CONTROL OF ACCESS TO MANHOLES
A locking mechanism for locking a manhole cover in place is disclosed together with a key for opening and closing the locking mechanism. The key (64) includes a source (90) of electrical power, an electrically conductive loop (76) and means for supplying power to the loop so that it resonates. The locking mechanism includes electrically powered means (22, 23, 24) for shifting a locking element (26) of the locking mechanism between locked and unlocked positions. An electrically conductive loop (36) tuned to resonate with the loop (76) of the key is provided so that power can be transmitted from the loop (76) of the key to the loop (36) of the locking mechanism.