| 摘要 |
A well covering consisting of a ring (10) and a cover (13) resting on an inner shoulder (12) in the ring. On a place on its circumference, the cover engages under the shoulder, and on the diametrically opposite side, the cover has a hook (19) on the circumference for engagement with the middle section of a spring-mounted rod (23) located along a chord in the ring, that is attached to the ring at its ends. An opening (24) is located in the cover above the rod so that it can be moved elastically to disengage with the hook via a tool inserted into the hole.<IMAGE> |
