JPS6155841B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vertical splicing method for joining the ends of two veneers in the direction of their fibers.

Conventional vertical splicing of veneers is a so-called plain scarf joint, in which the end of the veneer is simply scuffed in one plane, so in the gluing process,
Overlapping or misalignment can occur in the adhesive layer, resulting in poor adhesion, or the bonding strength is weak.In addition, in order to achieve a bond without overlapping or misalignment, it is necessary to stand still until the adhesive is completely fixed. However, it had the drawback of extremely poor efficiency.

This invention was developed with the aim of solving these shortcomings of the conventional method, and it divides the end portion of two veneers to be vertically separated into a plurality of end portions in the width direction, and The parts are scarfed with a predetermined scarf ratio so that the widths are equal and the slopes are normal, and the adjacent butt ends are sloped in the opposite direction, and each scarf surface is interposed with adhesive to form both veneers. This is to perform vertical stripping.

The present invention will be explained below with reference to embodiments shown in the drawings. The two veneers 1 and 2 have approximately the same thickness T and width W, and the end portion 3 of the veneer 1 and the veneer 2
The butt ends 4 indicate the ends in the direction of the fiber direction F, respectively. The end portions 3 and 4 of each veneer 1 and 2 are divided into a plurality of end portions 3a, 3b, 3c, . . . and end portions 4a, 4b, 4c, . . . in the width direction, respectively. Separate. In this case, the butt ends 3 and 4 that face each other, for example, the butt ends 3a of the butt ends 3 and the butt ends 4a of the butt ends 4, the butt ends 3b and the butt ends 4b,
Divide opposing butt ends so that their widths are equal. Note that the divisions in the width direction of the butt end portion may be of the same width or different widths, and the number of divisions of the butt end portion may be an appropriate number of 2 or more depending on the thickness, width, etc. of the veneer (in the example, the number of divisions is 5). ).

Then, a scarf is applied to each of these divided butt ends. In this case, the scarf ratio, that is, the ratio of the joint length L of the scarf surface 5 to the thickness T of each veneer 1 and 2, is approximately 1:3 to 1:3 depending on the thickness, width, material, etc. of the veneers. The scarf is processed so that it has a predetermined equal value of 1:10. In addition, the scarf surfaces 5 of the opposing butt ends are normally inclined, that is, when the butt ends of each other are brought into contact with each other, the scarf surfaces 5 are inclined in the same direction, as shown in the scarf surfaces 5 of the butt ends 3b and 4b shown in FIG. Scarf processing is applied, and in addition, the scarf surfaces 5 of the adjacent butt ends are reversely sloped,
That is, if one of the butt ends is inclined from the butt surface of the back side of the veneer toward the surface, as in the butt ends 3b shown in FIG. 4 and the butt ends 3c shown in FIG. Each scarf surface 5 is scarfed so that it slopes from the end surface of the front surface of the board toward the back surface. In addition, as a means for performing scarf processing, for example, a plurality of blades whose width matches the width of the divided butt end portions is used.

Scarf surface 5 with scarf processing like this
Using adhesive G, as shown in FIG.
Vertical strip joints are performed. When the veneers 1 and 2 are green veneers containing a large amount of moisture, the adhesive G interposed on the scarf surface 5 may be a urethane resin adhesive or a modified polyamide hot veneer that can bond green veneers. Use a wet wood adhesive such as melt glue, or in the case of dry veneer, use a thermosetting adhesive such as urea resin adhesive, a room temperature curing adhesive such as vinyl acetate, or a dry adhesive such as hot melt glue. Use an appropriate adhesive that can join the plates.

As described above, this invention divides both end portions of two veneers into a plurality of end portions of the same number in the width direction,
Scarf processing is performed with a predetermined scarf ratio so that the divided opposing butt ends have equal widths and are sloped in the same direction, and adjacent butt ends have opposite slopes, and an adhesive is applied to the scarf surface. Since the structure is such that the scarf surfaces are butted against each other and the vertical strip joint is performed, separation is prevented by the oppositely sloped scarf surfaces in the direction perpendicular to the veneer surface, and each end part is prevented from separating in the width direction. The sides of the scarf prevent lateral displacement, making it possible to perform good joining without overlapping or displacement.Also, by making the widths of the opposing ends equal, the entire scarf surface can be joined and the aforementioned displacement can be prevented. This makes it possible to make a strong bond, set the scarf ratio as low as possible, and perform vertical stripping with a good yield.Furthermore, even if the adhesive interposed on the scarf surface is uncured, the bond can be easily bonded. It has the advantage of being able to move the board and perform highly efficient vertical splicing, and by enabling highly efficient, strong and good vertical splicing of veneer,
This makes it possible to effectively utilize veneers with insufficient dimensions in the fiber direction, which could not previously be used for plywood, and contributes to a significant improvement in the yield of plywood production.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a plan view showing the end portions of two scarfed veneers, FIG. 2 is a side view of FIG. 1, and FIG. Side view showing the state in which the wood end of the board is vertically ripped off, No. 4
The figure shows a sectional view taken along the line E--I in FIG. 1, and FIG. 5 shows a sectional view taken along the Ro-Ro line in FIG. 1, 2...Single board, 3, 4...Kibute, 3a, 3
b, 3c, 3d, 3e, 4a, 4b, 4c, 4
d, 4e...End part, 5...Scarf side, T...
... Thickness of the veneer, W... Width of the veneer, F... Fiber direction, L... Joint length, G... Adhesive.

Claims (1)

[Claims] 1 The butt ends of two veneers having approximately the same thickness and width are each divided in the width direction into a plurality of butt ends with the same width or different widths, and the opposing butt ends of the divided butt ends are Scarfing is performed with a predetermined scarf ratio so that the scarfs are equally and forwardly sloped, and each adjacent butt end has a reverse slope, and an adhesive is interposed on each scarfed surface. A veneer vertical stripping method characterized by joining both veneers.