Method and machine for forming cases with polygonal section made from a sheet material and cases thus obtained

A method and machine for forming a case with polygonal section from a blank of sheet material. There is an assembly of panels. The assembly of panels is wound about a mandrel with polygonal section. The tongue is fixed to the free edge of the endmost panel. The flaps situated on the same side of the panels are folded. The flaps thus folded are fixed together.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a method and machine for forming 
cardboard, corrugated cardboard or similar sheet material cases, having a 
polygonal section and particularly a square or rectangular section. 
2. Description of the Prior Art. 
Cases of this type are formed from a single blank of said sheet material, 
comprising an assembly of panels (at least three) connected together by 
parallel fold-lines and provided laterally with flaps, connected 
respectively to said panels by fold-lines perpendicular to the fold-lines 
connecting said panels together and intended to form the bottom and the 
lid of said cases. The free edge of one of the endmost panels of said 
assembly is provided with a tongue connected to said endmost panel by a 
fold-line parallel to those connecting said panels together and intended 
to be fixed against the free edge of the opposite endmost panel. 
Known cases of this type are called "American" and they have a square or 
rectangular section (transversely to said boards). They are manufactured 
by an industrial cardboard maker who, from said blank forms a flattened 
tubular blank by folding said blank about the median fold-line of said 
assembly of panels and fixing said tongue to the opposite endmost panel. 
At that time, said model has then a section in the form of a flattened 
parallelogram, said lateral flaps extending the corresponding panels 
respectively outwardly. Then, these flattened blanks are delivered to the 
user who, in order to house therein objects to be packed, puts them into 
shape by expansion parallel to the flattened diagonal of said 
parallelogram then folds back and glues said flaps so as to form the 
bottom and, after filling, the lid of said case. 
Such a procedure for manufacturing and use has numerous drawbacks; In fact: 
of course, both manufacture of the flattened blank by the cardboard maker 
and the shaping of said blanks by the user are achieved by means of 
automatic machines. It can then be seen that it is necessary to use two 
complex and so expensive automatic machines, which adds to the cost of 
using said cases. 
bacause of the lateral flaps, it is difficult to strictly guide the edges 
of the blank at the moment of fixing the tongue on the opposite endmost 
panel, so that squaring is poor and the bonding line obtained is not 
strictly parallel to the fold-lines joining said flaps together; the 
section of the case is therefore not strictly identical between the bottom 
and the lid and the result is defects in the presentation of the cases, 
which adversely affects the quality thereof. 
the flattened blanks have an extra thickness in the middle since the 
flattened blank comprises locally three thicknesses instead of two. This 
extra thickness results in unbalancing the stacks of blanks formed for 
storage and transporting said blanks. The result is difficulties in 
handling said stacks. 
because of the above mentioned extra thicknesses, the number of flattened 
blanks which can be housed in the feed magazine of the shaping and filling 
machine on the user's premises is limited. 
the intermediate fold-lines of the panels are bent to a maximum during 
formation of the flattened blanks; in addition, the intermediate 
fold-lines form external edges of said blanks. Consequently, they are 
weakened by flattening the blanks and subject to external aggressions. The 
result is that these intermediate fold-lines form lines of lesser strength 
for said cases. 
the boards of said cases are necessarily four in number and identical two 
by two, 
because of inaccuracies in fixing and because the edges are made fragile, 
it is necessary to use high quality sheet material. The cost of said cases 
is therefore high. 
SUMMARY OF THE INVENTION 
The purpose of the present invention is to overcome these drawbacks. It 
makes it possible to form a case of the above type completely directly 
from the blank of sheet material, without passing through the intermediate 
stage of forming the flattened blank. Thus, the present invention makes it 
possible: 
to suppress the automatic machine for folding and bonding the flattened 
models on the cardboard maker's premises, 
to store and transport said blanks in the flat condition, so that the 
drawbacks due to the above mentioned extra thicknesses is eliminated, 
namely the difficulties of handling and limitations in supplying the user 
machine (in fact, the capacity of the magazine thereof is multiplied by 
three, for equal height); the machine has then a much longer independent 
operating time, 
from the foregoing, it follows that the intermediate fold-lines are no 
longer lines of weakness, 
to manufacture cases having any number of panels (at least three) and whose 
boards may have different widths; 
to manufacture high quality cases in so far as squaring and the strictness 
of the inner dimension is concerned, even with lower quality sheet 
materials. 
For this, in accordance with the invention, the method for forming a 
polygonal section case from a sheet material blank comprising an assembly 
of panels connected to each other by parallel fold-lines and provided with 
lateral flaps, connected respectively to said panels by fold-lines 
perpendicular to the fold-lines connecting said panels together and 
intended to form respectively the bottom and the lid of said case, the 
free edge of one of the endmost panels of said assembly of panels being 
provided with a tongue connected to said endmost panel by a fold-line 
parallel to the fold-lines connecting said panels together is remarkable 
in that: 
said assembly of panels is wound on a mandrel with polygonal section, whose 
external section corresponds to the inner section of said case to be 
obtained, so that each of the panels is applied against a face of said 
mandrel and so that said fold-lines connecting the panels together bear 
against a corresponding edge of said mandrel, 
said tongue is fixed to the free edge of the other one of said endmost 
boards of said assembly of boards, 
the flaps situated on the same side of said panels are folded down against 
a corresponding face of said mandrel, about corresponding fold-lines which 
are in correspondence with edges of said mandrel, and 
said flaps are fixed together. 
Thus, with the invention, the case may be formed from said blank at the 
moment when it is desired to use it, e.g. for packing a product. 
In an advantageous embodiment, said mandrel is disposed in a fixed station 
and said blank is brought to said mandrel by a translational movement, in 
a direction parallel to said fold-lines connecting said panels together. 
In addition, it is preferable, during winding of said assembly of panels 
about the mandrel and folding of said flaps thereon, for at least one of 
said panels to be horizontal. Thus, it may rest on a table disposed under 
said mandrel. It is then advantageous for the direction of the 
translational movement bringing said blank to be also horizontal, so that 
the blank may be brought to said mandrel and positioned thereunder by 
simple sliding over the table. 
In order to avoid the drawbacks of a fault in the accurate positioning of 
the blank with respect to the mandrel, which could possibly cause the 
blank to be folded along lines different from the pre-formed fold-lines, 
it is advantageous, for winding said assembly of panels about said 
mandrel, to place an intermediate panel of said assembly of panels at 
least approximately opposite the corresponding face of said mandrel, but 
at some distance therefrom, then to fold the panels adjacent said 
intermediate panel and to bring said intermediate panel towards said 
corresponding face. Thus, a possible shift between the blank and the 
mandrel can be compensated for. 
Moreover, particularly for removing the blank from the mandrel, the face of 
the mandrel against which said flaps are folded is made movable. 
Said tongue may be fixed to the free edge of said other endmost board 
and/or said flaps may be fixed together by glueing. 
The present invention also provides a machine for forming a case with 
polygonal section from a sheet material blank comprising an assembly of 
panels joined together by parallel fold-lines and having lateral flaps 
connected respectively to said panels by fold-lines perpendicular to the 
fold-lines connecting said panels together and intended to form 
respectively the bottom and the lid of said case, the free edge of one of 
the endmost boards of said assembly of panels being provided with a tongue 
connected to said endmost panel by a fold-line parallel to the fold-lines 
connecting said panels together, this machine being remarkable in that it 
comprises 
a mandrel with polygonal section whose external section corresponds to the 
inner section of the case to be obtained, 
means for winding said assembly of boards about said mandrel so that each 
of said panels is applied against a face of said mandrel and so that said 
fold-lines connecting said panels together bear against a corresponding 
edge of said mandrel, 
means for fixing said tongue to the free edge of the other one of said 
endmost panels of said assembly of boards, 
means for folding the flaps situated on the same side of said panels 
against a corresponding face of said mandrel, about corresponding 
fold-lines which are in correspondence with edges of said mandrel, and 
means for fixing together said flaps thus folded. 
Preferably, the machine of the invention comprises a horizontal table 
disposed under said mandrel and means for bringing said blank under said 
mandrel, by sliding over said table, as well as means for locally glueing 
said blank when it is brought under the mandrel. 
It is advantageous for it to comprise means for placing said case upright 
for its removal. The machine may comprise means for ejecting the case from 
the mandrel, formed at least partially by said face of the mandrel against 
which said flaps are folded. 
In an advantageous embodiment, in the machine of the invention, said means 
for winding said panels about the mandrel comprise a mobile assembly, 
having fixed stops and swinging arms.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The sheet material blank, made for example from cardboard or corrugated 
cardboard, shown in FIG. 1a comprises an assembly of four aligned panels 
2, 3, 4 and 5, connected together two by two by pre-formed and parallel 
fold-lines 6, 7 and 8. These parallel fold-lines 6, 7 and 8 are disposed 
respectively between panels 2 and 3, 3 and 4, 4 and 5. Along the free edge 
of the endmost panel 2 of said assembly of panels 2 to 5 is disposed a 
tongue 9, connected to said endmost panel 2 by a fold-line 10, parallel to 
fold-lines 6, 7 and 8. 
Furthermore, on each side of each panel 2 to 5 are provided flaps 11.2, 
11.3, 11.4, 11.5 and 12.2, 12.3, 12.4, 12.5. Each side flap 11.2 to 11.5 
is hinged to the corresponding panel 2 to 5 by a pre-formed fold-line 13.2 
to 13.5. The fold-lines 13.2 to 13.5 are aligned and are perpendicular to 
the fold lines 6, 7 and 8. Similarly, each side flap 12.2 to 12.5 is 
hinged to the corresponding panel 2 to 5 by a pre-formed fold-line 14.2 to 
14.5. The fold-lines 124.2 to 14.5 are aligned and perpendicular to the 
fold-lines 6, 7 and 8. 
Lines of adhesive 16, 17 and 18 are deposited both on the upper face (with 
respect to FIG. 1a) of the endmost panel 5, along the free edge 19 thereof 
and on the lower face (with respect to FIG. 1a) of flaps 11.2 and 11.4. 
According to the invention (see FIG. 1b) a mandrel 19 is provided whose 
external shape corresponds to the internal shape of the case to be 
obtained from blank 1. Such a mandrel may be solid or formed solely of a 
frame defining its edges. 
Blank 1 is disposed with respect to mandrel 19 so that its board 3 is 
applied against the corresponding lower face of the mandrel, then panels 2 
and 4 are folded about the edges thereof corresponding to fold-lines 6 and 
7, so as to be applied against the corresponding said faces of the mandrel 
19 (see FIG. 1b). After, that panel 5 and tongue 9 are folded respectively 
about the edges of said mandrel corresponding respectively to the 
fold-lines 8 and 9, so as to be applied on the upper face of said mandrel 
19, tongue 9 being under panel 5 (see FIG. 1c). A pressure exerted on 
board 5 applies edge 19 thereof on said tongue so that, with the line of 
adhesive 16, panel 5 and tongue 9 are joined together. In addition, flaps 
11.2 and 11.4 are folded about the edges of the mandrel 19 corresponding 
respectively to the fold-lines 13.2 and 13.4 so as to be applied against 
the corresponding side face of mandrel 19 (see also FIG. 16). 
In this position, the lines of adhesive 17 and 18 are directed outwardly. 
Finally, flaps 11.3 and 11.5 are folded about the edges of mandrel 19 
corresponding respectively to the fold-lines 13.3 and 13.5 and are applied 
against the flaps 11.2 and 11.4, already folded, so that said flaps 11.2 
to 11.5 are joined together, because of the lines of adhesive 17 and 18 
(see FIG. 1d). Then the case 20 shown in FIG. 1d is obtained, resting on 
panel 3 and open on the side of flaps 12.2 to 12.5. 
For filling this case 20, it is released from mandrel 19 and it may be 
placed upright so as to rest on its bottom 21 formed by flaps 11.2 to 11.5 
joined together. After filling, the case 20 may be closed by folding flaps 
12.2 to 12.5 respectively about fold-lines 14.2 to 14.5, then flaps 12.2 
to 12.5 may be joined together for example by glueing. 
In FIGS. 2a to 2c, the procedure has been illustrated for positioning blank 
1 with respect to the mandrel, when it is desired to apply board 3 against 
the corresponding lower face of mandrel 19. In these figures, it has been 
assumed that mandrel 19 was formed on bars 22 (seen in section), parallel 
and with rectangular sections, defining virtual bearing faces 23 to 26, 
respectively for panels 2 to 5, as well as folding edges 27 to 30 
corresponding respectively to the fold-lines 6, 7, 8 and 10. 
A blank 1 is brought in the vicinity of mandrel 19, so that its panel 3 is 
disposed facing the bearing face 24. 
Although it is desirable for the lateral positioning of said board 3 with 
respect to face 24 to be as accurate as possible, it may happen that a 
lateral shift 1 appears between panel 3 and said bearing face 24. To avoid 
untimely folding of blank 1, outside the fold-lines 6 and 7, during 
folding of panels 2 and 4, before folding said panels 2 and 4, panel 3 is 
moved away from the bearing face 24 by a distance d (see FIG. 2a). Then, 
during folding of said panels 2 and 4, panel 3 is brought close to the 
bearing face 24 by means of a plate 31, preferably exactly superimposable 
on said bearing face 24. Thus, while panel 3 is brought close to face 24, 
panels 2 and 4 bear against the mandrel 19 (see FIG. 2b) which generates a 
guiding effect and positions panel 3 exactly with respect to the bearing 
face 24. When plate 31 presses panel 3 against the bearing face 24, the 
fold-lines 6 and 7 are exactly superimposed on the folding edges 27 and 28 
so that, after final folding of flaps 2 and 4, respectively against the 
bearing faces 23 and 25, the fold-lines 8 and 10 are also exactly 
superimposed on the folding edges 29 and 30 (see FIG. 2c). 
The machine of the present invention, shown in FIGS. 3 to 8, comprises a 
frame 32 with respect to which are disposed a station 33 for supplying 
blanks, a station 34 for shaping said blanks about said mandrel 19 and a 
station 35 for removing the finished cases 20. Between the supply station 
33 and the shaping station 34 is disposed a horizontal table 36, provided 
with longitudinal slits 37 through which drive fingers 38 may pass. 
The supply station 33 comprises a magazine 39 containing a stack of blanks 
1, as well as means 40 for taking the upper blank 1, e.g. by suction, from 
said stack of blanks. Said taking means 40 are movable under the action of 
drive means 41 for successively taking the blanks 1 from magazine 39 and 
depositing them on table 36, upstream of the shaping station 34. Then the 
drive fingers 38, driven by a drive means 42, cause blank 1 thus taken and 
placed to slide over table 36 so as to bring it under the mandrel 19 of 
the shaping station 34. 
During transfer to the shaping station 34, blank 1 meets glue applicators 
43, 44 and 45, fixed to frame 32, and depositing respectively the lines of 
adhesive 16, 17 and 18. 
Thus, because of the drive fingers 38 and the glue applicators 43 to 45, 
blank 1 is disposed, already glued, under mandrel 19 in the position shown 
in FIG. 2a, above the pressure plate 31, driven by a jack 46. 
To fold panels 2 and 4, the shaping station 34 comprises the mechanism 47, 
shown in FIGS. 3, 4, 7 and 8. This mechanism 47 comprises a mobile 
assembly 48 which can be raised or lowered by means of a jack 49, bearing 
on frame 32. 
The mobile assembly 48 comprises two stops 50 and 51, capable of folding 
panel 2 and 4, respectively against the bearing faces 23 and 25 of mandrel 
19 (see also FIG. 2b) when the mobile assembly 48 is brought close to 
mandrel 19. 
In addition, said mobile assembly 48 comprises hinged arms 52 and 53 for 
folding panel 5 and tongue 9 respectively against the face 26 of mandrel 
19 after panels 2 and 4 have been folded between the bearing faces 23 and 
25. For example, arm 52 is driven by a jack 54 whereas arm 53 is actuated 
by a linkage 55, connected to frame 32. 
Inside mandrel 19 is disposed a transverse plate 56, serving as end face to 
said mandrel 19 and driven by a jack 57. 
Actuators 58 and 59, such as jacks for example, may fold flaps 11.2 and 
11.4 respectively against plate 56. 
After action of stops 50 and 51, arms 52 and 53 and actuators 58 and 59, 
the blank is in the state shown in FIG. 1c. 
At this time, in order to improve squaring of shaped blank 1 before final 
glueing, a longitudinal pressure may be exerted thereon, by means of jacks 
60 pressing it in the direction of actuators 58 and 59 bearing on the free 
edge of flaps 12.2, 12.4 and 12.5. 
After squaring, panel 5 is applied against the bearing face 26 by an arm 61 
swinging under the action of a jack 69. Panel 5 is then joined to tongue 9 
by means of the line of adhesive 16. 
Finally, jacks 62 and 63, possibly via pivoting plates 64 and 65, apply 
flaps 11.3 and 11.5 against flaps 11.2 and 11.4, previously folded against 
plate 56. Thus, said flaps 11.2 to 11.5 are joined together by means of 
the lines of adhesive 17 and 18, to form bottom 21. The case is then as 
shown in FIG. 1d. 
The removal station 35 comprises two staircase conveyors 67 and 68, so that 
when case 20 is discharged from the mandrel 19 by action of jack 57, it is 
tipped from conveyor 67 to conveyor 68 and is discharged thereby, on which 
it rests on its bottom 21. 
A cabinet 70 contains the means for controlling and synchronizing the 
different members of the above defined machine.