US2004041A - Utilization of cellulosic films, sheets, and the like - Google Patents

Description

June 4, 1935. J M DRIVER ZOWLWH UTILIZATION OF CELLULOSE FILMS, SHEETS, AND THE LIKE Filed March 22, 1933 Patented June 4, 1935 UNITED STATES UTILIZATION OF CELLULOSIC FILMS, SHEETS, AND THE LIKE John M. Driver, San Francisco, Calif.

Application March 22,

Claims.

My invention relates to the utilization of various forms of sheet material, films, pellicles, or the like, made from cellulosic bodies, particularly those types of cellulosic films or pellicles of which 5 cellophane is a notable and important example, in the manufacture of bags and similar containers.

These cellulosic films or pellicles, besides being highly transparent, are of an extraordinary nature. They. are tough and at any clean-cut edge of the same they resist tear to a marvelous degree. As they are without fibre, in the sense that such term may be applied to sheets or webs ofvarious other forms of cellulosic material, any break in any edge of the same will develop into a tear anddestroy the value of such material when made into various forms of containersbags and/or the like. In the manufacture of bags it is a common practice to form the sheet or webusually a continuous web-into tubular form. These tubes may be plain or have bellows-folded sides, depending upon the type of bag to be made therefrom. While this tubular bag-making material may be severed in various ways, a common practice heretofore followed in the manufacture of bags is to use a serrated striker blade which cooperates with a fixed edge, which may be the end of the former blade, and effects separation of sections of the materialtubular blanks, for instance-from the continuously formed tube. Notwithstanding the toughness of the material it is, in addition, when ruptured by a blunt or relatively blunt instrument, extremely brittle at the point of rupture, and if a serrated blade is employed, this will produce an edge made up of a number of serrations; in other words, a saw-tooth edge. The root of each separate serration or notch of such saw-tooth edge is a potential tear, and in 'practice, many bags do tear at some point or another along such serrated edge.

It has been proposed to sever sheets of "cellophane and similar transparent cellulosic bodies by sharp cutting implements-usually knives cooperating with an anvil-designed to effect cleancut edges, and it may be said that such severing means is emcient so long as the blade remains sharp. The very nature of the material operated upon, however, tends to blunt such edge and in use, owing to the multiplicity of cuts necessary in passing a continuous web of the material through 50 bag-making machinery, the cuts atthe end of the run are not as clean as the cuts initially made at the start of operations. The use of any such cutting instrument, a knife or the like, necessitates frequent sharpening, and in addition demands a design that will permit ready removal of the cut- 1933, Serial No. 662,178

ting blade and replacement after the same has been sharpened, all of which aifects the capacity and proper operation of such machinery.

In the manufacture of many types of bags, it is desirable that a so-called thumb notch shall be provided at the open end of the same. To produce these thumb notches, the web or sheet of cellulosic stock must be successively apertured at regular intervals, and such operation must be performed at some point between the stock roll and the tube-forming mechanism.

In the manufacture of these and other types of bags, it is desirable that the blanks, tubular or otherwise, be cut from the continuous tube at predetermined points or intervals so that the bags or bag blanks shall be of equal length. To effect this condition, the web is apertured at regular intervals throughout its length in order that the openings thus provided may cooperate with localizing means to maintain the feed in such relation to the severing means that blanks may be severed from the main web or from a tube produced from i such main web at definite and exactly equal distances in the operation of the bag-making machine. When bags are to be formed with thumb notches, the cut to sever the blank may be directly adjacent the aperture designed to produce such thumb notch.

In the formation of bags or containers with bellows-folded sides, one end of the same is folded over and pasted down against one wall to form the bot-tom or end closure. It is known to apply an adhesive to the inner wall surface of the blank subsequently developed into such bag or container in order that the part folded over 3 shall be internally connected so that a proper bottom or end closure may be produced. 'In such end closing operation, however, the bellowsfolded side portions arenot connected and it becomes desirable, to insure their connection by adhesive suitably applied. It has been proposed to aperture one wall portion of a web before the same is folded so that in the final folding such apertured portion will occupy a position with respect to a. line of paste or adhesive, which may enter such apertures and insure the proper securing of the bellows-folded side portions of such bag or other container. In all instances, however, these apertures, openings, cuts, and the like, have been produced by sharp edged instruments which are designed to cut through and remove portions of the web which portions must be subsequently disposed of in order to avoid clogging the machine or becoming associated with pasted seams and the like.

Suction devices, designed to gather these severed bits, have been employed and they are more or less satisfactory, although requiring just so much additional apparatus to the tube-forming and/or bag-making mechanism.

Cellulosic products of a transparent nature, of the character of cellophane or the like. possess other properties which I propose to utilize in carrying my invention into effect.

heat, and I propose to sever the same and aperture it as well by a heated implement. In such melting or fusing, the edges of the material are sealed or welded; the excess material vaporizing and vanishing. To this end my invention comprises the employment of heated instruments designed to perforate, aperture, sever, cut, or otherwise act upon the cellulosic body whereby clean, smooth edges will be produced of a nature in which the material itself, by reason of its meltable quality, seals such edge and precludes the formation of nicks, notches, or breaks in the same. i

It is proposed to employ duplex sections 0 cellophane and similar transparent pellicles or films in the formation of bags or similar containers, in which one sheet, usually the inner one, may be of cellophane or a similar cellulosic body having a water-proof coating, while the outer sheet or ply may be of ordinary "cellophane. In cutting such duplex body or aperturing the same, there is double danger of the same producing an uneven edge subject to tear. In carrying out my invention by the use of a heated cutting instrument, I effect autogenous welding or melting of the two edges, so that they cling together and produce a rounded edge that is complete throughout its extent without nick or notch; thereby avoiding all danger of tearing.

These and other features of my invention are more fully referred to hereinafter, and for a better understanding of the same, reference is made to the accompanying drawing, more or less diagrammatic in character, in which the development of my present invention is brought out, and in which:

Figure 1 represents a portion of a web or sheet of cellophane aprtured or perforated in accordance with one part of my invention and available for use in the manufacture of bags with bellows-folded sides. I

Fig. 2 is a fragmentary view illustrating one form of perforating or aperturing means.

Fig. 3 shows an enlarged view of one of the apertures or perforations to illustrate the rounded edge of the same.

Fig. 4 is an enlarged cross-sectional view of a sheet or film of transparent cellophane showing the rounded edge of the aperture, taken on the line IVIV, Fig. 3.

Fig. 5 is a perspective view of a bag bottom or closure, and

Fig. 6 is a fragmentary perspective view of duplex sheets of cellophane which may be employed in the formation of bags or similar c-ontainers, showing the manner in which the edges of the separate sheets are joined by the heating and melting of the cellulosic body during an aperturing operation; suchview being partly in section.

As before noted-these transparent, cellulosic bodies, of. which "the commercial cellophane is perhaps the best known example, are of a nature thatmay be said to melt under the action This material will fuse, or absorb, or melt under the action of of heat. I utilize this characteristic in carrying my invention into effect.

In Fig. 1, I have shown a portion of a web or sheet of cellulosic material, which may be cellophane, apertured for a particular purpose. In Fig 2, I show means whereby these apertures may be effected. In such figure, A represents a roll over which the web of transparent cellulosic material-for instance the cellophane of commercepasses, and this roll is provided with annular grooves a which may be equidistant and occupy such position with reference to the web of material as the nature of the container or bag to be made therefrom will require. Cooperating with the grooved roll are a series of piercing needles or pins b carried by a roll B;

such needles 01' pins being adjustable in such roll, and the roll being adjustable toward and from the roll A over which the cellulosic material passes so that the longitudinal spacing between the apertures of the respective groups may be changed when desired; depending upon the size of bags to be made, inasmuch as the apertures always occupy a definite position relatively to that portion of the blank which subsequently becomes the closed end of the bag or other container. These needles or pins are heated to an extent sufficient to melt the cellophane or other cellulosic film or web as they enter the same in order that the aperture or perforation so made will have a clean and closely sealed edge. These apertures are intended for the passage of a portion of the adhesive in order that such adhesive may engage the wall behind the same which, in the formation of such end closures, is the inner wall of the folded portion, thereby providing a folded end closure in which all of the folded-over portion is firmly attached to one wall of the bag.

The heated perforating pins or needles employed for forming the aperture 0 are relatively small so that the melting effected by such pins or needles practically consumes the material; rounding the edge of the aperture as indicated at 3:, Figs. 3 and 4 and no waste is produced. Hence, there is no necessity for providing means for gathering material hitherto removed from the web in the formation of these apertures.

In order that various forms of bags and similar containers may be provided with a thumb notch in one wall of the open end of the same, the common practice, as hereinbefore noted, is to aperture the web, usually centrally of the same, and then to out such web or the tube produced therefrom transversely at a certain position relatively to such apertures so that the notched portionappears in the open end of one wall of the bag while the otheredge of such apertures comes at the end which is to be folded over to form the end closure. In lieu of a cutting instrument which, as noted, requires constant adjusting and sharpening to perform its function, with the additional difliculty of dulling and requiringfrequent sharpening and sometimes renewal, I propose to employ a blade or implement of suitable material that will stand a heating operation; the

heat applied being of such a degree that the aperture or severance, instead of being cut from the cellulosic product, and precluding all possibility of tearing the same. If a duplex web is apertured in this manner, the edges of the cellulosic bodies, cellophane for instance, will be autogenously welded, as indicated at m, Fig. 6. In like manner the knife, blade, or other implement designed to sever the tube transversely intoblanks may be heated so that the severing operation is in the nature of a melting of the web with a consequent rounding of the severed edge and sealing of the material constituting the body of the web.

It may be possible to consume the larger pieces removed when cuts such as illustrated at Fig. 6 are effected for the formation of the larger apertures with the curved edge serving as a thumb notch, although it is entirely practicable to remove these pieces by suitable suction apparatus,

The severing members or implements employed for severing the tube transversely into blank sections will be heated in a similar manner, but as such operation merely separates one portion of the tube from another, there are no waste-portions and hence no necessity for providing means for removing the same.

I propose to heat the various cutting members electrically; such members being suitably insulated from their carriers in order that current passing thereto may operate in a well known manner; care being taken to insure that the various contacting parts do not complete a circuit and thereby produce an electric are when performing an aperturing or severing operation, all of which is a mechanical problem that does not enter into the present invention. The purpose of my invention is to provide a sufliciently heated perforator or severing member that will effect the desired melting of the body of the cellophane or other cellulosic film and produce a rounded perfect edge for the opening, in contradistinction to a cutting operation which tends to rupture the body of the material instead of sharply and cleanly dividing the same.

Various means for applying electrically developed heat to the several members may be employed, all of which form no part of my present invention.

Various modifications may be made in carrying out my invention; the essential feature of which is the severance or aperturing of a cellulosic body, such as transparent cellophane and the like, by a melting operation as distinguished from a cutting or breaking operation.

I claim:

1. In the utilization of Cellophane and similar transparent cellulosic bodies in the manufacture of bags and similar containers, forming such material into tubing, and severing such tubing into bag blanks of predetermined length through the instrumentality of heat.

2. In the manufacture of bags and similar containers from multi-ply transparent material of a cellulosic nature, the step which consists in applying a heated instrument to such multi-ply material for the purpose of removing portions thereof at a predetermined area, and autogenously welding said plies at the edges of the aperture thus formed.

3. In the manufacture of bags and similar containers from multi-ply transparent material of a cellulosic nature, the step which consists in ap-,

plying a heated instrument to such multi-ply material for the purpose of removing portions thereof in predetermined areas and at predetermined intervals, and autogenously welding said plies at the edges of the apertures thus formed.

4. In the manufacture of bags of cellulosic material-Cellophane and the likethe method of forming a bottom for said bags which consists in folding an end of the blanks from which such bags are made and securing such folded ends to one wall of said blanks, and connecting together portions at the corners of the folded bag closure by preforming apertures by a heated instrument in one wall portion thereof through which adhesive may flow for contact with an oppositely disposed wall portion whereby the latter may be secured in place.

5. In the manufacture of bags of cellulosic material-Cellophane and the likehaving bellows-folded sides, the method of forming a bottom for said bags which consists in folding an end of the blanks from which such bags are made and securing such folded ends to one wall of said blanks, and connecting together the bellowsfolded portions at the corners of the bag closure by preforming apertures by a heated instrumentin one wall portion thereof through which adhesive may flow for contact with the oppositely disposed bellows-folded wall portion whereby the latter may be secured in place.

JOHN M. DRIVER.

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