Brief description of the invention

The invention relates to a wood veneer and a process for the manufacture of such a wood veneer.

The prior art

Wood veneer is known and used as covering for wood panels.

Due to economic reasons, producers are obliged to find alternative solutions so as to reduce as much as possible the use of massive or plain wood.

Therefore, it has been proposed to replace plain or massive wood by composite material or support and to cover or associate said material or support with a thin wood layer, preferably fine wood, known as veneer, that is preferably reinforced with one or more reinforcing layers which consist of various material in fibre mat or fibre containing non woven material, such as paper, plastic mat, etc.

Veneer bands are manufactured by placing veneer longitudinal elements or strips the one after the other and/or side by side in the longitudinal direction and by attaching together said veneer elements or strips.

Applicant has tried veneer longitudinal elements or strips or bands or laths with lateral ends (ends perpendicular to the longitudinal direction) provided with sharp- pointed teeth ends, said veneer longitudinal elements being attached together by a PVAC glue. The sharp-pointed teeth of a lateral edge of a first longitudinal lath is placed with interposition of glue between the gaps formed between the sharp pointed teeth of a lateral edge of a second lath edge. The manufacture of such veneer longitudinal elements or strips or bands is expensive and complicated. Furthermore, there is also a problem of stability.

Applicant has now observed that wood veneer with excellent properties can be manufactured by gluing together wood veneer elements without requiring expensive and complicated machines. Furthermore, the wood veneer band has a good stability and mechanical properties at the glued edges.

Applicant has also observed that it was possible to manufacture stable wood veneer structure formed by attaching longitudinally together two or more distinct longitudinal wood veneer bands, whereby facilitating the use of wood veneer for covering large panel, etc. The various longitudinal bands can be attached together substantially simultaneously.

Brief description of the invention

The invention relates to a wood veneer, especially wood veneer band , with a thickness comprised between 0.3 mm and 3 mm, which comprises a series of longitudinal wood veneer elements, said wood veneer elements having two substantially parallel opposite faces extending between two opposite longitudinal edges and two opposite lateral edges.

Preferably at least two opposite edges, extending in a plane or in planes inclined with respect to said substantially parallel opposite faces so as to form inclined

The wood veneer comprises at least a first longitudinal wood veneer element or band, a second longitudinal wood veneer element or band and a third longitudinal wood veneer element or band located between the first and second wood veneer elements or bands, the longitudinal edges, advantageously inclined, of the third longitudinal element or band being respectively attached with a binding means, advantageously glued, to a longitudinal edge, advantageously inclined, of the first longitudinal wood veneer element or band and to a longitudinal edge, advantageously inclined, of the second longitudinal wood veneer element or band, the longitudinal edges of the third wood veneer element or band being advantageously inclined so as to cover or to be covered by respectively an inclined longitudinal edge of the first longitudinal wood veneer element or band and an inclined longitudinal edge of the second longitudinal wood veneer element or band.

According to an embodiment, the wood veneer comprises at least a first series of wood veneer elements attached the one to the other along their longitudinal edge, a second series of wood veneer element attached the one to the other along their longitudinal edge, and at least one wood veneer element (for example a plurality) extending between said first series and second series and having longitudinal edges extending in a longitudinal direction inclined with respect to the longitudinal direction of the longitudinal edges of the wood veneer elements of the first and second series. Said wood veneer element or elements extending between the first and second series are advantageously transversal to the longitudinal direction of the wood veneer elements of the first and second series, i.e. the longitudinal direction of the wood veneer element(s) situated between the first and second series being perpendicular to the longitudinal direction of the wood veneer elements of the first and second series.

According to another embodiment, the wood veneer comprises at least a first series of wood veneer elements attached the one to the other along their longitudinal edge, a second series of wood veneer element attached the one to the other along their longitudinal edge, and at least third series of wood veneer elements attached the one to the other along their longitudinal edges, said third series extending between said first series and second series, whereby the wood veneer elements of the third series have longitudinal edges inclined with respect to the longitudinal edges of the wood veneer elements of the first and second series, and whereby a longitudinal edge of a first wood veneer element of the third series is attached, advantageously glued, to an end of the first series, while a longitudinal edge of a second wood veneer element of the third series is attached, advantageously glued, to an end of the second series.

The wood veneer formed by attaching, advantageously gluing, adjacent veneer elements has advantageously two opposite parallel faces, whereby the inclined edges attached together of two adjacent wood veneer elements extend in a plane forming an angle comprised between 15° and 45°, advantageously between 15 and 30°, preferably about 20° with respect to a plane in which extends one of said two opposite parallel faces.

With respect to the veneer elements, one of the edges, preferably both opposite edges (such as the two longitudinal edges and/or the two lateral edges) extend(s) in a plane or in planes inclined with respect to said substantially parallel opposite faces (upper face and lower face) so as to form inclined edge(s), whereby said inclined edge(s) has a width comprised between 0.2 mm and 30 mm, preferably between 0.5 and 20mm, most preferably between 3mm and 15mm. Two adjacent elements are adapted so that an inclined edge of one element covers at least a portion of an inclined edge of another element, said inclined edges being bound, especially glued together by at least a gluing means, especially a glue layer. A good binding between two adjacent veneer elements glued together can be achieved.

Advantageously, the wood veneer comprises at least a first longitudinal wood veneer element or band, a second longitudinal wood veneer element or band and a third longitudinal wood veneer element or band located between the first and second wood veneer elements or bands, the inclined longitudinal edges of the third longitudinal element or band being respectively glued to an inclined longitudinal edge of the first longitudinal wood veneer element or band and to an inclined longitudinal edge of the second longitudinal wood veneer element or band, the inclined longitudinal edges of the third wood veneer element or band covering or being covered by respectively an inclined longitudinal edge of the first longitudinal wood veneer element and an inclined longitudinal edge of the second longitudinal wood veneer element. Said inclined edges have a width comprised between 0.2 mm and 30 mm, preferably between 0.5 and 20mm, most preferably between 3mm and 15mm.

The wood veneer can comprises a series of 3 to 10 adjacent longitudinal veneer elements or strips or bands for making a wood veneer with a larger width. In the length or in the longitudinal direction, the veneer comprises also a series of veneer elements attached with a binding means, advantageously glued one to another.

Preferably, the wood veneer formed by gluing longitudinal adjacent veneer elements or bands has two opposite parallel faces, whereby the inclined edges (lateral and/or longitudinal) glued together of two adjacent wood veneer elements extend in a plane forming an angle comprised between 10° and 45°, especially between 15° and 30°, preferably about 20°, with respect to a plane in which extends one of said two opposite parallel faces.

According to an embodiment, two inclined edges (lateral and/or longitudinal) of two adjacent wood veneer elements are attached or bound together by means of a binding or glue layer extending between the said two inclined edges, said binding or glue layer extending between the two inclined edges (lateral and/or longitudinal) glued together having with a maximum thickness of 0.5mm, advantageously of 0.3mm, preferably of 0.15mm. It means that the two inclined edges (lateral and/or longitudinal) bound or glued together are distant the one from the other by a distance of less than 0.5mm, such as less than 0.3mm, preferably less than 0.15mm.

According to a preferred embodiment, in which two inclined edges (lateral and/or longitudinal) of two adjacent wood veneer elements are attached together by means of a binding or glue layer, a portion of the binding means or glue extends in the attached wood veneer elements along the inclined edges within a maximum thickness of at least 0.1 mm, preferably at least 0.2 mm, most preferably comprised between 0.2mm and lmm.

Preferably, a portion of the glue extends in the attached wood veneer elements along the inclined edges within a minimum thickness comprised between 0.05mm and 0.1mm.

According to an advantageous embodiment, the glue is a thermoplastic polyurethane (hot melt) containing glue with a melting point comprised between 900C and 170°C, advantageously comprised between 1100C and 150°C, preferably about 130°C.

According to other embodiments, the glue is a PVAC containing glue or an Urea containing glue or a two component glue, such as a glue using a hardening agent.

The invention relates also to a wood veneer element as disclosed above, which has at least one longitudinal and/or lateral inclined edge provided with a glue layer or with a layer comprising a glue component. The thickness of the glue layer is advantageously lower than 0.5mm. The wood veneer element has two substantially parallel opposite faces extending between two opposite longitudinal edges and two opposite lateral edges. One of said edges, preferably two opposite edges (such as the two longitudinal edges and/or the two lateral edges) extend(s) in a plane or in planes inclined with respect to said substantially parallel opposite faces (upper face and lower face) so as to form inclined edge(s), whereby said inclined edge(s) has a width comprised between 0.2 mm and 30 mm, preferably between 0.5 and 20mm, most preferably between 3mm and 15mm.

Preferably, a portion of the glue extends in the attached wood veneer elements along the inclined longitudinal and/or lateral edges within a minimum thickness comprised between 0.05mm and 0.1mm. According to an advantageous embodiment, the binding means or glue is a thermoplastic polyurethane (hot melt) containing glue with a melting point comprised between 90°C and 170°C, advantageously comprised between 110°C and 150°C, preferably about 130°C.

According to other embodiments, the glue is a PVAC (polyvinyl acetate) containing glue or an Urea containing glue or a two component glue, such as a glue using a hardening agent.

The invention further relates to a composite material comprising a support which is at least partly covered by a wood veneer of the invention, said wood veneer being preferably bound or glued on said support.

The invention relates also to a process for the preparation of a wood veneer of the invention.

In an embodiment of said process, a first series of wood veneer elements are attached one after another so as to form a first longitudinal band, while a second series of wood veneer elements are attached one after another so as to form a second longitudinal band, whereby a longitudinal edge of the wood veneer elements forming the first longitudinal band is attached by a binding means, advantageously glued, to a longitudinal edge of wood veneer elements of the second longitudinal band.

Preferably, a first series of wood veneer elements are attached one after another so as to form a first longitudinal band, while a second series of wood veneer elements are attached one after another so as to form a second longitudinal band, whereby an inclined longitudinal edge of the wood veneer elements forming the first longitudinal band is attached, advantageously glued, to an inclined longitudinal edge of wood veneer elements of the second longitudinal band. Most preferably, at least three longitudinal bands (such as 4 to 10 or even more) formed each by a series of wood veneer elements attached, advantageously glued, one to another, are attached one to another along their inclined longitudinal edges.

The binding of wood elements for extending a wood veneer band is preferably carried out just prior to the binding together of two portions of adjacent wood veneer bands. For example, the binding of wood element for extending a band is carried out on a wood element of a band not yet longitudinally bound to a wood veneer element of another band.

In a process of the invention, a longitudinal edge of a wood veneer element forming the first longitudinal band is attached, advantageously glued, to a longitudinal edge of a wood veneer element of the second longitudinal band, said wood veneer elements to be attached together along their longitudinal edge being adjacent to wood veneer elements of the first and second band already attached together along their longitudinal edges.

According to a detail of a process, a longitudinal edge, advantageously inclined, of a wood veneer element is attached to an end, advantageously inclined, of a wood veneer structure formed by attaching longitudinally adjacent wood veneer bands. Advantageously, at least one further wood veneer element is attached to the wood veneer element having its longitudinal edge attached to the end of the wood veneer structure. Said process is suitable for manufacturing longitudinal structure combining first portions formed by a series of longitudinal veneer bands attached one to another, and ρortion(s) formed by veneer wood elements with their longitudinal edges perpendicular to the longitudinal direction of the bands of the first portions. Advantageously, an inclined ((lateral and/or longitudinal) preferably at least longitudinal) edge of a first wood veneer element ( said edge having a width comprised between 0.2 mm and 30 mm, preferably between 0.5 and 20mm, most preferably between 3mm and 15mm) is provided with a binding means or gluing means or a glue component, while an inclined (preferably at least longitudinal) edge (adapted to the inclined edge of the first wood veneer element) of a second wood veneer element is contacted and pushed on the inclined (longitudinal) edge, provided with gluing means or a glue component, so as to form a binding layer or a glue layer extending between the inclined (preferably at least longitudinal) edges with a substantially constant thickness, said thickness measured between the inclined (preferably at least longitudinal) edges being lower than 0.5mm, and so that at least one face of the first wood veneer element and on face of the second wood veneer element extend in a same plane.

Advantageously, the inclined (preferably at least longitudinal) edge of the second wood veneer element is provided with a binding or gluing means or a glue component before being contacted with and pushed on the inclined (preferably longitudinal) edge of the first wood veneer element provided with a binding or gluing means of a glue component.

Preferably, glue or glue component flows, preferably is pushed, in the wood veneer element along the inclined edge on a thickness between 0.05mm and 1 mm, preferably between 0.1 mm and 1 mm.

Most preferably, the glue or glue component is placed on a (preferably longitudinal) inclined edge by means of rotating wheel with respect to a rotation axis. Preferably, a portion of said rotating wheel has the shape of a cone or a truncated cone with a generating line forming an angle comprised between 45° and 80° with respect to the rotation axis, preferably comprised between 60° and 75°, most preferably about 70°. According to an advantageous embodiment, the veneer element which has an inclined edge (lateral and/or longitudinal) to be provided with glue or a glue component, is submitted to a relative movement with respect to the axis of rotation of the rotating wheel, whereby a portion of said inclined edge contacts a portion of the rotating wheel adjacent to a generating line. Preferably, the relative movement is perpendicular to the axis of rotation.

Preferably, the portion of the rotating wheel has the shape of a cone or a truncated cone is provided with at least one groove, advantageously one substantially circular groove. Most preferably, the portion of the rotating wheel has the shape of a cone or a truncated cone is provided with at least two parallel grooves, advantageously two substantially circular grooves. The groove(s) advantageously extend(s) substantially perpendicular to the rotation axis of the wheel. According to an advantageous embodiment, at least one groove is located on the face of the portion with the shape of a cone or a truncated cone intended to contact a portion of the inclined edge (lateral and/or longitudinal) of a veneer element which is adjacent to the end line (lateral and/or longitudinal) which is the most away from the rotating axis.

According to a detail, the portion with the shape of a cone or a truncated cone intended to contact a portion of the inclined edge (lateral and/or longitudinal) of a veneer element has a thickness greater than the thickness of the wood veneer.

According to another advantageous embodiment, the portion with the shape of a cone or a truncated cone intended to contact a portion of the inclined edge (lateral and/or longitudinal) of a veneer element is provided with an anti adhesion layer or covering, advantageously a fluorinated layer or a ceramic layer.

According to another embodiment, the portion with the shape of a cone or a truncated cone intended to contact a portion of the inclined edge (lateral and/or longitudinal) of a veneer element is at least partly manufactured in a fluorine containing material, such as in teflon.

In a specific embodiment, the binding means or glue or glue component flows towards a portion of the groove or grooves through an opening of a channel or duct or chamber.

Advantageously, the channel or duct or chamber forms a closed circuit with a first opening directed towards the veneer element, and with a second opening for the admission of new binding means or glue or glue component in the closed circuit.

Preferably, the binding means or glue or a glue component flows through an opening of a central channel or duct or chamber in the groove or grooves of the rotating wheel in contact with the longitudinal inclined edge of a veneer element to be provided with a binding means or glue or a glue component, while another channel or duct or chamber extends between a first opening in front of a portion of the groove located on the left side with respect to the portion of the groove located in front of the opening of the central channel or duct or chamber, and a second opening in front of a portion of the groove located on the right side with respect to the portion of the groove located in front of the opening of the central channel or duct or chamber. The central channel or duct or chamber has advantageously a volume of less than 500ml, preferably comprised between 5 ml and 400ml, such as between 10 and 300 ml. The central channel or duct or chamber has advantageously a limited volume so as to facilitate the cleaning of the central channel or duct or chamber. The central channel or duct or chamber is advantageously provided with control means, for example for determining the quantity of binding means or glue or glue component present in the channel or duct or chamber. Such a means is for example a membrane. The glue is advantageously selected from the group consisting of thermoplastic glue, PVAC glue, urea containing glue, UV curing resin and two components glue. Thermoplastic polyurethane is preferred.

The binding means or glue or a glue component is advantageously heated before being applied on an inclined edge, so as to apply heated glue or heated glue component on said inclined edge. For example, the heating is such that the binding means or glue or the glue component is applied at a temperature comprised between 90°C and 15O0C.

According to a specific embodiment, the process is a process in which a two component glue is used for gluing an inclined edge (lateral and/or longitudinal) of a first veneer element with an inclined edge (lateral and/or longitudinal) of a second veneer element, whereby a first glue component is placed on the inclined edge of the first veneer element to be glued by means of any rotating wheel as disclosed above, while a second glue component is placed on the inclined edge of the second veneer element to be glued by means of any rotating wheel as disclosed above , and in which the inclined edge of the first veneer element provided with the first glue component is pushed on the inclined edge of the second veneer element provided with the second glue component, so that the first and second glue components are contacting each other so as to harden and to form a binding (lateral and/or longitudinal) of the two veneer elements.

According to a detail of an embodiment of the process, the veneer elements are sawn in the length and/or in the width from a wood piece so as to form two opposite (lateral and/or longitudinal) inclined edges, while a binding means or glue or a glue component is placed on a first inclined edge before forming the second inclined edge and/or during the sawing of the first and/or second inclined edge and/or after the sawing of the first and/or second edges. The invention further relates to - a device for manufacturing a wood veneer, especially according to the process of the invention, said device having as improvement a rotating wheel for bringing a binding means or a glue or a glue component on an inclined edge of a veneer element as disclosed above in the specification, and - a head adapted for applying a binding means or a glue or a glue component on a longitudinal inclined edge of a veneer element, advantageously according to a process of the invention, whereby said head has a rotating wheel for bringing binding means or a glue or a glue component on an inclined edge of a veneer element as disclosed above in the specification.

Details and characteristics of the invention will appear from the following description, in which reference is made to the attached drawings.

Brief description of the drawings

In the drawings, - figure 1 is a view in perspective of a veneer element ; - figure 2 is a cross section view along the line II-II (longitudinal direction) of the veneer element of figure 1 ; - figure 3 is a partial side view of a veneer ; - figure 4 is a view in perspective of a gluing head ; - figure 5 is a cross section view along the line V-V of the gluing head of figure 4 ; - figure 6 is a cross section view of the gluing wheel ; - figure 7 is a cross section view of the gluing wheel in contact with an inclined edge of a veneer element ; - figure 8 is a cross section view along the line VIII-VIII of the gluing head of figure 4 ; - figures 9 to 11 are cross section views respectively along the lines IX-IX, X-X and XI-XI of the gluing head of figure 8 , - figure 12 is a schematic view of a process of the invention, figure 13 is a schematic perspective view of a wood veneer structure of the invention.

Description of preferred embodiments

Figure 1 shows a longitudinal veneer element or lath 1 with a upper face 2, a lower face 3 parallel to the upper face 2, two longitudinal edges 8,8, and two inclined lateral end edges 4,5. The thickness E of the wood veneer element or lath 1 is for example comprised between 0.3 mm and 3 mm, such as about 0.5 mm. The inclined lateral end edges extend each in a plane forming an angle α of about 20° with the plane in which extends the upper face 2 or the lower face 3. The end inclined faces 4,5 are parallel to each other. The width BB of the inclined edges 4,5 varies from the thickness of the lath 1 and of the angle α. For an angle of 20° and a thickness of 0.5mm, the width BB is equal to about 1.38mm (0.5 mm x cotangent 20°).

The inclined face or edge 4 is provided with a glue layer 6 or a layer containing a glue component, when using a two component glue. Preferably, the glue layer is a thermoplastic polyurethane layer. The polyurethane has advantageously a melting point of about 130°C. A portion of the glue flows or penetrates in the wood veneer element along the inclined edge 4.

The thickness of the glue layer 6 covering the inclined edge 4 is for example about 0.25 mm, while some glue penetrates in the wood veneer element on a thickness E2 of about 0.1 mm to 0.2 mm along the face 4.

In the embodiment shown, the longitudinal edge are perpendicular to the upper face 2. However, in a preferred form said longitudinal edges are also inclined with respect to the plane in which the face 2 extends. This enables thus to bind longitudinally adjacent veneer elements. The veneer element is for example made of fine wood, such as fine and tough wood, such as oak, teck, Brazilian rose wood, etc.

In another preferred embodiment, the two opposite edges 4,5 are provided with a glue layer as binding means for attaching said wood veneer element to another wood veneer element.

Still in another embodiment the two lateral edges and the two longitudinal edges are inclined and provided with a glue layer.

In order to manufacture a veneer band 10, a plurality of veneer elements or laths 1 of figure 1 are glued together so that one inclined end edge 4 of a veneer element is bound by the glue layer 6 to the inclined edge 5 of another veneer element or lath. The inclined end edge 4 of a veneer lath covers substantially completely the inclined end edge 5 of the adjacent veneer lath. The upper faces of the adjacent laths 1 glued together extend substantially in a same plane. The lower faces of the adjacent laths 1 glued together extend substantially in a same plane.

The gluing operation of the inclined edges of two adjacent veneer laths is made with the glue or the glue mixture applied on one or both inclined edges before its hardening. Said operation is advantageously operated while pushing one inclined edge on the edge to be glued. A pressure is advantageously maintained during the at least partial hardening of the glue.

In an embodiment, the longitudinal edges of the bands to be bound together are not inclined.

When using thermoplastic glue, especially thermoplastic polyurethane, the inclined edges of the veneer elements to be glued together are contacted when the glue applied on one or both inclined edges is still sufficiently fluid or liquid or with a reduced viscosity. For example, the edges to be glued together are contacted when the temperature of the glue applied on the edge or edges is higher than 50°C, advantageously comprised between 50°C and 90°C, such as 55°C, 60°C, 70°C, 80°C, 90°C. A pressure is advantageously exerted up to the substantially complete hardening of the glue.

A glue layer 11 (for example a polyurethane layer) is formed between the inclined edges of two adjacent veneer laths 1. Said layer has a thickness EE for example of about 0.15 to 0.25 mm, as some glue is flowing in the veneer lath, the inclined edge 5 of which was not provided with a glue layer prior to be contacted with the inclined edge 4 covered with glue. Glue flows thus into the veneer lath along the inclined face 5. (see figure 3)

In order to obtain wood veneer having a sufficient width or greater width, veneer bands can be longitudinally glued together (preferably by means a thermoplastic glue, such as a thermoplastic polyurethane. When using thermoplastic glue, the temperature of the glue is preferably comprised between 60°C and 80°C ). The longitudinal edges of the veneer laths or bands are advantageously inclined. The veneer laths are thus glued the one to the other, the one after the other or side by side.

Figure 4 shows a gluing head 20 adapted for covering an inclined edge 4 of a veneer lath 1 or element with a glue layer or a layer containing a glue component of a two component glue. The gluing head comprises : - a means for pushing or feeding glue or a glue component (preferably liquid or with low viscosity) in an inner chamber 21 ; - a central channel 22 with a volume lower than 500ml for conducting the glue or glue component towards a coating wheel 23 ; - a driving means 24 for rotating the coating wheel 23 around its axis ; - a supporting means 25 for the veneer element or lath, said means being adapted for ensuring a correct position of the veneer element or lath with respect to the coating wheel 23, and - possibly a means for heating the glue or the glue component, so as to reduce its viscosity or so as to render it substantially liquid (heating up to a temperature above the melting point of the glue, for example when using thermoplastic polyurethane glue).

The veneer lath or element 1 is moved in front of the head 20 (in the direction of the arrow X) so that the inclined edge ( for example 4) is provided on its complete face (from the upper edge line (4A) up to the lower edge line (4B)) with a glue layer 6 or a glue component layer (such as for example a thermoplastic polyurethane layer). The wheel 23 rotates around its axis 23A in the direction of the arrow R. The radial speed of the wheel determined for the portion in contact with the inclined edge to be provided with a glue layer corresponds substantially to the speed of the movement of the veneer lath or element 1 (arrow X).

The wheel 23 is for example at least partly in Teflon ® and has a portion having the shape of a truncated cone defined by a generating line forming an angle β of about 70° (angle measured between a generating line of the outer surface of the truncated cone and the rotating axis A-A, see figure 6). The outer Teflon layer can advantageously be replaced by a ceramic coating or layer. The basis material of the wheel is for example stainless steel.

The rotating axis A-A of the wheel 23 is advantageously substantially vertical, while the wood veneer lath or element 1 is moved in a substantially horizontal plane.

The wheel 23 is placed so that the cone or truncate cone is directed upwardly (the top of the cone is directed upwardly with respect to the basis). The outer face 23B of the portion of the wheel 23 with the shape of a truncated cone is provided with two parallel grooves 23C,23D, said grooves having a width of less than 2mm, such as from 0.5mm to 1.5mm. The depth of the grooves is lower than 0.8 mm, preferably lower than 0.5mm. The depth of the groove 23D is advantageously lower than the depth of the groove 23C. The groove 23D is located on a portion of the outer surface of the truncated cone 23B which is defined with a diameter D23d which is greater than the diameter D23c defining the portion of the outer surface of the truncated cone 23B where the groove 23C is located.

The grooves are substantially perpendicular to the rotation axis A-A.

The grooves 23C,23D are adjacent to each other, the distance separating the grooves from each other is lower than lmm, preferably lower than 0.5mm. The grooves are located on a portion 23B of the wheel 23 with the shape of a truncated cone adapted for contacting the portion of the inclined edge which is the more distant from the axis A-A. For the inclined edge 4, said portion is a portion adjacent to the lower edge line 4B.

The portion of the wheel 23 with the shape of a truncated cone which is adapted to contact the inclined edge has for example a minimum diameter of 20 mm, preferably of 25mm, and a maximum diameter lower than 40mm, preferably lower than 30mm.

The head 20 is also provided with an inner channel or duct 27 which extends between two portions D1,D2 of the wheel 23 and of the grooves 23C,23D, whereby said portions are distant from the portion C of the wheel in front of the opening of the central channel 22, and whereby said portions are located on both sides of the portion C (portion Dl located right with respect to portion C or the opening of the central channel, while portion D2 is located left with respect to portion D or the opening of the central channel. Such a head 20 is advantageous for achieving a god filling of the grooves 23C,23D with glue or glue component, for example with thermoplastic polyurethane, and thus for achieving the coating of the inclined edge with a glue layer having a substantially constant thickness.

For controlling the thickness of the glue layer on the rotating wheel 23, an element or a cutter 30 can be provided. The element or cutter 30 is advantageously movable with respect to the wheel 23 so as to enable a correct positioning of the element 30 with respect to the wheel 23. For example, the edges of the element or cutter 30 moves respectively in a lower groove and in an upper groove of the head.

The element 30 and the element 31 (used for avoiding glue to flow outside in a direction opposite to the direction of rotation of the wheel) extend between the plates P1,P2 of the head and act as means for closing the opening formed between the plates and the wheel.

The head 20 is also provided with a means for 21 determining the glue content (for example the thermoplastic polyurethane content) in the central channel 22, for example for determining whether glue needs to be fed in the channel 22. The means 21 is for example a membrane.

Figure 12 is schematic view of a system for manufacturing a veneer formed by gluing together two veneer bands FB1,FB2 along their adjacent longitudinal edges, preferably inclined edges.

The system or installation comprises : - a sawing station 40 adapted for cutting irregular or uneven wood layer in wood veneer with at least an inclined lateral edge for gluing laths together the one after the other for making bands and at least one inclined longitudinal edge for gluing side by side adjacent laths or bands, whereby said sawing station comprises at least a cutting means which are inclined so as to form the required edges, such as the inclined edges. The arrows Feeding show possible directions of movement of the wood layer towards the saw station (for lateral feeding and/or front feeding). - a gluing station 41 for coating at least a lateral inclined edge of the laths with a glue layer or a layer comprising a glue component. For example, the lateral inclined edge 4 of the lath is provided with a glue layer. Said gluing station is suitable for applying glue on an inclined edge of wood veneer elements intended to be used in the first band as well as in the second band and even the third band. - a station 42 for placing the cut lath provided with a glue layer on its lateral edge after another lath already bound by a glue layer to still another lath, and for binding the cut lath with said another lath, the station is adapted for making two or more than two (such as 3, 4, 5 and even more) veneer bands FB1,FB2, FB3, etc. formed by laths bound the one to the other along their lateral edges. The station 42 has advantageously a means for exerting a pressure during the gluing of the lateral edges of two adjacent laths, said station or means being advantageously provided with a cooling system so as to cool the hot melt glue (such as thermoplastic polyurethane glue) or with a heating system for accelerating the curing or the hardening of the glue. - a sawing station 43 for cutting the free lateral edge of the already formed band or bands so as to form an inclined edge adapted with shape of the lateral inclined edge formed in the sawing station 40, - possibly a sawing station for cutting the longitudinal edge of the band or bands. When two bands or more have to be glued side by side, the sawing station has advantageously cutting means adapted for forming inclined longitudinal edges so that when a first band contact a second band, an inclined longitudinal edge of one band is covered by the longitudinal edge of the other band. - a gluing station 44 for providing glue on the longitudinal edge 9 of the veneer band FBI, while the veneer band FB2 is moved above the gluing station 44. When the longitudinal edge is upright, the station comprises for example a common roller, while when the longitudinal edge is inclined, a gluing head as disclosed in figure 4 is advantageously used. The membrane 21 is then advantageously placed on the back or a side face of the gluing head. When three longitudinal band are to be glued one to another, the device comprises advantageously a gluing station 44 bis adjacent to the gluing station 44, said gluing station 44 bis being adapted for applying a glue layer on a longitudinal edge of the wood veneer band FB3. - a station for gluing or binding together the veneer bands FBI and FB2 along their adjacent longitudinal edges. Said station is advantageously provided with a means for exerting a pressure between the veneer band to be glued together and with a cooling system so as to cool the hot melt glue (such as thermoplastic polyurethane glue) or with a system for accelerating the curing or the hardening of the glue, such as a heating system or a system emitting rays, such UV rays. - a station for winding the veneer bands glued together.

When transversal veneer elements have to be attached to an end of the formed longitudinal veneer structure consisting in this example of two or three veneer bands, veneer elements are fed in the other direction (Feeding 1) whereby enabling one longitudinal edges to be cut with the appropriate angle in the sawing station 40, said longitudinal edge being then provided with glue in the gluing station 41. The wood veneer element is then glued on the end of the structure, the free end of the structure being then formed by the other longitudinal edge of wood veneer element. Said other longitudinal edge is then cut or shaped so as to have the appropriate angle for enabling the binding with another wood veneer element (transversal with respect to the longitudinal direction LD ) or with wood veneer elements (longitudinal). When transversal veneer elements have to be attached to the end of the structure, the gluing head 44, 44bis are for example moved away.

Figure 13 is a schematic view of a veneer structure which can be produced with the machine of figure 12.

The wood structure of figure 13 comprises various portions, namely : - a first portion 100 comprising four longitudinal bands FBI, FB2,FB3,FB4 of wood veneer elements 1 , the wood veneer elements of each band being connected one to another by a glue layer connecting lateral inclined edges 4, while the longitudinal edges 9 are advantageously also inclined so as to have a better longitudinal binding of the wood elements of different bands, - a portion 101 comprising wood veneer elements 1 extending in a direction perpendicular to the longitudinal direction LD of the bands FB1,FB2, ..., the longitudinal edge 9 of a wood veneer element 1 being inclined and glued on the the lateral inclined edges 4 of the wood veneer elements of the four bands. - a portion 102 similar to the portion 100 and attached to the portion 101 as the portion 100 is attached to the portion 101.

This system or installation can also be used for forming a plurality of independent veneer bands, when the veneer bands are not glued together.

The system can also be further provided with means for removing quickly the humidity or solvent from the glue layer. This can be done by using a means exerting a pressure along the place of the edges to be glued together, and /or by using a means for drawing humidity or solvent. The means for exerting a pressure is for example a pressing bloc or head provided with openings or channels or grooves associated to a means for drawing gases.

In the gluing head of figure 4, the lateral and longitudinal edges of the veneer laths are advantageously cut, so as to be able to correctly control the movement of the lath during the coating of an inclined edge with glue or glue component. When using other mechanism for controlling the movement, such as control mechanism using a laser, transport bands between which the veneer lath is pressed, the transport bands controlling the movement of the lath, it is possible to only cut the inclined edge to be provided with glue. The cutting of the other edges can be done after the gluing of the inclined edges of two adjacent veneer lath.

When using a two component glue, a first component is for example used for coating an inclined edge, while the second component is thereafter sprayed on the coating prior to the contacting of said inclined edge with another inclined edge or sprayed on the other inclined edge before being contacted with the inclined edge provided with the coating.

According to an embodiment the gluing together of two inclined edges is achieved by using a glue strip, said strip having glue on its both opposite faces and is advantageously provided with a net of fibres, woven fabric, non woven fabric, etc.