EP0326573B1

EP0326573B1 - Box making apparatus and method

Info

Publication number: EP0326573B1
Application number: EP87906827A
Authority: EP
Inventors: Colin Stutt
Original assignee: LANGSTON EUROPE Ltd
Current assignee: LANGSTON EUROPE Ltd
Priority date: 1986-10-04
Filing date: 1987-10-05
Publication date: 1993-07-14
Anticipated expiration: 2007-10-05
Also published as: EP0326573A1; GB8623896D0; FI92568C; DE3786557D1; FI891589A0; DE3786557T2; FI92568B; WO1988002306A1; FI891589A; JPH02500828A

Abstract

Prior to the assembly of boxes made from blanks of corrugated board consisting of at least one layer of corrugated medium sandwiched between two outer liners, the thickness of the overlapping area of each blank at each side is reduced by means for conveying blanks (L1) in succession past cutting means comprising a first cutter (44; 144) for cutting through an outer layer of each blank to delineate a defined area which will overlap a similar area at an opposite edge of the blank when the blank is assembled into a box, and a second cutter (48; 148) arranged to cut away substantially the entire thickness of the corrugated board over the said defined area.

Description

At one stage during the manufacture of boxes from corrugated board, box blanks are folded along pre-formed crease lines and opposite ends of the blanks are stuck together in overlapped relationship, so as to form a flat tube. A problem that then arises is that when those flat tubes are stacked one on top of another, the overlapped portions, being of double thickness, cause the stack to be uneven in height.
It is usual in box blanks to use double faced corrugated board in which a single layer of corrugated medium is sandwiched between two outer liners, but in larger containers the board may be still thicker, having two or even three layers of corrugated medium. In such a case the extra thickness accentuates the uneven stacking.
Further, when articles to be packed are put into the erected box they may jam against the step formed on the inside of the box by the overlapped portions. It has been proposed in U.S. patent 1,186,087 and in EP 226481A to provide a box made of corrugated board in which overlapped portions of the blank, which form a joint when the blank is folded as mentioned above, are each cut away to reduce their thickness, leaving at each edge portion a liner which overlaps with a full-thickness part of the blank; in this connection particular attention is directed to US 1,186,087 and to Figure 5 of EP 226481A, which disclose an arrangement in which the joint formed by the overlapping edge portions of the blank is spaced from the parallel edges of the box. Neither of those specifications, however, discloses or suggests a practical way of making such box blanks.
In a method of making box blanks according to the present invention, the box blanks are prepared by feeding each blank, along a feed path parallel to the above-mentioned edge portions, past first cutting means which cut through opposite liners at the respective edge portions to delineate the area of each edge portion which will be reduced in thickness, and past disc knives having their cutting edges substantially parallel to the blanks to cut away the required parts of the liners and adjacent corrugated medium as the blank moves along the feed path. This enables the cut-away portions of the blank to be removed as continuous pieces, which facilitates their clean and efficient removal, as opposed to a milling or planing process such as is illustrated in the present application (Figures 4, 5 and 7) and also in US 1,430,287 (Figure 3).
An example of a method and of apparatus in accordance with this invention is described below with reference to the accompanying drawings. In these drawings:

Figure 1 is a plan of a box blank having defined areas which have been reduced in thickness,
Figure 2 is a section on the line II-II of Figure 1,
Figure 3 is a section through the blank, similar to Figure 2, but after the blank has been folded into a flat tube,
Figure 4 is a diagrammatic side view showing one form of apparatus for reducing the thickness of the defined areas of the blank of Figure 1, which apparatus, however, does not include all features of the present invention,
Figure 5 is a plan view of part of the apparatus shown in Figure 4,
Figure 6 is a section on the lilne VI-VI in Figure 5, drawn to a larger scale,
Figure 7 is a section on the line VII-VII in Figure 5, drawn to a larger scale, and
Figure 8 is a sectional view of a modification, including the present invention, of the apparatus shown in Figures 4 to 7.

Referring to Figures 1 to 3 of the drawings, 2 is a box blank made from double faced corrugated board consisting of a single layer C of corrugated medium sandwiched between two flat outer lines L1, L2. The blank has parallel score lines 4 and 6 extending between the blank edges 8 and 10; opposed pairs of transverse slots 11, 12, 14 and 16 extending between the score lines and the blank edges 18, 20; and score lines 21, 22, 24 and 26 aligned with and extending between respective slots 11, 12, 14 and 16. Flaps 28 and 30 (the edge portions of this invention) extend respectively from the edges 8 and 10, the flaps being reduced in thickness over their whole areas, from opposite faces of the blank, as shown in Figure 2, at each end of the blank. The blank 2 is then folded, in known manner, along crease lines 21, 22, 24 and 26 to form the blank into a flat tube so that the remaining parts of flaps 28 and 30 overlap, and are stuck to, the opposite ends of the blank, as shown in Figure 3.
Reference will now also be made to Figures 4 to 7 of the drawings. Box blanks are fed in the direction of the arrow A in Figure 4 from printing and slotting apparatus (not shown) of any known form, one at a time and spaced apart in the direction of feed. The blanks are as described above except that, at this stage, the flaps 8, 10 have not been reduced in thickness, and thus are as shown in dotted lines at B in Figure 2. Each blank, lying flat, is fed with the liner L1 uppermost and edge 18 leading, towards two pairs of belts which are spaced apart across the width of the blank so that the edges 8, 10 extend beyond the belts. Each pair of belts consists of respective upper and lower belts 32 and 34 between adjacent runs of which a blank is gripped and fed along a feed path defined by the adjacent runs of the belts, the belts extending between respective pulleys 36,38 (Figure 4).
Whilst a blank is being fed by the belts 32, 34 the flaps 28, 30 are reduced in thickness over their whole areas by cutting away one of the liners L1, L2 and substantially the whole of the layer C, by means of respective cutting units indicated generally at 40 and 42. As the units 40, 42 are very similar, in the following description the same reference number will be used for like parts in both units but with 100 added to the parts of unit 42.
Each unit 40, 42 consists of a first circular cutter 44, 144 fixed on a shaft 46, 146 and, downstream therefrom, a second circular cutter 48, 148 fixed on a shaft 50, 150.
The shafts 46, 50 and 146, 150 are driven by means of respective belts 52, 54 and 152, 154 from motors 56, 156, so that the peripheral speed of the cutters 44, 144, 48, 148 is 10 to 12 times faster than the speed at which the blanks are fed by the belts 32, 34, with all the cutters rotating in a vertical plane. As viewed in Figure 4 the cutters 44, 48 rotate in an anti-clockwise direction, and the cutters 144, 148 rotate in a clockwise direction. The shafts 46, 50 are mounted so that the cutters 44, 48 are positioned below the feed path of the blanks and the shafts 146, 150 are mounted so that the cutters 144, 148 are positioned above the feed path. Each cutter is provided with a number of cutting edges 58 in a similar manner to that of a milling cutter. Positioned above each of the cutters 44, 48 is a respective suction box 60, 61 having slots 62, 63 in their bottom sides (see Figures 6 and 7) and to which suction is applied through pipes 64, 65. Similarly, positioned below each of the cutters 144, 148 is a respective section box 90, 92 having slots 94, 96 in their top sides and to which suction is applied through pipes 98, 100. A fixed plate 66 is positioned as shown in Figures 4, 5 to help support the blank near the edge 8 thereof, and a further fixed plate 68 supports the edge 10 of the blank.
The operation of the apparatus will now be described by following the passage of a single blank through the apparatus. After having printing and slotting operations performed on it, the blank is fed towards the cutters 44, 144. The latter are positioned so that when they engage the respective flaps 28, 30, they do so in line with the edges 8, 10 of the blank. Just prior to the flap 8 engaging the cutter 44, suction is applied through the slot 62 so as to hold the flap flat as it passes the cutter. On engaging with the leading end of the flap 28 the cutter starts to cut through the bottom liner L2 and also the corrugated liner C, leaving the top liner L1 uncut, as shown in Figure 6. As the blank continues to be fed by the belts 32, 34, the cutter 44 makes a narrow cut 70 (the cutter may be, for example, 3mm wide) along the blank, at the base of the flap 28, in line with the edge 8. When the trailing end of flap 28 passes out of engagement with the cutter 44, the area of flap 28 which is to be reduced in thickness is delineated from the rest of the blank by the narrow cut 70. Also the flap 28 passes away from the suction box 60.
Simultaneously with the cut 70 being made, the cutter 144 makes a similar cut 72 at the base of the flap 30, in line with the edge 10 of the blank. However, in this case, as it is positioned above the blank, the cutter 144 cuts through the top liner L1 and also the corrugated layer C, leaving the bottom liner L2 uncut. The area of flap 30 to be reduced in thickness is thus delineated from the rest of the blank by the cut 72. Whilst the latter is being made, the flap 30 is held flat by suction applied to the suction box 90.
As the blank continues to be fed by the belts 32, 34 the flap 28 engages the cutter 48 which progressively removes the remaining portions of the liner L2 and the corrugated layer C from that flap. During this operation the flap 28 is held against the bottom of the box 61 by suction applied through the slot 63. Simultaneously, the cutter 148 removes the remaining portions of the liner L1 and the corrugated layer C from the flap 30, with the flap being held flat by suction applied to the suction box 92. Thus when the flaps 28, 30 pass out of engagement with the respective cutters 48, 148, the flaps 28, 30 comprise only the liners L1 and L2 respectively.
The waste material removed by the cutters 44, 48 is guided by baffle plates 74 (Figure 4) so that it falls into a trough 76 and is carried away for disposal. For this purpose the trough 76 may be vibrated, or may form part of any suitable type of air conveyor. A similar trough (not shown) is provided to collect waste material removed by the cutters 144, 148. Alternatively the waste material may be removed by means of suction pipes (not shown) positioned adjacent the cutters, as is well known in the box making industry.
After passing away from the cutters 48, 148 the blank is fed to further apparatus (not shown) which forms the blank into a flat tube, as described above.
Figure 8 illustrates a modification of the apparatus in accordance with the present invention. The cutter 144 is replaced by a disc knife 77 fixed on the shaft 146, and the cutter 148 is replaced by a disc knife 78 fixed on a shaft 80 mounted at right angles to the shaft 146 so that the knife 78 rotates in a horizontal plane parallel to the blank. In this case the knife 77 makes a cut in the same position as the narrow cut 72 described above, and the knife 78 cuts through the corrugated layer C forming the flap 30 parallel to the liner L2 and as close to that liner as possible without damaging it. The knife 78 extends into the cut made by the knife 77, so that when the flap 30 passes away from the knife 78 the waste material is removed in one piece in any suitable way. The cutter 48 shown in Figure 7 is similarly replaced, in accordance with this invention, with a disc knife.
In the following claims, the reference numerals are quoted purely by way of example and are not intended to limit the scope of the claims.

Claims

A method of making box blanks of corrugated board, to form flat-folded boxes of which overlapping edge portions adhering to one another each have part of one lining and the adjacent part of the corrugated medium cut away so that the remaining lining of each edge portion will overlap with a full-thickness part of the other edge portion of the blank, characterised in that the box blanks (2) are prepared by feeding each blank along a path parallel to the said edge portions (28, 30), past first cutting means (77) which cut through opposite liners at the respective edge portions to delineate the area of each edge portion which will be reduced in thickness, and disc knives (78) having their cutting edges substantially parallel to the blank to cut away the required parts of the liners and adjacent corrugated medium as the blank moves along the feed path.
Apparatus for preparing box blanks of corrugated board used for forming flat-folded boxes of which overlapping edge portions adhering to one another each have part of one lining and the adjacent part of the corrugated medium cut away so that the remaining lining of each edge portion will overlap with a full-thickness part of the blank, characterised by means (32, 34, 36, 38) for conveying successive blanks (2) along a feed path extending past first cutting means (77) arranged to cut through opposite liners of the respective edge portions (28, 30) of the blank to delineate the areas of the edge portions which are to be reduced in thickness, and past second cutting means (78) in the form of disc knives having their cutting edges substantially parallel to the blanks to cut away the required parts of the liners and adjacent corrugated medium of each blank as it moves along the feed path.