JPH09123107A - Manufacture of plywood having less strain - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plywood having less strain than in a conventional plywood by using veneers having intersecting grains therein obtained by machining a low quality raw lumber, by properly adapting a difference in local parts or the whole faces of a pair of veneers, located at symmetric positions in the thickness direction of a plywood, of contracting direction or of contracting rate to a main cause of strain of the veneers. SOLUTION: A top face veneer 11 and a rear face veneer 12 having intersecting grains arranged at nearly the same positions and having the same thicknesses are arranged symmetrically with respect to the center in the thickness direction of a plywood A to be formed and adhered to a core veneer 13 through an adhesive. The four peripheries are cut and aligned to optional dimensions as necessary, so that the pair of veneers at the symmetrical positions with respect to the center in the thickness direction form a three-layer plywood A in which the intersecting grains are aligned at almost the same positions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plywood with less distortion and a method for manufacturing the plywood.

[0002]

2. Description of the Related Art Conventionally, plywood is formed by stacking a plurality of veneers of the same thickness or different thicknesses cut from raw wood (mainly southern seawood) selected as a plywood application material and cut to the required dimensions. In this case, the thickness and the general fiber direction of one or more pairs of veneers to be symmetrically positioned with respect to the center in the thickness direction of the plywood are matched with each other ( Generally, an odd number of veneers are used in an array configuration in which the fiber directions are sequentially crossed.) Considering that the neutral plane is set at the center in the thickness direction of the plywood, the grain (orientation of the fibers)
Regarding, no consideration is given to whether there is no effect on the quality of the product because veneers are cut from raw wood selected as plywood application material. In addition, the selection of the plywood-applied material and the unsuitable plywood material is performed, for example, at the time of logging, unloading, unloading, etc., in light of empirical rules, etc. Or, it is a fact that it is left without being shipped or is used for other uses such as lumber. Factors for selecting this log as a plywood-applied material and an unsuitable plywood material are listed as follows: the presence or absence of components that cause adhesion failure, ease of drying, difficulty in odor, and the presence of odors. An even bigger factor is whether or not at least some of the fibers are significantly non-straight, and such logs are conventionally used as plywood materials and generally have substantially straight fibers. In comparison with high-quality raw wood), turning resistance and bending stress are large, and when turning with conventional veneer lace, the surface of veneer is likely to be rough.
Its use is shunned. However,
With the depletion of wood resources in recent years, it is no longer possible to ignore a log of which at least some of the fibers are extremely non-rectile (hereinafter referred to as low-quality log), and it is necessary to make effective use of the log. Is increasing. Therefore, the applicant of the present invention has previously proposed "Veneer lace" (Japanese Patent Publication No. 56-16729), "Veneer lace" (Japanese Patent Publication No. 59-19007) or "Rotary race" (Japanese Patent Publication No. 61-218).
No. 05), a part or all of the power required for cutting the raw wood is effectively supplied from the outer periphery of the raw wood, and the boundary between the raw wood and the veneer is appropriately pressurized. By developing a revolutionary outer peripheral drive type veneer lace configured so as to enable the turning of the low-quality raw wood as described above, the effect of improving the degree of utilization has been achieved.
However, as utilization has increased, new problems with plywood quality have become apparent. That is, the veneer of veneer cut from low-quality raw wood is, of course, non-straight, non-traffic straight-grain collectively referred to as so-called mating grain, and more specifically, mainly on oblique grain, There is an inherent grain in which interlaced grain and wavy grain are mixed in various ways, but if such veneers are randomly combined and adhered as before, the plywood will warp or undulate locally or entirely. Such distortion is liable to occur, and the inconvenience of deteriorating the quality of the plywood is scattered to the extent that there is a practical problem, so that the value as a veneer is extremely low. Therefore, in the development process of the present invention, a large number of experiments and verification based on the experiments were repeated to try to find out the cause of the distortion, but it was not necessarily possible to elucidate the entire contents. Actually, it is considered that incentives other than the incentives described below are acting in combination, and further improvement is desired in order to completely suppress the generation of distortion, but at least the incentives described below must be appropriately dealt with. For example, it has been confirmed that the occurrence of distortion can be effectively suppressed as compared with a conventional plywood employing a random combination. Therefore, the incentives that have been elucidated first will be described below. The veneer is relatively tough in the fiber direction, and is strong against external forces such as compression, tension, and bending.
It is very soft in the direction perpendicular to the fiber, for example, it expands and contracts only in the direction perpendicular to the fiber due to the amount of water content, for example, as is known to be a unique material having remarkably anisotropy. In the case where there is an implicit grain,
Since the direction of expansion and contraction differs from part to part (strictly on both sides), it is natural that distortion occurs when expanding and contracting due to various factors, and such a characteristic is a major cause of plywood distortion. Needless to say. Therefore, in order to remove the incentive, it is not impossible to change the above properties by directly applying chemicals to the veneer, but doing so is not practical in terms of economy and also in view of the gist of the present invention. For the sake of convenience, a detailed description of the distortion of the veneer itself will be omitted here. Heretofore, conventionally, in the production of plywood, a synthetic resin such as urea resin, melamine resin, phenol resin, or the like, or a thermosetting adhesive mainly composed of a modified resin, a co-condensation resin, a mixed resin, or the like is often used. Have been.
These adhesives contain a large amount of solvent such as water (the solvent of most adhesives is water, for example, the water content of the most frequently used urea resin adhesive reaches 35 to 55%, There are some adhesives that use alcohol as a solvent) It is manufactured and marketed in liquid form, and if necessary, a solvent such as water, an extender such as wood flour and wheat flour, and a curing agent such as ammonium chloride. , Or other additives such as fillers, thickeners, plasticizers, etc. are blended and applied to the adhesive surface of appropriately dried veneers, then laminated with other veneers and then cured by hot pressing. The form of use is set. Then, the solvent is partially absorbed together with a part of the adhesive into the veneer, and the remaining solvent is sequentially diffused from the adhesive with heating for curing the adhesive. Therefore, the adhesive is cured while being significantly contracted. Of course, the veneer itself also swells once with the adhesion of the adhesive and then dries and shrinks with the heating when curing the adhesive, so there are elements that follow the contraction of the adhesive,
Due to the anisotropy, the following direction is limited to the direction orthogonal to the fiber, and there is also secondary swelling due to absorption of the solvent that is diffused, so that it completely follows the contraction of the adhesive. Is virtually impossible. As a result, a large compressive force due to the contraction of the adhesive acts on the veneer. Therefore, the veneer having anisotropy is slightly reduced mainly in the direction orthogonal to the fiber, but at this time, as described above, it is symmetric with respect to the center of the plywood in the thickness direction. Even if it is considered that the thickness and the approximate fiber direction of the pair of veneers arranged at different positions are matched for each pair, and the neutral plane is set at the center of the thickness direction of the finished plywood. It will be easily understood that the plywood will be distorted if there is a difference in the reduction direction or the reduction ratio between one surface layer side and the other surface layer side with respect to the plane. Therefore, referring to the factors that cause a difference in the shrinking direction or the shrinkage ratio between the one surface layer side and the other surface layer side centering on the neutral surface, the compressive force accompanying the shrinkage of the adhesive agent and the adhesive (solvent )
The swelling / shrinking of the veneer itself due to the absorption and divergence of the veneer can be considered to be almost equal on both surface layers, and both sides of the veneer including the neutral surface (in the case of a combination of odd number of sheets) can be considered. Since the difference in the reduction direction and the reduction ratio for each local portion is also small, the difference in the reduction direction or the reduction ratio over the local portion or the entire surface of the pair of veneers at the symmetrical position in the thickness direction of the plywood is ultimately small. It is mainly the cause of distortion. By the way, the veneer turned from the high-quality raw wood is almost entirely straight through the grain (see Reference Photo 1), and the reduction direction is almost constant over the entire surface. Therefore, even if they are randomly combined,
The reduction direction of the pair of veneers at symmetrical positions with respect to the center of the thickness direction is almost constant over all, and the reduction ratio is also almost uniform along with it. There is no risk of inducing distorting strain. However, with regard to veneers turned from low-quality raw wood, the shrinking direction at the crossing grain part differs locally, so with a random combination, it is symmetrical with respect to the center in the thickness direction. Since the reduction directions of the pair of veneers located at different positions are different over the local area or over the entire area (corresponding to the mating grain), the reduction ratio is also different over the local area or over the entire area. This results in distortion occurring locally or over the entire surface of the plywood. The present invention appropriately responds to the above-mentioned incentives, and uses a veneer having an interlaced grain turned from a low-quality log to develop a plywood with less distortion than conventional ones. In the method for producing a veneer of No. 1, it was found during the development process of the present invention that a pair of standard length veneers used for appropriately responding to the incentive cannot be effectively obtained. We have also developed a method for cutting raw wood that is effective for obtaining. That is, the structure of the present invention, at least a pair of veneers at symmetrical positions in the thickness direction of the plywood, plywood with less distortion, characterized by aligning the mating grain in almost the same region, Forming plywood by arranging at least a pair of standard length veneers in which the mating wood grain, which is the method of manufacturing plywood, is aligned in almost the same area, is placed symmetrically with respect to the center in the thickness direction of the resulting plywood. A method of manufacturing plywood with less distortion, which is characterized in that, of the manufacturing method, among at least a pair of standard length veneers in which the crossing grain is aligned at substantially the same portion, further an arbitrary number of pairs of A method for producing plywood by specifying a method for cutting a standard-sized veneer, a thick band-shaped veneer having a thickness twice as much as a desired thickness from a cylindrical raw wood in which at least a part of fibers are remarkably non-rectified. By turning and then cutting the thick strip-shaped veneer into a predetermined size, it has twice the desired thickness. A method for producing a plywood with less distortion, which comprises forming a standard veneer and then dividing the thickness standard veneer into two in the thickness direction, and the at least one pair of standard veneers. Is a method for manufacturing plywood that further specifies the method for cutting an arbitrary number of pairs of standard-sized veneers. At least some of the fibers are remarkably non-rectangular, and the thickness is twice the desired thickness. The strip-shaped veneer having the thickness of 1 is turned, and the strip-shaped veneer is further divided into two in the thickness direction to form two strip-shaped veneers having a desired thickness. A method for manufacturing a plywood with little distortion, which is characterized in that the strip-shaped veneers are formed by cutting each band-shaped veneer in a substantially uniform manner, and a method for manufacturing the same number of pairs of standard-sized veneers in a turning direction. At least some of the fibers are remarkably marked by using two cutting blades that are properly separated from each other. Two strip-shaped veneers of desired thickness are overlapped and turned from a straight columnar log, and then the existing lathes are aligned in almost the same area and each strip-shaped veneer is cut into a predetermined size. A method for producing a plywood with less distortion, which is characterized by being formed by using a notch-forming member, in which the above-mentioned arbitrary number of pairs of standard-sized veneers are used, and at least some of the fibers are markedly non-circular. The step of forming a notch having a depth twice the desired thickness in parallel with the axis of rotation of the raw tree for each predetermined dimension in the outer peripheral direction of the columnar raw tree, and two sheets provided with an appropriate distance in the turning direction. Using a cutting tool,
A method for producing a plywood with less distortion, which is characterized in that the step of overlappingly turning two standard-sized veneers having a desired thickness from the cut raw wood is alternately repeated. , And for the reasons described below,
We also propose a method of manufacturing a plywood by arranging a pair of semi-dried or undried fixed-length veneers in which the cross grain is aligned at almost the same position on the outermost layer of the plywood.

[0003]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in further detail below with reference to an embodiment illustrated in the drawings. However, the actual grain is extremely fine and complicated (see Reference Photos 2 to 4), and it is difficult to realistically display the grain on the entire surface of the veneer. The annual ring pattern normally used when indirectly displaying various fiber directions is displayed instead. More specifically, there is not always a certain correlation between the annual ring pattern that appears prominently on veneers that are turned from conifers and the like and the pseudo annual ring pattern that appears on veneers that are turned from southern timber. There is no relation, but it will be easily understood that, at least if the annual ring patterns match, the grain also matches. The method of manufacturing a plywood according to the present invention is, for example, as illustrated in FIGS. 1, 2, and 3, for a front veneer 11 and a back veneer 11 having the same thickness in which the cross grain is aligned in substantially the same portion. The veneer 12 and the resulting plywood A are arranged symmetrically with respect to the center of the thickness direction,
By adhering to the central core veneer 13 via an adhesive, and cutting the four circumferences to an arbitrary size if necessary, a pair of veneers at symmetrical positions with respect to the center in the thickness direction, A three-layer plywood A is formed by arranging crossing grain in almost the same region. In the figure, XX is a center line indicating the center of the plywood A in the thickness direction, and 11a and 12a are conduits. is there. The three-layer plywood A configured as described above is different from the neutral plane even if the shrinking directions of the local veneer 11 and the rear veneer 12 are different due to the existence of the cross grain. Surface veneer 11
Since the shrinking direction for each local part of the back single plate 12 is substantially uniform, and the shrinking ratio is also substantially uniform accordingly, it is possible to use a conventional three-layer plywood in which random combinations are adopted. By comparison, the occurrence of distortion is significantly suppressed, and there is almost no risk of deterioration in quality that causes problems in practical use, which is effective. The plywood stacking mode to which the present invention is applied is not limited to the three layers as in the above-mentioned embodiment, but may be an ordinary odd number of layers of 5 or more, for example, as illustrated in FIG. The part corresponding to the normal single-layer core is
Plywood B having an even number of laminated layers (4 in the embodiment) formed by two single plates having the same thickness with the fiber directions aligned in the same direction, or adjacent to each other, for example, as illustrated in FIG. In addition to the ordinary mode, a plurality of arbitrary pairs (in the embodiment, two pairs located outside the core single plate) are bonded together with the fiber directions aligned in the same direction. There is a mode, and the point is that all pairs of veneers arranged at symmetrical positions with respect to the center of the plywood in the thickness direction so that the neutral plane is determined at the center of the plywood in the thickness direction, as usual. As long as the plywood has a structure in which the thickness and the schematic fiber direction of each other are matched for each pair, there is no particular limitation on the laminated mode including the number of laminated layers, and the thickness of each veneer is also different from the conventional one. Of course, a similar error is allowed. Further, in order to suppress the strain caused by the above-mentioned factors as much as possible, regardless of the stacking mode, all pairs of veneers in a symmetrical position with respect to the center of the plywood in the thickness direction are It is desirable to arrange the crossing grain in almost the same part,
It is not always necessary to configure all pairs of veneers identically in this way, the point is that among the veneers of a pair located symmetrically with respect to the center of the plywood in the thickness direction, If any pair of veneers have the same crossing grain in almost the same region, it is effective because the distortion is reduced on average as compared with the case where a completely random combination is adopted. Usually, the veneer is dried to a water content of about 5 to 15% and then formed into plywood. However, a veneer with an interlaced grain that has been turned from a low quality raw wood is used for comparison using a roll dryer or the like. If it is dried while being gently restrained, distortion, tearing, chipping, etc. occur, which is a practical problem. For example, the “method for drying a single plate” previously filed by the present applicant (Japanese Patent Publication No. 61-32591). "Veneer heating device"(JP-B-61-45150)-"Veneer veneer drying device" (JP-A-63-46375) or "Veneer veneer drying device" (JP-A-SHO) 63-91477), etc., it is possible to dry using a drying device of a type that relatively firmly restrains a single plate with a wide surface or as many points as possible. preferable. However, in particular, the veneer used for the outermost layer of plywood needs to be relatively thin in order to obtain a smooth surface, and ideal drying that does not cause distortion, tearing, chipping, etc. even with the drying device of the above type Since it is difficult, an attempt was made to carry out adhesion in a semi-dried or undried state with a water content of 35% or more, which is not usually carried out. It was confirmed that they could be bonded without any trouble. This can be said to be an extremely effective means as one means for avoiding the difficulty of drying a thin veneer having a cross grain. However, according to the random combination, the strain caused by the difference in the drying shrinkage of the veneer itself due to the heating at the time of bonding is remarkable, which is not practical, but the veneer used for the outermost layer is By adopting a configuration in which the crossing grain is aligned in almost the same area, the drying shrinkage of the veneer itself due to heating during bonding is almost counteracted over the entire surface on both sides of the neutral plane, and the occurrence of distortion is avoided. Since it is practical, and the semi-dried or undried veneer is flat with almost no shrinkage, it was relatively easy to align the crossing grain at the same site. However, if a semi-dried or undried veneer comes into contact with iron and reacts with it, the surface will become black and contaminated, so the material of the heating plate used to cure the adhesive is non-reactive, such as stainless steel or aluminum. In order to average the drying shrinkage of the veneer itself, it is necessary to disperse a large number of sharp microstabs rather than pressing with a heating plate having a normal flat heating surface. It was effective to use a heating plate having a heating surface projecting in the shape of a plate and to bite the fine puncture body into the veneer so as to regulate the drying shrinkage of the veneer itself and apply heat and pressure. Further, it is well known that if the veneer is subjected to so-called tenderizing treatment for forming fine cracks or cuts, the flexibility and stretchability of the veneer are increased. For a pair of veneer that aligns with the same part and other veneers, various methods of tenderizing treatment can be applied before or after drying or when bonding with semi-dry or undried as described above. When applied and dried, they were all effective in reducing strain, but when applied before drying, if the intervals between cracks or cuts were wide, they would expand due to drying shrinkage, and Since there is a risk that the quality of the board and the plywood may be impaired, it is desirable to make the distance as small as possible. Next, a method for obtaining a pair of standard length veneers in which the above-described cross grain is aligned in almost the same region will be described. Of course, such a pair of standard length veneer,
Not only the so-called one-piece veneer as in the above embodiment, but a narrow veneer cut from an outer peripheral portion of an irregularly shaped raw wood or the like to be joined to a required standard length, the point is that the crossing tree is essential. Although it is sufficient if the reasoning is aligned in almost the same area, the method of making a narrow single plate to the required standard length is extremely complicated, inevitably costly, and not suitable for mass production. Is. On the other hand, in the normal veneer creation method, it is possible to accidentally acquire the outer circumference length of the raw wood during the cutting process, which is approximately an integral multiple of the required standard length, except in rare cases. It cannot be acquired effectively. In other words, if the outer circumference of the raw tree is less than the required standard length, it is not possible to obtain a pair of standard length veneers naturally, and conversely Even if it is longer than the standard length, if it is an integer multiple or less of the required standard length, or less, a residual narrow veneer that obtains the desired pair of standard length veneers will occur, resulting in a large amount of waste. become. Therefore, the conventional method for producing a veneer lacks practicality, and it is impossible to obtain an effective pair of standard-sized veneers. Therefore, the inventor of the present application has newly developed a method for producing a single plate, which will be described in detail below. That is, one of the methods for producing a pair of standard length veneers according to the present invention is, for example, as shown in FIG. 6, a large number of piercing bodies 2 at appropriate intervals in the axial direction.
1, a peripheral driving member 22, a divided pressing member 23,
Using a known outer peripheral drive type veneer race 2 equipped with a cutting blade 24, a spindle 25, etc. (if necessary, a veneer having an arbitrary thickness is formed to temporarily transform an irregularly shaped raw wood into a cylindrical shape. Through the process of forming into) columnar low quality log 1
After turning a thick strip-shaped veneer 14 having a thickness twice as much as the desired thickness, a known cutting provided with a cutting blade 32 having a rotating shaft 31, a blade receiver 34 having an elastic body 33 and also serving as a transport roll. Using the device 3, the thick strip-shaped veneer 14 is cut into a predetermined size, and a thickness-regular veneer 15 having a thickness twice the desired thickness is cut.
And then a large number of piercing bodies 4 are formed at appropriate intervals in the axial direction.
1 and the elastic member 42 are alternately arranged, a conveying member 43, a plate-shaped regulating member 44, a cutting blade 45, and the like are used to cut the thickness standard veneer 15 in the thickness direction 2. By dividing, the pair of standard length single plates 16 and 17 are created. According to such a producing method, the mating grain of each standard length veneer is accurately aligned in the same region, and a pair of standard length veneers can be efficiently acquired, which is practical. As a matter of course, if necessary, the step of dividing the thickness standard veneer into two in the thickness direction may be separated from the step of forming the thickness standard veneer at a different time (for example, the thickness standard veneer through a drying device). It is also possible to perform it after semi-drying the veneer), or to perform the step of once forming an irregularly shaped log into a column shape in another veneer lace, including the case of other production methods described later. It doesn't matter. Further, another one of the methods for producing a pair of standard length veneers according to the present invention is a method in which some of the steps of the above-mentioned production method are rearranged, and for example, as shown in FIG. After turning a thick strip-shaped veneer 14 having a thickness twice the desired thickness from the cylindrical low-quality log 1 using the outer peripheral drive type veneer lace 2, a large number of piercing bodies are arranged at appropriate intervals in the axial direction. The thick strip-shaped veneer 14 is divided into two parts in the thickness direction by using a cutting device 5 including a pair of upper and lower conveying members 52 having 52, a pair of upper and lower divided regulating members 53, and a cutting blade 54. To form two strip-shaped single plates 18 and 19 of desired thickness,
Then, the existing mating wood grains are aligned in almost the same region, and each of the strip-shaped veneers 18 and 19 is cut into a predetermined size by using the above-mentioned known cutting device 3, whereby a pair of fixed-length veneers 16 is cut.
17 is produced, and a pair of standard length veneers can be efficiently obtained by such a producing method. Incidentally, when cutting each strip-shaped veneer into a predetermined size, if the two are laminated and cut together as in the above-mentioned embodiment, it is relatively easy to align the positions of the mating grains, which is convenient. Although not necessarily limited to the configuration, although not shown, the operation timing of each cutting blade is electrically or mechanically (a cutting line is set so that the grain is almost the same). Each band-shaped veneer may be separately cut into a predetermined size by using two synchronized cutting devices, and if necessary, each band-shaped veneer may be cut, for example, in the rear part of the cutting device 5. After the plates are separately wound up, as shown in FIG. 9, each strip-shaped single plate 18, 19 is placed at an arbitrary place.
Are simultaneously unwound from the take-up shafts 6 and 6, and the strip-shaped single plates 18 and 19 are cut into predetermined pairs by using a known cutting device 7 having a movable blade 71, a fixed blade 72 and the like. It does not matter even if it takes the form of making the standard length single plates 16 and 17. In addition, as a feature common to the above two creation methods,
The dividing resistance required to obtain a standard-sized veneer or a band-shaped veneer having a desired thickness by dividing the thickness-constant veneer or the band-shaped veneer into two parts in the thickness direction is equal to that of the raw wood. It was confirmed that the cutting resistance required to obtain a plate or band-shaped veneer was somewhat less. Therefore, it is possible to make the cutting edge angle of the cutting blade sharper than the cutting edge angle of the cutting tool of the veneer lace. Therefore, when a pair of standard length veneers is used as the outermost layer of plywood, it is convenient to bond the divided cross-sections toward the surface of the plywood. Furthermore, another one of the methods for producing a pair of standard length veneers according to the present invention is, for example,
As illustrated in the drawing, the outer peripheral drive member 22, the pressing member 23,
In addition to the cutting blade 24, the spindle 25, and the like, another cutting blade 24a that moves in the centering direction of the log in synchronization with the cutting blade 24 at a position appropriately separated from the cutting blade 24 in the turning direction. , A peripheral type driving member 22a having a large number of piercing members 21a, a compound type peripheral type driving veneer race 8 having a divided pressing member 23a, etc. The plates 18 and 19 are turned in an overlapping manner, and then two known cutting devices 3 are used so that the lathes of the strip-shaped veneers 18 and 19 are matched to each other.
By electrically or mechanically synchronizing the operation timing of the cutting blade 32 of No. 1, each pair of strip-shaped single plates 18 and 19 is cut into a predetermined size to form a pair of fixed-length single-plates 16 and 17. Even with such a production method, a pair of standard length veneers can be efficiently obtained. Incidentally, as in the above embodiment,
It is structurally convenient if another cutting blade 24a is provided on the side directly opposite to the cutting blade 24, but it is not necessarily limited to that structure, and the point is that the strip-shaped veneer is duplicated. It is sufficient if it can be turned, and another cutting tool 24a for cutting
The feed mechanism for moving the (peripheral drive member 22a, the pressing member 23a) may be the same as the feed mechanism for the cutting tool 24, but in any case, the movement amount of each feed mechanism per one rotation of the raw wood is set to the desired thickness. It is necessary to set it to twice as large as the band-shaped veneer. Of course, if necessary, in the rear part of the veneer lace 8, after individually winding each strip-shaped veneer, the strip-shaped veneers 18 and 19 are placed at arbitrary places as illustrated in FIG. At the same time, rewind from the take-up shaft 6 ・ 6,
By using the known cutting device 7, each strip-shaped single plate 18, 19 is cut into a predetermined size, thereby forming a pair of fixed-length single plates 16.
It does not matter even if it takes the form of creating 17. Furthermore, another one of the methods for producing a pair of standard length veneers according to the present invention is, for example, as shown in FIG. 10, in addition to a single plate-shaped pressing member 23b, a cutting blade 24, a spindle 25, and the like. , A multiple spindle drive provided with another cutting blade 24a, a pressing member 23c, etc., which is moved in the turning direction in synchronization with the cutting blade 24 at a position appropriately separated from the cutting blade 24 in the turning direction A circular veneer race 9 is further provided with a circular saw-shaped notch forming member 10 that is movable in both the axial direction of the log and the centripetal direction of the log, and a rotary guide member 20 that regulates the cutting depth of the notch forming member 10. The notch forming member 10 forms a notch 30 having a depth twice the desired thickness along the rotation axis of the low-quality log 1 at each predetermined dimension in the outer circumferential direction of the column-shaped low-quality log 1. And the cutting blade 2 The step of overlappingly turning two low-quality logs 1 and 16 of the standard thickness veneers 16 and 17 having a desired thickness from the low quality wood 1 having the cuts 30 is alternately and intermittently repeated by 24a. Although it is slightly inferior to the above three cutting methods, a pair of standard length veneers can be obtained in which the mating wood grain is accurately aligned in the same region as in the first cutting method. . In the case of obtaining a pair of standard length veneers used for parts other than the outermost layer, there is no practical problem even if the notch is slightly deeper, and the notch forming member has the same shape as the circular saw as in the above embodiment. The shape is not limited to the shape, and even if the fiber is simply cut, such as the cutting blade 32 of the cutting device 3, the point is that, for each predetermined dimension in the outer peripheral direction of the low-quality raw wood,
It suffices that a cut having a depth twice the desired thickness can be formed along the axis of rotation of the low-quality raw wood, and further regarding the disposition position of another cutting blade, the configuration of the feed mechanism, and the like. It does not matter according to the description of the double peripheral drive type veneer lace used in the above-mentioned manufacturing method. Of course, in any cutting method, the devices to be used are not limited to the types illustrated in the embodiments, and for example, the veneer lace, the cutting device, the cutting device, etc. illustrated in the respective embodiments can be used before and after the device. It is possible to replace each other within the range that does not impair the function of the device, or to replace with other known types, and the shapes of the members in each device are appropriately designed within the range that does not impair the function. You can change it. Also, as the low-quality raw wood to be symmetrical, not only the conventionally used heavily used South Sea timber, but for example, general conifers have a generally straight grain, but especially for knots and node rotation, It is well known that the reason is extremely non-obvious, and low quality logs of all tree species including these are made symmetrical.

[0004]

As is clear from the above, the plywood according to the present invention has less distortion on average as compared with the plywood manufactured by randomly combining the intersecting grain of the single plates. Further, the plywood manufacturing method according to the present invention, it is possible to manufacture a plywood with less distortion as described above, as a result, it is effective because the utility value of veneer that is turned from poor quality raw wood is improved. is there. Furthermore,
If a pair of standard length veneers used in the method for manufacturing the plywood is cut as in the present invention, in any case, regardless of the length of the outer circumference of the raw wood, it is possible to obtain a desired large amount without waste from the low quality raw wood. A pair of standard length single plates can be obtained, and the manufacturing cost thereof is low, which is extremely convenient.

[Brief description of the drawings]

The drawings are for explaining the present invention. FIG. 1 is a process explanatory view illustrating the steps of the method for manufacturing a plywood according to the present invention, and FIG. 2 is a partial enlargement of part a in FIG. Fig. 3 is a partially enlarged view of a portion b in Fig. 1, Figs. 4 and 5 are side explanatory views of another embodiment of the plywood according to the present invention, Figs. 8 and 10 are process explanatory diagrams illustrating the steps of the method for producing a pair of standard length veneers according to the present invention, and FIG. 9 is a process explanatory diagram illustrating the rewinding process.

[Explanation of symbols]

A, B, C: plywood, XX: center line indicating the center in the thickness direction of plywood, 1: low-quality log, 11a, 12a
... Conduit, 11 ... Front single plate, 12 ... Back single plate, 13 ... Core single plate, 14 ... Thick strip single plate,
15: Thickness standard veneer, 16, 17 ... Standard size veneer, 1
8, 19 ... Strip-shaped single plate, 2 ... Peripheral drive type veneer lace, 21, 21a ... Puncture body, 22, 22a ...
Peripheral drive member, 23, 23a, 23b, 23c ... Pressing member, 24, 24a ... Cutting blade, 25 ... Spindle, 3 ... Cutting device, 31 ... Rotating shaft, 32
... Cutting blade, 33 ... Elastic body, 34 ... Blade receiver,
4 ... Cutting device, 41 ... Piercing body, 42 ... Elastic body, 43 ... Conveying member, 44 ... Restricting member, 45 ...
.... Scissor blades, 5 ... Severing devices, 51 ...
2 ... Conveying member, 53 ... Restricting member, 54 ... Dividing blade, 6 ... Winding shaft, 7 ... Cutting device, 71 ...
Movable blade, 72 ... Fixed blade, 8 ... Compound outer peripheral drive type veneer race, 9 ... Compound spindle drive type veneer race, 10 ... Notch forming member, 20 ... Guide member, 30 ...・ Notch

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[Procedure amendment]

[Submission date] February 9, 1996

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsuruta Matsunaga 13-3, Kamiimaike, Morioka, Higashiura-machi, Chita-gun, Aichi Prefecture (no address)

Claims (7)

[Claims] 1. A low-distortion plywood characterized in that at least a pair of veneers at symmetrical positions with respect to the center of the plywood in the thickness direction align the crossing grain in substantially the same region. . 2. A plywood is formed by arranging at least a pair of standard length veneers in which the crossing grain is aligned in substantially the same area, at positions symmetrical with respect to the center of the thickness of the plywood to be formed. A method for manufacturing plywood with little distortion, which is characterized by the following. 3. A pair of standard length veneers among said at least a pair of standard size veneers are semi-dried or undried veneers, and these semi-dried or non-dried veneers can be completed. The method for producing a plywood with a small strain according to claim 2, wherein the plywood is arranged so as to be located on the outermost layer of the plywood. 4. An arbitrary number of pairs of standard-sized veneers among the at least one pair of standard-sized veneers are prepared, and at least a part of the fibers is remarkably non-rectified from a columnar raw wood to have a thickness twice the desired thickness. The thick strip-shaped veneer having a thickness of 10 mm is turned, and the thick band-shaped veneer is cut into a predetermined size to form a thickness standard veneer having a thickness twice the desired thickness. The method for producing plywood with less distortion according to claim 2 or 3, characterized in that it is formed by dividing a standard length veneer into two in the thickness direction. 5. An arbitrary number of pairs of standard-sized veneers among the at least one pair of standard-sized veneers are prepared by doubling a desired thickness from a cylindrical raw wood in which at least some fibers are remarkably non-rectified. Turning a thick strip-shaped veneer having a thickness of, and further dividing the thick strip-shaped veneer into two in the thickness direction to form two strip-shaped veneers having a desired thickness,
Next, it is formed by aligning the existing mating wood grains in substantially the same region and cutting each strip-shaped veneer into a predetermined size, thereby reducing the distortion according to claim 2 or 3. Manufacturing method of plywood. 6. At least a part of the at least one pair of standard-length veneers is further provided with an arbitrary number of pairs of standard-length veneers, which are provided with two blades for cutting provided at appropriate intervals in the turning direction. The two strip veneers of the desired thickness are overlapped by turning from a column-shaped log of which the fibers are extremely non-straight, and then the existing cross grain is aligned in almost the same area to determine each strip veneer. The method for manufacturing plywood with less distortion according to claim 2 or 3, characterized in that the plywood is formed by cutting it into individual dimensions. 7. An arbitrary number of pairs of standard length veneers among the at least one pair of standard length veneers are formed into a columnar shape in which at least some of the fibers are remarkably non-rectified by using a notch forming member. For the step of forming a notch having a depth twice the desired thickness in parallel with the axis of rotation of the raw wood for each predetermined dimension in the outer peripheral direction of the raw wood, and for cutting two pieces provided at an appropriate distance in the turning direction With a knife,
The step of overlappingly turning two standard length veneers having a desired thickness from the raw wood having the notches is formed by intermittently repeating the steps alternately. The method for manufacturing plywood with less distortion according to item 3.