| 摘要 |
<p>The device has fixation units (32, 34) integrated to a cover and a swimming pool (10), respectively, where the units are adapted to occupy disengaged and locked states. The cover is free from a force exerted from top to bottom and responsive to a stream line (14) and the units are moved to prohibit a units' co-operation by mechanical coupling when the units are in the disengaged state. The cover is subjected to displacement from the top to the bottom under a force action, to avoid the movement of the units and the units are co-operated by the coupling, when the units are in the locked state.</p> |
