GB2236708A

GB2236708A - Production of artificial briar veneer by parallely grained sheets

Info

Publication number: GB2236708A
Application number: GB9020920A
Authority: GB
Inventors: Giovanna Senzani
Original assignee: Alpi SpA
Current assignee: Alpi SpA
Priority date: 1989-09-29
Filing date: 1990-09-26
Publication date: 1991-04-17
Also published as: IT1231127B; IT8921894A0; JPH03126502A; KR910005982A; GB9020920D0

Abstract

In a method for the production of briar veneer, superimposed and glued sheets 13 of natural wood obtained by rotary cutting a log and parallely grained sheets 19 obtained separately are compressed between the moulds 21, 22 of a press having matching protrusions and cavities to obtain a shaped block 20 having burrs imitating a briar pattern; and from said shaped block of wood an artificial briar veneer 26 is then sliced. The parallely grained sheets 19 are obtained by slicing a block 17 of laminated natural wood sheets. <IMAGE>

Description

"PRODUCTION OF ARTIFICIAL BRIAR VENEER BY PARALLELY GRAINED SHEETS" This invention relates to the production of an artificial briar veneer, and more particularly is aimed at a method for producing briar veneer starting from sheets of natural wood obtained by rotary cutting a log.

Various methods are known for obtaining a veneer of artificial wood and more particularly sheets of veneer having burrs or a briar pattern.

The traditional method normally involve forming a block of wood by sheets of natural woods obtained by rotary cutting a log. which are dyed, glued and compressed between the moulds of a press having protrusions and raised portions imitating a briar pattern; from this shaped block, sheets of veneer as final product are then sliced along a predetermined cutting plane.

In order to obtain the characteristic burr grains of a briar pattern, in addition to the particular configuration of the surfaces of the moulds, the sheets of natural wood must be previously immersed in a dye-bath to enable a colouring substance to penetrate the thickness of the wood. The result obtained is a sheet of veneer in which the grains of the briar is mainly determined by the contrast in colour of the dyed wood, as well as the irregular shape of the lines of the pattern due to the deformations of the sheets of the block disposed between the moulds of the press.

The veneer obtained in this way clearly shows its artificial nature, mostly due to the absence of a fibre structure which imitates or similar to the real grain of a briar veneer in natural wood.

This is due to the fact that in forming the block of wood, the sheets of natural wood obtained by rotary cutting a log have a uniform appearance with the fibres substantially oriented in one same direction and lying in substantially parallel planes.

In this way it is impossible to imitate or form areas having different degree of porosity, correspondingly to a briar veneer in natural wood.

An object of this invention is therefore to provide a method for the production of a veneer of artificial briar aiming to imitate a veneer of natural walnut, in which besides imitating more naturally the grain of any kind of briar it is also possible to imitate different fibre structures of wood, with areas of greater or lesser porosity, that is to say areas which are compact to a greater or lesser extent. In this way the veneer is improved in appearance, as a final product, since the different degree of porosity allows different absorption of the varnish, thus providing a veneer of artificial briar having an appearance similar to a natural veneer.

The above can be achieved with a method according to the invention on the basis of which sheets of natural wood, obtained by rotary cutting a log, are dyed, glued and compressed to form a first block of wood from which sheets of wood having parallel grains are then cut. characterised in that a second block of wood is formed by combining and glueing sheets of natural wood obtained by rotary cutting the log, with sheets of parallely grained wood obtained from the first block of wood shaping said second block between the moulds of a press having protrusions and raised parts imitating a briar pattern, and cutting sheets of veneer having a briar pattern from said second block.

The sheets of natural wood for forming both the first and second blocks, are suitably dyed for example by immersion in a dye-bath in which they are kept for a suitable length of time to cause at least a partial penetration of the colouring agent in the thickness of the wood; nevertheless, as an alternative to or in combination with the referred colouring method by immersion in a dye-bath, the colouring agent could also be applied during the glueing phase by means of the glue itself.

The sheets of parallely grained wood and the sheets of natural wood obtained through rotary cutting a log, may have any thickness desired; similarly the grained sheets which can be obtained from the first block may have longitudinal stripes or grains of variable or predetermined width. Consequently. by means of a suitable choice of sheets and by control of the production process or of the formation of the blocks, artificial briar veneers can be produced in an extremely precise and controlled manner.

The method for producing a briar veneer according to the invention will be illustrated in greater detail hereunder with reference to the accompanying drawings in which: Figure 1 is a diagram illustrating the entire production method.

Figure 2 is a detail illustrating a briar pattern obtained according to the invention.

Reference-10 in Figure 1 denotes a log which is continually sliced by rotary cutting a strip 11 from which sheets of natural wood 13 are then cut by means of a blade 12.

The sheets of natural wood obtained in this way are immersed in a dye-bath 14 in which they are kept for a sufficient length of time to enable at least partial penetration of the colouring agent in the thickness of the sheets. The sheets 13 removed from the dye-bath 14 are passed through a drying oven 15, then spread in 16 on one or both faces with an adhesive agent to form a first block of wood 17 which is adequately compressed between the plates of a press 18.

The block 17, after having been removed from the press 18, is sliced a cutting plane which is slanted or intersects the planes of the sheets of natural wood 13 so as to obtain sheets of wood 19 having striped pattern, in which the grains extend parallely in a direction which is substantially longitudinal to the sheet itself.

A second block of wood 20 is then formed by spreading with glue and superimposing, alternatively or according to a predetermined order, sheets of natural wood 13 having already undergone the dyeing treatment, and sheets of parallely grained wood 19 so as to obtain a composite block of sheets 20 which is placed and shaped between the moulds 21 and 22 of a press 23 in which moulds 21 and 22 have protrusions and raised parts to imitate a briar pattern.

The second block of wood 20 once it has been deformed or shaped in the press 20, is sliced in 24 along a predetermined cutting plane, obtaining veneer sheets 26 with a briar pattern which once dried in a continuous dryer 25, form the final product.

Given that during the formation of the second block of wood 20, sheets of natural wood 13 whose fibres are similarly oriented in the same direction in a plane, are superimposed alternately or according to a predetermined order, with grained sheets 19 obtained by cutting a previous block of sheets of natural wood, these second grained sheets have the fibres oriented in a direction perpendicular to the plane of the sheet in natural wood.

Therefore, as schematically represented in Figure 2, the final veneer sheet may have areas 26b with fibres oriented differently, imitating a different porosity or compactness which is the characteristic of a natural wood veneer; this different porosity is due to the different orientation of the wood fibres in the alternation or set of sheets which compose the block 20; more precisely in Figure 2, the more porous and less compact parts of the veneer sheet correspond to the areas 26a and are due to the orientation of the fibres in the parallely grained sheets which compose the block 20; correspondingly the less porous and more compact parts 26b are due to the orientation of the fibres in the sheets of natural wood which compose the same block of wood 20 mentioned previously.

In this way an artificial veneer having an improved briar pattern is obtained, whose aesthetic appearance is further improved after the varnishing phase as a result of the different degree of absorption of the varnish by the areas 26a imitating a more porous structure in relation to the more compact areas 26b.

From what has been said and shown in the accompanying drawings, it is therefore clear that a method is provided for the production of an artificial briar veneer by means of a suitable combination of sheets of natural wood, formed by rotary cutting a log, and sheets of striped or parallely grained wood formed from a block obtained by combining sheets of natural wood suitably coloured or treated in a dyebath. Therefore what has been said and shown with reference to the accompanying drawings has been give purely by way of an example of the method according to the invention, and that other modifications or variants are possible within the innovative principles set out.

Claims

1. Method for producing sheets of artificial wood veneer imitating a natural briar veneer, whereby sheets of natural wood obtained by rotary cutting a log are dyed, glued and compressed to form a first block comprising the following steps: - preparing basic sheets of natural wood having a homogeneus structure and a first degree of porosity; - forming a first block of wood by overlapping said basic sheets of natural wood provided with an adhesive substance making the sheets adhere to one another by exerting a pressure on the block; - preparing second sheets of wood having parallel grains slicing said sheets from said first block in a direction parallel to a cutting plane; - forming a second block of wood by overlapping said basic sheets and said second sheets of wood suitably provided with an adhesive substance; ; - pressing and shaping said second block in a press comprising mould having irregular matching protrusions and cavities imitating a briar; and slicing veneer sheets having briar patterns from said second block in a direction parallel to a preestablished cutting plane.

2. Method according to claim 1, in which said basic sheets of natural wood for forming both the first and the second blocks, are previously coloured.

3. Method according to claim 1, in which the basic sheets of natural wood and the grained sheets forming said second block, have fibres oriented in parallel planes and arranged in perpendicular direction respectively.

4. A sheet of veneer imitating a natural briar veneer obtained according to the method of the previous claims 1 to 3 and as thereinbefore described with reference to and as illustrated in the accompanying drawings.