JPH03193401A - Longitudinally joining method for veneer - Google Patents

Abstract

PURPOSE:To accurately join the oblique faces and also to enable joining while carrying a veneer by forming the joining face of a woodworking part into a stepwise shape wherein the oblique face, a vertical face in the central vicinity thereof or a reverse oblique face are provided. CONSTITUTION:The woodworking part 2 of one side of veneer 1 to be vertically joined is cut and formed into a joining face 10 which is constituted of a stepwise first oblique face 7 described hereunder, a vertical face 8 and a second oblique face 9. The first oblique face 7 is provided in a range of the prescribed distance toward the surface 6 from a woodworking end edge 5 wherein the rear 4 crosses the woodworking face 2. Further the woodworking part 2 - 1 of the other veneer 1 - 1 is cut and formed into a joining face which is constituted of a stepwise second oblique face 9 - 1 described hereunder, a vertical face 8 - 1 and a first oblique face 7 - 1. The stepwise second oblique face 9 - 1 can be closely mated with a joining face 10 - 1 provided in a range of the prescribed distance toward the rear 4 - 1 from a woodworking end edge 5 - 1 wherein the surface 6 - 1 crosses a woodworking face 3 - 1. Both joining faces are allowed to butt by interposing a thermosetting type adhesive or a thermoplastic type adhesive between both joining faces. When the adhesive is cured while exerting pressure to the direction of fiber, longitudinal joining of veneer is obtained which is strongly joined in the joining faces.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for vertically splicing veneers to join them in the fiber direction in a plywood manufacturing process.

(Prior Art) As a conventional method for vertically splitting veneers, the plain scarf joint method, which allows easy processing of the joint surface, has been mainly used.

(Problems to be Solved by the Invention) The plain scarf joint method has the advantage of being easy to process since it only forms an inclined surface at the end of the veneer, but it is difficult to precisely match the inclined surfaces. This method is difficult and often results in defective joints with different levels, and since it is not possible to join the veneers while transporting them, there are problems such as poor efficiency.

(Means for Solving the Problem) The joint surface of the butt end is formed into a stepped shape with an inclined surface and a vertical or reversely inclined surface near the center thereof.

(Function) The vertical surface or reversely inclined surface provided near the center of the inclined surface increases the joining area and provides a locking action during transport welding.

(Example) When longitudinally stripping the end portion 2 of one veneer 1 in the fiber direction and the end portion 2-1 of the other veneer 1-1 in the fiber direction shown in FIG. The wood end part 2 has a wood end surface 3 and a back surface 4.
A first inclined surface 7 that is inclined at an inclination angle θ with respect to the back surface 4 from the linear wood end edge 5 where these intersect, and a vertical surface 8 that is perpendicular to the back surface 4 or the front surface 6 and an inclination angle θ1 with respect to the front surface 6. A step-like joint surface 10 consisting of an inclined second inclined surface 9 is moved at a predetermined distance L from the butt end edge 5 to the intersection line of the second inclined surface 9 and the surface 6.
(This predetermined distance is usually set to 3 to 6 times the veneer thickness T.) The veneer is formed by cutting with a cutting machine such as a circular saw. In addition, in the end portion 2-1 of the other veneer 1-1, there is a surface 6- 1 and a second inclined surface 9 having the same length as the second inclined surface 9 inclined by an inclination angle θ1.
-1 and a vertical surface 8-1 of the same length as the vertical surface 8 perpendicular to the front surface 6-1 or the back surface 4-1, and a vertical surface 8-1 of the same length as the first inclined surface 7 inclined by the inclination angle θ with respect to the back surface 4-1. The step-like joint surface 10-1 consisting of the first inclined surface 7-1 is spread over a predetermined distance from the butt end edge 5-1 to the intersection line of the first inclined surface 7-1 and the back surface 4-1. It is formed by cutting with a cutting machine such as a circular saw. In this case, the first inclined surface 7 and the first inclined surface 7-
1. The second slope 9 and the second slope 9-1 are both set to have the same slope angle, but the slope angle θ of the first slope 7 and the slope angle θ1 of the second slope 9 are the same as those of the veneer. It can be changed somewhat in consideration of back cracks, etc., and the first slope 7 and the second slope
Even if there is a slight difference in the length of the inclined surface 9, it can be carried out in the same way, and furthermore, the length of the vertical surface 8.8-1 is the same as that of the joint surface 1.
Since it forms a locking part when joining 0.10-1, the longer it is, the more effective it is, but if it is too long, the inclination angle θ or θ1 may become small and the strength may decrease. , usually a few minutes of the veneer thickness T - i.e. 3 to 4 mm
In the case of a thick veneer, it is desirable to set the thickness to 1 mm or less.

In this way, the joint surface 10 cut and formed on the butt end 2 of one veneer 1 and the joint surface 10-1 cut and formed on the butt end 2-1 of the other veneer 1-1 are connected to the inclination angle of the slope. Since the lengths and the lengths of the vertical planes are set equal, when the joint surfaces 10 and 10-1 are butted against each other, they are in close contact as shown in FIG. A thermosetting adhesive such as urea resin, melamine resin, or phenol resin or a thermoplastic adhesive such as a hot melt resin adhesive is interposed between the two joint surfaces, and while applying pressure in the direction of the fibers, thermosetting is performed. In the case of mold adhesives, the adhesive is cured by heat pressing from the front and back sides with a hot plate or by roller pressure and high frequency heating, and in the case of thermoplastic adhesives, roller pressure and cold air are applied as necessary. This allows the adhesive to harden and the veneer to be firmly joined at the joint surface to be vertically spliced.

In addition, since the vertical plane forms a locking part, the rear veneer is conveyed in the direction of the fibers and is stopped at the joint surface of the front veneer, as in the case of cross-splitting of veneers using the push-feed method. It is possible to join the joint surfaces of the veneers by colliding them with each other and pushing them forward.In this case, if a hot melt type adhesive is used as the adhesive, the adhesive will harden quickly and will be highly effective. Able to perform efficient vertical stripping. Furthermore, when a vertical surface is formed on the joint surface, this vertical surface becomes a butt joint, but it has been experimentally found that the area near the center of the joint surface has almost no effect on the bending strength. There is.

The embodiment shown in FIG.
a, 8a-1 is formed by cutting, and the veneer 1 has a reverse slope 8a (the slope opposite to the first slope 7 and the second slope 9).
The veneer 1-1 has a reverse slope 8a-1 (first slope 7-1).
1 and 2 (slanted surfaces opposite to the second inclined surfaces 9-1) are cut and formed, and a wedge is formed by the protrusion P formed on the veneer 1 and the protrusion P-1 formed on the veneer 1-1. This allows for similar engagement. Also in this case, the first inclined surface 7 and the first inclined surface 7-1 and the second inclined surface 9 and the second inclined surface 9
-1 have the same length and the same angle of inclination, and the reversely inclined surface 8
A and the reverse slope surface 8a-1 also have the same length and slope angle θa.

As θ1a, the joint surface lOa of the veneer 1 formed by the first slope 7, the reverse slope 8a and the second slope 9, the second slope 9-1, the reverse slope 8a-1 and the first slope When the bonding surfaces 10a-1 of the veneers 1-1 formed by the surfaces 7-1 are brought into contact with each other, they are brought into close contact.

(Effect of the invention) In FIG. 2, the slope Q indicated by the dashed line is formed by the brace calf joint method at a predetermined distance, and the slope Q has a tJ1 slope as is clear from the figure. Corresponds to one side of each triangle formed by the surface 7 and a part of the vertical surface 8 and the second inclined surface 9 and a part of the vertical surface 8,
The length of the slope Q is shorter than the joint surface formed by the first slope 7, the vertical surface 8, and the second slope 9, and the joint area of the present invention is larger, and when set at the same predetermined distance. Therefore, by forming a vertical surface on the joint surface, the predetermined distance can be set shorter than that of a brace joint, which improves the yield with almost no effect on bending strength. It can be peeled off, and the vertical or reversely sloped surface formed on the joint surface serves as a locking part when the joint surfaces are butted, but it is possible to achieve a good vertical seam with accurate butt and no unevenness. In addition, it is possible to join the veneers while transporting them in the direction of the fibers, making it possible to perform highly efficient vertical splicing of the veneers.Furthermore, the joining surface can be processed using a circular saw, etc., as in the case of Brainscarf. Similarly, it has various effects such as being easily performed.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view showing a joint surface formed by cutting the end portions of both veneers to be vertically separated, and FIG.
The figure is a side view showing a state in which the joint surfaces cut and formed on both veneers are butted together, and FIG. 3 is a side view showing another embodiment of the joint surfaces cut and formed on the butt ends of both veneers. 1.1-1... Single board, 2.2-1... Wood end, 3.
3-1...Kibutsu side, 4.4-1...Back side, 5.5-
1... End edge, 6.6-1... Surface, 7.7-1
...First inclined surface, 8.8-1... Vertical surface, 8a, 8
a-1... Reverse inclined surface, 9.9-1... Second inclined surface, 10, 10-1, 10 a, 10 a
-1-joint surface, D...fiber direction, L...predetermined distance,
T...Single plate thickness, P, P-1...Convex part, Q...
Inclined surface, θ, θ1... inclination angle, θa, θ1a... reverse inclination angle. 2nd mouth base

Claims (2)

[Claims] (1) The butt end of one of the veneers to be vertically stripped is cut from the first inclined surface, vertical surface, and second inclined surface in a step-like manner extending a predetermined distance from the end edge where the back surface and the butt surface intersect toward the front surface. A second step-shaped second veneer is formed by cutting into a joint surface, and the end portion of the other veneer can be brought into close contact with the joint surface over a predetermined distance from the end edge where the front surface and the end surface intersect toward the back surface. A method for vertically splicing veneers, characterized by cutting and forming a joining surface consisting of an inclined surface, a vertical surface, and a first inclined surface, and joining the end portions of both veneers by interposing an adhesive between both joining surfaces. . (2) The method for longitudinally splicing a veneer according to claim (1), wherein the vertical surface of each joint surface is cut into a reversely inclined surface.