US2568664A - Method of producing paper drum containers - Google Patents

Description

Sept. 18, 1951 A. L. SCOTT METHOD OF PRODUCING PAPER DRUM CONTAINERS Filed Oct. 16, 1947 2 Sheets-Sheet 1 Arthur L. Scott Sept. 18, 1951 L SCOTT METHOD OF PRODUCING PAPER DRUM CONTAINERS Filed Oct. 16, 1947 2 Sheets-Sheet 2 Y7 ig u,

i 8 gvwmvtm Ar Thur L. Scofi odsof making the same.

cerned with a container, the walls of'which com- Patented Sept. 18, 1951 OFFICE METHOD OF PRODUCING PAPER DRUM CONTAINERS Arthur L. Scott, Columbus, Ohio Application October 16, 1947, Serial No. 780,173

2 Claims.

This invention relates to containers andmeth- In particular, it is con weight and ability to withstand abuse in handling and shipping. The latter advantage, how- 1 ever, has heretofore been greatly lessened in the case of cylindrical containers becauseof the diificulty in producing a truly strong bond between the container wall and the end closures. The joint btween the wall and an end piece is in- Itrinsically a point of weakness because it occurs at both a discontinuity in the contour and a discontinuity in material. abrupt corner must usually be retained because While the more or less of the practical necessity for flat ends upon which the container may stand or with which it may I abut its neighbors in the saving of storage space,

the ideal construction would be one in which the material of the wall passed continuously into that of the end. Not only would maximum 'strength he thus obtained but also economy in the avoidance of fastening devices such as crimping bands.

"The primary object of the present invention,

therefore, is to provide a cylindrical container having integral side and end walls.

Another object is to provide a method of mak- "ing sucha container without waste of material,

the blanks for two containers or for a container and its removable cap being complementary in outline and thus derivable from a single strip.

Still another object is to provide a construction for such a container which will render it highly impervious by reason of multiple overlapping of its elements.

These objects I accomplish by means of a blank having a serrated edge. The serrations take the form of elongated triangular tabs with triangular notches therebetween, the length of the triangular tabs equalling the radius of the finished container. The blank is wound upon a mandrel of the desired size with the tabs projecting beyond it. The tabs are then bent inwardly against Y the mandrel end, preferably in a progressive 7 fashion as they reach the mandrel in the winding process.

The width of the tab bases is so chosen that a large number of them, say twenty to twenty-five,

occur on the container circumference, whereby the distortion in bending over the arcuate edge joining wall.

is minimized. The tabs reach to the center and lie in an edge-to-edge fashion as segments of the circle. When a complete turn has been made upon the mandrel, the end is completely covered by the tabs, the last tab being more than sufiicient and thus overlapping the first. Due to this initial overlap, each tab of the new layer overlies a junction in the preceding layer and as the wind-'- ing progresses a completely impervious structure results.

Both the zone of weakness where the sharp points of the tabs meet at the center and the tendency of the tabs to retreat from the center due to the increase in radius as the winding progresses are attended to in a simple and effective manner. A plurality of discs, of the same material as the blank, are interposed between the various layers of tabs. Where a flat outer surface is desired, a recess is formed in the mandrel end to accommodate the increased number of thicknesses. The length of tab is so chosen that the points of the outer layer meet at thecenter. The points of the inner layers would overlap the center by progressively greater amounts, due to the decreasing radius of the turns on the mandrel, if it were not for the fact that they need to bend progressively deeper into the recess as the number of discs increases. This number may be so chosen that the compensation is practically exact.

It will be understood that some form of bonding occurs between the layers. The stockmay be impregnated with a thermoplastic or thermosetting material and appropriately treated during the formation or after completion of the container, or a simple adhesive may be applied as the stock approaches the mandrel.

Wastage of stock is eliminated since the serrating produces two blanks, each having triangular tabs and notches, which are bothusable.

In the drawings,

""Fig. 1 is a diagrammatic perspective view illus- 'tratin'g' a method of making a container and a closure therefor;

- Fig. 2 is a bottom plan of a container;

Fig. 3 is a sectional view taken on the plane of Fig. 2;

Fig. 4 is a plan of a serrated strip showing the two blanks derivable therefrom;

Fig. 5 is a perspective view of a closure or container cap made according to this invention;

Fig. 6 is a similar view of a container;

Fig. 7 is a longitudinal, medial section of a container illustrating the contour but omitting the fine structure of the wall and end; and

Fig. 8 is an enlarged radial section showing the structure of part of the container end and ad- In the drawings, a preferred form of my contion of thetedges.

. terlocked pattern -of Fig. '3.

h completion of each convolution. "on the outer surface to prevent the lifting of the outer set of tips.

' among the various convolutions. vided, in the mandrel end, of sufilcient depth to accommodate the added thickness of the discs.

tainer is illustrated, along with an indication of From the dies the blanks are led to mandrels" or forms and 2|. In the set-up shown in Fig. 1 a container and its caparebeing simultaneously produced. Accordingly, the form 2| is sufilciently larger in diameter than the form 20 to produce the desired fit of the finished parts.

The winding of the strips is done atthe end of the mandrels whereby the serrations l! are allowed to overhang. The latter are then bent atthe edgeof the form, all at one time at the --completion of the winding or, preferably, progressively as the reach the mandrel.

The triangular portions are so proportioned that they fit together in edge-to-edge relationship as segments of the circular end. Theoretically, of course, itis not possible to form the arcuate bases of the segments, using a fiat material, but in, practice, where a sumciently large number of segments are used, the bulging at the corners is hardly perceptible and is flattened downbysucceedinglayers. Similarly, the theoretical impossibility of having identical triangles produce segments of increasingly larger circles as the winding progresses is resolved in practice by 'a barely perceptible overlap or aminute separa Here, again,.succeeding layers cover all discrepancies. H

The segments pertaining to a given convolutionof the wall strip overlie the juxtaposed edges of those pertaining tothe preceding convolution. This salutoryeffect i-s-obtained by having the in- "terval or spacing between successive serrations a non-aliquotpa-rt of the cylinder circumference. 'This is illustrated inFig. 2where it is evident that all .segments after'the twenty-third will close the joints below them, resulting in .the in- It willbe evident thatthe joints in every second layer are'prevented from coinciding by the increasing circum-f erence.

To close any opening which may be left at the center and to reinforce the slender tips of the segments, it is' preferable to apply discs 25,

- usuall'y'of the same material, which are of sufficient size to cover the zone'of weakness. Any appropriate number of discs may be included, depending upon the material usedand the service to "which the container is to be put. In the average type of container it is preferable 'to start with a disc, which will 'thusrbe on the inner-surface to pr'event the liftingof the inner set of tips, and then to add an additional one at the This tplacesione As shown in Fig. l, the discs'may be secured, by an appropriate applicator not shown, to the tips of individual serrations before they reach the mandrel. As these serration are subsequently -bent into positionthe discs assume their pro-per place at the center.

Figs. '7 and 8 illustrate the action of the discs in compensating for the change in radius A recess is'pro- I flat outer surface.

'4 I as illustrated at 26. The inner disc 25 enters the recess and the first set of segments l1 bend axially inwardly to lie thereon. As the number of discs increases, succeeding sets of segments are bent to lesser degrees. Because the segments are drawn radially outwardly to an increasing extent by theenlarging bend at 21, their inner 'tipscan be made to remain' practically at the center 28. The outer disc 25" then completes the assembly and forms a continuation of the -A's previously'mentioned, any appropriate form of 'bondingmay be used to bind the layers. Thestrip'may, for example be passed through and impregnating bath, not shown, or may have an adhesive'coated'thereon, as by applicators indicated at 30 in Fig. 1.

A container made according to my invention is illustrated in Fig. 6, and a cap therefor in Fig. 5.

The method is'particularly well adapted to the production of the larger sizes of *containerasay 10 gallons to 50 gallons, and results in a very durable article. As an example may be mentioned-a test specimen, made of laminations of kraft paper, which was filled with 70 pounds of sand and then shipped by express and motor freight onseven round trips totalling 2,850 miles. Be

spite the severe abuse which this entailed, the

container. remained structurally sound.

'While 'Ihave shown and described asingle embodiment of my container it will be evident that the method may be extended to the .produc-' tion of various forms and modifications of that shown.

I claim:

1. A method of making a container comprising, serrating a strip of material, securing reinforcing-.discsto some ofthe serrations, winding the unserrated portion on a cylindrical .form, bending the serrations radially inwardly to produce a closedend and to cause the. discs to overlie portions of preceding serrations, and. causing continguous layers of material to adhere.

2.. A'method of making acylindrical container and .closure therefor comprising, longitudinally serrating astrip of material to produce a first strip having triangular extensions approximately equal in length to the container radiusand-an unserrated width equal to the container length and, a second strip having similiar extensions and. an unserrated width equal to the closure length, winding the strips on cylindrical forms having container and closure diameters respectively, bending the extensions radially inwardly to produce closed ends, and causing continguous layers of material to adhere.

' ARTHUR L. SCO'I'I.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 192,727 Switzerland Nov. 16, 1937

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