US2546059A - Method and apparatus for preparing and using sheet material for packaging purposes - Google Patents

Description

March 20, 1951 w. s. CLOUD 2,546,059

METHOD AND APPARATUS EUR PREPARING AND USING SHEET MATERIAL EUR PACKAGING PURPOSES Filed Aug. 24, 194e IUT NI@ -ing a label to the wrapped article. terial, if printed before used, necessarily will be Patented Mar. 20, 1951 METHOD AND APPARATUS FOR PREPARING AND USING SHEET MATERIAL FOR PACK- AGING PURPOSES William S. Cloud, Wilmette, Ill.

Application August 24, 1946, serial No. 692,878

Claims.

My invention relates to packaging and has to do more particularly with .a new and improved method and apparatus for preparing and using sheet material for packaging purposes.

There has developed in industry a rather widespread demand for a package in which the packaging material conforms closely to the shape and size of the various commodities with which it is used, and at the same time offersa protective covering therefor. Such a package can be formed of any material which can be stretched sufficiently to make one or more pieces of it conform to the article to be wrapped. The rubber hydrochloride product sold by the Goodyear Tire & Rubber Company, Inc., of Akron, Ohio,under the trade name Pliolm is an excellent example of a material which can be' used in stretch-wrapping. (It will be understood by those skilled in the art that stretch-wrapping is a term commonly used in this art to designate wrapping to conform to the article by increasing the area of parts of the wrapping material rather than by folding or crimping it.)

Several methods and machines have been developed to stretch-wrap articles. These fall into two general types or classes. As is illustrated in my Patent No. 2,403,482, one of these types involves exerting pressure in a direction perpendicular to the surface of a sheet of stretchable material, such as heated Plioiilm, to stretch and thus form a pocket in it. After the article has been inserted, thispocket is then closed and sealed by twisting it, and then severed from the excess material. As is disclosed and claimed in my co-pending application, Serial No. 436,666,v

filed March 28, 1942, now abandoned the other type involves making a package from two sheets of stretchable material. Pressure is exerted in a direction perpendicular to the surface of each sheet, to stretch them and form a pocket in each. These pockets are closed together and sealed around the article, and several from each other and from any excess material.

While both of these types result in a package in which the packaging material conforms closely to the shape and size of the articles to be wrapped, in a package which will protect the artlcles and which may be less expensive than the usual package due to the saving of packaging material attending the stretching thereof, they present certain dimculties when it is desired to label the article thus stretch-wrapped, either by printing the wrapping material or by attach- The ma- 2 stretched and the resulting distortion to the printed matter makes it unattractive even when it has not faded to illegibility because of the` stretching. If it is desired to seal or print a label on the wrapped article, difficulty may be encountered due to its irregular shape and also because certain of the stretchable materials, such as P'liolm, do not readily take printing. A further factor involved in the first type of method and machine is that the entire sheet of stretchable material must be printed, which adds appreciably to the cost. While labels might conceivably be inserted into the package with the article to be wrapped, the label would probably be objectionably distorted and the insertion would be a costly procedure. Y

My invention makes possible the labeling of stretch-wrapped articles, While avoiding the diiculties specified above. Other objects and advantages of my invention will appear hereinafter. p

In order to illustrate diagrammatically the respective steps of my invention, I have provided the accompanying drawings in which Figure 1 is a diagrammatic view of an apparatus for practicing my invention, shown in longitudinal vertical section.

Figure 2 is a fragmentary top view of the filling and sealing drum 5, shown in Figure 1.

Figure 3 is a perspective view of packaged article as produced by my invention.

In order to illustrate how my method of preparation sheet material is applicable to a packaging operation, attention is directed to Figure 1, wherein a web l of unprinted, stretchable sheet material, such as Pliolm, is fed or unwound from roll 2 around idler roll 3. Roll 3 guides the web into contact with soap bubbles, created by blowing air through a soap container in a conventional manner, to coat the back of the web with a lm of soap which tends to prevent the web from subsequently sticking to objects with which it comes into contact.

It is to be understood that these anti-sticking measures do not form a necessary part of some aspects of my invention. Certain stretchable sheet materials do not have a marked tendency to stick to other objects; others, such as Pliolm, do. Obviously, stretchable sheet materials which do not have this tendency will not require the use of these measures. Similarly, coating the back of the lm with a nlm of soap is not the only anti-sticking measure available. The lm may also be backed with wax, paper, etc.; or the objects which it Will contact may be surfaced with polished chrome plate or some similar substance, or covered with spun glass sheet, cotton cloth or some similar substance. However, inasmuch as one of the purposes of my invention is to provide a method and apparatus for using Pliolm, some means of preventing sticking is an important part of the preferred form of the invention.

From roll 3, the unprinted web of stretchable material is passed around rolls 4 and thence around iilling and sealing drum 5.

Drum 5 and at least one oi guide rolls 4 are driven in timed relationship by sprocket chains from any suitable source of power (none of which is shown). o

Certain of the web materials which will be used in connection with my invention are normally non-stretchable at room temperature. Some, as, for example, Pliolm, must be heated' to render them stretchable;l others must be chemically treated to render them soft and stretchable. rPhe term stretchable is, of course, relative since any lm will stretch minutely. In Figure l I have illustrated the heating of the web material as it passes around drum 5 by blowing hot air on it. However, it is to be understood both that this is not the only method of heating the web material and that,l in the case of a web materiall which must be chemically treated to render it stretchable, this heating would be omitted and the appropriate chemical treatment substituted. These treatments, designed to render the web material soft and stretchable, may occur before the web materialY is guided onto drum 5. The position shown in Figure l minimizes the danger of having web l adhere to rolls 4.

Filling and sealing drum 5 is constructed in substantially the same manner as drums l and 2 described in my co-pending application, Serial No. 436,666, filed March 29, 19421 For the purposes of this application it is sufiicient to indicate that said construction includes cups or containers i3, generally made roughly the size and shape ofthe articles tobe wrapped, or of the nishedpackage mounted in contact or at predetermined intervals by meansnot shown to form the outer surface of the d-rum. A vacuum chamber 3i is positioned tosupply avacuum to the cups forthat part of the cycle, during which a vacuum is desired. rIfhis chamber is shown diagrammaticallyadjacent the cups, whereas` in practice it would be positioned adjacent the axis.

In Figure l I have illustrated the application of vacuum tothe cups immediately after the web ihas been rendered stretchable by the application of heat thereto. If Web l is of Pliolm, or similar substances, this will have the effect of drawingv the web i into the cups to the bottom or any lesser desired amount which may be obtained by regulating the amount of vacuum. I prefer to hold the vacuum, thus securing the web in the cups, until after the articles to be wrapped have been placed in the cups, and the cups sealed, as will be hereinafter explained. more fully. In wrapping certain light articles in certain web materials which are not only stretchable but also elastic, the vacuum may be necessary to retain the pockets formed by sucking the web into the cups. The web may also be forced into the cups either by plungers or by the articles which are to be Wrapped when the nature of the articles are suitable, in which cases the vacuum could assist, or could merely be used toretain the pockets, if needed at all.

After the web l. has been forced into the cups 6, to form pockets in the web, thesepockets are nlled with the articles to be wrapped. This can be done by hand or by a suitable mechanical device. The choice of the pocket-nlling mechanism will depend to a large extent upon the nature of the articles to be wrapped. In Figure 1 I have illustrated a feeding device suitable for filling the pockets with peanuts or similar articles. A peanut hopper lled with peanuts is suspended above drum 5 so that gravity forces peanuts out of its lower end and onto the web, in which the pockets have been formed. Suitable retaining Walls may be provided to direct the ow of peanuts.

As I prefer to have the second web l or printed sheet material, sealed to web l in an undistorted condition, I have provided a wheel to brush over the top of the lled pockets, ensuring that no vpeanuts will protrude above the surface of the pockets.

I seal the substantially wrapped articles in these pockets by applying over the top of the pockets a second web T, of printed sheet material. This web can be of any material which can be heat-sealed, glued, or otherwise secured to the edges of the filled pockets to complete the package, although in Figure l I have indicated the use of Pliolm, which I prefer to use in packaging peanuts because'.` of its' preservative effect and.` excellent heat-sealing characteristic.

Registration ofl printed matter This second web 'I of printed sheet material, is fed orV unwound from roll 8 around' idler rolls Which guide it into contact with the portion' of web I protruding or extending over the' rims' or lips of cups 6. Although this is n'otv necessary, IA prefer so to feed web 'l' onto drum 5v that the printed matter will not overlap from one cupto another and that it be uniformly registered with successive cups. In Figure'l, I have illustrated dia'grammaticallyv an apparatus for accomplishing this which I prefer toA use4 when web 'l can be made to shrink or stretch.

As'web' 'l is fed oryunwoundr from roll 8 itpasses in close proximity to roll 9; bearingon'itssurface at'v intervals the length of the distance between the printed matter onweb' 1k 'nsv l', heated in anyv conventional manner. Roll 9 and drum 5 are drivenV in. timed relation by sprocketV chains (not shown). As web 'i passes over closeto' revolving roll 9, the heated fins lcontactthe web between the printed'matter thereon', heating' pre'- determinedV narrow transverse zones ofY the web. It is a characteristic of Pliolm that it shrinks slightly on beingl heated and' also that it can then bestretched; Thus', by'using ak conventional electric eye or manuallycontrolledl device to'governl a variable speed drive, rolls H may beY made to increasev or' decreasev in speed'. If' thev printed panels arerrunning ahead of their intendedregistered position, then the variable speed drive: will retard the rolls I- a'nd-v hence retardy the-feed of the-web at this point, the differential speed producing a stretching eifectonl the web: Onlythe portions which are heated will stretch however, and-roll S-fis synchronized sothat only unprinted portions are'heat'ed", thus avoiding distortion of the printing. If the printed panels are running behind, the rolls Ilr will be made to` run slightly faster andv the heated portions of theV web-Will shrink so that rio-slack will appear. If aweb is used which doesnot' shrink sufficiently for this purpose, the panels willY be printed slightly closer together sorthat-there' will always-1 be a stretch A.of the filled pockets when both webs are of `Plio- Iiilm, even then I prefer to provide a roller I3 of "any suitable material, such as sponge rubber,M

driven in timed relation with drum 5 by sprocket chain (not shown), to further pressthe webs together-'licensure a good seal. If webs I and 1 are of such material that they will not seal on the mere application of pressure, conventional heat Sealers or gluers may be provided. A

As the particular peanut package I make is hung on a display rack by a hook, it is necessary to punch a hole in the end of each package, as seen in Figure 3. To accomplish this, I have provided a revolving punch, driven in timed relation with drum 5 by sprocket chain, not shown (omitted from the drawings by reason of the present scarcity of sprocket chain) Removal electrical insulating material, mount electrical.

resistance wire I4 which, either by itself or in cooperation with similar wires mounted on adjoining cups, substantially surrounds the rim of the cupi, as is best shown in Figure 2. After the pockets have been firmly sealed and holes punched in the end portions of the packages, if that is desired, these wires I4 are energized in any conventional manner (not shown). The heated wires sever the sheet material, the lled packages being held in cups 6 by a conveyor belt held against drum 5 by idler roll I5 and the continued application of the vacuum. The belt is formed of or covered with a heat-resistant material,v such as spun glass fabric, and its tension aids the hot wires in severing the packages. At the bottom of drum 5 the vacuum is released and the individual packages fall of their own weight onto the conveyor belt, which carries them away. Although I have not found it necessary, air pressure or mechanical devices may be employed to strip the filled packages from the cups if desired.

The illustrated form of the apparatus has some advantages even if neither web is printed as, for example, in packaging loose or liquid materials Where bringing together two partially-filled pockets would present diiculties.

If desired, one or both of the webs may be prestretched as, for example, in the manner shown in my co-pending application, Serial No. 436,666,

led March 29, 1942. It will be observed that the stretch-wrapping of the present invention is advantageous even if the wrapper does not ultimately shrink to cling closely around the article.

g-The'term article is usedfforI convenience and 'is intended to include a loose or liquid iill such as are contemplated for use with this invention.

The variable speed drive for controlling .the registration should be one capable of minute or infinitesimal variation, as for example, a Reeves drive, or it may be one which causes a momentary correction without changing the running speeds.

The pockets in the cups 6 may have their upper edges and bottoms iiat or concentric with the axis of the drum. If iiat, the pressure rollers should have enough resiliency to both accommodate the high spots and have adequate pressure on the low spots.

Although my invention is described herein as .relating to the use of Pliolm, it should be understood that this is illustrative only and the prinvciples of my method can be applied to any sheet material which is or can be made plastic or stretchable. It is to be further understood that, although I have described my invention in detail and therefore utilized certain specific terms and language herein, the present disclosures are illustrative, rather than restrictive. and that changes and modifications may be resorted to without de' parting from the spirit or scope of the claims appended hereto.

The web I may be held at the edges` in any suitable manner while passing around drum 5, if found necessary.

I claim:

1. An apparatus for packaging articles including means for advancing a sheet of plastic material, means for exerting pressure on successive portions of said sheet in a direction substantially perpendicular to the surface thereof to form a series of container-forming cavities in the sheet, means for depositing articles in the said cavities. means for advancing a second sheet of printed thermoplastic material, means for bringing predetermined parts of said second sheet into registration with the edges of the cavities in said first sheet by variably changing the length thereof throughout the entire width thereof, means efl'ective while maintaining the second sheet unpocketed for causing the portions of the said sheets surrounding the cavities to adhere to one v another to `seal the articles within the cavities, and means for severing the enclosed articles from the remaining portions of said sheets.

2. The method of registering predetermined indicia-bearing portions of a rolled up sheet of plastic material having spaced indicia thereon with an advancing series of articles comprising advancing the sheet from the roll, changing the length of the said sheet throughout the width of the sheet as it 'is being advanced toward said articles selectively to` bring said indicia-bearing portions into registration with each of said articles, and applying said sheet to said articles in sequence.

3. A method of packaging, including the steps of softening an unprinted plastic sheet, running it around a drum, distorting portions of the sheet in a, direction generally perpendicular to its faces to form pockets therein, iilling the pockets with a ll lying substantially entirely within the pockets, registering with the pockets predetermined portions of a rolled up sheet of printed plastic material by advancing the sheet from the roll, changing the length of the said sheet throughout the width of the sheet, as itis being advanced toward said pockets, selectively to bring printed portions into registration with said pockets, and

. 5 with an advancing serles of articles comprising advancing the sheet from the roll, changing the length selectively of unprinted portions of the said sheet throughout the width of the sheet as it is being advanced toward said articles as may be necessary to bring said printed portions into registration with each of said articles, and applying said sheet to said articles in sequence.

5. A method of packaging, including the steps oi softening an unprinted plastic sheet, running it around a drum, distorting portions of the sheet in a direct-ion generally perpendicular to its faces to form pockets therein, filling the pockets with a fill lying substantially entirely Within theI peck,- ets, advancing a sheet of printed plastic material, controlling the advance of the printed sheet to register printed portions with said pockets, and applying said printed sheet to said pockets in se.- quence, while maintaining said printed sheet unpocketed, to close the pockets, and severing the closed pockets from the sheets'.

WILLIAM S. CLOUD.

8 REFERENCES GI'BED The following references are of recordv in the die of this patent:

UNITED STATES

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