Patent Application
20060257054
This invention generally relates to reclosable bags. In particular, the invention relates to evacuable reclosable storage bags (the terms “evacuable storage bag” and “vacuum storage bag” will be used interchangeably hereinafter).
Collapsible, evacuable storage bags typically include a flexible, airtight receptacle having a mouth through which an article or goods can be inserted, an extruded plastic zipper for closing the mouth and hermetically sealing the receptacle, and a fixture (such as a one-way valve) through which excess air is evacuated from the bag. A user opens the zipper, places an article or goods into the open receptacle, closes the zipper, thereby hermetically sealing the receptacle, and then evacuates the air in the receptacle through the fixture. With the storage bag thus evacuated, a compressible article contained therein may be significantly compressed so that it is easier to transport and requires substantially less storage space.
Collapsible, evacuable storage bags are beneficial for reasons in addition to those associated with compression of the stored article. For example, removal of the air from the storage bag inhibits the growth of destructive organisms, such as moths, silverfish, and bacteria, which require oxygen to survive and propagate. Moreover, such bags, being impervious to moisture, inhibit the growth of mildew.
Not only large, compressible items such as clothing may be stored in collapsible, evacuable storage bags. For example, it may be desirable to store bulk items made of small particles, such as powders or granulated resins, in an evacuated bag. One situation that commonly occurs is that a particular bulk item is shipped in a large, rigid bag such as a drum. Bulk items may be moisture sensitive and are sealed against moisture during shipment. But many times a user does not need to use the entire contents of the large bag, and so once exposed to air the remaining bulk contents quickly become unusable and are thus wasted.
There is a continuing need for improvements in flexible, evacuable, reclosable storage bags.
The present invention is directed to storage bags having two or more evacuable reclosable compartments. Each compartment can be opened (to allow an article or goods to be placed inside), hermetically sealed, and then evacuated without disturbing the vacuum in the other compartment(s). Each compartment comprises a respective zipper that provides a hermetic seal and a respective valve through which air is exhausted from the compartment interior. The bag can be provided with means for hanging in a closet. Alternatively, the bag can be folded for storage in a drawer or other container. A two-compartment bag can be provided with a handle in the center for travel and carry-on and can be used like saddlebags. The present invention is further directed to methods of manufacturing the storage bags disclosed herein.
One aspect of the invention is a storage bag comprising a first receptacle having an interior volume and a mouth, a first zipper that hermetically seals the mouth of the first receptacle when the first zipper closed, a second receptacle having an interior volume and a mouth, and a second zipper that hermetically seals the mouth of the second receptacle when the second zipper closed, wherein the first and second receptacles are connected, and the first and second zippers are disposed at opposite ends of the storage bag when the storage bag is arranged such that the first and second receptacles lie in the same plane with no fold therebetween, further comprising configurable means for exhausting air out of the first and second receptacles, the air exhausting means having a first configuration wherein air can be exhausted out of the first receptacle without affecting the amount of air in the second receptacle and having a second configuration wherein air can be exhausted out of the second receptacle without affecting the amount of air in the first receptacle.
Another aspect of the invention is a storage bag comprising first and second reclosable, evacuable compartments connected along a common side, wherein: the first compartment comprises a first receptacle having an interior volume and a mouth, a first zipper that hermetically seals the mouth of the first receptacle when the first zipper closed, and a first one-way valve for evacuating the interior volume of the first receptacle when the first zipper is closed; the second compartment comprises a second receptacle having an interior volume and a mouth, a second zipper that hermetically seals the mouth of the second receptacle when the second zipper closed, and a second one-way valve for evacuating the interior volume of the second receptacle when the second zipper is closed; and the common side comprises a band-shaped hermetic cross seal that prevents air inside the interior volume of one of the first and second receptacles from entering the interior volume of the other of the first and second receptacles.
A further aspect of the invention is a storage bag comprising first and second reclosable, evacuable compartments connected by an intermediate structure, wherein: the first compartment comprises a first receptacle having an interior volume and a mouth, and a first zipper that hermetically seals the mouth of the first receptacle when the first zipper closed; the second compartment comprises a second receptacle having an interior volume and a mouth, and a second zipper that hermetically seals the mouth of the second receptacle when the second zipper closed; and the intermediate structure comprises a valve outlet, a first collapsible valve that allows flow communication between the interior volume of the first receptacle and the valve outlet when the first collapsible valve is not collapsed, and a second collapsible valve that allows flow communication between the interior volume of the second receptacle and the valve outlet when the second collapsible valve is not collapsed.
Yet another aspect of the invention is a method of manufacture comprising the following steps: (a) arranging first and second webs of bag making material, first and second zipper tapes, and first and second valves strip such that the first and second webs of bag making material are in overlapping relationship with the first and second zipper tapes and the first and second valve strips arranged in parallel therebetween, with the second valve strip overlapping the first valve strip and the overlapping first and second valve strips being between the first and second zipper tapes, wherein the first zipper tape comprises a first pair of interlocked zipper strips and the second zipper tape comprises a second pair of interlocked zipper strips; (b) joining one zipper strip of each of the first and second zipper tapes to the first web and joining the other zipper strip of each of the first and second zipper tapes to the second web, the zipper strips being joined along their full length; (c) in first and second band-shaped zones of joinder that each extend from the first zipper tape to the second zipper tape, joining the first and second webs to each other in sections where the valve strips are absent and joining the first and second webs and the first and second valve strips together in sections where the valve strips are present; (d) joining the first and second webs and the first and second valve strips together in third through sixth band-shaped zones of joinder that each extend along a major portion of the distance separating the first and second band-shaped zones of joinder; (e) joining the first web to the first valve strip in seventh and eighth band-shaped zones of joinder that each extend along a minor portion of the distance separating the first and second band-shaped zones of joinder; and (f) joining the second web to the second valve strip in ninth and tenth band-shaped zones of joinder that each extend along a minor portion of the distance separating the first and second band-shaped zones of joinder. After steps (a) through (f) have been fully performed, the following structural relationships exist: (i) the third and sixth band-shaped zones of joinder are contiguous with the first band-shaped zone of joinder and extend toward, but do not meet the second band-shaped zone of joinder; (ii) the fourth and fifth band-shaped zones of joinder are contiguous with the second band-shaped zone of joinder and extend toward but do not meet the first band-shaped zone of joinder; (iii) the ninth band-shaped zone of joinder overlaps the seventh band-shaped zone of joinder, and the tenth band-shaped zone of joinder overlaps the eighth band-shaped zone of joinder (iv) the seventh and ninth band-shaped zones of joinder are contiguous with the second and third band-shaped zones of joinder; and collinear with the third band-shaped zone of joinder such that the first web is joined to the first valve strip and the second web is joined to the second valve strip along a first line that extends from the first band-shaped zone of joinder to the second band-shaped zone of joinder; and (v) the eighth and tenth band-shaped zones of joinder are contiguous with the second and sixth band-shaped zones of joinder; and collinear with the sixth band-shaped zone of joinder such that the first web is joined to the first valve strip and the second web is joined to the second valve strip along a second line that extends from the first band-shaped zone of joinder to the second band-shaped zone of joinder.
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.
One wall of bag 4 has a hole (not shown in
During use, one or more discrete articles or a bulk material (not shown) may be placed inside the bag 4 while the zipper 8 is open, i.e., while the closure profiles of the interlockable zipper strips are disengaged from each other. After the article or material to be stored has been placed inside the bag, the mouth of the bag 4 can be sealed by pressing the zipper strips together to cause their respective closure profiles to interlock with each other. The zipper strips can be pressed together using a device 10 commonly referred to as a “slider” or “clip”, which straddles the zipper. The typical slider has a generally U-shaped profile, with respective legs disposed on opposing sides of the zipper. The gap between the slider legs is small enough that the zipper can pass through the slider gap only if the zipper is in a closed state. Thus when the slider is moved along an open zipper, this has the effect of pressing the incoming sections of the zipper strips together. The zipper is opened by pulling apart the zipper upper flanges, as explained in more detail below. The slider can be made using any desired method, such as injection molding. The slider can be molded from any suitable plastic, such as nylon, polypropylene, polystyrene, acetal, polyketone, polybutylene terephthalate, high-density polyethylene, polycarbonate, or ABS.
The zipper 8 comprises a pair of mutually interlockable zipper strips made of extruded thermoplastic material, each zipper strip having a respective generally constant profile along the interlockable portion of the zipper. The ends of the zipper strips are joined together at the sides of the bag, e.g., by the application of heat and pressure, which typically involves crushing of the zipper profiles. The zipper 8 is designed to form a hermetic seal at the mouth of the bag 4 when the zipper 8 closed. After the zipper has been closed, the interior volume of the bag can be evacuated by sucking air out via the one-way valve assembly 6. Air can be drawn out of bag 4 through valve assembly 6 using a conventional vacuum source, such as a household or industrial vacuum cleaner. The valve assembly 6 and the zipper 8 maintain the vacuum inside bag 4 after the vacuum source is removed.
The various embodiments of the invention improve upon the type of bag shown in
In accordance with one embodiment of the present invention, two evacuable compartments are connected at their bottoms in saddlebag fashion to form a two-compartment storage bag.
The fourth side of compartment 12 has a zipper 8a installed at one end of the two-compartment bag between marginal portions of the front and rear bag walls, while the fourth side of compartment 14 has a zipper 8b installed at the other end of the two-compartment bag between marginal portions of the front and rear bag walls. These marginal portions of the front and rear walls are respectively sealed to the zipper strips by lengthwise conduction heat sealing in conventional manner. Alternatively, the interlockable zipper strips can be attached to the wall panels by adhesive or bonding strips or the zipper profiles can be extruded integrally with the bag material.
Zippers 8a and 8b are identical in construction and preferably have interlockable closure profiles that form a hermetic seal when interlocked. Instead of designing the closure profiles of the zipper to form a hermetic seal when interlocked, alternative means (e.g., a layer of pressure sensitive adhesive material or two layers of cohesive material) for hermetically sealing the interface between the interlocked zipper strips may be provided on the zipper.
A person may store goods in either compartment of the storage bag depicted in
One type of zipper suitable for use in the two-compartment bag seen in
Still referring to
A known slider or clip suitable for use in the two-compartment storage bag shown in
A known valve assembly suitable for use in the two-compartment storage bag shown in
The two-compartment storage bag shown in
The second web of bag making material is paid out from a second supply roll and advanced in a machine direction, the paid-out section being under tension and disposed in a plane. The first second web also has mutually parallel lateral edges. Circular holes are punched in the paid-out sections of the second web, the holes being located where the valve assemblies are to be installed. More specifically, two holes are punched in each of a succession of contiguous sections of the second web, each section having a length equal to the width of the bag shown in
At the same time that the second web is being joined to the zipper tapes (which are in turn already joined to the first web), the second web is being joined to the first web in a central band-shaped zone whose centerline is substantially collinear with the midline of the first web. At any moment in time during machine operation, this central zone of joinder extends along the full length of the portions of the paid-out sections of the first and second webs that are disposed downstream of the sealing station that forms the central zone of joinder.
After both webs have been joined to both zipper tapes, the zipper tapes are thermally crushed or ultrasonically stomped at regular spaced intervals therealong to form joints where zipper strips of the same zipper tape are joined; the first and second webs are cross sealed in transverse band-shaped zones of joinder disposed at regular spaced intervals therealong such that the web cross seals are substantially aligned with the zipper joints; and sliders are inserted at regular spaced intervals along both zipper tapes. Alternatively, the zipper joints can be made before the zipper tapes are attached to the first web or after they have been attached to the first web but before the second web is joined to the zipper tapes. A person skilled in the art will appreciate that the zipper strips could be joined to the respective webs separately and then interlocked when the webs are placed in overlying relationship with the zipper strips of each pair respectively aligned with each other.
Following the completion of all of the foregoing method steps, the work in process consists of a chain of paired compartments, each compartment having a respective section of zipper tape, a respective slider and a respective valve assembly. Typically the webs and the zipper tapes are advanced intermittently, while the operations described above are performed during the dwell times.
At a cutting station, individual two-compartment bags are severed from one another by cutting along a line that bisects each successive cross seal, thereby forming respective side seams on the separated two-compartment bag and the leading two-compartment bag still attached to the work in process. Each severed two-compartment bag comprises a pair of overlapping rectangular sheets of flexible bag making material of a type previously described with reference to the known vacuum bag shown in
In order to make a succession of two-compartment bags, the cross sealing station operates during each dwell time, as does the cutting station. However, the automated production line can be altered to produce four-compartment, six-compartment, eight-compartment, etc. bags by controlling the cutting station to respectively operate only once every two work cycles, three work cycles, four work cycles and so forth.
A two-compartment storage bag in accordance with a second embodiment of the invention is depicted in
As best seen in
Referring to
Still referring to
Similarly, the short band-shaped zone 76 (indicated by dashed lines in
The flow path for exhausting air from the interior volume of compartment 14′ is represented by arrows A-C in
As disclosed in U.S. Pat. No. 6,729,473, the valve strips are preferably made of a material that is smoother than the bag wall material. Such materials include, but are not limited to, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) or polyethylene/EVOH/polyethylene. The valve strips preferably each have a thickness of 2 mils, for a combined thickness of 4 mils. This thickness for the valve strips was found to provide the valve strips with sufficient stiffness to avoid conforming entirely to the adjacent bag wall films, and yet allow the valve strips to conform to some extent to one another, such that the valve strips sealingly close in the absence of pressure on the walls of the bag.
Air being evacuated from the storage bag travels between the two valve strips, and not between either the front bag wall and confronting valve strip or the rear bag wall and confronting valve strip. Since the valve strips are smooth, regardless of any texture imparted to the bag walls, a more reliable seal of the valve is obtained. When no pressure is physically exerted on the walls of the compartments, ambient atmospheric pressure is sufficient to press valve strips together, thereby impeding unwanted air from entering the elongated channels and the compartments respectively associated therewith. Due to the length of each elongated channel and the somewhat tortuous path therethrough that air would need to take to re-enter the compartments, when no pressure is exerted on the bag walls, atmospheric pressure is sufficient to keep the bag walls pressed together on the outside of the elongated channels, which in turn presses the valve strips together, thereby sealing the valves, as shown in
In accordance with one method of manufacturing evacuable storage bags of the type shown in
The respective tacked constructions are then advanced intermittently toward a dual zipper application station. During this advancement, the webs of bag film are aligned and brought together in overlapping relationship with the valve strips facing and in contact with each other. At the same time, a pair of substantially identical zipper tapes each zipper tape comprising a respective pair of interlocked zipper strips are paid out from first and second zipper tape supply reels respectively and guided into respective positions sandwiched between the respective marginal portions of the overlapping bag webs. In accordance with one embodiment, the dual zipper application station comprises two pairs of mutually opposing, reciprocatable heated sealing bars that join the zipper tapes to the bag webs by conductive heat sealing. The amount of heat and pressure applied to the zipper tapes and marginal portions of the bag webs must be sufficient to cause the bag making film (or a sealant layer thereof in the case of a laminated film), to soften or melt and then fuse to the contacting zipper strip during cooling, but not so great as to cause the closure profiles of the zipper strips to fuse together. Alternative methods of zipper/web joinder can be utilized, such as adhesive application or ultrasonic welding.
The section of the work in process that exits the dual zipper application station consists of the first and second bag webs in overlapping relationship, the left marginal portions of the first and second bag webs being joined to a first zipper tape situated therebetween, the right marginal portions of the first and second bag webs being joined to a second zipper tape situated therebetween, the first valve strip being tacked to a central portion of the first web and carried thereby, and the second valve strip being tacked to a central portion of the second web and carried thereby. This section of the work in process is then advanced intermittently to a dual ultrasonic welding station, where the zipper tapes are ultrasonically welded together to form respective zipper joints during each dwell time. Zipper joints are made at regular spaced intervals along the length of the zipper tapes, one zipper joint per package-width section of zipper tape. In the discrete areas where ultrasonic welding occurs, the closure profiles of the zipper tape are flattened. The ultrasonic welding station may comprise an ultrasonic horn and an anvil, one or both of which is reciprocatable.
Preferably after zipper joinder, sliders can be inserted on the zippers in a manner well known in the art.
The particular section of the work in process under discussion is then advanced intermittently to a cross sealing station, where a respective cross seal (see, e.g., cross seals 26 in
At the next station, four sets of mutually confronting, reciprocatable heated sealing bars (all disposed parallel to the machine direction) are pressed against the central section of the work in process, i.e., where the valve strips are located. The two inner sets of sealing bars are aligned with each other, but staggered relative to the two outer sets of sealing bars, which are likewise aligned with each other. During each dwell time, these heated sealing bars are extended for a duration of time sufficient to form the zones of joinder 66, 68, 70 and 72 (seen in
Following the completion of all of the foregoing method steps, the work in process consists of a chain of storage bags, each storage bag comprising a respective double valve assembly of the type shown in
In order to make a succession of two-compartment bags, the cross sealing station operates during each dwell time, as does the cutting station. However, the automated production line can be altered to produce four-compartment, six-compartment, eight-compartment, etc. bags by controlling the cutting station to respectively operate only once every two work cycles, three work cycles, four work cycles and so forth.
While the invention has been described with reference to various embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements 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, welded, 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, co-extrusion (e.g., of zipper and bag), etc. As used in the claims, the prefix “multi” means two or more. 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.
