Patent Publication Number: US-2021187780-A1

Title: Stave, Wooden Barrel with Staves, and Method for Producing Staves

Description:
BACKGROUND OF THE INVENTION 
     The invention concerns a stave for producing wooden barrels, a wooden barrel with staves, as well as a method for producing staves. 
     It is known to form wooden barrels of curved staves that, with their longitudinal sides, rest tightly against each other. The staves extend across the height of the wooden barrel and are usually surrounded by a hoop at the upper and the lower end with which the staves are held together. The staves are in general split along the natural fibers of the wood. When producing barrels, they are brought by a steam bending method into a curved shape and held together with the hoops. When producing the wooden barrels, many remnants remain that are not used and constitute waste. 
     The invention has the object to produce the staves and the wooden barrels in a cost-efficient manner by saving raw materials. 
     SUMMARY OF THE INVENTION 
     The object is solved for the stave of the aforementioned kind in accordance with the invention in that the staves are assembled from individual segments that are connected to each other fixedly at end faces. For the wooden barrel, the object is solved according to the invention in that the staves according to the invention are placed against each other with their narrow sides in a seal-tight manner. In the method, the object is solved according to the invention in that the individual segments are joined together, contacting each other at end faces, to a raw stave. 
     The stave according to the invention is characterized in that it is assembled from individual segments which are connected to each other fixedly at end faces. The individual segments are shorter pieces of wood that are assembled such that the stave can have the required length for producing the wooden barrel. In this manner, remnants can be employed also so that the wooden barrels can be produced in a manner so as to save raw material. In general, the raw stave formed by joining together individual segments is too long. Prior to or after assembly of the raw stave, the respective terminal individual element is cut such that the raw stave has the desired length. 
     The individual segments are connected to each other in an advantageous manner at end faces by form fit. In this way, the individual segments are connected to each other fixedly to the stave. The form fit must act primarily in length direction of the stave with respect to the future loading and can be realized in various ways, for example, by a kind of dovetail connection or by so-called click profiles. Tongue and groove connections or finger joint connections are conceivable with use of a food-compatible adhesive as material-fused and friction connections. 
     In a simple configuration, the individual segments are of a straight embodiment. 
     In an advantageous embodiment, at least one end face of the individual segments is embodied so as to be inclined at an acute angle relative to a plane that extends perpendicularly in relation to an outer side of the individual segments. In this way, the individual segments are connected to each other by abutting each other such that they extend relative to each other at the angle of inclination of the end faces. When in this manner a plurality of individual segments are placed next to each other, then a stave will result that extends approximately in a curved shape across its length. 
     The form fit connection between the individual segments can be designed in an advantageous manner such that neighboring individual segments with their inclined end faces rest flat against each other. In this way, the staves that are formed of the individual segments have a high strength and stability. In particular, it is prevented in this way that the individual segments in the joining area separate from each other. The individual segments located at the two ends of the stave have advantageously at their free end face no form fit element but are designed planar, for example. These free end faces of the terminal individual segments form then the upper and the lower rim of the wooden barrel that is formed by the staves. 
     By means of the form fit connection, it is also possible in a very simple manner to connect the individual segments with sufficient seal-tightness to each other so that the contents of the barrel cannot escape through the form fit connections to the exterior. 
     It is possible to connect the connection between the individual segments with each other not only by form fit but in addition also with material fusion, for example, with an adhesive agent. Then a proper seal-tightness of the connecting regions between the neighboring individual segments is realized. 
     The staves can be placed flat against each other with their narrow sides extending in longitudinal direction during manufacture of the wooden barrels. However, there is also the possibility to provide at these narrow sides form fit elements with which neighboring staves are placed next to each other in a seal tight manner. In this way, a very high strength of the wooden barrel and a reliable sealing action are obtained. 
     The wooden barrel according to the invention is characterized in that it can be assembled efficiently and with raw material savings from staves which, in turn, are formed of individual segments. They can be assembled very easily and with minimal expenditure to staves. 
     In the method according to the invention, the individual segments that are formed by wooden parts are first joined together, contacting each other at end faces, to a raw stave. Depending on the embodiment of the end face connection, this can be done by pushing together and pressing together in transverse direction or, in case of a finger joint connection, with addition of an adhesive agent by compression in length direction. Joining together can be done by a machine, partially by a machine, or manually. When using a click profile, the individual segments are simply clicked together in length arrangement. The method according to the invention enables a simple, cost-saving, and material-saving manufacture of the raw staves. 
     A particularly simple method results when the individual segments are machined at end faces such that individual segments contacting each other extend at an angle relative to each other after joining. Due to the angled position of the individual segments relative to each other, a stave is provided that extends curved across its length. 
     Advantageously, straight wooden parts are used as individual segments. In this context, the curvature is not continuous but is comprised of individual straight sections that are positioned angularly relative to each other 
     In an advantageous embodiment, the raw staves can be subsequently machined at their topside and at their bottom side in a throughfeed method for forming an outer or inner side that is convexly or concavely curved across its length. The throughfeed method enables an efficient, fast, and inexpensive production of the stave. 
     The raw stave formed after assembly of the individual segments is transported with a first narrow side supported on a support through a processing machine. As it passes through, the two longitudinal sides of the raw stave that form the outer side and the inner side of the finished stave are machined with at least one tool, respectively. The two tools engage the raw stave at the oppositely positioned longitudinal sides. During passage of the raw stave, the two tools rotate about their axes and machine the two longitudinal sides at high speed. By means of the processing machine, an effective, fast, and precise machining of the raw staves is ensured. 
     Advantageously, with one tool the outer side which is convex transverse to the length direction is produced and with the other tool the inner side of the stave which is concave transverse to the length direction is produced. The corresponding tools have correspondingly a concave or convex working region. 
     Since the raw stave is curved across its length, the two tools during passage of the raw stave through the processing machine are moved transversely to the feed direction, controlled in accordance with the curvature of the raw stave, in order to obtain the desired curvature across the length of the raw stave. 
     Advantageously, the exposed second narrow side of the raw stave is machined in the same processing machine with at least one additional tool. 
     The raw stave is thus machined in one pass through the first processing machine on three sides. 
     The curved raw stave is transported linearly through the processing machine which accordingly can be of a simple construction. 
     For guiding the raw stave through the processing machine, at least one guide groove extending in the feed direction is advantageously introduced into the first narrow side. For this purpose, the processing machine can be provided, for example, with a lower horizontal spindle on which a groove milling tool is seated with which the guide groove can be milled into the first narrow side. 
     A guide web at the machine that extends in feed direction can engage the guide groove so that the raw stave that is curved in its length direction can be properly linearly transported by means of the feed elements through the processing machine. 
     After passing through the processing machine, the raw stave that has been machined on the three sides is turned such that the first narrow side provided with the guide groove is exposed and can be machined with a corresponding tool whereby also the guide groove is removed. Then the stave is finish-machined and can be used for producing the wooden barrel. 
     In order for a proper machining to be possible at this narrow side at the partially machined raw stave, the latter is guided at both longitudinal sides in the feed direction. 
     In this context, it is advantageous when the partially machined raw stave with its two ends is guided at a stop. It extends parallel to the feed direction and ensures that the partially machined raw stave is guided reliably during machining of its corresponding narrow side. 
     Also, it is advantageous when a guide that is extending in the feed direction is contacting the outer side of the partially machined raw stave that is convex between its ends. 
     The partially machined raw stave is thus properly supported between the stop and the guide during machining of the second narrow side. 
     The subject matter of the application not only results from the subject matter of the individual claims but also from all specifications and features disclosed in the drawings and the description. They are claimed, even if they are not subject matter of the claims, as important to the invention, provided they are individually or in combination novel in comparison to the prior art. 
     Further features of the invention result from the additional claims, the description, and the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in more detail with the aid of some embodiments illustrated in the drawings. 
         FIG. 1  shows in perspective illustration a wooden barrel according to the invention, produced from staves according to the invention, without cover. 
         FIG. 2  shows in an enlarged illustration and in a side view an individual segment of a stave according to the invention. 
         FIG. 2 a    shows in an enlarged illustration form fit elements provided at the ends of the individual segment according to  FIG. 2 . 
         FIG. 3  shows in a side view a stave assembled of individual segments in the raw state. 
         FIG. 4  shows in perspective illustration the stave according to  FIG. 3 . 
         FIG. 5  shows in perspective illustration the stave according to  FIG. 3  in machined state, wherein the separation lines between the individual segments placed next each other are not illustrated. 
         FIG. 6  shows in simplified illustration three tools for machining the stave. 
         FIG. 7  shows in schematic illustration two guides for the stave that is machined with a top tool. 
         FIG. 8  shows in schematic illustration machining of the stave according to the invention on a first processing machine. 
         FIG. 9  shows in schematic illustration machining of the stave according to the invention on a second processing machine. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows in schematic illustration a wooden barrel  1  that is assembled of staves  2 . They are curved across their length and are positioned with their narrow longitudinal sides liquid-tightly against each other in known manner. They are surrounded from the top end to the bottom end at the outer side by a plurality of hoops whereby the staves  2  are safely connected to each other. 
     The staves are assembled of individual segments so that a production of the wooden barrels  1  is possible that is efficient and saves raw material. 
       FIGS. 3 to 5  show in an exemplary fashion a stave  2  that is assembled of five segments  2   a  to  2   e . They can have the same but also different lengths. In the illustrated embodiment, the individual segments  2   a  to  2   e  are embodied straight. They are connected to each other with form fit to the stave  2 . The end faces  5 ,  15  with which the segments  2   a  to  2   e  abut each other are angularly configured which will be described in the following with the aid of  FIG. 2 . The segments are pre-planed advantageously at four sides and cut to length. 
       FIG. 2  shows one of the segments that is provided at both end faces  5 ,  15  with a respective form fit element  3 ,  4 . The two form fit elements  3 ,  4  are of complementary configuration and form within the stave  2  a dovetail connection between neighboring segments. 
     The form fit element  3  projects past the end face  5  of the segment  2   b  and has two diverging projections  3   a ,  3   b  with aligned end faces  6 ,  7 . Both projections  3   a ,  3   b  project away from a foot section  8  adjoining the end face  5  of the segment  2   b  whose sidewalls  9 ,  10  pass in opposite direction to each other continuously curved into the end face  5  of the segment  2   b . The transitions of the sidewalls  9 ,  10  to the end face  5  and the end faces  6 ,  7  of the projections  3   a  and  3   b  as well as the projections  3   a ,  3   b  are each provided with radii. 
     The foot section  8  of the form fit element  3  is positioned advantageously at approximately half the thickness  13  of the segment  2   b . The foot section  8  has such a thickness that the segments  2   a  to  2   e  placed next to each other have a sufficiently high strength. 
     The form fit elements  3  extend across the entire width  14  of the segments ( FIG. 4 ). 
     The form fit element  4  which is located at the other end face  15  of the segment  2   b  is formed as a recess which is complementary to the form fit element  3  ( FIG. 2 a   ). For receiving the projections  3   a ,  3   b  the form fit element  4  is provided with correspondingly shaped and arranged recesses  16 ,  17 . In the inserted position, the form fit element  3  is contacting with its outer contour the inner contour of the form fit element  4 . 
     As illustrated in  FIG. 3 , the segments  2   b  to  2   d  have the design as described with the aid of  FIG. 2  and  FIG. 2 a   . The two segments  2   a ,  2   e  at the ends of the stave  2  have only at one end face the projecting form fit element  3  or the form fit element  4  embodied as a recess. In this way, the stave  2  is provided with a closed end face  18 ,  19  at both of its ends. 
     Since the stave  2  is of a curved configuration across its length, the end faces  5 ,  15  of the abutting segments  2   a  to  2   e  are embodied at an angle to the outer side of the segments which will be explained with the aid of  FIG. 2   a.    
     The end face  5  which comprises the form fit element  3  is positioned at a small acute angle α relative to a plane  20  ( FIG. 2 a   ) extending perpendicularly to the top and bottom sides  21 ,  22  of the segment  2   b.    
     The oppositely positioned end face  15  of the segment  2   b  is inclined at the same angle α relative to a plane  20   a  which is extending perpendicularly to the top and bottom sides  21 ,  22  but in opposite direction in comparison to the end face  5 . 
     When the segments  2   a  to  2   e  are joined together to the stave  2 , neighboring segments are positioned at an inclination at the angle α relative to each other. The magnitude of the angle α determines the curvature of the stave  2  that is to be produced from the segments  2   a  to  2   e . This curvature of the stave  2  can be taken from  FIGS. 3 to 5 . In the finished barrel, the curvature of the stave results from the height of the barrel and the dimension of its bulgy shape. In order to produce the raw stave in the length ready for installation and with the curvature ready for installation, the number of the segments and the angle α must be appropriately selected. 
     Since the segments  2   a  to  2   e  each are straight, the stave  2  which is assembled of the segments has a discontinuous shape in the raw state. In order to provide the stave  2  with a continuously curved shape across its length, the stave  2  which is illustrated in the raw state in  FIGS. 3 and 4  is further machined after joining together. 
     Due to the described configuration of the form fit elements  3 ,  4  with the continuously curved contour transitions, neighboring segments can be joined together such that their end faces  5 ,  15  and form fit elements  3 ,  4  are abutting each other flat and a high seal tightness of the form fit connections is ensured. 
     Based on  FIGS. 6 to 9 , machining of the stave  2  in the raw state is described. The machine employed for machining the stave  2  is only schematically illustrated. This machine is a throughfeed machine in which the staves  2  are machined at their sides during their transport through the machine. 
     The staves  2  are resting with a narrow side  23  on a machine table (not illustrated) during their transport through the machine. For feeding the stave  2  through the machine, corresponding feed elements such as feed rollers are provided that load the staves  2  resting on the machine table against the machine table and convey them in feed direction. 
     The machine has in the in-feed region a lower horizontal spindle on which a tool is fixedly seated with which at least one groove  24  is milled into the narrow side  23  ( FIG. 6 ) resting on the machine table. As can be seen in  FIG. 6 , several parallel extending grooves  24  are milled into the narrow side  23  of the stave  2 . In the region of the lower horizontal spindle, the machine table is interrupted so that the tool seated on it can m ill the grooves  24 . 
     In the feed direction behind the lower horizontal spindle, the machine bed of the machine is provided with projecting webs extending in the feed direction which engage the grooves  24  and in this way guide the stave  2  during its passage through the machine. 
       FIG. 8  shows a plan view of the stave  2  that is not yet machined whose longitudinal sides  21 ,  22  which form the top side and the bottom side are processed by a right tool  25  and a left tool  26 . Both tools  25 ,  26  are seated fixedly on vertical spindles which are driven in rotation as the stave  2  is fed through in the feed direction  27 . The grooves  24  extend parallel to the feed direction  27 . 
     The axes of rotation  28 ,  29  of the tools  25 ,  26  as well as their engagement regions at the stave  2  are positioned advantageously in feed direction  27  at a minimal distance behind each other or opposite each other. In this way, a high machining precision is obtained. 
     Both tools  25 ,  26  are profiling tools with which the longitudinal sides  21 ,  22  are milled with the contour that is convex or concave in transverse direction. 
     When the staves  2  are assembled to the wooden barrel  1 , the longitudinal sides  21 ,  22  form the outer side and the inner side of the stave  2 . 
     Both tools  25 ,  26  are adjustable in a controlled manner transverse to the feed direction  27  in an adjusting direction  30 ,  31  so that they can produce the curved shape as the stave  2  is fed through the machine. 
     In this context, in known manner the transport path of the individual stave through the machine is recorded and the tools  25 ,  26  are adjusted by the machine control in accordance with the predetermined curvature in such a way that the staves  2  after processing have the desired continuously curved outer side and inner side. 
     The adjustment movement of the tools  25 ,  26  takes into consideration the thickness  13  of the stave  2  so that only so much material is removed that the stave  2  has a sufficient thickness across its length. 
     As can be seen in  FIG. 6 , the left tool  26  with which the outer contour of the stave  2  is produced is designed such that it has a concavely curved milling region  32 . 
     The right tool  25  with which the inner contour of the stave  2  is produced is correspondingly designed such that it has a convexly curved milling region  33 . 
     The axial length of the tools  25 ,  26  is larger than the width  14  of the stave  2  that is thus machined across the entire width by the two tools  25 ,  26 . 
     As it is fed through the machine, the stave  2  is also machined by a top tool  34  ( FIG. 6 ). With the tool  34 , the narrow side  35  which is oppositely positioned to the narrow side  23  is machined. Since the narrow side  35  is positioned at an angle to the horizontal, the axis of rotation  36  of the tool  34  is also correspondingly arranged at an inclination. 
     The tool  34  is a planning tool that is driven in rotation about its axis  36  and that planes the narrow side  35 . 
     Since the stave  2  is curved across its length, the tool  34  has such an axial length that it can machine the curved narrow side  35  across the length of the stave  2 . In this way, an adjustment of the tool  34  in the direction of its axis of rotation  36  is not required for machining the stave  2 . 
     Advantageously, the tool  34  is located in feed direction  27  behind the two tools  25 ,  26 . For adaptation to staves  2  of different widths, the top tool  34  is adjustable in relation to the machine table on which the stave  2  is supported during its passage through the machine. In addition, the tool  34  for adaptation to different angles of inclination of the narrow side  35 , is also adjustable in regard to its inclination so that the axis of rotation  36  of the tool  34  can be adapted to various angles of inclination of the narrow side  35 . For a desired diameter of the barrel to be produced, the number of required staves is derived from the width of the individual staves and the angle of inclination of the narrow side  35  is derived from the number of the staves. 
     After passage through the machine, the stave  2  is finish-machined by means of the tools  25 ,  26 ,  34  at the inner and outer contours as well as at the narrow side  35 . On a second machine, the narrow side  23  with the grooves  24  is subsequently machined. For this purpose, the partially finish-machined stave  2  is turned such that it is resting with its machined narrow side  35  on the machine bed of the second machine. In contrast to the first machine, this machine bed has no projecting webs. For guiding the stave  2 , a left guide  37  as well as a right stop  38  are provided ( FIGS. 7 and 9 ). The guide  37  extends parallel to the feed direction  27  and is resting on the machine bed. Viewed in feed direction  27 , the stave  2  is contacting this left guide  37  approximately at half the length at the highest point of the convex curvature. 
     The stave  2  is contacting with its two ends the oppositely positioned stop  38 , as can be seen in  FIG. 9 . 
     The stop  38  extends also in feed direction  27  and is inclined such that the stave  2  is contacting it in the region of its end face  18  and near the end face  19 . Since the side of the stave  2  which is facing the stop  38  is concavely curved, the stave  2  is contacting the stop  38  only with its end regions  39 ,  40 . 
     The stop  38  has a larger height than the guide  37  ( FIG. 7 ). 
     It is advantageous when the stop  37  is provided so as to be adjustable transverse to the feed direction  27  at the machine so that it can be adapted to staves  2  that are curved differently. Moreover, it is advantageous when the inclination of the stop  38  can be adjusted for adaptation to different angles of inclination of the narrow side. 
     For machining staves  2  of different widths, it is expedient that the stop  38  has a height that corresponds to the largest width of the stave. 
     The narrow side  23  of the stave  2  comprising the grooves  24  is machined with a tool  41  that is rotatably driven about its axis  42  and preferably is a planning tool with which the narrow side  23  is milled such that the grooves  24  are removed. The axis of rotation  42  of the tool  41  is arranged at an inclination such that the narrow side  23  can be machined with the corresponding angle of inclination. 
     The axial length of the tool  41  is so large that the narrow side  23  can be machined across the entire length of the stave  2  without the tool  41  having to be adjusted. 
     For adaptation to staves  2  with different widths, the tool  41  is advantageously adjustable transverse to the machine table in regard to height. 
     It is additionally advantageous that also the inclination of the tool  41  can be adjusted so that also narrow sides  23  of the staves  2  that are positioned at different inclinations can be machined. 
     The second machine has, like the first machine, feed elements with which the stave  2  can be transported through the machine. The feed elements are advantageously feed rollers which rest, as is known, on the narrow side  23  of the stave  2  and transport it in the feed direction  27  while it is resting on the machine table. The stave  2  in this context is supported in the described manner at the guide  37  and at the stop  38  that are located at oppositely positioned sides of the upright standing stave  2 . Advantageously, the feed rollers are also positioned at an inclination and are adjustable or pivotable in regard to the inclination in correspondence to the angle of inclination of the narrow side so that they are properly resting on the entire narrow side  23 . In this context, it must be taken into consideration that the inclination is different before and after machining by the tool  41 . 
     The finish-machined staves ( FIG. 5 ) are then joined together to the wooden barrel  1  in the known manner. In this context, neighboring staves are positioned with their narrow sides  23 ,  35  abutting each other. For increasing the seal-tightness and simplifying assembly, the narrow sides  23 ,  35  can be provided with form fit elements in order to achieve, for example, a v-shaped tongue and groove connection. In this case, the tools  36 ,  41  that machine the narrow sides  23 ,  35  are no planning tools but profiling tools with which the corresponding form fit elements can be produced across the length of the narrow sides  23 ,  35 . For this situation, the tools  34 ,  41  are adjustable in a controlled manner transverse to the feed direction  27  in the direction of their axis of rotation  36 ,  42  during passage of the stave  2  through the machine in order to provide the corresponding form fit elements across the curved length of the narrow sides  23 ,  35 . 
     For increasing the seal-tightness, the narrow sides  23 ,  35  can be connected by means of glue or the staves can be assembled with intermediate positioning of sealing elements. 
     The production of the wooden barrels  1  by means of the staves  2  saves very much raw material because the staves  2  can be assembled of individual segments  2   a  to  2   e . In this way, remnants can be utilized for producing the staves  2 . The wood remnants that are often produced in wood machining can be used in this manner optimally for producing the staves  2  and thus the wooden barrels  1 . Also, the raw wood can be more effectively utilized because comparatively short pieces can be employed which are of a high quality and without cracks and can be sawed from the raw wood without losses in regard to a beneficial fiber course. In contrast thereto, when using single-piece raw staves only a percentage of the log can be utilized in order to obtain the raw staves in the required quality without cracks and with appropriate fiber course. 
     The end face connection of the segments  2   a  to  2   e  can be performed with and without adhesive agent. 
     Since for the production of the staves  2  remnants or short and sawed raw wood pieces can be employed, the wooden barrel  1  can be produced very cost-efficiently without this being associated with disadvantages in regard to stability or seal-tightness. 
     In an alternative embodiment, the form fit elements  3 ,  4  can also be designed such that a keyhole profile results. Such a design of the form fit elements  3 ,  4  also enables an angled positioning of the segments  2   a  to  2   e  next to each other. 
     A further possibility resides in introducing finger joints into the end faces of the segments  2   a  to  2   e . In this case, abutting segments  2   a  to  2   e  engage each other with their finger joint elements. Such a finger joint connection is then realized by means of an adhesive so that the segments  2   a  to  2   e  abutting each other are fixedly connected to each other. 
     Moreover, also separate connecting elements can be employed as they are used, for example, in the furniture or frame industry, e.g. double dovetail/double wedge. Then, in the individual segments only the corresponding counter shape must be provided as a recess. 
     Machining of the end face form fit elements can be realized with conventional processing methods and machines, for example, double end tenoners, CNC machining centers, mortising and tenoning machines. 
     Since the staves  2  are produced from the segments  2   a  to  2   e  which are placed at an angle against each other and are already machined with the intended curvature, the manufacturing costs of the wooden barrel are further reduced because the work step of shaping the barrel, as it is required in conventional wood barrel manufacture, is obsolete. In particular, breakage of wood is avoided which often occurs during barrel shaping. 
     Barrel shaping is realized in conventional wood barrel manufacture by hammer blows which is correlated with great noise and significant use of force. By eliminating this shaping process by means of hammer blows, occupational safety is significantly increased. 
     Since the raw stave is machined with the tools  25 ,  26 ;  34 ,  41 , the segments  2   a  to  2   e  must not have exactly the same thickness and/or width. With the tools  25 ,  26 ;  34 ,  41  unequal thicknesses and/or widths are eliminated. 
     There is also the possibility to form straight raw staves from the segments. In this case, the end faces  5 ,  15  of the segments  2   a  to  2   e  are positioned perpendicularly to the top and bottom sides  21 ,  22 . The segments  2   a  to  2   e  are positioned aligned with each other one after the other in the assembled state. In this case, the same advantages as have been described above result also with respect to the wood yield. Since the staves are initially straight, they are bent by a shaping process as in the above described process of barrel shaping into the shape that is required for producing the wooden barrel  1 . 
     The straight staves are machined in the known manner in a linear straight throughfeed process. In order to produce the required waisting of the stave, the tools are adjusted in a controlled manner transverse to the feed direction during the throughfeed action. The tools are arranged at an inclination in accordance with the desired inclination of the narrow sides and, as needed, can also be adjusted in a controlled manner in regard to their inclination during the throughfeed action of the stave  2 . 
     The advantage of the use of curved raw staves that already have the assembly-ready curvature, resides also in the described simpler machining. The tools for processing the narrow sides must only be adjusted radially, axially and in regard to the inclination but remain rigid during the passage of the stave through the machine and must not be adjusted in a controlled manner. This significantly reduces the control expenditure and the expenditure for recording the workpiece position during the throughfeed action. Directly after machining, the staves have the planar narrow sides with which they are resting tightly against each other upon assembly of the barrel. 
     For forming the curved raw stave, instead of straight segment pieces which are machined at end faces at an angle and are resting against each other angularly, it is also possible to use segments that are curved in length direction which are joined together at end faces at a right angle but also at a different angle. 
     After assembling the staves  2 , milled slots for a cover can be provided at the upper and/or lower end. 
     For a high quality appearance, the visible outer side of the staves  2  can be ground. 
     It is moreover possible, after or prior to assembly of the staves  2  to the wooden barrel  1 , to char or roast or toast the parts at the inner side by means of a thermal treatment (flame treating, roasting, toasting). This treatment provides advantages in respect to affecting the taste (barrique taste) of a wine which is stored in the wooden barrel  1 . 
     For enhancing the barrique taste, at the inner side of the stave  2  can be provided for surface enlargement slots or perforations. 
     In a different method, for machining the raw staves, the narrow side  23  with the grooves  24  can already be machined in the first machine. It comprises an additional lower spindle on which a planning tool is seated with which the grooves  24  can be removed in the described manner. The spindle is arranged with appropriate inclination. The machine table or the workpiece support is advantageously also inclined in the region behind this lower spindle. Alternatively, the workpieces in the region of this lower spindle can be received by a transport unit by means of which they are transported in the feed direction for machining. 
     In another embodiment, the top and bottom sides  21 ,  22  of the raw stave  2  are machined in the described manner on the first machine. The second machine is designed such that special support elements pick up the curved partially machined or raw stave  2  in an exact position from below and transport them linearly through the second machine. For transportation, the machine is provided with a chain feed action at which the support elements are provided. During this feed action, the staves are machined at their narrow sides  23 ,  35  during the throughfeed action by right and left tools that are arranged at an inclination. The staves  2  can be supplied, for example, by robots and can be removed by robots. In a further embodiment, on the first machine advantageously again the top and bottom sides  21 ,  22  of the staves  2  are machined in the described manner. The second machine has a machine table which has a support for the stave  2  that is curved corresponding to the curvature of the stave  2 . The staves  2  are not transported linearly through the machine but along the machine table that is curved in feed direction. The stave  2  is machined at its narrow sides  23 ,  35  with a left and right tool during its passage. In order to produce the required waisting of the stave, the tools are adjusted in a controlled manner transverse to the feed direction during the throughfeed action. The tools are arranged at an inclination in correspondence to the desired inclination at the narrow sides and, as needed, can also be adjusted in a controlled manner in regard to their inclination during passage of the stave  2  through the second machine. This method, as described, is known in today&#39;s machining of straight staves.