| 摘要 |
The manhole cover comprises a ring 10 and a lid 13, which rests on an internal shoulder 12 in the ring and with a section 14 on the inner side of the lid running into the ring. In an external annular groove 15 in the said section, which is enclosed by the manhole ring with clearance, a locking ring 16 made of elastic material is fitted, which locking ring pulls out in the form of a collar and is tiltable in the groove and can be placed by its inner periphery against the bottom of the groove. The outer periphery of the locking ring can be placed against the inner side 17 of the manhole ring in order, when the lid is introduced into the manhole ring, accompanied by tilting motion in the groove, to be swept aside or upwards by the inner side of the manhole ring. In this position, the locking ring prevents the lid from being lifted from the manhole ring as it engages with the inner side thereof. <IMAGE> |
