JPH044B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention deals with a large number of pieces of wood (hereinafter referred to as small-diameter wood) that can form voids when bundled with the same fiber direction.
This invention relates to an adhesive molding method.

Conventionally, in order to make effective use of small-diameter wood, a technique for increasing the diameter of a large number of small-diameter trees by making the fiber direction the same is disclosed in Japanese Patent Application Laid-open No. 56-70902 (title of invention: veneer for plywood) by the applicant of the present application. (manufacturing method).

However, the above technology has the following drawbacks. In other words, when filling and gluing a filler into a space between bundled small-diameter trees, it is practically difficult to match the shape of the filler to the space, and as a result, the shape of the filler and the small-diameter The strength of the bond with the tree and the strength of the large-diameter log itself after bonding become unstable.

The present invention fundamentally solves these difficulties and provides a technique for increasing the diameter of small-diameter trees, which can ensure more stable adhesive strength.The details thereof are as follows.

What is shown in FIGS. 1 and 2 is an example of a method for increasing the diameter of a small-diameter tree 1 into a cylindrical shape. , a large number of small trees 1 are placed in a formwork consisting of an upper formwork 3, with adhesive applied to their outer peripheral surfaces,
Moreover, the fibers are bundled with the fiber direction generally the same (first
state). Next, the internal volume of the mold is reduced using a hydraulic press 4 to cause deformation of each small-diameter wood 1, and the spaces between the small-diameter wood are filled, and this state is maintained at least with a stopper until the adhesive is completely cured. 5 (state shown in Figure 2) and adhesively molded.

In this example, we used peeled core of larch generated from veneer lace as the small diameter tree, so the cross section is shown as an equal circle in Figure 1, but if thinned wood is used, an irregular circular cross section will be used. becomes. After the compression process, as shown in FIG. 2, the cross-sectional shape of each piece changes considerably, taking on a hexagonal shape, and the bonding area between the small-diameter pieces of wood increases. Incidentally, in the case of this example, focusing on the cross-sectional area, the initial formwork internal volume was set to 100
In this case, the cores with a volume of 75 were bundled together in the mold, and then the volume inside the mold was reduced to 60 and adhesive molded, so the core itself was essentially
Its volume has been reduced by 20% due to compression, giving it a tortoise shell shape. Of course, since it is wood, it is 50%
Although it is possible to reduce the volume to a certain degree, pointless and excessive compression will result in a large loss, so in this example, the deformation is carried out to the extent that the voids between the cores are almost eliminated. It was carried out as a guideline.

In order to maximize the bonding area between the small-diameter trees as described above, when carrying out the present invention as an adhesive molding with almost no space between the small-diameter trees,
Although it depends to some extent on the species of small-diameter trees, assuming that the filling rate of small-diameter trees bundled in the formwork initially is A (75% in the case of the above example), the internal volume of the formwork is approximately the square of A. (approximately 56% in the case of the above example) or less (approximately 56% or less in the case of the example above), causing deformation of the small diameter wood in the formwork. It is a good idea to use this as a guide. In addition, when adhesive molding is performed to such an extent that some voids 11 remain between the small-diameter trees 1 as shown in FIG. It is desirable to reduce the internal volume of the frame as a guideline, and by doing so, a sufficient bonding area between the small-diameter trees can be ensured for practical purposes. Note that the above guideline is for the case where a large number of small-diameter trees are enlarged to a simple shape such as a cylinder or a prism. In any case, as indicated by 8 in Fig. 1, in the space between each small-diameter tree, place a supplementary material of an appropriate shape with a triangular, square, or circular cross section, such as a tree branch or sawn lumber. , replenishing lumber scraps, veneer boards, veneer scraps, etc., or appropriately distributing and bundling small-diameter wood of various sizes and shapes, or pre-processing small-diameter wood into an appropriate shape. By increasing the filling rate A by, for example, achieving thorough bundling, it is possible to further reduce the extent to which the internal volume of the mold is reduced, and it is also possible to reduce substantial loss due to compression.

In addition, in carrying out the present invention, it is important to cause some deformation to the small-diameter wood to expand the adhesive area, so it is effective to soften the small-diameter wood in advance, and if necessary. Depending on the situation, preliminary treatments such as boiling, steaming, or microwave heating are carried out. Such small-diameter wood is considerably easier to compress and deform. Furthermore, after bundling the small-diameter wood in the formwork and compressing it, an overcompression step is involved in which the internal volume of the formwork is temporarily reduced excessively, and then restored and maintained in a predetermined compressed state. is also effective. For example, in the embodiment described above, during the transition from FIG. 1 to FIG.
This method returns the wood to the state shown in Figure 2, and if this operation is performed once or a suitable number of times, the deformation of the small diameter wood changes from an elastic state to a considerable plasticity, and it maintains a stable shape even after adhesive forming. It also stabilizes the bond between small-diameter trees.

Therefore, the large-diameter glue-formed logs obtained by the present invention will maintain a predetermined state due to the strength of the adhesive after being removed from the formwork, but each small-diameter log will remain in a predetermined state due to the strength of the adhesive. Because it involves deformation,
Those made from relatively hard wood species have a tendency to decompose due to elastic recovery. However, since the elastic recovery of wood occurs quite slowly, there will be no particular problem if the desired processing is carried out using a veneer lace, slicer, saw, etc. immediately after the adhesive has sufficiently hardened. There are many. In addition, if there is a problem, either maintain the compressed state for the necessary curing time in the formwork to plasticize the wood, or boil or steam the wood while keeping it compressed in the formwork or other holding member. Wood softening treatment such as boiling or microwave heating may be applied. Long-term shape stabilization can be achieved.

On the other hand, regarding the adhesive used in the present invention, it is common practice to select the adhesive and determine the bonding conditions depending on the moisture content of the small-diameter wood to be used. In some cases, wet curing adhesives with high heat resistance are suitable. Furthermore, regarding the application of the adhesive, it is not necessarily necessary to apply it to all of the small-diameter trees to be used, and it may be applied to only one of the adjacent small-diameter trees. If it is not necessary to coat the entire outer circumferential surface of a small-diameter tree, apply it partially. Of course, the same applies to the refill material.

Further, the design of the mold can be changed as desired, and in addition to the batch type mold as in the above embodiment, a mold for continuous molding can also be used. For example, there is a method in which a large number of pairs of rolls are arranged in a row, and small-diameter wood is compressed gradually from the top to the bottom.
The desired shape is finished using the peripheral surfaces of each pair of rolls.

The large-diameter logs 9 created as described above are formed into approximately a predetermined shape as shown in FIG. 3, but the small-diameter logs 1 may be used by butting short pieces together as necessary. can. In such a case, there are cases where adhesive is applied to the butt points 10 to bond them, and cases where the butts are simply butted together, but in both cases, it is better to shift the butt points 10 sequentially as shown in Figure 3. . In addition, Fig. 2 and Fig. 4
The tortoiseshell-shaped wood end pattern shown in the figure has high commercial value, and in order to take advantage of this pattern, the wood end can be sequentially sliced thinly to make decorative veneer or decorative board. Diameter technology also creates new value.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 illustrate an embodiment of the method of the present invention, and Fig. 1 and Fig. 2 are both cross-sectional views showing small-diameter wood in the formwork in cross-section, and Fig. 3 4 is a perspective view of the log with a larger diameter, and FIG. 4 is a cross-sectional view. In the figure, 1 is small diameter wood, 2 is the lower formwork, 3 is the upper formwork, 5 is the stopper, 9 is the large diameter log, 10
is the matching point, and 11 is empty.

Claims (1)

[Claims] 1. A large number of small-diameter pieces of wood, which would have gaps if they were bundled with the fibers in the same direction, are bundled in the same direction in a predetermined formwork with adhesive applied to their outer peripheral surfaces, The internal volume of the mold is reduced to cause deformation in each small-diameter wood, and the adhesive area between the small-diameter wood is expanded, and this state is maintained at least until the curing of the adhesive is completed to adhesively mold the small-diameter wood. A method for bonding and forming small-diameter wood.