US 3217970 A
Description (OCR text may contain errors)
B- P. LOKEY MULTI-WALL BAG Nov. 16, 1965 2 Sheets-Sheet 1 Filed May 11, 1964 INVENTOR. Bur/re P. Lo/rey BY ATTORNEY B. P. LOKEY Nov. 16, 1965 MULTI-WALL BAG 2 Sheets-Sheet 2 Filed May 11, 1964 T e m mL IPJ F 5 ATTORNEY United States Patent 3,217,970 MULTI-WALL BAG Burke P. Lokey, Metairie, La, assignor to West Virginia Pulp and Paper Company, New York, N.Y., a corporation of Delaware Filed May 11, 1964, Ser. No. 366,404 9 Claims. (Cl. 229--62) The present invention relates to multi-wall bags and is particularly directed to improvements in bags of the type disclosed in my co-pending application, Serial No. 216,388, filed August 13, 1962.
In the bag disclosed therein, a particular stepped end configuration is provided which permits the formation of strong end closures in a multi-wall, gusseted bag by a simple folding and sealing operation. This bag is, therefore, well suited for use in packaging heavy bulk products by means of automatic packaging apparatus; wherein strength and simplicity of end closure formation is essential. In this bag, in addition to the advantages of strength and simplicity in formation, the ends are so designed that the top and bottom of the bag blanks are identical but reversed in shape; whereby the blanks may be formed from a continuous web of material without waste.
While bags of this type are thus, well suited for the packaging of most materials, it has been found that in the packaging of particularly fine granular materials, liquids and other products that flow quite readily and/ or are easily aerated, some leakage of the product may occur at the juncture of the transverse edge of the bag wall and the longitudinal edge of the adjacent gusset. This results, because at this juncture the complete sealing of the interior of the bag is dependent entirely upon the maintenance of a continuous line of adhesion. Thus, in subsequent handling of the bag, for example, a slight separation of the adhered areas at this corner may occur and cause the formation of a small aperture. While this is of little concern in the packaging of many products, it may permit leakage of liquid products or those of fine granular form, such as activated carbon.
The present invention is designed to prevent this problem and permit the packaging of fine granular or liquid products without leakage and without the use of additional or waste packaging material, but still provide the same strong, easily formed end seals disclosed in my said co-pending application.
In forming the blanks for the bags of the present invention, one or more plies of the blank are shaped slightly differently than the other ply or plies and thus, a small tab of material is provided at the critical point of juncture of the transverse edge of the bag wall and the longitudinal edge of the adjacent gusset. In this manner, rather than the effective sealing of the bag being dependent upon the maintenance of complete adhesion at the bag corners, a positive seal, in the form of a ply of packaging material, is provided at this point. In forming the ply of the bag blank providing these tabs, while the end of the ply is shaped slightly differently than the other ply or plies of the blank to provide this extra tab, each end of the ply is identical but opposite to the other end. Therefore, this ply may be formed from a continuous web with no waste of packaging material and additionally, requires no more material than the other plies of the blank.
While at least one ply of the bag of the present invention is thus, shaped somewhat differently than the other ply or plies thereof, and, differently therefore than the plies of the bag disclosed in my said co-pending application, the overall configuration of the bag is substantially identical. Therefore, the same, simplified folding and sealing operations used to form the ends of the former bag may be used with that of the present invention. A
continuous, multi-ply web of bag blanks formed in the manner of the present invention is, therefore, ideally suited for use in continuous, automatic packaging apparatus where simplicity of forming operations are essential.
The present invention, therefore, provides a multi-wall bag incorporating positive seals in its end closures.
Additionally, the ply or plies providing these seals may be formed from a continuous web of packaging materialwithout Waste of the material.
Further, the formation of the ply or plies providing the end seals requires no more packaging material than the formation of the plies lacking this feature and hence, results in no increase in material costs.
It will also be noted that the closing of the bag incorporating this positive seal may be simply accomplished; thereby rendering the bag ideally suited for use in automatic packaging apparatus.
These and other features and advantages of the present invention will become apparent from the following detailed description wherein:
FIGURE 1 illustrates the manner in which a web of multi-wall bag blanks are formed;
FIGURE 2 is a view of a portion of a web of bag blanks;
FIGURE 3 is an exploded view showing a seal-providing ply of the multi-wall bag blank separated from the other plies thereof;
FIGURE 4 is a view of the assembled bag blank folded into tubular form with the ends of the tube open;
FIGURE 5 is an enlarged view of a portion of the bag showing details of the corner construction thereof; and
FIGURE 6 is another enlarged view of a portion of a bag showing more clearly the manner in which the positive seals are provided at the corners of the bag.
Referring to FIGURE 1 of the drawings, there is therein somewhat schematically illustrated the manner in which a web, in roll form, of multi-wall bag blanks is formed. As therein shown, a plurality of rolls, supplying webs 1, 2, and 3 of packaging material, are placed on unwind stands (not shown) from whence the webs are led through perforators 4, 5 and 6.
Each of the perforators 4, 5 and 6 may conveniently be of the roller type wherein one of the rollers carries a plurality of perforating knives and the other roller a plurality of matching sockets; the knives and sockets being distributed about the periphery of the rollers in a manner such that the desired perforation pattern is impressed on the material passing therebetween. The particular type of perforating equipment used, however, does not form a part of the present invention and any suitable type, therefore, may be used.
As each web passes through its associated perforator, a pattern of perforations is formed therein outlining the shape of the bag ply. Thus, in the present embodiment, perforators 5 and 6 may produce a series of perforations outlining plies 7 and 8 (see FIGURE 3) while perforator 4 may be used to produce the blanks of ply 9. From perforators 4 and 5, respectively, the associated webs 1 and 2 are passed through cross pasting units 10 and 11 where adhesive is applied to the underside of each of the webs at spaced locations. Since it is not necessary to apply adhesive to web 3, it is merely passed around a turning roller 12 and thence, to the combining rolls 13 and 14 where the three webs 1, 2 and 3 are joined to form a laminated web of bag blanks 15. It will be understood that the perforating and combining of the webs 1, 2 and 3 to form the laminated web 15 is suitably regulated to insure that the perforations in each of the webs 1, 2 and 3 are, for the most part aligned, and otherwise correctly positioned relative to one another, to form a laminated web of bag blanks. The laminated web 15 is then led from the combining rollers 13 and 14 to a. rewind stand,
Where it is wound into roll form for convenient storage, shipment and subsequent use. 7
It should be noted that in the formation of the laminated web 15, each of the rolls of packaging material are offset axially of one another to provide the staggered longitudinal edges shown in FIGURE 2. Thus, as shown in FIGURE 2 the longitudinal edge 16 of web 3 may be offset from the longitudinal edge 17 of web 2, which in turn is offset fro-m the longitudinal edge 18 of web 1. Since the Webs are all of constant width, the opposite longitudinal edges, of course, will be offset in a similar but reverse manner.
Turning now to FIGURE 3 of the drawings, there is therein shown a typical bag blank taken from the web of bag blanks shown in FIGURE 2 but with the ply 9 formed from web 1 separated from the plies 7 and 8 to more clearly show the different configuration of the transverse edges of the ply 9 relative to the plies 7 and 8. Plies 7 and 8, which are identical except that the longitudinal edges thereof are displaced relative to one another, each exhibit a front panel 19, a back panel, consisting of two back panel segments and 21, front gussets 22 and back gussets 23. Front gussets 22 are offset longitudinally from front panel 19 to form steps 24 while back gussets 23 are offset from front gussets 22 to form steps 25. Similarly, back panel portions 20 and 21 are offset from back gussets 23 to form steps 26.
Ply 9, except for an important difference which will presently be explained, is quite similar in construction to plies 7 and 8. Thus, ply 9 exhibits a front panel 19, back panel portions 20 and 21, front gussets 22' and back gussets 23. In ply 9, however, rather than the intersections of the longitudinal edges 27 of the back gussets 23 and the transverse edges 28 of back panel portions 20' and 21' forming a step, as in the case of plies 7 and 8, the transverse edges 29 of back gussets 23 are extended to form tabs 30. Similarly, at the juncture of the longitudinal edges 31 of the front gussets 22 with the transverse edge 32 of the front panel 19, tabs 33 are provided for a purpose which will be presently explained. Since the ply 9 is formed from a continuous web without waste between adjacent blanks, the provision of tabs and 33 results in the removal of similarly shaped portions, as at 34 and 35, respectively, from the ends of the blank preceding and following it.
After formation of the Web 15 of multi-wall bag blanks, it may be shipped in this form for use in automatic packaging apparatus. In apparatus of this type, the web is continuously shaped into a gusseted, tubular for-m, filled with the product to be packaged, the filled portion separated from the remainder of the tube along the transverse line of perforations, and the ends folded and sealed to form a filled, sealed bag. Alternatively, if the bag is to be filled and sealed by manual or semi-automatic methods, the web is passed through a tuber and then broken off at the lines of perforations to form a series of open-ended bags for subsequent manual or semi-automatic filling and sealing.
In either case, the resulting bag blank is eventually folded about the parallel, longitudinally extending fold lines 36-38 with the stepped longitudinal edges thereof secured to one another, as shown in FIGURE 4, With gussets 22 and 23 folded inwardly between the front wall panel 19 and back wall panel formed of back wall panel portions 20 and 21. When thus assembled, the removed portions or notches 34 and of the ply 9, which results from the provision of the tabs 33 and 30 on adjacent blanks, are backed by portions of the plies 7 and 8. Hence, the removal of these portions does not affect the sift-proof qualities of the bag. Additionally, since this portion of the bag blank will be folded over to form an end closure of the bag, the loss of one ply at this point in no way affects the overall strength of the bag. However, by the provision of tabs, as at 39 and 33, a positive seal is provided at the corners of the bag.
This is perhaps more clearly shown in FIGURE 5, where the portion of a corner of a folded bag blank containing the tab 33 is shown in more detail. Referring to FIGURES 4-6, it will be apparent that in use, the contents of a filled bag will ordinarily extend within the bag up to the points indicated by the lines aa and bb, where the ends of the bag are folded over to form an end closure. Without the provision of the tabs of the present invention, any separation between the outer surface of the bag and the inner surface of the adjacent gusset, as for example, at point 39, would allow leakage of the package material from the bag. In the bag of the present invention, however, a tab of material, as at 33 in FIGURES 5 and 6, extends as a continuation of front gusset 22 of inner ply 9 around the corner formed by the lower transverse edge of the front wall panel and the longitudinal edge of the front gusset to provide a positive seal at the ends of fold line b-b. Hence, when the ends of a bag, namely those portions above and below, respectively, fold lines aa and bb, are folded over and secured to the rear and forward surfaces, respectively, of the bag, prevention of leakage at points 39 is not dependent on adhesion alone since the tabs 30 and 33 effectively block the passage of material in the bag past these corners even though some separation of the adhered areas occurs.
It will thus be apparent that, through the present invention, a bag incorporating a positive seal at those points wherein leakage is most likely to occur has been provided at no increase in packaging material and without affecting the overall strength and sift-proof qualities of the bag. Additionally, the same strong, easily formed end closures disclosed in my said co-pending application are retained in the present construction.
While for purposes of illustration, a specific embodiment of my invention has been disclosed, certain modifications within the scope of the invention will be apparent to those skilled in the art. For example, the number of plies may be varied to suit the requirements of the particular use contemplated, and plies of the same or different materials may be used as desired. Thus, the present invention is intended to be limited only within the scope of the appended claims.
1. A multi-wall bag comprising:
(a) A plurality of superimposed plies,
(b) each ply comprising a front and back panel, a pair of front gussets and a pair of back gussets,
(0) each of said front and back panels and said front and back gussets being substantially rectangular in configuration,
(d) said front panel joining said front gussets along a common portion of their longitudinal edges with said front gussets being displaced longitudinally of said front panel in a first direction,
(e) said back gussets each being joined to an adjacent front gusset along a common portion of their longitudinal edges with said back gussets being displaced longitudinally of said front gussets in said first direction,
(f) a back panel joining said back gussets along a common portion of their longitudinal edges with said back panel being displaced longitudinally of said back gussets in said first direction,
(g) said front and back gussets of all of said plurality of plies being substantially identical and coincident,
(h) said front and back panels of all of said plies being substantially identical and coincident throughout a major portion of their extent with portions of at least one ply being nonidentical,
(i) said nonidentical portions in said one ply occurring adjacent the intersection of transverse edges of its front panels and back panels with adjacent longitudinal edge of adjacent gussets,
(j) said nonidentical portions of said one ply comprising notches in two adjacent corners of the front panel of said ply and tabs positioned adjacent the other corners of said front panel of said ply, and
(k) notches in two adjacent corners of the back panel of said one ply and tabs positioned adjacent the other corners of said back panel of said ply.
2. The bag of claim 1 wherein:
(a) Said tabs have at least two sides thereof meeting at right angles,
(b) one of said sides of said tab being common to a portion of a transverse edge of a panel, and
(c) the other of said sides of said tab being common to a portion of a longitudinal edge of a gusset.
3. The bag of claim 2 wherein:
(a) Said notches have at least two sides thereof meeting at right angles,
(b) one of said sides extending inwardly towards the center of a panel as a continuation of the transverse edge of an adjacent gusset, and
(c) the other of said sides extending from said one side to the adjacent transverse edge of the panel in which it is formed.
4. The bag of claim 3 wherein:
(a) Said ply having nonidentical portions is the inner ply of the bag.
5. The bag of claim 4 wherein:
(a) Said sides of said notches and said tabs are substantially identical in length.
6. An elongated web of packaging material comprising:
(a) A plurality of superimposed webs bonded together to form a laminated, multi-ply web,
(b) at least one of said superimposed webs having a first pattern of perforations formed therein at constant intervals longitudinally thereof,
(0) the other of said superimposed webs having a second pattern of perforations formed therein at constant intervals longitudinally thereof,
((1) said first and second patterns extending in first and second stepped paths transversely of their associated webs,
(e) each of said patterns comprising pairs of first,
second and third portions and a fourth portion extending perpendicularly to the longitudinal edges of said laminated web and pairs of fifth, sixth and seventh portions extending parallel to said longitudinal edges of said laminated web,
(f) each of said fifth, sixth and seventh portions joining, respectively, a first and second, a second and third, and a third and fourth portion,
(g) said fifth, sixth and seventh portions of each of said patterns being substantially equal in length, (h) said second and third portions of said first pattern being longer than said second and third portions of said second pattern,
(i) said first and fourth portions of said second pattern being longer than said first and fourth portions of said first pattern,
(j) said first and second patterns being substantially identical and coincident throughout a major portion of their extent,
(k) other portions of said first and second patterns being nonidentical, and
(1) those portions of said first pattern which are nonidentical to said second pattern outlining pairs of notches and tabs in the associated superimposed web.
7. The elongated web of claim 6 wherein:
(a) Said tabs and said notches are substantially idenare disposed in spaced parallel relation to each other, and
(b) each of said superimposed webs are of substan tially constant width.
8. The elongated Web of claim 7 wherein:
(a) Said tabs and said notches are substantially identical in shape.
9. The elongated web of claim 8 wherein:
(a) Said tabs are substantially rectangular in shape.
References Cited by the Examiner UNITED STATES PATENTS 392,964 11/1888 McCulla. x.,582,286 1/ 1952 Schenck 229-62 2,757,855 8/ 1956 Allen 229-62 2,875,944 3/1959 Dufiin 229- FRANKLIN T. GARRETT, Primary Examiner.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,217,970 November 16, 1965 Burke P. Lokey It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.
Column 6, line 24, strike out "Said tabs and said notches are substantially iden-" and insert instead The longitudinal edges of said superimposed webs (SEAL) Attest:
ERNEST W. SWIDER Alta-sting Officer EDWARD J. BRENNER Commissioner of Pate s