JPH0132043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for repairing raw wood for veneer lace, and its purpose is to provide a method for repairing raw wood for veneer lace that reliably repairs and reinforces cracks on the end surface. As a result, the aim is to streamline the veneer processing process after veneer lace at plywood factories.

Conventionally, when a veneer is cut using veneer lace from logs with cracks on the end surface, the veneer tends to tear from the cracks, and the veneer is divided into smaller pieces at the plywood factory due to the cracks. This is a major obstacle to streamlining the veneer processing process.

Therefore, an attempt was made to prevent the veneer from tearing by applying a crack-preventing coating to the end of the raw wood in advance to strengthen it and prevent the veneer from tearing. It is proposed by the official gazette). This method involves filling the cracks at the end of the log with adhesive or an adhesive containing wood flour, or forming a crack-preventing coating made of adhesive or film on the end surface of the log for reinforcement. It is extremely difficult to fill the crack deeply with the agent, and the only way to strengthen the joint is in the vicinity of the crack entrance. The adhesive strength of normal adhesives tends to be inversely proportional to the thickness, so if the gap between the cracks is wide, the adhesive layer used to fill it will become thicker, reducing the adhesive strength and causing bending during veneer cutting, etc. The reinforcing strength is extremely low because it is easily peeled off from the crack surface or destroyed internally due to deformation such as compression. Similarly, the crack prevention coating formed on the end surface of logs becomes more expensive as it becomes thicker in order to provide reinforcing strength or rigidity. There is a limit to the reinforcement strength because the cracks are more likely to separate or break internally, and what is especially disadvantageous is that the wider the cracks are, the more easily the veneer deforms when cutting. Since there is a high risk of breakage, the reinforcement strength is not stable and the reinforcement cannot be trusted. In other words, it can be somewhat helpful in preventing new cracks only if it is an extremely thin veneer that does not undergo much deformation during grinding, such as a veneer, and if it is treated with extreme respect after being cut. It was of low practical value.

The present invention aims to provide a method for repairing raw wood for veneer lace that is extremely excellent in repair and reinforcement without reducing reinforcement strength due to deformation during veneer cutting, etc. The present invention is illustrated in the drawings below. The following is an explanation based on an example of implementation.

The method for repairing logs for veneer lace according to the present invention is shown in FIG. 1 as a perspective view and as shown in FIG. Then, by pressing an appropriately shaped butt against the end face 2 of the raw wood 1, the sides of the crack 3 are forcibly pressurized locally, and the sides of the crack 3 are plastically deformed, thereby sealing or nearly sealing the crack 3. After the crack is closed, or if necessary, the crack is dried, and the adhesive 5 is applied to the end surface 2 including the crack 3 to impregnate it. Further, after drying as necessary, the adhesive 5 is applied and impregnated only on the crack surface or on the end surface 2 including the crack 3 and the crack surface, and the same procedure as described above is carried out until the adhesive 5 hardens. The crack 3 may be closed by a forced pressure device. Furthermore, the adhesive 5 may be applied and impregnated only on the cracked surface, the crack is closed, and then the adhesive 5 may be applied and impregnated onto the butt end surface 2 including the crack 3.

As described above, the crack 3 on the end surface of the log 1 is closed in a sealed or nearly sealed state by local plastic deformation of the crack side portion 4 due to pressure, and at least the crack surface 3a, 3b or the end surface 2 including the crack 3, an adhesive 5 such as a wet curing adhesive, a thermosetting adhesive, or a thermoplastic adhesive is applied and impregnated. As is clear from the figure, the amount of adhesive 5 interposed between the crack surfaces 3a and 3b due to the closure of the crack 3 is extremely small; in other words, the layer of adhesive 5 is extremely thin, so the bonding strength is extremely strong. Moreover, even when cutting the veneer 7 with the veneer lace knife 6, deformation such as bending or compression is unlikely to occur, and the softening effect due to local plastic deformation of the crack sides 4 is also added, making the crack surface No peeling or internal destruction occurs. Therefore, the veneer 7 does not tear from the crack 3 and can be cut into a continuous strip, so that the veneer processing process after veneer lace in a plywood factory can be dramatically streamlined.

In addition, the adhesive 5 applied and impregnated on the butt end surface 2 increases the anchoring effect by promoting permeation due to the local plastic deformation of the crack sides 4, resulting in extremely strong adhesion, as well as closing the crack 3 and preventing cracks. Since intensive deformation is eliminated due to the softening effect of the side portions 4, there is no peeling from the butt end surface 2 or internal destruction, and an extremely effective reinforcing effect is exhibited to prevent the veneer 7 from tearing.

Although the logs used in plywood factories are roughly cylindrical in shape, the reason why the plywood industry is called a labor-intensive industry is because the veneer is divided into pieces due to tearing. The main reason for this is the complexity of the process due to the increase in the number of sheets to be processed, and the effect of forming continuous strips of veneers according to the present invention is extremely large.

The width of the side portions of the crack to be plastically deformed may be determined as appropriate depending on the width of the gap between the cracks, but it is preferable that the crack be located approximately in the center since deformation can be easily closed. Also, if the width of the adhesive applied and impregnated on the butt end surface is within the width of the butt end surface on the side of the plastically deformed crack, it will not be cut off even when the veneer lace is trimmed. By applying veneer lace, it is possible to accurately form the end of the veneer.On the other hand, if the entire end surface of the log is coated and impregnated, no kerging will be possible, but the formation of new cracks will be prevented. Since the desired effect is produced, it is preferable to set it appropriately as necessary.

As described above, the present invention provides a method for repairing logs for veneer lace that can perform strong repairs and reinforcements with a small amount of adhesive, and thus contributes greatly to the development of the plywood industry.

[Brief explanation of drawings]

The drawings show an example of the implementation of the present invention, and FIG. 1 is a perspective explanatory view, and FIG. 2 is a partially enlarged view of section A in FIG. 1. 1... Log, 2... Wood end, 3... Crack, 4...
...crack side, 5...adhesive, 7...veneer.

Claims (1)

[Claims] 1. Pressure is applied to the sides of the crack on the end surface of the raw wood to cause plastic deformation, thereby sealing the crack in a sealed or nearly sealed state, and then applying and impregnating the end surface including the crack with an adhesive. A distinctive method for repairing logs for veneer lace.