Expansible Gusset Envelope With Side Flap Seams

Abstract

An expansible gusset envelope having a full front panel and a back panel with side seams all formed from a single paperboard blank. The method of fabrication can either be by hand or machine formed in a continuous operation in which all side and bottom gusset panels are interiorly folded and flattened between the front and back panel at the completion of the operations. In its completed form, the envelope is easily expanded into boxlike configuration by pressing the side and bottom gusset panels outwardly.

Description

This invention relates to an expansible gusset envelope having a full front panel and a back panel with overlying side seams, and more particularly relates to a method for fabricating such envelopes from a single paperboard blank on conventional folding and glueing machines. The instant invention is directed to a method for making a flat-formed gusseted envelope as part of a continuous process during which all side and bottom gussets are interiorly folded between the front and back panels at the completion of the fabrication procedure and wherein the envelope is in flatly formed disposition preparatory to receiving the contents.

In the past, expansible full panel envelopes with gusseted side and bottom panels required a separate and independent procedure to bend in the bottom gusset as a final step during the operational procedure. That is, while the prior envelopes were formed from a single blank, only the side gussets were inwardly formed during ordinary machine operations, and the step of inwardly folding the bottom gusset usually was accomplished by hand in a separate and distinct independent operation. The bottom gusset was not completed during the machine operation, but instead was formed as an outwardly extending "V" projecting front and back panels. See for example, U.S. Pat. No. 2,899,874 in which the additional step of tucking in the "V" required a relatively expensive and time consuming operation.

In my prior patent, No. 3,414,185, I showed an expansible center seam type en e envelope made from a single blank in which all side and bottom gussets were interiorly formed as part of a single continuous machine or hand operation. In my prior application, Ser. No. 703,663, filed Feb. 7, 1968, there is demonstrated a blank from which an expansible full back and front panel envelope can be formed with all side and bottom gussets inwardly formed at the completion of the machine operation.

It is an object of the present invention to form an expansible gusset envelope with a side seamed back panel all in a single continuous operational procedure in which all side and bottom gussets are inwardly bent at the completion of regular machine fabrication.

Another object of this invention is to provide an expansible gusset envelope in which the corners are completely closed and sealed when the gussets are tucked in during the machine folding operations.

Yet another object of this invention is to provide a method for fabricating an expansible envelope from a single blank wherein all gusset sections are inwardly folded at the completion of the forming operation and wherein the envelope can be expanded into boxlike configuration by pressing the gusset section outwardly.

Other objects of this invention are to provide an improved device of the character described which is sturdy in construction, easily and economically produced, and both highly efficient and effective in operation.

With the above and related objects in view, this invention consists of the details of construction and combination of parts as will be more fully understood from the following detailed description when read in conjunction with the following drawings in which:

FIG. 1 is a plan view of a paperboard blank from which an expansible envelope embodying this invention is formed.

FIG. 2 is a perspective view of the blank in partly folded disposition showing the first step of the operation in which the back flap is folded inwardly, then outwardly and next inwardly about its gusset fold lines into overlying disposition with the front flap.

FIG. 3 is a perspective view of the blank showing the next step of inwardly, then outwardly and then inwardly folding the side gussets about the gusset triple score lines.

FIG. 4 is a perspective view of the final step of the folding operation in which the side flaps are folded in overlapping disposition with the back panel.

FIG. 5 is a sectional view taken along lines 5-5 of FIG. 4.

FIG. 6 is a sectional view taken along lines 6-6 of FIG. 4.

FIG. 7 is a fragmentary perspective view of the formed envelope expanded into boxlike configuration.

Referring now in greater detail to the drawings in which similar reference characters refer to similar parts, I show in FIG. 1 a single paperboard blank from which the expansible gusset envelope is to be formed. The blank is so shaped and scored as to enable the formation of the completed envelope on conventional folding equipment, and, at the completion, of the mechanical folding steps, all of the gusset panels will be inwardly folded in concealed interiorly formed configuration. There will be no necessity to bend in the bottom or side gussets by hand after the envelope is folded and glued, and the completed envelope may be conveniently expanded thereafter into boxlike configuration.

The blank itself may be made of paperboard, cardboard, Kraft, manilla or hemp. It comprises a generally rectangular front panel 10 with a back panel 20 connected thereto by bottom gusset sections 12 and 14 defined by triple longitudinal score lines 15, 17 and 19. It is to be observed that the width of the back panel 20 is narrower than the width of the front panel by a dimension at each side equal to the width of a gusset section. In addition, a square notch 16 is cut out of the back panel 20 at each side adjacent the score line 19, the notch 16 having dimensions equal to the width of a gusset section. As will be apparent from the folding operation hereinafter to be described, the notch provides a relief for the glueing and sealing procedure.

Side flap panels 22 are connected to the lateral edges of the front panel 10 along lateral triple score lines 21, 23 and 25. The lateral score lines 21 and 23 define an interior side gusset panel 24 therebetween, and the lateral score lines 23 and 25 define therebetween, an exterior side gusset panel 26. Registering with each of the interior side gusset panels 24 at the lateral edges of the interior bottom gusset section 12 is a rectangular tab 28 having a diagonal score 29 formed therein. A square extension flap 30 at the bottom of each of the exterior side gusset panels 26 is connected to each of the tabs 28 along intermediate score lines 23 also in line with the interior bottom gusset section 12. A diagonal score 31 is formed in each of the extension flap portions 30. Finally, a rectangular tailpiece 32 is connected to the bottom of each side flap panel 22 and along the exterior lateral score line 25 in registration with the interior bottom gusset section 12. A portion of the tailpiece 32 is destined to overlie the square notch 10 when the panels 20 and 22 are fully folded into glued disposition with their underlying portions.

A top sealing flap 40, if desired, may be connected to the upper edge of the front panel 10 along a single longitudinal score line 41 or a series of triple score lines (not shown). However, the top flap 40 is not an integral portion of the invention and is merely demonstrated to illustrate the versatility of the envelope in regard to the folding operation. The procedure for forming the expansible envelope of the instant invention is apparent from the following description.

With the blank oriented as shown in FIG. 1, it is folded by hand or in an envelope forming machine by movement in a direction along the longitudinal fold lines 15, 17, 19 and 41. As shown in FIG. 2, the bottom gusset section 12 is first inwardly formed by folding along interior longitudinal score line 15. Next, the bottom gusset section 14 is outwardly formed by folding along intermediate score line 17. Then, the back panel 20 is formed in overlying disposition with the front panel 10 by folding along exterior longitudinal score line 19.

Thereafter, glue is applied to the lateral margins of the back panel 20 and to the lateral edges of the side flap panels 22. In addition, dabs of glue are applied to the now upwardly folded tabs 28, extensions 30 and tailpieces 32. In a machine operation, the side gussets are now formed by movement in a direction along the lateral score lines 21, 23 and 25. As shown in FIG. 3, the interior side gusset 24 is inwardly formed by interiorly folding along interior lateral score lines 21. Next, the exterior side gussets 26 are out outwardly formed by folding along score lines 23 into overlying disposition with the interior side gussets 24, the tabs 28 being urged into abutment with an area of the interior bottom gusset 12 which is wider than the exterior bottom gusset 4 by a dimension equal to the width of the side gusset 24 or 26. Then, the side flap panels 22 are folded along the exterior score lines 25 so that the lateral edges of the side flap panels are sealed against the lateral edges of the back panel 20. In this orientation, the extensions 30 are sealed against the overlying inner portions of the tailpieces 32 while the exterior portions 32a of the tailpieces are sealed against the underlying interior outermost portion of the gusset sections 14 exposed by the notches 16.

As shown in FIGS. 4, 5 and 6, the bottom gussets 12 and 14 and the side gussets 24 and 26 are all inwardly formed. In addition, the bottom corners of the envelope have been securely closed and adhered into face to face orientation when the tabs 28, the extensions 30 and the tailpieces 32 have been pressed flat between the respective underlying and overlying portions. The upper sealing flap 40 is not folded nor sealed during the fabrication procedure.

Referring now to FIG. 7, by opening out the side gussets 24 and 26 and pressing down from the inside of the envelope upon the bottom gusset sections 12 and 14, the tabs 28 and the extensions 30 will "break" along their respective diagonal score lines 29 and 31. All of the corners are fully adhesively sealed to prevent the contents from accidentally leaking out when the envelope is either folded flat or opened into boxlike disposition.

However, as has been previously set forth, the significant advancements provided by the instant invention are in the configuration of the blank and in the manner of inwardly, then outwardly, and finally inwardly folding the bottom and side gussets along the respective triple score lines. These folding operations permit both the side and bottom gussets to be inwardly folded interiorly of the front and back panels 10 and 20 during the operational steps of fabricating the expansible envelope.

Claims

I claim:

1. An expansible envelope comprising: a one piece blank including a substantially rectangular front panel, a back panel hingedly depending from the lower edge of said front panel by inboard and outboard bottom gusset sections defined by longitudinally extending triple score lines, an inboard side gusset panel hinged to each or the lateral edges of said front panel along corresponding inboard laterally extending score lines, a tab coextensive with and hinged to the lower edge of each of the inboard side gusset panels along extensions of the inboard longitudinal score line and being further hinged to the lateral edges of said inboard bottom gusset section along extensions of the inboard lateral score lines, an outboard side gusset panel to the lateral edge of each of said inboard side gusset panels along a corresponding intermediate lateral score line, an extension flap substantially coextensive with and hinged to the lower edge of each of said outboard side gusset panels along extensions of said inboard longitudinally extending score line and being being further hinged to the lateral edge of each of said tabs along extensions of said intermediate lateral score lines, a side flap panel section hinged to the lateral edges of each of said outboard side gusset panels along a corresponding outboard laterally extending score line, and a rectangular tailpiece hinged to the lower edge of each of said side flap panel sections along extensions of the inboard longitudinally extending score line and being further hinged to the lateral edge of each of said extension flaps along extensions of said outboard laterally extending score lines, said back panel being narrower in width than said front panel by a dimension at each side substantially equal to the width of a side gusset panel and having a square notch at each side adjacent the outboard longitudinal score line equal to the width of a side gusset panel, said inboard bottom gusset section, said tabs, said extension flaps and said tailpieces being inwardly folded along the corresponding inboard longitudinally extending score line, said outboard bottom gusset section being outwardly folded along the intermediate longitudinally extending score line, and said back panel being folded into overlying disposition with said front panel along said outboard longitudinally extending score line, said inboard side gusset panels and said tabs being inwardly folded along the corresponding inboard laterally extending score line, said outboard side gusset panels and said extension flaps being outwardly folded along the corresponding intermediate laterally extending score lines, and said side flap panel sections and said tailpieces being inwardly folded along the corresponding outboard laterally extending score line, said side flap panel sections being adhesively sealed to the lateral margins of said back panel, said tabs being adhesively sealed to the underlying area of the outer margins of said inboard bottom gusset sections, portions of said tailpieces being adhesively sealed to the underlying extension flaps, and portions of the tailpieces being adhesively sealed to the underlying portion of the outboard bottom gusset sections exposed by said notches.

2. The expansible envelope of claim 1 including a top sealing flap hinged to the upper portion of said front panel.