JPH0250841B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a veneer veneer (hereinafter referred to as a veneer).
This invention relates to a method for processing log ends used for cutting.

Conventionally, when cutting a veneer from a log having cracks at the end of the wood due to dry cracks, water cracks, etc., cracks corresponding to the cracks were inevitably formed in the veneer.

When plywood is manufactured using a veneer with cracks, the quality of the plywood inevitably deteriorates due to the cracks appearing on the end faces of the plywood. This means that the wider the crack, the lower the quality. Although this drawback can be avoided by cutting out the portion containing cracks from the raw wood or veneer, the veneer yield inevitably decreases.

On the other hand, when manufacturing plywood, a number of loads are applied to the veneer. When cracks exist in the veneer, various loads act intensively on the cracks in the veneer, making it easy for the veneer to tear using the cracks as starting points. As a result, this has become a factor that causes various problems such as hindering the rationalization and labor saving of the manufacturing process, and lowering the veneer yield due to cutting out the torn portion.

Therefore, for example, as disclosed in ``Method for preventing cracks in veneers or veneers, etc.'' (Japanese Patent Publication No. 15893/1983), adhesives or thin plates or
Attempts have been made to solve the various disadvantages described above by press-fitting a filler mixed with wood flour or the like and bonding or filling the cracks.

However, in the conventional method described above, when press-fitting adhesive etc. into a crack, it is difficult to press-fit the adhesive etc. to the crack surface with almost uniform pressure, and it is difficult to obtain the required adhesive action. This was actually difficult. Furthermore, it is difficult to avoid deterioration in the quality of the plywood due to the wide filling of different parts, and the cracks themselves still stand out from other parts.
The reality is that there is almost no preventive effect on veneer tearing due to load concentration, and sufficient results have not necessarily been achieved.

The present invention was invented in order to solve the above-mentioned conventional drawbacks, and its purpose is to rationally solve various problems that occur in veneers due to cracks in raw wood, with a simple configuration. It is an object of the present invention to provide a method for processing log ends, which can solve the above problems, improve plywood quality and veneer yield, and promote rationalization and labor saving in the plywood manufacturing process.

For this reason, the present invention makes the cracks in the veneer less noticeable and reduces the load on the cracked parts by forming an appropriate number of new cracks along the cracks near the end of the log. It is possible to suppress tearing of the veneer due to concentration.

Hereinafter, the present invention will be described in detail according to embodiments shown in the drawings.

As shown in FIG. 1, the wood end treatment method according to the present invention is intended for raw wood 1 in which cracks 3 due to dry cracks, water cracks, etc. exist in the wood end 2. As shown in FIG. 2A, the end 2 of the log 1 is
By driving a crack forming tool 4 of an appropriate shape such as a wedge shape into the vicinity of the crack 3, an appropriate number of new cracks 5 are created.
is formed along the crack 3. At this time, as the crack 5 is formed, numerous fluffs of wood fibers are generated on the inner surface of the crack 5, so even after the crack forming tool 4 and the like are removed, the crack 5 never closes as before.

As shown in FIG. 2B, regarding the veneer S cut from the raw wood 1 in which the crack 5 is formed near the crack 3 as described above, the crack 5 has an appropriate width in the veneer S. It remains with l1 maintained.
As a result, the width l2 of the crack 3 in the veneer S corresponding to the crack 3 in the raw wood 1 becomes narrower than the original (initial) width, and the load during plywood manufacturing is distributed to the crack 5, which causes the crack to crack. This avoids the concentration effect on 3. As a result, the risk of the veneer itself being torn under load is reduced compared to the case where the veneer itself has only the cracks 3.

For example, by changing the sharpness of the crack forming tool 4,
By changing the degree of fluff, etc.
It is possible to arbitrarily set the width of the crack 5.
In this case, in order to effectively prevent the deterioration of plywood quality, it is preferable to restrict the width of both the crack 5 and the crack 3 to 1 mm or less, and the width of the crack 3 is equal to the width of the crack 5 and the number thereof. Since the cracks 5 are narrowed by the corresponding width, it is preferable that the number of cracks 5 is set according to the original width of the crack 3 and the width of the crack 5, and that the cracks 5 are formed in a distributed manner on both sides of the crack 3. Further, the depth of the crack 3 (width with respect to the core direction of the raw wood 1) needs to be deep enough to reliably reach the position remaining in the veneer S when forming the plywood.

In addition, as an effective modification example of the present invention, as shown in FIGS. 3A and 3B, an appropriate number of new cracks are created in the vicinity of the cracks 3 of the end 2 of the log 1 by the same means as in the above embodiment. 5 is formed along the crack 3, the crack 5 is formed by applying a thermosetting adhesive, for example, to at least one of the cracks 3 (both in the example).
Filled with various adhesives 6 such as thermoplastic adhesives or wet curing adhesives. Compared to the conventional processing method described above, this processing method makes it easier to pressurize and distribute the adhesive 6 almost uniformly by elastically deforming at least one side of the crack 3 and crack 5. , it is possible to maintain the crack 3 and/or crack 5 at a desired width due to the high adhesive strength.

In addition, in the modified embodiment described above, the crack 3 and/or the crack 5 is filled with the adhesive 6 entirely, but for example, the crack 3 and/or the crack 5 is filled with the adhesive 6 locally. It may also be in the form of filling. In other words, the point is that cracks 3 and/or
Alternatively, any form may be used as long as the width of the crack 5 can be maintained as desired. Therefore, the cracks 3 and 5 can be filled with a filler made by mixing various types of adhesives 6 with a reinforcing agent such as wood flour, or with reinforcements such as pieces of wood formed into a shape corresponding to the cracks 5. It is also possible to use a filler made of wood coated with various adhesives.

Further, as an application example of the present invention, as shown in FIG. "Itoiri Knives" related to
A cut smaller than the thickness of the veneer S is formed on the outer circumference of the log 1 along the butt end 2 using a thread inserting knife 8 whose blade is provided with a thread guide blade as disclosed in Japanese Patent Publication No. 63202) etc. In addition, there is an application example in which a reinforcing thread 7 coated with various adhesives 6 is buried in the cut as necessary. In this case, since the cuts are formed in the raw wood state, the deviation of the wood fibers due to cutting resistance can be reduced compared to the case where the cuts are formed in the wood veneer state, and the reinforcing and adhesive effects of the reinforcing threads 7 can be reduced. The veneer S is cut using the cutting blade 9.
The width of the cracks 3 and 5 can be maintained approximately as desired.

In addition, in each of the above embodiments, the crack 3 in the direction orthogonal to the axis of the log 1 was explained.
The wood end treatment method according to the present invention can also target arc-shaped cracks that occur along the growth rings, so-called eye-shaped cracks.

As clarified above, according to the wood end treatment method of the present invention, new cracks are formed in the vicinity of existing cracks in raw wood, and the width of the cracks becomes narrower, so that the plywood quality due to the presence of cracks is reduced. Since the deterioration of the veneer is significantly improved compared to the conventional method, and there is no need to cut out the portions containing cracks, the veneer yield can also be significantly improved compared to the conventional method.

In addition, by forming new cracks in the vicinity of cracks, the load that acts on the veneer during plywood manufacturing is dispersed to new cracks other than cracks.
It is possible to avoid the concentrated effects of loads on the cracks and to reduce the possibility of veneer tearing. As a result, it is possible to promote rationalization and labor-saving of the veneer processing during plywood production, and it is also possible to avoid a decrease in the veneer yield due to the cutting process of the torn portion, which is extremely effective.

[Brief explanation of drawings]

Figure 1 is a perspective illustration of raw wood with cracks, Figure 2
Figure A is a perspective explanatory view showing how cracks are formed in raw wood, Figure 2 B is an enlarged explanatory diagram of a veneer cut from the raw wood illustrated in Figure 2 A, and Figure 3 A is an adhesive applied to the cracks. FIG. 3B is a perspective explanatory view showing the filling state of the third
FIG. 4 is an enlarged view of the arrowed portion in FIG. In the diagram, 1 is the log, 2 is the end of the log, 3 is the crack, and 4
5 is the crack forming tool, 5 is the crack, 6 is the adhesive, 7 is the reinforcing thread, l1 is the width of the crack, and l2 is the width of the crack.

Claims (1)

[Claims] 1. A method for treating the end of a log, which comprises forming an appropriate number of new cracks along the crack in the vicinity of the crack existing at the end of the log.