Abstract: This invention concerns a screw for the anti-fraud locking of a throttle or clamp lever on the control rod of a valve shutter or stopcock, comprising a threaded shank having a polygonal head surmounted by a truncated-cone shaped dome, semi-spherical or of other shape, the base of which extends over the edge of the perimeter surface of said polygonal head, where said dome is free to turn around the shank above said polygonal head, so that only by means of a special tool can the threaded screw shank be tightened or loosened by means of the nut, while by operating on the dome with any tool or utensil, no effect is achieved as this is able to turn idly around the threaded shank.

Abstract: This invention concerns a screw for the anti-fraud locking of a throttle or clamp lever on the control rod of a valve shutter or stopcock, comprising a threaded shank having a polygonal head surmounted by a truncated-cone shaped dome, semi-spherical or of other shape, the base of which extends over the edge of the perimeter surface of said polygonal head, where said dome is free to turn around the shank above said polygonal head, so that only by means of a special tool can the threaded screw shank be tightened or loosened by means of the nut, while by operating on the dome with any tool or utensil, no effect is achieved as this is able to turn idly around the threaded shank.

Abstract: The invention concerns a valve or tap for fluids, with a stopper that rotates controlled by a control rod equipped with a throttle or grip lever fixed to said rod by means of a fastening screw. The throttle or grip lever has at least one blocking notch (19, 20), designed to fit tightly with a catch (18), which is part of the valve body in order to prevent the stopper from turning. The fastening screw (15) has a special head that allows it to be screwed/unscrewed only with a specific wench or tool, thereby preventing tampering.