timed operation of the various portions of the packaging machine to produce the described mode of operation. It is believed that a more detailed showing and description of such drive means is unnecessary for a proper and complete understanding of the invention disclosed herein.
A modified form of the lug conveyor means described above is shown in FIGURE 6. Generally, the modified conveyor, indicated by the numeral 90, operates in a manner somewhat similar to that described with respect to the conveyor 18, but in addition it seals the fins 64 intermediate the packaged units by means of heat.
More particularly, the conveyor 90 includes a pair of endless conveyor mechanisms 92 and 94, which are disposed in vertically spaced-apart relation with the adjacent paths of the conveyors converging toward the forward end of the packaging machine. The frame structures for these conveyors are preferably similar to those of the previously described conveyor 18, affording the adjustment of the conveyors relative to each other. The lower conveyor 92 includes a pair of endless chains 96 each disposed around a pair of sprockets 98 and 100 positioned, respectively, at opposite ends of the conveyor. At longitudinally spaced positions along the chains 96 there are provided a series of transversely disposed sealing bars 102, which may be of silicon or the like, and these bars are spaced to conform with the spacing of the units U being packaged. The dimension of the bars, lengthwise of the conveyor, generally corresponds with the distance between the units U held in the tubular wrapper.
The upper conveyor 94 also has a pair of endless chains 96' which are disposed around the sprockets indicated at 98' and 100'. A series of heater bars 104 are secured in transverse relation to the chains 96' at positions therealong conforming with the spacing of the sealer bars 102, so that the heater bars 104 and sealer bars 102 may converge toward each other during their travel through the throat of the conveyor 90, and finally mate at the end of their run, as indicated in FIGURE 6. During this converging movement of the heat and sealer bars, they press the portions of the tubular wrapper W inter mediate the units U together, to form the fins 64 (FIGURE 2), and upon final pressing engagement of the heater and sealer bars against the fin the latter is heat sealed in readiness for subsequent cutting of the fin to form the individual package.
Suitable means is provided for supplying heat to the heater bars 104, and such means is illustrated as including a contact brush 106, associated with each bar, which has an electrical connection with the heater bar 104 and which rides upon an electric rail 108 provided with electrical power from a suitable source (not shown).
Although shown and described with respect to particular embodiments, it will be apparent that various other modifications might be made without departing from the principles of the invention.
1. Packaging mechanism comprising means for continuously forming a strip of substantially gas impervious, flexible sheet material into an elongated, open-ended tube which contains a series of the units to be packaged disposed in spaced-apart relationship lengthwise of the tube, means for filling said tube with preservative gas, means for progressively pressing said tube together at positions intermediate the units to be packaged so as to collapse said tube at said positions and to force said gas along said tube toward said continuous tube forming means, said last mentioned means comprising a plurality of pairs of yieldable elements positioned for movement into engagement with opposite surfaces of said tube at said positions intermediate the units, each of said pairs of elements presenting a generally fiat, resilient outer surface and being movable through paths whereby the tube is initially engaged by said pair of elements by the leading edge thereof and such initial engagement is maintained while the area of contact becomes increasingly greater until said elements are in face-to-faoe gripping engagement with the tube, and means for tucking in the side walls of the tube while the tube is being collapsed so as to provide a collapsed portion having a width corresponding with the width of the units.
2. Packaging mechanism comprising means for continuously forming a strip of substantially gas impervious, flexible sheet material into an elongated, open-ended tube which contains a series of the units to be packaged in spaced-apart relationship lengthwise of the tube, means for filling said tube with a preservative gas adjacent its position of formation, means for pressing said tube at positions intermediate the units to be packaged so as to collapse said tube at said positions and to force said gas rearwardiy along said tube toward said continuous tube forming means, said last mentioned means comprising a plurality of pairs of yieldable elements positioned, respectively, on a pair of endless belts for movement into en gements with opposite surfaces of said tube to said positions intermediate the units, each of said pairs of elements being movable through converging paths toward said tube and each of said elements presenting a generally flat resilient outer surface having a plurality of transverse slits therein, whereby the tube is initially engaged by said pair of elements by the leading edge thereof and the area of contact becomes increasingly greater, while said initial engagement is maintained, until said elements are in faceto--face gripping engagement with the tube.
3. Packaging mechanism comprising means for conveying a series of spaced-apart units through a predetermined path, means for continuously forming a strip of substantially gas impervious, flexible sheet material into an elongated, open-ended tube which contains a plurality of said units to be packaged, means for filling said tube with a preservative gas adjacent its position of formation, means for progressively pressing said tube at positions intermediate the units to be packaged so as to collapse said tube at said positions and to force said gas rearwardly along said tube toward said continuous tube forming means, means for tucking in the side walls of said tube at said positions while the tube is being collapsed so as to provide a collapsed portion having a Width corresponding with the width of the units, said tube pressing means comprising a plurality of pairs of yieldable elements positioned for movement into engagement with opposite surfaces of said tube at said positions intermediate the units, each of said pairs of elements being movable through converging paths toward said tube and each of said elements being formed of resilient material and having a plurality of parallel cuts in its outer surface transversely of the path of movement of said elements, where by the tube is initially engaged by one of said pair of elements along the leading edge thereof and the area of contact with the tube becomes increasingly greater, while said initial engagement is maintained, until said elements are in face-to-face gripping engagement with the tube of collapse the engaged portion, and means for sealing and severing the tube transversely of the collapsed portion to produce individual packages.
4. A packaging method for continuously producing packaged units and which comprises successively disposing a plurality of the units to be packaged in spaced-apart relationship within an elongated tube having a single open end and formed of substantially gas impervious, flexible sheet material, continuously introducing a preservative gas into said tube and then progressively, from the closed end of said tube, collapsing said tube at positions intermediate adjacent units in a manner such that the opposite faces of the tubular wrapper are initially pressed together along a transverse line adjacent one of the units to a position adjacent the following unit and in a progressive manner between such positions, while maintaining said initial engagement, so as to progressively enlarge the area of pressure on the tube, whereby gas is expelled from between said adjacent units and forced back over said following unit, tucking in the side walls of the tube while it is being thus collapsed so as to provide a Width corresponding With the width of the units, sealing the pressed together portions of said tubular wrapper into fixed relation, and severing the wrapper at said sealed portions to provide individual packages.
References Cited in the file of this patent UNITED STATES PATENTS
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