US2983087A - Vacuum packaging - Google Patents

Description

5 Sheets-Sheet 1 Filed May .10, 1955 FIG. 4

Inventor Hubert Percival Schofield K Attorney May 9, 1961 I H. P. SCHOFIELD VACUUM PACKAGING 3 Sheets-Sheet 2 Filed May 10, 1955 Inventor Hubert Percival Schotiuld Ute Patented May 9, 1961 VACUUM PACKAGING Hubert Percival Schofield, 197 'Abbotts Drive, Wembly, England Filed May 10, 1955, Ser. No. 507,359

2 Claims. (Cl. 53-14) The present invention relates to the production of airtight sealed packages of plastic, flexible or other yieldable material.

The primary object of the present invention is to provide simple means for evacuating air from, and sealing, packages of the kind referred to, in order to preserve the commodities contained therein until the time arrives for their consumption or use. An example of this arises in the packaging of alimentary material such as sandwiches or meat where the exclusion of air has the eifect of preventing the development of bacteria and the maintenance of the contents in a fresh condition until such time as the seal is broken.

In the production of a package according to the present invention there is used an insert of cardboard, metal or other relatively stiff material which has a hole therein and a slot extending from said hole to one of its edges to enable suction applied to the hole in the insert, when the latter is located coincidental with a corresponding hole in the wall of the package, to be exerted substantially uniformly within the package over the entire perimeter of the insert. p 7

The invention also includes the step of transversely sealing a package across its entire width both above and below the insert so that subsequent to the application of vacuum and sealing the insert lies wholly within the package yet outside the commodity containing part thereof.

In the preferred form of construction of insert, this has a dual function in that after being located within the mouth of a package with the hole of the insert coinciding with coaxial holes in opposed side walls of the package, and after the said mouth has been sealed with the insert enclosed within the package it is adapted to operate not only in the application of vacuum extensively within the package but also in supporting the package during the application of said vacuum thereto through the coincident holes and during the final sealing of the package with the insert isolated from the commodity containing part thereof.

The method of production as a whole is characterised in that a flat element of cardboard, metal or other relatively stiff material, which has a hole therein and a slot extending from said hole to one of its edges to enable suction applied to said hole to be exerted substantially uniformly over the perimeter of the element, is inserted into the mouth of a commodity containing package with its hole coincident with those in the package walls, the edges of the mouth are sealed to enclose the inserted element, vacuum is applied to the coincident holes to partially or wholly evacuate air from the package, and the package is finally sealed to isolate the inserted element from the commodity containing part of the package.

The initial sealing above the insert may 'be of a temporary nature achieved for example by the use of clamping jaws, i.e. it may be maintained solely until the required vacuumizing and final sealing to isolate the insert from the commodity containing part of the package have been achieved. This is particularly the case where after the commodity retaining part of thepackage has been scaled from the insert retaining part it is desired to remove the insert for any reason, such as for example to enable it to be used afresh in the application of vacuum to other packages. Otherwise the seal above the insert may be as permanent as that isolating the insert from the contents and may be applied in the same manner.

It is also to be understood that where desired an inert or neutral gas, powders or liquids may be inserted into the packages at the termination of the vacuumizing step and prior to final sealing.

The invention is more particularly described with reference to the accompanying drawings in which:

Figure l is a view of a sealed package with the insert isolated from the enclosed commodities.

Figure 2 is a section on the lines 22 of Figure 1.

Figure 3 shows the insert in plan view.

Figure 4 is an end view of the insert of Figure 3.

Figure 5 is a diagrammatic representation of the cycle of operations in the automatic handling of a package for vacuumizing and sealing purposes.

Figure 6 is a diagrammatic representation of a general assembly utilised in the production of a sealed and commodity retaining package.

Figure 7 is .a diagrammatic view on a larger scale of each of the heat sealing rollers of Figure 6.

Figure 8 is a diagrammatic representation of an automatic mechanism for use in applying vacuum to the packages.

Figure 9 is a corresponding end view of the mechanism of Figure 8.

Figure 10 is a diagrammatic plan view showing the relative disposition of the parts of a number of the elements of Figure 8.

Figures 11 and 12 are diagrammatic representations showing how sealing of a package may be achieved for a period during its continuous progress through a mechanical handling machine, as distinct from an instantaneous sealing operation. 7

In the construction according to Figures 1-4, a package or bag 10 of flexible, pliable, resilient or otherwise yieldable material such as plastic, cellulose, paper or even metal foil, has front and rear walls 11, 12, sealed at their lower ends 13. Perforations 14 are formed adjacent the upper endor the open mouth of the package .in both opposite walls to register one with the other and with a perforation 15 in an insert 16 of flat cardboard,

thin metal or other relatively stiff and thick material,

tions simultaneously in the respective elements when the' insert 16 is located in its operative position within the mouth of the package 10, or again the holes 14, 15 may be formed during manufacture of the packages and the inserts respectively, i.e. before they are brought together.

Bearing in mind that the insert 16 is not intended for insertion in that part of the package under vacuum and therefore its shape is not likely to be distorted as happens to the package itself when it collapses around an object, any printed matter on the insert may be easily read, whereas printed matter on the package would become very distorted and unreadable Printing on the cardboard inserts instead of the packages is also desirable,firstly, because it is much simpler and cheaper and, secondly, it is possible to have a standard package for a very large range of products and only the printed matter on the cardboard inserts need be diiferent.

The required indexing of an insert 16 within the mouth of a package so that its hole will remain in registration with the holes 14 of the package throughout the handling operation is achieved by means of a pair of heat-sealed circles 17 adjacent the side edges of the package, these heat-sealed circles reducing the width of the package available to the passage of articles and thus retaining the insert in its desired position of operation provided of course that the width of the insert is merely slightly less than that of the package, but is greater than the spacing apart of the circles.

Although a single hole 14, 15 is provided in the insert and in each wall of the package as the case may be, a pair of spaced holes may be formed in each element where this is thought to be desirable for enabling a package and its contents to be supported from pins or pegs on an endless travelling conveyor and for simultaneously accurately positioning the package in travelling with said conveyor for the vacuumizing and sealing operations.

A narrow slot 18 extends from the hole 15 to an edge 19, which preferably is the lower lateral edge, of the insert 16. For the purpose of meeting the particular requirements either of the commodities to be housed in the packages, or the nature of the packaging material and its thickness, the speed of vacuumizing may be varied by using inserts 16 of different thicknesses and/or slots 18 of different widths. In this respect it will be appreciated that when suction is applied to a package through the holes 14 of the package walls, the hole 15 of the insert and the slot 18, a passage of substantially triangular cross section, the hypotenuse or longer width of which is constituted by the edges of the insert, is available around the entire perimeter of the insert to ensure a relatively slow application of the vacuum to the package in contrast to instantaneous application which would have the eiiect of causing the package to adhere to its contents at different places tending to trap air in pockets within the package. Thus the width of the slot 18 in each insert should be so arranged, in proportion to the thickness of the cardboard, that under the heavy atmospherical pressures created on the outside of the container by the vacuum inside, the material of the container could not collapse inwards sufficiently to seal off the package before all the air was exhausted; the thickness of the cardboard will also provide for the package collapsing tightly around it yet still leaving a triangular shaped opening through which air can be evacuated. In general, it follows that the thinner the wall thickness of the package the thicker the cardboard should be, and also the narrower the slot, thus preserving an adequate space for air flow and minimising the risk of the package collapsing in a manner likely to leave isolated air pockets and to prevent total exhaustion.

The heat sealed circles 17 in the package walls may have V shaped indentations 29 therein to assist in severing the material forming the walls when it is desired to obtain access to the sealed contents. Conveniently the angle of i the V shaped indentations is directed towards the commodity retaining part of the package in order to direct the tears towards said portion.

As may be seen from Figure 5, the cycle of operations in the mechanical handling of commodity containing packages of the kind illustrated in Figure 1, may be continuous; thus the packages may be carried by a continuously travelling endless conveyor 21 successively through a number of stations at which different operations are performed. Thus the packages 10, each with an insert 16, may manually be hung on the conveyor belt 21 at station 22, in a prefilled condition, or they may be prepared and filled at said station. They are then conveyed to station 23 at which the mouth of the package above its insert is sealed either temporarily, such as for example by means of clamping jaws fitted with resilient pressure pads and travelling with the conveyor, or permanently until access to the commodity within the package is desired,

in which latter event heat-sealing may be achieved in any one of a number of well known methods, such as for example with the aid of heated sealing rollers.

The packages then travel towards the station 24, at which vacuum is applied, and if desired the insertion of an inert or neutral gas, whereupon they move to the station 25 at which sealing of the packages to isolate the inserts 16 from the commodity containing parts of the packages is performed. The stations 24 and 25 may in fact overlap inasmuch as the final sealing operation of the station 25 may commence and indeed be completed before the vacuum application is terminated. Removal of the filled and sealed packages from the conveyor 21 is achieved at station 26. In the conveyor belt 21 shown in the general arrangement illustrated in Figure 6, and in the diagrammatic representations oi Figures 8 and 9 spaced pegs 27 are provided so as to receive the packages by engagement within the holes 14 thereof and the holes 15 of the inserts. Each peg 27 may support a rubber or the like washer (not shown) at that end where it is carried by the conveyor to form a resilient seating for the vacuum or the like applicating device when this is applied to the peg between the initial and final sealing stages of operation on the package it sup ports.

As may be seen from Figure 6 the endless conveyor 21 in its displacement in the direction of the arrows, is adapted to bring the packages supported on its pegs 27 into engagement with a heat sealing roller 28 of any desired form whereby, by virtue of the contact between ecah package 10 and the roller 28 as the former travels tangentially to the latter, the package is transversely sealed at its mouth along one or more lines or a band 28a determined by the heat-sealing periphery of the roller. A roller 29 located on the reverse side of the outward run of the conveyor 21 is adapted to hold up the conveyor 21 and each package 10 to this upper heat-sealing roller 28 as pressure is applied by the latter to the package.

Conveniently and as shown in Figures 6 and 7 the rollers 28, 29 are enclosed within endless belts 30 which over the major part of their length are maintained out of contact with the rollers by resiliently loaded jockey pulleys 3 1 so that the belts themselves over a portion of their respective traverses are in contact with the packages 10 during the displacement of the latter so as to enable at least a low pressure to be applied for a period of time to the packages immediately after heat-sealing has been effected. Again, rigid pressure plates 32 loaded by springs 32a are adapted to guide the belts over those portions of their paths where they are required to maintain pressure contact with the packages. The small pressure belts 30 around the rollers 29 are made of a material which will not adhere to hot plastic.

After leaving the upper sealing roller 28 and its associated belt 39, each package moves towards the station at which vacuumizing is effected. Although not shown in Figure 6 the application of suction commences as the leading edge of each package 10 is about to enter the bight between a lower sealing roller 33 and a corresponding roller 34 in engagement with and on the opposite side of the outward run of the conveyor 21. By lower sealing roller is meant the roller for heat sealing each package immediately below its insert, i.e. along lines or a band 33a (Figure 1), to isolate this from the commodity retaining part. The suction effect is discontinued when the rear edge of each package has just passed through the bight between the rollers 33, 34. Conveniently, and as shown in Figure 1, the sealed band 33a extends between the opposite heat sealed circles 17 and the V shaped indentations 20 therein, but if desired it may span the package at a position slightly below said circles.

The sealed packages are removed from the conveyor 21 in the region of a roller 35, a number of which may '5 be provided throughout the length of the conveyor to maintain this horizontal. The conveyor at the end of its run passes around a guide roller 36' to commence the return run in which the cycles of operations is repeated, and in this respect the rollers 34, 29 again function respectively to hold up the conveyor and its packages during the application of upper sealing by a sealing roller 37 and lower sealing by another roller 38.

The upper heat-sealing rollers 28, -37 and the lower heat-sealing rollers 33, 38 may if desired be replaced by flexibly or resiliently cushioned sealing jaws diagrammatically represented at 39 in Figures 11 and 12. These jaws whenin gripping engagement with opposed walls of a package to seal them are adapted to hunt on an endless conveyor so that they travel with the packages during the sealing operation over a predetermined path of package displacement and then are returned out of contact with the packages to their starting positions for repeating the sealing operation on following packages. Thus the'jaws may be displaced along an endless path represented by the perimeter of a multi-sided figure, such as for example the rectangle 40 of Figure 11 or again the triangle 41 of Figure 12 one side only of which constitutes part of the displacement path of the packages on the conveyor 21 during sealing and the application of vacuum.

A suitable device of a mechanical handling machine for controlling the'application of vacuum to the packages as they travel continuously with the conveyor 21 over the distance between the sealing rollers 28, 33 or again over the distance between the sealing rollers 37, 38 is diagrammatically illustrated in Figures 8-10. In these figures a long arm having a rigid head part 42 and a resilient shank 43 is pivoted to a frame of the machine at 44 and is urged by a spring 45 towards the left hand side of Figure 8, to take up the position shown in Figure 8, i.e. against a fixed stop 48. The resilient shank 43 is normally urged towards the vertical plane of the conveyor 21, i.e. towards the left in Figure 9 whilst the rigid head part 42 which is substantially of T shape carries the vacuum appliance 46 and its lead 47.

An arm 49 is pivotally mounted at 50 to a fixed part of the machine and is urged towards the left (Figure 8) by a spring 51, anchored at 52, against a stop 53 determining its limiting end position. This arm 49 is located within the path of displacement of the pegs 27 with the conveyor 21 so as to be angularly displaced to the right of Figure 8 about its pivot 50 as it is engaged by each peg 27. Such angular displacement continues until the free end of the arm 49 descends below the line of travel of the pegs, whereupon on being released from engagement by a peg 27 said arm 49 springs back toward its stop 53 to impinge in said displacement against a horizontal limb 54 of a pivotal lever 55 which is normally resiliently held by a spring 56 against a stop 57 (Figure 8), and in such position lies in the path of the head 42 to the left (Figure 9). The tension of the spring 56 is greater than that of the spring 52 so that normally the arm 49 cannot reach its stop 53 whilst the limb 54 of the pivotal arm 55 lies in its path except when by virtue of its speed of return from engagement with a peg 27 the arm 49 impinges with force against the lever 55 and momentarily knocks the latter to the left against the load of its spring 56. When this occurs, the head 42 carrying the vacuum appliance which is normally held away from the conveyor, is freed so as to enable it to move toward the conveyor for engagement with a peg 27 thereof and thence be displaced with said conveyor by virtue of said peg.

An arm 58, pivoted to a link 59 by which it is supported from above as diagrammatically represented by a fixed member 60, is normally resiliently urged with its free end 61 located against a ramp 62, so that it lies in the path of the head 42 when the latter, freed from overlapping engagement with the lever 55, is in engagepurposes can be regarded as'a straight line so that the ment with a peg 27 and moves with said peg and its conveyor 21.

veyor 21 and its spaced pegs 27 travelling to the right in the direction of the arrow. When a peg 27 abuts against the upper end of the arm 59 it carries it with it until the arc of displacement of said upper end reaches a position below the pegwhereupon the arm 49 snaps back towards its stop 53 and in so doing it momentarily knocks the arm 55 and its limb 54 backwards thereby enabling the head 42, hitherto held away from the vertical plane of displacement of the pegs by the arm 55, to move towards the conveyor to an extent suflicient to cause the vacuum appliance 46 carried by the head to engage with the peg 27 and apply the required suction effort through the hole 14 of the package 10 carried by the peg. By virtue of the considerable length of the arm 43, the arc of displacement of the appliance 46 about the pivotal axis 44 of the arm, for all practical appliance 46 by virtue of the resiliency ofthe arm 43 is maintained in contact with its co-operating peg 27 until the head 42 moving behind the pivotal arm 58, i.e. between the latter and the conveyor 21, slides on to the ramp 62. It will be appreciated that the operative zone of the ramp 62 at which separation of the appliance 46 from its peg 27 takes place is such that by the time the head 42 reaches said zone it will have lifted the arm 58 from engagement with the ramp and passed between it and the ramp, thereby enabling the arm 58 to resume a position with its free end 61 engaging the ramp. Accordingly in returning to its original position the arm 43, with its head 42 and vacuum appliance 46, is not only pulled by the spring 45 to the left in front of the arm 58 (Figures 8 and 10), but it is also displaced away from the conveyor 21 and its pegs 27 to such an extent that, by the time it reaches a position to the left of the arm 58 (Figure 8), it is automatically reset in front of the arm 55 ready for the vacuumizing operation on the package 10 carried by the next peg 27.

It will be appreciated that numerous modifications may be adopted without departing from the scope of the invention as determined from the claims. Thus for example if the insert 16 is not to be incorporated as part of the final package for advertising or descriptive purposes, it may take the form of a tongue of metal, cardboard or other rigid or stiff material which is mounted upon the vacuumizin-g and sealing machine and is automatically inserted into a package before the temporary sealing thereof, and is automatically withdrawn from the package after the final sealing has been performed. As in the insert of Figures 3 and 4 this tongue is holed at 15 and slot-ted at '18 between the hole and one edge 19 of the tongue.

Where a removable insert capable of repeated use is vacuum application and lower sealing along the band 33a of the same package, may be achieved with the aid of a composite head with the vacuum orifice thereof located between upper and lower sealing jaws or rollers.

It will be appreciated that changes in the details, which have been herein described and illustrated for the purpose of explaining the nature of the invention, may be made by those skilled in the art without departing from,

the principle and scope of the invention as determined by the appended claims.

I claim:

l. The herein described method of forming a vacuumized package comprising, forming a tubular sleeve of heat sealable film having closed sides and at least one open end, forming heat sealed spots in opposite sides cooperating to define a lower fill compartment and an upper wall spacing member receiving compartment, forming an aperture in at least one wall of said last named compartment, placing fill in the fill receiving compartment, and placing a thick wall spacing member having a slot formed therein in communication with one edge thereof in the member receiving compartment with said slot in registry with the wall aperture by orientation of said one edge of the member against the heat sealed spots with said slot opening from said one edge of the member toward the fill receiving compartment, sealing the ends of the sleeve, and evacuating the interior of the sealed sleeve through the member slot and sleeve aperture and providing a transverse seal isolating the compartments.

2. The method defined in claim 1 modified by providing registering apertures in both walls of the sleeve by simultaneously punching through the opposing walls of the sleeve with the wall spacing member therein and with the apertures registering with the slot in the spacing member.

References Cited in thefile of this patent UNITED STATES PATENTS way;

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