| 摘要 |
PROBLEM TO BE SOLVED: To prevent fraudulence from being applied to the external frame which is formed of a material made of an aluminum alloy. SOLUTION: A lower frame plate (6) is bridged on the external frame body section (1) which is constituted to be a rectangular shape of top and bottom lateral frames (2 and 3) and right and left vertical frames (4 and 5) with aluminum as the material, and the inside is partitioned into an internal frame housing frame section (1A) and a front decorative plate fitting frame section (1C). On the respective internal surfaces of the lateral frame (2), the right and left vertical frames (4 and 5) of the internal frame housing frame section (1A), and the lower frame plate (6), ribs (8, 9, 10 and 11) are projected along the lengths. Then, end parts at which the ribs are butted to each other are integrally connected at the corner parts of the internal frame housing section. A fraudulence preventing wall (14) which forms an annular shape is formed on the inner periphery of the internal frame housing section. The fraudulence preventing wall (14) is made to attend toward the outer peripheral surface of an internal frame (7) which is closed and joined to the internal frame housing section (1A), and thus, a fraudulent utensil such as a piano wire being inserted into a space between the external frame and the internal frame is prevented from entering. COPYRIGHT: (C)2007,JPO&INPIT
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