Lukituslaitteisto kiertoniveltä varten

The present invention relates to a locking system for a rotating joint. In the device, the locking system (L) comprises a rigid locking means (12) movable in the axial direction (X1), provided with a first cogging (13) which can be moved for locking with the locking means (12) in a contact with a second cogging (14), to transmit the rotational movement, wherein said coggings (13, 14) are, for releasing the cogging, designed in such a way that a force effect releasing the locking is formed between them, and a third cogging (16) which is, during the locking, in a contact with a fourth cogging, to transmit the rotational motion, as well as a sealing element (21) for forming at least one closed hydraulic space (24) with a varying volume between the locking means (12) and the sealing element (21), wherein the locking means (12) is arranged to be moved for the locking and to be kept in the locking by the effect of a pressurized medium.