US2037777A - Container made of paper and method of making such container - Google Patents

Description

April 21, 1936. M. E. GAZETTE A 777 CONTAINER MADE OF PAPER AND METHOD OF MAKING SUCH CONTAINER Filed Feb. 4, 1935 2 Sheets-Sheet l April 21, 1936. M. E. GAZETTE 2,037,777

CONTAINER MADE OF PAPER AND METHOD OF MAKING SUCH CONTAINER Filed Feb. 4, 1935 2 Sheets-Sheet 2 I 1 1 vewi'or Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE.

CONTAINER MADE OF PAPER AND METHOD OF MAKING SUCH CONTAINER Application February 4, 1935, Serial No. 4,831

' 6 Claims. (Cl. 229-45) This invention relates to improvements in containers made of paper and methods 'of making such containers.

More especially it relates topaper cans, cups and the like, made of heavy paper or paper board in a tapered shape, capable of standing nested together while held in supply stock ready for service in holding liquids, semi-liquids, powders,

10 etc.

lindric'al or conical, those of each type having certain advantages and certain disadvantages.

Those of cylindrical type can be cut from continuous cylindrical lengths of plural-ply helicallywound paper tubing. In addition to thus having wall structure of superior stiffness and strength, cans of this type can receive tightly crimped bottoms, and can be tightly closed at the top by cylilndrically fitted caps; and they are of low cost to produce. Conical containers obviously cannot be cut fromeontinuously conical tubes. One of the best varieties of these is made from flat cardboard stock, by'cutting a sector of a. flat ring of paper, and then wrapping that sector into a frustum of a cone, with the radial, side edges of the sector overlapping each other; and then, for making a plural-ply structure, repeating that operation by wrapping a second sector of paper on top of the first. This is a less continuous operation of manufacture. poses the grain of the paper has to run longitudinally of the cone; and therefore the paper stock 4 does not afford the maximum resistance to collapsing of the can walls of which that paper stock would be capable if the fibres ran in circumferentlal direction. Each lapping of cardboard makes a double thickness of stock, and to this a thickness of glue is added. This makes difficulty when it is attempted to crimp in a bottom closure disk, because the ridges of the conical wall where the paper is of double thickness are themselves more than doubled by the crimping, which may interferewith the proper and required tightness of the enclosure. And the top closure, if any, is usually merely a plane disk snapped into a groove, at a distance below the top.

The superiority of the plural-ply helicallywound tubular body of the cylindrical can has long beenrecognized, especially for uses in which liquid is to be held for any considerable period, or is to be carried in the hand, and also because its type of top closure has the convenience that the container can be used as an accurate measure of contents, for making retail sales, by filling it flush full, since its cylindrically flanged cover is received on the outside of the cylindrical top portion of the can.

On the other hand, the conical containers have the important advantage that they may be nested together when empty, with a conservation of Stifi' paper containers are ordinarily either cy- For practical purspace which can be translated into substantial savings of money costs of freight and storage.

It is a primary'object of the present invention to provide a still? smooth container made of paper in such a way as to combine in itself the characteristic advantages of these two types, and to be exempt from the characteristic disadvantages of each, assuming equality in materials, weight and number of plies.

The invention provides for utilizing ordinary plural-ply helically-wound long tubular paper stock; converting successive, suitable sectional lengths of such from cylindricality of conicality through nearly allof. the extent of the section, but leaving at the top of the can a cylindrical lip portion in its original cylindrical form and strength, to constitute a seat for a flanged cylindrical closure cap; and preferably having also a cylindrical portion at the smaller end of the taper, for most conveniently and without operative difllculty crimping the bottom to a tight jointwith a transverse closure disk.

It is an important feature that all exterior surfaces of this improved can body are approximately smooth and free from jog. The straight lines superficially visible. in the finished product result from the method of manufacture,.b11t are merely visual in effect and do not indicate appreciable unevenness of surface. They mark positions where the wall asa whole has variations of density.

The first step of the converting operation is accomplished by the outsetting or insetting of longitudinal hollow ridges tapering in depth from the initial cylindrical shape of the body walls;

and simultaneously the circumference which has furnished thestock for the making of the side walls of .these ridges comes down to a smaller diameter of circumference. The number and character of such ridges will determine degree of taper of the can. Preferably the ridges may be of relatively small breadth, distributed sparsely around the can, the conicality of the ultimate product is determined by therate at which they increase in depth from zero at the cylindrical lip to the maximum depth of these ridges at the bottom end of the body. The making of these ridges shifts a certain amount of paper stock, which initially was lying circumferentially in the cylinder, into approximately radial setting; and.

of these hollow ridges is by a later step to be returned, with increase of density, into the circle indicated by the residuary parts of the circumference (intervening between ridges) at their new location. In this later step the gap between each two residuary portions of the circumference becomes filled with the stock which was in the walls of the ridge, radial and circumferential.

This step involves the discovery that the paper stock of said hollow ridge, together with such portions of the stock of the residuary fragments of circumference as were adjacent to that ridge, are all together capable of being molded and compressed to the standard thickness of the can wall.

The stock of the radial portions which were subtracted from the circumference in order to reduce the diameter is thus reincorporated in the circurnference; but it no longer contributes to length of circumference. Its condensation constitutes instead a sort of rib within the thickness of the wall.

The smooth tubular wall thus made can be crimped with the flange of a bottom closure disk in a well-known and usual manner, so as to produce an effective liquid-tight seal; and thus the problem is solved of how to close tightly the end of a paper tube whose diameter has been reduced by a forming of ridges therein. Preferably the end portion of the tube which is to be used for the crimping is made cylindrical, by the taper not being carried quite to the end, as a cylindricality of both walls which are to be crimped together facilitates the crimping operation.

In the walls themselves the fibres of the paper stock then extend around the tube with sufficient directness to afford desired stiffness of body for resisting collapse when held in hand with liquid contents, because the fibers predominantly extend lengthwise of the original paper strips by the helical winding of which the tubing was made. The longitudinal dry-molded regions of condensation wherein these helically extending fibres are concentrated, tend to enhance the rigidity and strength of the can body, and may in some cases permit the use of lighter stock for getting a desired result. The top lip of the can retains iits pristine cylindricality, and therefore can be tightly closed by a cylindrical cap.

It is intended that the patent shall cover by suitable expression in the appended claims, what- .ever features of patentable novelty exist in the invention disclosed.

Inthe accompanying drawings:

Figure l is a perspective of a section of pluralply, helically-wound paper tubing, of well known style;

Figure 2 shows elevations of a male and female die, the latter die being in medial section, by which a certain length of the tubing of Figure 1 may be subjected to the first step toward converting a portion of the tube to conical'form, by a shifting of parts of the original circumference into radial settings, thus making longitudinal ridges;

Figure 3 is a perspective of the tube as reshaped by the dies of Figure 2;

Figure 4 is an elevation looking along the axis of the dies of Figure 2, and showing those dies as if moved toge her with the tube engaged between them, in on approximately at 44 of Figure 2;

Figure 5 has, ations as in Figure 2, of a male die and a female die suitable for re-setting into circular form the out-set stock of the ridges in the tube of Figure 3, and for dry-molding the the ridges of such a tube in process of paper stock in these regions, showing also a position for a tube like that of Figure 3, preparatory to undergoing this step;

Figure 6 is an elevation of a fragment, in section transverse to the axis, showing the stock in being reset by the dies of Figure 5;

Figure 'l is a perspective of a. tube after undergoing the action of the dies of Figure 5;

Figure 8 is a perspective of a fragment of the tube wall of Figure 7 showing, in section transverse to the axis, and on an enlarged scale, to what final positions the paper stock at each ridge becomes compressed and dry molded;

Figure 9 is an elevation of a completed can, with fianged cap-closure applied, and having a bottom portion broken away to show in section the crimped joint of a bottom permanent closure, and

Figure 10 is an elevation in section comparable to Figure 4, of an embodiment in which the ridges are set inward from the tubular wall.

Referring to the drawings, the tube of Figure 1 represents a section of ordinary plural-ply heli-- cally-wound paper tubing such as is commonly used in the manufacture of cylindrical paper cans. This tubing may have two or more plies of thickness, and can be made economically by continuous process, in endless lengths in sizes suitable for manufacture of paper containers. As ordinarily constructed the component strips of paper are out lengthwise of the grain of the paper; and then, if there are two plies a and b as represented in Figure l, the grain of each, and the preponderance of fibre lengths and of strength of the paper of each, runs helically around the cylinder, so that force tending to collapse the tube meets a stronger resistance of fibres than if the fibres ran parallel to the axis.

According to the invention, a section of this tubing, of suitable diameter and length, is to have the greater part of its walls converted from its initial cylindrical shape to a conical shape in which, preferably, there are no projections or extra thick areas on the walls. The invention accomplishes this by means of two sets of dies, each set being a pair comprising male and female, of which the individuals are movabe axially together, the. dies being preferably non-rotary.

The first pair of dies is shown in Figure 2, wherein the male die 10 has a short cylindrical portion l2 for fitting the interior of the paper tube, and thereby holding that tube. Said tube is shown by dot and dash lines at l4. The greater part of this die is a tapering portion l6 which is of a generally conical form but is provided with a series of ridges l8 extending axially. These grow progressively more prominent from a zero height at the edge of the cylindrical portion [2 to a point of maximum height of ridge at the smaller end of the cone l6. As represented the cone has eight of the ridges I8, equally spaced around it, but the number and shape or other character of the ridges may be varied as desired for most agreeably getting the pitch which the ultimate conical frustum of paper walls is predeterminedto have.

The female die 20 of Figure 2 has a conical chamber 22 of shape to receive the cone l6 of die in, with longitudinal grooves corresponding to whatever ridges l8 are on cone IS. The cone 22 and grooves 24 are of suitable oversize as regards the ridges l8 to allow space for the thickness of paper walls of the tube to intervene when these two dies are together. The grooves 24 may be like the ridges it in that the radial depth of each relative to the conical adjacent surface of the chamber mayv progressively'increase toward the inner end of the chamber of the die. No cylindrical portion, at its mouth, is needed for cooperation with the cylindrical part 12 of die lb. The grooves 24 may be complete slots, as

represented. The radial heights of the ridges on I the die, and also on the tube walls, are exag gerated for clearness'oi showing.

As the dies i0, 20, are brought together, with a-section of cylindrical paper tube 23 on the mandrel H), the walls of chamber 22 engage around the tube walls 23 and graduallyp'ress them inward toward the axis.

ferential constriction is experienced by the paper 23, but relief is found by bulging into each groove 24. As the axial movement of the dies nears its end the ridges l8- gradually extend those grooves and give shape to the paper stock in them while the closing of the main conical male and female surfaces intervening between grooves ejects into those grooves whatever paper stock if any, may have bulged toward the axis between the grooves. This produces the shape seen in Figure 3, in strict confinement between the dies, as seen in Figure 4 in which the initial cylindrical shape has. been reduced toridged conical shape, with straight line wrinkles of the paper, having crests 26, forced by the ridges I8 into the grooves 24. The portions of paper 21, which initially werecylindrical between the positions of these' ridge wrinkles 26, retain'circularity of shape, but are formed on smaller radii of curvature, which radii diminish progressively,

as represented in Figure 3, toward that whichis to be the bottom endof the can, thus constituting the paper with a shape which is of a.

generally conical style but has outstanding hollow wrinkles of paper, preferably with sharp square corners as represented. Meantime the-part 21 of the tube which was on the cylindrical part Id of the male die has retained its cylindrical form.

and original size. Figure 4 shows a cross-section of the tube of paper while between the dies Ill, 20, at the end of their compressive and reshaping action.

Considered as a whole, the tube wallhas thus been made into a modified conical curve, in which there are two circular sets of conical fragments of wall, 21 and 26; and also there are radial fragments 25, which join them, these being the radial side walls of the hollow ridges.

The stock thus taken out of the original single cylindrical curveis now to be setback into the main conical curvature indicated by the frag ments 21. This is accomplished by the second pair of dies, shown in Figure 5, wherein the male die 28 has a conical portion shaped to fit the interior of the curves 21 of the re-shaped tube of Figure 3; and the female die 30 has a chamber whose walls correspond to the exterior of those curves. Therefore when a tube, as that of Figure 3, is placed on the die 28, and the two dies 28, 30, are broughttogether with sufficient pressure, the hollow ridges 26 first are collapsed, as shown at an intermediate stage in Figure 6; and then by continued advance and pressure of the dies, the

material of the flattened and collapsed ridges 26 becomesdry molded into the gaps which were between the main sections2'l, and becomes condensed with theadjacent paper stock, until at the conclusion of stroke of these dies, the thickness of wall at every location around the tube approximates uniformity. This collapsing and dry A severe circummolding of the stock involves a swedging whereby the hollow originally made on the inside of each ridge 26 gradually becomes filled with paper stock expressed from surrounding regions. In the ultimate result there is no vestigeoi' this hol-- low remaining, except that two parallel cracks visible on inside and outside, extend: from the small end of the cone to the cylindrical lip portion 2|, which remains unchanged, and around which the flange of an ordinary cap cover 34 can tightly engage. Thedry molded and condensed portions of tube walls provide ribbed regions extending longitudinally, and eachregion has a single-ply mid-rib flanked along each side by a three-ply rib. During this compressing of the paper stock,

'each radial wall 25 of a hollow ridge 26 becomes laid upon the adjacent stock, making a dovetail shape in cross-section, and sinks into it, and also flows or is molded somewhat toward the middle of the channel. This is evidenced by the ultimate uniformity of thickness in the whole region where each channel has been, and by the minute medial crack 36 extending along the outside, showing that there has been flowage inward from each side of the channel toward its middle, and at the same time-toward the axis. As the grain of the original paper was not parallel to the, channels, this flowing of stock-transversely of them makes no split. Also, the flowage of stock involved in the original thrusting out of the ridge involved ,no weakening, for the same reason. And if the bounded merely lend character to the exterior surface by appearing. as decorative lines which accentuate the'general attractiveness of the finished container.

By thus 'attaimng approximate uniformity of thickness of paper stock, the crimping-in of a bottom closure according to the well known :methods beeornes' feasible and eifective to make a tight joint commercially practicable. The areas of highly condensed stock respond to the crimping die as incylindrical'cans.

The crimping in of the bottomfianged closure can be effected more conveniently if both of the crimped surfaces are cylindrical. Therefore it is preferred to make three-fourths of an inch or so of the end portion 'ofthe male die 28 cylindrical,

as represented in the drawings; and the female die to correspond. The conical end portion of a tube like Figure 3 easily assumes this cylindrical shape when thrust upon such a die as illustrated in Figure 5, without it being necessary to have a corresponding cylindrical section at the smaller end oldie l0.

The-description of one embodiment of the invention which has thus been made is to be considered as being illustrative rather than as.being limiting, as the invention can :be "embodied in other ways. ple, may'with like effect beset inward toward the axis, instead of outward fromit as here illustrated, in order to extract circumferential The wrinkles 25, 26, 25, for exam material, and to set it radially, 'and then later to return it to the circular formation of the desired cone. Figure 10 illustrates this arrangement. Both kinds of ridges maybe arranged ,alternately -in thesame set-of dies, if desired.

complishes the condensation to smoothness is preferably rectilinear and non-rotary, because the mechanismfor this is of utmostsimplicity; but it will be obvious that asthe ridge of paper as, 20,. 25 is being spread "and condensed to the form of Figure 8 a slight rotary oscillation of one die while the other is stationary would do no harm and i might help in wiping the folds to their desired seats on the stock at right and left.

If it is not desired to provide atthetop for the: flt of a cylindrical cap,-the taper of the ultimate product may extend tothe largeend of the container; but it will be observed that the cylindrical lip portion illustrated has also utility for holding the initial section of tubing and for providing a. pleasingdlnish forthe cup or can; and that it can be further molded, ii'desired. to adapt it to receive some other type of top closure.

Also as the invention provides a tapering tube with cylindrical portions at either or ends,

it is obvious that either end may be the one at which the permanent closure is crimped, to con+ stitute the bottom; v

For convenience in the specification and claims the words cone and conical? are herein used in the broad sense of signifying any style of taper since, in practice, the taper of the container body a is not necessarily me such as would be generated by revolutiono'fronly a straight line element;

1 claim: i I i a 1. Themethodof producing a tapering container niade of paper, comprising the displacing of portions! the wall a' cylindrical tube of paper, into longitudinal hollow ridgu atintervals around the cylinder, each ridge having depth progressively increamng, whereby the structure becomes conical by diminution of extent of stock between the ridges; tollowed byfa radial pressing ctstockofeachsaidridgeintothespac'eatthe entrance to its hollow while the adjacent cone walls areunyieldingly' the side toward which said radial meme is acting; said radial suillciently severe, at the end of the taper where the ridg'e-deptliis the greater, to eiiect there a condensing of the stock at each ridge to approximatelythe thickness of the paper stock at portions of the cone walls which intervene between ridges.

2. The method of converting a smooth cylindrical tube of paper so that it has a smooth portion of reduced diameter, comprising the bending of the paper wall of the tube into a circumferential series of longitudinal hollow ridges, each having progressively increasing radial measure -of displacement with respect to the portions of the tube wall which adjoin it,'intervening between adjacent ridges, thereby forming said intervening portions into tapering form; and r then applying radial compression to a portion of the tube ridges and thereby forcing paper stock, being laid against said mid-rib and stock of each ridge back into thespace which it was bent, condensing the stock of those ridges and of the region of wall immediately adiacent to each into form which is approxi-. mately uniform in thickness with the thickness 5 of said intervening portions of 3. A container having a tapering tubular paper body comprising the paper stock of a cylinder of paper, the circumferential excess of which stock over that requisite for composing the tapering form being distributed and condensed in lengthwise-rib regions, the stock at an end portion of each said region which is toward'the smaller end of the said-taper having a mid-rib; which is. a condensate of the paper stock,single-p1y and of full thickness of the body walls, and having folded at each side a three-ply rib whichis a condensate oi the paper'stock, being laid against said midrib and condepsed to a thickness, approximating the thickness saidmid-rib and of adjacent .single jply non-rib portions of the walls of said 4. A container having a tapering tubular-paper body. comprising the paper stock of a cylinder of paper, the circumferential excess of which stock over that requisite for, composing the tapering iorm being distributed and condensed in lengthwise-rib regions, the stock at an end portion of each said region which is toward the smaller end of the said taper having a single-ply mid-rib,

condensed of the paper stock, intimately flanked along each side by a three-ply rib condensed of .the paper I of the cylinder-excess of stock displaced laterally stock; each said mid-rib having some thickness of adjacent portions of the body walls 40 j intervening between the rib regions.

:Qr A container having a tapering tubular paper bodycdmprising the paper stock of a plural-ply helically wound cylinder of paper, the circumferential excess of which stock over that requisite for composing the tapering form being distributed and condensed in lengthwise rib regions, the stock at an end portion of each said region which is toward the smaller endof the said taper having a mid-rib which is a condensate of the paper stock, free from told and approximately of the thickness of the body walls, and having at each sidea folded-"rib which is a condensate of the condensed to a thickness approximating the thickness of said mid-rib and of adjacent nonrib portions of the walls of said body.

6. A container having a tapering tubular paper body comprising the paper stock of acylinder of paper, the circumferential excess of which stock over that requisite for composing the tapering form being distributed and condensed in lengthwise-rib regions,'the stock at an end portion of each region which is toward the smaller end of the said taper being a condensate of folds of the paper stock which in cross-section as condensed are organized in dovetail shape; and, at an annular end portion of said tapering body, said condensates being condensed to a thickness approximating'the thickness of adjacent portions 79 of body walls which intervene between the said. lengthwise-rib regions.

, MARSHALL E. GAZETTE.

CERTIFICATE OF CORRECTION.

Patent No. 2,037, 777. April 21 1956.

MARSHALL E. GAZETTE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1 second column, line 15, for the word "of" read to; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 19th day of May, A. D. 1956.

Leslie Frazer (Seal) Acting Commissioner ofPatents.

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