US2055030A - Method of making stepped end bags - Google Patents

Description

. 22, E 'HQPPE METHOD OF MAKING STEPPED END BAGS Filed Sept. 21, 1934 2 Sheets-Sheet l Sept. 22, 1936.

Filed Sept. 21, 1934 Sheets-Sheet 2 MOW Patented Sept. 22, 1936 UNITED sTATEs 2,055,030 mrrnon or Maxine s'rnrran man sees Edgar Hoppe, to St. Reg s Amsterdam, Netherlands, Paper Company, New York, N. Y.,

assignor a corporation of Delaware Application September 21, 1934, Serial No. 144,900 In Germany September 29, 1933 3 Claims.

This invention relates to a method of forming multiply bags of paper or other similar material.

It has been proposed to stagger the ends of the individual bags and to enable simultaneous 5 folding and pasting of the stepped ends of the bag by mechanical means. The difliculty of this procedure resides in the fact that the parting lines of the tube do not coincide, thus making it impossible to separate the individual bag ends by a simple cut.

The perforation of the individual paper layers before the formation of the tube heretofore proposed leads to manufacturing troubles due to the significant weakening of the paper layers by perforation, which results in a premature or faulty tearing of the paper. This procedure affords no opportunity of making the individual steps sufliciently wide, especially in the case of the multi-wall bag, to effect a secure pasting of both bag ends. This is due to the fact that the overlapping, which the perforated narrow ends require in view of the transverse staggering of all the paper layers, limits the width of the steps at the narrow sides. I

Such insufficient width of the individual steps at the bag ends, especially in connection with the uneven pulling of the paper tube required for the tearing of the perforation, endangers the correct lapping of the. individual tubes disposed in one another. The transverse staggering results especially in a weakened place at the end of the narrow end flap because it is practically impossible to overlap all paper layers of the narrow end flaps.

All these described disadvantages greatly increase with the increase of the number of the individual tubes, and thus endanger the economical manufacture of the bags acording to the described procedure, notwithstanding the correct principle on which it is based. It is an important object of this invention to eliminate the above described objections.

A cardinal feature of this invention resides in effecting a new cut-out of the ends of the individual tubes, this cut-out not only providing for an advantageous folding of the closure, but also at the same time significantly simplifying it and giving to the method of manufacture a greater security of operation.

According to the invention, which can be applied equally to gusseted or ungusseted bags, the bag end isshaped in such way that the side flaps are staggered, whereas the. steps at the end flaps are entirely eliminated. This results in a narrow end flap consisting of individual layers of equal length which are overlapped-by the stepped wide side flaps, this construction eliminating entirely the weakened place caused by the pre- I viously mentioned method of manufacture. Notwithstanding this improvement the separation of the tube length, which chanical means, does not cause any waste. This is attained by stepping the end of each individual unfolded layer in a double way. It has two different portions of equal length connected with one another by two intermediary steps, which provide the narrow'end flaps.

An individual tube consists of a shortened front flap and extended back flap of the same width and the two above mentionedintermediary steps. These intermediary steps which preferably bisect the distance of both main steps are, therefore, in all individual tubes of equal height. They can, if desired, be eliminated entirely in the middle tube, The end of the finished tube is stepped in such way that on both sides the cutting lines are spaced a certain interval from each other in parallel relation. The intermediary steps must be separated from the front and back stepped portions by cuts up to the edge of the shortest step. This results in the formation of narrow end flaps of equal length for the individual layers, this length being suflicient after the folding to secure the required strength of the bag end because the flap consists of layers, the length of which corresponds to the one of the middle tube, whereas heretofore the weakening commenced at the place where the inner or outer layer ended. This enables increasing the steps of the overlapping layers without weakening the closure at the narrow end flaps since even in the case of the widest steps there is always a suflicient covering of the narrow end flaps by the long side folds.

The length of the end flap may be sufficient for the formation of a valve. Should it prove necessary to provide a special reinforcement. for the valve, this can be easily done by inserting in the valve corner a sleeve which may extend inwardly or outwardly from the valve.

The new bag may be manufactured as follows:

The individual paper: layers are provided with weakening lines, i. e. lines of perforations arranged at intervals corresponding to the bag lengths. These lines of perforations extend transversely of the bag, and are formed after drawing the individual paper layers from the storage rolls and before placing them one over the other.

The perforations extend, however, unlike the former method, not across the whole width of may be effected by methe paper layers, but only over a part of it. The total length of the weakening line is generally somewhat less than the double width of the middle part of the bag. The perforations of the individual paper layers are spaced from each other in stepped order. The layers are pulled then in the usual way in an exact location to one another through the tubing machine in which the multiwall bag tube is folded at the sides and pasted together at the longitudinal seams.

In view of the introduction of the double steps the finished bag tube forms intermediary stops at both ends at which all individual tubes have their edges flush with each other. There exists no necessity to separate these steps in advance in the paper layer from the following bag length by perforation, since they can be separated in a much safer and more convenient manner by a out after the formation of the tube. This cut has the shape of a T and runs parallel to the perforations from the step to the edge of the tube as well as at the beginnig of the middle steps perpendicularly to the perforation at a length corresponding to the shortest step. The perforation is then torn with the aid of a suitable tearing device placed behind and connected with the tubing machine. In this manner'the individual tubes retain collectively considerable strength or solidity up to the moment when the middle steps are cut through, i. e. when the side angles are cut out. This solidity remains notwithstanding the perforation at the front and back side and thus eliminates the liability of early tearing as well as a faulty tearing.

This enables a more radical perforation. Under circumstances the perforations can be even replaced by cutting the respective layers before placing the layers one over the other since the portions lying between them in an entirely unseparated state afford suiiicient security against premature tearing.

The invention is shown by way of illustration in the accompanying drawings, in which:

Figures 1 and l" are top plan views of bag ends in unfolded condition in connection with gusseted and ungusseted bags respectively;

Figure 2 is an end view of a bag in folded state where the limiting lines of the edges at the cross sides are shown by dotted lines;

Figures 3, 3 and 3 are fragmentary end views of three plies respectively showing the cutouts of the ends of the unfolded individual tubes of a three-wall bag with gussets and the folding lines; and

Figure 4 is a fragmentary view of the folded bag tube showing the lines of perforations and the T-shaped cuts.

The ends of the three individual tubes of a three-wall bag are shown by the reference numerals i, 2. and 3. The bag can naturally have a greater number of walls, if desired. The above mentioned ends are folded over one another after the end flaps 4, which consists in this instance of three paper layers of equal length, have been folded inwardly, the folding of the stepped wideside flaps being made inwardly along the line 5, covering the narrow-side flaps in such a way that each step 3 lies over the step 3 of the opposite side of the same tube, 2 on 2, and l on I. The end flaps 4 reach sufficiently far under these parts to secure a strong closure and at the same time to form a valve. There exist no differences of principal nature between the construction illustrated in Figures 1 and 1''; only the shape of the bag bottom naturally changes somewhat in the case of a side gusseted bag.

Figure 2 shows a closed bag end in which dotted lines 6 indicate the distance the narrow end flaps extend inwardly. ,The upper flap 1 of the individual outer tube covers nearly the whole bottom side of the bag and secures thus an excellent closure.

Figures 3, 3'" and 3 show'how the ends of the individual tubes appear in an unfolded state. It is pointed out that these drawings do not show the cut-out of the individual layers before they are placed one over the other, since the individual layers are perforated at 8 only along a part of their width, which portions are intentionally exaggerated. The cuts which are shown in these illustrations by uninterrupted lines are in practice made only after the pasting of the tube, 1. e. after it has passed the tubing machine as shown in Figure 4. It can be seen from this figure that the simultaneous separation of the bag tube lengths shown on Figures 3 and 3 is produced by only two cuts of T shape, each at opposite sides of the bag tube in the finished tube, whereupon the perforations 8 (of which only the upper one is seen on Fig. 4 whereas the perforations 8a and 8b are covered and indicated only by dotted lines) are torn, this tearing resulting in a complete separation of the bag lengths. If the paper is already separated by cuts in advance at the line 8 in the individual tearing is naturally eliminated. From Fig. 4 can be also seen that the new bag can be manufactured in a continuous operation without any waste and that the individual bag tubes after their separation are similar to one another in a reversed way.

The stepped arrangement of the individual tubes results also in stepping of the longitudinal pasted seams which are not seen in the figures.

Figures 3 3 and 3 show further that the edges of the individual tubes are stepped over the whole circumference of the individual tubes with the exception of the middle tube for which usually no steps are necessary. Both lines of perforations 8, 8 of the individual layers shown in Figures 3 and 3 are similarly spaced from each other longitudinally of the bag tube a distance equal to the distance between the shortest and the longest step of the finished-bag tube. The portions It forming the narrow end flaps represent an intermediary step corresponding to the half of this large step, the intermediary step coinciding with the edge of the middle unstepped tube. In the latter one the lines of perforations 8 are in alignment with each other and with the intermediary steps Hi. The dot and dash lines H on Figure 3 show in the given example the narrow-side flaps of a gusseted bag, and the dot and dash line l2 indicates the way in which these flaps are folded at the bag end.

At the places where the perforations 8 adjoin the intermediary steps In a separating cut it is made extending to the edge of the shortest step so as to enable the formation of narrow-end flaps of equal length. The perforation which is covered by the stepped side folds is marked for clearness sake on the Figure 3 by the letters a, b, c, and d. The transverse folds of the bag are indicated on Figure 3 by the reference numeral H.

The invention is not limited to the forms of constructions described above, and can be changed in various respects without departing from the spirit thereof, especially as defined in the appended claims.

paper layers, the

what is claimed is: 2. A method in accordance with claim 1 and l. A method of forming multiply bags which comprising the longitudinal slitting oi the multicomprises pertorating lines partially across a pluply tube at each end of each series of said stepped rality of sheets of paper. superposin: the sheets perforations.

with said perforated lines in stepped relation. 3. A method in accordance with claim 1 in 5 folding the sheets and forming them into a mulwhich the sheets are superposed and the tube is tiply tube and slitting the multiply tube transflattened so that the perforated portion thereof versely of the tube across that portion of its width extends across the middle of the flattened tube where the said perforations do not occur and in and the transverse cuts are across the edges of line with an intermediate portion of said stepped the flattened tube. 10 series, thereafter pulling the tube apart and sep- EDGAR HOPPE. arating the plies alonl said series 0! perforations.

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