US2013672A - Improved method of making bags - Google Patents

Description

Sept. 10, ROYAL IMPROVED METHOD OF MAKING BAGS Filed June-l5, 1951 2 Sheets-Sheet 1 Sept. 10, 1935. 'r. M. ROYAL IMPROVED METHOD OF MfUHNG B AGS Filed June 13, 1931 r 2 Sheets-Sheet 2- Patented Sept. 1 0, 1935 UNITED STATES PATENT OFFICE 2,013,672" IMPROVED METHOD or MAKING BAGS Thomas M. Royal, Philadelphia, Pa. I

Application June 13, 1931, Serial No. 544,080

5 Claims.

My invention relates to the manufacture of bags and analogous containers of paper and similar material of the type usually produced upon bag machines. Paper bags and the like, ordi- 5 narily produced by the operation of automatic machines,-are made from blanks comprising sections of a continuous or continuously formed tube of paper or other material developed in the usual or well-known manner. The ordinary manner of forming these blanks is to separate the same suc-, cessively from such-tube by transverse cuts or breaks effected by a striker blade whose timed operation regulates or determines the length of the blanks. These striker blades are usually so arranged and operated that their action produces blanks in which one wall at each end thereof is longer than the other, and these ends may be substantially straight or the end of one wallportion'may be relatively straight while the ends of the other wall portionmay be curved. In both instances one end of each wall portion of the blank projects beyond the end of the other wall portion, and one of these projecting ends is subsequently folded and pasted down to form a bottom or end closure and thus produce a bag. When one of these ends is curved the convexly curved portion projects at one end while the straight edge portion projects at the opposite end and it is this latter end that is subsequently folded and pasted down to form the bottom. As the striker blade is usually, and inmost instances necessarily, provided with serrations, the end edges of the wall portions of the blank; those at the open end of the finished bag; as well as thoseat the end turned 35 over to form the closure or bottom of the bag, are

serrated. V

In the formation of the bottoms of bags thus made, a-portion of suitable adhesive is usually applied to a face or wall of the bag adjacent to the part to be turned over or upon the latter, and this folded portion is then flattened down and fastened against one wall of the bag by the interposed adhesive. But this mode of fastening the turned portion of the blank to form the bottom closure has never been entirely satisfactory. By

reason of the fact that the adhesive can only be applied to one face of the wall of the blankand usually within the side margins'thereof, unconfined portions are left at the sides of the bag bottom adjacent to the corners thereof, which constitute air gaps.

In the manufacture of bags from cellophane" or similar pellicles or films, it is undesirable to separate the pre-formed tube into blanks by means of a serrated striker blade. In the first place, while cellophane is relatively strong when subjected to strain in either direction it is, nevertheless, more or less fragile and if the fibres are broken or ruptured at any edge ofthe same it can be readily torn or separated at right angles 5 to said edge, usually longitudinally of the blank or the finished bag. If therefore blanks are formed from a tube by severing the latter trans- 'versely of its length by a striker blade having a serrated edge, the fibres of the cellophane are 10 so broken or ruptured by such blade at such serrated edge as to make it possible easily to tear the same at right angles to said edge; a tear being liable to start at any serration and when once started continuing throughout the body of 5 the blank or the. finished bag. Additionally, as the points of the serration are relatively stiff, they interfere with the insertion of many goods. These cellophane bags or containers of cellophane? with serrated edges can not be used for the pack- 0 v aging of sheer silk stockings, as the points stick in the stockings, pick up stitches and cause runners. Cellophane" bags with serrated edges are also objectionable for many other reasons; one being their unsightliness. If, however, the tube of cellophane is severed into blanks by straight, shear cuts transversely of its longitudinal axis, it is almost impossible to start a tear from such straight out edges. For practical reasons, in the formation of blanks by straight cuts transversely of their length, each wall of the blank is of the same length.

These straight out blanks with each wall of the same length can not be bottomed or closed to form bags'in the usual manner, since the adv hesive applied to retain the folded end employed in forming such bottom closure would only engage adjacent portions of the same face or wall of the bag blank, and as the other wall of the blank would be wholly unconfined, an open end 4 would result. To overcome this objection, I propose to give one end of'the bag blank, which may be a straight, smooth cut end, a double fold, and to permanently secure the second folded portion to one side wall of the same; the inner 5 face of such second portion which adheres to one face or wall of the bag blank being part of the face of the opposite side or wall of the bag. Preferably, both ,folded portions will be secured by lines of adhesive, suitably applied.

These and other features of my invention are more fully described hereinafter; reference be-- ing had to the accompanying drawingsymore or less diagrammaticin character, in which;

Figure 1 is a side elevation of sufficient of the mechanism of an automatic bag-making machine to illustrate means which may be employed and successive steps in the manufacture of my improved double-folded-bottom bags.

Fig. 2 is a plan view of a portion of the mechanism illustrated in Fig. l; the upper rolls being omitted.

Fig. 3 is an enlarged diagrammatic view of the means employed for making the first fold and applying adhesive to the blank in the formation of the bottom closure.

Fig. 4 is an enlarged diagrammatic view show ing the first folded end portion of the blank passing between pressing rolls.

Fig. 5 is an enlarged diagrammatic view of the means employed for applying the second fold to the end of the blank and applying adhesive whereby the latter may be secured in place.

Fig. 6 is an enlarged diagrammatic view showing the rolls for pressing down the double-folded bottom.

Fig. 7 is a perspective view of a bag blank prepared in accordance with my invention before the same has been formed into a bag; the position of the folds being indicated by dotted lines. and a line of adhesive being indicated.

Fig, 8 is a similar view, illustrating the bag blank after the first bottom fold has been applied thereto.

Fig. 9 is a perspective view of the finished bag.

taken on the line X-X, Fig. 8, showing the single fold secured by a line of adhesive.

Fig. 11 is a similar cross-sectional view taken cured in place by a second line of adhesive.

Fig. 12 is a cross-sectional view illustrating another type of tube which may be formed into bag blanks, in accordance with i! Fig. 3.3 is a view in elevation illust g other means which may be employed to produce bags with double-folded bottoms, and

Fig. 14 is a plan view of the elements illustrated in Fig. 13; the upper rolls shown therein being omitted.

The common practice in the manufacture of flat bags made of the usual tubing formed by longitudinally folding a continuous web or sheet of material and fastening overlapping edges of the same together by a longitudinal seam, or square bags made from tubing with bellows-folded or plicated sides, is to sever blanks from such tube by means of a striker blade which i moved at regularly timed intervals in a plane transversely of the tube as the latter is carried forward by draft rolls or other means commonly employed in bag machines of the automatic type. The effect of this operation of striker blade with the cooperating parts is to produce blanks having projecting portions at each end of the same; one wall extending beyond the other wall of the blank in alternate relation, with each end edge of said walls serrated. Following this action of the striker blade the forward end of the blank with the projecting endportion of one wall or side of the same is creased and folded or turned over and fastened down by a transverse line of adhesive which is preferably applied to one face or wall of the blank just in advance of the creasing and folding operation; the projecting portion of one wall of such blank engaging such adhesive.

Bags so made usually present an'open end with one wall or side projecting beyond the other, with both edges serrated. While such bags are entire 'ly eflicient for many purposes, the serrated edges is, nevertheless, more or less fragile and if the fibres are broken or ruptured at any edge of the same it can be readily torn or separated at right angles to saidedge, usually longitudinally of the blank or finished bag; such tearing being likely to occur when goods or commodities are being 5 inserted in such bags. If therefore blanks are formed from a tube of cellophane by severing the latter transversely of its length by a striker blade having a serrated edge, the fibres of the cellophane are so broken or ruptured by such blade at such serrated edge as to make it possible to easily tear the same at right angles to said edge; a tear being liable to start at any serration and when once started continuing throughout the body of the blank or the finished bag. Additionally, as the points of the serrated edges are relatively stiif, it is more or less dinicult to insert some types of merchandise, sheer silk stockings, for instance. in these bags or containers; the points of the serrations being sufficiently sharp to catch the threads and cause runs in such stockings, in the operation of packaging the same in cellophane bags or con tainers.

I propose to overcome this difficulty by forming blanks from a tube of cellophane which may be produced in any suitable manner, including formation by an automatic bag machine or otherwise, by successively severing such tube into 7 blanks by smooth, shear cuts applied transversely of the same substantially at right angles to the longitudinal axis of the tube, and to provide bottom or end closures for such blanks by impart ing double folds to one end of the same and securing such folds to a wall of the blank which subsequently forms the bag. Each fold may be secured by a transverse l.'ne of adhesive.

In the drawings, which are largely diagrammatic, A may represent a web of cellophane which may be developed into a tube E, by folding the same along the lines a, whereby one side portion a, of such web is caused to overlie the other side portion 11 thereof; the overlapping portions forming a seam and being secured together by an interposed line of adhesive b applied adjacent to one edge of one side portion of such web.

In carrying out my invention, the tube of cellophane, indicated at B, and which may be formed from the web A in the usual manner common in the operation of automatic bag-making machines or otherwise, may be carried forward by draft rolls land 2 and presented to cutting rolls 3 and 4; the former having a blade 3 extending longitudinally ofthe roll and serv- 5 which creasing blade is adapted to engage the body of the blank adjacent to the forward end thereof and press such end in folded relation between gripping elements carried by .the roll 8 which are presented thereby in open position to receive such folded portion; such gripping elements being subsequently closed and holding the folded end of the bag blank and carrying it forward for subsequent engagement by a 'small pressing roll 9. Just before the folded end of the blank reaches the roll 9 the gripping means carried by the roll 8 are released and the folded end of the bag blank automatically springs out of contact therewith and momentarily occupies a position with the folded end free and ready forpresentation to the small press roll 9 as shown in Fig. 3; the latter roll serving to press the folded 'end of the blank against the transverse line of paste, indicated at a: and previously applied to the face of the blank. The rear portion of the bag blank is still within the bite of the rolls I and 8 and is being advanced thereby before the roll 9 engages the same against the surface of the roll 8, as shown in Fig. 4, and from said rolls 8 and 9 the bag blank with the single bottom fold passes to a second set of bottoming and paste-applying rolls I0.and II which may be of the same character as those indicated at I and 8; the roll l having a paste-applying element I0 and a creasing and tucking blade I0 the latter being adapted to engage the single folded end of the bag blank and press such end in further folded relation between gripping elements of the same type as those carried by the roll 8'; such gripping elements holding the folded end of the bag and carrying it forward for subsequent engagement by a small pressing roll I2. Just before the double-folded end of the blank reaches the roll I2 the gripping means carried by the roll I I, are released and the doublefolded end of the bag automatically springs out of contact therewith and momentarily occupies a position wth the double-folded end free and ready for presentation to the small press roll I2,

as shown in Fig. the latter roll serving to,

press the double-folded end of the bag against the second transverse line of paste, indicated at y and applied to the face of the bag wall, as shown in Fig. 5. From this second bottoming operation the foldedends of the bag blank may be presented to and caught successively b'ygripplng members I3 carried at properly spaced intervals by an endless chain I4, diagrammatically indicated in Fig.

2; be'ng held by such gripping elements until "of the bag, with the lines of pastebetween the same; the second fold when pasted down serving to completely close and seal one end of the blank to form the desired bag. The double-folded end produced in the 'manner described, completely seals the end of the bag and avoids the air gaps at the comers of the bags common to those types of bags having their bottoms formed by a single fold of the material. As clearly shown in F. g. 10, a single fold of the end of the blank is insuificient inasmuch as it leaves one side wall of the bag unconfined; the straight shear cut producing blanks having side walls of the same length throughout; When the second fold is applied, as indicated in Fig. 11, one wall of the bag, which may be indicated at z for convenience, is brought over and'secured to the op.-

posite wall or face of the bag which, for con- 5 indicated in Fig. 12, may be bottomed in a manner precisely similar to the fiat bags illustrated, without departing from my invention.

It will be understood of course that I do not wish to be limited to the use of mechanism such as that illustrated in Figs. 1 and 2, for carrying out the method or process constituting my invention. While such means is well adapted to produce from straight cut blanks the doublebottomed bags forming part of my present inven tion, other means for effecting the same result may be employed, and in Figs. 13 and 14 I have shown a modified arrangement of mechanism which may be employed in the production of bags with double-folded end closures.

In Figs. 1, 2, et seq., I have illustrated the fea tures of my invention in connection with tubing produced upon an automatic bag machine in advance of the blank severing means. It will be understood, however, that my improved bags may be made from preformed tubing, which may be presented to the severing meansv for formation into blanks; such blanks being carried forward for the performance of the' severaloperations necessary to transform the same into bags with double-folded ends, and the mechanism illustrated in Figs. 13 and 14 is shown as operating upon a pre-formed tube of material.

In the operation of the mechanism arranged 40 in the manner illustrated in Figs. 13 and 14, which views are purely diagrammatic, a tube B, previously formed from a web of cellophane," maybe carried forward by draft rollers IM and I02 and presented to cutting means for severing the same into bag blanks, which may comprise a pair of rolls I03and I04; the roll I03 having-a straight cutting blade I03 arranged lengthwise thereof and adapted to cooperate with an anvil I04 carried by the roll I00. The blanks thus formed may then be' presented to a pair of rolls I05 and I06; the former having a paste-applying element Hi5 arranged lengthwise of the same, adjacent to a folding blade I 05; the latter cooperating with gripping means carried by the roll I06, and these elements respectively serve to apply a line of paste transversely of the blank adjacent to one end of the same and impart a fold to said end which is subsequently turned over in the same manner as illustrated in Figs. 1, 2, et seq. The blankwith the single turned end may be carried forward by draft rolls I01 and I00 and pass to rolls I09 and H0, which may be of the same character as the rolls I05 and I06; being provided with cooperative means for creasing and folding the end of the bag blank to form the second fold, and such means may include a folding blade I09 carried by the roll I09 and cooperating with the complemental means carried I by the roll I I0 for securing the final fold in place. i

The roll I09 also carries a paste-applying element I09 which acts after the creasing action by the blade I09. From these latter-rolls, the bag with the double-folded end may be carried forward by a series of draft rolls III and 2 whereby the final fold may be given preliminary pressure against the second line of paste and passed to gripping means which may be the same as those shown in Figs. 1 and 2, for holding the finally folded end of the bag until the paste is set. Such gripping means may be carried by endless chains in the same manner as indicated in Figs. 1 and 2. The bags produced by such mechanism from the pre-formed tube of material, cellophane or the like, may be of a type identical with those illustrated in Figs. '7, 8 and 9.

If these bags are to be printed, the gripping means carried by the endless chains and engagwithout tearing, when goods or commodities of any nature are inserted in the same. It will be understood that while a substantially straight out may be desirable in many instances I may employ blades capable of imparting smooth, clean cuts transversely of the tube in a relatively curved direction, or at an angle which may be other than a right angle.

While I have illustrated in the drawings different forms of mechanism capable of effecting the double fold and sealing the same to the end of a tubular blank for the purpose-of transforming such blank into a bag or container with a closed end or bottom, it will be understood that I do not wish to be limited to any of the mechanisms illustrated, or any part thereof, since any means capable of preparing blanks with smooth edges and effecting the double-folded end closure of the same is within the scope of my invention.

It will be understood of course that I may employ any form of material in the manufacture of my improved bags, and that when cellophane is employed I may use any form thereof; including the wateror moisture-proof type. It is believed that the wateror moisture-proof coating imparts to the cellophane additional strength or resistance to tearing.

I claim:

1. The method of making bags of cellophane and similar material which consists in continuously forming a web or sheet of cellophane or similar material into tubular shape, imparting movement to said tube longitudinally of the same, severing said tube by substantially straight, transverse clean edged cuts into blanks of predeterminedlength, applying lines of adhesive transversely of said blanks adjacent one end of the,

same, imparting a plurality of folds to said end of the blanks, causing said folded portions to engage said lines of adhesive, and successively compressing said folded end portions against such adhesive.

2. The method of making bags of cellophane" and similar material which consists in forming a web or sheet of "cellophane or similar material into tubular shape, severing said tube by straight transverse cuts into blanks of predetermined length, applying a line of adhesive transversely of said blanks adjacent one end of the same, folding said end of the blanks and causing it to engage said line of adhesive, compressing said folded end, applying a second line of adhesive, imparting a second fold to said blanks which includes the first fold, and confining said second fold in place in contact with the second trans verse line of adhesive.

.3. The method of making bags of cellophane and similar material which consists in forming a web or sheet of cellophane or similar material into tubular shape, severing said tube by straight transverse cuts into blanks of predetermined length, applying a line of adhesive transversely of said blanks adjacent one end of the same, simultaneously folding said end of the blanks and causing it to engage said line of adhesive, compressing said folded end, applying a second line of adhesive, simultaneously imparting a second fold to said blanks which includes the first fold, and confining said second fold in place in contact with the second transverse line of adhesive.

4. The method of making a bag of cellophane or similar material which consists in forming a web or sheet of cellophane or similar material into tubular shape, imparting movement to said tube longitudinally of the same, severing said tube by straight, transverse clean edged cuts into a blank, applying a plurality of lines of adhesive in parallel relation transversely of said blank adjacent one end of the same, imparting a double fold'to said end of the blank, causing said folds to engage said lines of adhesive, and finally compressing said folded end into sealing contact with a wall of said blank to complete the bag.

5. The method of making a bag of cellophane or similar material which consists in forming a web orsheet of cellophane or similar material into tubular shape, imparting movement to said tube longitudinally of the same, severing said tube by straight transverse, clean edged cuts into a blank of predetermined length, successively applying lines of adhesive in parallel relation transversely of said blank adjacent one end of the same, successively imparting a double fold to said end of the blank, causing the respective folds to engage said lines of adhesive, and compressing said finally folded end into sealing contact with a wall of said blank to complete the bag.

THOMAS M. ROYAL.

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