WO1993003933A1

WO1993003933A1 - Reinforced expandable folder

Info

Publication number: WO1993003933A1
Application number: PCT/US1992/006989
Authority: WO
Inventors: Theodore V. Kachel; Jonathan B. Rivlin; Robert E. Hawes, Jr.; Lee A. Boy; Setsuo Kanamoto; Eric R. Aaldenberg; John Heffernan; James J. Lynch; Cheryl Dellacroce-Steinberg
Original assignee: Esselte Pendaflex Corporation
Priority date: 1991-08-21
Filing date: 1992-08-20
Publication date: 1993-03-04
Also published as: CA2076359A1; CN1077682A; AU2484292A; MX9204873A

Abstract

An expandable folder (10) includes a front panel member (11), a rear panel member (12), and a gusset member (14) which connects peripheral portions of the front and rear panel members. The gusset member includes a sheet having accordion-like folds, with terminal folds of the sheet being wider than the other folds, and the terminal folds are connected to the front and rear panel members. The folder further comprises interior reinforcing strips (22, 26) positioned along at least part of the connection between the gusset member and panel members peripheral portion for preventing separation of the front and rear panel members from the gusset member. Reinforcing strips (24) may also be provided along the top or corners of the gusset member or on outer peripheral portions of the panel members. In addition, the outer surfaces of the panel members may be coated with a polymer (27) to water-proof the folder and to protect it from disfigurement.

Description

REINFORCED EXPANDABLE FOLDER

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to paper office supplies, and, in particular, to expandable folders having reinforced sides, corners, and edges for making the file stronger and more durable.

2. Description of the Prior Art

Expandable folders are a necessary tool in the modern office or business and are also commonly used in homes and schools. These folders are typically constructed of rectangular front and rear panel members having accordion-like folds along the bottom and sides, commonly called gussets, which allow the folder to expand from front to back. The folders are shipped and stored in their compact state. When put into use, the gussets allow the folder to expand gradually as the folder becomes filled with documents, papers or other items.

A typical five piece construction is used for many expandable folders. This construction includes first front and rear panel members and a combination side and bottom gusset attached thereto, with second front and rear panel members attached to the first front and rear panel members, respectively. Typically, the gusset ends are secured between the first and second panel members.

These expandable folders are often filled (or overfilled) with documents until the gussets are completely extended and no additional documents can be placed in the folder. However, filling an expandable folder in this manner often leads to premature failure of the folder due to tearing at certain critical or highly stressed locations. These critical locations are most commonly at the point of intersection of the gusset with the front and rear panel members, at the corners of the folder, along the top edge of the gusset, and in the gusset itself.

Fully expanded folders usually tear at the point of intersection of the gusset with the front and rear panel members because when these expanded folders are subsequently looked through to locate a particular document, the searcher often tries to expand the folder further in order to see and retrieve the documents stored therein. Also, when the retrieved document must be returned to the folder, the searcher will again stretch the folder to make room so that the document may be easily placed therein. However, because the gusset is already fully expanded, the only way for the folder to expand further is for the folder to tear at the point where the gussets are joined to the front and rear panel members of the folder.

A fully expanded folder is also relatively heavy, and this weight contributes to failure of the folder in variety of ways. For instance, the folders are often picked up by only the front or rear panel member, which causes the panel member to completely tear away from the gusset. Further, when a fully expanded folder is repeatedly placed on a desk or tabletop, the rubbing of the corners, sides and bottom of the folder on the tabletop surface causes these areas of the folder to fray or wear away. This fraying and wearing away detracts from the neat appearance the folders should have, further weakens the folder and can cause the loss of small items stored therein. Finally, when a full folder is dropped, the folder will burst or split along the seam between the gusset and front or rear panel members, scattering the folder or contents around the place of impact. Expandable folders are also normally stored on shelves with their front and rear faces perpendicular to the length of the shelf. When these folders are retrieved, fingers are usually placed over the top edge of the gusset so that the folder can be pulled off the shelf. However, because the fully expanded folder is relatively heavy, pulling the folder in this manner often leads to separation of the gusset from the front and rear panel members. Further, the fingers usually pull the folder from the same place on the gusset over and over again. Over time, dirt and sweat will accumulate on the gusset, thereby fraying and weakening the gusset and causing the gusset to unexpectedly tear when the folder is retrieved.

These folders often become wet during use, either by being exposed to rain or snow during transport from one location to another, or when water or beverages such as coffee, tea, or soda are accidentally spilled on them, or due to moisture in the air when the folder is stored. When these folders become moist or wet, they weaken considerably and are very susceptible to tearing. Further, the wet folders become deformed, weakened and deteriorate rapidly when they become dry, and are also very susceptible to tearing in this condition.

Finally, these folders are often identified by pressure-sensitive adhesive labels attached to the front or rear panel member. However, when it is desired to remove these labels, the folders often become disfigured due to the inability to separate the adhesive on the label from the fibers in the panel members. Thus, these folders are often discarded simply because they no longer have a neat appearance.

The applicants have identified the above problems and have established that a need exists for an expandable folder that solves such problems. In particular, there is a need for an expandable folder of superior strength that is durable, will not fail when it is filled to capacity, is resistant to liquids, and which will maintain a neat, sturdy appearance.

SUMMARY OF THE INVENTION

The present invention provides an expandable folder which includes reinforcing material to increase the strength and durability of the folder. This folder comprises a front panel member having first and second surfaces, opposed sides and a bottom, a rear panel member having first and second surfaces, opposed sides and a bottom, and an expandable gusset member having a top, bottom, opposed side gussets, and two corners. The bottom and opposed side gussets of the gusset member connect peripheral portions of the bottom of the front and rear panel members and at least a portion of the sides thereof so that the first surfaces of the panel members face each other to define the inner boundaries of the folder, which form a cavity for receiving file materials.

The gusset member comprises a sheet having a plurality of accordion-like folds, preferably, with the terminal folds of the sheet being wider than the other folds. These terminal folds are connected to the front and rear panel members to enhance the connection therebetween.

Interior reinforcing means may be applied to the first surfaces of the front and rear panel members in order to prevent separation of the front and rear panel members from the gusset members when the folder is used. Preferably, the interior reinforcing means is positioned adjacent to at least part of the connection between the sides of the gusset member and panel member peripheral portions. Reinforcing means may also be applied to the corners of the gusset member. This reinforcing means extends along the corner and a portion of the side and bottom of the gusset member to enhance the wear resistance of the folder.

In one embodiment, reinforcing material is applied across a portion of each side gusset of the folder and onto a portion of the front and rear panels to strengthen and increase the connection of each side gusset to the panel members and the durability of the folder.

In another embodiment, the side gusset members include a top edge, and the reinforcing material is applied in the form of a band to the side gusset members at the top edge thereof.

The reinforcing material may be affixed to the outer surface of the side gussets and onto the outer surfaces of the panel members of the folder, preferably in the form of a band which extends across the side gusset members and the outer surfaces of the panel members to completely engage the outside perimeter of the entire folder. If desired, the reinforcing material can completely cover the gusset member and portions of the panel members.

Alternatively, the reinforcing material may be affixed to the inner surface of the side gusset member and onto at least a portion of the inner surfaces of the panel members. Again, the reinforcing material may be applied in the form of a band which extends across the side gusset members and the inner surfaces of the panel members to completely engage the inside perimeter of the entire folder, or to completely cover the gusset member and portions of the panel members.

The reinforcing material may also be used in the form of reinforcing strips which are placed adjacent the top edge of the side gusset member at each connection of the side gusset member to the front and rear panel members. Preferably, a first reinforcing strip is affixed to each outer layer of the front panel member, extending at an angle over the top edge of the adjacent side gusset member and onto the inner layer of the front panel member; and a second reinforcing strip is affixed to each outer layer of the rear panel member, extending at an angle over the top edge of the adjacent side gusset member and onto the inner layer of the rear panel member. These reinforcing strips should extend onto the panel members beyond the width of the terminal ends of the gusset connected thereto. Also, these strips may extend over the side gusset members at any angle between 30 and 60 degrees.

Another aspect of the present invention relates to an expandable folder that has reinforcing means applied to the top edge of the side gusset members, which may also be applied to the front and rear panel members, for providing resistance against tearing of the top edge of the side gusset members, as well as resistance to separation of the side gusset members from the front and rear panel members when the folder is used.

One type of such reinforcing means may be prepared by folding the top edge of each side gusset member onto itself to form a double layer of material. If desired, each folded top edge may be secured to the side gusset member with an adhesive. Alternatively, the reinforcing means may be a strip of reinforcing material which extends over the top edge of each side gusset member and onto a portion of each side thereof.

In yet another embodiment, each side gusset member comprises a multiple layer composite structure and the reinforcing means is prepared by folding the top edge of each side gusset member onto itself and, if desired, secured with an adhesive to form a double multiple layer construction.

Alternatively, the terminal end portions of each side gusset member and the applied reinforcing means described above do not have to be secured or attached to each other. In this arrangement, multiple end portions are provided at each end of the side gusset member and each may be attached to a different panel member surface. Also, more than one terminal end portion may be applied to one panel member surface.

Another embodiment of the present invention relates to reinforcing means which is applied upon the peripheral portions of the front and rear panel members, wherein the gusset member is attached to the reinforcing means to enhance the tear resistance between the connection of the gusset member an the panel members.

This reinforcing means preferably comprises a band of reinforcing material which is applied to a portion of the sides of the outer surfaces of the front and rear panel members and is at least as wide as the terminal end portions of the gusset member. Advantageously, the reinforcing means may also be a strip of reinforcing material on each panel member which extends from the bottom to a location above the point of attachment of the gusset member, and, if desired, to substantially cover the entire outer surface of each panel member.

For the preceding embodiments, the reinforcing material preferably comprises a thermoplastic film, a thermoplastic fabric or a thermoplastic film/paper composite.

Another expandable folder has an integral front panel member, bottom gusset and rear panel member and is formed from a single blank of material. Thus, separate side gussets are provided for attachment to the front and rear panel members to form the folder. The single blank of material and the side gussets may each be formed of paper, a thermoplastic film, a thermoplastic fabric or a thermoplastic film or fabric/paper composite. If desired, the side gussets may include bottom tab members and a bottom portion for attachment to the bottom gusset, and the reinforcing means may extend from the front panel member across the bottom gusset to the rear panel member.

Yet another expandable folder in accordance with the invention is formed from components which have terminal end portions for attachment to one of the panel members or the side gusset members to strengthen and increase the connection of each side gusset to the panel members as well as the durability of the folder. Again, the front panel member, gusset, rear panel member and terminal portions may be integral and formed from a single blank of material. These terminal portions can extend from side gussets and be connected to the panel members, or can extend from a panel member and across an adjacent side gusset for attachment to the other panel member. Advantageously, four terminal portions are present, two of which extend from the side gussets and are connected to the panel members, and two of which extend from a panel member and across an adjacent side gusset for attachment to the other panel member.

A preferred expandable folder includes reinforcing means in the form of a sheet of reinforcing material which substantially covers the entire outer surface of each panel member to enhance the tear resistance of the connection of the gusset member to the panel members. Additional panel members are secured to each reinforcing means on the outer surfaces of the panel members to retain the gusset attachment therebetween. Advantageously, the front panel member and additional panel members are made of red wallet material, the rear panel member is made of manilla paper, the gusset is made of plastic film reinforced paper, the reinforcing means comprises a thermoplastic film or a thermoplastic film/paper composite, and the rear panel member has a height which is greater than the front panel member for viewing the top portion thereof for purposes of viewing filing indicia which may be placed thereupon.

Finally, a coating may also be applied on to the second surfaces of the front and rear panel members to improve the resistance of the folder to penetration by liquids and to prevent disfigurement of the folder due to repeated labeling and relabeling.

The coating and reinforcing means may be applied alone or in combination to impart the desired improvements to the folder. The optimum design includes the combination of all the reinforcing means and the coating.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will be more readily apparent from the following detailed description and drawings of an illustrative embodiment of the invention in which:

Fig. 1 is a perspective view of the expandable folder of the present invention.

Fig. 2 is a perspective detail view of a bottom corner of the expandable folder of the present invention.

Fig. 3 is a longitudinal section of the gusset of the expandable folder taken along line III- III of Fig. 1.

Fig. 4 is a transverse cross section of the gusset taken along line IV-IV of Fig. 1.

Fig. 5 is a plan view of an unfolded gusset. Fig. 6 is a longitudinal section of the gusset taken along line VI-VI of Fig. 5.

Fig. 7 is a schematic drawing of the flexographic printing process.

Fig. 8 is an enlarged detail view of the anilox metering roll used in the flexographic printing distribution system.

Fig. 9 is an additional schematic drawing of the flexographic printing process.

FIG. 10 is a perspective view of an expandable folder having a band of reinforcing material which extends completely around the folder;

FIG. 11 is a perspective view of an expandable folder having reinforcing strips which are positioned across the gusset at each side of the folder;

FIG. 12 is a perspective view of an expandable folder having reinforcing strips positioned diagonally over the top edge of the gusset where attached to the front and rear panel members; FIG. 13 is a perspective view of an expandable folder having a cover and reinforcing strips which are positioned at the top of the gusset and the corners of the folder;

FIGS. 14-19 illustrate various gusset top reinforcements for use in the expandable folders of the invention, with FIG. 14 providing a perspective view of the top portion of a gusset and FIGS. 15-19 representing cross-sectional views of various reinforcement arrangements taken along line A—A of FIG. 14;

FIG. 20 is a front view of an integral front panel, bottom gusset and rear panel blank in a flat position prior to creasing the gusset folds and panel member-gusset fold lines; FIG. 21 illustrates a side gusset for joining the front and rear panels of the blank of FIG. 20;

FIG. 22 is a perspective view of the integral blank of FIG. 20 which is provided with two side gussets of FIG. 21;

FIG. 23 illustrates the use of front and rear panel reinforcement in a five-piece expandable folder which optionally includes gusset top and gusset corner reinforcement;

FIG. 24 is a front view of a three piece expandable folder which is made from a blank having less than full outer reinforcement;

FIG. 25 is a cross-sectional view of the front panel member of the folder of FIG. 24 taken along line 25—25 thereof;

FIG. 26 is a front view of an integral front panel, bottom gusset, side gussets and rear panel blank in a flat position prior to creasing the gusset folds and panel member-gusset fold lines;

FIG. 27 is a perspective view of a folder assembled from the blank of FIG 26;

FIG. 28 is a front view of a portion of a blank which is similar to that of FIG. 26, except that the four corners of the blank are cut away; and

FIG. 29 is a perspective view of a folder assembled from the blank of FIG 28.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A more complete understanding of certain features of the present invention can be found in U.S. Patent 5,066,045, the disclosure of which is expressly incorporated herein by reference thereto for the purpose of further describing and defining such features.

The term "expandable folder" is used herein to mean and include expandable pockets, wallets, files and jackets, with or without covers or partitions which are separate or attached to one of the panel members.

Referring to the drawings and particularly to Figs. 1 and 2, there is illustrated a first embodiment of an expandable folder 10 in accordance with the present invention. Folder 10 comprises a front panel member 11, a rear panel member 12, an open top 13 and connection means between front panel member 11 and rear panel member 12 in the form of a z- folded expandable gusset 14. Gusset 14 forms a portion of the sides 15 and the entire bottom 16 of folder 10.

Front panel member 11 comprises an inner layer 11a and an outer layer lib which are cut or stamped from a web 35 of heavy paper or cardboard such as red wallet, red rope, or manila. Inner layer 11a and outer layer lib are glued, stamped or otherwise attached to each other to form front panel member 11. Likewise, rear panel member 12 comprises an inner layer 12a and an outer layer 12b which are cut or stamped from a web 35 of heavy paper or cardboard such as red wallet, red rope or manila. Inner layer 12a and outer layer 12b are also attached to each other by gluing, stamping, or the like to form rear panel member 12. In addition, the material of the panels can be folded upon itself and adhered together to form both the outer and inner panel members. A typical arrangement combines anilla paper for the inner layer 12a of the rear panel member 12 and red wallet for the other three members, but any combination can be made depending upon the anticipated usage of the folder 10.

However, before outer layers lib, 12b are stamped from web 35, web 35 is preferably treated on one side with a liquid resistant acrylic coating 27. The treated side of web 35 will form the outer surface of outer layers lib, 12b, and coating 27 will act to prevent moisture permeation into folder 10. Further, coating 27 will allow for easy labeling and relabeling of folder 10 by preventing the adhesive on the labels from actually contacting the surface of folder 10, thereby preventing disfigurement of folder 10 due to repeated labeling and relabeling. Preferably, coating 27 will be a styrenated acrylic water based emulsion 36, purchased from Roy al, Inc. of Newport, New Hampshire, which is applied by a flexographic press procedure, as discussed herein.

As shown in Figs. 3, 4, 5 and 6, gusset 14 comprises a sheet of laminated, flat paper 19 that is repeatedly folded on top of itself in a well known manner to give it an accordion-like expanding capability that permits the folder 10 to gradually expand as it is filled with items to be stored. The paper forming gusset 14 is of sufficient length to extend around the sides 15 and bottom 16 of the folder 10, and the width of the paper is selected in accordance with the desired expanded thickness of the folder. Gusset 14 ends in terminal folds 17, 18 which are approximately the same size as the gusset folds. Alternatively, these terminal folds 17, 18 may be at least twice as wide as inner folds 28 of gusset 14, or at least 7/8 of an inch wide, whichever is greater. It is preferred to use the extended width terminal folds 17, 18 to increase the surface area over which the gusset 14 contacts the panel members 11, 12, thus strengthening the bond therebetween. However, gussets having side portions 15 with terminal folds of double width in combination with bottom portions 16 with terminal folds of standard width, i.e., as wide as the inner folds, could also be used for certain folders, since the stress on the terminal folds of the bottom portion 16 of the gusset 14 is not as great as the stress on the terminal folds of the side portions 15. Of course, the greatest strength joint of the gusset to the panels is when all of the terminal folds are of double width.

The extended or double width gusset terminal folds 17, 18 can be achieved by unfolding the last gusset fold on each end of the gusset so as to provide the required width prior to attachment to the front and rear panels 11, 12. Alternatively, the extended width can be provided by allowing the unfolded end portions to be of the appropriate dimensions. The latter arrangement is preferred when plastic or polymer reinforcement is provided on the gusset, because folded plastic material has a memory which encourages the material to retain its folded shape, thus causing difficulty during the subsequent assembly and manufacture of the gusset onto the panels.

These terminal folds 17, 18 of the gusset 14 may be attached to the front and rear panels 11, 12 in a number of configurations. If desired, the end portions may be attached to the outer or inner surfaces of the panels, provided that the entire surface area of the end portion is attached to the panel. Since a typical panel includes inner and outer members, it is preferred from an aesthetic viewpoint to attach the end portions between the panel members. To do this, the end portions are positioned between the inner and outer layers of the front and rear panels 11, 12 prior to attachment of the members, such that when the members are attached in the manner described above, the terminal folds 17, 18 of the gusset 14 are joined to the front and rear panels 11, 12. In addition, the end portions of the gusset 14 may be provided with a suitable adhesive to increase the strength of their connection to the panels.

Before flat paper 19 is folded into gusset 14, a reinforcing material, preferably Tyvek® (DuPont registered trademark for spun bonded olefin) or some other water resistant and durable material, may be affixed to flat paper 19. This reinforcing material will provide enhanced strength and resistance to tearing to folder 10, as compared to expandable folders available in the prior art.

A first location for gusset reinforcing material is along the entire length and width on one side of the flat paper 19. This reinforcement will be identified as a reinforcement layer 20. Although reinforcement layer 20 is preferably attached to only the side of flat paper 19 that will become the outer surface of gusset 14, a similar reinforcement layer 20 may also be attached to the other side of the flat paper 19 so that both sides are reinforced. Reinforcement layer 20 will prevent the re-shaping of folds 28 through repeated expansions and contractions of folder 10 and will protect gusset 14 from liquids.

A second location for reinforcing material is upon a portion of the reinforcement layer 20 at the locations where corners 23 will subsequently be formed in folder 10. Corners 23 are formed when flat paper 19 is folded to form gusset 14 and gusset 14, in turn, is attached to the periphery of both the front panel member 11 and rear panel member 12. This reinforcement will be referred to as corner strips 21. Preferably, these corner strips 21 extend along the entire width of reinforcement layer 20, as shown in Figure 4. Corner strips 21, in conjunction with reinforcement layer 20, reinforce and provide exceptional wear resistance to corners 23, as discussed hereinbelow.

A third location for reinforcing material is over the common edge 25 of flat paper 19 and reinforcement layer 20. This reinforcement will be referred to and as edge strip 24. Edge strip 24 is affixed along the entire width of the upper portion of flat paper 19, over common edge 25, and along the entire width of the upper portion of reinforcement layer 20 (see Figs. 3, 4 and 6). Edge strip 24, in conjunction with coating layer 20, will protect the upper portion of gusset 14 from dirt and moisture and will provide additional resistance tear to gusset 14.

As noted above, the most preferred reinforcement material is a Tyvek® thermoplastic film which includes an adhesive to attach it to panel members 11, 12 or gusset 14. It is possible, however, to use other thermoplastic films or tape to achieve similar results. Also, paper strips, which are glued or otherwise attached to the area to be reinforced, may be used. If so, it is preferred to use a paper material which is treated by a polymer coating or is laminated to a plastic material in order to be resistant to moisture penetration.

Gusset 14 is preferably attached to front panel member 11 and rear panel member 12 by gluing, stamping, or otherwise attaching terminal fold 17 in between inner layer 11a and outer layer lib while layers 11a, lib are attached to each other, and by gluing, stamping, or otherwise attaching terminal fold 18 in between inner layer 12a and outer layer 12b while layers 12a, 12b are attached to each other. Thus, inner layers 11a, 12a extend to substantially the outermost ends 17a, 18a of the first and last gusset folds, respectively. It is also contemplated that terminal folds 17, 18 may be attached solely to the interior surfaces of inner layers 11a, 12a, respectively, or to the exterior surfaces of outer layers lib, 12b, respectively. With either method of attachment, terminal fold 17 will be positioned along vertical edges lie and bottom edge lid of front panel member 11, and terminal fold 18 will be position along vertical edges 12c and bottom edge 12d of rear panel member 12.

As discussed above, terminal folds 17, 18 preferably have an extended width which is at least twice the width of interior folds 28 or at least about 7/8 of an inch, whichever is greater. Thus, the surface area over which gusset 14 is attached to front panel member 11 and rear panel member 12 is very large, as compared with attachment surface areas of prior art folders, and the bond between terminal folds 17, 18 and front panel member 11 and rear panel member 12, respectively, is exceptionally strong. Accordingly, if folder 10 were pulled by gusset 14 in a direction parallel to front panel member 11 or rear panel member 12, gusset 14 would not separate or tear away from front panel member 11 or rear panel member 12 as would the gussets of prior art folders.

After folder 10 has been assembled, additional reinforcement is applied to provide even greater strength and tear resistance to folder 10, as compared to prior art expandable folders. This reinforcement is in the form of interior reinforcing strips 26 which are affixed to the exposed surface of inner layer 11a from bottom edge lid to top edge lie along vertical edges lie. Likewise, interior reinforcing strips 22 are added to the exposed surface of inner layer 12a from bottom edge 12d to top edge 12e along vertical edges 12c. Interior reinforcing strips 26, 22 insure that when folder 10 is stretched after gussets 14 are already fully expanded, i.e. when folder 10 is hyper-expanded, inner layers lla, 12a have greater resistance to separation from gusset 14.

Additionally, exterior reinforcing strips 29 are added to the exposed surface of outer layer lib from bottom edge lid to top edge lie along vertical edges lie. Likewise, exterior reinforcing strips 30 are added to the exposed surface of outer layer 12b from bottom edge 12d. to top edge 12e along vertical edge 12c. Exterior reinforcing strips 29, 30, may provide even greater structural stability and durability to folder 10. As discussed above, coating 27 is applied to web 35 before outer layers lib, 12b of panel members 11, 12, respectively, are formed therefrom by a flexographic printing procedure. Flexographic printing is a well-known form of rotary printing in which aniline inks or layers of other chemicals are applied to various surfaces by means of rubber or other elastomeric plates. Flexographic printing is particularly well suited for applying coating layers 27 on relatively coarse surfaces.

The flexographic printing process used in the present invention is preferably repeated twice to form coating 27. Thus, layer 27 will preferably comprise an inner layer 27a and an outer layer 27b. As shown in Fig. 7, the flexographic printing process typically employs a fountain 40; a reverse-angle doctor blade assembly 31 attached to fountain 40; an anilox metering roll 32 in operative relation with fountain 40 and doctor blade 31; a plate cylinder 33 in operative relation with anilox metering roll 32; and an impression cylinder 34 which presses web 35 between impression cylinder 34 and plate cylinder 33.

As discussed above, coating 27 will be a styrenated acrylic water based emulsion 36. However, because emulsion 36 typically has a viscosity greater than 3 minutes through a No. 2 Zahn cup, it is desirable to reduce this viscosity before forming inner layer 27a and outer layer 27b. Thus, on the first pass of web 35 through the flexographic printing process to form inner layer 27a, fountain 40 will be filled with a fluid 36a which comprises water and emulsion 36. Fluid 36a has a viscosity between 55 to 60 seconds through the same No. 2 Zahn cup. Similarly, on the second pass of web 35 to form outer layer 27b, fountain 40 will be filled with a fluid 36b which comprises water and emulsion 36. Fluid 36b has a viscosity of 25 seconds through the same Zahn cup. As shown in Fig. 8, small indentations or cells 38 are engraved into the entire surface of a flexible rubber plate 39 by means of well-known plastic molding techniques. The average number of cells 38 per square inch of surface area is typically about 100,000, but, depending on the application intended, the number of cells 38 may vary from 30,000 to 300,000. Rubber plate 39 is then affixed to the circumference of anilox metering roll 32 with the opening of cells 38 extending radially outward.

The flexographic system operates by rotating anilox metering roll 32 against fluid 36a in fountain 40, thereby filling cells 38 on the surface of anilox roll 32 with fluid 36a. As anilox roll 32 rotates, doctor blade 31 shaves excess fluid 36a off the surface of anilox roll 32. Anilox roll 32, which rotates in contact with plate cylinder 33, then transfers the contents of cells 38 to the surface of plate cylinder 33 to form a layer of fluid 37a thereon. Since the size of cells 38 are accurately controlled, the density of fluid 37a on plate cylinder 33 is relatively uniform to within a variation of about 2% or less.

Plate cylinder 33 continues to rotate, thereby transferring the uniform layer of fluid 37a to web 35. The complementary rotation of impression cylinder 34, which squeezes web 35 between plate cylinder 33 and impression cylinder 34, secures the layer of fluid 37a to web 35 to form inner layer 27a on web 35.

As shown in Fig. 9, the flexographic printing process described above is then repeated with fluid 36b in fountain 40 to form layer 27b on top of inner layer 27a, thereby forming coating 27 on web 35. Web 35 will then pass to a cutting or stamping station where web 35 will be formed into outer layers lib, 12b. Thus, coating layer 27, which will be on the outer surfaces of folder 10, will prevent liquids from penetrating into folder 10 and will prevent disfigurement of folder 10 due to repeated labeling and relabeling.

Fig. 10 illustrates an expandable folder 110 of the same basic construction and materials as folder 10 in Fig. 1. Folder 110 comprises a front panel 112 and a rear panel 114 connected by an expandable gusset 116 which forms the bottom and the sides 118 of the folder 110. The front panel 112 comprises an inner member 120 and an outer member 112. Similarly, the rear panel 114 comprises an inner membrane 124 and an outer member 126. The folder is open along the top to facilitate insertion of papers, documents, and other items which are to be stored in the folder.

To reinforce the joint between the top of the gusset and the panels, a band of reinforcing material 134 is applied to the outer surfaces of the front panel 112, the side portions 118 of the gusset 116, and the rear panel 114, thus surrounding the entire folder 110. The reinforcing band 134 is positioned adjacent the top edges of the sides of the folder 110 and over the end portions 130 of the gussets attached thereto. The band 134 preferably has a width of about one inch, although other dimensions can be utilized.

The band 134 is preferably formed of a plastic material, such as TYVEK® thermoplastic material which includes an adhesive thereon for attachment of the band to the panel members 112, 114 and side portions 118 of the gusset 116. Alternatively, if the TYVEK® material is not adhesive- backed, the reinforcing band could be affixed to the folder 110 using a suitable glue or other adhesive. This TYVEK® material is generally formed as a tape or fabric which is commonly laminated onto a substrate such as paper. In addition, other thermoplastic films or tapes could also be used to form the band 134. These films or tapes could also be adhesive-backed or affixed to the folder 110 with a suitable adhesive or glue that is applied either to the band 134 or to the folder 110. Fiberglass or other filament containing tape could also be used as the reinforcing material. Furthermore, a plastic film/paper laminate of composite, with or without an adhesive backing, can be used to form a band having even further increased strength.

As discussed above, the expandable folder 110 is typically filled to capacity or over-filled with documents and items to be stored. Often, the filled folders are stretched or expanded beyond their limits as documents are retrieved and then returned to the folder, putting stress on certain locations of the folder 110, such as where the gusset 116 is attached to the panels 112, 114, and often causing tearing at this connection. Further, when the folders are retrieved from filing drawers or shelving units, the folder 110 is often pulled by one of the panels, frequently resulting in separation of the gusset 116 from the panels 112, 114. Tearing can also result when a full folder is dropped. The presence of the reinforcing band 134 at the intersections between the gusset 116 and panel members 112, 114 strengthens the folder 110 and prevents separation of the gusset from the panel members when these types of pulling or expansion forces are applied to the folder. Thus, the present invention provides an expandable folder having increased strength and durability which will increase the life of the folder.

In another embodiment of the invention, the band of reinforcing material may be applied to the inner surfaces of the folder 110 either alone or in combination with the outer reinforcing band 134. The inner band is preferably the same width as the outer band described above and is preferably positioned adjacent the top edges of the side portions 118 of the gusset 116, across the inner layers 120, 124 of the panels 112, 114, respectively, and over the end portions 130 of the gusset 116 attached thereto. In this manner, the inner band reinforces the intersections of the side portions of the gusset 116 and panels 112, 114 at locations where pulling and expansion forces are most often applied to the folder, thus providing additional strength and durability at these locations.

The inner reinforcing band is also preferably formed of a strip of TYVEK® material which has an adhesive backing and is applied to the front panel 112, rear panel 114, and side portions of the gusset 116. As discussed above, other suitable reinforcing materials with or without adhesive backing may also be used as this band.

FIG. 11 illustrates another embodiment of a reinforced expandable folder 140 wherein like parts have been numbered correspondingly. In this folder 140, two separate reinforcing bands 142 are provided to strengthen the locations where the gusset 116 is attached to the front and rear panels 112, 114 of the folder. Each band 142 is made of the same material and has the same width as the other bands discussed above, but these bands 142 are applied only across a portion of the outer layer 126 of the rear panel 114, the side portion 118 of the gusset 116, and a portion of the outer layer 122 of the front panel 112. The reinforcing strips 142 are positioned on the outer surfaces 122, 126 of the front and rear panel 112, 114, respectively, to extend beyond the width of the terminal ends 130 of the gussets 116 which are attached thereto. In this manner, the reinforcing bands 142 provide additional strength and support when pulling and expanding forces are applied to the gussets 116 at its intersection with the panel members 112, 114. Thus, the bands 142 prevent tearing and separation of the gusset 116 from the panel members 112, 114 and increase the durability and longevity of the folder.

If desired, the ends of these bands 142 can be placed between the panel members for aesthetic purposes. In this embodiment, the gusset would be attached only to the inner panel members prior to attachment of the bands 142 and the outer panel members. Alternatively, these bands 142 can be attached to the outer panel members prior to the attachment of the gusset thereto, followed by the attachment of the inner panels to the outer panels. A third aspect contemplates the attachment of the bands 142 to the inner panel members after the gusset and panels are attached together. In this arrangement, the bands 142 would extend to the top of the gusset to provide resistance against tearing at that location.

Yet another embodiment of an expandable folder 150 is illustrated in FIG. 12 where again like parts have been numbered correspondingly. The top corners 152 of expandable folder 150 where the top edge of the gusset 116 is connected to the panel members 112, 114 has been found to be a highly stressed location which is prone to failure by tearing. Thus, folder 150 includes reinforcing material applied to these top corners 152 to increase the tearing resistance at these locations. The reinforcing material is applied in four bands or strips preferably about one to two inches in width which are placed over the corner junctions 152 at an angle of about 45 degrees. Placing these bands at an angle provides additional resistance against vertical separation forces, as well as similar resistance to horizontal forces, compared to the horizontally applied bands of FIGS. 10-11. Preferably, a first pair of bands 154 extends over the top corners of the side portions 118 of the gusset 116 adjacent the front panel 112. Each band 154 is applied to the outer surface 122 of the front panel 112 and extends diagonally over the corner intersection 152 of the gusset 116 for attachment to the inner surface 120 of the panel. Similarly, a second pair of bands 156 extends over the top corners 152 adjacent the rear panel 114, wherein each band is applied to the outer surface 126 of the rear panel 114 and extends diagonally over the top corners 152 for attachment to the inner surface 124 of the rear panel. These bands can be placed at any desired angle between 30 and 60 degrees.

The bands 154, 156 are applied to both the inner and outer surfaces of the panels 112, 114 such that the reinforcing material extends beyond the width of the terminal ends 130 of the gusset 116 connected thereto. The extension of the reinforcing material past this location provides additional reinforcement and strength when pulling and expansion forces are applied to the gusset 116, advantageously increasing the durability and longevity of the expandable folder 150.

When inner and outer panel members are utilized, bands 154, 156 can be applied after the gusset is attached to the outer surface of the inner panel members and prior to attachment of the outer panel members thereto. Thus, after connection of the outer panel members, bands 154, 156 would be visible only on the inside of the folder. If desired, these visible portions of bands 154, 156 can be covered with inner strips.

Alternatively, these bands 154, 156 can be attached to the outer panel members after the gusset is attached to the inside surfaces of the outer panel members. Next, the inner panel members are attached to the outer panel members to cover the gusset and bands. In this arrangement, the bands 154, 156 would be visible only on the outside of the folder. If desired, these visible portions of bands 154, 156 can be covered by the cover strips described above or by additional panel members which are secured to the outer panel members.

As in previous embodiments described herein, the reinforcing material preferably comprises TYVEK® material, although other suitable reinforcing materials may be used. Again, the reinforcing material may be adhesive-backed or may be attached to the folder with a glue or adhesive which is applied to the bands or the folder. The most preferred material for this band is a TYVEK® material reinforced paper that includes an adhesive backing.

All embodiments of the invention of FIGS. 10-12 may further include additional reinforcement at the bottom corners and on the panels at the outer and inner sides thereof.

FIG. 13 illustrates another folder 160 where again like parts have been numbered correspondingly. This folder includes such corner reinforcement 162 for providing additional wear and abrasion resistance to those areas of the folder. Also, the top portion of the rear panel 114 is configured to be a cover which can be used to protect the paper receiving cavity of the folder. This cover preferably has a plurality of score lines therein to conform to various expanded sizes of the folder. Also, the cover may include tie members, elastic bands or other means for securing it in a closed position on the file. If desired, this or other folders according to the present invention can also be designed to include or accommodate internal partitions or separators.

To prevent tearing of the top of the gusset and to reinforce the joint made between the sides of the gusset to the panels near the top of the gusset, various types of reinforcement can be applied to the top of the gusset, as shown in FIGS. 14-19.

FIG. 14 shows gusset 116 before end portions 130 are attached to the panels. Reinforcement 170 is provided at the top of the gusset 116 to provide resistance to tearing or detachment from the panels. In one embodiment, the top portion of the gusset is folded over itself and secured with glue or an adhesive to provide the reinforcement 170. It is immaterial as to which direction the top portion is folded, i.e., inside or outside as shown. When the gusset is made of a single sheet of material, such as paper, the top of the gusset will then have a double layer of material which is held together by the glue and which provides increased resistance to tearing. The inner surfaces of the end portions 130 are also provided with glue or an adhesive backing on one or both sides for attachment to the panels. The reinforced gusset can be attached to the inside or outside of the panels. When inner and outer panels are used, the reinforced gusset can be attached to any surface of either panel member, although, as noted above, attachment of the gusset between the panels is commonly used.

Instead of folding the top of gusset 116 upon itself, a strip of reinforcement can be applied to one side of the gusset 116 at the top thereof. Such reinforcement may be made of a wide variety of materials, including paper, cardboard, a plastic film of polyethylene, polypropylene, TYVEK® material, or the like. The plastic film may contain natural, synthetic of glass fibers or strands therein to provide further resistance to tearing or wear. The desired reinforcing material can be applied to the gusset using a suitable adhesive, which may be placed either on the reinforcement or on the gusset. Also, the reinforcing material can include an adhesive backing to facilitate attachment to the gusset. Again, a double layer is provided at the top of the gusset.

For a greater degree of tear resistance, the reinforcement material can be applied over the top of the gusset and onto both the inside and outside top portions thereof. A cross section of one side of the gusset of this embodiment is shown in FIG. 15, with the use of a paper gusset 172 and TYVEK® film reinforcing layer 174 being illustrated. The paper gusset 172 is provided with two layers of reinforcement 174. Again, end portion 130 has a double width compared to the width of the gusset folds for a more secure attachment to the panel members. When one panel member 178 is used, end portion 130 is provided with a glue or suitable adhesive for attachment thereto. When two panel members 178, 178A are used, glue 176, 176A is provided on each side of the gusset end portion 130 for secure attachment to the panel members 178, 178A.

An alternative attachment arrangement for the reinforcement 170 to two panel members 178, 178A is shown in FIG. 16. In this arrangement, reinforcement 170 is not attached to end portion 130. Instead, the end portion of reinforcement 170 is attached to panel member 178A, while end portion 130 of gusset 116 is attached to panel member 178. As described above with regard to FIG. 15, glue 176, 176A or other suitable adhesive is placed upon the end portions to assist in obtaining a secure bond to the panel members 178, 178A.

FIGS. 17-19 show another way that the top of the gusset can be reinforced. In this embodiment, the gusset is made of a plastic film reinforced paper construction, and the top of the gusset is folded upon itself and secured together. This arrangement provides for a laminate 180 having four layers at the top of the gusset, namely, paper layers 182, 182A and TYVEK® material layers 184, 184A. FIG. 17 shows the end portion 130 of the laminate attached to panel member 186 by the use of adhesive 188.

An alternative attachment arrangement for this laminate 180 to two panel members 186, 186A is shown in FIG. 18. In this arrangement, the end portion 130 of the gusset member is cut to provide dual end portions, each having a TYVEK® material reinforcement upon paper. This arrangement can also be achieved by not adhering the folded over portion to the other portion of the gusset. Thereafter, one end portion, made of paper 182 and film 184, is attached to panel member 186, while the other, which is made of paper 182A and film 184A, is attached to panel member 186A. As described above, glue 188, 188A or other suitable adhesive is placed upon these end portions to assist in obtaining a secure bond to the panel members 186, 186A.

FIG. 19 shows another attachment arrangement, where none of the layers 182, 182A, 184, 184A of the laminate 180 are secured to each other. This provides a great degree of versatility in connecting these layers to the panel members. For example, one preferred arrangement adheres the TYVEK® materials 184, 184A to the panel members 186, 186A, respectively. Since the TYVEK® material has greater strength than the paper layers, a stronger joint would be made. Depending upon the design of the folder, the TYVEK® material could be applied to either side of the respective panel members. In addition, the panel members could also be sandwiched between the TYVEK® materials and paper layers. Other arrangements can be devised depending on the desired configuration of the folder, and all possibilities are contemplated by this invention. If even further attachment strength is desired for the gusset to panel member connections, additional layers of plastic material can be added to these gusset top portions. The designer can best select the appropriate layers of reinforcement for the folder depending upon the specific end uses contemplated.

It should be noted that for each of the attachment arrangements of FIGS. 14-19, the sides of the panel members extend to the first fold line of the gusset so that the entire surface area of the appropriate side of the end portion of the gusset is adhered to the panel member. As noted above, the most secure attachments, i.e., those connections having the greatest strength, are achieved when the areas of the end portions which are adhered or attached to the panel members are maximized.

Referring now to FIG. 20, there is illustrated an integral blank 200 which includes a front panel member 202, bottom gusset 204 and rear panel member 206 for forming the folder. The back side of the blank, i.e., the side which forms the outer surfaces of the folder, is shown in a flat position prior to creasing the gusset folds 208 and panel member-gusset fold lines 210. This blank 200 can be made of a single sheet of any flat, flexible material, of which paper stock of the desired weight is typical. For expandable folders requiring greater strength, the blank 200 can be made of a plastic film of polyethylene, polypropylene, TYVEK®, or the like, or a plastic coated paper composite or laminate.

A reinforcing layer is provided at least on the outer surface of the gusset and onto the front and side panels to protect against frequent handling of the folder. The minimum amount of reinforcement to be applied would be a band or strip which covers the bottom gusset of the folder and the gusset-panel fold lines. This reinforcement, which is shown in FIG. 20 as the area between dotted lines A and B and the sides 212, 214 of the blank 200, strengthens and protects the folder from abrasion, such as when it is dragged along a file drawer bottom or a work station surface while carrying the weight of heavy stored papers or other file items. This strip can be easily applied by lamination onto the blank as the paper passes through the cutting machine. Alternatively, the strip can be glued to the paper, or can be applied as a liquid coating, as described herein.

The integral blank 200 of FIG. 20 has a multiplicity of horizontal depressions 208 which are folded or creased to form the bottom gusset. These gusset folds 208 are used to expand the folder to receive larger amounts or quantities of paper. Previous non-reinforced gussets were known to fail at these fold lines, with the paper tearing along the fold line during extended folding and unfolding. It was believed that the reinforcement would be advantageous in holding together the torn sections of paper as the folder deteriorates when used. However, it has been unexpectedly found that the application of reinforcement along the gusset fold lines substantially increases the useful life of the folder, because the paper does not break or tear at the fold line as it can when it is not reinforced as described herein.

It is advantageous to extend the reinforcement to the sides of the front and rear panel members in the areas where the side gussets are to be attached. These areas, shown in FIG. 20 as the area between dotted lines C and D and the sides 212, 214 of the blank 200, can be reinforced by application of strips of reinforcing material. These strips should be wider than the gusset ends which are to be attached to the panel sides. A plurality of these strips can be applied along portions of the sides of the panels as shown, or a single strip can be applied along each side of the blank in a direction perpendicular to the bottom strip. The side strips can be placed adjacent to the bottom strip, or they can overlap. The order or placement of the strips is not critical to the invention. For hand assembly of the folder, the reinforcing material along the sides and bottom can be prepared as an integral piece in the shape of an H and then applied to the blank.

Preferably, this reinforcing layer is applied as a single sheet or piece of a reinforcing material. In one embodiment, the sheet would extend from the front panel at a location above the attachment location of the side gussets, over the bottom gusset and onto the rear panel to location above the attachment location of the side gussets. This arrangement is similar to the application of the bottom reinforcement, except that a wider strip of reinforcement is utilized, i.e., one which extends between dotted lines C and D and the sides 212, 214 of the blank 200. This arrangement is advantageous because the gusset side attachment locations, which are a stress point of the folder, would also be reinforced along with the bottom gusset attachment location.

Alternatively, the sheet of reinforcing material can extend along and cover the entire exterior surface of the blank 200 to provide the full exterior reinforcement. In this construction, the bottom gusset, the sides of the front and rear panels where the side gussets are attached, and the top portions of the panel members where tabs, labels or other filing indicia are usually attached are all reinforced. The reinforcing layer serves to strengthen and protect the entire outer surfaces of the folder from wear associated with frequent handling. In addition, the reinforcing layer provides resistance to tearing which can occur when full and/or heavy folders are moved within the file drawer.

The reinforcing material may be made of a wide variety of materials, including paper, cardboard, a plastic film of polyethylene, polypropylene, TYVEK®, or the like. The plastic film may contain natural, synthetic of glass fibers or strands therein to provide further resistance to tearing or wear. The reinforcing material can be simply laminated to the blank prior to folding the appropriate lines therein. The desired reinforcing material can also be applied to the folder using a suitable adhesive, which may be placed either on the reinforcement or on the folder. Also, the reinforcing material can include an adhesive backing to facilitate attachment to the blank. Instead of a single sheet or film, a plurality of reinforcing strips of such materials may be utilized to provide reinforcement in the desired locations. Again, these strips can be secured to the blank by lamination or use of glue or an adhesive.

The application of reinforcement by lamination is easily accomplished by applying the reinforcing material onto the paper using pressure. For this embodiment, the reinforcing material and paper may simply be passed between two rollers which supply the necessary pressure to adhere the materials to each other. It is also possible to apply the reinforcement as a liquid or solution of a polymer or resin which may be cured after application to the paper, if necessary. Other polymer or resin coatings may be used as reinforcement. Moreover, sheets of plastic reinforcement may be extruded directly onto the paper.

Furthermore, when polymeric or plastic materials are used as the reinforcing layer, the folder will be resistant to liquids, such as coffee and water, which may be spilled onto the folder in an office environment when the folder is removed from the file drawer. Yet another advantage can be achieved by using full reinforcement of a clear plastic or polymeric layer on the outermost panel members so that the panel members can be pigmented or colored more easily and inexpensively than prior folders, because the reinforcing material protects the pigmented or colored portions so that less expensive pigments, colorants, or dyes can be used. In addition, less expensive methods can be used for applying such pigments, colorants and dyes. Also, colored reinforcement can be used to impart the desired color to the folder.

FIG. 21 shows a side gusset 220 that is used with the blank 200 of FIG. 20. This gusset is made of a material which is resistant to tearing or ripping, such as a plastic film of polyethylene, polypropylene, TYVEK®, or the like. The plastic film may contain natural, synthetic of glass fibers or strands therein to provide further resistance to tearing or wear. In addition, the gusset can be made of a plastic coated paper composite or laminate.

The side gusset of FIG. 21 has a multiplicity of vertical depressions 222 which are folded or creased to form the gusset folds that are used to expand the folder to receive larger amounts or quantities of paper. Previous non-reinforced gussets were prone to failure at these fold lines, due to the paper tearing along the fold line during extended expanding and collapsing. As noted above, the reinforcement of this gusset 220 substantially increases the useful life of the folder, because the paper does not break or tear at the fold line as it can when it is not reinforced as described herein. The side gusset of FIG. 21 can also be utilized to reinforce the side gusset of a conventional folder. This gusset 220 can be attached to the panel members of any folder after the conventional gusset is attached. For a five piece folder construction, the gusset 220 can be attached to the outer surfaces of the inner panel members after attachment of the conventional gusset. Other arrangements can be devised in accordance with the teachings of the alternative embodiments of the present invention.

The end portions 230 of the side gusset can be of standard width, i.e., substantially the same width as the gusset folds, or of double width as described above for additional strength when attached to the panels. For the specific blank of FIG. 20, it is preferred to have the end portions of the side gussets attached to the outer sides of the panel members upon the reinforcement. Two of these side gussets are utilized for each blank to form the folder. These end portions 230 can be applied to the panel members using a suitable adhesive, which may be placed either on the end portions or the panel members. Also, the side gusset end portions 230 can include an adhesive backing to facilitate attachment to the sides of the panel members. Although it is preferred to apply the end portions to the outside of the panel members, they can instead be attached to the inside of the panel members for certain folder designs.

In one arrangement, the corners where the bottom of the side gusset meets the bottom gusset are not connected, and the folder resulting form this construction is shown as 240 in FIG. 22. Although this construction is acceptable for certain expandable folders, it is preferred to connect these components at the corner junction as well as to reinforce the resulting connection. One connection can be made by simply extending the length of the side gusset, forming tabs 224 by cutting the end portions of the side gusset along the lines 226 shown in FIG. 21, folding the side gusset bottom along the dotted line 228 which extends between the cuts, attaching the tabs to the panel members and attaching the lower portion 232 of the side gusset which extends between the tabs to the bottom gusset. As noted above, the tabs 224 and lower portion 232 of the side gusset 220 can be attached to the panel members and bottom gusset with glue or an adhesive, which may be applied to either component.

Alternatively, the corner reinforcement can be made by adding a separate piece or strip of reinforcement material which extends from the side gusset to the bottom gusset and partially onto the panel members. This corner reinforcement can be made of a material which is resistant to tearing or ripping, such as those described above for use as the side gusset. Preferably, the corner reinforcement is made of a plastic coated paper composite or laminate which and is applied with glue or an adhesive.

The most preferred folder construction 250 for the integral blank embodiment is shown in FIG. 23 wherein like parts to those described in FIGS. 20-22 have been numbered correspondingly. In addition to the full outer reinforcement of the blank and the use of side gussets 220 which include tabs 224 for attachment to the bottom gusset, there are additional features present to further reinforce the folder and achieve an optimum service life. The tops of the side gussets are reinforced with one of the additional constructions 252 of FIGS. 14-19, while the corners of the folder are further reinforced with an additional piece of a plastic coated paper composite 254. To enhance the external appearance of the folder, additional front and rear panel members 256 are secured to the outer surfaces of panel members 202, 206 of the blank 200.

Alternatively, the cover strips can be placed along the sides of the panel members 202, 206 of the blank over the side gusset/panel member connections rather than utilizing the additional panel members 256. In this arrangement, the cover strips can be made of one of the reinforcement materials described above to impart wear resistance to these areas of the folder.

A similar folder can be assembled using the conventional five piece folder construction, i.e., front and back panels, each having inner and outer panel members and being connected by a gusset. In this arrangement, the outer surfaces of the inner front and back panels would include a layer of plastic reinforcement covering the entire outer surfaces. The gusset is preferably made of TYVEK® material laminated paper. It is most advantageous to utilize red wallet as the material for the outer panel members, as well as for the inner front panel member, with the inner rear panel member being made of manilla. The gusset end portions are attached to the reinforcement on the outer surfaces of the inner panel members before attachment of the outer panel members thereto. As noted above, additional reinforcement can be applied to the top of the gusset, the corners of the gusset, the outer surfaces of the outer panel members or the inner surfaces of the inner panel members.

An additional preferred expandable folder 260 is shown in FIGS. 24 and 25, wherein like parts to those described in FIGS. 20-21 have been numbered correspondingly. The outer surface reinforcement 262 of the blank extends from just above the side gusset attachment location 264 on one panel member, across the bottom gusset and onto the other panel member to a location just above where the side gusset is attached. If desired, additional panel members or cover strips can be applied to enhance the appearance of the folder by hiding the side gusset connection 230. Also, the outer surface reinforcement 262 of the blank could be extended to the top of the outer surface of rear panel member 206 to reinforce the area where labels or other filing indicia would be applied and to reduce the likelihood of crushing or bending that top portion of the rear panel member.

A similar folder can again be assembled using the conventional five piece folder construction. In this arrangement, the outer surfaces of the inner front and back panels would include a layer of plastic reinforcement covering the lower outer surfaces as shown in FIG. 24. The gusset is preferably made of TYVEK® material laminated paper, with red wallet as the material of the outer panel members, as well as for the inner front panel member, and with the inner rear panel member being made of manilla. The gusset end portions are attached to the reinforcement on the outer surfaces of the inner panel members before attachment of the outer panel members thereto. As noted above, additional reinforcement can be applied to the top of the gusset, the corners of the gusset, the outer surfaces of the outer panel members or the inner surfaces of the inner panel members.

Although the preferred constructions of FIGS. 22-25 include the attachment of the side gussets to the reinforcement on the outer surface of the blank, it is also possible to make this connection on the inside surface of the blank. In this arrangement, reinforcement material is applied to the inside surface of the blank in the same manner described above for the outer areas. For this embodiment, the previously described blank would simply be reversed, i.e., the outer surface would become the inner surface.

The glues and adhesives of the present invention represent yet another advancement over the current state of the art. Generally, cold glues or adhesives are currently utilized to join the components of a standard expandable folder. Due to the structural modifications of the components of the present invention, such conventional glues are also suitable for use in assembling the present folders. For even greater improvement in the joints between components such as the gussets and panel members, however, hot melt adhesives are preferred. These adhesives effectively seal one component to the other, so that the possibility of failure due to the adhesive joint is essentially eliminated. In most instances, the strength of the joint is greater than the strength of the component.

Another advantageous manner to secure two plastic films together is with the use of a cohesive joint. Again, the strength of the joint is equal to the strength of the plastic material, so that joint failures rarely, if ever, occur without also tearing or damaging the panel members.

Furthermore, the materials utilized for the components of the folders are anther novel aspect of the invention. For example, the panels, gussets and reinforcement can be made of a synthetic paper such as DURALON® (a registered trademark of Arlon, Inc.), which includes a sheet of polyester between two layers of conventional paper. The DURALON® material possesses a high strength and is resistant to tearing. Also, these components can be made entirely from plastic, with the joints made by ultrasonic welding. This construction provides the highest degree of moisture and wear resistance of any of the folder materials mentioned herein. Since the components are welded together, the joint is again as strong as the materials used to make the components. Another advantage when using these improved adhesive and joining systems is that the structural reinforcements described above can be avoided since these features are built into the component materials. Also, gusset end extensions or other joint integrity maintaining means can be eliminated, since the strength of the joints with these systems is essentially equal to that of the materials of the components.

Referring now to FIG. 26, there is illustrated an integral blank 270 which includes a front panel member 272, bottom and side gusset 274 and rear panel member 276 for forming the folder. The back side of the blank, i.e., the side which forms the outer surfaces of the folder, is shown in a flat position prior to creasing the gusset folds 278 and panel member-gusset fold lines 280. This blank 270 can be made of any of the materials described above with respect to the blank 200 of FIG. 20. For expandable folders requiring the greatest strength, the blank 270 can be made of a plastic such as polyethylene, polypropylene, TYVEK®, or the like, or a plastic coated paper composite or laminate.

If paper is used as the material of the blank, a reinforcing layer is provided at least on the outer surface of the gusset and onto the front and side panel members in the same manner described above with respect to the blank 200 of FIG. 20.

Preferably, the reinforcing layer extends along and covers the entire exterior surface of the blank 270 to provide the full exterior reinforcement. This allows the entire folder to be made of plastic or of. a plastic film coated paper laminate or composite. With such materials, even a conventional five piece folder structure has component connections of enhanced strength and increased wear and abrasion resistance. When made out of plastic, the components can be ultrasonically welded to assemble the folder. The side gussets are formed by cutting the blank 270 along lines A, B, C, and D up to their point of intersection with lines 280. After these cuts are made, the folder is formed by making the folds in the gusset, bending the front and rear panel members upwardly by folding line 280, bending the side gussets upwardly by folding along the lines which extend between cuts A-C and B-D, respectively, and then by bending side gusset end portions 282 so that they fold either behind the panel members as shown, or alternatively in front of the panel members, along line 280. These end portions may then be secured to the panel members by glue or an adhesive, by cohesive bonding or by ultrasonic welding, depending upon the material of the blank. FIG. 27 illustrates the final folder after assembly. If desired, the corners of the rear panel member can be rounded by cutting.

Another folder configuration can be achieved by utilizing the same blank 270 of FIG. 26, but with the side gusset end portions 282 being cut out differently. In one alternative, these end portions 282 can be cut along lines 280 from the sides of the blank 270 to the junction with lines A, B, C, and D, respectively. The folder is then formed by making the folds in the gusset, bending the front and rear panel members upwardly by folding line 280, bending the side gussets upwardly by folding along the lines which extend between A-C and B-D, respectively, attaching the side gussets to the panel members by use of an adhesive or other means, bending the end portions 282 along lines A, B, C, and D, respectively, so that they extend around the outside of the side gussets, and then by attaching these end portions 282 to the outer surface panel members by glue or an adhesive, by cohesive bonding or by ultrasonic welding, depending upon the material of the blank.

In this arrangement, the side gussets are protected by two end portions, which do not have to be attached to the side gusset. Advantageously, the end portions can be provided with folds that correspond to the folds 278 of the side gusset 274. If desired, an adhesive can be used to attach the end portions to the side gusset. Since the height of the panel members is generally greater than the width of the side gusset, the end portions will be taller than the side gusset. To remedy this difference, the corners of the blank can be cut away so that the heights of both the side gusset and the end portions will be the same.

Yet another folder configuration can be achieved by utilizing the same blank 270 of FIG. 26, but with some of the side gusset end portions 282 being cut out differently. In one of these alternatives, two end portions 282 can be cut along lines A and D, while the two remaining end portions can be cut along lines 280 from the sides of the blank 270 to the junction with lines B and C, respectively. The folder is then formed by making the folds in the gusset, bending the front and rear panel members upwardly by folding line 280, bending the side gussets upwardly by folding along the lines which extend between A-C and B-D, respectively, attaching the side gussets and first end portions to the panel members by use of an adhesive or other means, bending the remaining end portions 282 along lines B and C, respectively, so that they extend around the outside of the side gussets, and then by attaching these remaining end portions 282 to the outer surface panel members by glue or an adhesive, by cohesive bonding or by ultrasonic welding, depending upon the material of the blank. In this arrangement, each side gusset is protected by one end portion, while the other end portions are attached to the outer surfaces of the panel members. As above, the end portions which protect the side gussets can be in spaced adjacent relation or attached to the side gusset. If desired, two corners of the blank can be cut away so that the heights of both the side gusset and the protective end portions will be the same.

FIG. 28 illustrates another embodiment of the one-piece folder. In this arrangement, the gusset end portions 286 are reduced in size by cutting a portion away along line E. While only one corner of the blank 290 is illustrated in FIG. 28, it is understood that each corner of the blank would be treated in the same fashion. The gusset end portions can be of standard width, i.e., substantially the same width as the gusset folds, or of double width as described above for additional strength when attached to the panel members. If an all plastic construction is used, these end portions 286 can be attached either to the outer or inner sides of the panel members. Where a plastic/paper laminate or composite is used, the gusset should be attached so that plastic is joined to plastic for optimum joint strength. The final folder for this embodiment is shown in FIG. 29.

When the folder of FIG. 29 is made from a relatively inexpensive material such as paper, the side gusset 220 of FIG. 21 can also be utilized to reinforce the side gusset 274 of the folder. This gusset 220 can be attached to the panel members after the side gusset 274 is attached. As noted above, other arrangements can be devised in accordance with the teachings of the alternative embodiments of the present invention.

For aesthetic purposes, the outer sides of the panel members of the folders of FIGS. 27 and 29, as well as the alternative embodiments of those FIGS., may be provided with the cover strips described above or by additional panel members which are secured thereto.

Expandable folders formed according to this invention provide a number of advantages to the user. Various types of reinforcement are provided about and, preferably, over the top of the gusset to prevent tearing or other failure when the folder is overstuffed with file materials. In addition, the end portions of the gussets along the sides and, where applicable, the bottom, have a width which is at least twice the width of the gusset folds to provide a more secure joint with the panel members, which joint is capable of providing increased resistance to tearing away or otherwise separating from the panel members. The outer surfaces of the inner front and rear panel members are also reinforced to strengthen the folder at least in the areas where the gusset is attached, and, for best results, on the entire outer surfaces of the panels.

If desired, the corners of the gusset may be reinforced to prevent wearing due to abrasion with file drawer or work surfaces such as would be caused by sliding the file bottom across those surfaces. It is also possible to reinforce or coat the surfaces of the outer front and rear panel members in critical areas which are subject to stress, wear or abrasion.

For an optimum construction, substantially all outer surfaces of the folder are provided with reinforcement to prevent degradation from moisture or other contaminants. Such outer reinforcement also allows less expensive pigmentation or colorants to be utilized on the paper substrate. The edges of the inner front and rear panel members can be reinforced at the areas where the gusset is attached to further prevent tearing or detachment. All these advantages add to the durability of the file and prolongs its useful life. The strength and resistance to tearing of expandable folder 10 according to the present invention was compared to other expandable folders available on the market. The following test results clearly and unequivocally demonstrate the superior durability and enhanced strength of the expandable folder of the present invention.

FRONT AND REAR PANEL MEMBER PULL TEST This first test demonstrates the enhanced resistance to tearing of gusset 14 from front panel member 11 or rear panel member 12 when folder 10 is stretched after gusset 14 is already fully expanded.

In this test, a rectangular metal box with a hinged top was fit into different types of expandable folders. The box was as wide as the folders when the folders were fully expanded and was as long as the distance between the points of connection of the gusset with the front and rear panel members. A pull ring was attached to the top of the box, which extended out of the folder, opposite the hinge, and a scale was attached to the pull ring.

A pulling force was then applied to the pull ring through the scale. This pulling force opened the top of the box and pulled the front panel member and rear panel member away from the gusset, thereby simulating hyper-expansion of the folder. The folders were considered to have failed when the gusset separated from the front or rear panel member, and the force required to cause the failure was measured with the scale.

The results of this test are tabulated below:

CORNER RUB TEST The corner rub test demonstrates the increased wear resistance of corner 22 of folder 10.

In this test, various expandable folders were filled with nine pounds of paper. An oscillating arm rubbed the loaded folder with an abrasive crocus cloth at a rate of 654 strokes per hour and at a fifteen degree angle with respect to the bottom of the folder. The cloth was changed every 2500 cycles. The folders were considered to have failed when a hole appeared in the corner.

The results of the test are tabulated below:

DROP TEST

This test demonstrates the enhanced load bearing capacity and improved loaded performance of folder 10.

Various folders were filled with ten pounds of paper and dropped from a height of four feet. The folders were dropped on the gussets, on the corners, on the front panel member, and on the rear panel member. The folders were considered to have failed when they split or tore.

The results of the test are tabulated below:

REPEATED MECHANICAL OPENINGS This test demonstrates the enhanced durability in use of folder 10.

An arm which had two diametrically opposed cams thereon was supported between two leaf springs. Attached to each spring was a plate that was as high as the front and rear panel member and as long as the distance between the points of connection of the gusset with the front and rear panel member.

This apparatus was placed inside different types of expandable folders with the plates flush against the front and rear panel members. The low portions of the cam lobes were against the leaf springs when the expandable folder was in its relaxed position.

The arm was then rotated at a rate of 9.6 revolutions per minute, thereby causing the cam lobes to open and close the springs 19.2 times per minute. The springs, through the plates, thereby fully expanded and relaxed the expandable folder to simulate use of the folder. The folders were considered to have failed when the gussets separated from the front or rear panel member.

The results of the tests are tabulated below:

GUSSET PULL TEST This test demonstrates the enhanced resistance to separation of gusset 14 from the front or rear panel members 11, 12 when a pulling force is applied to gusset 14 in a direction parallel to the front or rear panel member 11, 12.

In this test, various types of expandable folders were filled to capacity. A clamp was then attached to the upper edge of the fully expanded gusset, and a pull ring was attached to the clamp through a scale.

A pulling force which pulled the gusset away from the panel member was then applied to the gusset through the pull ring. The folder was considered to have failed when the gusset tore or was pulled away from the front or rear panel member. The force required to cause the failure was measured with the scale.

The results of this test are tabulated below:

GUSSET TEAR TEST The gusset tear test demonstrated the increased resistance to tearing of gusset 14. This test employed a method and apparatus known as the Elmeήdorf-type method to measure the internal tearing resistance of paper. The Elmendorf method measures the force perpendicular to a plane of paper that is required to tear sheets of paper through a specified distance after a tear has been started. A complete description of the method and apparatus is disclosed in TAPP1 T 414 Test Methods. Vol. 1, pages . 1-6 (1991) , which is incorporated herein by reference.

The results of the test are tabulated below:

Accordingly, the above tests demonstrate the greatly enhanced durability, strength, and resistance to tearing of the expandable folder of the present invention as compared to other expandable folders. Folder 10 has increased resistance to failure when gusset 14 is hyper-expanded, when it is picked up by either front panel member 11 or rear panel member 12, or when it is dropped. Further, gusset 14 has increased resistance to separation from front panel member 11 or rear panel member 12 when gusset 14 is pulled, and gusset 14 has increased resistance to tearing. Finally, folder 10 has increased resistance to penetration of liquids and corners 22 have increased resistance to wear. Applicants have designed the expandable folder 10 of the present invention to include these features so that its useful life will be significantly prolonged.

While the present invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made thereto. For example, the gusset can be reinforced with both an outer and inner reinforcement, or a layer of plastic film can be applied to the gusset after assembly of the folder as reinforcement.

It is also contemplated by the present invention that reinforcements 20, 21, 24, 27, 28, 29, 30 be used with other types of expandable folders, namely elastic-tie expandable folders, filing jackets, hanging folders, and wallet-type folders. Further, individual compartments or pockets may be formed within folder 10, as disclosed in United States Patent No. 1,698,841.

According to the provisions of the Patent Statutes, we have explained the principle, preferred construction and mode of operation of our invention and have illustrated and described what we now consider to represent its best embodiments. However, it should be understood, that within the scope of the appended claims, the invention may also be practiced otherwise than as specifically illustrated and described.

Claims

THE CLAIMSWe claim:

1. An expandable folder comprising: a front panel member having first and second surfaces, opposed sides and a bottom; a rear panel member having first and second surfaces, opposed sides and a bottom; a gusset member having a top, bottom, opposed sides, and two corners for connecting peripheral portions of the front and rear panel members so that the first surfaces of the panel members face each other to form front and rear inner boundaries of the folder, the bottom and opposed sides of the gusset member respectively connected to the bottom of the front and rear panel members and along at least a portion of the sides thereof; wherein the gusset member comprises a sheet having a plurality of accordion-like folds, with terminal folds of the sheet being wider than the other folds, and the terminal folds are connected to the front and rear panel members to enhance the connection therebetween.

2. An expandable folder, comprising: a front panel member having first and second surfaces; a rear panel member having first and second surfaces; a gusset member connecting peripheral portions of the front and rear panel members so that the first surfaces of the panel members face each other to form, respectively, front and rear inner boundaries of the folder; and interior reinforcing means applied to the first surfaces of the front and rear panel members adjacent to at least part of the connection between the gusset member and panel member peripheral portions for preventing separation of the front and rear panel members from the gusset member when the folder is used.

3. The expandable folder of claim 1 or 2, wherein the gusset member includes reinforcement means extending along at least one top portion of the gusset member to enhance the tear resistance of the gusset member when the folder is used.

4. The expandable folder of claim 1 or 2 which further comprises reinforcing means applied to the gusset member corners and extending along a portion of the side and bottom of the gusset member to enhance the wear resistance of the folder.

5. The expandable folder of claim 1 or 2, wherein each of the front and rear panel members has opposed sides and a bottom, and wherein the gusset member has top, bottom and opposed sides, wherein the bottom sides of the gusset member are respectively connected to the bottom of the front and rear panel members and along at least a portion of the sides thereof, and wherein the reinforcing means extends along part of the sides of the front and rear panel members on the first surfaces thereof.

6. The expandable folder of claim 1 or 2, wherein the gusset member further has an inner surface and an outer surface, and which further comprises reinforcement means affixed to the outer surface of the gusset member to enhance the wear resistance of the folder.

7. The expandable folder of claim 1 or 2, which further comprises a coating on the second surfaces of the front and rear panel members to improve the resistance of the folder to penetration of liquids and to protect the folder from disfigurement.

8. The expandable folder of claim 7, wherein the coating comprises a styrenated acrylic material.

9. An expandable folder comprising: a front panel member having an outer and an inner surface; a rear panel member having an outer and an inner surface; an expandable gusset member including bottom and side gussets for connecting peripheral portions of the front and rear panel members together such that the inner surfaces of the panel members face each other; reinforcing material applied across a portion of each side gusset of the folder and onto a portion of the front and rear panels to strengthen and increase the connection of each side gusset to the panel members and the durability of the folder.

10. The expandable folder of claim 9, wherein the gusset member comprises a sheet having a plurality of accordion-like folds, and terminal end portions which are wider than the folds.

11. The expandable folder of claim 9, wherein the side gusset members include a top edge, and wherein the reinforcing material is applied in the form of a band to the side gusset members at the top edge thereof.

12. The expandable folder of claim 11, wherein the reinforcing material is affixed to the outer surface of the side gussets and onto the outer surfaces of the panel members of the folder.

13. The expandable folder of claim 12, wherein the reinforcing material is applied in the form of a band which extends across the side gusset members and the outer surfaces of the panel members to completely engage the outside perimeter of the entire folder.

14. The expandable folder of claim 12, wherein the reinforcing material completely covers each side gusset member.

15. The expandable folder of claim 11, wherein the reinforcing material is affixed to the inner surface of the side gusset member and onto at least a portion of the inner surfaces of the panel members.

16. The expandable folder of claim 15, wherein the reinforcing material is applied in the form of a band which extends across the side gusset members and the inner surfaces of the panel members to completely engage the inside perimeter of the entire folder.

17. The expandable folder of claim 15, wherein the reinforcing material completely covers each side gusset member.

18. The expandable folder of claim 9, wherein the side gusset members include a top edge, and the reinforcing material comprises reinforcing strips adjacent the top edge of the side gusset member at each connection of the side gusset member to the front and rear panel members.

19. The expandable folder of claim 18, wherein the reinforcing material comprises a first reinforcing strip affixed to each outer layer of the front panel member, extending at an angle over the top edge of the adjacent side gusset member and onto the inner layer of the front panel member, wherein the reinforcing strip extends across the front panel member beyond the width of the terminal ends of the gusset connected thereto; and a second reinforcing strip affixed to each outer layer of the rear panel member, extending at an angle over the top edge of the adjacent side gusset member and affixed to the inner layer of the rear panel member, wherein the reinforcing strip extends across the rear panel member beyond the width of the terminal ends of the gusset connected thereto.

20. The expandable folder of claim 19, wherein the reinforcing strips extend over the side gusset members at an angle of between 30 and 60 degrees.

21. The expandable folder of claim 9, wherein the reinforcing material comprises a thermoplastic film or a thermoplastic film/paper composite.

22. The expandable folder of claim 9, wherein the reinforcing means is applied to the top edge of the side gusset members and onto the front and rear panel members for providing resistance against tearing of the top edge of the side gusset members or separation of the side gusset members from the front and rear panel members when the folder is used.

23. The expandable folder of claim 22, wherein the reinforcing means is prepared by folding the top edge of each side gusset member onto itself to form a double layer of material.

24. The expandable folder of claim 23, wherein each folded top edge is secured to the side gusset member with an adhesive.

25. The expandable folder of claim 22, wherein the reinforcing means comprises a strip of reinforcing material which extends over the top edge of each side gusset member and onto a portion of each side thereof.

26. The expandable folder of claim 22, wherein each side gusset member comprises a thermoplastic film/paper composite and the reinforcing means is prepared by folding the top edge of each side gusset member onto itself to form a four layer composite.

27. The expandable folder of claim 23, wherein the terminal end portions of each side gusset member and reinforcing material are not attached to each other so that each of the two end portions at each end of the side gusset member may be attached to a different panel member surface.

28. The expandable folder of claim 23, wherein the terminal end portions of each side gusset member and reinforcing material are not attached to each other so that each of the three end portions at each end of the side gusset member may be attached to a different panel member surface.

29. The expandable folder of claim 23, wherein the terminal end portions of each side gusset member and reinforcing material are not attached to each other so that each of the four end portions at each end of the side gusset member may be attached to a different panel member surface.

30. An expandable folder comprising: a front panel member having inner and outer surfaces; a rear panel member having inner and outer surfaces; an expandable gusset member for connecting peripheral portions of the front and rear panel members together such that the inner surfaces of the panel members face each other; and reinforcing means applied upon the peripheral portions of the front and rear panel members, wherein the gusset member is attached to the reinforcing means to enhance the tear resistance of the connection between the gusset member and the panel members.

31. The expandable folder of claim 30 wherein the reinforcing means comprises a band of reinforcing material which is applied to a portion of the sides of the outer surfaces of the front and rear panel members.

32. The expandable folder of claim 31 wherein the gusset member comprises a sheet having a plurality of accordion-like folds, and terminal end portions which are wider than the folds, and the band of reinforcing material is at least as wide as the terminal end portions of the gusset member, and wherein the reinforcing means comprises a strip of reinforcing material on each panel member which extends from the bottom to a location above the point of attachment of the gusset member.

33. The expandable folder of claim 31 wherein the reinforcing means comprises a sheet of reinforcing material which substantially covers the entire outer surface of each panel member.

34. The expandable folder of claim 30 wherein the rear panel member has a height which is greater than the front panel member, the reinforcing material comprises a thermoplastic film or a thermoplastic film/paper composite and the side gussets include bottom tab members and a bottom portion for attachment to the bottom gusset.

35. The expandable folder of claim 30 wherein the gusset member forms a bottom gusset, and the front panel member, bottom gusset and rear panel member are integral and are formed from a single blank of material.

36. The expandable folder of claim 35 further comprising side gussets for attachment to the front and rear panel members to form the folder.

37. The expandable folder of claim 63 wherein the single blank of material and the side gussets are each formed of a thermoplastic film or a thermoplastic film/paper composite.

38. The expandable folder of claim 36 wherein the reinforcing means extends from the front panel member across the bottom gusset to the rear panel member.

39. An expandable folder comprising: a front panel member having inner and outer surfaces; a rear panel member having inner and outer surfaces; an expandable gusset including bottom and side gusset members for connecting peripheral portions of the front and rear panel members together such that the inner surfaces of the panel members face each other; and terminal end portions for attachment to one of the panel members or the side gusset members to strengthen and increase the connection of each side gusset to the panel members and the durability of the folder.

40. The expandable folder of claim 39 wherein the front panel member, bottom gusset, side gussets, rear panel member and terminal portions are integral and are formed from a single blank of material.

41. The expandable folder of claim 40 wherein the terminal portions extend from the side gussets and are connected to the panel members.

42. The expandable folder of claim 40 wherein the terminal portions extend from a panel member and across an adjacent side gusset for attachment to the other panel member.

43. The expandable folder of claim 40 wherein four terminal portions are present, two of which extend from the side gussets and are connected to the panel members, and two of which extend from a panel member and across an adjacent side gusset for attachment to the other panel member.

44. The expandable folder of claim 40 wherein the rear panel member has a height which is greater than the front panel member and the single blank of material comprises a thermoplastic film or a thermoplastic film/paper composite.

45. The expandable folder of claim 40 wherein the reinforcing means is applied to at least half of the height of the outer surfaces of the front and rear panel members beneath where the gusset member is attached to enhance the tear resistance of the connection of the gusset member to the panel members.

46. The expandable folder of claim 45 wherein the reinforcing means comprises a sheet of reinforcing material which substantially covers the entire outer surface of each panel member.

47. The expandable folder of claim 46 wherein the gusset member comprises a sheet having a plurality of accordion-like folds, and terminal end portions which are wider than the folds.

48. The expandable folder of claim 46 further comprising an additional panel member which is secured to each reinforcing means on the outer surfaces of the panel members to retain the gusset attachment therebetween.

49. The expandable folder of claim 48 wherein the front panel member and additional panel members are made of red wallet material, the rear panel member is made of manilla paper, the gusset is made of plastic film reinforced paper, the reinforcing means comprises a thermoplastic film or a thermoplastic film/paper composite, and the rear panel member has a height which is greater than the front panel member for viewing the top portion thereof.