Quick Opening Container

Abstract

A cylindrical dough can including a body wall formed from two rectangular sheets of approximately equal size bonded together with two pairs of corresponding edges out of alignment so as to form two extensions. The body wall is made into a tube with the extensions bonded together in overlapping relationship along a permanent longitudinally extending seal. Within the body wall is a thin fluid impervious sealing liner, e.g., a foil having a mechanically weak but fluid tight inner seal isolated from the longitudinal seal. A provision such as a tear string is used for severing the outer sheet along a line spaced circumferentially from the overlap area. When pulled, the string penetrates the complete thickness of the outer sheet thereby providing a flap which serves as a pull tab. When the pull tab is lifted, tension is transmitted from the outer extension to the inner extension through the permanent seal thereby separating adjacent cut edges of the inner sheet from one another. The inner seal is then opened.

Description

The present invention relates to packaging products and more particularly to a can which is particularly useful for storing and shipping unbaked refrigerated dough under pressure. The container of this invention is, however, also useful for packaging materials which exert no pressure.

A dough can is described in U.S. Pat. No. 3,214,078 which includes a longitudinally extending lap joint with an adjacent tear tab. Although this container is satisfactory for many applications, the leakage of moisture, oil or gas into the space between the overlapped walls is sometimes a serious problem and the extra thickness of material at the lap joint presents a raw edge which is unsightly. Moreover, the double thickness of the container wall in the overlap area interferes with reliably crimping the metal can ends onto the tubular can body.

Other containers evaluated in the development of the present invention opened with a loud pop or had thin unsupported portions of the liner or label extending beyond the side edges of the body wall when the body material is rolled up upon itself in coil form before being made into a tube. Such extensions can be easily damaged.

It is, therefore, an object of this invention to provide a simply constructed tubular container which includes an effective provision for eliminating the leakage of material into the open space between the overlapped layers of the body wall.

Another object of the invention is the provision of an improved quick opening can for the packaging of refrigerated dough with a longitudinally extending lap joint and a provision which allows the overlapped and sealed area to be reduced in size thereby lessening the tendency for the container to be out of round.

A further object of the invention is the provision of an improved container suited for storing fresh dough and having an opening tab including a longitudinally extending free marginal edge which can be pulled circumferentially to open the container and in which the length of the opening tab can be varied substantially without changing the size of the overlap area between the inner and outer plies of the container.

A further object of the invention is the provision of an improved container of the type described in which the longitudinally extending edges of the liner and label do not project beyond the adjacent edges of the container body wall.

A further object of the invention is the provision of a can for storing material under pressure with a provision that enables the can to be opened without a loud popping noise.

A further object of the invention is the provision of an improved container of the type described in which the body wall of the container is essentially constant in thickness thereby allowing sheet metal discs (can ends) to be reliably crimped to the cut ends of the body wall.

Another object of the invention is the provision of an improved pressure retaining container including a tubular body wall having a longitudinally extending opening tab and a provision that enables the body wall of the container to be withdrawn from the crimped seam of the metal can end when the tab is pulled.

These and other more detailed and specific objects will become apparent from the following description of the invention and drawings wherein:

FIG. 1 is a perspective view of a can embodying the invention.

FIG. 2 is a side elevational view of the container of FIG. 1 with the opening tab partially drawn back.

FIG. 3 is a semi-diagramatic transverse sectional view taken through the stock material used for forming the tubular wall of the container.

FIG. 4 is a transverse sectional view of the container during the last stages of manufacture.

FIG. 5 is a view similar to FIG. 4 after the assembly of the body wall has been completed.

FIG. 6 is a partial longitudinal sectional view of the end of the container.

FIG. 7 is a partial transverse sectional view showing the first stage in opening the container.

FIG. 8 is a view similar to FIG. 7 showing a subsequent stage of opening, and

FIG. 9 is a view similar to FIG. 8 showing a later stage in the opening procedure.

In the accomplishment of the above objectives, the invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

Briefly, the present invention provides a cylindrical can in which the body wall is formed from at least two sheets each having four edges. The sheets are preferably rectangular but any parallelogram is suitable. The two sheets making up the body wall need not have exactly the same shape. The sheets are bonded together with two pairs of their corresponding edges out of alignment. In this way, two generally longitudinally oriented extensions are provided. This composite sheet is formed into a tube with extensions positioned in overlapping relationship and adhered to one another to provide a longitudinally extending bond defining inner and outer butt joints. A provision is made for tearing the outer layer of the body wall longitudinally along a tear line positioned at any point circumferentially of the overlap area within 180.degree. and preferably within 45.degree. of the overlap area. When the outer layer is torn along this line, a pull tab is formed by the longitudinally extending free edge adjacent the tear. When the pull tab is lifted and pulled back toward the overlap area, the force exerted from the outer extension is transmitted to the inner extension through the permanent bond thereby separating the adjacent edges of the inner butt joint from one another and preferably withdrawing the ends of the body wall from their crimped position in the can ends.

The container preferably includes a fluid impervious liner formed from thin sheet material lying adjacent to the inner surface of the body wall of the container. The liner is folded outwardly over edges of the inner sheet that define the inner butt joint and lie adjacent to its outer surface near the longitudinally extending edge thereof. This flap of the liner is bonded to the overlying material of the pull tab so that when the tab is used to open the container, the flap will swing free of the underlying inner sheet material to provide an expansion space for the dough.

The invention will now be described in detail with reference to the figures.

As seen in the figures, the container indicated generally by the numeral 10 comprises a can formed from a tubular body wall 12 and sealed on each end by two identical circular metal end caps 11 and 13. The body wall 12 is formed from flexible sheet material 14 (FIG. 3) composed of a laminate consisting of two relatively thick interior sheets 16 and 18. These sheets may be about 0.014 inches thick and composed of paperboard. Sheets 16 and 18 are suitably bonded to one another by an adhesive 20 which can be applied either in selected areas or, if desired, over the entire contacting surface. As seen in FIG. 3, the sheets 16 and 18 are positioned relative to one another such that their side edges (longitudinally extending edges when formed into a cylinder) are positioned out of alignment so as to provide an internal extension 22 and an external extension 24. The two remaining edges of the body wall 12, i.e., those that fit into the edges of the can ends 11 and 13 are positioned in alignment with one another. Accordingly, it is only the two longitudinally extending edges that are positioned out of alignment with one another to provide the circumferentially projecting inner extension 22 and the circumferentially projecting extension 24.

A liner 26 which is formed from any of a variety of fluid impervious materials such as a laminate composed of aluminum foil bonded to Kraft paper is glued preferably over substantially the entire exposed surface of the inner sheet 18. The liner 26 functions to prevent the penetration of water and grease from the inside of the package into the paperboard layer 18.

A label 28 is preferably bonded to the exterior surface of the sheet 16. If used, the label 28 can be formed from the same material as the liner 26 and is normally printed with the name of the product and directions for its preparation. When no label is used, sheet 16 can be printed.

As best seen in FIGS. 3 and 4, the edges of neither the liner nor label extend beyond the longitudinally disposed edges of the sheets 16 and 18. In the case of the label, its longitudinally disposed edges terminate in alignment with the corresponding edges of the outer sheet 16. The edge of the liner 26 adjacent to the extension 22 is folded outwardly and thence back upon the outer edge of the extension 22 and is securely bonded to it by adhesive at 32 thereby forming a longitudinally extending permanently secured hem 30.

The opposite end of the liner 26 is folded outwardly in a loose manner and back upon the outer surface of the body sheet 18 to provide a free hem 34 which is not bonded or otherwise fastened to the adjacent surface 36 of the inner sheet 18.

Positioned between the sheets 16 and 18, adjacent to the outer terminal extension 24 is a lead-in sheet 40 formed from a fluid impervious material which may be the same as the liner and label. It is securely bonded to sheet 16 by adhesive 42. As shown in FIG. 3, the free edge of the sheet 40 extends slightly beyond the free edge of the inner body sheet 18. The opposite edge of the sheet 40 extends to a longitudinally extending tear means such as tape 44 which is bonded to the sheet 16 by means of adhesive 46. It will be noted that the tear tape 44 is spaced circumferentially a distance from the overlap of the extensions 22 and 24, i.e., it is outside of the overlap area. Spacing between the overlap area and the tear tape 44 can be as great as desired but should not be so short that the fingers of the person opening the can come in contact with the dough as it is expelled from the can at the time the can is opened.

As clearly shown in FIGS. 3, 4 and 5, only the edge of the free hem 34 is bonded by a liquid tight seal 50 (e.g., a hot melt adhesive seal formed by applying molten heat-sealing adhesive to the hem 34) to the overlying lead-in sheet 40. Only the edge of the free hem 34 is adhered to the lead-in sheet 40 for reasons to be described below.

As shown in FIGS. 1 and 2, a C-shaped cut 52 is provided at one end of the tear tape 44 through the label 28 and outer sheet 16 of the core to define a pull tab 54 at the leading edge of the tear tape 44.

The end caps or closures 11 and 13 each consist of a thin metal disc removably crimped by means of seams 56 and 58 to the upper and lower circular edges 15 and 17 respectively of the body wall 12. After the bottom closure 11 has been applied, the biscuits are placed in the container and the top closure 13 is applied and crimped, in other words, seamed, at 58 in a conventional manner to the upper circular edge 15 of the container 10.

As shown in FIGS. 4 and 5 which illustrate successive stages of forming the body wall 12 into a tube, the outer extension 24 is bonded in overlapping relationship to the inner extension 22 by means of a permanent bond 60 of any suitable adhesive adapted to keep the parts permanently bonded together. By "permanent" is meant a bond which will not open when the container is opened. A permanent bond is also made at 62 between the fixed hem 30 and the overlying portion of the lead-in sheet 40. A relatively narrow longitudinally extending peelable bond 50 is made between the edge of the free hem 34 and the overlying lead-in sheet 40. The bond 50 functions to raise the hem 34 when the container is opened. In the last stages of opening the bond 50 peels apart. Thus the bonds 50 and 62 provide a reliable grease and moisture barrier to prevent the escape of material from the container even though the contents are under considerable pressure while the bond 60 provides the requisite strength for preventing separation of the overlapping extensions 22 and 24.

Referring primarily to FIG. 3, a preferred method of fabricating the package will now be described.

The stock used to make the container is assembled in accordance with a preferred manufacturing procedure by bonding the pull tab 44 and the lead-in strip 40 to sheet 16. At the same time, the label 28 is bonded to the outer surface of sheet 16.

The liner 26 is glued to the undersurface of sheet 18 and both the left- and right-hand edges thereof are folded upwardly and centrally over the corresponding edges of sheet 18. The fixed him 30 is then bonded to the outer surface of the extension 22 with the adhesive 32.

The resulting sheets are next glued together by adhesive designated 20. It will be noted that adhesive 20 does not extend at the right to the tear tape 44 (FIG. 3). Accordingly, the portion of sheet 16 and 18 to the right-hand side thereof as seen in FIG. 3 are not bonded together except by the narrow bond 50 between the liner 26 and the overlying lead-in tab 40. Excellent results have been obtained when the bond 50 is formed by heat sealing. In this event, the liner or the lead-in tab are coated with a heat sealing varnish or resin. The bond 50 covers just the edge of the hem 34 as mentioned above. The completed contour body 12 consists of a sheet which is shown in transverse cross section in FIG. 3. It is normally rolled up upon itself to form a large coil or storage roll before being cut and formed into a tube.

The body wall 12 can be formed into a tube in any suitable known manner as described, for example, in U.S. Pat. Nos. 3,213,890 and 3,139,012. The last stage of the tubing operation is shown in FIG. 4. At the stage shown in FIG. 4, the extension 24 is drawn toward and placed in overlapping relationship with extension 22. The longitudinally extending band of adhesive 60 securely bonds the adjacent flaps together and provides a permanent connection between them. When the edges of the tube are brought together, an external longitudinal butt joint 80 and internal longitudinal butt joint 82 are formed.

The bond 62 is preferably formed at the same time as bond 60. The bond 62 is preferably formed by heat sealing (in which event either the inward surface of the lead-in tab 40 or the adjacent surface of the liner 26 is covered with a heat sealing varnish or other thermoplastic resin) or by extruding a hot melt adhesive into the seam.

After the tube has been made and cut transversely at 15 and 17, the circular metal end or bottom closure 13 is applied by removably crimping its edges onto the adjacent end 17 of the container body 12. By "removably" is meant that the edges of the body wall are capable of being removed (i.e., withdrawn) without being torn apart when the container is opened and the tab 86 is pulled.

After the bottom closure 13 has been applied, the contents of the package, e.g., pieces of biscuit dough 84 (FIG. 2), are inserted. The dough normally contains a leavening material such as an acid and a base in sufficient quantity to maintain the dough within the container under pressure during its normal storage period.

The lid 11 is placed on the top of the container and its edges removably crimped to the edge 15 of the container body 12.

The manner in which the package is opened will now be described with particular reference to FIGS. 1, 2, 7, 8 and 9.

The tear tape 44 is first pulled from left to right as seen in FIGS. 1, 2, 7, 8 and 9 by grasping the extension 54. Pulling the tape 44 produces a longitudinally extending opening tab 86 which the user then grasps with his fingers and pulls upwardly as seen in FIG. 2. At the tab 86 is pulled open (toward the right as seen in FIG. 5), the opening force is transmitted to the sheet 18 by means of the permanent bond 60 and to some extent by the bond 62.

It should be noted that as the tab 86 is lifted, the unattached portion of the free hem 34 pivots outwardly as a free swinging panel since it is not adhered to the underlying body sheet 18. As this is done, the pressurized dough is expelled through the opening between the butt joint 82 into an expansion area 88. In this way, the pressure of the dough is relieved without causing the container to pop when opened.

Continued movement of the pull tab 86 toward the right as seen in FIGS. 7, 8 and 9 will cause the liquid tight seal 50 to be broken. Further movement of the tab 86 will slide the cut ends 15 and 17 of the fiber body wall 12 from their tightly engaged position within the seams 56 and 58. Because the thickness of the body wall is approximately the same at all points around the circumference of the container, the force required to withdraw the body wall from the seams 56 and 58 is constant. Accordingly, the tube 12 can be easily capped and readily opened.

The invention has a number of important advantages. The container can be readily opened without the occurrence of a loud, objectionable pop, and it is relatively easy to make a wide opening in the container since the cut ends 15 and 17 slide out of the seams 56 and 58. This allows those biscuits adjacent the metal discs 11 and 13 to be readily removed.

It will also be seen that the liquid tight seals 50 and 62 prevent the leakage of moisture, gas and oil in the interior of the container through the butt joint 82 into the area between the sheets of material from which the container wall is formed. Moreover, no unsightly raw edge of the material exists at the lap joint.

A further advantage of the invention is the elimination of laterally extending unsupported portions of the liner or label which, if present, can be easily damaged when the raw material for the container body is stored in roll form.

A further advantage of the invention is the reduction in the width of the overlap area. This is desirable because it tends to make the container more exactly circular.

It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from the spirit and scope thereof. The specific embodiments described are given by way of example only and the invention is limited only by the terms of the appended claims.

Claims

We claim:

1. A pressure-retaining tubular container comprising a substantially cylindrical core formed from at least a pair of sheets of material each having four edges, said sheets being bonded together with two pairs of their corresponding edges out of alignment to provide a pair of longitudinally oriented extensions, said core being formed into a tube with the extensions positioned in overlapping relationship thereby defining outer and inner butt joints extending between the ends of the cylindrical core, a permanent bond between the overlapping extensions, an end closure member affixed to at least one end of the tube, a means for tearing the outer sheet of the core along a line extending longitudinally of the container outside of the overlapped area closer to the inner butt joint than the outer butt joint, the outermost extension defining a pull tab from the material of the outer sheet between the tear means and the overlap area which when lifted and pulled toward the overlap area transmits forces from the pull tab through the permanent bond to the inner sheet so as to separate the adjacent edges of the inner butt joint from one another and thereby open the container, a piece of sheet material extends circumferentially from the inner butt joint over the outer surface of the inner sheet, at least the free marginal edge thereof is removably adhered to the overlying surface of the outer sheet and the opposite edge thereof is connected to the adjacent longitudinally extending edge of the underlying sheet, whereby a free swinging panel is defined to provide a space to receive the expanding dough as the package is opened.

2. The container of claim 1 wherein, said piece of sheet material is a liner adhered to substantially the entire inner surface of the core, one edge of the liner being folded outwardly over a longitudinally extending edge of the inner sheet and bonded to the outer surface thereof to form a fixed hem and the opposite edge of the liner is folded outwardly over the outer surface of the liner and its free marginal edge portion is bonded to the overlying surface of the outer sheet.

3. A container according to claim 2 wherein the bond between said free edge of the liner and the outer sheet is formed with a heat sealing adhesive.

4. The container according to claim 2 wherein the bond between the fixed hem and an overlying portion of said core is formed from a heat sealing adhesive.

5. The container according to claim 1 wherein a lead-in sheet formed from a fluid impervious sheet material is bonded to the inner surface of the outer sheet in the area between the overlap of the extensions and the tear means and a liner formed from sheet material is bonded to the inner surface of the inner sheet and is folded outwardly over the adjacent edges of the inner butt joint and is bonded to the overlying portion of the lead-in sheet to prevent the leakage of fluids from the container.

6. The container according to claim 1 wherein the overlap area extends parallel to the longitudinal axis of the cylinder.

7. The container according to claim 1 wherein the tear means comprises a tear tape bonded to the inside surface of the outer sheet.

8. The container according to claim 1 wherein a pair of circular end closure members are removably crimped to the ends of the tube whereby the pulling of the pull tab outwardly will cause the edges that are crimped into the end closure members to be withdrawn from the closure members as the container is opened to permit the container to be opened.

9. A can comprising a tubular body wall, at least one end closure member affixed to one end of the body wall to provide a bottom for the container, said body wall being formed from at least a pair of sheets each having four edges and being bonded together over at least a portion of their contacting surfaces and having overlapping extensions defining nonaligned outer and inner longitudinally extending butt joints, a tear means for serving at least the outermost of the sheets to define a lifting tab, a lead-in barrier material bonded to the inner surface of the sheet that is severed when the tear means is utilized, a liner formed from fluid impervious material bonded to the inner surface of the container and having a fixed hem composed of a section folded outwardly through the inner butt joint and back upon the underlying sheet and bonded to the underlying sheet material of the body wall, and a bond between the outer surface of the fixed hem and the overlying lead-in material, pulling a force exerted upon the lifting tab toward the inner butt joint will be transmitted through the bond between the fixed hem and the lead-in sheet to the underlying portion of the container body thereby separating the adjacent parts of the inner butt joint from one another, said bond between the lead-in sheet and the fixed hem preventing the leakage of fluid from the container.

10. The container according to claim 9, wherein the opposite end of the liner is also folded outwardly through the inner butt joint area and back upon itself to define a second hem, at least a portion of the outer surface of the second hem being also bonded to the overlying lead-in sheet to provide a substantially fluid-tight seal for preventing the loss of materials from the container.

11. The container according to claim 9 wherein a pair of circular end closure members are removably crimped to the ends of the tube whereby the pulling of the lifting tab outwardly will cause the edges that are crimped into the end closure members to be withdrawn from the closure members as the container is opened to permit the container to be opened in the area of the end closure members.

12. A pressure-retaining container for materials under pressure comprising a tubular body wall, at least one end closure member affixed to the end of the tube to form a bottom for the container and said body wall having a line of separation extending from one end of the container to the other for opening the container, said body wall including in at least part of its circumference a pair of overlapping sheets, a free-swinging panel connected between the overlapping sheets and being secured to the innermost of the two sheets at a point adjacent to the line of separation and extending circumferentially therefrom between said sheets and having its end furthest removed from the line of separation secured to the outer of the two sheets to provide a free-swinging panel, lifting of the outermost of the overlapping sheets and pulling outwardly thereupon will cause the panel to swing away from the innermost sheet to provide an expansion space into which the compressed material is free to expand as the tab is pulled to prevent the container from popping when opened.