DEVICE FOR LOCKING AND UNLOCKING A COVER IN PARTICULAR OF A MANHOLE WITH THE AID OF A KEY
The present invention relates to a device for locking and unlocking a cover on a frame in particular of a manhole with the aid of a key. According to the invention, the device is characterized in that the bolt (14) of the lock (13) comprises two radial fingers (17) that are aligned in a direction parallel to a flat web (4) of the cover (3) and are able to cooperate, when the cover (3) is in a position closing the frame (2), with two ramps (36, 41) that are integral with the frame (2) and the cover (3), respectively, so as to exert on the cover (3) a force for locking to the frame (2), said force increasing as the fingers (17) of the bolt (14) move over the ramps (36, 41) until the fingers (17) are in their position locking the cover (3) to the frame (2), in which one of the two fingers (17) of the bolt (14) is trapped in the strike (16) of the frame (2). The invention is applicable in the field of highway equipment.