Veneer dehydration method and veneer dehydration system

A layered-up veneer board is formed by layering veneers up to a predetermined height such that the fiber directions of the respective veneers are alternately perpendicular to one another, and the layered-up veneer board is compressed by a compression device, to remove moisture contained in the veneers. Wood is a material in which the tensile strength in the fiber direction of the wood is higher than the tensile strength in the direction perpendicular to the fiber direction. With this layering scheme, even when stress is applied to the veneers and causes elongational deformation of these veneers as a result of compressing the layered-up veneer boards in the layering direction, elongational deformation of the veneers in the directions perpendicular to the fiber directions thereof can be reduced.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2018-137257, filed Jul. 20, 2018. The contents of that application are incorporated by reference herein in their entirety.

BACKGROUND

1. Field of the Invention

The invention relates to a veneer dehydration method and a veneer dehydration system for removing moisture contained in veneers.

2. Description of the Related Art

Japanese Patent Application No. 4783862 discloses a veneer dehydration method. In this veneer dehydration method, a layered-up veneer board, which is obtained by layering a plurality of veneers for plywood one above the other with the fiber directions thereof aligned, is loaded between a pair of upper and lower platens arranged facing each other, and then, of the side wall surfaces of the loaded layered-up veneer board, a pair of side wall surfaces extending along the fiber directions of the veneers is held by the restricting members which are installed on the lower platen so as to be able to protrude and retract. In this state, the upper and lower platens apply pressure to and compress the layered-up veneer board from above and below in the layering direction, to remove moisture contained in the layered-up veneer board.

According to this veneer dehydration method, when the upper and lower platens apply pressure to and compress the layered-up veneer board from above and below in the layering direction, the pair of restricting members restricts the plurality of veneers of the layered-up veneer board from stretching in the direction intersecting with the fiber directions (“fiber intersecting directions,” hereinafter) of the veneers. Therefore, cracking of the veneers in the fiber directions thereof, which is attributed to such stretching, can be reduced.

BRIEF SUMMARY

However, the veneer dehydration method described above needs to operate the pair of restricting members along with a conveyor carrying the layered-up veneer board and the upper and lower platens, making the control complicated. Furthermore, a mechanism for operating the pair of restricting members is required in addition to the pair of restricting members, resulting in a complicated, enlarged device. If the plurality of veneers constituting the layered-up veneer board have non-uniform dimensions in the fiber intersecting directions, some of these veneers would not be restricted by the pair of restricting members from stretching in the fiber intersecting directions, resulting in cracks in such veneers in the fiber directions thereof. Even when the dimensions of the plurality of veneers are uniform in the fiber intersecting directions, as long as there exist veneers with lathe checks (cracking caused due to the difference in dimensions between the inner and outer peripheries of a veneer when a rotary lathe thinly cuts a log into a veneer and deforms the resultant veneer into a flat shape), the pair of restricting members cannot restrict such veneers from stretching in the fiber intersecting directions, resulting in cracks in the veneers in the fiber directions. In terms of preventing cracking of veneers without complicating the control and device or enlarging the device, there is still room for improvement.

The invention was contrived in view of the foregoing circumstances, and an object thereof is to provide a veneer dehydration method and a veneer dehydration system which, while simply constructed, are capable of not only restricting a veneer from stretching in the direction intersecting with the fiber direction of the veneer, but also reducing cracking of the veneer attributed to such stretching.

The veneer dehydration method and the veneer dehydration system according to the invention adopt the following measures in order to achieve the object described above.

According to a preferred aspect of the veneer dehydration method of the invention, a veneer dehydration method for removing moisture contained in veneers is constructed. The veneer dehydration method has the steps of (a) forming a layered-up veneer board by layering a second veneer, which is positioned with a fiber direction thereof aligned with a second direction intersecting with a first direction, on a first veneer positioned with a fiber direction thereof aligned with the first direction, and (b) removing moisture contained in the first and second veneers by applying pressure to and compressing the layered-up veneer board from above and below in a layering direction.

The concept of the term “fiber direction” used herein literally includes not only the fiber directions of wood seen on the primary surfaces of veneers, but also extension directions of lathe checks (cracking caused due to the difference in dimensions between the inner and outer peripheries of a veneer when a rotary lathe thinly cuts a log into a veneer and deforms the resultant veneer into a flat shape) formed in the veneers. The terms “first veneer” and “second veneer” used herein favorably encompass not only a single sheet of veneer but also a veneer that is obtained by bringing tightly or closely together a plurality of narrow veneers with unnecessary parts removed, and then joining these narrow veneers into a single sheet by using a joining material such as a joining tape, an adhesive, or staples, and a veneer that is obtained simply by bringing tightly or closely together a plurality of narrow veneers with unnecessary parts removed.

According to the invention, cracking attributed to stretching of the first and second veneers in the directions intersecting with the fiber directions of the first and second veneers can effectively be reduced by a very simple configuration of using the anisotropy of the strengths of the veneers. Specifically, the tensile strength of a veneer in the same direction as the fiber direction of the veneer is higher than the tensile strength in the direction intersecting with said fiber direction, and therefore the veneer is more likely to stretch and become deformed in the direction intersecting with the fiber direction than in the same direction as the fiber direction. In view of this property inherent in veneers, when compressing the layered-up veneer board, the configuration in which the first and second veneers are layered with the fiber directions thereof intersecting with each other can favorably reduce stretching of the first veneer in the direction intersecting with the fiber direction thereof, due to the relatively high tensile strength in the fiber direction of the second veneer in frictional contact (static friction) with the first veneer. Furthermore, the configuration in which the first and second veneers are layered with the fiber directions thereof intersecting with each other can favorably reduce stretching of the second veneer in the direction intersecting with the fiber direction thereof, due to the relatively high tensile strength in the fiber direction of the first veneer in frictional contact (static friction) with the second veneer. The invention, therefore, can effectively reduce cracking of the first and second veneers which could be caused as a result of the first and second veneers stretching in the directions intersecting with the fiber directions thereof.

The first and second veneers may each include a square veneer which has a square shape when viewed from one side in a direction along the layering direction. The first and second veneers may also each include a rectangular veneer which has a rectangular shape when viewed from one side in a direction along the layering direction. The rectangular veneer may be formed to have a long side approximately twice as long as a short side.

According to another aspect of the veneer dehydration method of the invention, the step (a) forms the layered-up veneer board by alternately layering the first veneer and the second veneer.

According to this aspect, the effect of reducing stretching of the first and second veneers in the directions intersecting with the fiber directions thereof can be achieved on both front and rear surfaces of all of the first and second veneers constituting the layered-up veneer board, due to the relatively high tensile strengths in the fiber directions of the first and second veneers in frictional contact (static friction) with each other by the front and rear surfaces thereof. Thus, cracking attributed to stretching of the first and second veneers in the directions intersecting with the fiber directions thereof can be reduced more effectively. In regard to the first or second veneer disposed at the bottom and top of the layered-up veneer board in the layering direction, either the front or rear surface is restrained by a pair of platens for compressing the layered-up veneer board, preventing the first or second veneer from stretching in the direction intersecting with the fiber direction thereof.

According to yet another aspect of the veneer dehydration method of the invention, the step (a) forms a layered body by layering a pair of the second veneers on the first veneer, and forms the layered-up veneer board by layering a plurality of the layered bodies.

According to this aspect, in the relationship between the first and second veneers, stretching of the first veneer in the direction intersecting with the fiber direction thereof can be reduced by the relatively high tensile strength in the fiber direction of the pair of second veneers in frictional contact (static friction) with the first veneer, and stretching of the pair of second veneers in the direction intersecting with the fiber direction thereof can be reduced by the relatively high tensile strength in the fiber direction of the first veneer in frictional contact (static friction) with the pair of second veneers. Thus, cracking attributed to stretching of the first and second veneers in the directions intersecting with the fiber directions of the first and second veneers can be reduced. In regard to the first or second veneer disposed at the bottom and top of the layered-up veneer board in the layering direction, either the front or rear surface is restrained by a pair of platens for compressing the layered-up veneer board, preventing the first or second veneer from stretching in the direction intersecting with the fiber direction thereof.

According to yet another aspect of the veneer dehydration method of the invention, the step (a) forms a layered body by layering a pair of the second veneers on a pair of the first veneers, and forms the layered-up veneer board by layering a plurality of the layered bodies.

According to this aspect, in the relationship between the first and second veneers, the fiber directions of the pair of first veneers and the pair of second veneers intersect with each other. Thus, stretching of the first veneers in the direction intersecting with the fiber direction thereof can be reduced by the relatively high tensile strength in the fiber direction of the pair of second veneers in frictional contact (static friction) with the pair of first veneers, and stretching of the second veneers in the direction intersecting with the fiber direction thereof can be reduced by the relatively high tensile strength in the fiber direction of the pair of first veneers in frictional contact (static friction) with the pair of second veneers. Thus, cracking attributed to stretching of the first and second veneers in the directions intersecting with the fiber directions of the first and second veneers can be reduced. In regard to the first or second veneer disposed at the bottom and top of the layered-up veneer board in the layering direction, either the front or rear surface is restrained by a pair of platens for compressing the layered-up veneer board, preventing the first or second veneer from stretching in the direction intersecting with the fiber direction thereof.

According to yet another aspect of the veneer dehydration method of the invention, the step (a) forms a layered body by layering a set of three of the second veneers on the first veneer, and forms the layered-up veneer board by layering a plurality of the layered bodies.

According to this aspect, in the relationship between the first and second veneers, stretching of the first veneer in the direction intersecting with the fiber direction thereof can be reduced by the relatively high tensile strength in the fiber direction of the pair of second veneers in frictional contact (static friction) with the first veneer, and stretching of the pair of second veneers in the direction intersecting with the fiber direction thereof can be reduced by the relatively high tensile strength in the fiber direction of the first veneer in frictional contact (static friction) with the pair of second veneers. Between the second veneers, i.e., between two second veneers adjacent respectively to the first veneers closest thereto and the second veneer sandwiched between said two second veneers, the effect of reducing stretching of said two second veneers adjacent to the first veneers, in the direction intersecting with the fiber directions of said two second veneers, also acts on the second veneer sandwiched between said two second veneers. Therefore, stretching of the second veneer sandwiched between said two second veneers in the direction intersecting with the fiber direction thereof can be reduced. Thus, cracking attributed to stretching of the first and second veneers in the directions intersecting with the fiber directions of the first and second veneers can be reduced. In regard to the first or second veneer disposed at the bottom and top of the layered-up veneer board in the layering direction, either the front or rear surface is restrained by a pair of platens for compressing the layered-up veneer board, preventing the first or second veneer from stretching in the direction intersecting with the fiber direction thereof.

According to yet another aspect of the veneer dehydration method of the invention, the step (a) forms a layered body by layering a set of three of the second veneers on a pair of the first veneers, and forms the layered-up veneer board by layering a plurality of the layered bodies.

According to this aspect, in the relationship between the first and second veneers, stretching of the first veneer in the direction intersecting with the fiber direction thereof can be reduced by the relatively high tensile strength in the fiber direction of the pair of second veneers in frictional contact (static friction) with the first veneer, and stretching of the pair of second veneers in the direction intersecting with the fiber direction thereof can be reduced by the relatively high tensile strength in the fiber direction of the first veneer in frictional contact (static friction) with the pair of second veneers. Between the second veneers, i.e., between two second veneers adjacent respectively to the first veneers closest thereto and the second veneer sandwiched between said two second veneers, the effect of reducing stretching of said two second veneers adjacent to the first veneers, in the direction intersecting with the fiber directions of said two second veneers, also acts on the second veneer sandwiched between said two second veneers. Therefore, stretching of the second veneer sandwiched between said two second veneers in the direction intersecting with the fiber direction thereof can be reduced. Thus, cracking attributed to stretching of the first and second veneers in the directions intersecting with the fiber directions of the first and second veneers can be reduced. In regard to the first or second veneer disposed at the bottom and top of the layered-up veneer board in the layering direction, either the front or rear surface is restrained by a pair of platens for compressing the layered-up veneer board, preventing the first or second veneer from stretching in the direction intersecting with the fiber direction thereof.

According to yet another aspect of the veneer dehydration method of the invention, the step (a) forms a layered body by layering a set of three of the second veneers on a set of three of the first veneers, and forms the layered-up veneer board by layering a plurality of the layered bodies.

According to this aspect, in the relationship between the first and second veneers, stretching of the first veneer in the direction intersecting with the fiber direction thereof can be reduced by the relatively high tensile strength in the fiber direction of the pair of second veneers in frictional contact (static friction) with the first veneer, and stretching of the pair of second veneers in the direction intersecting with the fiber direction thereof can be reduced by the relatively high tensile strength in the fiber direction of the first veneer in frictional contact (static friction) with the pair of second veneers. Between the first veneers, i.e., between two first veneers adjacent respectively to the second veneers closest thereto and the first veneer sandwiched between said two first veneers, the effect of reducing stretching of said two first veneers adjacent to the second veneers, in the direction intersecting with the fiber directions of said two first veneers, also acts on the first veneer sandwiched between said two first veneers. Therefore, stretching of the first veneer sandwiched between said two first veneers in the direction intersecting with the fiber direction thereof can be reduced. Between the second veneers, i.e., between two second veneers adjacent respectively to the first veneers closest thereto and the second veneer sandwiched between said two second veneers, the effect of reducing stretching of said two second veneers adjacent to the first veneers, in the direction intersecting with the fiber directions of said two second veneers, also acts on the second veneer sandwiched between said two second veneers. Therefore, stretching of the second veneer sandwiched between said two second veneers in the direction intersecting with the fiber direction thereof can be reduced. Thus, cracking attributed to stretching of the first and second veneers in the directions intersecting with the fiber directions of the first and second veneers can be reduced. In regard to the first or second veneer disposed at the bottom and top of the layered-up veneer board in the layering direction, either the front or rear surface is restrained by a pair of platens for compressing the layered-up veneer board, preventing the first or second veneer from stretching in the direction intersecting with the fiber direction thereof.

According to yet another aspect of the veneer dehydration method of the invention, the step (a) includes reversing the first veneer to position the second veneer such that the fiber direction thereof extends along the second direction.

According to this aspect, by simply reversing the first veneer, the second veneer can be positioned such that the fiber direction thereof intersects with the fiber direction of the first veneer.

According to a preferred aspect of the dehydration system of the invention, a veneer dehydration system for removing moisture contained in veneers is constructed. The veneer dehydration system includes a veneer stacking device capable of stacking veneers, layered, a first conveying device for conveying the veneers to the veneer stacking device with a fiber direction of the veneers aligned with a first direction, a second conveying device for conveying the veneers to the veneer stacking device with the fiber direction of the veneers aligned with a second direction intersecting with the first direction, a veneer compression device having first and second platens disposed on either side of a layering direction of the veneers, and a loading device for loading, between the first and second platens, a layered-up veneer board stacked on the veneer stacking device.

According to the invention, cracking attributed to stretching of the first and second veneers in the directions intersecting with the fiber directions of the first and second veneers can effectively be reduced by a very simple configuration of using the anisotropy of the strengths of the veneers. Specifically, the tensile strength of a veneer in the same direction as the fiber direction of the veneer is higher than the tensile strength in the direction intersecting with the fiber direction of the veneer, and therefore the veneer is more likely to stretch and become deformed in the direction intersecting with the fiber direction than in the same direction as the fiber direction. In view of this property inherent in veneers, when compressing the layered-up veneer board having the first and second veneers layered with the fiber directions thereof intersecting with each other, stretching of the first veneer in the direction intersecting with the fiber direction thereof can favorably be reduced by the relatively high tensile strength in the fiber direction of the second veneer in frictional contact (static friction) with the first veneer. Furthermore, stretching of the second veneer in the direction intersecting with the fiber direction thereof can favorably be reduced by the relatively high tensile strength in the fiber direction of the first veneer in frictional contact (static friction) with the second veneer. The invention, therefore, can effectively reduce cracking of the first and second veneers which could be caused as a result of the first and second veneers stretching in the directions intersecting with the fiber directions thereof.

The invention, while simply constructed, is capable of not only restricting a veneer from stretching in a direction intersecting with a fiber direction of the veneer or in a direction in which lathe checks of the veneer expand, but also reducing cracking of the veneer attributed to such stretching.

DETAILED DESCRIPTION

The best modes for carrying out the invention are now described hereinafter with reference to examples.

As shown inFIG. 1, a veneer dehydration system1according to an embodiment of the invention includes a veneer stacking device4capable of stacking veneers2into layers, a conveying device6for conveying veneers2to the veneer stacking device4, a compression device8for compressing the layered veneers2(“layered-up veneer board20,” hereinafter) in a layering direction, a loading device10for loading the layered-up veneer board20of the veneer stacking device4onto the compression device8, an unloading device12for unloading the layered-up veneer board20from the compression device8, and a controller70for controlling the entire system.

A veneer2is obtained by thinly cutting a log using a veneer lathe, not shown. In this embodiment, as shown inFIGS. 2 to 4, the veneer2is in a square shape when viewed from the direction perpendicular to a primary surface of the veneer2(the length of the veneer2along a fiber direction thereof is roughly equal to the length of the veneer2along the direction perpendicular to the fiber direction). Note that, in this embodiment, the veneer2is cut out so that the fiber direction thereof is roughly parallel to one of the two pairs of sides defining the outer periphery of the veneer2.

Also, the concept of the veneer2includes not only a standard-size veneer2that is obtained by cutting a continuous, strip-like veneer with no unnecessary parts into a predetermined standard length as shown inFIG. 2, but also a standard-size veneer2that is obtained by bringing rectangular, narrow veneers2a,2band2ctightly or very closely together, the narrow veneers having most or all of unnecessary parts removed, and then cutting the veneers2a,2band2cinto a predetermined standard length, as shown inFIGS. 3 and 4. The narrow veneers2a,2band2cthat are brought tightly or very closely together are preferably joined using a joining material JM such as a joining tape, an adhesive, of staples, as shown inFIG. 3.

Note that, in order to form such a square veneer2by dividing a rectangular veneer of universal dimensions into two, a conventional method for manufacturing a laminated material, namely a method for manufacturing a laminated veneer material, can be directly used in which a product (a plywood board, a laminated veneer material, etc.) is manufactured by piling multiple veneers2in a staircase pattern with the fiber directions thereof aligned every desired number of veneers, and then gluing them together. Alternatively, after dehydration, two sheets of square veneers2can be connected along the same direction as the fiber direction of these veneers2or along the direction perpendicular to the fiber direction, to once again form a rectangular veneer of universal dimensions, and the abovementioned conventional method for manufacturing a laminated material can be directly used to manufacture a product (a plywood board, a laminated veneer material, etc.).

The term “the same direction as the fiber direction” favorably includes literally the direction same as the fiber direction, as well as the direction roughly extending along the fiber direction. The term “the direction perpendicular to the fiber direction” favorably includes literally the direction orthogonal to the fiber direction, as well as the direction roughly orthogonal to the fiber direction.

As shown inFIG. 5, the veneer stacking device4has a stacking portion4aconfigured to be able to move up and down. The veneers2are piled up on the stacking portion4auntil the height of the piled veneers2reaches a predetermined value. Once the height of the piled veneers2is the predetermined value, the resultant layered-up veneer board20is carried to the loading device10. Note that the height of the layered-up veneer board20is desirably approximately 1 m to 2 m (preferably approximately 1.3 m to 1.7 m) in view of the resiliency of the layered-up veneer board20after compression thereof by the compression device8is finished, and the stability of conveying the layered-up veneer board20by the conveying device6, the loading device10(seeFIG. 1), and the unloading device12(seeFIG. 1).

As shown inFIG. 5, the conveying device6has an upper conveying line62, a lower conveying line64disposed immediately below the upper conveying line62, an inclined conveying portion66, and a needle belt conveyor68. The upper conveying line62is configured as a roller conveyor and is shorter than the lower conveying line64in a conveyance direction. The lower conveying line64is configured as a belt conveyor having a pair of belts64aand64aand has a length reaching the veneer stacking device4. Note that the veneers2having their fiber directions rotated 90 degrees to one another are loaded onto the upper conveying line62and the lower conveying line64.

As shown inFIG. 5, the inclined conveying portion66is disposed at the end of the upper conveying line62. The inclined conveying portion66has an inclined surface tilting downward from the upper conveying line62toward the pair of belts64aand64aof the lower conveying line64, and functions to transfer, to the lower conveying line64, the veneers2conveyed by the upper conveying line62.

The needle belt conveyor68has a pair of belts68aand68ahaving belt-shaped needles and a veneer dropping device68b, and is configured to traverse the veneer stacking device4vertically from a position immediately above the end of the lower conveying line64. It is preferred that the needles of the needle belt conveyor68each have a length equivalent to the thickness of two or more sheets of veneers2.

As shown inFIG. 6, the compression device8includes a lower platen82serving as a base, a vertical machine frame84installed on the side of the lower platen82, a horizontal machine frame85bridging over an upper end of the vertical machine frame84, an activation mechanism86mounted on the horizontal machine frame85, and an upper platen88mounted on the activation mechanism86via a coupling member87. The compression device8is an example of an implementation configuration corresponding to the “veneer compression device” of the invention. The lower platen82is an example of an implementation configuration corresponding to the “first platen” of the invention, and the upper platen88is an example of an implementation configuration corresponding to the “second platen” of the invention.

The lower platen82and the upper platen88are each formed to have an area substantially equal to or slightly larger than the area of each veneer2. As shown inFIG. 6, an in-platen conveyor82ais embedded in the lower platen82. The in-platen conveyor82ais configured to be movable by a lifting device, not shown, between a conveyance position slightly protruding from an upper surface of the lower platen82and a retraction position lower than the upper surface of the lower platen82. Note that the in-platen conveyor82amay be configured to be movable between the conveyance position and the retraction position by means of the elastic force of an elastic body instead of using the lifting device. In such a case, a plurality of lines of grooves can be provided at appropriate intervals in the lower platen82, and the in-platen conveyor82abiased by the elastic body can be positioned in these grooves.

A hydraulic cylinder, for example, can be used as the activation mechanism86. In this case, the upper platen88is attached to a tip of a cylinder rod of the hydraulic cylinder via the coupling member87. Needless to say, the activation mechanism86can be configured to use a screw mechanism, a cam mechanism, or the like. Alternatively, a plurality of the activation mechanisms86can be provided. In such a case, the activation mechanisms86can be controlled individually. Accordingly, when moving the upper platen88up and down, the upper platen88can favorably be prevented from being moved up and down while tilted.

The controller70is configured as a microprocessor such as a CPU, and includes, in addition to the CPU, a ROM for storing processing programs, a RAM for temporarily storing data, input and output ports, and a communication port. A signal and the like from a sensor (not shown) for detecting the height of the piled veneers2are input to the controller70via the input port. The controller70outputs drive signals to the conveying device6, the veneer stacking device4, the compression device8, the loading device10, and the unloading device12via the output port.

Operations of the veneer dehydration system1configured as above are described next. First, the controller70drives the conveying device6and the needle belt conveyor68and, as shown inFIG. 1, conveys to the veneer stacking device4veneers2A and2B that are fed simultaneously and respectively to the upper conveying line62and the lower conveying line64, with the fiber directions of the veneers2A and2B rotated 90 degrees to each other.

The veneer2A conveyed by the upper conveying line62is transferred to the lower conveying line64by the inclined conveying portion66disposed at the end of the upper conveying line62. In so doing, the veneer2A is superposed on the veneer2B conveyed by the lower conveying line64, thereby constructing a layered body2′ having the two veneers2A and2B stacked together, with the fiber directions thereof arranged perpendicular to each other (seeFIG. 8).

The layered body2′ (seeFIG. 8) is conveyed to the needle belt conveyor68by the lower conveying line64. After being conveyed to the needle belt conveyor68, the layered body2′ (seeFIG. 8) is then stuck to the needles of the needle belt conveyor68, conveyed to the position immediately above the stacking portion4aof the veneer stacking device4, pulled away from the needle belt conveyor68by the veneer dropping device68b, and stacked on the stacking portion4a. This operation is repeated by the controller70until the height of the piled veneers2reaches the predetermined value as shown inFIG. 8. This operation eventually forms the layered-up veneer board20in which the veneers2are layered to the predetermined height such that the fiber directions of the respective veneers2are perpendicular to one another.

When layering the veneers2A and2B, a floor plate (portable platen), not shown, is laid on the stacking portion4ain advance, and then the veneers2A and2B are stacked on this floor plate (portable platen), thereby realizing stable positions of the veneers2A and2B when layering the veneers2A and2B and easy shifting of the layered-up veneer board20to the subsequent step. Note that an intermediate floor plate, not shown, may be placed every appropriate number of veneers2A and2B. From the perspective of the effectiveness of dehydration, the sizes of the floor plate (portable platen) and the intermediate floor plate are desirably large enough to cover at least the veneers2A and2B (even if the veneers2A and2B are stacked somewhat irregularly, the sizes of said plates are preferably wide enough so that the veneers2A and2B do not stick out from the floor plate (portable platen)). If necessary, a retaining plate similar to the floor plate may be placed on an upper surface of the layered-up veneer board20as well.

Once the veneers2are layered up to the predetermined height, the controller70drives the veneer stacking device4to carry the layered-up veneer board20to the loading device10and drives the loading device10and the in-platen conveyor82a(including the unshown lifting device) to carry the layered-up veneer board20to the compression device8. Specifically, the in-platen conveyor82ais driven to be moved by the unshown lifting device to the conveyance position slightly protruding from the upper surface of the lower platen82, and is driven such that the layered-up veneer board20is transferred from the loading device10to a predetermined position of the lower platen82.

Once the layered-up veneer board20is carried to the predetermined position of the lower platen82of the compression device8, the controller70drives the unshown lifting device such that the in-platen conveyor82amoves to the retraction position lower than the upper surface of the lower platen82, and drives the activation mechanism86to bring the upper platen88close to the lower platen82, as shown inFIG. 7.

Consequently, the layered-up veneer board20is compressed between the upper platen88and the lower platen82in the layering direction, thereby removing moisture contained in each veneer2. Wood such as the veneers2is an anisotropic material in which the tensile strength in the same direction as the fiber direction of said material is higher than the tensile strength in the direction perpendicular to the fiber direction. Therefore, when compressing the layered-up veneer board20in the layering direction, the layered-up veneer board20having the veneers2layered such that the fiber directions of the respective veneers2are perpendicular to one another, stretching of the veneer2A in the direction intersecting with the fiber direction thereof can favorably be reduced by the relatively high tensile strength in the fiber direction of the veneer2B which is in frictional contact (static friction) with the veneer2A, and stretching of the veneer2B in the direction intersecting with the fiber direction thereof can favorably be reduced by the relatively high tensile strength in the fiber direction of the veneer2A which is in frictional contact (static friction) with the veneer2B.

In the present embodiment, the abovementioned effect of inhibiting elongational deformation acts on both the front and rear surfaces of all the veneers2other than the top and bottom veneers2out of the veneers2constituting the layered-up veneer board20so that adjacent veneers2inhibit each other from stretching and becoming deformed in the direction perpendicular to their fiber direction. Therefore, elongational deformation in the directions perpendicular to the fiber directions can effectively be reduced. As to the top and bottom veneers2out of the veneers2constituting the layered-up veneer board20, the abovementioned effect of inhibiting elongational deformation acts on either the front surfaces or the rear surfaces to reduce elongational deformation of these top and bottom veneers2in the directions perpendicular to the fiber directions, but elongational deformation of the other surfaces in the directions perpendicular to the fiber directions is reduced by the frictional force between the veneer2and the upper platen88or the lower platen82.

According to the veneer dehydration system1of the foregoing embodiment of the invention, in spite of such an extremely simple configuration in which the veneers2are layered such that the fiber directions of the respective veneers2are perpendicular to one another, elongational deformation of each of the veneers2of the layered-up veneer board20in the direction perpendicular to its fiber direction can be reduced, thereby effectively reducing cracking of the veneers2attributed to such elongational deformation.

Furthermore, according to the veneer dehydration system1of the foregoing embodiment of the invention, even if the shapes of the veneers2such as the lengths of the respective sides of each veneer2and the angles of cut of the respective sides are somewhat non-uniform, or even if the veneers2are layered slightly off, the veneers2adjacent to each other prevent each other from stretching and becoming deformed in the directions perpendicular to their fiber directions. Therefore, the formation of cracks in each veneer2attributed to elongational deformation thereof can favorably be reduced. Since the shape accuracy of the veneers2and the accuracy of layering the veneers2do not need to be exceptionally precise, the veneer dehydration system1of the present invention is excellent in practicality. Even if the outer peripheries of some of the veneers2do not overlap properly with each other and therefore cannot be dehydrated adequately by the compression device8due to poor shapes or poor layering of such veneers2, since the outer peripheries of the veneers2tend to k more easily than the other parts of the veneers2, the veneers2can be dehydrated adequately in the subsequent heat-king step. For this reason, poor shapes and poor layering of the veneers2are practically not obstacles.

Although, in the present embodiment, the veneers2are layered such that the fiber directions of the respective veneers2are perpendicular to one another, how the fiber directions are arranged is not limited to such perpendicular arrangement so long as the fiber directions of the respective veneers2intersect with one another. When cutting a log with a veneer lathe to obtain the veneers2, it is rare for the direction of the edge of the knife cutting the log to be parallel to the fiber direction of the log. Specifically, in most cases, as shown in a veneer102of a modification inFIG. 9, the fiber direction of a veneer such as the veneer102forms an angle with each of the sides of the veneer102defining the outer periphery of the veneer102.

In order to form a layered-up veneer board120using veneers102, the veneers102can be layered, with the front and rear sides of the respective veneers102reversed, so that the fiber directions of the respective veneers102intersect with one another, as shown inFIG. 10. In so doing, in place of the conveying device6described above, a conveying device106of a modification shown inFIG. 11may be used.

As shown inFIG. 11, the conveying device106has an upper conveying line162, a lower conveying line164disposed immediately below the upper conveying line162, a reversing mechanism166, and a needle belt conveyor68. The upper conveying line162is configured as a belt conveyor having a pair of belts162aand162aand is long enough to cross the veneer stacking device4. The upper conveying line162and the lower conveying line164are, respectively, examples of implementation configurations corresponding to the “first conveying device” and the “second conveying device” of the invention.

As shown inFIG. 11, the lower conveying line164is configured as a belt conveyor having a pair of belts164aand164aand is shorter than the upper conveying line162in the conveyance direction. Specifically, the lower conveying line164has a length reaching a part immediately before the veneer stacking device4. The veneers102having their fiber directions arranged in the same direction are loaded onto the upper conveying line162and the lower conveying line164.

As shown inFIG. 11, the reversing mechanism166is disposed at the end of the upper conveying line162to reverse each of the veneers102carried by the upper conveying line162, and transfer each of the veneers102to the veneer stacking device4.

It is preferred that the needles of the needle belt conveyor68each have a length equivalent to the thickness of two or more sheets of veneers102.

Using the conveying device106configured as above, the veneers102are layered such that the fiber directions of the respective veneers102intersect with one another to form a layered body102′ as shown inFIG. 10. Then, a layered-up veneer board120having a predetermined height is formed by layering such layered bodies102′ up to the predetermined height. Note that the veneer stacking device4is configured to be able to convey the layered-up veneer board120to the loading device10.

According to the present embodiment and the foregoing modifications, the layered-up veneer board20is formed by layering the veneers2such that the fiber directions of the respective veneers2are perpendicular to one another; however, other configurations are possible. For example, as shown in a modification inFIG. 12, a layered body202′ may be formed by layering a pair of veneers202B and202B on one veneer202A having the fiber direction thereof extending in a predetermined direction, such that the fiber direction of the pair of veneers202B and202B intersects with (is perpendicular to) the fiber direction of the veneer202A, and then the layered body202′ may repeatedly be layered up to a predetermined height, to form a layered-up veneer board220. In other words, the layered-up veneer board220is formed by repeatedly and alternately layering the single veneer202A and the pair of veneers202B and202B in the layering direction, with the fiber direction of the pair of veneers202B and202B intersecting with (perpendicular to) the fiber direction of the veneer202A.

As shown in a modification inFIG. 13, a layered body302′ may be formed by layering a pair of veneers302B and302B on a pair of veneers302A and302A having the fiber direction thereof extending in a predetermined direction, such that the fiber direction of the pair of veneers302B and302B intersects with (is perpendicular to) the fiber direction of the pair of veneers302A and302A, and then the layered body302′ may repeatedly be layered up to a predetermined height, to form a layered-up veneer board320. In other words, the layered-up veneer board320is formed by layering the veneers302A and302B such that the fiber directions of the respective veneers intersect with each other (are perpendicular to each other) every two layers. More specifically, the layered-up veneer board320is formed by repeatedly and alternately layering the pair of veneers302A and302A and the pair of veneers302B and302B in the layering direction, the fiber direction of the pair of veneers302B and302B intersecting with (being perpendicular to) the fiber direction of the pair of veneers302A and302A.

Further, as shown in a modification inFIG. 14, a layered body402′ may be formed by layering three veneers402B,402B and402B on one veneer402A having the fiber direction thereof extending in a predetermined direction, such that the fiber direction of the set of veneers402B,402B and402B intersects with (is perpendicular to) the fiber direction of the veneer402A, and then the layered body402′ may repeatedly be layered up to a predetermined height, to form a layered-up veneer board420. In other words, the layered-up veneer board420is formed by repeatedly and alternately layering the single veneer402A and the set of three veneers402B,402B and402B in the layering direction, with the fiber direction of the set of veneers402B,402B and402B intersecting with (perpendicular to) the fiber direction of the veneer402A.

As shown in a modification inFIG. 15, a layered body502′ may be formed by layering a set of three veneers502B,502B and502B on a pair of veneers502A and502A having the fiber direction thereof extending in a predetermined direction, such that the fiber direction of the set of three veneers502B,502B and502B intersects with (is perpendicular to) the fiber direction of the pair of veneers502A and502A, and then the layered body502′ may repeatedly be layered up to a predetermined height, to form a layered-up veneer board520. In other words, the layered-up veneer board520is formed by repeatedly and alternately layering the pair of veneers502A and502A and the set of three veneers502B,502B and502B in the layering direction, with the fiber direction of the set of veneers502B,502B and502B intersecting with (perpendicular to) the fiber direction of the pair of veneers502A and502A.

Alternatively, as shown in a modification inFIG. 16, a layered body602′ may be formed by layering a set of three veneers602B,602B and602B on a set of three veneers602A,602A and602A having the fiber direction thereof extending in a predetermined direction, such that the fiber direction of the set of three veneers602B,602B and602B intersects with (is perpendicular to) the fiber direction of the set of three veneers602A,602A and602A, and then the layered body602′ may repeatedly be layered up to a predetermined height, to form a layered-up veneer board620. In other words, the layered-up veneer board620is formed by layering the veneers602A and602B such that the fiber directions of the respective veneers602A and602B intersect with each other (are perpendicular to each other) every three layers. More specifically, the layered-up veneer board620is formed by repeatedly and alternately layering the set of three veneers602A,602A and602A and the set of three veneers602B,602B and602B in the layering direction, with the fiber direction of the set of three veneers602B,602B and602bintersecting with (perpendicular to) the fiber direction of the set of three veneers602A,602A and602A.

As to all the veneers202A,202B,302A,302B other than the top and bottom veneers202A,202B,302A, and302B out of the veneers202A,202B,302A, and302B constituting the layered-up veneer boards220and320of the modifications shown inFIGS. 12 and 13, the veneers202B,202A,302B, and302A with the intersecting (perpendicular) fiber directions are disposed adjacent to either the front surfaces or the rear surfaces of said veneers other than the top and bottom veneers. For this reason, although the veneers202A,202B,302A,302B stretch and become deformed in the directions perpendicular to the respective fiber directions, when compressing the layered-up veneer boards220and320in the layering direction, stretching of the veneers202A,302A in the directions intersecting with the fiber directions thereof is favorably reduced by the relatively high tensile strengths in the fiber direction of the veneers202B,302B in frictional contact (static friction) with the veneers202A,302A. At the same time, stretching of the veneers202B,302B in the directions intersecting with the fiber directions thereof is favorably reduced by the relatively high tensile strength in the fiber directions of the veneers202A,302A in frictional contact (static friction) with the veneers202B,302B.

As to the top and bottom veneers202A,202B,302A,302B of the veneers202A,202B,302A, and302B constituting the layered-up veneer boards220and320, elongational deformation of either the front surfaces or the rear surfaces of said top and bottom veneers in the directions perpendicular to the respective fiber directions thereof is reduced by the frictional force between the upper platen88or the lower platen82and said front or rear surfaces.

In the layered-up veneer boards420,520, and620of the modifications shown inFIGS. 14, 15 and 16, between the veneers402A,502A,602A and the veneers402B,502B,602B disposed on either the front surfaces or the rear surfaces of the veneers402A,502A,602A such that the fiber directions of the veneers402B,502B,602B intersect with (are perpendicular to) the fiber directions of the veneers402A,502A,602A, stretching of the veneers402A,502A,602A in the directions intersecting with the fiber directions thereof is favorably reduced by the relatively high tensile strength in the fiber directions of the veneers402B,502B,602B in frictional contact (static friction) with the veneers402A,502A,602A. At the same time, stretching of the veneers402B,502B,602B in the directions intersecting with the fiber directions thereof is favorably reduced by the relatively high tensile strength in the fiber directions of the veneers402A,502A,602A in frictional contact (static friction) with the veneers402B,502B,602B. Between the veneers402B,502B,602B, i.e., between two veneers402B,502B,602B adjacent respectively to the veneer402A,502A,602A closest thereto and the veneer402B,502B,602B disposed between said two veneers402B,502B,602B, the aforementioned effect of reducing elongational deformation that acts between the veneers402A,502A,602A and said two veneers402B,502B,602B adjacent respectively to the veneers402A,502A,602A also acts on the veneer402B,502B,602B disposed between said two veneers402B,502B,602B, thereby reducing elongational deformation of the veneer402B,502B,602B between said two veneers402B,502B,602B in the direction intersecting with (perpendicular to) the fiber directions thereof. Note that elongational deformation of either the front surfaces or the rear surfaces of the top and bottom veneers402A,402B,502A,502B,602A,602B in the directions perpendicular to the fiber directions thereof is reduced by the frictional force between the upper platen88or the lower platen82and said front or rear surfaces.

Thus, even when stress is applied to the veneers402A,402B,502A,502B,602A,602B and causes elongational deformation of these veneers in the directions perpendicular to the fiber directions thereof as a result of compressing the layered-up veneer boards420,520,620of the modifications in the layering direction, elongational deformation of the veneers402A,402B,502A,502B,602A,602B in the directions intersecting with (perpendicular to) the fiber directions thereof can favorably be reduced. The practical number of veneers to be stacked with the fiber directions thereof aligned in the same direction, is preferably determined on the basis of an experiment in line with the thickness of each veneer, the condition of the front surface of each veneer (cracking or separation of wood fibers upon cutting with a veneer lathe), and other substances (conditions) of each veneer.

The layered-up veneer boards220,320,420,520,620of the modifications can be formed using the conveying device6and the veneer stacking device4shown inFIG. 5. Specifically, in order to form the layered-up veneer board220, the pair of layered-up veneer boards202B and202B may be fed to the upper conveying line62and the single veneer202A having the fiber direction thereof intersecting with (perpendicular to) the fiber direction of the pair of veneers202B and202B may be fed to the lower conveying line64. In order to form the layered-up veneer board320, the pair of layered-up veneer boards302B and302B may be fed to the upper conveying line62and the pair of veneers302A and302A having the fiber direction thereof intersecting with (perpendicular to) the fiber direction of the pair of veneers302B and302B may be fed to the lower conveying line64.

Also, in order to form the layered-up veneer board420, the set of three layered-up veneer boards402B,402B and402B may be fed to the upper conveying line62, and the single veneer402A having the fiber direction thereof intersecting with (perpendicular to) the fiber direction of the set of three veneers402B,402B and402B may be fed to the lower conveying line64. Further, in order to form the layered-up veneer board520, the set of three layered-up veneer boards502B,502B and502B may be fed to the upper conveying line62, and the pair of veneers502A and502A having the fiber direction thereof intersecting with (perpendicular to) the fiber direction of the set of three veneers502B,502B and502B may be fed to the lower conveying line64. In order to form the layered-up veneer board620, the set of three layered-up veneer boards602B,602B and602B may be fed to the upper conveying line62, and the set of three veneers602A,602A and602A having the fiber direction thereof intersecting with (perpendicular to) the fiber direction of the set of three veneers602B,602B and602B may be fed to the lower conveying line64.

According to the present embodiment and the foregoing modifications, the standard-size veneers2,102,202A,202B,302A,302B,402A,402B,502A,502B,602A,602B, which are each in a square shape when viewed from the direction perpendicular to the primary surfaces of said veneers, are formed by cutting a continuous, strip-like veneer with no unnecessary parts into a predetermined standard length or by bringing the rectangular narrow veneers2a,2b, and2ctightly or very closely together, the narrow veneers having most or all of unnecessary parts removed, and then cutting the veneers2a,2band2cinto a predetermined standard length; however, other configurations are possible. For example, a veneer702of a modification shown inFIG. 17, which is in a square shape when viewed from the direction perpendicular to the primary surface of said veneer, may be formed by bringing tightly or very closely together rectangular veneers702aand702beach having the long side approximately twice as long as the short side when viewed from the direction perpendicular to the primary surface thereof, with the fiber directions thereof aligned. The veneers702aand702bcan be joined using a joining material such as a joining tape, an adhesive, or staples.

In order to remove moisture contained in the veneer702, a desired number of (including one) veneers702, layered, are loaded onto the upper conveying line62of the conveying device6, and then a desired number of (including one) veneers702, layered, are loaded onto the lower conveying line64, with the fiber direction thereof intersecting with (perpendicular to) the fiber direction of the veneers702loaded onto the upper conveying line62, thereby obtaining a layered-up veneer board720(seeFIG. 17) in which the fiber directions of the veneers702intersect with (are perpendicular to) each other every desired number of veneers, and then the layered-up veneer board720is compressed by the compression device8.

The present embodiment and the foregoing modifications use the standard-size veneers2,102,202A,202B,302A,302B,402A,402B,502A,502B,602A,602B, which are each in a square shape when viewed from the direction perpendicular to the primary surfaces thereof; however, other configurations are possible. For example, as shown inFIGS. 18 and 19, standard-size veneers802A and802B that are each in a rectangular shape when viewed from the direction perpendicular to the primary surfaces thereof may be used. As shown inFIG. 18, the standard-size veneer802A is formed such that the fiber direction thereof is roughly the same as the extending direction of the long side of the veneer802A, whereas, as shown inFIG. 19, the standard-size veneer802B is formed such that the fiber direction thereof is roughly the same as the extending direction of the short side of the veneer802B.

Also, as shown inFIGS. 20 and 21, the standard-size veneers802A and802B may be formed by bringing rectangular, narrow veneers802Aa,802Ab and802Ac and narrow veneers802Ba,802Bb and802Bc tightly or very closely together, the narrow veneers having most or all of unnecessary parts removed, and then cutting the narrow veneers802Aa,802Ab and802Ac and the narrow veneers802Ba,802Bb and802Bc into a predetermined standard length. The narrow veneers802Aa,802Ab and802Ac and the narrow veneers802Ba,80Bb and802bcthat are brought tightly or very closely together are preferably joined using the joining material JM such as a joining tape, an adhesive, or staples (seeFIG. 20).

As shown inFIG. 23, the standard-size veneers802A and802B may be formed by bringing tightly or very closely together two square veneers with the fiber directions thereof aligned, the square veneers each having the long and short sides roughly equal in length to each other when viewed from the direction perpendicular to the primary surface thereof. The two square veneers can be joined using a joining material such as a joining tape, an adhesive, or staples.

In order to remove moisture contained in the standard-size veneers802A and802B configured as above, a desired number of standard-size veneers802A and a desired number of standard-size veneers802B may be layered alternately to form a layered-up veneer board820as shown inFIG. 22, and then the resultant layered-up veneer board820may be compressed by the compression device8.

Note that, in a case where the standard-size veneers802A and802B are each a rectangular veneer of universal dimensions, a conventional method for manufacturing a laminated material, namely a method for manufacturing a laminated veneer material, can be directly used in which a product (a plywood board, a laminated veneer material, etc.) is manufactured by piling multiple standard-size veneers802A and802B in a staircase pattern, with the fiber directions thereof aligned every desired number of veneers, and then gluing them together.

According to the present embodiment and the foregoing modifications, the lengths of the sides of each of the veneers2,102,202A,202B,302A,302B,402A,402B,502A,502B,602A,602B,702a,702b,802A, and802B are universal; however, the lengths of the sides may be any length.

According to the present embodiment and the foregoing modification, the single layered-up veneer board20,120,220,320,420,520,620,720is compressed by the compression device8; however, other configurations are possible. Specifically, a plurality of the layered-up veneer boards20,120,220,320,420,520,620,720may be compressed by the compression device8. In this case, the lower platen82and the upper platen88may each be formed to have an area roughly equal to or slightly larger than the areas of the veneers2,102,202A,202B,302A,302B,402A,402B,502A,502B,602A,602B,702,802A, and802B. In such a case, it is preferred that a plurality of the activation mechanisms86be provided.

According to the present embodiment and the foregoing modifications, the veneers2A,102,202A,302A,402A,502A,602A,702, and802A and the veneers2B,102,202B,302B,402B,502B,602B,702, and802B are layered such that the fiber directions on the primary surfaces thereof are perpendicular to one another; however, other configurations are possible. For example, as shown in a layered-up veneer board920of a modification inFIG. 24, a veneer902A and a veneer902B may be layered in such a manner that the extending direction of lathe checks903A (cracking caused due to the difference in dimensions between the inner and outer peripheries of a veneer when a rotary lathe thinly cuts a log into a veneer and deforms the resultant veneer into a flat shape) formed in the veneer902A and the extending direction of lathe checks903B (cracking caused due to the difference in dimensions between the inner and outer peripheries of a veneer when a rotary lathe thinly cuts a log into a veneer and deforms the resultant veneer into a flat shape) formed in the veneer902B are perpendicular to the fiber direction of the veneer902B and the fiber direction of the veneer902A, respectively.

According to this configuration, when compressing the layered-up veneer board920, elongational deformation of the veneers902A in a direction in which the lathe checks903A expand (the direction intersecting with the fiber direction of the veneers902A) can favorably be reduced by the relatively high tensile strength in the fiber direction of the veneers902B in frictional contact (static friction) with the veneers902A, and elongational deformation of the veneers902B in a direction in which the lathe checks903B expand (the direction intersecting with the fiber direction of the veneers902B) can favorably be reduced by the relatively high tensile strength in the fiber direction of the veneers902A in frictional contact (static friction) with the veneers902B.

Accordingly, even when the veneers902A and902B are made thicker (e.g., 6.0 mm or more) than the conventional veneers (2.0 mm to 4.0 mm), cracking of the veneers902A and902B that is attributed to elongational deformation of the veneers902A and902B in the directions in which the lathe checks903A and903B expand, can favorably be reduced. Specifically, further development of the lathe checks903A and903B which expand proportionally to the increase in the thicknesses of the veneers902A and902B can favorably be reduced. This modification may be consistent with the recent technological trends of increasing the thicknesses of veneers as one of the purposes of reducing the amounts of adhesives used in manufacturing plywood boards.

The present embodiment illustrates an example of the modes for carrying out the invention. Thus, the invention is not limited to the configuration of the present embodiment. The correspondence relationship between the respective components of the present embodiment and the respective components of the invention are described below.

REFERENCE SIGNS LIST