Patent ID: 11927040
Assignee: FILOBE CO., LTD.
Field: Civil engineering (Other fields)
Classification: CPC E | IPC E

Claim 1:
2. The apparatus according to claim 1, characterized in that,
in case that the first vertical contact surfaces (1510a) and (1510b) provided to the first vertical support (1510) are convex contact surfaces (1510a), the second vertical contact surfaces (1520a), (1520b) provided to the second vertical support 1520 is formed by a concave contact surface (1520a); and
in case that the first vertical contact surfaces (1510a) and (1510b) provided to the first vertical support (1510) are concave contact surfaces (1510b), the second vertical contact surfaces (1520a), (1520b) provided to the second vertical support 1520 is formed by a convex contact surface (1520b).