Bag Including Easy Open Feature and Method of Construction

Abstract

A bag for containing food products or the like comprises a tubular body section with flanged end seals, having the structural seam creating the tubular body section of the bag positioned along the edge of the bag and incorporated as a tear propagation feature to promote ease of opening and enhanced product access.

Description

FIELD OF THE INVENTION

The present invention relates to food bags that include an easy-open feature and enhanced product access, and which are produced using vertical packaging machinery.

BACKGROUND OF THE INVENTION

Many consumers have difficulty opening plastic food bags due to the strength of the packaging films that are used to construct the bags and/or the strength of the seals featured on the top and bottom of the bag. Most users open plastic food bags by grabbing the bag by each side, then bursting the top seal by pulling outwards on the bag material. In some instances, the bag may be difficult to open due to the strength of the seal or the inability of the user to grab the bag material, an action which can be especially difficult for older adults as well as young children. For these individuals, grasping the sides of a plastic bag may be a difficult task due to limited hand strength. In addition, the bag may burst or tear in an irregular manner or, if it cannot be opened by a manual technique, a cutting device such as a scissors may be required. To address this problem, several techniques have been introduced to provide an opening structure for a bag. Most designs employ a tear feature which incorporates a tear path running parallel to the top transverse seal. Patents including Vaughn (U.S. Pat. No. 8,690,431) and Mobs (U.S. Pat. No. 6,352,364) describe various techniques that are employed to overcome the tear resistance created by the presence of the body seam in the tear path. Other designs include a function wherein a corner portion of the bag is removed to allow access to the contents as shown in Patents Eilert (U.S. Pat. No. 7,971,717) and Edwards (U.S. Pat. No. 8,740,458). While these concepts may assist in opening a bag, they typically provide limited convenience for the user. In consideration of these limitations, the present invention describes a food bag which includes an easy-open tear feature that is convenient for the consumer while also providing enhanced product access.

BRIEF SUMMARY OF THE INVENTION

The invention relates to flexible bags that feature a main body seam that extends from the top of the bag to the bottom of the bag thereby creating the ‘tube’ form of the bag. The invention describes a construction technique for producing a bag of this design wherein the body seam incorporated into the bag during construction is utilized as a tear element to more easily open the bag while also providing enhanced access to the contents. The invention can best be described as being a flexible bag which utilizes the body seam that is created in the production of the tubular body section as a tear strip to more easily open the bag.

Food products including snack foods are often packaged in bags formed from flexible packaging films. These films are formed primarily of plastics such as polypropylene and polyethylene, but can also contain metalized plastic, foil, paper or oriented films. An exemplary film for use when packaging food products is described as being an oriented polymer material that is specially treated to allow long polymeric molecules to align in a given direction, thereby causing the material to preferentially tear in that direction.

Bag construction is accomplished by supplying bag material from a feed roll through a bag making machine wherein the material is wrapped around a forming tube and sealed to itself, thereby producing the tubular body section of the bag. This type of bag construction is typically accomplished on what are known in the industry as vertical form-fill-seal machines. Construction of a bag utilizing these types of machines involves positioning the bag material around a funnel shaped forming tube into which product to be included in the bag is inserted. The bag material is pulled around the outside of the forming tube and one end of the bag material is sealed to the other end of the material, typically through use of a heated sealing bar or other sealing device including ultrasonic, laser seals, cold seal adhesive or other appropriate sealing means. After the body seam is produced, the tubular body section of the bag is sealed at the bottom through a transverse flange seal, the desired product is inserted and the filled bag moves downward off of the forming tube wherein the top transverse flange seal is made. During the action of sealing the top of the first bag, the bottom of the second bag may be simultaneously sealed. The filled and sealed bag is then separated from the bag machine and the same form-fill-seal production sequence continues with the next bag and subsequent bags thereafter. This process produces what is referred to in the industry as a ‘pillow bag’ due to its resemblance to a pillow, and is typically used for packaging snack foods such as potato chips, popcorn or the like.

The vertical body seam typically comprises a double layer seam wherein the bag material is formed into a tube with the ends of the material overlapped onto itself and sealed, an action which produces a flat, non-projecting seam on the body section of the bag. In a second embodiment, the vertical body seam may comprise a flange style seam that could best be described as being a seam produced wherein the inside of one end of the bag material is sealed to the corresponding inside of the other end of the bag material in a manner similar to the transverse top and bottom flange seals. This type of seam will project from the body portion of the bag, or in an additional procedure, the flange could be folded back onto the rear face of the bag and pinned through action of the top and bottom transverse seals. In an additional embodiment, a tubular body seam may comprise a butt seam wherein the ends of the material are bonded together edge to edge therein eliminating any overlap of material. As such, this type of seam will reduce the amount of material required to produce the bag and thereby lower construction costs.

Any type of body seam that would contribute to the action of the opening structure herein described could be incorporated without deviating from the scope of the invention.

When a conventional food bag is assembled, filled and sealed, the body seam for the bag is typically located down the middle of the back side of the bag. A disadvantage to positioning the body seam in the middle of the back side of the bag is that the center position of the seam compromises the print and graphics that could be included on the back side of the bag. In addition, a consumer will need to open the bag from one of the two sealed ends, which typically are the shorter sides of the bag and which therein limit access to the contents.

The present invention repositions the vertical body seam from the middle of the back side of the bag to a position in close proximity to the side edge of the bag, best described as running vertically, or in-line with the bag construction direction, from the end of the top transverse flange seal to the end of the bottom transverse flange seal. In a preferred embodiment, the seam will be located along the side edge of the bag with the overlapped portion or width of the seam located on the back side of the bag to prevent interference with graphics located on the front side. It should be noted that the seam could also be located on the actual edge of the bag with the seam partially or fully visible from the front side of the bag without deviating from the scope of the invention.

In a preferred embodiment, the top and/or bottom transverse flange seals of the bag will include a notch or cut located inboard from the edge of the bag, a distance from the edge of the bag equal to at least the width of the body seam. To open the bag, a user will grasp the top of the bag near the location of the notch and pull the body seam outward and downward, an action which will initiate a tear in the bag material and which will result in the body seam and a portion of the bag material pulling away and separating from the bag. This same tear promoting action could be accomplished to a lesser degree through use of a continuous serrated cut incorporated as the cut used to separate the bags during the production sequence.

The invention describes the vertical body seam becoming in effect, a tear strip to assist in opening the bag. The invention relies on the thickness of the double layered body seam being more tear resistant than the adjacent bag material, thereby allowing the bag material to tear while the body seam remains intact.

In addition to the notch or serrations, an additional tear assistance feature in the form of weakened or ‘scored’ lines or the like may be included without deviating from the scope of the invention. Scored lines are typically created in the outer or ‘face’ layer of the film and not the inner protective barrier layer in order to maintain the integrity of the bag and therein protect the contents.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 Describes a perspective view of a vertical form-fill-seal machine.

FIG. 2 Describes a perspective view of a filled and sealed bag.

FIG. 3 Describes a plan view of the back side of the present invention.

FIG. 4 Describes a plan view of the front side of the present invention.

FIG. 5 Describes a plan view of the front side of the present invention with opening structure partially torn.

FIG. 6 Describes a perspective view of the present invention with the tear strip removed and the bag opened to show access to the contents.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

As included in FIG. 1, bag construction material (10) comprises one or more layers of flexible material and in a preferred embodiment, comprises a tear promoting film such as an oriented polymer material. These oriented materials are specially treated to create long, polymeric molecules which tend to align in a given manner, therein causing the material to tear in a predetermined direction. In a preferred embodiment, the bag material is oriented to allow the material to preferentially tear along the vertical axis of the bag, or more descriptively, parallel to the orientation of the body seam.

In a preferred embodiment, preselected bag material (10) is cut to the desired width and loaded into a bag making machine. FIG. 1 shows an example of a vertical form-fill-seal machine that is commonly used to package snack foods such as chips or the like. This illustration is simplified and does not show the cabinet and support structures that typically surround the machine, but demonstrates the actions of the several elements of the machine. Packaging material (10) is pulled from a roll (11) and passes through tensioners (14) which are included to maintain tautness. The material (10) is wrapped around a hollow, cone shaped product delivery tube (20) which typically features a round or oval cross-section. As the packaging material is pulled downward by drive belts (21), the ends of the film are sealed together along its length by vertical sealer (22) forming body seam (30). The machine then applies a pair of sealing jaws (40) against the tube form of the bag to create transverse seal (50). The product to be packaged is then dropped into the bag through the opening at the top of product delivery tube (20) and is held within the bag above transverse seal (50). The bag then proceeds off of product delivery tube (20) to sealing jaws (40) wherein the top of the bag is sealed through transverse seal (50).

It is important to note and as described in the non-limiting embodiment shown in FIG. 1, sealing jaws (40) are swiveled approximately 90° to position body seam (30) toward the end of sealing jaws (40). This action is incorporated to reposition body seam (30) from the middle of the back panel to a position in close proximity to the ends of top transverse flange seal (50A) and bottom transverse seal (50B). Other construction techniques which would relocate the body seam could be incorporated without deviating from the scope of the invention.

In a preferred embodiment, transverse seal (50) comprises top transverse flange seal (50A) on bag (60) located below the sealing jaws (40) and bottom transverse flange seal (50B) on bag (70) being formed and filled above sealing jaws (40). After transverse seal (50) has been formed, a cut is made across the sealed area dividing transverse seal (50) into top transverse flange seal (50A) and bottom transverse flange seal (50B) therein separating finished bag (60) below transverse seal (50) from partially completed bag (70) above transverse seal (50). Additional bag material (10) is then pulled into the machine to create the next bag in the production sequence.

FIG. 2 describes an assembled, filled and sealed bag of the present invention including tubular body section (12), top transverse flange seal (50A) including notch (75), bottom transverse flange seal (50B) and body seam (30) positioned between the end of the top transverse flange seal (50A) and the end of the bottom transverse flange seal (50B). In a preferred embodiment, the outside edge of body seam (30) will be positioned at or near edge (6) of the bag. Also included and referenced by dotted line is score line (33) featured in the outer layer of the bag construction material and positioned in close proximity to body seam (30).

In an effort to describe the action of the opening structure, FIGS. 3, 4 and 5 present the bag in a flat, plan view configuration, with the back side or back panel of the bag shown in FIG. 3 and correspondingly, the front side or front panel shown in FIGS. 4 and 5. As shown in the art, a line running from the end of top transverse flange seal (50A) to the corresponding end of bottom transverse flange seal (50B) will be considered edge (6) of the bag and which will, in a preferred embodiment, represent the outside edge of body seam (30).

As shown in FIG. 3, the back panel of the present invention includes top transverse flange seal (50A) and bottom transverse flange seal (50B) and vertical body seam (30) which constructs the initial tubular body form of the present invention. Being tube shaped, the back panel is contiguous with the front panel and is defined as being the material between the edge of top transverse flange seal (50A) and the edge of bottom transverse flange seal (50B) and sharing edge (6) with the front panel. Body seam (30) constructs the tube shape of the present invention and runs vertically between the end of top transverse flange seal (50A) and the end of bottom transverse flange seal (50B) and is positioned next to edge (6). In this embodiment, body seam (30) is constructed as an overlapping seam, with inner edge (31) of body seam (30) not visible if viewed from outside the bag but is referred to in the drawing as a dashed line for clarity. The outer edge of body seam (30) could be located along edge (6) of the bag, or body seam (30) could be incorporated as defining edge (6) without deviating from the scope of the invention.

As shown in FIG. 4, the front panel is defined as the body section terminating at the edges of top transverse flange seal (50A) and bottom transverse flange seal (50B) and having edge (6) in common with the back panel. In addition, score line (33) may be included in the front panel, and in a secondary embodiment, in the back panel, to assist in achieving a relatively straight tear when vertical body seam (30) is removed.

As shown in FIGS. 2, 3, and 4, top transverse flange seal (50A) includes notch (75) which is included as a tear initiator. Notch (75) may comprise a variety of shapes including triangular, circular or any other shape including a slit or serrated edge. In the embodiment shown, the tear initiator comprises a V shaped notch (75). Notch (75) may be designed to extend to the edge of top transverse flange seal (50A) or may be designed to retain a small piece of intact material above notch (75) and below the cut edge of top transverse flange seal (50A). This type of notch (75) is designed to prevent the free edges of notch (75) from snagging and thereby opening the package accidentally. Additionally, notch (75) is cut to a limited depth in order to retain the barrier properties created by top transverse flange seal (50A). As shown in FIG. 3, notch (75) will be located next to vertical body seam (30), in close proximity to inside edge (31) of vertical body seam (30), a distance from edge (6) at least the width of body seam (30). This same tear initiation could be accomplished to a lesser degree through use of a serrated cut line created when separating the individual bags in production and which produces top transverse flange seal (50A) and bottom transverse flange seal (50B) on adjacent bags.

In a preferred embodiment, and as best shown in FIGS. 2, 4, and 5, the package further comprises at least one score line (33) positioned between notch (75) and the bottom transverse flange seal (50B) running parallel to body seam (30). As herein described, score lines are intended as an aid in directing the tear to follow a specific path. Score line (33) can be made through various techniques including laser scoring, slitting, or other material weakening technique. Regardless of the type of score incorporated, the barrier properties of the container are retained, a provision which is essential in keeping oxygen and moisture from contacting and adversely affecting the product within the container. In a preferred embodiment, only the outer layer of material is scored with the inner layer remaining intact and the barrier properties of the container retained.

When the outer layer of the material is scored, a line of weakness is created which allows the bag material near notch (75) to tear and propagate along score line (33) from the edge of top transverse flange seal (50A) to bottom transverse flange seal (50B). In a secondary embodiment, additional score lines could be included to enhance tear promotion.

To open the bag, and as best shown in FIG. 5, a consumer will grip the edge of top transverse flange seal (50A) on both sides of notch (75) and pull outward to initiate a tear, then continue to pull outward and downward thereby removing the outer strip of the bag including vertical body seam (30). Because body seam (30) is included in the portion of the bag that is torn away, the inherent strength of body seam (30) will reduce the likelihood that the opening action will tear body seam (30) or will propagate in an uncontrolled direction. This action will be further enhanced with the inclusion of score lines (33) on the front panel and/or back panel of the package.

As shown in FIG. 6, when the tearing action is completed and the tear strip portion of the bag is removed, a consumer will be able to access the contents easily through product access opening (90). Because product access opening (90) is created along the longer side of the bag, greater product access is afforded than is provided when using the flange seal end of a conventional bag.

Although the present invention herein described defines a food product bag, any appropriate non-food product could be included in the package without deviating from the scope of the invention.

Claims

1-12. (canceled)

13) A bag made of tear compliant material and featuring a tear-open strip, said bag constructed using a vertical bag forming machine, said construction comprising the steps of: wrapping bag construction material around the funnel shaped product delivery tube of said vertical bag forming machine, said material overlapped and sealed, forming the vertical main body seam and therein creating the tubular body section of said bag,fabricating a first transverse seal across said tubular body section therein creating a bottom seal, with the terminal end of said first transverse seal being positioned in close proximity to said vertical main body seam,insertion of product to be contained into said bag through said product delivery tube,moving said tubular body section downward and off of said product delivery tube,fabricating a second transverse seal across said tubular body section therein creating a top seal, with the terminal end of said second transverse seal being positioned in close proximity to said vertical main body seam,incorporating a tear initiation feature in the form of a cut or notch into at least one said transverse seal in close proximity to said vertical main body seam,severing and removing said filled and sealed bag from said vertical bag forming machine.

14) The bag of claim 13 wherein said vertical body seam comprises an outward projecting flange seal.

15) The bag of claim 13 wherein said vertical body seam comprises a butt seam having no overlap of material or projecting flange seal.