US3414184A - Flush corrugated fiberboard box joint - Google Patents

Description

Dec. 3, 1968 R. w. LOHEED 3,414,184

FLUSH CORRUGATED FIBERBOARD BOX JOINT Filed June 1, 1967 INVENTOR. R ICHAR D W. LOHEE D.

ATTORNE? United States Patent 3,414,184 FLUSH CORRUGATED FIBERBOARD BOX JOINT Richard W. Loheed, West Lafayette, Ind., assignor to Inland Container Corporation, Indianapolis, Ind., a corporation of Indiana Filed June 1, 1967, Ser. No. 642,741 7 Claims. (Cl. 22948) ABSTRACT OF THE DISCLOSURE Manufacturers joint for a box formed from a blank of corrugated fiberboard having two liners and corrugating medium therebetween, the joint being formed between the two adjacent edges of a blank having an inner and an outer liner and intervening corrugating medium, one edge of the blank having the liners extended to form lap portions beyond the edge of the intervening corrugating medium, with the inner lap portion of the inner liner being offset outwardly and adhesively bonded to the outer liner to form a lap of the thickness of both liners and of substantial width, and the other edge of the blank having its outer liner pressed inwardly along the edge for a width at least as great as the width of the lap, to provide an olfset area, and an offset at least as great as the thickness of the lap, and the lap being adhesively secured to the offset area in overlapping relation thereto.

This invention relates to corrugated fiberboard boxes, and more particularly to the manufacturers joint.

Corrugated fiberboard boxes, as manufactured by the box maker, generally constitute a scored and slotted blank, with the joint between the blank ends completed so that each blank comprises a double thickness of corrugated fiberboard, each thickness including closure flaps usually formed by slots and scored, and two side panels of the box joined along the edges by 180 degree folds, the folds or bends being along scores that eventually become the diagonally opposite side corners of the box when the box is erected for filling and the 180 degree bends reduced to right angle bends. Centrally located in regard to each thickness of the blank is a second score or fold line, the score lines of the two thicknesses becoming the other diagonally opposite side corners of the box when erected.

The blanks are formed on a continuous basis, a pair of kraft or other paper liners or face sheets being fed into a corrugating machine, to combine with the corrugating medium produced by the machine to form what is known as double face board, consisting of two face sheets or liners adhesively secured to the loops or arches of the corrugating medium therebetween. The blanks as cut from the double face board are usually squared and of a size to provide the necessary four side panels of a box, the closure flaps and any additional seam portion, such as a lap, as may be required, assuming a lap joint is to be effected.

Blanks folded and joined in the flat form are delivered to the customer in bundles of many blanks stacked one upon the other. Where the manufacturers joint is a lap joint, the lap generally results in extra thickness. Such extra thickness in a stack of blanks prevents the blanks from lying fiat upon one another, and in a bundle, such extra thickness at the lap joint produces a bulge. Even the shipping of a bundle of such blanks entails additional cost due to the bulge of the bundle caused by the multiplicity of extra thicknesses at the lap joint of each blank. Such shipping costs tend to limit the area that can be competitively served by a manufacturer of such cartons. While lapped joints, whether glued or stapled, are structurally sound, the lap prevents neat stacking and is unsightly, whether disposed inside or outside.

The present invention is directed to a blank wherein the joint is of the lap type, but in which the joint is flush with surfaces of the face sheets. The joint, in addition, is admirably suited to employment at the box corner, and the strength of the joint substantially matches that of a lapped manufacturers joint. More particularly, the joint is formed by extended face sheet seam or lap portions which will serve as a lap in the joint to be formed, the lap portions having the corrugating medium removed from between the face sheets. Thus, the fiap or lap is reduced in thickness to that of the liners alone. In order to compensate for such thickness, however, the adjoining portion of the blank is crushed or pressed as by passing between rolls to break the liner connecting portions of the flutes of the corrugating medium, and such pressed portion is allowed to spring back partially to its original thickness, the spring-back being limited, however, by the broken connecting portion, so that the spring-back is short by approximately the thickness of the two liners to be employed in completing the lap joint. In this manner, a flush lap joint of great strength and little extra cost is effected.

The above and other novel features of the invention will appear more fully hereinafter from the following detained description when taken in conjunction with the accompanying drawings. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings, wherein like reference characters indicate like parts:

FIGURE 1 is a plan view of a blank ready for folding into a tube for making the joint;

FIGURE 2 is a sectional view taken on the line 22 of FIGURE 4, with parts broken away because of enlargement;

FIGURE 3 is a view of the joint when folded to a right angle; and

FIGURE 4 is a plan view of a finished blank with the joint completed.

Referring to the drawings, there is shown a box blank after having been slotted and scored, but before the formation of the blank into a jointed flat blank as in FIGURE 4, ready for bundling and shipment to the customer. As shown, the blank comprises a series of side wall panels, in this case of the same. size, as indicated at 22, 24, 26, and 28, such panels being identified by scores 23, 25, and 27, which will be located at three of the box corners when the box is erected. Each panel has integral closure flaps 30 and 32, identified by scorings 34 and 36, such flaps being separated from one another by slots as at as and 40.

The blank, as shown in FIGURE 1, comprises spaced liners or facing sheets 40 and 42, and intervening corrugating medium 44, as indicated in FIGURES 2 and 3. The blank, before slotting and lap cutting, may consist of a rectangular sheet of double faced corrugated board, as produced by standard corrugating apparatus, the dimensions of which are the overall dimensions of the blank shown in FIGURE 1.

Assuming the corrugation of the corrugating medium of the blank extend parallel with the scores 23, 25, and 27, the blank, while being fed in the direction of arrow A, will have the corrugating medium between the lap portions 5052 of the liners removed by a mill, the mill cutting the corrugating media away from between the lap portions 50 and 52 up to the corrugating media edge 54. The lap portions 50 and 52 are thereafter adhesively secured together by adhesive between the lap portions as at 56, lap portion 52 being offset as at 53. While the blank progresses in the direction of arrow A, the left hand edge portion 66 of the panel 22 is subjected to roller or other suitable pressure to squeeze the liners at 60 and 62 together, breaking the corrugating media walls as at 64. The pressure applied is such as to reduce the thickness of the corrugated fiberboard, on spring-back, by the actual combined thickness of the two liner sheets forming the adhesively secured lap portions 50 and 52. The area so pressed extends inwardly from the edge 66 to the offset at 68. When the blank is slotted and creased or scored, the blank is ready for forming and folding into tubular form on the scores 23, 25, and 27, with the laps 50 and 52 folded on score line 29. The offset surface 70 of the liner at 60 between the offset 68 and edge 66, or the inside surface of the lap 52, or both surfaces, are coated with adhesive, and the double lap adhesively applied to the offset portion of the liner. Thereafter, the adhesive is allowed to set and the flush joint created. The blank is then flattened to the form shown in FIGURES 2 and 4 for the delivery in bundles to the customer.

While the invention has been described in regard to a blank wherein the corrugations of the media extend parallel with the scores 23, 25, and 27, which require the removal of the media between the lap portions 50 and 52, the corrugations may extend in the other direction as, for example, parallel with the flap scores 34 and 36. In such case, the corrugating media may, in the formation of the blank at the corrugating apparatus, be of sufficiently less width to provide lap portions without media therebetween, or the media may be removed from between the lap area by a mill running crosswise of the media flutes. The blank before folding and forming the joint will otherwise appear the same as the blank of FIGURE 1, except that the corrugations will extend in the direction of the scores 34 and 36.

In practice, and as one example, each liner may be of a thickness of 0.012 to 0.013 inch, while the corrugating medium is about .009 inch thick. Assuming the overall thickness of the corrugated board to be 0.160 inch, the board is capable of being squeezed in the area 70 to a thickness of 0.040 inch, following which, it will spring back to a thickness of 0.130 inch, providing an offset at 68 of 0.030 inch, adequate to receive the two lap thicknesses 50 and 52 and provide a substantially flush surface at the joint. The two liner thicknesses are readily folded as at 29 to form the corner, and actual scoring for the fold may be light or unnecessary.

Where the corrugations extend parallel with the scores 23, 25, and 27, it will be seen that there is substantially no loss in strength at the manufacturers joint in a direction crosswise of the joint, since the eliminated corrugating media would not add appreciable strength to the tensile strength of the liners. While the joint has been shown as completed adjacent to a corner of the blank, the advantages of the joint would be derived were the joint to be located between two corners and displaced from both.

While the flaps of panel 22 are reduced in thickness as at 72 and 74, no harm is done by such reduction, and in the finished box, such flaps may be inside flaps if desired. On the other hand, should be offset be effected by press action, rather than passage through rolls, the offset area could be reduced to that sufficient to accommodate the laps 50, 52, in which case, the flaps of panel 22 would be of full thickness and free of crushed areas such as 72 and 74.

The joint thus formed is flush externally, and the interior of the box exhibits no lapped members or other evidence of a joint and the raw edge 66 is hidden from view when the box is erected. Whether the corrugations extend parallel with the scores 23, 25, and 27, or parallel with the scores 34 and 36, it generally is the case that the grain of the liners extends crosswise of the corrugations and exhibits greatest strength in the direction of the grain. Thus, the lap, being formed of the thicknesses of both liners, will exhibit substantial strength at the corner, whether the grain extends crosswise or parallel with the corner fold.

While a single embodiment with variations of the invention has been illustrated and described, it is to be understood that the invention is not limited thereto. Various changes in he construction and arrangement may be made without departing from the spirit of the invention, as will be apparent to those skilled in the art.

What is claimed is:

,1. A manufacturers joint for a box formed from a blank of corrugated fiberboard having two liners and corrugating medium therebetween, said joint being formed between the two adjacent edges of a blank having an inner and an outer liner and intervening corrugating medium, one edge of the blank having the liners extended to form lap portions beyond the edge of the intervening corrugating medium, with the inner lap portion of the inner liner being offset outwardly and adhesively bonded to the outer liner to form a lap of the thickness of both liners and of substantial width, and the other edge of the blank having its outer liner pressed inwardly along the edge for a width at least as great as the width of the lap, to provide an offset area, and an offset at least as great as the thickness of the lap, and said lap being secured to the offset area in overlapping relation thereto.

2. A joint according to claim 1, wherein the lap is secured to the offset area by an adhesive.

3. A joint as set forth in claim 1, wherein the lap is so folded at right angles adjacent to the other edge of the blank as to form a corner of the box.

4. A joint as set forth in claim 1, wherein corrugating medium has been removed to form the lap portions and permit the inner lap portion to be offset and adhesively bonded to the outer lap portion to form a lap of two thicknesses of the liner.

5. A joint according to claim 3, wherein the lap is secured to the offset area by adhesive.

6. A joint according to claim 4, wherein the lap is secured to the offset area by adhesive.

7. A joint according to claim 3, wherein the other edge nests in the offset of the inner lap portion and is thereby concealed.

References Cited UNITED STATES PATENTS 1,101,928 6/1914 Hawkins et al.

1,417,776 5/1922 Shafer 22948 X 1,617,274 2/1927 Romer 22948 X 1,698,908 1/1929 Cleveland 22948 1,731,111 10/1929 Romer 22948 2,333,676 11/1943 Robinson 22948 X 3,145,131 8/1964 Finke 22948 X 3,245,604 4/1966 Chapman 22948 3,341,104 9/1967 Loheed.

DAVIS T. MOORHEAD, Primary Examiner,

Images