Fiberboard flat with joined strengthened corners for setting up into an angular tray and the set-up tray

A flat of fiberboard in knocked-down form for setting up into a tray which has strengthened corners. The flat consists of laminated strength-producing connecting corner tabs between hinged side-wall forming flaps. The tabs are formed on the ends of the flaps and some of the flaps are provided with angular fold lines which provide foldable sections in these flaps, the fold lines extending from the flap hinge lines of the respective flaps to a point within the flaps and a slit being provided from that point in each flap to the outer edge of the flap to permit folding of the foldable flap sections.

BACKGROUND OF THE INVENTION AND PRIOR ACT 
This invention relates generally to what are usually referred to in the art 
as trays and which are discussed specifically in U.S. Pat. No. 3,704,824. 
As stated in that patent, these trays are manufactured and sold in flat, 
knocked-down form and are therefore referred to as flats. That patent 
deals with forming strengthened corners in a flat between hinged side-wall 
flaps, the corners consisting of laminated connecting corner tabs which 
are arranged and maintained in superimposed relationship to produce a 
composite laminated flat corner structure, but which will not interfere 
with setting up the tray by merely folding outwardly the various flaps. 
In the example disclosed in said patent, the flat was produced from a 
quadrangular sheet of suitable material scored and slit to provide a flat 
blank with the main flat wall and outwardly-extending hinged flaps at each 
edge thereof, the flaps being separated from each other at specifically 
formed corner slits running outwardly from the corner points of said wall. 
These slits and a pair of special adjacent corner fold score lines 
provided at each flap end, corner-connecting tabs of special form. The 
corner score lines at each corner were disposed at a right angle 
relatively and the slit at each corner extended outwardly from the 
junction of those score lines at an angle of 45.degree. to provide a pair 
of corner-connecting tabs of mainly triangular form. The end of the 
adjacent flap was provided with a scored fold line which extended from the 
corner point, at the junction of the corner score lines, at a 45.degree. 
angle relative to the adjacent corner fold score line and at a right angle 
relative to the corner slit into the flap and angularly to the outer edge 
thereof. Two of the opposed flaps of a first pair were folded inwardly and 
the two flaps of the second pair remained flat and extended outwardly so 
that the corner-connecting tabs were arranged in superimposed relationship 
and were maintained in that relationship by adhesive or otherwise to 
produce a composite laminated structure. The tray was set up for merely 
folding outwardly the first pair of flaps which automatically folded 
inwardly the second flat pair of flaps so that all the flaps were 
upstanding relative to the main flat wall. At the corner joints so 
produced by the connected tabs, there were two thicknesses of material 
with the tabs extending inwardly from the corner fold lines in opposite 
directions and overlapping the adjacent angularly disposed flaps which 
provide the side walls of flanges of the tray. 
SUMMARY OF THE INVENTION 
In order to be able to set up the flat into a tray, as indicated, by 
upstanding the flaps, the angular fold lines in the unfolded flat second 
or inner pair of flaps must be at angles of 45.degree. relative to the 
adjacent corner fold score lines and substantially at right angles to the 
adjacent corner slits and these angular scored fold lines cannot converge 
within the flap, unless special provision is made to permit flap folding 
at said angular fold lines. It has been found that whether or not these 
angular scored fold lines converge before extending to the outer edge of 
the flap depends on the dimensions of the flap in which they are formed, 
that is, the relationship of depth of the flap to length of the flap. If 
they converge at any point within the flap, it is necessary to provide a 
separation in the flap extending from the point of convergence to the 
outer edge of the flap, this separation preferably being in the form of a 
slit extending from the convergence point to the outer edge of the flap. 
Without this separation in the flap material, it would be impossible for 
the first pair of flaps to be folded inwardly about the converging angular 
fold lines to bring the connected corner tabs into superimposed flat 
relationship in making the flat and subsequently in setting up the tray 
from the flat and subsequently for the first pair of flaps to be folded 
outwardly upright to pull the second pair of inner flaps upwardly and 
outwardly to the upright positions by the upward folding of the adjacent 
corner-connecting tabs which bend about the angular fold lines. 
In flats for quadrangular trays or trays of even number of side flaps, this 
slit at the flat fold-line convergence point must be provided in 
alternating flaps. In the flats for trays that have uneven number of 
flaps, the slit must be provided in any flap that originally is not folded 
out of the plane of the main wall of the flat which may be termed an inner 
flat flap. But one of the originally flat flaps must be provided with 
independently foldable areas which can be folded in sequence.

DETAILED DESCRIPTION OF THE INVENTION 
With reference to FIG. 1 of the drawings, the completed set-up quadrangular 
tray ready for use according to the present invention is indicated as 
comprising a flat main wall 10 with a peripheral edge wall or flange 11 at 
a right angle to the plane thereof. In this illustration, the tray is 
square, the wall 10 is the bottom and the edge wall 11 is upstanding. In 
this upright position, the tray is suitable for use as a receptacle tray, 
as the bottom telescoping closure of a box or as the lower section of a 
fully telescoping box. In a position inverted from that shown, it is 
suitable for use as top telescoping closure of a box or as the upper 
section of a fully telescoping box. At each of the four corners of the 
tray, a special corner connecting joint 12 is provided which results in a 
double laminated thickness adjacent the corner and especially at the 
vertically disposed corner fold line. However, as indicated, this 
invention is not limited to a four-sided tray. 
The flat for the tray is produced according to this invention, from the 
flat blank illustrated in FIG. 3. This blank may be formed from suitable 
sheets of material, such as corrugated fiber board, solid fiber board, 
paper board, or other sheet material capable of being slit, scored and 
folded. In this example, the blank is shown of square outline and as being 
provided with the main score lines 21a, 22a, 23a and 24a parallel to the 
respective outer edges of the blank and producing the respective hinged 
flaps 21, 22, 23, and 24 of equal length and which extend outwardly from 
the main wall portion 10a so as to be of equal depth. At the corners of 
the blank these adjacent angularly disposed main score lines intersect to 
provide the corner points 25, 26, 27 and 28, corresponding to the corners 
of the resulting flat wall portion 10a. The portions of the respective 
score lines extending beyond these corner points provide at the respective 
corners of the blank, pairs of corner fold lines 25a-25b, 26a-26b, 27 
a-27b and 28a-28b. All of these corner score lines preferably are more 
pronounced in that they are wider than the other score lines of the blank. 
At each corner between the fold lines of each pair of corner fold lines, a 
slit which is mainly diagonal, is made and these slits are designate 25c, 
26c, 27c and 28c respectively. However, the outer end of each slit, 
indicated at 25g, 26g, 27g and 28g, respectively, is turned parallel to 
the respective adjacent corner scored fold line 25b, 26b, 27b or 28b and 
normal to the respective adjacent corner score line 25a, 26a, 27a or 28a. 
An additional angular score line is provided adjacent each corner of the 
blank and these lines are designated 25d, 26d, 27d and 28d, respectively. 
Each of these lines extends diagonally outwardly from the respective 
corner points 25, 26, 27 and 28 in diverging relationship to the 
respective slits 25c, 26c, 27c and 28c. In this square blank, the diagonal 
score lines 25d, 26d, 27d and 28d are at an angle of 45.degree. relative 
to the respective corner fold lines 25a, 26a, 27a and 28a, and the flap 
fold lines 21a, 22a, 23a, and 24a, but the main parts of the substantially 
bisecting slits 25c, 26c, 27c and 28c will be at a slightly greater angle 
relative to these respective corner fold lines and at a lesser angle 
relative to the respective corner fold lines 25b, 26b, 27b and 28b. The 
indicated relative positioning of these diagonal fold lines and corner 
fold lines, results in the formation of foldable areas 25h, 26h, 27h and 
28h on the respective flaps 21 and 23. The result of the described 
arrangement of corner score lines and slits is the formation of a pair of 
corner connecting tabs at each corner including an inner tab and an outer 
tab, the pairs being designated 25e-25f, 26e-26f, 27e-27f and 28e-28f. The 
corner tabs 25f, 26f, 27f and 28f will be the outer tabs in the set-up 
tray while the corner tabs 25e, 26e, 27e and 28e will be the inner tabs 
and are of special form and include the outer extensions 25i, 26i, 27i and 
28i, which extend beyond the slit lines 25c, 26c, 27c and 28c that 
substantially bisects the right angles between the respective pairs of 
corner scores 25a-25b, 26a-26b, 27a-27b and 28a-28b. 
In order to be able to form the proper flat from the square blank of FIG. 3 
and to subsequently set-up the tray of FIG. 1 from that blank, the angular 
scored fold lines 25d, 26d, 27d and 28d must be at angles of substantially 
45.degree. relative to the respective corner fold lines 25a, 26a, 27a and 
28a and these flap fold lines 21d, 22d, 23d and 24d are also at angles of 
substantially 90.degree. relative to the bisecting tab-forming slits 25c, 
26c, 27c and 28c. Therefore, in some instances, as indicated in the square 
blank of FIG. 3, depending on the proportion of length to depth of the 
flap in which these angular fold lines are formed, these angular lines 
will converge in the flap at a point spaced from the outer edge of the 
flap. This would prevent folding at these angular lines during forming and 
gluing of the flat and setting up the tray from the flat. Therefore, some 
means must be provided to permit this folding and this means must be a 
separation of material from the converging point to the outer edge of each 
flap, and this separation may be in the form of a notch or even a weakened 
tear line. Preferably this separation is in the form of a slit which 
extends from the point of convergence to the flap edge and which is 
designated 21s and 23s in the respective flaps 21 and 23 in this square 
blank. 
In forming the flat of FIG. 2 from the blank of FIG. 3, a first pair of 
flaps, consisting of the opposed flaps 22 and 24, is folded upwardly and 
inwardly and then downwardly with the flaps folding about their respective 
fold or hinge score lines 22a and 24a, while the outwardly extending flaps 
21 and 23 are not folded but remain flat and in a common plane with the 
main wall portion 10a. In describing this folding operation, reference 
will be made to one corner only, but it will be understood that the same 
action will occur at each corner. At this one corner, before the flap 24 
is folded inwardly and glued to tab 28e and area 28h, the 
corner-connecting tab 28e, along with the co-planer folding flap area 28h, 
is folded inwardly and upwardly about the diagonal score line 28d and then 
downwardly until it rests on the underlying areas of flap 21 and wall 
portion 10a, as shown in FIG. 2. Folding as indicated about diagonal score 
line 28d is permitted because of slit 21 s. It will be noted that flap 
fold line 21a, corner fold 28a and corner fold line 28b will be in common 
alignment at this time. The outer corner connecting tab 28f remains in a 
common plane with the flap 24 and the flap will be pressed downwardly 
until it will be superimposed on the wall portion 10a and superimposed and 
glued to tab 28e, and the tab 28f will be superimposed and glued on the 
flap area 28h. 
As stated above, before these surfaces of members 28f and 28h, and 24f and 
28e are superimposed and moved into contact, they are coated with suitable 
adhesive and eventually are pressed together so that they will remain in 
an adhered oondition. It will be noted in FIG. 2 that the angular edge 28j 
of the tab 28f will be offset rearwardly of the angular fold line 28d to 
prevent accidental tearing loose of the tab 28f. This is the reason for 
offsetting the diagonal slit 28c of the blank, and corresponding slits at 
the other corners, as described. This offset should be at least as much as 
the thickness of the blank material. The described superimposed adhered 
areas will provide a composite laminated structure of double thickness 
with the corner fold lines 28a and 28b being in superimposed alignment and 
providing a double thickness at the resulting common corner fold line. 
As previously indicated, the inner tab 28e is provided with the extenions 
28i which will project outwardly beyond the diagonal part of the edge 28c 
of the tab. This serves as a reinforcing tab to prevent breaking of the 
flap 24 during set-up of the tray, which might occur along this diagonal 
part of edge 28c. Also, as previously indicated, the corner score lines 
such as score lines 28a and 28b are much deeper and wider than the other 
score lines. This will increase the tendency to fold at these corner score 
lines during setting up of the tray. Also, if during the lamination and 
gluing of the corner joints, the corner score lines 28a and 28b are 
misplaced slightly, they will still partially align since they are so 
wide. 
In setting up the tray of FIG. 1 from the folded flat of FIG. 2, the 
opposed flaps 22 and 24 are folded outwardly and upwardly about their 
respective hinge lines 22a and 24a and the opposed flaps 21 and 23, 
because of the previously joined corners, are automatically folded 
inwardly about the respective fold lines 21a and 23a. As the flap 24 folds 
upwardly and outwardly, the outer corner tab 28f moves upwardly therewith 
and at the same time, folds inwardly about the corner fold line 28b at a 
right angle relative to the flap 24. The inner corner tab 28e, being 
secured to the flap 24, also moves outwardly with that flap and bends at 
the corner fold-line 28a. Simultaneously, the flap 21 is raised about the 
fold line 21a and moved inwardly and also bending about the angular fold 
line 28d until the flap area 28h, which bends about corner fold line 28a, 
is in a common plane with the main part of the flap 21. Because of the 
provision of slit 21a in flap 21 folding above angular line 28d is 
permitted. Also because of the provision of the wider and deeper corner 
score lines and the reinforcing extensions 25i, 26i, 27i and 28i on the 
inner flaps, the material of the flaps 22 and 24 will not tend to break 
along the angular lines 25c, 26c, 27c and 28c at the inner edges of 
connecting tabs 25e, 26e, 27e and 28e. Thus, all of the flaps 21, 22, 23 
and 24 will be readily positioned upright substantially at right angles to 
the plane of the bottom portion 10a and provide the peripheral edge wall 
or flange 11. 
It will be understood that each corner joint 12 (FIG. 1) will be of 
double-thickness at the final vertical corner fold-lines. The inner corner 
connecting tabs 25e, 26e, 27e and 28e, which are disposed inside the 
respective flaps 22 and 24 and are adhered to the inner surfaces thereof, 
in combination with the outer corner connecting tabs 25f, 26f, 27f and 
28f, which overlap the respective flaps 21 and 23 and are adhered to the 
outer surfaces thereof, will provide a composite double laminated corner 
connecting structure. Since the overlapping layers, including the 
oppositely extending inner and outer corner-connecting tabs, which are 
disposed relatively at right angles, are adhered to adjacent surfaces of 
the side flaps, they serve to provide a composite laminated structure 
having a strength in combination greater than the sum total of the 
strength of each of the layers. 
Since the flat is manufactured and supplied in the knocked-down condition 
illustrated in FIG. 2, storage and shipping will be facilitated as it will 
occupy a minimum of space. In the example shown, the flat can easily be 
set-up for use merely by outward folding of the one pair of flaps, which 
will automatically produce inward folding of the other pair, due to the 
previously joined corner structures. When set up, the corners will be of 
increased strength because of the adhered laminations providing double 
thickness of material at the corner fold lines. After some uses, the tray 
could again be knocked-down for storage. 
As indicated in the following examples, this invention is applicable to 
angular trays of other than four sides, where there are angularly related 
side walls and it is desirable to provide connecting joints of increased 
strength at the angles between said side walls. Although in the square 
example given, it is preferred to provide the reinforcing extensions 25i, 
26i, 27i and 28i on the inner flaps 25e, 26e, 27e and 28e, these may be 
eliminated and the tabs will be of triangular form. Also, in this square 
example, it is preferred to provide the offset angular edge 28j on tab 28f 
and similar offsets on the other corresponding tabs, but these can be 
eliminated. Therefore, in the following examples for sake of simplicity of 
disclosure, these reinforcing extensions and offset edges will not be 
described, but could be present. 
In FIG. 4, there is illustrated an embodiment of this invention in the form 
of a tray of regular octagonal form. The blank for producing this tray is 
shown in FIG. 6 and is provided with the main score lines 31a, 32a, 33a, 
34a and 35a, 36a, 37a and 38a parallel to the respective outer edges of 
the blank to produce the respective eight hinged side wall forming flaps 
31, 32, 33, 34, 35, 36, 37 and 38 which in this example are of equal 
length and extend outwardly from the main flat portion 30a so as to be of 
equal depth. At the corners of the blank, these adjacent angularly 
disposed score lines interest to provide the corner points 41, 42, 43, 44, 
45, 46, 47 and 48 corresponding to the corners of the resulting flat wall 
portion 30a. At the respective corners of the blank, pairs of wide corner 
fold lines 41a-41b, 42a-42b, 43a-43b, 44a-44b, 45a -45b, 46a-46b, 47a-47b, 
and 48a-48b are provided. Each of these pairs is bisected by a slit 
designated respectively 41c, 42c, 43c, 44c, 45c, 46c, 47c and 48c. Each 
slit extends outwardly from its respective corner point and with the 
associated corner fold lines provides the respective pairs of corner tabs 
of triangular form which are designated 41e-41f, 42e-42f, 43e-43f, 
44e-44f, 45e-45f, 46e-46f, 47e-47f, 48e-48f. The alternating flaps 31, 33, 
35 and 37 are provided with additional angular scored fold lines arranged 
in converging pairs in each flap and designated respectively 31d, 33d, 35d 
and 37d in the respective flaps. It will be noted that each of these pairs 
converging at a point which is midway of the length of the flap and spaced 
inwardly from the outer edge of that flap. This is because each of these 
flap fold lines, as previously indicated, must be at substantially a right 
angle relative to the adjoining corner slit 41c, 42c, 43c, 44c, 45c, 46c, 
47c and 48c, which slits substantially bisect the respective spaces 
between the pairs of corner fold lines 41a-41b, 42a-42b, 43a-43b, 44a-44b, 
45a-45b, 46a-46b, 47a-47b and 48a-48b. As previously indicated, to permit 
folding of the respective alternating flaps 32, 34, 36 and 38 in making 
the flat, gluing and setting up the tray from the flat, a separation, 
preferably in the form of a slit, extends from the point of convergence of 
the angular fold lines to the outer edge of the respective flap. These 
slits are designated 31s, 33s, 35s and 37s, respectively. As the angle 
between adjacent flap hinge lines, such as 31a and 32b increases the point 
of convergence of fold lines, 31d will move inwardly towards the hinge 
line 31a and the depth of slot 31s will necessarily increase. For example, 
in the square form of FIG. 3, such an angle is a right angle and in this 
octagon form the angle increases to an obtuse angle. 
In forming the flat of FIG. 5 from the blank of FIG. 6, the alternating 
flaps 32, 34, 36 and 38 are folded upwardly and inwardly and then 
downwardly with the flaps folding about their respective fold or hinge 
lines 32a, 34a, 36a and 38a while the outwardly extending flaps 31, 33, 35 
and 37 are not folded, but remain flat and in a common plane with the main 
wall portion 30a. In describing this folding operation, reference will be 
made to one corner only as before. At this one corner before the flap 38 
is folded inwardly and glued to the tab 48e and foldable flap area 48h, 
the corner-connecting tab 48e along with coplanar flap area 48h is folded 
inwardly and upwardly about the angular score line 31d and then downwardly 
until it rests on the underlying areas of flap 31 and wall portion 30a as 
is shown in FIG. 5. Folding as indicated about angular score line 31d is 
permitted because of slit 31s. It will be noted that corner fold line 48a 
and corner fold line 48b will be in common alignment at this time. The 
outer corner connecting tab 48f remains in a common plane with the flap 38 
and the flap 38 will be pressed downwardly until it will be superimposed 
on the wall portion 30a and superimposed and glued to tab 48e and the tab 
48f will be superimposed and glued on the flap area 48h. When the 
corner-connecting tab 41e at the opposite corner, along with coplaner flap 
area 41h is folded upwardly and inwardly about the angular score line 31d 
and then downwardly, this foldable area 41h overlaps foldable flap area 
48h, which is permitted because of slit 31s. The flat of FIG. 5 is set up 
into the tray of FIG. 4 substantially in the same manner as setting up the 
flat of FIG. 2 into the tray of FIG. 1. 
In FIG. 7, there is illustrated another embodiment of the invention in the 
form of a tray of irregular octagonal form. The blank for producing this 
tray is shown in FIG. 9 and is provided with the main score lines 51a, 
52a, 53a, 54a, 55a, 56a, 57a and 58a parallel to the respective outer 
edges of the blank to produce the respective eight hinged side-wall 
forming flaps 51, 52, 53, 54, 55, 56, 57 and 58 which extend outwardly 
from the main flat wall portion 50a and are of equal depth. However, the 
flaps 51 and 55 are of greater length than the others. At the corners of 
the blank, these adjacent angularly disposed score lines intersect to 
provide the corner points 61, 62, 63, 64, 65, 66, 67 and 68 corresponding 
to the corners of the resulting flat wall portion 50a. At the respective 
corners of the blank, pairs of wide corner fold lines 61a-61b, 62a-62b, 
63a-63b, 64a-64b, 65a-65b, 66a-66b, 67a-67b and 68a-68b are provided. 
Each of these pairs is bisected by a slit designated respectively 61c, 
62c, 63c, 64c, 65c, 66c, 67c, and 68c. Each slit extends outwardly from 
its respective corner point and with associated corner fold lines provides 
the respective pairs of corner tabs of tri-angular form which are 
designate 61e-61f, 62e-62f, 63e-63f, 64e-64f, 65e-65f, 66e-66f, 67e-67f 
and 68e-68f. The alternating flaps 51, 53, 55, and 57 are provided with 
additional angular scored fold lines arranged in pairs in each flap and 
designated respectively 51d, 53d, 55d and 57d. In the opposed longer flaps 
51 and 55, the pairs of angular fold lines 51d and 55d do not converge 
within the respective flap because the flaps are relatively long compared 
to their depth. Thus, triangular foldable flap area 61h-68h and 64h-65h 
are formed. However, in the opposed shorter flaps 53 and 57, the angular 
fold lines 53d and 57d do converge within the respective flaps forming 
flap areas 62h-63h and 66h-67h with slits 53s and 57s. This is because 
each of the angular flap fold lines must be substantially at a right angle 
relative to the adjacent corner slit 61c, 62c, 63c, 64c, 65c, 66c, 67c and 
68c, which slits substantially bisect the respective spaces between the 
pairs of corner fold lines 61a-61b, 62a-62b, 63a-63b, 64a-64b, 65a-65b, 
66a-66b, 67a-67b and 68a-68b. As previously indicated, to permit folding 
of the respective flap areas of flaps 53 and 57 in which the flap fold 
lines 53d and 57d converge, during the making and gluing of the flat, and 
setting up the tray from the flat, a separation, preferably a slit, 
extends from the point of convergence of the angular fold lines to the 
outer edge of the respective flaps. These slits are designated 53s and 57s 
and are mentioned above. 
FIG. 9 brings out that whether or not such slits are needed depends on the 
proportion of length to depth of the flap. Also, that such slits are 
necessary in an irregular shaped octagon. 
To fold and glue the blank of FIG. 9 into the flat of FIG. 8, each corner 
is folded in substantially the same manner as previously described with 
reference to the blank of FIG. 6, with the exception that the slits in 
flaps 51 and 55 are not necessary because angular fold lines 51d and 55d, 
in the respective flaps, do not converge within the flaps because of the 
proportion of flap length to flap depth as mentioned above. The flat of 
FIG. 8 is set up into the tray of FIG. 7 substantially in the same manner 
as setting up the flat of FIG. 5 into the tray of FIG. 4. 
FIG. 10 shows a blank for producing a folding flat which can be set up into 
a tray of regular hexagonal form according to this invention. This blank 
is similar to the blank shown in FIG. 6 for the regular octagonal tray 
and, therefore, the flat and the final tray need not be shown and 
described. In this example, all the flaps are of equal length and the 
alternate flaps have the angular flap fold lines as in the regular octagon 
form. Specifically, the blank is provided with the main score lines 71a, 
72a, 73a, 74a, 75a and 76a parallel to the respective outer edges of the 
blank to produce the respective six hinged side-wall forming flaps 71, 72, 
73, 74, 75 and 76 of equal length and depth which extend outwardly from 
the main flat wall portion 70a. The corner points of the flat wall portion 
70a are illustrated at 81, 82, 83, 84 85 and 86 and at these respective 
corners pairs of wide corner fold lines 81a-81b, 82a-82b, 83a-83b, 
84a-84b, 85a-85b, 86a-86b are provided. Each of these pairs is bisected by 
a respective slit 81c, 82c, 83c, 84c, 85c and 86c. Each slit extends 
outwardly from its respective corner and with associated corner fold lines 
provides the respective pairs of corner tabs of triangular form 
81e.varies.81f, 82e-82f, 83e-83f, 84e-84f, 85e-85f and 86e-86f. The 
alternating flaps 71, 73 and 75 are provided with additional angular 
scored fold lines arranged in converging pairs in each flap and are 
designated respectively 71d, 73 d and 75d, each of these being at a right 
angle to its associated slit. Since each of these pairs of fold lines 
converge within its respective flap to permit folding of the blank into 
the flat and setting up of the tray from the flat, it is necessary to 
provide the slits 71s, 73s and 75s extending from the respective 
convergence points to the outer edge of the flap and pairs of flap areas 
71h, 72h, 73h, 74h, 75h, and 76h are thus produced. The flat can be 
produced by folding in the same manner as described with reference to the 
octagon flat of FIG. 5 and the tray set-up therefrom in the manner 
described with reference to FIG. 4. 
With reference to FIGS. 11 to 13, there is shown an embodiment of the 
invention in a tray of an uneven number of sides, specifically five sides 
in this example. For a tray of uneven number of sides, alternate flaps 
fold in and out in the same manner as in the flat for a tray of even 
number of sides, but one flap will be different in that it will include a 
portion which will fold inwardly and a portion which initially remains 
flat and later will fold inwardly. 
The five-sided tray of this example is illustrated in FIG. 11 and is made 
from the folded flat of FIG. 12 which is produced from the blank of FIG. 
13. In this example, all the flaps are of equal length and depth and are 
numbered 91, 92, 93, 94 and 95, and fold about hinge lines 91a, 92a, 93a, 
94a and 95a. They are arranged around the flat main wall portion 90a. The 
corner points of the flat wall portion are numbered 101, 102, 103, 104 and 
105 and at these respective corners pairs of wide corner fold lines 
101a-101b, 102a-102b, 103a-103b, 104a-104b and 105a-105b are provided. 
Each of these pairs is bisected by a respective slit 101c, 102c, 103c, 
104c and 105c. Each slit extends outwardly from its respective corner and 
with associated corner fold lines provides the respective pairs of corner 
tabs of triangular form 101e-101f, 102e-102f, 103e-103f, 104e-104f and 
105e-105f. As before, alternating flaps 91 and 93 are provided with 
additional angular scored fold lines arranged in converging pairs in each 
flap and are designated respectively 91d and 93d. However, in this 
five-sided example, the one flap 94 is different in that it has only one 
scored fold line 94d which extends from corner point 104 at a right angle 
to the corner slit 104c, but terminates inwardly from the outer edge of 
flap 94. From this termination point to the flap edge, a slit 94s is 
provided. This divides the flap 94 into portions 94h and 94k. Also at this 
corner 104, an additional scored fold line 106a is provided which 
converges with corner fold line 104a and aligns with flap hinge line 95a. 
It will be noted that the corner fold line 106a with the angular scored 
fold line 94d provide a foldable flap area 94h. Also, an extra scored fold 
line 106b, in this instance, is provided between the corner slit 104c and 
corner fold line 104b. In the flap 91, the pair of angular fold lines 91d 
with the slit 91s produce the two foldable flap areas 91h and 95h. 
Similarly in the flap 93, the pair of angular fold lines 93d with slit 93s 
provides the foldable flap areas 92h and 93h. 
To fold and glue the blank of FIG. 13 into the flat of FIG. 12, the 
outwardly extending flaps 92, 94 and 95 are folded upwardly and inwardly 
and then downwardly with the flaps folding about the respective hinge 
lines 92a, 94a, 95a, while the outwardly extending flaps 91 and 93 are not 
folded, but remain flat and in a common plane with main wall portion 90a. 
Flap 94 in this example as stated above, has portions 94h and 94k which 
can be folded separately due to the provision of fold lines 94d and 106a. 
To fold and glue corners 102, 102 and 105, substantially the same 
procedure is followed as previously described with reference to the other 
examples. However, corner 104 is different because this tray has an odd 
number of sides and this causes a difference in folding it and corner 103. 
After the coplanar flap areas 104e and 94h of flap 94 have been folded 
about angular fold line 94d and the flap 95 has been folded inwardly and 
glued to the coplaner areas 104e and 94h, it being understood that flap 
portion 94k is in its original flat position, the coplanar flap areas 103e 
and 93h of adjacent flat flap 93 are then folded upwardly, and then 
downwardly. It will be noted that fold line 106a aligns with flap hinge 
line 94a. The flap 94 is now folded upwardly, inwardly and downwardly 
about fold lines 94a, 106a and 106b causing areas 103e and 93h of flap 93 
to be contacted and glued to areas 103f and 94k of flap 94. It will be 
noted that fold line 106 b also aligns with flap hinge line 94a. 
Setting up the tray of FIG. 11 from the flat of FIG. 12 will be 
substantially the same as setting up the flats previously described. 
It will be apparent from the above that this invention provides for the 
production of flats of an equal or unequal number of sides and in each 
flat the corners are laminated in such a manner that when the tray is set 
up therefrom, it has strengthened corners. Angular fold line are provided 
in the side-wall forming flaps which provide foldable flap sections that 
must be folded inwardly. When these lines terminate at a point within the 
outer edges of the respective flaps, the material of the flap must be 
separated or slit at that point. These angular scored fold lines must be 
substantially at a right angle to the respective adjacent corner slits 
which substantially bisect the angles between the adjacent corner fold 
lines to produce the inner and outer corner connecting tabs. In the flats 
for trays of an equal number of sides, the alternating flaps have a pair 
of converging angular fold lines which provide the foldable flap sections 
on the ends of such flaps. In the flaps for trays of an odd number of 
sides, alternating flaps have the pair of converging angular fold lines 
and the final odd flap has only one angular fold line which along with its 
associates flap slit divides that flap into independently foldable flap 
sections which can be folded in sequence. As pointed out, before the flap 
slits extending from the angular fold lines are necessary when the angular 
lines or line terminate within the respective flaps due to the proportion 
of length to depth of the flap. It will be apparent from the drawings that 
as the number of sides of the flat increase, the angle between the flap 
hinge line and the angular fold lines or line associated therewith 
decrease which results in the need for the flap slits.