DEVICE FOR LOCKING AND UNLOCKING A MANHOLE COVER ON A FRAME BY MEANS OF A KEY, WITH THE OPTION OF AUTOMATIC KEYLESS LOCKING OF SAID MANHOLE COVER ON THE FRAME

摘要

The present invention relates to a device for locking and unlocking a manhole cover on a frame by means of a key, with the option of automatic keyless locking of said manhole cover on the frame. According to the invention, the device is characterised in that the bolt (11) of the lock (5) comprises a shank (11a) returned to the captive position of the strike (12) by a resilient return member (14) and the drive mechanism (10, 25) engages with the bolt (11) so as to allow the automatic locking of the manhole cover (1) to the frame (2) when the key is removed from the manhole cover (1) in the position thereof separated from the opening of the frame (2), and the manhole cover (1) comprises a captive plug (34) for sealing the through-opening (4) of the manhole cover (1).