EP2663517A1

EP2663517A1 - Device for bending a thin sheet

Info

Publication number: EP2663517A1
Application number: EP12704291.9A
Authority: EP
Inventors: Nicolas PERDRIAU; Patrick RUBINSTEIN
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-01-13
Filing date: 2012-01-06
Publication date: 2013-11-20
Anticipated expiration: 2032-01-06
Also published as: WO2012095581A1; FR2970472A1; FR2970472B1; EP2663517B1

Abstract

The present invention relates to a device for bending a thin sheet, in particular a sheet of paper (33), according to equidistant parallel score lines made on said sheet, which extend transversely from one side of the sheet to the other. Said device is characterised in that it comprises: a frame capable of receiving a bending template which is at least the same size as the sheet (33) to be bent and which consists of a series of adjacent, transversal and identical parallel dihedrons (19) separated by a joining line; a translatably movable applicator means (35a, 35b, 35c) capable of consecutively applying a score line of the sheet (33) against a joining line of the bending template; a supporting means capable, during the actuation of the applicator means on a predetermined joining line, of keeping at least one score line applied against a joining line located upstream of said predetermined joining line.

Description

Folding device for a thin sheet

The present invention relates to a device and a method for producing, from a thin sheet, in particular a sheet of paper, comprising a series of parallel grooves, a folding along each of said grooves so as to form on one side to the other of the sheet a series of parallel and identical dihedra.

The present invention is particularly interesting in the field of display and in particular in the presentation of so-called composite photos. Indeed, display devices are known that consist of a plurality of adjacent and parallel dihedrums, the two faces of which are respectively coated with successive and alternating bands belonging to two different images or drawings so that, from an angle of observation given, an observer can see only one of these images and that, under another given angle of observation, he can see only the other image.

It is known that one of the difficulties of producing such an image presentation device is the introduction of the different bands on the respective faces of these dihedra, whether these images are printed directly on the faces of the latter or glued. on these, insofar as the precise positioning of the different bands plays a key role in the quality of the result obtained.

It has been proposed in US Pat. No. 5,598,650 to produce on the same sheet the different strips constituting the composite photograph that it is desired to display. Once this is done it is necessary to fold this composite photo following each of the lines of separation. A condition for obtaining a good image is that the angle of the fold is absolutely sharp and it has been proposed for this purpose to make grooves along the axis of the fold to promote the latter.

Such grooves must therefore be made accurately, which requires that they are both strictly parallel and the same width as that of printing, and strictly positioned relative to the latter.

It is known, with the existing printing material, to produce extremely precise alternating strips of photographs. It is also known to perform the grooving of these different bands in a sufficiently precise manner to obtain an absolute coincidence between the line of separation of two successive images and the folding groove.

It is still necessary that each fold line is formed rigorously at the location of a groove without any offset occurs during the folding itself.

The difficulty is all the greater as the size of the images, and consequently the number of grooves, is important. It is understood that, under these conditions, a small coincidence error between a groove and a fold line at the beginning of folding is translated at the end of it by a significant error due to the accumulation of errors.

The present invention aims to provide a device for folding in the form of a series of adjacent dihedrals the various printed and grooved strips so that the fold lines coincide precisely with the grooves previously made, and this in photographs large composites.

The present invention thus relates to a device for folding a thin sheet, in particular a sheet of paper, according to parallel and equidistant grooving lines formed thereon and which extend transversely across the sheet, characterized in that it comprises:

a frame adapted to receive a folding template of dimensions at least equal to those of the sheet to be folded and which is formed of a succession of parallel transverse and identical parallel dihedrals separated by a connecting line,

applicator means movable in translation capable of successively applying a grooving line of the sheet against a junction line of the folding jig,

- Holding means adapted, during actuation of the applicator means on a given junction line, to maintain applied at least one grooving line against a junction line located upstream of said determined junction line.

Moreover, the holding means may be such that, at any time during the folding operation of the sheet, at least one grooving line is maintained applied against a junction line located upstream of said determined junction line.

Preferably, said upstream junction line will be adjacent to the determined junction line.

According to the invention the applicator means will preferably consist of ^mobile vertically and transverse blades capable of penetrating into the inter-dihedral volume so that their summit may come to bear on the connecting line. These blades may comprise two active faces forming an angle slightly smaller than that formed by the faces of the dihedral between which they come to apply the sheet of paper.

In one embodiment of the invention the blades will be arranged on a gantry able to move, under the action of displacement means in the longitudinal direction of the folding jig. These displacement means will consist of stepper motors controlled by a control logic for moving the gantry according to equal movement steps.

Preferably, the displacement step will be equal to the distance separating two consecutive edges of the dihedrons forming the folding jig.

In order to maintain the folded parts of the sheet on the folding template, the dihedral forming it will be traversed by channels connected to suction means. Furthermore, the surface of the folding jig may be divided into several zones, each of these zones being connected to the suction means and a solenoid valve controlled by the control logic, may be interposed between each zone and the suction means.

An impervious fabric can be placed on the folding template, downstream of the applicator means and holding means. The device according to the invention may comprise means capable of winding said fabric as the applicator means and the holding means move.

According to the invention, at least one of the blades may be provided with actuating means capable of enabling it to move horizontally.

In addition, at least one of the blades may be provided with an advance. Preferably the blade located downstream of the blade provided with an advance will have, in front of it, a housing adapted to receive said advance.

In a preferred embodiment of the folding device according to the invention, the latter will have three blades, namely an upstream blade, a downstream blade and a median blade. The upstream blade will have advances at least its ends. The downstream and median blades may be provided with actuating means capable of enabling them to move horizontally.

In this embodiment of the invention the realization of a new fold will be provided by the vertical displacement of the downstream blade.

The present invention also relates to a method of folding on a template of a thin sheet, in particular a sheet of paper, according to parallel and equidistant grooving lines made sure thereof and which extend transversely from one side to the other of the sheet, this folding template being formed of a succession of parallel and identical parallel transversal dihedrals separated by a connecting line, characterized in that it comprises the steps of:

- successively applying a grooving line of the sheet against a given junction line (19b) of the folding jig,

during said application, maintaining at least one marking line against a junction line situated upstream of said determined junction line.

According to this method vertically movable blades will be used to apply the grooving lines of the sheet against the junction lines of the folding template.

Three blades will preferably be used, namely an upstream blade, a downstream blade and a median blade.

A new fold will preferably be provided by the vertical displacement of the downstream blade, at least the median blade being lowered during this movement so as to apply a previously formed fold against the folding jig during this movement. Once the fold realized, the upstream blade will be brought close to the median blade, so that advances of these come to take place in corresponding housing of the median blade, at least one of the downstream or middle blades being lowered during this movement, so as to keep applied the new fold formed and the preceding fold against the folding template.

The downstream and median blades will then be advanced by a value equal to the spacing of two consecutive vertices of the dihedrons forming the folding jig and the median blade will be lowered in the fold formed last, the upstream blade and its advances remaining lowered during this period. moving in the previous folds.

An embodiment of the present invention will be described hereinafter by way of nonlimiting example, with reference to the appended drawing in which:

FIG. 1 is a diagrammatic view along the width of a folding device according to the invention,

FIG. 2 is a schematic view along the length of the folding device represented in FIG. 1,

FIG. 3 is a partial sectional detail view of the gantry sliding means used in the folding device according to the invention,

FIG. 4 is a partial view of the folding blades of the device represented in FIG. 2,

FIG. 5 is a diagrammatic view of sectional details of the blades providing the folding and which are intended to cooperate with a folding jig,

FIG. 6 is a sectional detail view of the suction means designed to hold the already folded sheet portion on the folding template,

FIG. 7 is a side view along the length of the table, showing means for masking the unused dihedrons of the folding jig,

FIG. 8 is a partial plan view of a sheet of printed and grooved paper, which is to be folded, FIG. 9 is an enlarged schematic sectional view of a folding jig receiving a sheet and folding blades,

FIG. 10 is a detail view in perspective of the actuating jacks of the folding blades,

FIGS. 11 to 13 are perspective detail views of the jacks of FIG. 10 which are respectively equipped with a blade, two blades and three folding blades,

FIGS. 14a to 14c are cross-sectional views of the ends of the folding blades,

FIGS. 15 to 18c are schematic views illustrating the respective movements of the blades during a folding cycle.

As shown in the schematic figures 1 to 3 the folding device 1 according to the invention comprises a frame consisting of a rectangular table 3 resting on the ground by four feet 5. The table 3 comprises on its two opposite longitudinal edges backstage 7 on which is slidably mounted a gantry 8. The latter is constituted on each of the longitudinal sides of the table 3 of a pair of sliders 9 which cooperate with the slides 7 and which receive vertical uprights 11 which support a transverse upright 13.

The gantry 8 comprises advance means, not shown in the drawing, which consist in particular of stepping motors whose advance is controlled and controlled by a control logic 15 so that the gantry can move from one to the other. end to end of table 3.

The surface of the latter receives a rectangular folding template 17, made for example in synthetic material, and which is constituted, as shown in FIG. 5, of dihedrons 19 whose angles at the apex are close to 90 ° and which extend along the entire transverse dimension of the table 3, ie perpendicular to the direction of movement D of the gantry 8.

As shown in Figure 6, the base of the folding template 17 is hollowed out of a chamber 21 which is in communication with the outside by channels 23 which pass through each dihedron 19 to open on one side thereof. These channels are distributed periodically over the entire length of each dihedron 19. The chamber 21 is connected by connection means 25 and a pipe 27 to a suction pump 29.

Preferably, as shown in Figures 1 and 2, the base of the folding jig 17 is divided into several sectors which are each fed by a manifold 31 which is itself fed by a pipe 32 connected to the vacuum pump 29 with interposition of controllable solenoid valves, 32a, 32b, 32c, 32d, 32e respectively, by the control logic 15. Such an arrangement makes it possible to control the sectors in which it is desired to evacuate, and this as a function of the position of the gantry 8. thus achieves a power saving of the vacuum pump which makes it possible to work with a lower power pump.

In another variant of the invention which is shown in FIG. 7, an air-impervious fabric 18 is placed on the folding template 17 which is wound on a transverse roll 20 which is secured to the gantry 8 by an upright 22. , so that when the latter moves in the direction D during the folding operation, the fabric 18 is wound on the roll 20 so as to clear the dihedral template which will be used for folding. Such an embodiment makes it possible to mask the dihedrons 19 of the template 17 that have not yet been used, so as to reduce the suction energy required for the plating of the part of the folded sheet against the template. It is thus possible, thanks to such an arrangement, to use, as shown in FIG. 7, only a single collector 31 and a suction pump of reduced power.

According to the invention there is a paper sheet which is coated with a composite image. An image consisting of several basic images, for example a pair of images, as described below, which is printed on a flexible support such as preferably a paper sheet such a composite image, as shown in FIG. 8, two graphic representations are initially available, for example photographs, which are respectively divided into a first series a, b, c,. second series a ', b', c ', ...' 'of parallel strips of the same width, of the order for example of 10 mm, which are assembled together so that the first band has the first series and the first band a_ of the second series are arranged adjacently. And this is done step by step alternately so as to successively find the bands a, a ', b, b', c, c '... j j' so as to form a new composite photograph.

To ensure the folding of the sheet of paper 33 which is printed and grooved on each line of separation of two adjacent photos, it is placed on the folding template 17 and is blocked so that the first groove coincides with the first edge 19a of the folding template 17. According to the invention and as shown in FIG. 6, the sheet is applied to the folding template so that successive grooves can be found respectively applied against an edge 19a and against the bottom 19b between the dihedrals 19, hereinafter referred to as a connecting line. Once this application has been made, the sheet of paper 33 remains held against the dihedrons 19 of the folding template 17 under the effect of the suction effected by the vacuum pump 29 via the suction channels 23 provided therein.

As shown diagrammatically in FIG. 9, the application of the sheet 33 on the folding template 17 is carried out by means of a set of three blades, namely an upstream blade 35a, a median blade 35b, and a downstream blade. 35c which extend over the entire transverse dimension of the table 3 and which perform a vertical movement ν_ ^ as explained below, under the action of respective pneumatic cylinders 37a, 37b, 37c, as shown in FIG. 10, whose movements are controlled by the control logic 15. The median blades 35b and 35c downstream can also perform a horizontal and longitudinal displacement h relative to the gantry 8. For this purpose the respective cylinders 37b and 37c which support them are mounted on a horizontal jack 40 able to perform such a displacement under the control of the control logic 15 as shown in the partial figure 4.

As shown in FIG. 5, the blades 35a, 35b, 35c have an apex angle A which is slightly smaller than the angle of the dihedrons 19 and which is preferably of the order of 86 ° so that during their movement of vertical movement v their active end can bear on the connecting line 19b.

In order to facilitate movement when the width of the folding jig 17 is large, it is possible, as shown in FIG. 1, to use several series of blades, in particular three series which are arranged in the transverse extension of one another and whose movement is synchronized by the control logic 15.

FIG. 10 shows a support plate 38 of the cylinders 37a, 37b, 37c which are intended to support the blades 35a, 35b, 35c and FIGS. 11 to 13 show the same support plate on which are respectively mounted a blade 35a, two blades 35a and 35b and the three blades 35a, 35b, and 35c.

As shown in ^"Figures 11 and 14a, the first blade, or upstream blade 35a, comprises at each of its ends and in the middle an advanced 35 'has the base of which reproduces that of the ^blade' proper.

The second blade, or median blade 35b, as shown in Figures 12 and 14b, is provided at its ends and at its center with a recess 39 which is intended to receive the advances 35 'of the blade 35a, which allows the latter to bear against the blade 35b as shown in Figure 12.

The third blade, or downstream blade 35c, which is shown in Figures 13 and 14c is of conventional type.

The movement which is applied to the various blades as well as to the gantry 8 which supports them during a complete cycle of the folding operation and which can be broken down into three main phases will be described below.

In the first phase, starting from a position, shown in Figure 15, wherein the three blades 35a, 35b, 35c are lowered and are applied against each other. In this position the advances 35 'of the upstream blade 35a are housed in the associated recesses 39 of the median blade 35b. The logic 15 then controls the following movements:

the median blades 35b and downstream 35c are raised, and the tear 35a remains depressed (FIG. 16a) the median blades 35b and downstream 35c are displaced forwards by the jack 40 by a distance h equal to a spacing e between two vertices 19a of the dihedrons 19 of the folding jig 17, and the blade 35a remains depressed (FIG. 16b) ,

the median blade 35b is lowered in the last fold made during the previous cycle (FIG. 14c),

During the second phase, the downstream blade 35c is lowered onto the sheet 33, which then forms a new fold. It will be noted that, during the formation of this new fold (FIG. 17), the three folds disposed upstream of it are firmly held by the median blade 35b located upstream of the working blade 35c, and by the upstream blade 35a and its advance 35 'b, which prevents slipping of the sheet 33 during this operation. Moreover, in particular because the angle at the apex A of the downstream blade 35c is smaller than the angle at the apex of the dihedrons, the apex of this blade can come into contact with the junction line 19b and thus bring the grooving line of the sheet 33 against this line of junction. Such a device thus makes it possible, at each formation of a fold, to refocus the position of a grooving line of the sheet with respect to a junction line of the folding jig.

During the third phase, the upstream blade 35a is raised (FIG. 18a) and the gantry 8 is advanced by a value h corresponding to the distance e existing between two consecutive vertices of the dihedrons 19 of the folding jig 17, and this all by retracting the jack 40 so that the median blades 35b and downstream 35c remain stationary relative to the sheet 33 so that they continue to hold the last two folds of the paper sheet 33 applied to the folding template 17. then finds himself in the starting position. It will be noted that, during the formation of a fold by the downstream blade 35c (FIG. 17) during the second phase, the already folded portion of the sheet is held on the one hand by the median blade 35b and on the other hand on the other hand, by the upstream blade 35a and its advance 35 'a, which ensures an effective maintenance on the folding jig 17.

It will also be noted that during the entire folding process during which the blades lift and move at any time, the folded portion of the sheet is held against the folding template by at least one blade. This arrangement also helps prevent slippage of the sheet relative to the template throughout the process.

Claims

1. - A device for folding a thin sheet, in particular a sheet of paper (33), according to parallel and equidistant grooving lines formed thereon and which extend transversely from one side to the other of the sheet, characterized in that it comprises:

- A frame (3) adapted to receive a folding jig (17) of dimensions at least equal to those of the sheet (33) to be folded and which is formed of a succession of parallel dihedrals (19) adjacent transverse and identical identical by a connecting line (19b),

translational mobile applicator means (35a, 35b, 35c) adapted to sequentially apply a grooving line of the sheet (33) against a junction line (19b) of the folding jig (17),

- Keeping means adapted, during 1 actuation of the applicator means on a given junction line, to maintain applied at least one grooving line against a junction line (19b) located upstream of said determined junction line.

2. - Folding device according to claim 1 characterized in that the holding means are such that at any time during the folding operation of the sheet, at least one grooving line is maintained applied against a junction line located upstream of said determined junction line.

3. - Folding device according to one of claims 1 or 2 characterized in that said upstream junction line is adjacent to the determined junction line.

4. - Folding device according to one of claims 1 to 3 characterized in that the means Applicators consist of transverse blades (35a, 35b, 35c) vertically movable and able to penetrate into the interdidihedral volume (19) so that their top can bear on the junction line (19b).

5. - Folding device according to claim 4 characterized in that the blades (35a, 35b, 35c) comprise two active faces forming an angle (A) slightly smaller than that formed by the faces of the dihedron (19) between which they come apply the sheet of paper (33).

6. - Folding device ^ according to claim 5 characterized in that the corners at the top of the dihedrons (19) forming the folding jig (17) are of the order of 90 ° and the angles at the apex (A) of the faces active blades (35a, 35b, 35c) are of the order of 86 °.

7. - Folding device according to one of claims 4 to 6 characterized in that the blades (35a, 35b, 35c) are arranged on a gantry (8) able to move, under the action of moving means, in the longitudinal direction of the folding jig (17).

8. - Folding device according to claim 7 characterized in that the displacement means consist of stepper motors controlled by a control logic (15), so as to move the gantry (8) in equal steps of displacement .

9. - Folding device according to claim 8 characterized in that the displacement step is equal to the distance (e) between two edges (19a) consecutive dihedral (19) forming the folding template (17).

10. - Folding device according to one of the preceding claims characterized in that the dihedrals (19) forming the folding jig (17) are traversed by channels (23) connected to suction means (29).

11. - Folding device according to claim 10 characterized in that the surface of the folding jig (17) is divided into several zones, each of these areas being connected to the suction means (29).

12. - Folding device according to claim 11 characterized in that a solenoid valve (32a, 32b, 32c, 32d) controlled by the control logic (15) is interposed between each zone and the suction means (29). .

13. - Folding device according to one of claims 4 to 12 characterized in that at least one of the blades (35a, 35b, 35c) is provided with actuating means (40) adapted to allow it a movement of horizontal movement (h).

14. - Folding device according to one of claims 1 to 9 characterized in that it comprises an impervious fabric (18) which is arranged on the folding template (17) downstream of the applicator means and holding means.

15. - Folding device according to claim 14 characterized in that it comprises means adapted to wind said web (18) as the displacement of the applicator means and holding means.

16. - Folding device according to one of claims 3 to 15 characterized in that at least one of the blades (35a) is provided with a projection (35 'a).

17. - Folding device according to claim 16 characterized in that the blade (35b) located downstream of the blade (35a) provided with an advance (35 'a) has, in front of the latter, a housing ( 39) adapted to receive said advance (35 'a).

18. - Folding device according to one of claims 3 to 17 characterized in that it has three blades, namely an upstream blade (35a), a downstream blade (35c) and a median blade (35b).

19. - Folding device according to claim 18 characterized in that the upstream blade (35a) has advances (35 ') at least at its ends.

20. - Folding device according to one of claims 18 or 19 characterized in that the downstream blades (35c) and median (35b) are provided with actuating means (40) capable of allowing them to move horizontally ( h).

21. - Device for folding according to any one of claims 18 to 20 characterized in that the realization of a new fold is provided by ^'the vertical displacement (v) of the downstream blade (35c).

22. - A method of folding on a template (17) of a thin sheet, in particular a sheet of paper (33), according to parallel and equidistant grooving lines formed thereon and which extend transversely on one side to the other of the sheet (33), this folding template (17) being formed of a succession of parallel and identical parallel transverse dihedrals (19) separated by a connecting line (19b), characterized in that comprises the steps of:

- successively applying a grooving line of the sheet (33) against a given junction line (19b) of the folding jig (17),

23. - Folding method according to claim 22 characterized in that vertically movable blades (35a, 35b, 35c) are used to apply the grooving lines of the sheet (33) against the junction lines of the folding jig. (17).

24. - Folding method according to one of claims 22 or 23 characterized in that three blades are used, namely an upstream blade (35a), a downstream blade (35c) and a median blade (35b).

25. - Folding method according to one of claims 22 to 24 characterized in that a new fold is provided by the vertical displacement (v) of the downstream blade (35c), at least the median blade being lowered during this movement of to apply a previously formed fold against the folding template (17) during this movement.

26. - Folding method according to claim 25 characterized in that once the fold realized, the blade upstream

(35a) is brought near the median blade (35b), so that advances (35 'a) thereof come to take place in corresponding housing (39) of the median blade

(35b), the downstream blade (35c) being lowered during this movement so as to maintain applied the new fold formed against the folding jig (17).

27. - Folding method according to claim 26 characterized in that the downstream blades (35c) and median (35b) are then advanced by a value (e) equal to the spacing of two consecutive vertices dihedral (19) forming the folding jig (17) and the median blade (35b) is lowered in the fold recently formed, the upstream blade and its advances remaining lowered during this movement in the previous folds.