| 摘要 |
PROBLEM TO BE SOLVED: To prevent the use of lumber other than thinnings as the stile material of a board for the purpose of conserving forest resources. SOLUTION: The stile material 11 of the board is constituted of a synthetic resin material (Fig. A) so as to prevent the use of any lumber as the material 11. When a foamed synthetic resin material foamed to an extent of foaming of 1.05-4 is used for constituting the material 11, the set screws 3 of a frame member 12 can be screwed in easily and, in addition, required strengths are obtained. When glue reservoirs 11a are provided, the adhesive used for sticking surface boards 1a and 1b does out ooze out to the periphery of the board. In addition, when chamfered sections or Rs 11b are provided, the occurrence of 'abnormal appearances of surface boards 1a and 1b' corresponding to the boundary lines between a core material and the stile material 11 can be eliminated.
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