| 摘要 |
In a lid member having a long and short edge plate portions which are adjacent to each other, and approximately formed as an L-shaped form in its cross section, the long edge plate portion has a plurality of first groove portions which extend approximately in parallel to a ridge line portion which is held in common with the short edge plate portion adjacent in a width direction so as to be arranged side by side while being spaced from each other, and are formed so as to be concaved to a back side in a thickness direction in relation to an upper surface, and a plurality of second groove portions which are formed so as to be concaved to the back side in the thickness direction in relation to the upper surface, and are connected both end portions in a length direction respectively to a plurality of first groove portions. |
| 主权项 |
1. A lid member comprising:
a first plate portion having a predetermined thickness, and having a first surface defining an upper surface of the lid member and a second surface opposite to the first surface; a second plate portion having a predetermined thickness, and having a third surface defining a side surface of the lid member and a fourth surface opposite to the third surface; the first plate portion and the second plate portion being adjacent to each other; and the lid member being approximately formed as an L-shaped form in cross section, said first surface being substantially perpendicularly in relation to the third surface, and said first surface being contiguous to the third surface, said second surface being substantially perpendicularly in relation to the fourth surface, and said second surface being contiguous to the fourth surface, said first and second plate portions having a ridge line portion at a boundary of said first and third surfaces, length directions of the first and second plate portions being in parallel to a length direction of the ridge line portion, and wherein said first plate portion has a plurality of first groove portions which extend approximately in parallel to said ridge line portion so as to be arranged side by side while being spaced from each other, and said plurality of first groove portions are formed so as to be concaved to said second surface side in relation to the first surface, and wherein said first plate portion has a plurality of second groove portions which are formed so as to be concaved to said second surface side in relation to the first surface, said plurality of second groove portions being connected at both end portions in a length direction respectively to said plurality of first groove portions, a height position of a groove bottom surface of the first groove portions being aligned with a height position of a groove bottom surface of the second groove portions, and wherein said plurality of second groove portions contain a first group of groove portions arranged closer to both ends portions in the length direction of said first plate portion and a second group of groove portions arranged closer to a center position in the length direction of said first plate portion, and wherein the first group of groove portions and the second group of groove portions are set in respective length directions so that an angle from said ridge line portion has a smaller incline in the first group of groove portions than in the second group of groove portions. |
