Corrugated cartons having crush-relieved flaps
US 3122976 A
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March 3, 1964 CORRUGATED CARTONS HAVING CRUSH-RELIEVED FLAPS Filed April 13, 1959 2 Sheets-Sheet 1 H. R. ANDERSON IN VEN TOR. Hopes/9r fl/mapsm Ame ve-Ys March 3, 1964 H. R. ANDERSON 7 CORRUGATED CARTONS HAVING CRUSH-RELIEVED FLAPS Filed April 13, 1959- 2 Sheets-Sheet 2 9 9o. 45 3 43 41:. A 37 45c 454. 43
IN V EN TOR. H5955 AZ Ar/oeqson Arroezvtys United States Patent C) 3,122,976 CGRRUGATED CARTQN HAVING CRUSH- RELIEVED FLARS Herbert R. Anderson, Massapeqna, N.Y., assignor to Tri- Wall Containers, Inc, New York, N.Y., a corporation of New York Filed Apr. 13, 1959, Ser. No. 805,924 2 Claims. (Cl. 358.2)
My invention relates generally to boxes and cartons formed of corrugated paper board material, and more particularly to triple-ply corrugated board blanks having crush-relieved fiaps which are readily bent when erecting the box.
Because of its superior structural and cushioning properties, increased use has been made of three-ply corrugated board for packaging relatively heavy objects or for protecting frail articles in transit. Triple wall board is a development of the Tri-Wall Container Corporation of New York and is manufactured in accordance with US. Patent No. 2,759,523, issued August 21, 1956 to Goldstein et al., the board being identified by the trademark Tri-Wall Pak. Containers of Tri-Wall Pak board have in many cases replaced boxes made of wood and other packaging materials. Tests have shown that even if a loaded box of triple Wall corrugated construction is dropped, it does not shatter like wood but continues to give full protection to its contents.
Corrugated board cartons are ordinarily made from flat blanks which are scored and slotted to define the four side panels and the inner and outer end flaps of the carton. When erecting the carton, the flaps are folded inwardly along the score lines so as to form the bottom and top walls. Because of the great rigidity and strength of triple wall corrugated board, difficulty is often experienced in folding in the flaps, especially in the case of small cartons having narrow flaps. Moreover, the thickness of triple wall board is such that substantial resistance or fight is encountered at the corners in erecting the box.
One expedient heretofore used to reduce fight has been a broad score line to weaken the flap in the bending zone, thereby to minimize bending resistance. However, this has not afforded a satisfactory solution to the problem, for the bending line is then not clearly defined and the flap tends to break unevenly and unpredictably.
Accordingly, it is the principal object of this invention to provide a box blank of corrugated board so constructed as to facilitate bending of the flaps along sharply defined and predictable lines.
More specifically it is an object of the invention to provide a triple wall box blank in which a zone contiguous to a sharply defined score line for the flap is crush-relieved to minimize fight when bending the flap.
Also an object of the invention is to provide apparatus for efficiently forming a combined score line and crush-relieved zone in a corrugating machine.
For a better understanding of the invention as well as other objects and further features thereof, reference is bad to the following detailed description to be read in conjunction with the attached drawing wherein like elements in the several figures are identified by like reference numerals.
In the drawing:
FIG. 1 is a plan view of a corrugated board blank having combined score lines and crush-relieved zones in accordance with the invention.
FIG. 2 is a perspective view of the erected carton.
FIG. 3 is a transverse section taken through the blank along the plane of line 33 in FIG. 1.
FIG. 4 is a perspective view of the scoring, crushing Patented Mar. 3, 1984 and trimming wheels in the output end of the machine.
FIG. 5 is an enlarged detail showing the combined crushing and scoring operation.
Referring first to FIGS. 1 and 3, there is shown a sample blank for a shipping box, the box being made of triple-Wall corrugated paper board material. The blank, as best seen in FIG. 2, is formed by three superposed layers or plies of corrugated material consisting, in successive order, of an outer liner 10, a corrugated fiuting 11, liner 12, fluting 13, liner 14, fluting and inner liner 16.
As will be evident in FIG. 1, the blank is provided with transverse score lines 17 which define the side panels 18, 19, 20 and 21 of the box. The inner and outer end flaps 24 to 31 of the box are formed by longitudinal score lines 22 and 23 and transverse slots 32. Provided at the upper end of the blank is a narrow stitch flap 33. The box is erected in the usual manner to assume the form shown in FIG. 2 by bending the panels and flaps along the score lines. It will be understood that the dimensions of the side wall panels and the flaps will depend on the size of the box.
Contiguous to longitudinal score line 22 in the area of flaps 24 to 27 is a narrow crushed zone 34 and contiguous to longitudinal score line 23 is a like narrow crushed zone 35 in the areas of flaps 28 to 31. Thus each flap is crush-relieved at its score line and may be bent inwardly without difficulty. It must be borne in mind that triple-wall corrugated board formed with A-AA fluting is about of an inch thick, and if made with AAC fluting is about W of an inch thick. This thickness is reduced substantially in the crushed zones to facilitate knuckling. However, since the score line is clearly defined and is of somewhat greater depth than the crushed area, the flap bends exactly along the score line.
In making up a regular slotted carton from the blank shown in FIG. 1, the blank is first folded on the transverse score lines 17 and fiap 33 is stitched. Thereafter the bottom is formed by infolding flaps 24 to 27 as shown in FIG. 2. After the contents are placed in the carton, the top flaps 28 to 31 are infolded. Since the flaps are crush-relieved, no difficulty is encountered in the infolding operations.
The web of triple-wall board may be fabricated in a corrugating and combining machine in the manner disclosed in the above-identified Goldstein et al. patent. From the drying and cooling sections of the combining machine the composite board 36 (FIG. 5) passes to a scoring, trimming and crushing machine in accordance with the invention. This machine, as shown in FIGS. 4 and 5 comprises a pair of shafts 37 and 38 which are journalled in suitable side plates and are driven by an electric motor.
The width of the blank is determined by the spacing between two sets of trimming rolls 39-40 and 41-42 mounted on shafts 37 and 38, each set being provided with coacting knife edges 39a40a and 41a and 42:: which act to shear the edges of the web material.
The longitudinal score lines and contiguous crush zones along the blank are formed by two sets of combined score-crush rolls 4344 and 4546 mounted on shafts 37 and 38. The male rolls 43 and 45 are mounted on the upper shaft 37, each roll having a scoring edge 43a and 45a, a cylindrical crushing iron 43b and 45b and a conical feathering iron 43c and 450. Thus, as best seen in FIG. 5, the web is scored by edge 43a and crushed in the contiguous area by crushing iron 4312, the crush being feathered by iron 430 to prevent an abrupt step between the crush zone and the adjacent uncrushed area.
While there has been shown What is considered to be a preferred embodiment of the invention, it is to be understood that many changes and modifications may be made therein Without departing from the essential features of the invention.'
V/hat is claimed is: i
1. A crushing, score and trimming machine for triplewall corrugated board comprising a pair of motor driven shafts in spacedparallel relation, two sets of trimming rolls mounted on said shafts at spaced positions to trim the edges of board passing through said machine, and two sets of combined score-crush rolls interposed between said trimming rolls on said shafts, each of said sets of score-crush rolls including a first cylindrical roll having a substantially continuous outer surface of substantially constant diameter, said first roll being adapted for supporting board being crushed and scored, and a second cylindrical roll having a substantially continuous outer surface of substantially constant diameter spaced apart from the outer surface of said first roll at a distance less than the thickness of said board and adapted'to crush board supported by said first roll, said second diameter, a conical feathering iron adjacent thereto hav ing a substantially continuous surface, and a scoring edge extending radially from the outer surface of said crushing iron. i
References Cited in the file of this patent UNITED STATES PATENTS 1918 1,278,766 Seymour Sept. 10,
1,708,700 Maier Apr. 9, 1929 2,223,503 Wilson Dec. 3, 1940 2,262,303 Staude Nov. 11, 1941 2,364,342 Bruker Dec, 5, 19.44 2,485,020 Staude Oct. 18, 1949 2,710,134 Schroeder June 7, 1955 2,759,523 Goldstein Aug. 21,