EP3363916A1 - Device for flattening a flexible membrane - Google Patents

Abstract

- Flattening device of flexible membrane.
The invention relates to a flattening device (13) for a flexible membrane (12), of the animal skin component type, comprising:
at least two elements (2a, 2b) each designed to move in cyclic translation along a respective trajectory describing a respective closed curve, said respective displacements in cyclic translation of said two elements (2a, 2b) being at least partly symmetrical so that said two elements (2a, 2b) come simultaneously and intermittently press said membrane (12) against a support (1) while moving away from each other to locally stretch said membrane (12).

The invention also relates to a method for flattening the associated flexible membrane.

Description

The present invention relates to the general field of treatment of flexible membranes, and more particularly membranes of the animal skin type. The present invention thus relates in particular to the general sector of the industrial tannery.

The present invention relates more particularly to a device and a method for flattening flexible membrane, of the kind piece of animal skin.

It is known, in the field of industrial tanning, to resort to an operation of slitting an animal skin (or "leather") using machines (called "slitters") comprising an endless blade preceding rotating rollers between which passes the skin. Slitting consists in dividing said skin into several layers in its thickness in order to separate the flower and the crust. The introduction of said skin into a slitter first requires a flattening of said skin in order to obtain sufficient cutting accuracy, and therefore a quality of skin split evenly and satisfactorily.

It is also known, for carrying out an operation for dyeing an animal skin, to use rotating roller machines between which the skin passes. Such an operation also requires a prior flattening of said skin, in order to obtain a regular and satisfactory tinted skin quality.

It is known, for introducing skins into a slitter, to use upstream of said slitter a device for automated introduction of skins comprising several conveyor belts, which will cause said skins to enter said slitter, that is, that is to say between two rotary rollers of said slitter, allowing operators, who are no longer in contact with said slitter, to work in a secure manner. In addition, the use of this introduction device makes it possible to obtain a better repeatability of the slitting operations, resulting in a constant and controllable end product quality. Finally, the use of this introduction device makes it possible to obtain a satisfactory quality of finished product by limiting the pressure necessary to exert on the pieces of skin in the slitter (that is to say the pressure exerted by rotating rollers of the slitter), reducing the risk of appear marks on the "flower" of said skins, which is the noble part, that is to say the most sought.

However, it turns out that this introduction device, if it gives overall satisfaction, does not guarantee a perfectly even and sufficient flattening of the skins to systematically avoid any source fold fault. Indeed, said skins, before their introduction into said introduction device, are of uneven thickness, wet, wrinkled and slippery, and although their general condition is improved by said introduction system, it does not allow to avoid any crease just before their introduction between the rotary rollers of said slitter.

It is also known, for flattening a flexible skin before an industrial tannery operation, to position two treadmills placed above said skin, said mats moving in respective opposite rotary movements to spread said skin using a plurality of flaps secured to each of said mats, said flaps contacting said skin to stretch.

However, this device is bulky, of complex and expensive construction, and does not allow to obtain a satisfactory flattening of the skins especially locally, in a limited space, as at the entrance of the rotary rollers of an industrial tannery machine such as a slitter or a machine for finishing type dyeing. Finally, such a configuration increases the risk of damaging the skins, said flaps "scraping" transversely said skins on a large surface of the latter.

The objects assigned to the invention are therefore intended to remedy the various disadvantages mentioned above and to propose a new device for flattening flexible membrane which, while being robust, inexpensive and of limited space, is extremely effective and preserves the integrity of said membrane.

Another object assigned to the invention is to provide a new flattening device particularly reliable and simple structure.

Another object assigned to the invention is to propose a new flattening device whose implementation within an industrial tannery production line is easy, fast and cheap.

Another object assigned to the invention is to propose a new flattening device capable of ensuring flattening even in small spaces.

Another object assigned to the invention is to propose a new device for flattening flexible membrane which can easily adapt to different types of flexible membranes.

Another object assigned to the invention is to propose a new flattening device particularly suitable for soft skins of animal skin type.

Another object assigned to the invention is to propose a new flattening device which makes it possible to remove the folds of a flexible membrane irrespective of the orientation of said folds.

Another object assigned to the invention is to provide a new flattening device that allows to lay a flexible membrane without degrading the surface.

Another object assigned to the invention is to provide a new flattening device that allows to stretch a flexible membrane without tearing.

Another object assigned to the invention is to propose a new flattening device which makes it possible to increase the profitability of an industrial tannery treatment.

The objects assigned to the invention are achieved by means of a device for flattening flexible membrane, of the animal skin component type, characterized in that it comprises at least two elements each designed to move in translation. cyclic according to a respective trajectory describing a respective closed curve, said respective displacements in cyclic translation of said two elements being at least partially symmetrical so that said two elements come simultaneously and intermittently press said membrane against a support while moving away from it one of the other to locally stretch said membrane.

The objects assigned to the invention are also achieved by means of a method for flattening flexible membranes, of the animal skin component type, characterized in that it comprises at least one primary stretching stage, in which which at least two elements each move in cyclic translation according to a respective trajectory describing a respective closed curve, said respective displacements in cyclic translation of said two elements being at least partially symmetrical so that said two elements come simultaneously and intermittently press said membrane against a support while moving away from each other to locally stretch said membrane.

• La Figure 1 illustre, selon une vue de côté, un exemple d'un dispositif de mise à plat conforme à l'invention et conçu pour la mise à plat de pièce de peaux animales, ledit dispositif étant en l'espèce associé à une refendeuse et à un système d'introduction de peaux dans ladite refendeuse.
• La Figure 2 illustre, selon une vue de face, le dispositif de mise à plat de la figure 1 pris seul.
• La Figure 3 illustre, selon une vue de face, d'un détail agrandi du dispositif de la figure 2.
• La Figure 4 illustre, selon une vue en coupe BB', le dispositif de la figure 2.
• Les Figures 5, 6 et 7 illustrent respectivement, selon des vues de face, différentes configurations successives du dispositif des figures 1 à 4.

Other features and advantages of the invention will emerge and will appear in more detail on reading the description given below, with reference to the accompanying drawings, given solely by way of illustrative and non-limiting examples, in which:

• The Figure 1 illustrates, in a side view, an example of a flattening device according to the invention and designed for flattening piece of animal skins, said device being in this case associated with a slitter and a skin introduction system in said slitter.
• The Figure 2 illustrates, according to a front view, the flattening device of the figure 1 taken alone.
• The Figure 3 illustrates, according to a front view, an enlarged detail of the device of the figure 2 .
• The Figure 4 illustrates, in a sectional view BB ', the device of the figure 2 .
• The Figures 5, 6 and 7 respectively illustrate, according to front views, different successive configurations of the device of the Figures 1 to 4 .

The present invention relates to a flattening device 13 of flexible membrane 12, of the kind piece of animal skin. In particular, said device 13 makes it possible to reduce or even eliminate all the folds of a flexible membrane 12, in particular by locally stretching said membrane 12.

Said flattening device 13 is in particular intended to be integrated within an industrial tannery unit to improve the quality of treatment of said flexible membrane 12, by putting said membrane flat before said treatment. This is for example a slitting operation carried out by a slitter, or a dyeing operation performed by a suitable machine. More particularly, said flattening device 13 is intended to be incorporated in a flexible membrane introduction system which drives said membrane, in a direction of flow, to an industrial tannery machine exerting said treatment, for example a slitter. These uses, and the embodiments described below, are given by way of non-limiting examples of the scope of the present invention.

Said flexible membrane 12 is of the animal skin kind, and is preferably a natural animal leather. It can also be a membrane with similar characteristics and therefore likely to be flattened, for example before treatment, including an industrial tanning treatment. Thus, said flexible membrane 12 is for example a synthetic leather, a woven fabric or a nonwoven fabric. Said membrane 12 is said to be flexible, that is to say that it is capable of forming folds, for example during transport or handling, and that said folds can be eliminated without tearing said membrane 12 for example by stretching it. Said flexible membrane 12 is very preferably of substantially flat general shape, although it may have irregularities, and has two opposite faces and a thickness. A fold of said flexible membrane corresponds, for example, to a local doubling or tripling of its thickness, or to a relief or a bump on one of said two faces (corresponding to a concavity or a depression on the other of said two faces). faces).

Said flattening device 13 comprises at least two elements 2a, 2b each designed to move in cyclic translation according to a respective trajectory describing a respective closed curve. In other words, said two elements 2a, 2b each perform a respective displacement during which, at any moment, each keeps the same orientation in space. Each of said two respective displacements in translation is cyclic, that is to say, repeatedly in time, according to a respective trajectory describing a respective continuous curve folding on itself. The respective curve can be for example of shape polygonal, curvilinear or elliptical. It advantageously describes an ellipse, preferably a circle (it may be considered in particular that a circle represents a particular case of ellipse). Each of said two displacements in cyclic translation preferably has a respective period at the end of which it repeats, preferably identically, said two respective periods being advantageously substantially close, preferably equal as illustrated.

Preferably, said trajectory of each of said two elements 2a, 2b is substantially elliptical.

Advantageously, and as illustrated in the figures, the respective trajectory of each of said two elements 2a, 2b is substantially circular, said two elements 2a, 2b thus preferably moving each in respective circular translation (that is to say according to a displacement respective circular, or in a path where the elements 2a, 2b each perform a respective circular trajectory), in the manner of a nacelle in a ferris wheel carnival (the same analogy adapted to the two elements 2a, 2b together would give two respective nacelles of two different fairground wheels rotating in respective opposite directions, hourly and counterclockwise). Alternatively, said trajectory may be substantially oval, or of rectangular, square, triangular shape, of the shape of other regular polygons or irregular polygons, or of the shape of other closed curvilinear curves.

Preferably, each of said two elements 2a, 2b has a respective substantially straight elongate shape which extends longitudinally along a (same) main extension direction C.

More preferably, and as shown in the figures, said flattening device 13 comprises two plate-like pieces 9a, 9b (that is, each piece 2a, 2b advantageously forms a respective plate), each of said two elements 2a, 2b being formed by a respective edge of one of said substantially plate-shaped pieces 9a, 9b (respectively).

Preferably, each of said two elements 2a, 2b is in one piece, that is to say integrally, with a different (that is to say respective) of said two parts 9a, 9b. Alternatively, each of said two elements 2a, 2b is attached, that is to say added, glued or fixed, with a different (that is to say respective) of said two parts 9a, 9b.

Preferably, each of said two pieces 9a, 9b is in the form of a plate forming a quadrilateral, which is more preferably a rectangle or a square. Advantageously, said two edges respectively formed by said two elements 2a, 2b are the respective lower edges of said two parts 9a, 9b.

Advantageously, said two substantially plate-shaped pieces 9a, 9b are planar, i.e. each has a respective width, length and thickness, said respective thickness being much smaller than said length and width. respectively. For example, said respective thickness is less than one-tenth of said respective width and less than one-twelfth of said respective length.

Advantageously, said two edges are rounded, that is to say convex, to avoid degrading said flexible membrane 12 to its contact.

Preferably, and as illustrated in figures 2 , 3 , 5, 6 and 7 said two substantially plate-shaped pieces 9a, 9b extend substantially in the same plane P. In other words, the respective lengths and widths of said two pieces 9a, 9b extend in a same plane P which passes by said main extension direction C.

The figure 2 illustrates front of said flattening device 13 of flexible membrane 12 alone, said two elements 2a, 2b being arranged side by side.

According to the present invention, the respective displacements of said two elements 2a, 2b are at least partly symmetrical so that said two elements 2a, 2b come simultaneously and intermittently press said membrane 12 against a support 1 while moving away one on the other hand to locally stretch said membrane 12. In other words, said two elements 2a, 2b advantageously perform respective cyclic displacements which are symmetrical to each other during at least a portion of their respective cycle, and said two elements 2a, 2b are in contact with said membrane 12 to press against said support 1 for part or all of the duration of these respective symmetrical displacements. As represented in figure 3 and to Figures 5, 6, and 7 (Except support 1 and said flexible membrane 12 which is in fact below said two elements 2a, 2b, said support being below said membrane 12), said two elements 2a, 2b come into contact with said membrane 12 and then press it simultaneously against said support 1, then " slide " on the surface of the membrane 12 to stretch and remove the folds away from one another, before moving away from the latter and / or no longer exert pressure on it. Said two elements 2a, 2b are in contact and / or pressure of said membrane 12 substantially during the same time interval, and press said membrane 12 only intermittently, that is to say during a fraction of the period the respective cyclic translation displacement of each of said two elements 2a, 2b. Said membrane 12 is stretched locally, that is to say preferably on only a portion of its surface, even more preferably a portion (or two half-portions) substantially elongate (s) and / or rectilinear (s) (and or aligned) of said surface. Advantageously, said two elements 2a, 2b, during (at least a part) of their respective displacements in cyclic translation, locally press a portion (where they each each locally press a respective half-portion) substantially elongated surface of said membrane 12.

Preferably, said two elements 2a, 2b move in two respective directions opposite to each other.

Advantageously, and as represented at figure 2 said two elements 2a, 2b are arranged to stretch said membrane 12 in at least a first direction of stretch E.

Advantageously, and as represented at figure 2 said first stretching direction E is substantially parallel to said main extension direction C. Preferably, said elements 2a, 2b move away from each other in said main extension direction C and / or said first stretching direction E.

Preferably, and as shown in figures 2 , 3 , 5, 6 and 7 said two elements 2a, 2b are substantially identical and have respective displacements completely symmetrical. Said two elements 2a, 2b then advantageously press said membrane 12 against said support 1 for only part of their respective symmetrical displacements.

For example, at a time t of the cycle, and as represented at figure 5 said two elements 2a, 2b come closer to each other, without being in contact with said membrane 12 but approaching it. At a time following t + 1 of the cycle, as shown in FIG. figure 6 said two elements 2a 2b are in contact with said flexible membrane 12 (not shown here, but which is situated below said two elements 2a, 2b) and thus come to press it, that is to say to gently pinch it or more strongly, applying a small or large pressure, against said support 1 (not shown here, but which is located below said membrane 12). At a time following t + 2 of the cycle, as shown in FIG. figure 7 said two elements 2a 2b move away from each other, while applying a certain pressure on said membrane, thereby stretching it to remove the folds, said pressure decreasing as said two elements 2a , 2b continue to move away from each other to the point that they lose contact with said membrane 12, thus avoiding degradation thereof.

Said support 1 against which said two elements 2a, 2b come to press said membrane 12 can be of any type capable of supporting said flexible membrane 12. Preferably, it has a substantially flat surface, locally flat, concave, convex, or corresponding to the outer surface of a cylinder, the latter example being illustrated in particular in FIG. figure 1 .

Advantageously, said first stretching direction E is substantially perpendicular to a conveying direction H in which a driving means 4 moves said membrane 12 relative to a fixed frame 22 on which said support 1 is intended to be mounted.

Preferably, said frame 22 may be any type of structure preferably immobile with respect to the ground, in particular an industrial tannery machine. advantageously, said flattening device 13 of flexible membrane 12 is also mounted on said fixed frame 22.

Preferably, said conveying direction H is substantially perpendicular to said main extension direction C.

Said drive means 4 is advantageously designed to support said membrane 12 and to drive it along said conveying direction H. As illustrated in FIG. figure 1 , said flattening device 13 is advantageously integrated into an assembly further comprising a slitter 14 and a flexible membrane introduction system 15 introducing said membrane 12 to the inlet of said slitter 14. In other words, said introduction system 15 supplies said slitter 14 with a flexible membrane 12.

Preferably, and as in the example shown in FIG. figure 1 said frame 22 is constituted by a fixed part with respect to the ground of said introduction system 15. In the particular example illustrated in FIG. figure 1 , the flattening device 13 is thus mounted on a fixed portion relative to the ground of said introduction system 15, which is itself substantially fixed relative to the ground. Alternatively, said frame 22 may be constituted by said slitter 14 and in particular a fixed part thereof.

In the example shown in figure 1 and which is purely illustrative and nonlimiting, said slitter 14 is in particular provided with a slitting blade 16 for slitting said membrane 12, and two rollers 4 in the form of cylinders designed to pass said membrane 12 between them, resulting in this last in said conveying direction H, and exerting if necessary a pressure on said membrane 12. In this example, said rollers 4 constitute said drive means 4 of said membrane 12.

Said membrane introduction system 12 advantageously comprises at least one means 5 for conveying said membrane 12 to said slitter 14. Said conveying means 5 is for example a conveyor belt 5, or, as shown in FIG. figure 1 , two conveyor belts 5, which preferably face each other and between which said membrane 12 is conveyed towards said slitter 14.

According to the embodiment illustrated in figure 1 , said introduction system 15 conveys said flexible membrane 12 to said drive means 4 of said slitter 14, which will itself cause said membrane 12 to be slit, said slitting blade 16. The device of lying flat 13 is here positioned downstream of said introduction system 15 and upstream of said slitter 14, so as to lay said flexible membrane 12 at its exit from said conveying means 5 and just before passing through said drive means 4, which is, in the illustrated example, formed by said two rollers 4.

In the particular example shown in figure 1 a portion of one of said rollers, preferably a portion cut longitudinally in one of said rollers 4, preferably a roll positioned below the other, forms the support 1 against which said elements 2a, 2b press said membrane 12.

Alternatively, said conveying means 5 of said introduction system 15 may constitute, in a non-illustrated embodiment, said means for driving said membrane 12 in a conveying direction H perpendicular to said first direction of stretch E.

Preferably, said flattening device 13 of flexible membrane 12 comprises traction means 4 'of said membrane 12 in a traction direction T perpendicular to said main extension direction C of said two elements 2a, 2b, said means of traction 4 'cooperating with said elements 2a, 2b to stretch said membrane 12 in said traction direction T.

Advantageously, said traction direction T is parallel to said conveying direction H, and said traction means 4 'are formed by said drive means 4.

Preferably, when said two elements 2a, 2b are in contact with said flexible membrane 12 and exert a certain pressure on it, pressing or pinching it against said support 1, said membrane 12 is then also stretched, according to said conveying direction H, between said drive means 4, (preferably formed by said two rotary rollers 4), and said two members 2a, 2b (i.e. the place where said membrane 12 is pressed between said two elements 2a, 2b and said support 1). In other words, said membrane 2a, 2b is preferably laid flat along said conveying direction H and said first direction of stretching E, said conveying direction H and said first direction of stretching E being substantially perpendicular.

Preferably, said flexible membrane 12 has a length and a width, said width being for example smaller than said length. Preferably, said drive means 4 drives said membrane 12 in the direction of the length of said membrane 12.

• ils étirent localement ladite membrane 12 sur sa largueur (et de préférence sur toute sa largeur) selon ladite première direction d'étirement E,
• et ils étirent localement ladite membrane 12 en combinaison avec lesdits moyens de traction 4' selon une seconde direction d'étirement F sensiblement perpendiculaire à ladite première direction d'étirement E (et parallèle à ladite direction de traction T et à ladite direction de convoyage H), de préférence sur toute la surface de ladite membrane 12 située entre lesdits moyens de traction 4' (de préférence lesdits rouleaux rotatifs 4) et lesdits éléments 2a, 2b.

Advantageously, said elements 2a, 2b are arranged side by side in said plane P, positioned above said membrane 12, and overlie substantially the entire width of said flexible membrane 12. In this way, when said elements 2a, 2b come to the contact of said membrane 12, they advantageously produce two effects, which are preferably substantially concomitant (but which can alternatively be shifted in time):

• they locally stretch said membrane 12 on its width (and preferably over its entire width) in said first stretching direction E,
• and they locally stretch said membrane 12 in combination with said traction means 4 'in a second stretching direction F substantially perpendicular to said first stretching direction E (and parallel to said traction direction T and said conveying direction H ), preferably over the entire surface of said membrane 12 located between said traction means 4 '(preferably said rotary rollers 4) and said elements 2a, 2b.

The fact of well flattening said flexible membrane 12 allows in particular, in the present example, to obtain larger areas of slit membranes (a flexible membrane at the inlet of a slitter gives two membranes slit at the outlet of the slitter). This is particularly interesting from an economic point of view, particularly in the field of industrial tannery, since the flexible split membranes, and in particular the split animal skins, are bought by the piece and sold on the surface.

• un actionneur 11 qui est pourvu d'un arbre moteur 6 rotatif,
• une chaîne cinématique 7 reliant ledit arbre moteur 6 à au moins un premier 2a desdits deux éléments 2a, 2b pour convertir la rotation de l'arbre moteur 6 en un premier mouvement elliptique, de préférence circulaire, dudit premier élément 2a.

Preferably, and as illustrated in figures 1 , 3 and 4 said flattening device 13 of flexible membrane 12 further comprises:

• an actuator 11 which is provided with a rotary motor shaft 6,
• a kinematic chain 7 connecting said drive shaft 6 to at least a first 2a of said two elements 2a, 2b to convert the rotation of the drive shaft 6 into a first elliptical movement, preferably circular, of said first element 2a.

Preferably, said kinematic chain 7 converts the rotation of the motor shaft 6 into a circular movement of said first element 2a.

Preferably, and as represented at figures 2 , 3 , 5, 6, 7 , said flattening device 13 also comprises a first intermediate body 8a, a first 2a of said two elements 2a, 2b being freely pivotally connected to said first intermediate body 8a along a first axis of rotation A.

Advantageously, and as illustrated in figure 4 said driving shaft 6 is connected to said first intermediate body 8a to rotate it along a second axis of rotation A 'which is parallel and offset from said first axis of rotation A.

More preferably, said first intermediate body 8a is substantially flat in shape having a first geometric center, and at least one of said first A and second A 'axes of rotation is offset from said first geometric center. Preferably, the first A and second A 'axes of rotation are both offset from said first geometric center, and are offset with respect to each other.

Preferably, said first intermediate body 8a is of circular, oval or polygonal shape such as a square, a triangle or a rectangle.

For example, as shown in figure 4 , the actuator 11 is an electric geared motor offset from said elements 2a, 2b, for example above them, and provided with a motor output shaft 6, itself connected to a first toothed wheel 17 having even axis around which is positioned a transmission belt 18.

Said transmission belt 18 is also positioned around a second toothed wheel 19, so as to transmit to it the rotational movement of said first toothed wheel 17. Preferably, said first toothed wheel 17 has a greater diameter than said motor shaft 6, and said second toothed wheel 19 has a larger diameter to said drive shaft 6 and less than said first toothed wheel 17. Said second toothed wheel 19 sees its hub extended by an output shaft 20 which itself is connected to said first intermediate body 8a along an axis parallel to said second axis of rotation A '. In this way, a rotational movement of said second toothed wheel 19 causes a rotational movement of its output shaft 20, which itself causes a rotational movement of said first intermediate body 8a, the latter then driving said first element 2a in an elliptical translation movement, or even more preferably in circular translation, in the manner of a nacelle in a large fairground wheel, said first intermediate body 8a playing the role of the large wheel in rotation. Said kinematic chain 7 thus comprises in this example all the elements between said driving shaft 6 and said first element 2a.

Preferably, and as represented at figures 2 , 3 , 5, 6, 7 , said flattening device 13 also comprises a second intermediate body 8b, a second 2b of said two element 2a, 2b being freely pivotally connected to said second intermediate body 8b according to a third axis of rotation A ".

Advantageously, said second intermediate body 8a is substantially flat in shape having a second geometric center, and at least one of said third A "and fourth A '" axes of rotation is offset from said second geometric center. Preferably, the third A "and fourth A '" axes of rotation are both offset from said second geometric center.

Preferably, said second intermediate body 8a is of circular, oval or polygonal shape such as a square, a triangle or a rectangle.

Advantageously, said first intermediate body 8a cooperates with said second intermediate body 8b to convert a rotational movement of said first intermediate body 8a into a rotational movement of said second body intermediate 8b. More preferably, the direction of rotational movement of said second intermediate body 8b is opposite to the direction of rotational movement of said first intermediate body 8b.

Preferably, said first intermediate body 8a is cooperating with said second intermediate body 8b to rotate it along a fourth axis of rotation A '"offset and parallel to said first A, second A' and third A '" axes of rotation.

Preferably, said two intermediate bodies 8a, 8b cooperate mechanically with each other, so that the rotation of one in a clockwise direction causes rotation of the other in a counterclockwise direction, and / or vice versa. Preferably, said two intermediate bodies 8a, 8b are connected to a gear or a gear train ensuring the transmission of the rotational movement of one of said two intermediate bodies 8a, 8b. For example, each of said two intermediate bodies 8a, 8b is connected to a toothed wheel (of the same size or not, in the latter case one of said two wheels will be a pinion), said two gears being in contact with each other. the other to transmit the power by obstacle or via a transmission belt.

Alternatively, said flattening device 13 comprises another actuator which is also provided with a rotary motor shaft which is connected to said second intermediate body 8b to rotate it along said fourth axis of rotation A '' ', of the same way and with the same organs as those described above for rotating the first intermediate body 8a. The advantage of this configuration is that said two intermediate bodies 8a, 8b move in rotation independently of one another.

Advantageously, said two elements 2a, 2b each move in an elliptical translation movement (preferably a circular translational movement) respectively cyclic in phase opposition with each other. In other words, when one of said elements 2a, 2b performs an elliptical translation movement (preferably a circular translational movement) respectively in a counterclockwise direction, the other performs an elliptical translation movement (preferably a movement of circular translation) respectively in a symmetrical clockwise direction.

For example, and as represented in figure 3 (Apart from said membrane 12 and said support 1), said two elements 2a, 2b are arranged side by side, one being located to the left (which will be called left element 2b) and the other rather to the right (2a), and thus, when said membrane 12 is positioned below said elements 2a, 2b, against said support 1 itself located below said membrane 12, said right-hand element 2a performs an elliptical translation movement (preferably a respective circular translation movement) in a counterclockwise direction, and said left-hand element 2b performs an elliptical translation movement (preferably a circular translational movement) respectively in a clockwise direction.

Preferably, and as shown in figures 2 , 3 , 5, 6 and 7 said two substantially plate-shaped pieces 9a, 9b are arranged side by side, each having an inner upper corner 10a, 10b respectively, said two inner top corners 10a, 10b being adjacent to one of the other, and each of said two inner top corners 10a, 10b being connected to a different (and respective) of said two intermediate bodies 8a, 8b. Such a configuration is particularly advantageous in the case where said first intermediate body 8a is connected to said second intermediate body 8b.

Advantageously, said flattening device 13 of flexible membrane 12 further comprises at least two cheeks 21 between which are interposed said parts 9a, 9b to maintain the latter in said plane P, while allowing their respective displacement in said plane P.

Preferably, said flattening device 13 of flexible membrane 12 comprises at least a first guide conformation 23 (respectively) integral with one of said two parts 9a, 9b (or both), and at least a second conformation of guide 3a, 3b (respectively) integral with one of said cheeks 21 (or both), said first 23 and second 9a, 9b (respective) guide conformations cooperating to guide the (respective) displacement in cyclic translation of one of said two elements 2a, 2b (or both).

For example, said first guide conformation 23 may be a female part comprising a hole 23 made in said part 9a, 9b, and said second guiding conformation 3a, 3b may be a male part comprising a protuberance 3a, 3b which extends substantially perpendicularly to the plane P in which said part 9a, 9b fits, said protrusion being for example a roller 3a, 3b. Said male part is preferably designed to correspond to said female part. For example, said roller 3a, 3b is designed to fit into said slot 23 and to follow the edge thereof so as to guide the respective displacement in cyclic translation of said two pieces 9a, 9b and thus of said elements 2a, 2b, the drawing of said edge of said light 23 substantially corresponding to the path (respectively) describing a closed curve (respectively) of each of said elements 2a, 2b.

Said two elements 2a, 2b, said two intermediate bodies 8a, 8b, said support 1, and said two plate-like parts 9a, 9b may for example be made of metal, in particular stainless steel, another metal or an alloy but also plastic, wood, rubber or plastic. This list is in no way limiting, and said objects mentioned above can be made of any suitable material, including any material used in the manufacture of industrial tanning machine.

The invention also relates to a method of flattening flexible membrane 12, of the kind piece of animal skin. Said method is preferably implemented using the device described above, but may also be implemented by other means without departing from the scope of the invention. The foregoing description concerning the flattening device 13 is therefore valid, mutatis mutandis , for the method according to the invention.

According to the invention, said method of flattening flexible membrane 12 comprises at least one primary stretching stage, preferably in a first stretching direction E, in which at least two elements 2a, 2b each move in translation. cyclic according to a respective path describing a respective closed curve, said respective displacements in cyclic translation of said two elements 2a, 2b being at least partly symmetrical so that said two elements 2a, 2b come simultaneously and intermittently press said membrane 12 against a support 1 while moving away from each other to locally stretch said membrane 12, preferably in said first stretching direction E. In other words, during the primary stretching step, both elements 2a, 2b advantageously carry out respective cyclic displacements which are symmetrical to each other during at least a part of their respective cycle, and said two elements 2a, 2b preferably come into contact with said membrane 12 to press it against said support 1 for part or all of the duration of these respective symmetrical displacements. Thus, during the primary stretching step, said two elements 2a, 2b preferentially come into contact with said membrane 12 and then press it simultaneously against said support 1, then " slide " on the surface of the membrane 12 to stretching and removing the folds while moving away from each other, before moving away from the latter and / or no longer exert pressure on it. During the primary stretching step, the two elements 2a, 2b are preferably in contact with and / or in pressure of said membrane 12 during substantially the same time interval, and press said membrane 12 only intermittently, c that is, during a fraction of the period of the respective cyclic translation displacement of each of said two elements 2a, 2b. Said membrane 12 is advantageously stretched locally during the primary stretching step, that is to say preferably on only a portion of its surface, still more preferably a portion (or two half-portions) substantially elongated (s). ) and / or rectilinear (and / or aligned) of said surface. Advantageously, said two elements 2a, 2b, during the primary stretching step (more specifically during at least a portion of their respective cyclic translation displacements), locally press a portion (or they each press locally a respective half-portion) substantially elongated from the surface of said membrane 12.

Thus, during said primary stretching step, the membrane (12) is advantageously locally stretched in a first direction of stretching (E).

Preferably, each of said two elements 2a, 2b has a respective substantially straight elongate shape which extends longitudinally along a (same) main extension direction C.

Advantageously, during the primary stretching step, the stretching preferably taking place in said first stretching direction E, said membrane 12 is displaced relative to a fixed frame 22 on which said support 1 is mounted, according to a conveying direction H substantially perpendicular to said main extension direction C.

Preferably, during the primary stretching step, preferably in said first direction of stretch E, said membrane 12 is moved continuously relative to said frame 22 while said two elements 2a, 2b move themselves continuously in translation. respective cyclic (i.e. each of the two elements 2a, 2b moves in a respective cyclic translation).

Advantageously, the method according to the invention comprises a secondary stretching step, where the stretching of the membrane 12 is preferably carried out in a second direction of stretching F substantially perpendicular to said first direction of stretching E, in which, while said two elements 2a, 2b press locally said membrane 12, a tensile force is exerted on said membrane 12 in a traction direction T substantially parallel to said second stretching direction F. This secondary stretching step, in combination with the primary stretching step preferably in said first direction of stretching E, complements the flattening of said membrane 12. For example, the secondary stretching step, preferably in said second direction of stretching F, is substantially concomitantly with the stretching step according to said first stretching direction E. According to another example, the step of stretching secondary stretching, preferably in said second direction of stretching F) is wholly or partly done just before or just after the primary stretching step, preferably in said first direction of stretching E) and in particular at the moment where said two elements 2a, 2b locally press said membrane 12 against said support 1. Such a method of proceeding is of economic interest, particularly in the field of industrial tannery animal skins. Indeed, said skins arrive folded, re-saturated and inflated, and said flattening method provides a skin area as large as possible by unfolding said skin at best, and it is purchased by the piece and sold to the surface.

Preferably, said traction direction T is parallel to said conveying direction H, and in that the tensile force and the displacement of the membrane 12 (preferably of the animal skin component kind) are provided by one and the same way 4. Preferably, said second direction of stretching F is substantially parallel to said conveying direction H.

Advantageously, said drive means 4 comprises at least one rotary roller 4 frictionally driving said flexible membrane 12. Even more advantageously, said drive means 4 is formed by two rotary rollers 4, for example made of rubber, which make advantageously part of an industrial tannery machine, for example a slitter 14 or an introduction system 15.

Claims (15)

Device for flattening (13) of flexible membrane (12), of the animal skin component type, characterized in that it comprises at least two elements (2a, 2b) each designed to move in cyclic translation along a respective trajectory describing a respective closed curve, said respective displacements in cyclic translation of said two elements (2a, 2b) being at least partially symmetrical so that said two elements (2a, 2b) come simultaneously and intermittently press said membrane (12) against a support (1) while moving away from each other to locally stretch said membrane (12). Flattening device (13) of flexible membrane (12) according to the preceding claim, characterized in that the respective trajectory of each of said two elements (2a, 2b) is substantially circular, said two elements (2a, 2b) moving preferably in two respective opposite directions to each other. Device for flattening (13) of flexible membrane (12) according to claim 1 or 2, characterized in that each of said two elements (2a, 2b) has a respective substantially straight elongate shape which extends longitudinally in a direction d main extension (C). Device for flattening (13) flexible membrane (12) according to one of the preceding claims, characterized in that said two elements (2a, 2b) are arranged to stretch said membrane (12) in at least a first direction of stretching (E). Flattening device (13) of flexible membrane (12) according to the preceding claim and claim 3, characterized in that said first direction of stretching (E) is substantially parallel to said main extension direction (C). Flattening device (13) for flexible membrane (12) according to claim 4 or 5, characterized in that said first direction of stretching (E) is substantially perpendicular to a conveying direction (H) in which a driving means (4) causes said diaphragm (12) to move relative to a fixed frame (22) on which said support (1) is to be mounted, said conveying direction (H) being preferably substantially perpendicular to said main extension direction (C). Device for flattening (13) flexible membrane (12) according to claim 3 or 5 and optionally claim 4 or 6, characterized in that it comprises traction means (4 ') of said membrane (12) according to a traction direction (T) perpendicular to said main extension direction (C) of said two elements (2a, 2b), said traction means (4 ') cooperating with said elements (2a, 2b) for stretching said membrane (12 ) in said traction direction (T), said traction direction (T) being advantageously parallel to said conveying direction (H), and said traction means (4 ') being preferably formed by said driving means (4); ). Flattening device (13) of flexible membrane (12) according to one of the preceding claims, characterized in that said two elements (2a, 2b) are substantially identical and have respective displacements completely symmetrical. Device for flattening (13) flexible membrane (12) according to one of the preceding claims, characterized in that it comprises: an actuator (11) which is provided with a rotary motor shaft (6), a kinematic chain (7) connecting said motor shaft (6) to at least one first (2a) of said two elements (2a, 2b) for converting the rotation of the motor shaft (6) into a first elliptic movement of said first element (2a). Device for flattening (13) flexible membrane (12) according to one of the preceding claims, characterized in that it also comprises a first intermediate body (8a), and in that a first (2a) of said two elements (2a, 2b) is freely pivotably connected to said first intermediate body (8a) along a first axis of rotation (A). Device for flattening (13) flexible membrane (12) according to claims 9 and 10, characterized in that said motor shaft (6) is connected to said first intermediate body (8a) to rotate it along a second axis of rotation (A ') which is parallel and offset from said first axis of rotation (A). Flattening device (13) for flexible membrane (12) according to claim 10 or 11, characterized in that it also comprises a second intermediate body (8b), and in that a second (2b) of said two elements (2a, 2b) is freely pivotally connected to said second intermediate body (8b) along a third axis of rotation (A "), said first intermediate body (8a) cooperating preferably with said second intermediate body (8b) to convert a movement rotating said first intermediate body (8a) into a rotational movement of said second intermediate body (8b). Method for flattening flexible membrane (12), of the animal skin component type, characterized in that it comprises at least one primary stretching stage, in which at least two elements (2a, 2b) each move in cyclic translation according to a respective trajectory describing a respective closed curve, said respective displacements in cyclic translation of said two elements (2a, 2b) being at least partially symmetrical so that said two elements (2a, 2b) come simultaneously and intermittently press said membrane (12) against a support (1) while moving away from each other to locally stretch said membrane (12). A method of flattening flexible membrane (12) according to the preceding claim, characterized in that each of said two elements (2a, 2b) has a respective substantially straight elongate shape which extends longitudinally in a main extension direction (C ) in that during said primary stretching step said membrane (12) is stretched locally in a first stretching direction (E), in that during the primary stretching step, said membrane (12) is displaced relative to a fixed frame (22) on which said support (1) is mounted, in a conveying direction (H) substantially perpendicular to said extension direction principal (C), and in that during the primary stretching step, said membrane (12) is continuously displaced relative to said frame (22) while said two members (2a, 2b) are continuously moving themselves in respective cyclic translation. A method of flattening flexible membrane (12) according to the preceding claim, characterized in that it comprises a secondary stretching step, wherein the stretching of the membrane (12) is carried out in a second direction of stretching ( F) substantially perpendicular to said first direction of stretching (E), wherein, while said two members (2a, 2b) locally press said diaphragm (12), a tensile force is exerted on said diaphragm (12) according to a traction direction (T) substantially parallel to said second stretching direction (F), said traction direction (T) being preferably parallel to said conveying direction (H), and the traction force and the displacement of the membrane (12) being preferably provided by one and the same drive means (4).

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