US2056094A - Method of making paper boxes - Google Patents

Description

Sept. 29, 1 936.

c. 1.. CLAFF METHOD OF MAKING PAPER BOXES Filed Nov. 27, 1955 2 Sheets-Sheet l Sept. 29, 1936. c CLAFF 2,056,094

METHOD OF MAKING PAPER BOXES Filed Nov. 2'7, 1935 2 Sheets-Sheet 2 Fntented Sept. 29, E33

titre sites getter an airmen I This invention relates to paper boxes and more especially to a method of making boxes from box board material.

Heretoiore in the construction of boxes it has been the practice to cut a blank, fold the sides and side wings, thereafter applying the end fold to the outer surfaces of the wings and axing it thereto with a light pressure, and subsequently bending the end fold into the box so as to straddle the end wings, at which time the fold is subjected to a heavy pressure to flatten it and complete the formation of the box.

While the operation described has been ef== fective the resultant box has been objectionable for certain reasons. For example, if it has been desired to reduce the thickness of the exposed side edges of the end fold a separate operation has been required. Furthermore the final heavy compression to which the end of the box has been subjected following the initial light pressure, has,

resulted in an extrusion or shift of the material of the end told at its bend which has caused said fold to protrude an objectionable distance where straddling the inturned side wings, thus produc ing an unsightly, uneven appearance on the box lid or box produced by the method.

An object of the present invention is to avoid the disadvantages stated by improving upon the method of producing the boxes whereby, through the application of a heavy initial pressure the end fold, while partly folded, is aflixed to the inturned wings, compressed at its side edges to reduce the thickness of said edges and allowed to extrude or elongate toward its free end prior to the final bending of the fold down over the wings so that this added area of the fold can be compensated for by bending the fold after the extrusion or extension has taken place instead of prior thereto, thus to reduce the objectionable bulging bend in the fold and render it less conspicuous.

Another object is to subject the completely folded box to a light pressure as a final step in the method, this pressure being sumcient merely to bring the several thicknesses of the box end together to insure proper adhesion.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts and in certain steps of the method hereinafter more fully described and pointed out in the claims, it being understood that changes may be made in the construction and arrangement of parts and in the disclosed method without departing from the spirit of the'invention as claimed.

In the accompanying drawings the preferred form of the invention has been shown.

In said drawings:

Figure l is a plan view of one end of a shaped blank prior to the folding operation.

Figure 2 is a similar view showing the sides and side wings bent to proper positions.

Figure 3 is a section on line 3t, Figure 2.

Figure 4 is a plan view showing the end fold raised against the wings.

Figure 5 is a horizontal section through the end of the box with a former and a pressing and shaping die applied thereto while the end fold is in the position shown in Figure 2.

Figure 6 is a section on line 5-6, Figure 5.

Figure 7 is a section on line 71-11, Figure 6.

Figure 8 is a plan view of the folded end of the completed box.

Figure 9 is an enlarged section on line 99, Figure 8.

Figure 10 is a side elevation of said end showing', by broken lines, the approximate position or the bend in the end fold if the present method is not followed.

Figure 11 is an elevation of one side portion of the end orfront of the completed box.

The present method includes, first, the formation of a blank 5 having sides 2 and side Wings 3. The blank can also be made with an integral end fold 6 although, if preferred, this end can be a separate piece such as shown, for example,

' in the patent to Clair No. 1,579,646 dated April Following the shaping of the box members, the sides 2 are bent perpendicularly to the bottom of the blank and the wings 3 extended toward each other as shown in Figure 2.

The end fold t is next applied to the wings 3 in an unfolded condition as in Figure 4 and at the same time a. former A within the box and a shaping and compressing die B are moved toward each other to subject the wings 3 and the engaged portions of the fold to very heavy pressure. The die B has rounded or beveled shoulders C adapted to press against the side edges of the end fold so that during this initial and heavy compression, said edges will be so compressed and shaped or embossed as to cause the finishing or covering paper 5 on the fold to partly or entirely cover the raw side edges of the die-engaged portion of the fold. This has been illustrated in Figures 5 and '7.

Usually at this stage of the known methods of making boxes, the end is subjected to a. pressure only sufficient to hold the end fold momentarily against the wings to insure adhesion. Thereafter the free portion of the end fold has been turned down into the box and the entire end then subjected to a very heavy pressure. This has resulted in forcing the bent or fold portion of the end fold upwardly away from its original position, as shown for example by broken lines at :z: in Figure 10. Thus an objectionable bulge has been produced showing raw edges and forming an open-ended'loop.

In the present invention, however, the initial heavy compression of the partly folded end between the former and the die not only shapes the side edges of the engaged portion of the end fold and afiixes said portion to the wings 3, but it also causes any upward displacement, such as extrusion or stretching, to occur before the final bend occurs, as shown by the arrow in Figure 6. Therefore when the final step occurs of turning or bending the end fold over the edges of wings 3 and down into the box, the bend or turn 6 of the fold will hug closely to the edges of the wings, as shown by full lines in Figures 9 and 10 so that the extent of the protrusion of the bend above said edges will be reduced to the minimum, which is the thickness of the material of the fold.

It is to be understood, of course, that the term box" herein used is to apply to either the body or the cover of a box, both of which can be made by the same method.

What is claimed is: I

1. A method of producing boxes which includes the steps of inturning the side wings of a blank, applying the outer portion of an end fold to the outer faces thereof under a pressure suflicient to emboss the opposed side edges of the engaged portion of the-end fold and tightly compress the lapping portions of the box, subsequently bending the end fold snugly over the edges of the wings and into the box, and finally subjecting the bent end fold to a light pressure sufficient to cause it to bear against the wings without displacing the bend of the fold.

2. A method of producing boxes which includes the steps of inturning the side wings of a blank, applying the outer portion of an end fold to the outer faces thereof, subjecting the lapping portions of the wings and fold to compression sufficiently heavy to emboss the opposed side edges of the fold, and allow extrusion or stretching of the material of the fold into its uncompressed portion, thereafter bending the uncompressed portion of the end fold snugly over the edges of the wings and into the box, and finally subjecting the inturned portion of the end fold to a pressure suflicient to bring it against the inner faces of the wings without displacing the bend of the fold relative to the edges of the wings.

CLARENCE LLOYD CLAFF.

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