US3492776A - Method of packaging objects between sheets secured to a frame - Google Patents

Description

Feb. 3, 1970 J. w. HARRISON ET 3,492,776

METHOD OF PACKAGING OBJECTS BETWEEN SHEETS SECURED TO A FRAME Original Filed Dec. 5, 1964 4 Sheets-Sheet 1 "will! I INVENTORS JOHN W. HARRISON BY $25318 ZZY ATTORNEY Feb 3, 1910 w, HRRRISON" ETAL 3,492,776

METHOD OF PACKAGING OBJECTS BETWEEN SHEETS SECURED TO A FRAME Original Filed Dec. 5, 1964 4 Sheets-Sheet 2 INVENTORS JQHN w. HARRISON ROBERT 123m BY 2mm ATTORNEY Feb. 3, 1970 J. w. HARRISON ETAL 3,492,776

METHOD OF PACKAGING OBJECTS BETWEEN SHEETS SECURED TO A FRAME Original Filed Dec. 5, 1964 I 4 Sheets-Sheet 5 FIG. ll

INVENTORS JOHN W. HARRISON ROBERT D. 28W Y ATTORNEY Feb. 3, 1970 J, w. HARRISON ET 3,492,776

METHOD OF PACKAGINGQBJECTS BETWEEN SHEETS SECURED TO A FRAME Original Filed Dec. 5, 1964 4 Sheets-Sheet 4 I06 I02 5 I05 IOI I04 o FIG. I3

FIG. I4

I24 I22 I20 I FIG. I7 INVENTORS JOHN HARRISON ROBERT D. :ZZWRY United States Patent Int. Cl. B65b 43/08 US. CI. 53-30 7 Claims ABSTRACT OF THE DISCLOSURE A method of packaging articles is provided wherein the articles are placed between two heat-shrinkable sheets of packaging material, which sheets are secured around the outside of a separate frame and heat shrunk, so that the articles are suspended within said frame in a taut wrapper.

This application is a division of Ser. No. 418,583, filed Dec. 3, 1964, now Patent No. 3,397,773, issued Aug. 20, 1968.

This invention relates to novel packages and to novel methods of packaging and more particularly to such packages where the product packaged is held between opposed sheets of heat-shrinkable material, the edges of which are in turn fixed to an outer frame.

It is an object of the present invention to provide a novel package that is attractive and displays to good advantage the object enclosed.

A further object is to provide a package that is simple to construct and requires inexpensive materials for its manufacture.

Another object is to provide a transparent package that is dust, air and moisture tight.

It is also an object of the present invnetion to provide a package which affords an unusual degree of protection against physical shock.

These and otherobjects of the present invention will appear more fully in the following specification and claims taken on conjunction with the accompanying drawings in which:

FIGURE 1 is an exploded cross sectional view of the components employed in forming one of the packages of our invention;

FIGURE 2 is a perspective view, partially in section, of the completed package of FIGURE 1;

FIGURE 3 is a side elevation, sectional view of apparatus suitable for use in the formation of a package similar to that of FIGURE 1;

FIGURE 4 is a further view of the apparatus of FIG- URE 3 and showing the final step in the formation of the package;

FIGURE 5 is a cross sectional, elevational view of a modified package of the present invention;

FIGURE 6 is a cross sectional, elevational view of another modified package;

FIGURE 7 is a plan view of the package having a modified frame suitable for the present invention;

FIGURES 8, 9, and 10 are perspective views showing various steps in the formation of another modified pack- FIGURES 11 and 12 are detailed, cross sectionalpviews of modified frames;

FIGURE 13 is an elevational view, partially in section, of a preliminary step in the formation of a modified package;

FIGURE 14 is a view of a further step in the formation of the package;

FIGURE 15 is a perspective view of the completed package;

FIGURE 16 is a cross sectional view of a preformed film cover;

FIGURE 17 is a view of a package employing the preformed covers of FIGURE 16.

We have discovered a new package in which the object being packaged is held suspended between two taut sheets of heat-shrinkable plastic film. The edges of the film sheets are secured to or locked around an outer frame which surrounds the object. The package is easily constructed, requires inexpensive materials and produces an unusually attractive and dramatic package.

The novel package of the present invention as shown in FIGURE 1 comprises an outer frame or ring 14 of stiff material, e.g. a stiff plastic ring, a pair of film sheets 12 and 13 of heat-shrinkable material of substantially similar size and approximately 1 mil thick, which film sheets are larger than the area defined by the frame or ring so that the outer edge of each film sheet extends well beyond the periphery of the frame. The product being packaged 11 is placed between the film sheets and both the film sheets and enclosed product are placed over the frame. The peripheral edges 15 of the fihn sheets extending beyond the frame are folded under the frame and the folded under edges of said film are selectively shrunk by the application of heat to the underside of the frame or ring. As the film edges are heated, they shrink and tighten inwardly under the frame, forming a tough elastic edge which is smaller than the frame and which results in the film sheets being locked to the frame as is shown in FIG- URE 2. The heating and the tension of shrinking cause the edges of the two film sheets to come together forming a tight hermetically sealed envelope within which the product is contained. The main areas of the film sheets lying within the frame are subsequently exposed to heat, causing the film to shrink producing a taut package which tightly holds the product in a selected position between the sheets of film.

FIGURES 3 and 4 of the drawings disclose a device which is useful in forming the above-described package. Such a device should be able to support the product and shield the main portion of the film sheets from heat as the edges of said film sheets are selectively shrink-locked to the frame. The device in FIGURE 3 consists of a base plate 37 which has a plurality of product support posts 33 in the center of said base plate and which has at its outer edge a plurality of frame support posts 34. Both product support posts and frame support posts are perpendicular to the plane of said base plate. As can be seen in the drawings, the upper portion of said frame support posts is adapted to hold or support the frame 42 of the package. A lower film face shield 32 and an upper film face shield 31 are shown in a closed or operative position in FIGURE 3 and in an open position in FIGURE 4. These shields protect the large areas of the film sheets while the edges are being heat shrunk. The opening and closing of the face shields can be accomplished by any of the various means well known in the art, e.g. by means of a two-way air operated pneumatic cylinder 35 and 36. The lower film face shield has openings to accommodate the product support posts. In FIGURE 3 a frame in the shape of a wire ring 42 is placed upon the frame support posts, a first sheet 38 of heat-shrinkable film is placed over the product support posts and over the wire ring. The product 39 is then placed upon the first sheet of heat-shrinkable film and positioned over the product support posts and a second sheet 41 of heat-shrinkable film is placed over the product and over the wire ring. The edges of both film sheets extend well beyond the wire ring. The upper and lower film face shields are brought together thereby shielding that area of the film sheets within the frame and also shielding that portion of the film on the top of the wire ring. Heat is applied to the exposed edges of the film sheets causing them to shrink and tighten under the wire ring. This device permits the selective heating of the film edges. In FIGURE 4, the film face shields are moved apart and heat is applied to the remainder of the face of the film sheets tightening the film against the product.

A modification of my invention is shown in FIGURE 5 wherein the rigid frame is in the general shape of a pie plate. The rigid frame is a frusto-conical aluminum dish 51, having a peripheral flange 52, side wall 53, and a base 54 having a polished, reflective surface. The edges 58 of the heat- shrinkable film sheets 57 and 55 are shrinklocked under the flange of the aluminum plate. The main areas of the film sheets are shrunk producing a tight package. The base of the aluminum dish serves as a reflective background for the product 56 enclosed between the taut film sheets. In producing the above package it will be necessary to modify the method described above since the lower film sheet cannot be shrunk easily because of the aluminum base. The lowermost film sheet is placed over the aluminum dish, the edges shrink-locked under the flange and the area within the flange shrunk, stretching the sheet across the face of the aluminum dish. The product is placed upon the taut film and covered with a second film sheet, the edges of which are shrink-locked under the flange of the aluminum dish and the area within the flange shrunk to complete the package. In place of a fiat polished base, it is possible to substitute a base having an irregular or multi-faceted surface.

It is also possible to employ a flanged, frusto-conical frame similar to the above except that the base portion is removed or absent, leaving an open area 64 beneath the package as is shown in FIGURE 6.

A rigid frame that is especially suitable when using square sheets of heat-shrinkable material is shown in FIGURE 7. The frame 74 is essentially circular but has four rounded projections spaced equally about the frame. The object packaged 71 is placed between opposed film sheets 72 and 73 and shrink-locked in the above-described manner. This frame prevents the thickened shrunk points of the film sheets from protruding into the transparent area or window of the package.

The term frame as employed in the present invention refers to a structure that defines a central opening. The opening defined by said frame may have any geometric shape, e.g. circular, rectangular, etc., and the only requirement is that such opening be as large as or larger than the product to be held within said opening. The only requirement for the frame is that it be sufficiently sturdy or rigid to withstand the strain imposed by the shrinking film. The frame may assume many shapes and be composed of many materials, e.g., wood, metal, plastic, cardboard, etc.

While all the frames described heretofore have been closed frames and such closed frames are generally preferred, it is also possible to employ open frames. FIG- URE 8 discloses such an open frame wherein the frame 83 partially surrounds the enclosed object 82. In this example the object is placed in the middle of a large sheet of film 81 which is folded about said object. Each half of the film is placed on opposite sides of the frame and first one half of the film is shrink-locked over the frame and then the other half is shrunk against the other side of the frame. Alternatively, both halves of the film could be brought together and shrink-locked under or against one side of the frame.

FIGURES 11 and 12 are partial cross sectional view of other frames which have different shapes suitable for holding the shrunk film edges.

The formation of a modified package of the present invention is shown stepwise in FIGURES 13, 14, and 15.

In FIGURE 13 there is shown in cross section a first frame member 101 which is circular and has a large central opening. The frame member has an upper 102 and lower 103 face which faces have a width of approximately one inch. A first sheet 104 of transparent, heat-shrinkable, thermoplastic film larger in area than the area defined by the frame and having its peripheral edge 105 extending at least one inch beyond the outer perimeter of the frame is placed over the lower face of said frame. The edge 105 of the film sheet is folded around the frame member and subjected to heat suflicent to shrink the film edge, causing it to lock against the upper face of the frame member. The object 106 being packaged is placed on the film sheet 104 on the same side as the shrunken film edge. As shown in FIGURE 14, a second frame member 107, having the same shape and size as the first frame member, is placed against the upper face of the first frame member. The shrunken film edge 105 is now hidden from view between the two frame members. A second sheet 108 of transparent heat-shrinkable, thermoplastic film, also larger in area than the area defined by the frame members and having its peripheral edge 109 extending well beyond the outer perimeter of the frame members is placed against the second frame member 107 and in so doing, covering the object 106. The peripheral edge 109 is drawn over the edge of the frame members and against the film covered lower face 103 of the first frame member. Heat is selectively applied to that portion of the film edge which is now positioned against the first frame member causing the edge portion to shrink sufficiently so that the resulting peripheral edge has a smaller perimeter than the largest perimeter of the frame members thereby locking the film edge under the frame member. Finally, heat is applied to the film faces to tighten the sheets and remove all wrinkles. The completed package, shown in FIGURE 15, reveals an object held tightly suspended between two sheets of transparent film and surrounded by a rigid frame to which the film sheets are locked.

As the film edges are shrink-locked against the frame members, the film tends to wrinkle, thicken and become slightly opaque. It is desirable, from an appearance standpoint, that such a wrinkled edge not appear on the front of the package. The method of the preceding paragraph produces such a package and in addition completely encloses the frame members within a covering of film material thereby protecting said frame members from moisture and soiling. Shrink locking one sheet of film on one side of the frame and shrink locking the second sheet of film over the opposite side of the frame is highly advantageous and permits the use of lighter weight or structurally less rigid frames. This is possible because in shrinking the film faces the strain exerted on the frame by the shrinking film is equalized. While both frame members in the preceding example may have sufiicient structural strength to either individually or collectively support the product and resist the strain exerted by the shrinking film, it is only necessary that one of the members have this structural strength. In fact, the other frame member, which in the above example would be the second frame member, may be formed of a thin, flexible material such as paper or plastic foil. The only purpose of the second frame member would be to conceal the first shrunken edge and not to support the film sheet.

An alternative procedure in the formation of the packages of the present invention requires that the peripheral edges of the film sheets be preshrunk. Heat is selectively applied to a narrow zone about the periphery of a disc of heat-shrinkable material. The heated zone shrinks rapidly and forms a cap or bell-shaped structure. The shrunken edge 121 of the disc has thickened and becomes permanently elastic. The preshrunk film sheet is shown in FIGURE 16. The diameter of the elastic edge will be less than the outside diameter of the frame memher. The elastic edge of the film disc may be stretched to permit the edge to be drawn over and around the frame edge. The elastic edge then serves to lock the disc over the frame member 122. An object 123 is positioned on the film disc 120 and a second preshrunk film disc 124 is stretched over the frame covering the object. The object is now enclosed between two film sheets which are locked around the frame member by the elastic edge portions of the film sheets. The main areas of the film sheets between the frame may be shrunk to tighten the sheets and produce the package shown in FIGURE 17.

The preferred heat-shrinkable material and the one employed in the preceding examples is an irradiated, biaxially oriented polyethylene film, specifically Alathon 14, average molecular weight 20,000 density 0.914 and having a melt index of 1.8 which has been irradiated to an extent of about 12 megarad and then biaxially stretched 350 percent in both a longitudinal and lateral direction. The irradiated, biaxially oriented polyethylene has a shrink energy of about 150 pounds per square inch in both directions at 96 C. Shrink energy is defined as the force of contraction at a given temperature when the material is restrained, more specifically, it is defined as the measurable tension produced in a fully monodirectionally restrained strip of film when heated to the specified temperature.

Other heat-shrinkable materials that will not melt or decompose under the temperatures required for shrinking may be used. Examples of such heat-shrinkable materials include but are not limited to the following: irradiated and biaxially oriented solid polymers of polyethylene, such as those described in Baird et al. United States application, Ser. No. 713,848 filed Feb. 7, 1958 (now US. Patent 3,022,543), and United States Patent 2,877,500 to Painer et al., both of which are hereby incorporated by reference, copolymers of ethylene and propylene (e.g., a 50-50 copolymer), copolymers of ethylene with minor amounts, e.g., 5 percent of isobutylene, amylene, acetylene, butadiene, butene 1 and butene 2, or block copolymers of polyethylene with a minor amount, e.g., 5 percent of polyisobutylene, blends of polyethylene with from 25 to 90 percent by weight of a copolymer of ethylene copolymerized with from 0.5 percent to 15 percent by weight of an olefin having 3 to 18 carbon atoms, graft polymers of polypropylene or polyethylene with monomers such as acetylene, butadiene, butylene, ethylene and propylene. Other materials include oriented polypropylene, oriented polyvinyl chloride, copolymers of vinylidene chloride (saran films), etc.

In place of the two opposed separate sheets of heatshrinkable material employed in the examples, one may also use a single sheet which has been folded in half as shown in FIGURE 8.

The thickness of the heat-shrinkable films may be varied for purposes of this invention.

Heat shrinking of the materials employed in constructing the packages of the present invention may be done with any of the well-known means commonly employed in the art, e.g., hot air, heated surfaces, radiant heat, etc. A convenient heat source is a hot air jet from a hot air gun.

A wide variety of products may be effectively packaged with the package of this invention and include but not limited to such items as jewelry, cosmetics, electrical devices and components, hardware, etc.

The packages of this invention provide a simple, inexpensive package suitable for a wide variety of products. Such packages have tremendous eye appeal since the object appears to be suspended in space.

The invention described in detail in the foregoing specification is subject to changes and modifications without departing from the principle and spirit thereof. The terminology used is for purposes of description and not of limitation, the scope of the invention being defined in the claims.

We claim:

1. A method of producing a package which comprises placing the object being packaged between opposed sheets of heat-shrinkable material, securing the peripheral edges of said sheets to a rigid frame thereby locking said sheets to said frame and heat shrinking said film sheets to form a taut package wherein said object is tightly held between said film sheets.

2. A method of forming a package which comprises placing the object being packaged between a pair of opposed sheets of heat-shrinkable material, wrapping the peripheral edges of said sheets around a rigid frame which encloses said object in a plane co-extensive with the plane of said opposed sheets, shrinking the peripheral edges of the sheets so as to lock the edges to the frame and thereby lock the sheets to the frame, shrinking the area of the sheets within the frame to produce a taut package.

3. A method of packaging which comprises placing an object between a pair of heat-shrinkable, thermoplastic film sheets, positioning said sheets and object over a rigid frame which defines an open area so that the object is located within the open area, folding the peripheral edges of both of said film sheets which extend beyond the frame in all directions around and under the edges of the frame, applying heat to the folded under edges of the film sheets, shrinking the edges and reducing the perimeter of the film edges below that of the largest perimeter of the frame thereby locking the film sheets over the frame, shrinking the area of the film sheets within the frame to tighten the film sheets.

4. A method according to claim 3 wherein said frame is a flanged, frusto-conical frame.

5. A method of packaging which comprises placing a first sheet of heat-shrinkable, thermoplastic film over a rigid frame which frame defines an open area, folding the excess of said first sheet which extends beyond the peripheral edge of said frame around and under said frame, applying heat to the folded under edge of said first sheet, shrinking the edge and reducing the perimeter of the film edge below that of the largest perimeter of the frame thereby locking the first film sheet to the frame, shrinking the remainder of the first film sheet to tighten said sheet, placing an object upon said first film sheet on the same side as said shrunken edge, placing a second film sheet over said object thereby enclosing said object between said second and first film sheets, folding the excess of said second film sheet extending beyond the peripheral edge of said frame around and over said frame, applying heat to the folded, over edge of said second film sheet, shrinking the edge and reducing the perimeter of the film edge below that of the largest perimeter of the frame thereby locking said second film sheet to the frame, shrinking the remainder of the second film sheet to tighten said sheet, thereby enclosing the object between two taut sheets of film which sheets are shrink-locked over opposite sides of a frame which surrounds the object.

6. A method of packaging which comprises placing a first sheet of heat-shrinkable, thermoplastic film over the upper face of a first frame which defines an open area, folding the excess of said first sheet which extends beyond the peripheral edge of said first frame around and under said frame, applying heat to the folded under film edge now positioned against the lower face of the frame thereby shrinking and reducing the perimeter of the film edge below that of the largest perimeter of the frame thereby locking the first film sheet to the frame, placing an object on said first film sheet on the same side as said shrunken edge, placing a second frame similar to the first frame over said shrunken film edge and against the lower face of said first frame thereby concealing said first shrunken edge between said first and second frames, placing a second sheet of heatshrinkable, thermoplastic film over said object and over said second frame, folding the excess of said second sheet which extends beyond the peripheral edge of said second frame over the edge of both frames and against the film-covered upper face of said first frame, applying heat to said second folded-under film edge shrinking and reducing the perimeter of the film edge below that of the largest perimeter of the first frame thereby locking the second film sheet over both frames, then applying heat to the exposed areas of said first and second film sheets to tighten said sheets.

7. A method of packaging which comprises placing a first sheet of heat-shrinkable, thermoplastic film over the open area defined by a rigid frame, said first sheet having an elastic margin about its periphery, said margin having a smaller perimeter than the largest perimeter of said frame, stretching said margin over said frame so as to lock said first sheet to said frame, placing an object against the face of said first sheet, placing a second sheet of heat-shrinkable, thermoplastic film, having an elastic margin around its periphery, said margin having a smaller perimeter than the largest perimeter of said frame over said object and stretching the elastic margin over the frame locking said second sheet to said frame whereby said object is now enclosed between said first and second sheets within the area defined by said frame, and heat-shrinking said first and second sheets to tighten said sheets.

References Cited UNITED STATES PATENTS 2,837,208 6/ 1958 Lingenfelter 206-46 2,993,587 6/1961 Stone et al 20646 X 3,071,906 1/1963 Zebarth et al 5330 3,226,236 12/1965 Weller 5330 X THERON E. CONDON, Primary Examiner E. F. DESMOND, Assistant Examiner

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