Abstract: An anti-unscrewing device for coupling the tubular ends of two components in fluid conveying or delivery systems by means of a threaded ring nut that can be screwed to one of said tubular ends to connect said ends, wherein said anti-unscrewing device comprises a connecting portion to connect the device to one of the components and at least one counter element provided with an engaging portion suitable to engage a corresponding engaging surface formed at said ring nut, such that the engaging portion can be displaced by means of a movement of the ring nut. There are further provided guide means dictating a movement path for the counter element, such that an unscrewing movement of the ring nut will cause the engaging portion to move to a locking position relative to the ring nut thereby preventing the ring nut from unscrewing.

Abstract: The invention concerns a channel element (1) for roadway drainage gutter, consisting of a thermoplastic trench body (2) with U-shaped cross-section whereof the horizontal upper ends of the branches (2a) are designed to receive a metallic rabbet (3) for receiving and maintaining a metal grate (4) fixed to the channel body (2) with fixing means such as a screw (9)/nut (10), the trench body (2) including at least a bore (6) arranged at the horizontal upper ends of its branches (2a) to be aligned with matching orifices (7, 8) provided respectively in the rabbet (3) and in the grid (4) for receiving, preferably with clearance, a screw for fixing (9) the grid. Another bore (11) of smaller diameter than the diameter of the screw (9) is provided beneath said housing.