JP2009299383A - Round bar - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a round bar which is high in strength against a bending load and small in deflection. <P>SOLUTION: The round bar A is formed by cutting a peripheral surface into a round bar, and made of laminated wood B obtained by alternately laminating veneers 1 different in density on each other. Since the laminated wood B obtained by alternately laminating the veneers 1 different in density on each other, is employed, the round bar can reduce the deflection by increasing the rigidity thereof by the veneers 1a high in density, and can improve the strength by enhancing the flexibility and stiffness by the veneers 1b low in density. Thus the round bar A high in strength against application of a bending load and small in deflection, can be obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a round bar used as a construction building member such as a handrail.

  In the construction building member, for example, a handrail attached to a corridor or a staircase in a house is used for walking assistance, and thus it is necessary to ensure safety against external force. For this reason, the mechanical characteristics required as a handrail are defined in the Better Living Standard (BL Standard). In this BL standard, handrails are attached with mounting hardware at a predetermined interval to a gypsum board equivalent to a wall, a simulated housing made of concrete, etc., and the center between the mounting hardware is used as a force point until a predetermined maximum load is reached. Mechanical characteristics are evaluated by applying pressure in the vertical direction and measuring the amount of handrail deflection at the applied point.

  And in handrails, it is necessary to support the weight of the pedestrian, so when the bending load is applied, the strength to crack and break is high, and when the pedestrian puts weight on the handrail, In order to give a sense of anxiety when bent, it is particularly necessary that the amount of deflection when a bending load is applied is small.

  As described above, the round bar used for the handrail is required to have mechanical properties such as high strength when bending load is applied and low deflection. Here, in order to reduce the deflection, it is necessary to use a material having high rigidity. However, since a material having high rigidity is brittle, the bending strength is generally low. On the other hand, a material with high flexibility is sticky and does not easily crack or break even when a large load is applied, so that the bending strength is generally high, but a large amount of deflection occurs. Thus, a round bar used for a handrail is required to have the contradictory properties of rigidity and flexibility.

  And in homes, especially wooden homes, handrails are often made of wooden materials, but it is difficult to obtain such mechanical characteristics with solid wood, so as a material for making handrails, In many cases, a laminated material made of a material having a high density such as oak, elm, rubber, rice pine, etc., or a wood laminate material such as LVL is used (see, for example, Patent Documents 1 and 2).

For example, a round bar made of a single wood made from a small piece of wood with a small cross-section is made into a round bar by cutting the outer circumference into a circular or elliptical shape. Used as a slide.
JP 2003-293542 A JP 2006-152535 A

  However, it is difficult to sufficiently satisfy the mechanical properties that the strength is high when bending load is applied and the deflection is small even in the round bar manufactured using the wood laminate material in this way. is there.

  On the other hand, wood such as oak, elm, rubber, rice pine, etc., and tree species such as tammo and cruin are used as wood for producing wood laminates, but there is a problem of high costs due to depletion of natural resources. In particular, there is a problem that logging of timber becomes an environmental burden, such as abnormal weather caused by destruction of natural forests such as tropical forests.

  The present invention has been made in view of the above points, and has an object to provide a round bar having high strength against bending load and low deflection, and is low in cost and low in environmental load. Is intended to provide.

  The round bar according to the present invention is formed of a wood laminate in which single plates having different densities are alternately laminated, and the outer periphery is cut into a round bar shape.

  According to the present invention, the use of the wood laminated material in which the single plates having different densities are alternately laminated, the rigidity and rigidity are reduced by the high-density single plate to reduce the deflection, while the low-density single plate provides flexibility and stickiness. It is possible to increase the bending strength and to obtain a round bar having high strength and low deflection when a bending load is applied.

  In the present invention, the wood laminate is formed by using a single plate having a low density that is thicker than a single plate having a high density.

  According to the present invention, when producing a wood laminated material in which single plates are laminated, the low density single plate is compressed and thinned so that the thickness and density are the same as the high density single plate. And variation in mechanical characteristics can be reduced.

  Further, the present invention is characterized in that a material made of eucalyptus material is used as a single plate having a high density and a material made of poplar material is used as a single plate having a low density.

  Eucalyptus and poplar are mainly produced in regenerated forests called afforested trees, and can be obtained stably at low cost without destroying natural forests. A rod can be produced.

  According to the present invention, the use of the wood laminated material in which the single plates having different densities are alternately laminated, the rigidity and rigidity are reduced by the high density single plate to reduce the deflection, while the low density single plate provides flexibility and stickiness. It is possible to increase the bending strength and to obtain a round bar having a high bending strength and a small deflection.

  Further, by using eucalyptus as a single plate having a high density and poplar as a single plate having a low density, a round bar can be manufactured at a low cost and with a small environmental load.

  Hereinafter, the best mode for carrying out the present invention will be described.

  The round bar A according to the present invention is manufactured by cutting a wood laminate B. First, the production of the wood laminate B will be described.

  FIG. 2 shows an example of the manufacturing process of the round bar A. A single plate laminating step S1 in which the single plates 1 are laminated to produce the single plate laminated material 2, and the single plate laminated material 2 is cut into pieces. The splitting process S2, the fork processing step S3 for jointing the edge 4 of the edge of the split material 3 cut, the joining step S4 for connecting the edges 4 of the split material 3 to each other, and connecting the slit 3 A long laminating step S5 for laminating the long material 5 obtained in this way to produce a long laminated material 6, and the long laminated material 6 is cut along the longitudinal direction and divided so that the cross section becomes substantially square. The wood laminate B can be obtained through the dividing step S6.

  The single plate laminating step S1 is a step of producing the single plate laminated material 2 by laminating the single plates 1 as described above. As the single plate 1, a thin plate material obtained by thinly slicing wood is used. In the present invention, a plurality of types of single plates 1 obtained from wood having different densities are used as the single plate 1, and a plurality of types of single plates 1 having different densities are alternately stacked.

  For example, when two types of single plates 1a and 1b having different densities are used, the single plate 1a having a high density and the single plate 1b having a low density are alternately stacked. Moreover, when using two kinds of single plates 1a and 1b, such as a single plate 1a having a high density and a single plate 1b having a low density, the single plate 1a having a high density is made of wood having an absolute dry specific gravity of 0.6 or more. Preferably, the low density single plate 1b is made of wood having an absolute dry specific gravity of 0.5 or less.

  Examples of wood tree species having an absolute dry specific gravity of 0.6 or more include eucalyptus, rubber, cruin, capol, and kempas. Examples of wood tree species having an absolute dry specific gravity of 0.5 or less include poplar, falkata, kiri, acacia, and radiata pine. As the single plate 1a having a high density and the single plate 1b having a low density, any single plate selected from these tree species can be used.

  Here, high-density wood generally has high rigidity and is difficult to be deformed, so that the bending when a bending load is applied is small, but the bending strength until breaking is low because of the brittleness. In addition, low density wood is generally flexible and sticky and has a high bending strength until it breaks when a bending load is applied, but it is easily deformed, so a large amount of deflection occurs when a bending load is applied. To do. In this way, high density wood has rigidity and low wood has flexibility, so by alternately laminating high density wood veneers 1a and low density wood veneers 1b, It is possible to obtain a laminated material having a small deflection and a high strength against a bending load.

  As the single plate 1a having a high density and the single plate 1b having a low density, various kinds of wood as described above can be used, and are not particularly limited. Among these, as the single plate 1a having a high density, It is particularly preferable to use a single plate of eucalyptus and a single plate of poplar as the low-density single plate 1b. Eucalyptus has an absolute dry specific gravity of about 0.7 and is a hard material with short fibers. For this reason, it is highly rigid and difficult to be deformed, and the amount of bending with respect to the bending load is small, but on the other hand, it is a brittle material with low stickiness and relatively low bending strength until failure. On the other hand, poplar has an absolute dry specific gravity of about 0.45 and is a flexible material having a long fiber length. For this reason, there exists a soft stickiness and it can obtain the bending strength until it leads to destruction, but the deflection amount with respect to a bending load is large. For this reason, eucalyptus and poplar alone are not suitable as a material for the round bar A used for handrails, etc., but by using eucalyptus single plate 1a and poplar single plate 1b alternately stacked, The performances of poplars are complemented with each other, and a laminated material having a small deflection and a high strength against a bending load can be obtained.

  Moreover, eucalyptus and poplar are mainly produced in regenerated forests called planted trees. For this reason, eucalyptus and poplar can be obtained without destroying natural forests and causing abnormal weather, etc. Also, since they are produced while being regenerated as regenerated forests, they can be stably produced at low cost. It can be obtained. Therefore, eucalyptus and poplar can be stably obtained at low cost with a low environmental load. By using eucalyptus as the high density single plate 1a and poplar as the low density single plate 1b, the cost can be reduced. In addition, the round bar A can be produced with a small environmental load.

In producing the single plate laminate 2 in the single plate lamination step S1 using the single plates 1 having different densities as described above, first, each single plate 1 is inspected, and then each single plate 1 is pressed with a hot platen. Then heat and pressurize. The hot platen temperature is set to about 180 ° C., and the pressure is set to about 1 MPa (about 10 kgf / cm ² ). By heating and pressurizing the veneer 1 in this way, the moisture content in the veneer 1 In order to prevent warpage during storage. Next, after applying an adhesive to each single plate 1, the single plates 1a and 1b having different densities are alternately stacked. The adhesive is not particularly limited, and for example, a melamine urea adhesive, a phenol adhesive, or an adhesive in which both are mixed can be used. Thus, after laminating | stacking the single plate 1 which apply | coated the adhesive agent, the single plate laminated material 2 which laminated | stacked each single plate 1 can be produced by performing a press and heating and pressurizing. The hot platen temperature at this time is set to about 110 ° C., and the pressure is set to about 1.1 MPa (about 11 kgf / cm ² ). In laminating the veneer 1, there are a method of laminating so that the fiber directions of the veneers 1 are alternately orthogonal, and a method of laminating the fiber directions of the veneer uniformly, and any of the present invention However, in the round bar A used as a long member such as a handrail, it is preferable to stack the single plate 1 with the fiber direction kept constant in order to obtain high bending strength.

  Here, when the rectangular single-plate laminated material 2 is produced using, for example, a square plate as the single plate 1, it is necessary to simultaneously connect in the lateral direction (plane direction) when the single plates 1 are stacked up and down. There is. At this time, as shown in FIG. 3 (a), the single plates 1 are stacked one above the other while gradually increasing the size of the horizontal displacement, and the ends of the single plates 1 that are connected horizontally are superposed and pressed in this state. Lamination is performed by molding, heating and pressing. In this case, the inclined portions 10 are generated at both ends corresponding to the displacement of the single plate 1, and therefore, by removing the inclined portions 10 by cutting the broken line portions in FIG. A rectangular plate-like single plate laminate 2 as shown in FIG.

This single-plate laminated material 2 is stacked and cured for about one week, and then the surface and the back surface are polished with a horizontal belt sander or the like to perform a sanding process for roughing the surface, and further finished to a predetermined dimension. For example, when a single plate 1 having a square L ₁ (= 840 mm) is used, L ₂ (= 205 mm) between the lower single plate 1 and the upper single plate 1 as shown in FIG. As shown in FIG. 3B, by laminating the single plate 1 up and down while shifting the plate 1 horizontally so as to be displaced, performing laminating press, cutting and removing the inclined portion 10, and finishing to a predetermined dimension. A single plate laminate 2 of L ₁ (= 840 mm) × L ₃ (= 1250 mm) × thickness D ₁ (= 20 mm) can be obtained.

  Here, as described above, when the single plate 1 having different densities is laminated to produce the single plate laminated material 2, the thin single plate 1a having a high density is replaced with the thick single plate 1b having a low density. It is preferable to use one. Then, as shown in FIG. 4 (a), a single plate 1a having a high density and a thin thickness and a single plate 1b having a low density and a high thickness are alternately stacked, and pressure P is applied thereto, as shown in FIG. 4 (b). When the lamination pressing is performed, the single plate 1b having a low density has a soft structure, so that the single plate 1b is compressed so that the thickness is reduced by pressurization, the density is increased, and the bending strength is improved. For example, it is said that when the thickness is compressed to about 2/3, the Young's modulus is improved by about 25%.

  In this way, the single plate 1b having a low density is compressed by the pressing pressure when the single plate laminated material 2 is manufactured, and the density can be brought close to the single plate 1a having a high density. The thickness after compression can be made close to the thickness of the single plate 1a having a high density, and the single plate 1a, 1b having a different density is combined. The variation in target characteristics can be reduced. Further, as shown in FIG. 4B, the high density single plate 1a has a dense and hard fiber structure, whereas the low density single plate 1b has a loose and soft fiber structure. The fiber structure of the high-density single plate 1a bites into the surface layer of the low single plate 1b, and the high-density single plate 1a and the low-density single plate 1b can be surface-bonded with high adhesion. It is possible to reduce abale and krui in the state.

  When the thin single plate 1a having a high density is used and the thick single plate 1b having a low thickness is used, the ratio of the thicknesses of the single plates 1a and 1b is that of the single plate 1a having a high density. When the thickness is 100, it is preferable to set the thickness of the low density single plate 1b to be in the range of 105 to 115, and the high density single plate 1a has a thickness of about 1.4 to 1.8 mm. The single plate 1b having a low density is preferably set to a thickness of about 1.6 to 2.0 mm.

  The single plate laminate 2 produced as described above is insufficient in thickness and length to be processed into a round bar A such as a handrail. For this reason, a woody laminated material B having a size suitable for processing the round bar A is produced from the single plate laminated material 2.

That is, first, the single-plate laminated material 2 is cut into pieces in the cutting step S2. In this split cutting, the single-plate laminated material 2 formed in a rectangular plate shape as described above is cut with a cutter 11 or the like along the longitudinal direction, and a small rectangular plate-shaped member as shown in FIG. This is done by producing the split material 3. In the embodiment of FIG. 5 (a), L ₁ (= 840 mm) × L ₃ (= 1250 mm) single-plate laminated material 2 is cut into seven equal parts, and a split material having a width L ₄ (= 120 mm). 3 is produced.

  Next, in the fore edge processing step S3, the fore edge 4 of the end portion of the undercut material 3 that has been cut into pieces as described above is joint processed. In the embodiment of FIG. 5B, the fore edge 4 is processed into the finger joint 12, but the type of joint such as a scuff joint is arbitrary. Further, as shown in FIG. 5B, the finger joint 12 processed at one end of the split material 3 and the finger joint 12 processed at both ends of the split material 3 are also used. .

Next, in the joining step S4, the small openings 4 of the split material 3 are connected to each other. This connection can be made by applying a water-based vinyl adhesive or the like to the finger joint 12 and engaging and joining the finger joints 12 together. By joining in the longitudinal direction, a long material 5 as shown in FIG. 5C can be obtained. As the long material 5, two types of materials in which the joint portions of the split material 3 by the finger joints 12 are shifted from each other are produced. For this reason, in the embodiment of FIG. 5C, there are three types of subdivisions of length L ₅ (= 1200 mm), length L ₆ (= 850 mm), and length L ₇ (= 250 mm) with different lengths. By using the materials 3 and combining them as shown in FIG. 5C, two types of long materials 5 having a total length of 4100 mm are produced.

Next, in the long laminating step S <b> 5, a plurality of the long materials 5 are laminated to produce a long laminated material 6. In the embodiment of FIG. 6 (a), two long members 5 are bonded with an adhesive such as aqueous vinyl, and pressed to obtain a length L ₈ (= 4100 mm) and a width L ₄ (= 120 mm). ), A long laminate 6 having a thickness D ₂ (= 40 mm) is produced. Since the long materials 5 to be laminated here are made so that the joint portions by the finger joints 12 are not shifted and overlapped, it is possible to obtain the long laminate materials 6 that are difficult to break at the joint portions even when a bending load is applied. It can be done.

Next, in the dividing step S6, the long laminated material 6 is cut along the longitudinal direction to be divided into a wooden laminated material B having a substantially square cross section. In the embodiment of FIG. 6 (b), the longitudinal laminate 6 has a length L ₈ (= 4100 mm) and a longitudinal and transverse dimension by cutting the long laminated material 6 with a cutter 11 or the like so as to be divided into three equal parts in the width direction. A wood laminate B of L ₉ (= 40 mm) is produced.

  Then, in the cutting step S7, the outer peripheral surface of the wood laminate B is cut, and the cross-sectional shape is processed into a circle or an ellipse, thereby finishing it into a round bar having a diameter of about 35 mm. As shown in FIG. B can be obtained. For example, as shown in FIG. 6C, the cutting of the outer peripheral surface of the wood laminate B is performed by pressing the cutting tool 13 against the outer periphery of the wood laminate B while rotating the wood laminate B around the axis. Can be done. The round bar A is shipped as a product through an inspection step S9 for inspecting warpage, length, defects, etc. after sanding the outer peripheral surface in the sanding step S8 and cutting it to a predetermined length. .

  In the round bar A as shown in FIG. 1 formed as described above, the single plate 1a made of high-density wood and the single plate 1b made of low-density wood are alternately arranged on a plane parallel to the longitudinal direction. As described above, the single plate 1a having a high density has a small deflection when a bending load is applied, and the single plate 1b having a low density is a plate having a bending load. Since the bending strength until failure is high, a round bar A having a high strength and a small deflection with respect to a bending load can be obtained by a synergistic action of these characteristics.

  The invention will now be illustrated by means of examples.

(Example 1)
The eucalyptus material having a thickness of 1.4 mm is used as the high density single plate 1a, and the poplar material having a thickness of 1.6 mm is used as the low density single plate 1b. A single plate laminate 2 was prepared by the method described above. Next, this single-plate laminated material 2 was processed by the above-described method shown in FIG. 5 and FIG. Then, the outer peripheral surface of the wood laminate B was cut into a circular cross section to obtain a round bar A having a diameter of 35 mm and a length of 1200 mm as shown in FIG.

(Example 2)
A eucalyptus material with a thickness of 1.6 mm is used as the high density single plate 1a, and a poplar material with a thickness of 1.8 mm is used as the low density single plate 1b. A round bar A was obtained in the same manner as in Example 1 except that it was prepared.

(Example 3)
A single plate laminating material 2 is formed by alternately stacking 5 sheets of eucalyptus material having a thickness of 2.3 mm as the single plate 1a having a high density and using a poplar material having a thickness of 2.3 mm as the single plate 1b having a low density. A round bar A was obtained in the same manner as in Example 1 except that it was prepared.

(Comparative Example 1)
A round bar A was obtained in the same manner as in Example 1 except that only a poplar material having a thickness of 2.0 mm was used as the veneer 1 and 11 sheets thereof were laminated to produce the veneer laminate 2.

(Comparative Example 2)
A round bar A was obtained in the same manner as in Example 1 except that only a eucalyptus material having a thickness of 2.0 mm was used as the veneer 1 and 10 sheets thereof were laminated to produce the veneer laminate 2.

  As described above, a vertical load test was performed on the round bars A obtained in Examples 1 to 3 and Comparative Examples 1 and 2 based on the BL standard. In the test, the round bar A is attached by mounting brackets with an interval of 900 mm, the load is continuously applied to the round bar A in the vertical direction with the center of 900 mm as the applied point, and the round bar A breaks. The maximum load value and the amount of deflection of the round bar A were measured. The results are shown in Table 1. In addition, the test was done also about the round bar of the same dimension produced from the laminated material of the tamo material (comparative example 3).

  As seen in Table 1, Examples 1 to 3 having a structure in which high density single plates made of eucalyptus and low density single plates made of poplar are alternately laminated are only single plates of poplar material. The load at break was higher than that of Comparative Example 1 in which the structure was laminated and the amount of bending was small, and the load at break was higher than that of Comparative Example 2 in which only a single plate of eucalyptus was laminated. . Further, it was confirmed that a round bar having mechanical properties equivalent to those of Comparative Example 3 made of Tamo laminated material and having high strength against bending load and small deflection is obtained.

  In addition, from the comparison of Examples 1 and 2 and Example 3, by setting the thickness of the low density single plate thicker than that of the high density single plate, the bending strength is more than when the thickness is set to be the same. It is confirmed that the deflection can be made higher and smaller.

It is a partial perspective view showing an example of a round bar concerning the present invention. It is a flowchart of the process of manufacturing a round bar. The manufacturing process same as the above is shown, and (a) and (b) are perspective views. The manufacturing process same as the above is shown, and (a) and (b) are schematic enlarged cross-sectional views, respectively. The manufacturing process same as the above is shown, and (a) to (c) are perspective views. The manufacturing process same as the above is shown, and (a) to (c) are perspective views.

Explanation of symbols

A Round bar B Wood laminate 1 Single plate 1a High density single plate 1b Low density single plate

Claims (3)

  A round bar characterized in that it is formed of a wood laminate in which single plates having different densities are alternately laminated and the outer periphery is cut into a round bar shape.   The round bar according to claim 1, wherein the wood laminate is formed by using a single plate having a low density that is thicker than a single plate having a high density.   The round bar according to claim 1 or 2, wherein a single plate made of eucalyptus material is used as the single plate having a high density, and a single plate made of poplar material is used as the single plate having a low density.

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