EP3365147A1

EP3365147A1 - Method for beveling veneers

Info

Publication number: EP3365147A1
Application number: EP16782068.7A
Authority: EP
Inventors: Josef Hanses
Original assignee: Hanses Sagewerkstechnik & Co KG GmbH
Current assignee: Hanses Sagewerkstechnik & Co KG GmbH
Priority date: 2015-10-21
Filing date: 2016-10-17
Publication date: 2018-08-29
Also published as: CA3001769A1; WO2017067889A1; US20180304491A1; DE102015117931A1

Abstract

The invention relates to a method for beveling veneers (14), characterized in that an edge (26) of the veneer (14) is pressed by a pressure shoe (44) extending along said edge against a base (22) in such a way that the edge projects over the base and in that a trimming device (28) and a grinding tool (30), which has a grinding surface set at an angle to the plane of the veneer, move along the edge (26) of the veneer, such that an edge strip (50) of the veneer is cut off by the trimming device (28) and the veneer is beveled by means of the the grinding head (30).

Description

PROCESS FOR SHARING OF VENEERS

The invention relates to a method for shearing veneers. In the production of laminated veneer lumber, rectangular veneer sheets are laid on top of each other in several layers and glued together under pressure. In a process referred to as book laying, the veneer sheets are folded together to form an endless strand, with the joints between the veneer sheets following one another in the direction of one another being offset from one another in relation to one another, resulting in a stable bond.

To further increase the strength, it is common practice to skew the veneer sheets into shafts at the transverse edges of the strand, ie, to provide a wedge-shaped profile when viewed in the cross-strand direction. The edges of the adjoining veneer boards can be overlapped, so that the superimposed wedge profiles of the two boards complement each other to the full veneer thickness. Saws or milling tools are usually used for the shanks of the veneers. One distinguishes between dry stems and wet stems. In the case of dry stems, the stakes are only milled after the veneers have passed through a dryer. However, since the wood is then relatively hard, it comes with sawing or 5 milling easily cracks and eruptions in the wedge-shaped leaking veneer edges, which is particularly undesirable in the top layers, so the top and bottom veneer layer of veneer lumber, as the irregularly busy edges visible on the finished product.

DE 887 702 C discloses a wet-shearing method in which the shank already takes place during the peeling of the veneers, that is to say in a state in which the wood is still relatively moist and soft. Even with this method, however, you will not get perfectly flawless edges.

The object of the invention is to provide a method which makes it possible to obtain veneer edges of higher quality.

This object is achieved in that one edge of the veneer is pressed with a longitudinally extending edge of this pressure shoe against a pad 20 that the edge projects beyond the base, and that a Besäumvorrichtung and a grinding tool, an oblique to the plane of the veneer has an inclined surface, along the edge of the veneer, so that with the trimming device an edge strip of the veneer is removed and the veneer is handled with the sanding head.

OK

With the grinding tool, the veneer edge can be processed gently, so that the formation of cracks and breakouts is significantly reduced. In addition, with the trimming device, for example a scoring saw or a chipper, a straight cut is made at the tapered end of the cladding zone, so that a straight cut is achieved. de and clean bump. This not only improves the visual appearance, but also facilitates the detection of the edge with an electronic measuring system (camera, light curtain or scanner), so that the book laying process can be controlled more precisely and a higher level of accuracy can be achieved.

Advantageous embodiments and further developments of the invention are specified in the subclaims.

When the trimming device and the grinding tool travel along the veneer edge, the grinding tool preferably follows the trimming device. Since then the edge strip that has been cut or machined with the trimming, does not need to be ground with, results in less wear of the grinding tool and it allows a higher processing speed. The adjustment of the trimming device and of the grinding tool can be carried out so that the veneer thickness at the edge created by the trimming device is reduced to zero with the grinding tool, so that the bearing zone runs at an acute angle. However, it is also a setting possible in which a blunt abutment edge remains, but the thickness is so small that it does not interfere after book laying in appearance. On the other hand, this impact edge increases the resistance of the veneer to impacts and other mechanical effects and reduces the sensitivity to variations in the depth of sanding so that a very clean and straight edge is obtained. The process is preferably carried out as a dry-process after drying the veneers. The invention also provides an apparatus for carrying out the method described above and a method for producing laminated veneer lumber, which is based on the method described above.

In an advantageous embodiment, the proposed here Schäftungs method is only applied to the veneer sheets that are to form the top layers of veneer plywood. The inner veneer layers, where the chipped edges are not visible in the finished product, can already be processed by peeling the veneer in a wet process.

10

It is also possible to use the wet-grinding method for all veneers and then to post-refine the veneers which are to form the cover layers with the dry-method according to the invention. Since in the case a certain slope was already produced at the veneer edge during wet shaving, less material has to be removed with the grinding tool 15, so that the processing speed and the service life of the grinding tool can be increased.

A consequence of this method, however, is that the post-veneered veneers for the cover layers have a shorter length than the veneers for the inner layers. However, this can be accommodated by the fact that the book laying for the topsheets is to some extent asynchronous, that is, with a different rhythm than when laying the inner layers.

In the following an embodiment will be explained in more detail with reference to the drawing.

OK

Show it:

Fig. 1 is a perspective view of the essential parts of a device for shearing veneers according to the method of the invention; FIG. 2 shows a side view of the device from the direction of the arrows II-II in FIG.

Fig. 3 is a view corresponding to Fig. 2, but with a grinding tool of the device omitted, so that a scoring saw disposed behind it is more clearly visible;

Fig. 4 is a perspective view of a veneered edge; and Fig. 5 is a side view of a portion of a multi-ply veneer strand for the production of veneer plywood.

FIG. 1 shows a shed device 10 which is arranged at the end of a belt conveyor 12. On the belt conveyor 12 rectangular veneer sheets 14 are transported, which were previously dried in a drying station, not shown, and sorted in a also not shown sorting station by quality. The shaving apparatus 10 are supplied only those veneer sheets 14, which are largely free of defects and have such a high quality that they are suitable as cover layers of veneer lumber.

The shifter 10 has a rail-like frame 16, which extends at the end of the belt conveyor 12 transversely to the conveying direction over the entire width of the belt conveyor. A carriage 18 is guided on rails 20 and can be moved along the frame 16.

An upper profile region of the frame 16 forms a base 22, which is flush with the top of the belt conveyor 12. In the example shown, a camera 24 is arranged above the belt conveyor 12, with which the time of passage of a leading edge 26 of the veneer panel 14 can be detected. The drive of the belt conveyor 12 is then controlled so that the veneer panel 14 is slid over the end of the belt conveyor onto the base 22 until its leading edge 26 projects slightly beyond the base 22.

On the carriage 18, a trimming device 28 and a grinding tool 30 are arranged.

The trimming device 28 is in the example shown a scoring saw with a circular saw blade 32 which is driven via a belt drive 34 by a rotationally driven drive pulley 36. Optionally, as a trimming and a Zerspaner be provided which completely machined the cut strip of material. The grinding tool 30 has an endless abrasive belt 38 which passes over a belt roll 40 and a corresponding cylindrical portion 42 of the drive pulley 36.

In a starting position, the carriage 18 is located in an end portion of the frame 16, which lies outside the width of the belt conveyor 12 at the left in Fig. 1, so that the trimming device and the grinding tool, the feed of the veneer board 14 are not in the way. After the veneer sheet has been advanced to the desired position, a pressure shoe 44 extending parallel to the backing 22 is lowered by pneumatic, hydraulic, or electric drives 46 so as to press the edge zone of the veneer sheet 14 against the backing 22 so to fix the veneer board. Subsequently, the carriage 18 moves from left to right in Fig. 1, so that with the circular saw blade 32, a narrow edge strip is cut from the protruding part of the veneer panel 14 and then with the grinding tool 30, the underside of the veneer board is ground at an angle to the veneer board the edge 26 to shafts. Subsequently, the pressure shoe 44 is raised again, the veneer panel 14 is moved back slightly with the belt conveyor 12 and then lifted with a suction harness, not shown, and converted to a laying line on which a multi-ply strand 5 is laid by veneer panels, as will be described in more detail later ,

In Fig. 2 it can be seen that the axis of the tape roll 40 for the abrasive belt 38 as well as the axis of the circular saw blade 32, which is almost completely obscured in Fig. 2, with respect to the plane of the veneer panel 14 are made somewhat oblique such that the abrasive tool produces a wedge-shaped profile 48 at the edge of the veneer panel.

In addition, it can be seen in Fig. 2 and an edge strip 50 of the veneer board, which was indeed separated at the location of the grinding tool 30 with the help of the circular saw blade 32 of the 15 veneer panel, but, if it is not broken, still hangs on the veneer board.

In Fig. 3, the trimming device 28 can be seen with the circular saw blade 32.

In Fig. 4, an edge zone of the veneer board 14 in the state after the shank is shown.

One recognizes the wedge-shaped Schäftung 48, which, however, does not leak to the free end absolutely acute, but forms a blunt abutment edge 52 of very low height. The height of this abutting edge 52 can be controlled by adjusting the height of the grinding tool 30 relative to the backing 22.

OK

Dashed lines in Fig. 4, the original state of the edge 26 of the veneer board is shown. It is assumed here that the veneer sheet 14 has already undergone a pre-stenching prior to reaching the shaving apparatus 10 described herein, for example, a wet shearing prior to drying the veneers. The edge 26 has des- half even in the state in which it reaches the shifter 10, a wedge-shaped figure, however, is disturbed by numerous cracks and outbreaks 54. By performing with the shank device 10 Schäftung these cracks and breakouts are removed, so that you get a clean business edge.

Fig. 5 shows schematically a side view of a strand 56 of glued veneer sheets 14 and 58, which are superimposed in several layers. The strand 56 is transported on the laying line not shown in detail from left to right in Fig. 5 to a press, not shown. The upper and lower topsheets of the strand 56 are formed by veneer sheets 14 which have been post-processed in the shaving apparatus 10 according to the method described above. On the other hand, the inner layers are formed by veneer sheets 58, which have been subjected only to wet-shearing. It can be seen that wet shearing was performed both on the veneer sheets 58 of the inner layers and on the veneer sheets 14 of the outer layers on both edges running transversely to the strand direction, so that the sheets can overlap each other with their shanks and thus with a veneer layer form substantially constant thickness.

It should be noted that the shanks are formed on both edges of each veneer panel on the same side of the panel, in the example shown at the bottom. However, the stringer zones later covered by the shear zone of the subsequent panel (at the left-hand end of each panel in Figure 5) bend downwardly (at the latest during the subsequent extrusion of the string) due to the weight of the panels above in Fig. 5, it looks as if the panels were left at the top at the top.

In Fig. 5, only three inner layers of the veneer sheets 58 are shown. In practice, however, the number of inner layers is usually much greater. Also the thickness , C) _

the individual veneer sheets 14 and 58 is exaggerated in Fig. 5 in relation to the length.

The (Nach-) Schäftung with the shifter 10 is made in the example shown only on one edge of the veneer panel 14, in the upper cover layer in each case at the right in Fig. 5 end. In this way, on the upper side of the upper cover layer of the strand 56, the straight and clean abutting edges 52 are obtained which ensure a clean appearance of the veneer plywood body formed after pressing. At the opposite edges of the veneer panels 14 (on the left in FIG. 5), it is not necessary to add any additional parts, since these edges are in any case covered by the overlying hinge zone of the respectively following veneer panel.

However, when laying the lower cover sheet, the veneer sheets 14 are applied in opposite orientation so that the clean abutting edges 52 are each at the left end of each veneer sheet and thus also at the end visible from the outside.

In the state in which the veneer sheets 14 and 58 leave the drying station, all veneer sheets have substantially the same rectangular plan. However, the corrugated boards for the cover layers are slightly shortened by the shanks in the shank device 10, so that they no longer fit exactly in the grid of the veneer sheets 58 of the inner layers.

When laying the veneer sheets, which ultimately form the strand 56, one proceeds as follows: First, the veneer sheets 14 of the lower cover layer are laid. Meanwhile, the veneer sheets 58 of the inner plies are put into "books" each consisting of staggered sheets, in the example shown each of three sheets, in the general case of N sheets, if N is the number of veneer sheets of the inner plies of the billet , The individual books are then placed one after the other on the lower cover layer and placed together so that they placed lower cover layer and thereby placed together so that they together form the core of the strand 56. Subsequently, the veneer panels 14 of the upper cover layer are placed. In Fig. 5, Sl designates the position of the front edge of a lower veneer board 58 of a book. S2 indicates the position of the front edge of the middle veneer board 58 of the same book, and accordingly S3 indicates the position of the front edge of the topmost veneer board 58 of this book. It can be seen that the distance Di between the positions S 1 and S2 is the same as the distance between the positions S2 and S3. That is, the offset of the veneer sheets from layer to layer corresponds to a uniform grid for all inner layers.

With S4, the position of the front edge of the veneer board 14 is referred to, which rests on the ending at S3 book. The distance D34 between these positions is significantly different from Di. S5 denotes the position of the leading edge of the uppermost veneer sheet 58 of the succeeding book, and S6 denotes the position of the leading edge of the associated veneer sheet 14 in the upper cover sheet. The distance D56 between these positions is different not only from Di, but also from the distance D34 between the preceding pair of veneer sheets in the same layers. The veneer sheets 14 of the topsheets are thus laid in their own rhythm, which depends on the length of these veneer sheets and is different from the rhythm of the successive books in the inner layers.

However, if the veneer sheets 14 in the shaving apparatus 10 are all brought to the same length, the laying of the lower and upper cover sheets may be done with a fixed tact which is different only from the timing when laying the books for the inner sheets. However, it is also possible to control the shed device 10 and the belt conveyor 12 so that the lengths of the post-veneer boards 14 vary. For example, the camera 24 may also be used to detect and electronically evaluate the cracks and breakouts 54 in the male edge 26. The projection of the edge 26 on the pad 22 and thus the width of the edge strip 50 which is separated with the circular saw blade can therefore be made dependent on the size of the outbreaks. In that case, it is also convenient to electronically detect the leading and trailing edges of the veneer sheets even when laying the veneer sheets 14, and to control the laying process so that the veneer sheets are abutted with the correct overlapping of the stitching zones.

Optionally, it is even possible in this variant of the method to remove any imperfections from the interior of the veneer panel 14. For example, if an intolerable defect is near the leading edge 26, the belt conveyor 12 may be controlled to bring that defect to a position beyond the base 22 so as to sever the defective portion of the veneer board with the trimming device 28 becomes. In this case, since the cut with the circular saw blade will generally be made at a position where the veneer board has its full thickness, more material has to be removed with the grinding tool 30. If necessary, the speed at which the carriage 18 is moved across the width of the veneer panel can be adjusted.

Claims

A method of shanking veneers (14), characterized in that an edge (26) of the veneer (14) is pressed against a base (22) with a pressure shoe (44) extending along this edge in such a way that the edge overlies the edge Protects pad, and that a trimming device (28) and a grinding tool (30) having an obliquely inclined to the plane of the veneer grinding surface, along the edge (26) of the veneer, so that with the Besäumvorrichtung (28) an edge strip (50 ) of the veneer is cut and the veneer is dealt with the grinding head (30).

2. The method of claim 1, wherein the trimming device (28) and the grinding tool (30) are moved together along the edge (26) of the veneer along.

3. The method of claim 1 or 2, wherein the Besäumvorrichtung (28) in the movement along the edge (26) of the veneer ahead of the grinding tool (30).

A method according to any preceding claim, wherein the veneer (14) is fed to the base (22) on a conveyor (12), the edge (26) of the veneer is electronically captured during transport on the conveyor (12), and the projection of the edge (26) on the pad (22) by controlling the conveyor (12) is controlled.

5. The method of claim 4, wherein the edge (26) of the veneer with a measuring system (24) is detected, the state of the edge (26) evaluated by evaluating the measurement data, and the projection of the edge (26) over the pad (22) is controlled based on the detected state of the edge.

6. Apparatus for carrying out the method according to one of claims 1 to 5, characterized by a frame (16) which forms a base (22) for a veneer panel (14), an adjustable pressure shoe (44) for pressing the veneer panel against the substrate (22), and a trolley (18) movable on the frame (16) along an edge (26) of the veneer tray (14), on which a trimming device (28) for separating an edge strip (50) from the edge (26 ) of the veneer panel and a grinding tool (30) for shearing the edge are arranged.

7. Device according to claim 6, comprising a conveyor (12) for feeding the veneer sheet (14) to the base (22), and a measuring system (24) arranged above the conveyor (12) for detecting the edge (26) of the veneer sheet (12). 14) during transport on the conveyor.

8. Apparatus according to claim 7, wherein the measuring system is a camera (24), a light curtain or a scanner.

9. A method for producing laminated veneer lumber, in which a strand (56) of several layers of glued and busy veneer sheets (14, 58) is laid, characterized in that at least the veneer sheets (14) forming a cover layer of the strand (56) , be operated by the method according to one of claims 1 to 5.

10. The method of claim 9, wherein all the veneer sheets (14, 58) are pre-studded at both transversely to the direction of the strand (56) extending edges, before the veneer sheets (14) for the cover layer with the method according to one of claims 1 to 5 to be rebuilt.

A method according to claim 9 or 10, wherein the veneer sheets (14) for the top layer are laid asynchronously with respect to the veneer sheets (58) of the inner layers.