EP1202847A1

EP1202847A1 - Method and device for making staves

Info

Publication number: EP1202847A1
Application number: EP00953268A
Authority: EP
Inventors: Frédéric Voisin
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-07-20
Filing date: 2000-07-20
Publication date: 2002-05-08
Also published as: FR2796586A1; FR2796586B1; WO2001005563A1; AU6578500A

Abstract

The invention concerns a method for bending, compressing and jointing staves (d) to make barrel or cask shells. It consists, subsequent to the standard processes of cropping, planing, complete or partial grooving, optional shaping, in carrying out the following steps which consist in: setting the stave at the desired curvature along the longitudinal axis, by compressing the stave (d) along its thickness first at its centre (4) then gradually towards the ends (3) while simultaneously and gradually bending the whole stave; by compressing likewise in the longitudinal direction the fibres of the stave inner surface; while the stave has the desired curvature, compressing the stave over its whole surface to bring its initial thickness to an at least slightly lesser thickness, and while the stave has the desired curvature and after having more or less compressed its fibres over its whole surface, cutting (14) its joints along the desired radius for the barrel shell.

Description

Method and device for manufacturing staves

The present invention relates to a method of compression, bending and joining of staves to manufacture barrels or barrels, as well as a device for the implementation of this process.

Oak has the property of possessing transverse fibers in large quantities called medullary rays; these spokes are more impermeable than other fibers so that they form, correctly arranged in the staves, a sort of sealing barrier. The staves are planks with particular properties used in the field of cooperage obtained by cutting logs generally in oak in the direction of the medullary rays and therefore according to the grain of the wood; the orientation of the medullary rays of the staves is essential with regard to their sealing properties and their oenological virtues; if the shaft used has a significant curvature, then the staves will be cut also according to this curvature, similarly if the tree used has an exaggerated spin, then the staves can also be cut twisted.

However, the oaks used in Europe for the manufacture of barrels often have very different qualities in terms of tightness because their channels are more or less blocked by natural substances, thyls or minerals; these substances can also be degraded according to the way of preserving the logs or the staves and according to the process used in the manufacture of barrels. The staves are stored outdoors for a period ranging from 6 to 36 months, without particularly protecting them from bad weather, with a view to a beneficial modification of their physical and chemical structure.

The porosity of the staves is very variable and depends above all on several factors: origin, forestry and condition of the trees, conservation and treatment of logs and staves.

A barrel or a barrel is composed of a set of long machined and curved staves called staves, the set of staves forming the body is also called hull, two bottoms assembled with short machined and flat staves are necessary for the closing of the shell, all of these pieces of wood are held in place by powerful wooden or metal circles, the bottom pieces are assembled by means of wooden or metal studs; the tightness of the assembly is obtained only by the quality of the assemblies and the tightening of the parts together, the use of sealing products being highly detrimental to the oenological virtues of the barrels. The different machining operations of a stave are: shortening or cutting to length; bashing or planing in convex form at the external mean radius of the barrel; the recess or planing in concave shape at the interior mean radius of the barrel; the perfect jointing or cutting of the two faces forming the joints between the spindle-shaped staves and at the angle necessary to obtain the shape of the barrel; the trimming or milling of the two ends of the stave to form the jable consisting in particular of a groove to receive the bottom of the barrel.

The method currently most used in the manufacture of barrels consists of joining the staves without first modifying their curvature or natural twist therefore by proceeding to the jointing operation according to the flat development of the subsequent shape that the stave will take, then partially assemble the staves to form a rose which is strongly heated by means of a wood fire placed in the center of the rose or any other means in order to obtain a sufficient temperature to succeed in bending all of the staves simultaneously using a cable wrapped around the rose for example and then obtaining the closure of the rose which becomes a shell similar to a barrel without its two bottoms; the shell is then tightened strongly by powerful mounting circles which compress the staves against each other, this circular compression comes to compensate for any machining defects, then it is reheated inside more or less strongly to modify the taste wood, the rim is machined after cooling.

This process does not keep the wood fibers in areas subject to high stresses; it is not satisfactory with regard to the rate of repairs made necessary as a result of leaks or ruptures of staves; this rate is frequently of the order of 10% of the number of hulls manufactured; the staves must be perfectly oriented and machined and despite this and randomly, there are many problems in the manufacture of barrels and later in the use of these barrels. In addition, this process does not easily make it possible to obtain satisfactory staves in twisted or curved staves or in staves having small knots or having slight movements of fibers, defects which are encountered very frequently and which coopers do not hardly appreciate because of their implementation difficulties.

The staves from these staves are therefore not all capable of retaining liquids and may need to be replaced or clogged at the time of manufacture or during use, which is highly detrimental. There are also very frequently blisters on the concave part of the staves, these cavities in the wood considerably weakening the solidity, the tightness and the quality of the barrels.

Indeed, the bending of a piece of any thickness involves two strings of different lengths, therefore of different radii, the concave face being more curved than the convex face. Wood fibers are compressible but not very stretchable, bending a piece of wood is mainly to control the compression of the fibers of the concave face and avoid stretching the fibers of the convex face.

The glass transition temperature can be assimilated to the temperature at which a material softens and can maintain, durably and without deterioration of its mechanical qualities, the shape which is printed on it until cooling to a lower temperature.

The glass transition temperature of oak stave is between 40 and 70 ° C, it is this temperature which is sought in the traditional process, but which is largely exceeded on the surface inside the hull and rarely reached early enough at the heart of the staves at the time of their bending.

After bending and to modify the taste of the wood inside the shell compressed by mounting circles, the second heating makes it possible to reach the glass transition temperature of the oak oak, which favors the adjustment of the staves between them; as the shell is left assembled in this way until complete cooling, the shape given to the staves is therefore permanently printed.

It is therefore in particular the operation of bending the staves which is delicate and a source of problems in the traditional process, in particular breakage and / or separation of fibers at the central zone of the stave, that is to say blisters and / or staves broken or split.

The possibility of bending and compressing the wood therefore depends very much on the intensity of the pressures exerted, on the temperature and on the humidity of the wood.

The return to the initial state or the resumption of initial shape of a piece of compressed wood also depends a lot on the state of the fibers: intensity of the compression which was exerted, cycle and thermal stage, blindness.

Controlling the bending of staves therefore amounts to permanently deforming the fibers making up the staves without significantly altering their structure and mechanical strength.

Document FR 2 587 268 dating from 1986 describes a method and a device for obtaining identical staves by placing them one after the other in a profiled clamping mold while maintaining a pressure and heating the assembly; before removing the part, the edges of the mold are used to cut the joints.

However, this document does not mention a process or device for bending and joining staves of any width.

Document DE 120 909 describes a machine for bending staves of fixed length. In addition, the machine does not allow the compression to be properly applied to the stave.

Document DE 46 341 describes a machine for manufacturing staves. The staves obtained have a predetermined length and width. In addition, the bending of the stave is not carried out under satisfactory conditions.

The present invention relates to a method and a device for bending, compressing and joining staves for the manufacture of barrel hulls or barrels with optimized yield, productivity and reliability while also optimizing the oenological qualities of the barrels or barrels.

After having previously shortened, shattered, completely or partially hollowed out, these staves by known and commonly used means, this process consists in carrying out, automatically or not, the following steps: - put the stave at the desired curvature along the longitudinal axis , compressing the stave according to its thickness, first in the center then gradually towards the ends while simultaneously and gradually bending the entire stave; by also compressing in the longitudinal direction the fibers of the internal face of the barrel without causing the longitudinal fibers of the external face to break at the time of bending or subsequently;

- while the stave is at the desired curvature: compress the stave over its entire surface to reduce its initial thickness to a thickness slightly or markedly less in proportion and automatically or not, to the porosity of the stave observed initially; and

- While the stave is at the desired curvature and after having more or less compressed its fibers over its entire surface, cut its joints according to the desired radius, for example by milling or planing. After these operations, the shell can be assembled immediately or later with these staves by metal mounting circles.

According to a first mode of implementation of the method, the bending of the stave and the cutting of the seals of the stave are carried out using a single machine which essentially comprises a press with variable curvature and tools for cutting the seals . In this case, the two joints are made successively.

According to a second embodiment of the method, the bending is carried out using a first machine and the stave thus formed is placed on a second machine for cutting the joints.

In this case, the two joints can be made simultaneously.

The hulls thus produced can be heated to modify the taste of the wood and then the other known and current operations are completed, making it possible to obtain barrels or barrels. Whatever the shape or the initial weakness of the stave following the presence of small knots or movements of fibers or excessive porosity, such a process allows obtaining real staves with mechanical and oenological qualities much more reliable than by the classic process most commonly used which consists, after joining, of simultaneously bending the staves by heating and clamping in pink, without maintaining the wood fibers in areas subject to high stresses.

The advantage of the process therefore appears here, avoiding the degradation of the initial sealing qualities avoiding the risk of rupture of the external fibers of the stave, avoiding the risk of leaks linked to excessive porosity or to the presence of small knots or light fiber movements, making it possible to adjust the staves between them in a much more precise way, the jointing being made curved stave, and eliminating the problems consecutive to the replacement of defective staves not waterproof or broken thus minimizing the loss of wood which is the weakness of the traditional process.

The bending operations, whatever the shape and the initial quality of the staves, are greatly facilitated both in terms of speed and safety of execution as in effort to produce, therefore the yield and the productivity are also optimized.

In order to optimize the manufacture of barrels or barrels giving appreciated wine results, the possibility of pushing back the limits of operating difficulty is an appreciable and significant factor. The present invention also relates to an associated device for implementing the method of the invention.

To this end, the associated device for implementing the method of the present invention is characterized in that it comprises a set of means making it possible to bend, compress, join staves of any width, even very small, automatically or not so as to to make hulls of barrels or barrels with staves previously shortened, sore, hollowed out completely or partially. These means are:

- bending means to the desired shape, used simultaneously with; - means for holding and compressing according to the thickness, used simultaneously with;

- means for maintaining the length of the external face of the staves, used simultaneously;

- Longitudinal compression means of the internal face of the staves; then while maintaining arched to the desired shape; - means of compression and reduction of the thickness according to the porosity of the staves;

- means for precise cutting of the two faces forming the joints between the staves and along the radius of the barrel; and - means for placing, moving and ejecting the staves before, during and after the bending, compression and jointing operations.

The assembly of the bending, holding and compression means will preferably comprise a press of shape corresponding to the desired final curvature, the stave being disposed between the upper and lower parts of this press.

Its lower heating part is preferably convex in the transverse and longitudinal direction corresponding to a portion of the interior of the barrel, and has a fixed curvature. Its upper part corresponding to the same symmetrical portion of the interior of the barrel is preferably:

- of concave shape in the transverse direction;

- movable in the vertical direction;

- deformable in the longitudinal direction from a very small curvature opposite to the hanger of the barrel sought until an identical curvature, being capable of exerting pressure first at the center of the hanger sought, then gradually towards the ends for achieve the shape of the desired hanger and maintain as a priority the areas where the fibers of the stave are subjected to high stresses; - slightly and simultaneously reducing its total length when it is brought to the desired hanger relative to its length when this lower part is in the rectilinear position, which ensures the maintenance of the external fibers and therefore allows the longitudinal compression of the fibers of the face internal of the stave during the bending operation; - coming to deform until parallel to the lower part to somehow form a mold of the stave;

- Being capable of compressing the stave previously bent over its entire surface to reduce its initial thickness to a thickness slightly or markedly less in proportion and automatically or not, to the porosity of the stave observed initially. The means for precise cutting of the two faces forming the joints between the tubes and along the radius of the barrel will preferably be associated with the press described above and will comprise two cutting tools, one on each side of the press, each being capable of one after another to cut the joints of the stave according to a plane passing through the central axis of the barrel.

The precise means of placing, moving and ejecting the staves before, during and after the bending, compression and jointing operations will preferably include: - a chain or a belt at the entry and exit of the press; and

- two stops articulated along the axis of the barrel on each side of the stave, capable of positioning the stave in the press during each of the steps described above and which can serve as a retractable stop to position the stave very exactly on one side then on the other side of the press, in an alignment for jointing.

All the bending, holding, compression and cutting, positioning, displacement and ejection means can be automated according to a program for optimizing the different sequences defined by the general or particular characteristics of the staves.

The entire device can be adapted according to the desired curvature thanks to different sets of shims and stops corresponding to the different shapes sought.

Other characteristics and advantages of the present invention will emerge from the description which follows of embodiments of the invention given by way of example only, representing a device allowing the implementation of the method described above and opposite. annexed sketches on which:

- Figure 1A is a partial schematic view in cross section of all the bending, holding, compression and cutting means, positioning, displacement and ejection;

- Figure 1 B is a top view of the means shown in Figure 1a;

- Figures 2, 3 are schematic longitudinal front views of a press ensuring the bending, holding, compression means, shown in the two positions; - Figures 4, 5 and 6 are simplified top views showing the different positions occupied by the stave relative to the press; and

- Figure 7 is a vertical longitudinal sectional view of the press along VII of Figure 1A.

The lower part 1 of the press is fixed. Its upper face 1a has a fixed curvature which is that which the stave must take.

It corresponds to an angular portion of the interior of the barrel, its surface is therefore convex in the transverse and longitudinal direction. It is maintained at the desired temperature 120 ° C. for example using electrical resistances or by internal circulation of liquid or vapor, not shown in the figures.

The upper part 2 of the press is movable vertically and deformable, in its longitudinal direction. It always remains concave in the transverse direction.

It is movable in the vertical direction.

It is deformable in the longitudinal direction, from a very small inverse curvature to the hanger of the barrel sought in Figure 2 up to an identical curvature in Figure 3. It is capable of exerting pressure first at the center of the desired hanger thanks to the jack 4 which retracts into the movable block 3, then progressively in the direction of the ends to reach the shape of the desired hanger and to maintain priority in the areas where the fibers of the stave are subjected to high stresses. As shown in Figure 7, the upper part 2 is fragmented into small lengths 2a proportional to the desired curvature, articulated together according to a certain rigidity obtained for example using a powerful spring leaf 2b; these lengths will be sufficiently spaced from one another to allow a reduction in the total length of the upper part when the latter is brought to the hanger, which ensures the maintenance of the external fibers and therefore allows the longitudinal compression of the fibers of the internal face of the stave during the bending operation.

It deforms until it is parallel to the lower part, in a way forming a mold of the stave. It is guided by a movable block 3, the concave underside of which 3a serves as a template on which it abuts. The curvature of this lower face 3a is parallel to that of the face 1a of the lower part 1 of the press. The movable block 3 is itself guided by two walls constituting another element 5 of the press; this block is actuated for example using a jack coupled and hidden by these walls 5 and not shown in the diagrams.

It is important to emphasize that the spring 2b must have significant rigidity. During the initial actuation of the jack 4, the central part of the spring applies pressure to the central zone of the stave, the spring 2b remaining rectilinear. When lowering the block 3 with its concave active face 3a, the periphery 3b of this active face comes into contact with the periphery of the spring 2b and thus initiates the taking of regular curvature of the spring, curvature which is transmitted to the stave. As the block 3 is lowered, the curvature of the spring and therefore of the stave gradually increases until the block 3 comes into abutment. In this position, the stave is compressed between two parallel surfaces, namely the face 3a of the block 3 via the spring 2b and sections 2a and the face 1a of the lower part 1 of the press.

The stops 10, symmetrical with respect to the press, allow very precise positioning of the stave D with respect to the upper 2 and lower 1 parts of the press and are articulated around an axis corresponding to that of the barrel 13 to be produced. The stops 10 are controlled by jacks 12. These stops 10 also serve to tighten the longitudinal edges of the staves on its central third and they have a thickness slightly less than that of the stave to be produced. They are capable of very precisely maintaining the central portions of the longitudinal edges of the staves during the bending and compression operations. There is shown at 14 one of the tools for machining the joint, for example a milling cutter, the whole machine having two symmetrical ones. These tools are retractable to allow the press to be supplied with staves from the supply conveyor 15 and the ejection of the staves to the outlet conveyor 17. The transfer of the staves D from the conveyor 15 to the press is carried out by two symmetrical cylinders 16 which enclose the stave as the shows figure 1b better. The final positioning is achieved by the stops 10, as already explained.

The ejection of the stave D from the press towards the outlet conveyor 17 is also obtained by means of the jacks 16. A retractable support plate 19 controlled by the jack 18 makes it possible to ensure a continuous movement path for the staves between the press and the output conveyor 17.

The sequence of operations is as follows:

- first opening of the press according to FIG. 2 making it possible to insert the stave D by means of the stops 10 so that the upper part 2 is in the rectilinear position, the jack 4 in the extended position and the movable block 3 in the retracted position;

- Installation of a stave D at the entrance of the press, by the chain 15 and the jacks 16; - tightening then positioning of the stave D in the center of the press by the stops 10;

- First compression by the central part of the stave then on the whole of its surface by the upper part 2; the jack 4, retracting in the movable block 3, acts beforehand and remains at a pressure lower than the latter; the duration of this compression operation can vary from a few seconds to a minute, the temperature of the lower part 1 can vary from 40 to 120 ° C, these two values are established according to the nature of the stave and in particular according to its shape and its initial porosity; The pressure to be applied is advantageously between

10 kg / cm ² and 90 kg / cm ² . This pressure depends on the duration of pressure application, the temperature, the humidity of the stave and the desired thickness reduction. Under standard temperature and humidity conditions (for example 90 ° C), the thickness reduction effect will be obtained from approximately 40 kg / cm ² .

- second opening of the press so as to release the curved stave, the upper part being maintained in the curved position, the jack 4 being blocked in the retracted position, the movable block 3 being raised only at a very low value; - very precise positioning of the stave by the movable stops 10 according to a first alignment for jointing; - second compression according to the hanger sought by simple compression of the stave between the lower and upper parts over its entire surface;

- cutting of the first joint by rotation and back and forth translation of the first milling disc;

- third opening of the press similar to the second opening;

- very precise positioning of the stave by the movable stops 10 in a second alignment for jointing; - third compression identical to the second;

- cutting of the second joint by rotation and back and forth translation of the second milling disc;

- fourth opening of the press similar to the first opening; - Ejection by the stops 10 on the chain 14 of the stave D which has become bent, compressed and joined, therefore ready to be assembled in pink;

- new opening of the press similar to the first allowing to insert a new stave D and to reproduce all the previous operations.

These different operations are illustrated in FIGS. 4 to 6. It will be noted in these figures that the lower part 1, like the upper part 2, has edges 1b and 1c, in their longitudinal direction, which are not straight. They have a curvature corresponding to that of the seals to be produced on the stave D.

The entire device can be managed for example using a programmable automaton using a set of sensors and safety devices informing it of the respective position of each element so as to optimize the sequence and the duration of the different sequences according to the general or particular characteristics of the staves; so that the operator only has to modify two or three parameters depending on the initial nature of a batch of staves and according to the characteristics sought, his work essentially consisting in placing a large quantity of staves on the chain 15 simultaneously which gives him enough time to resume the staves thus machined on the chain 14 and assemble them in pink, or any other work. In the preceding description, the operations of bending the staves and cutting the joints are carried out using a single machine which essentially comprises a press with lower 1 and upper 2 parts, and cutting means positioned with respect to the press to make the joints of the staves.

However, it would not go beyond the invention if the bending was carried out on a first machine shown in Figures 1 to 3 and 7, with the exception of the cutting means, and if the cutting of the joints was carried out on another machine joint comprising a press whose upper and lower parts would have fixed curvatures and a reduced width less than that of the staves to be produced and two cutting tools capable of simultaneously making the two seals of the staves.

Claims

1. A method of bending, compressing and joining staves of any width, even very small, for the manufacture of barrel shells or barrels, characterized in that it consists, after the current operations of shortening, dolage, total emptying or partial, cutting or not, to carry out the following steps:

- put the stave at the desired curvature along the longitudinal axis, compressing the stave according to its thickness first at the center then gradually towards the ends while simultaneously and gradually bending the whole of the stave; by also compressing in the longitudinal direction the fibers of the internal face of the barrel without causing the longitudinal fibers of the external face to break at the time of bending or subsequently; - while the stave is at the desired curvature, compress the stave over its entire surface to reduce its initial thickness to a thickness at least slightly less in proportion to the porosity of the stave observed initially; and

- while the stave is at the desired curvature and after having more or less compressed its fibers over its entire surface, cut its joints according to the desired radius of the barrel shell or barrel.

2. Method according to claim 1, characterized in that the joints are cut one by one of the stave, by implementing the following steps:

- the compression applied to the stave is eliminated;

- We move the stave to achieve a first alignment of jointing;

- Said compression is again applied to the stave thus positioned;

- The first joint of said stave is cut;

- the compression applied to the stave is again removed;

- We move the stave to achieve a second alignment of jointing; - Said compression is again applied to the stave thus positioned; and - the second joint of said stave is cut.

3. Method according to claim 1, characterized in that the bending of the stave is carried out using a press and the cutting of the joints using a separate machine.

4. Method according to claim 2, characterized in that the bending of the staves and the cutting of the joints are carried out using the same machine comprising a press.

5. Device for bending, compressing, joining the staves of any width, even very small, in order to manufacture shells of barrels or barrels with staves previously shortened, splayed, completely or partially hollowed out, characterized in that it comprises:

- bending means in the longitudinal direction to the desired shape to apply pressure to said stave first at its center and then towards its ends, used simultaneously; - means for holding and compressing according to the thickness, used simultaneously with;

- Means for simultaneously maintaining the length of the external face of the staves;

- Means for compressing longitudinally and simultaneously the internal face of the staves;

- means for compressing and reducing the thickness of the staves according to their porosity;

6. Device according to claim 5, characterized in that said means comprise a press of shape corresponding to the desired final curvature, the stave being disposed between the upper and lower parts of this press, its lower part corresponding to a portion of the inside the barrel, and being convex in the transverse and longitudinal direction, and being provided with heating means; and its upper part: - corresponding to the same symmetrical portion of the outside of the barrel; - being of concave shape in the transverse direction;

- being movable in the vertical direction; and

- having a curvature which is deformable in the longitudinal direction, from a very small curvature opposite to the desired hanger up to a curvature parallel to that of the lower part;

- To exert pressure first at the center of the desired hanger, then gradually towards the ends to reach the shape of the desired hanger and maintain priority areas where the fibers of the stave are subjected to high stresses; - And to compress the stave previously bent over its entire surface to reduce its initial thickness to a thickness at least slightly less in proportion to the porosity of the stave observed initially.

7. Device according to claim 6, characterized in that said upper part of the press consists of a plurality of sections hinged together by elastic return systems whereby the total length of the upper part is slightly reduced when the latter is brought to the desired hanger with respect to its length when this upper part is in the rectilinear position, this being ensured by the fragmentation into sections of the concave upper part in small lengths proportional to the desired curvature, articulated between them and sufficiently spaced apart relative to each other to allow this reduction in length which ensures the maintenance of the external fibers and therefore allows the longitudinal compression of the fibers of the internal face of the stave during the bending operation.

8. Device according to any one of claims 5 to 7, characterized in that it comprises two arms on each side of the press articulated along the axis of the barrel, serving as retractable stop to position the stave very precisely relative to at the top and bottom of the press.

9. Device according to one of claims 5 to 8, characterized in that it comprises two rotary and independent cutting tools located and fixed on either side of the press, movable in translation, and cutting one after the other the joints of the stave already bent along a plane passing through the central axis of the barrel.

10. Device according to one of claims 6 to 9, characterized in that it further comprises a supply chain and a discharge chain located on either side of the press on which the staves are arranged transversely and centered, the first chain bringing the staves one by one to the press.

11. Device according to one of claims 5 to 9, characterized in that it further comprises a centralization of the various commands and an optimization of the sequences according to the general or particular characteristics of the staves 12. Device according to claim 11, characterized in that said orders are automated.