US 3261267 A
Description (OCR text may contain errors)
A. F- BECKER I Jilly 19, 1966 BAGS 3 Sheets-Sheet 1 Original Filed March 11, 1963 FIG.2.
M F. Balm, W, JMLal/L, PM M M,
Q July 19, 1966 A. F. BECKER v 3,261,267
Original Filed March 11, 1963 5 Sheets- Sheet 2 FIGS.
A. F. BECKER July 19, 1966 BAGS 3 Sheets-Sheet 5 Original Filed March 11, 1963 United States Patent BAGS Arnold F. Becker, San Pedro, Califi, assignor t o Bemis Company, Inc., a corporation of Missouri Original application Mar. 11, 1963, Ser. No. 264,330. Divided and this application Apr. 23, 1965, Ser. No.
3 Claims. (Cl. as-ss This application is a division of my copending application Serial No. 264,330, filed March 11, 1963, now abandoned. This invention relates to bags, and more particularly to methods of manufacturing pasted valve bags (i.e., bags having pasted closures at both ends with a valve at one corner) wherein a valve sleeve is provided at the valve corner.
The invention is especially concerned with the provision in a pasted valve bag (such as a multiwall pasted valve bag) of an inwardly extending valve sleeve comprising a length of flexible plastic tubing, such as polyethylene tubing. Use of such tubing for the valve sleeve is desirable because, being limp, the tubing is readily adapted to become crumpled or folded upon itself or pressed flat to seal itself. However, use of the limp tubing per se presents problems in the manufacture of the bags, the limp tubing per se being difiicult to handle in high-speed bag machinery. Also, when such limp tubing is used per se as a valve sleeve, it offers little resistance to bulging or rounding out of the pasted closure at the valve corner of the bag, which may tend to bulge the sleeve open and prevent it from becoming so crumpled, folded or flattened as tightly to seal itself.
Accordingly, among the several objects of this invention may be noted the provision of a method of manufacturing in quantity production valve bags with a valve sleeve construction comprising a length of limp flexible plastic tubing, such as polyethylene tubing, for example, and the tubing having means associated therewith enabling it to be handled in high-speed bag bottomers for high-speed production; and the provision of a method of manufacturing bags with a valve sleeve construction such as described which functions to reinforce the pasted closure at the valve corner of the bag to minimize bulging or rounding out of the closure at the valve corner, thereby insuring good self-sealing of the sleeve. Other objects and features will be in part apparent and in part pointed out hereinafter.
The invention accordingly comprises the methods hereinafter described, the scope of the invention being indicated in the following claims.
In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,
FIG. 1 is a view showing one end of a paper bag tube as it is opened up in the formation of an end closure and provided with an application of adhesive, and prior to application of a valve sleeve of this invention;
FIG. 2 is a view similar to FIG. 1 showing a valve sleeve of this invention applied to the opened-up 'end closure;
FIG. 3 is a view showing the end closure completed;
FIG. 4 is an enlarged section through the valve corner of the'bag as it appears when filled, taken on a line such as indicated at 4-4 in FIG. 3, the walls of the sleeve being shown spread apart;
FIG. 4A is an enlarged section similar to FIG. 4 and showing the sleeve walls flattened to effect a seal;
FIG. 5 is an enlarged perspective of the reinforced bag sleeve removed from the bag closure;
FIG. 6 is a semidiagrammatic view in elevation illustrating a method of this invention; and
FIG. 7 is a perspective illustrating the FIG. 6 method.
Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
Referring to the drawings, there is indicated at B in FIG. 1 a flat paper bag tube which is to be provided with closures at both ends and a valve at one corner. Usually, this will be a multiwall paper bag tube, i.e., a tube formed of a plurality of paper plies. For convenience, there is illustrated in FIG. 1 only that end of the bag tube where the closure to be formed is to include the valve. As shown therein, this closure is formed by opening up the end of the tube to form first and second inwardly directed end flaps 3 and 5 and first and second side flaps 7 and 9. As will be understood, the first side flap 7 is ultimately to be folded over upon a fold line 11 extending transversely of the tube, and the second side flap 9 is ultimately to be folded over on a fold line 13 extending transversely of the tube to overlie the first side flap 7. A pattern of adhesive generally indicated at 15 is applied to the opened-up flap formation. As shown, adhesive 15 includes a stripe 15a extending across end flap 3, a stripe 15b extending across side flap 9, a relatively short stripe 15c extending endwise across flap 9 to fold line 13, a relatively wide stripe 15d of increased width extending between fold lines 11 and 13 on end flap 5, and an elongate relatively wide portion 15e extending along side flap 7 contiguous with fold line 11.
FIG. 2 shows a reinforced valve sleeve S of this invention applied to end flap 5, which may be referred to as the valve flap. Reinforced sleeve S (see FIG. 5 particularly) is a generally flat sleeve comprising a flexible tubing generally designated 17 and a strip of relatively stiff sheet material 19. Tubing 17 has a first wall 21 and a second wall 23, the outer face of wall 21 being adhered to strip 19 by adhesive layer 25 extending across wall 21 at one end of the sleeve which constitutes its outer end. Tubing 17 is secured to reinforcing strip 19 only adjacent the outer end of valve sleeve S, the inner end of tubing 17 being free of strip 19 as shown in FIG. 5. Tubing 17 may be formed of thin polyethylene of a thickness on the order of one mil (0.001 inch), preferably being of the seamless type formed by extrusion. However, it is to be understood that tubing 17 may be formed by seaming along overlapping side edges. Strip 19 may be formed of paper, for example of lb. basis weight natural kraft paper. Such paper has a thickness on the order of 0.006- 0.007 inch, and is relatively stiff, particularly with respect to the one mil polyethylene which is quite limp or flexible. By securing the outer end portion of wall 21 of the tubing to strip 19, rigidity is given to wall 21 at the outer end of tubing 17 while the inner end portion of tubing 17 is free.
Sleeve S is applied to flap 5 with wall 23 of tubing 17 facing in the direction of flap 5 with its outer end portion overlying flap 5 and its inner end portion projecting inward beyond the inner end edge 26 of flap 5. The width of sleeve S corresponds substantially to the width of the closure to be formed, which, as will be readily understood, is determined by the spacing of fold lines 11 and 13 one from the other. The outer face of wall 23 becomes adhered to flap 5 by the adhesive at 15d which 'extends between fold lines 11 and 13 on end flap 5.- After sleeve S has been applied as shown in FIG. 2, the first side flap 7 is folded over on line 11 upon the sleeve and end flap 3 and is adhered to end flap 3 by adhesive at 150, and to the outer face of strip 19 by adhesive at 152. Finally, the second side flap 9 is folded over on line 13 upon first side flap 7, being adhered to the latter by the adhesive at 15b. The completed closure is shown in FIG. 3, and is generally designated 27. It will be observed from FIG. 3 that the outer end of sleeve S is so positioned that it projects out slightly from under the folded-over side flaps 7 and 9. Sleeve S is adhered to the bag proper, i.e., to flap and the overlying flaps 7 and 9, all around the sleeve by adhesive portions c, 15d, and 15e so as to prevent the contents of the bag from sifting out around the sleeve.
It will be understood that the completed bag (also designated by reference character B in FIGS. 3 and 4) is filled by placing the bag on a filling spout (not shown), the spout extending into plastic tubing 17, and blowing the product with which the bag is to be filled into the bag through the spout. The product is typically a fluent pulverized or granulated product. After the bag has been filled and taken off the spout, the inner end portion of the tubing 17 (which is free of the strip 19) crumples up or folds over or flattens out to seal itself against escape of the contents of the bag. FIG. 4A illustrates this by showing the inner end portion of the tubing flattened out. Strip 19 reinforces or stitfens the closure at the valve corner to tend to prevent it from becoming bulged or rounded out. This has the effect of tautening the tubing 17 laterally, so that wall 23 of the tubing (which faces toward the interior of the bag) is prevented from bulging inward, thereby assuring good self-sealing of the sleeve. While FIG. 4A illustrates an ideally flattened condition of the tubing, it will be understood that the inner end portion of the sleeve may crumple or fold over to effect self-sealing of the tubing.
FIGS. 6 and 7 illustrate a method of this invention according to which a succession of sleeves S is formed, one after another, and each sleeve is inserted in the opened-up flap formation at the valve end of each of a succession of bag tubes being fed through a bag bottoming apparatus (i.e., a well-known type of apparatus used in bag manufacturing for forming pasted closures at the ends of bag tubes). As shown, generally flat polyethylene tubing 17a suitable for tubing 17 is unwound from a roll 31 and guided -by guide rolls 33 to an adhesive applying unit 35 which applies stripes or bands of adhesive a to the outer surface or face of tubing 17a which ultimately forms adhesive layer 25 on wall 21 of tubing 17. The spacing of stripes 25a corresponds to the length of valve sleeve S and stripes 25a extend across the width of generally flat tubing 17a on one face thereof. Unit includes a paster 37 having applicators 39 which apply adhesive to tubing 17a and paste roll 41 which supplies paste to paster 37 from a pan 42, as well known. A doctor roll 43 contacts paste roll 41 to remove excess adhesive.
From the adhesive-applying unit 35, the tubing 17:: passes over a combining roll 45 and thence about guide rolls 47 to a sleeve cutting and inserting unit generally designated 48. This includes a pair of draw rolls 49, a sleeve cutter comprising a rotary cutter blade 51 and a stationary blade 53, accelerating rolls 55 on the exit side of the cutter for accelerating sleeves cut by the cutter, and a gripper roll 57 for gripping sleeves exiting from rolls 55 and delivering them to the bag tubes being fed through the bag bottoming apparatus. Unit 48 is part of the latter, and its construction is known to those skilled in the art.
A strip of paper 19a suitable for reinforcing strip 19 is unwound from roll 59 and fed over guide roll 61 to combining roll 45. Strip 19a and tubing 17a become superimposed at combining roll 45 with their side edges substa ttially in register. As the superimposed strip 19a and tubing 17a travel about rolls 47, strip 1% becomes adhered by stripes of adhesive 25a on the adjacent contacting face of tubing 17a. This forms a continuous reinforced generally flat tubing T having reinforcing paper strip 1% secured at sleeve-length intervals to the adjacent face of tubing 17a. Draw rolls 49 function to draw both tubing 17a and paper strip 19a from rolls 31 and 59 and feed the reinforced tubing T through the cutter 51, 53. The latter functions to cut tubing T on transverse cut lines spaced at sleeve-length intervals to segment the reinforced tubing into individual reinforced valve sleeves S. The cuts are made immediately outward of one of the edges of each stripe 25a extending transversely of the combined tubing and strip. Accelerator rolls 55 speed up the sleeves and deliver them to roll 57 which carries the sleeves around and upward for application to the bag tubes. The bottoming apparatus is of a type in which the opened-up flap formations face downward, and roll 57 brings the sleeves up and around to present the sleeves to the end flaps 5 of the bag tubes with wall 23 of tubing 17 facing upward. It is to be understood that the bottoming apparatus may be of the type in which the opened-up flap formations of the bag tubes face upward instead of downward.
It will be apparent that the free inner end of the plastic tubing 17 can crumple or bunch since it is not secured to reinforcing strip 19. By this arrangement, the advantages of a valve sleeve made of limp plastic tubing are retained while a stiffness is imparted to the valve sleeve by the reinforcing paper strip which allows the sleeves to be easily handled by accelerator rolls 55 and gripper roll 57. As the reinforced paper strip is adhered substantially along its entire length to the bag, the reinforced valve sleeve aids in keeping the upper end of the bag from excessive rounding out or bulging after being filled. It will be apparent that the free inner end of the plastic tubing can easily crumple or bunch to effect sealing since it is not secured to reinforcing strip 19.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.
As various changes could be made in the above methods without departing from. the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
What is claimed is:
1. In the manufacture of pasted valve bags with valve sleeves, the steps of continuously feeding forward continuous flat tubing of relatively limp flexible material having first and second walls joined at the sides of the tubing, continuously feeding forward a continuous strip of relatively stiff material, combining the tubing and the strip with the strip overlying the first wall of the tubing and adhering the strip and the first wall of the tubing together at valve sleeve length intervals along their length in zones which, lengthwise of the strip and tubing, are narrow relative to the valve sleeve length and leaving unadhered portions of the tubing and the strip at intervals along their length, segmenting the combined tubing and strip at valve sleeve length intervals into individual valve sleeves with said segmenting being effected on lines so located that each sleeve comprises a segment of the tubing and a segment of the strip with the segment of the strip and the segment of the tubing adhered together only toward one end of the sleeve on one of said narrow zones and the remainder of the segment of the tubing and the segment of the strip, constituting a major portion of their length, being free of one another to the other end of the sleeve, applying each sleeve to one of the end flaps of an opened-up closure for a pasted valve bag with the portion of the other wall of the tubing segment at said one end of the sleeve overlying the end flap and with the sleeve extending inward from said one end flap, and then completing the closure.
2. In the manufacture of pasted valve bags as set forth in claim 1, the closure being completed by folding over first and second side flaps, and said strip segment being adhered to said side flaps.
3. In the manufacture of pasted valve bags as set forth in claim 1, in which the segmented sleeves are continuously fed toward the opened-up closures of bags for application to the said one end flap of the latter, and the individual sleeves as segmented from the combined tubing and strip are accelerated to space each segmented sleeve from the next successive sleeve prior to application thereof to a respective opened-up closure.
References Cited by the Examiner UNITED STATES PATENTS FRANK'E. BAILEY, Primary Examiner.
BERNARD STICKNEY, Examiner.