| 摘要 |
PROBLEM TO BE SOLVED: To provide a pit lid having a simple structure and achieving both weight saving and strength, without being floated up due to buoyant force generated when a train passes through the side of the pit lid. SOLUTION: A pit lid 1 comprises: a top board part 3 in an approximately rectangular plate state; ribs provided on the backside of the top board part 3; handles 5 provided on both ends of the pit lid in the width direction; and the like. On the backside 1b of the pit lid 1, multiple width direction ribs 7a formed in the width direction of the pit lid 1 are formed and multiple longitudinal direction ribs 7b formed in the longitudinal direction of the pit lid 1 and approximately perpendicular to the width direction ribs 7a are formed. In this case, when making portions surrounded by the width direction ribs 7a and the longitudinal direction ribs 7b as spaces, spaces arranged at both ends of the pit lid 1 in the width direction become spaces 11a opening outward in the width direction of the pit lid 1. Namely, the space 11a is formed so as to be opened only to the bottom surface side and one side surface side of the pit lid 1. COPYRIGHT: (C)2012,JPO&INPIT |
