This invention generally relates to reclosable bags having features that provide evidence of tampering. In particular, the invention relates to reclosable bags having a hood that shrouds or covers the zipper and must be breached in order to access the zipper.
Reclosable bags are finding ever-growing acceptance as primary packaging, particularly as packaging for foodstuffs such as cereal, fresh fruit and vegetables, cold cuts, snacks and the like. Such bags provide the consumer with the ability to readily store, in a closed, if not sealed, package any unused portion of the packaged product even after the package is initially opened.
Reclosable bags comprise a receptacle having a mouth with a plastic zipper for opening and closing. Typically, a zipper for a reclosable bag includes a pair of interlockable profiled closure strips that are joined at opposite ends of the bag mouth. The profiles of interlockable plastic zipper strips can take on various configurations, e.g. interlocking rib and groove elements having so-called male and female profiles, interlocking alternating hook-shaped closure elements, etc.
Various additions to reclosable bags have been made to provide tamper-evident seals or indicators that will reveal when the bag has been opened or otherwise tampered with prior to purchase by the consumer. It is known to provide a reclosable package construction that is designed to undergo some permanent change in the package appearance when the package is opened for the first time. For example, it is known to provide a reclosable package with a tamper-evident, non-reclosable peel seal that gives a positive indication of having been broken when a package is first opened. It is also known to shroud the zipper inside an enclosed header on the top of the bag. Another type of tamper-evident feature is the provision of a membrane on the product side of the zipper that partitions the interior volume in an airtight manner.
In the formation of reclosable plastic bags when the bags are used for foodstuffs and like material, it is advantageous to have the bags supplied with a tamper-evident seal which not only protects the contents from the ingress of foreign materials and contamination, but also shows if inadvertent or intentional opening has occurred prior to the bag and its contents being in the possession of the buyer. Such a protective seal if formed continuous externally of the reclosable seal rather than internally, can additionally protect the reclosable zipper elements from dust and dirt and other contaminants with a permanent protective seal located outwardly of the reclosable seal, moisture and other foreign elements cannot enter the bag and the purchaser can see that he is obtaining a previously unopened and unused bag where the contents are fully protected. This conveys a feeling of safety and comfort to the purchaser who may be concerned about someone criminally obtaining access to the bag and placing dangerous contaminants into the contents.
There is a continuing need for new designs for reclosable bags with tamper-evident features for hermetic and non-hermetic packages that can be manufactured at low cost.
The present invention is directed to methods of manufacturing reclosable bags having a hooded zipper. The invention is further directed to the structure of certain reclosable bags having a wicket flap at one end and a hooded zipper at the other end.
One aspect of the invention is a method of manufacturing a reclosable bag, comprising the following steps: (a) slitting a web of bag making film along a line, thereby severing a first portion of the web from a second portion of the web; (b) orienting the first and second web portions to be mutually confronting; (c) joining a first side of a hood of a hooded zipper to the first web portion along a first band-shaped zone, the hood having a generally U- or V-shaped profile; (d) joining a second side of the hood to the second web portion along a second band-shaped zone; (e) cross sealing the first web portion to the second web portion and the first side of the hood to the second side of the hood along first and second lines that are parallel to each other and transverse to the hooded zipper, the first and second lines being disposed at first and second locations respectively; and (f) cutting the first and second web portions and the hooded zipper at the first and second lines, thereby forming an individual bag.
Another aspect of the invention is a reclosable bag comprising: a receptacle comprising mutually confronting first and second walls that are joined at the sides, the first wall comprising a portion that forms one side of a mouth at a first end of the receptacle and the second wall comprising a portion that forms another side of the mouth; a hooded zipper comprising first and second mutually interlockable profiled fastener means respectively joined or connected to mutually confronting portions of a folded web, the mutually confronting portions of the folded web in turn being joined to the portions of the first and second walls respectively; and a flap extending from a second end of the receptacle in a direction away from the mouth, the second end being opposite to the first end.
A further aspect of the invention is a method of manufacturing a reclosable bag, comprising the following steps: (a) folding a web of bag making film; (b) slitting the web along the fold to form first and second edges of first and second web portions respectively; (c) joining a first side of a hood of a hooded zipper to the first web portion along a first band-shaped zone near the first edge, the hood having a generally U- or V-shaped profile; (d) joining a second side of the hood to the second web portion along a second band-shaped zone near the second edge; (e) cross sealing the first web portion to the second web portion and the first side of the hood to the second side of the hood along first and second lines that are parallel to each other and transverse to the hooded zipper, the first and second lines being disposed at first and second locations respectively; and (f) cutting the first and second web portions and the hooded zipper at the first and second lines, thereby forming an individual bag.
Yet another aspect of the invention is a method of manufacturing a reclosable bag, comprising the following steps: (a) slitting a web of bag making film along a slit line to form first and second edges of first and second web portions respectively; (b) orienting the first and second web portions to confront each other in respective generally vertical positions; (c) joining a first side of a hood of a hooded zipper to the generally vertical first web portion along a first band-shaped zone near the first edge, the hood having a generally U- or V-shaped profile; (d) joining a second side of the hood to the generally vertical second web portion along a second band-shaped zone near the second edge; (e) cross sealing the first web portion to the second web portion and the first side of the hood to the second side of the hood along first and second lines that are parallel to each other and transverse to the hooded zipper, the first and second lines being disposed at first and second locations respectively; and (f) culling the first and second web portions and the hooded zipper at the first and second lines, thereby forming an individual bag.
A further aspect of the invention is a method of manufacturing a reclosable bag, comprising the following steps: (a) slitting a web of bag making film having mutually parallel first and second edges along a line that is generally parallel to the first and second edges, thereby severing a first portion of the web from a second portion of the web, the first web portion having the first edge and a third edge generally parallel to the first edge, and the second web portion having the second edge and a fourth edge generally parallel to the second edge; (b) orienting the first and second web portions to be mutually confronting; (c) joining a first side of a hood of a hooded zipper to the first web portion along a first band-shaped zone disposed near one of the first and third edges, the hood having a generally U- or V-shaped profile; (d) joining a second side of the hood to the second web portion along a second band-shaped zone disposed near one of the second and fourth edges; (e) cross sealing the first web portion to the second web portion and the first side of the hood to the second side of the hood along first and second lines that are parallel to each other and transverse to the hooded zipper, the first and second lines being disposed at first and second locations respectively; and (f) cutting the first and second web portions and the hooded zipper at the first and second lines, thereby forming an individual bag.
Yet another aspect of the invention is a reclosable bag comprising: (a) a receptacle comprising mutually confronting first and second walls that are joined at the sides, the first wall comprising a portion that forms one side of a mouth at a first end of the receptacle and the second wall comprising a portion that forms another side of the mouth; (b) a hooded zipper comprising first and second mutually interlockable profiled fastener means respectively joined or connected to mutually confronting portions of a folded web comprising a line of perforations disposed off center, the mutually confronting portions of the folded web in turn being joined to the aforementioned portions of the first and second walls respectively, and a folded portion of the folded web connecting the mutually confronting portions of the folded web being disposed away from the mouth; and (c) a band of material that covers and seals the perforations in the folded web.
Other aspects of the invention are disclosed and claimed below.
Reference will now be made to the drawings in which similar elements in different drawings bear the same reference numerals.
A reclosable package in accordance with one embodiment of the invention is shown in
The walls 2a and 2b are heat sealed to each other along the sides of the receptacle. The package depicted in
The hooded zipper 4 comprises a web 5 and a pair of interengageable zipper profiles 6 and 8, seen in
To gain access to the contents of the filled package, the user must first tear off the top of the hood and then open the zipper to gain access to the interior volume of the receptacle. To facilitate tearing off the top portion of the hood, the web 5 is provided with a pair of lines of spaced perforations running the length of the membrane and parallel to the zipper profiles 6, 8. When the web 5 is flat, the perforated lines are disposed between the zipper profiles. Furthermore, in accordance with one embodiment, each line of perforations is capped by a respective sealing stripe 11 (see
After the flat web has been perforated and the perforations have been sealed, the web/zipper extrusion or assembly is folded in a central region (e.g., along a midline of web 4) so that the zipper profiles are brought into alignment with each other, i.e., the fold line is parallel to the zipper profiles. [The lines of perforations 10 are disposed on the web 5 to be at approximately the same elevation when the web 5 is folded.] Then the aligned zipper profiles 6, 8 are interlocked to close the zipper. As seen in
In accordance with one embodiment of the hooded zipper 4 shown in
Packages of the type depicted in
During the next stage of manufacture, a section of a continuous length of hooded zipper tape 4 is guided into a position whereby the respective marginal portions of the web 5 (below the zipper profiles) are inserted between (i.e., inside) the respective marginal web portions adjacent the edges formed by the slit, as seen in
The remaining stages of the first method of manufacture are conventional and not shown in the drawings. After each section of continuous hooded zipper tape 4 has been attached to respective sections of web portions 2a and 2b, as depicted in
Various stages of a second method of manufacturing the package depicted in
During the next stage of manufacture depicted in
After attachment of the hooded zipper to the folded web 2, the web 2 is slit, along a line that is offset from the centerline of the web, by a cutting device 24, such as a knife or other blade. An exemplary location for the slit is indicated by the location of cutting device 24 in
In accordance with an alternative to the first method of manufacture, the marginal portions of the web 5 of a hooded zipper are placed outside the marginal portions of web portions 2a and 2b after the web has been slit and prior to joining the web portions to the sides of the hooded zipper, as depicted in
In accordance with an alternative to the second method of manufacture (not shown in the drawings), the marginal portions of at web of a hooded zipper are placed outside the marginal portions of a folded web prior to joining the web portions to the sides of the hooded zipper and prior to slitting the web of packaging film.
In accordance with further alternative methods of manufacture, instead of using a separating plate to prevent seal-through during the heat sealing operation, the confronting surfaces of the innermost web portions can be coated with layers of non-sealant material, i.e., material that will not soften or melt during the heat sealing operation. For example, for the cases depicted in
The embodiments disclosed above each have a wicket flap. However, another aspect of the invention is the manufacture of packages having hooded zippers and not having a wicket flap. This can be accomplished by slitting the web along its centerline instead of along a line offset from the centerline. A sectional view of such a package (open at the bottom) is shown in
The system described in the preceding paragraph can be used to make pouches for filling later. Alternatively, a chain of pouches, open at one end and with a hooded zipper at the other end, can be fed directly into a form-fill-seal machine. Upstream of the cross-sealing jaws, the web can be advanced either continuously or intermittently. Cross sealing is typically performed during dwell times.
Downstream of the blade 36, the web portion 2a is folded or turned to a vertical orientation relative by a folding plow or board 38 and a vertical guide bar 32. In this configuration, web portion 2b remains horizontal and web portion 2a is accessible for attachment of a zipper tape 4 of the type previously described. Zipper tape 4 is supplied from a spool 40. A guide 42 is positioned and configured to direct the zipper tape 4 to extend along the lower margin of web portion 2a, which will result in a bag that will be filled through its bottom. Downstream of guide 42, the zipper tape 4 is disposed between the lower margin of web portion 2a and a backing plate 44. Then a reciprocating heated sealing bar 46, while in an extended position, joins a length of zipper tape 4 to an equal length of the lower margin of web portion 2a by conventional conductive heat sealing.
Up to this point in this particular implementation, the web portion 2b has traveled in a horizontal path. Downstream of the heating sealing bar 46, however, web portion 2b passes under a roller 48 and along a folding plow or board 50 and a vertical guide 52, which fold or turn web portion 2b to a vertical orientation, causing the inside surfaces of web portions 2a and 2b to confront each other. The web portions 2a and 2b are then advanced to a reciprocating heated sealing bar 54, which seals a length of the lower margin of second web portion 2b to a corresponding length of zipper tape 4 against a backing plate 62. Then the web portions 2a and 2b with the zipper tape 4 joined thereto are advanced to a location between a pair of mutually opposing reciprocating vertical sealing bars 56 and 58 that are extended to engage the web portions 2a and 2b and form vertical side seals 60. At least one of the sealing bars 56 and 58 is heated.
Following the formation of the side seals 60, the web portions 2a and 2b with zipper tape 4 joined thereto are advanced to a cutting and filling portion of the machine (not shown in the drawings). This cutting and filling portion of the machine may take many different forms. Two embodiments are shown in
In accordance with one embodiment of the cutting and filling portion of the machine shown in
Alternatively, the unsealed end of each bag precursor is opened by vacuum devices, filled with product, and then sealed by a pair of horizontal sealing bars 74 (shown in
In accordance with some embodiments of the invention, the wicket flap is integrally formed with either the front or rear wall of the receptacle. However, the bag shown in
While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for members thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the invention without departing from the essential scope thereof. Therefore it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
As used in the claims, the verb “joined” means fused, bonded, sealed, adhered, etc., whether by application of heat and/or pressure, application of ultrasonic energy, application of a layer of adhesive material or bonding agent, interposition of an adhesive or bonding strip, etc. As used in the claims, the term “package” includes bags, pouches, and any other type of packaging (filled or empty) in which a flexible plastic zipper can be incorporated. Further, in the absence of explicit language in any method claim setting forth the order in which certain steps should be performed, the method claims should not be construed to require that steps be performed in the order in which they are recited.