Patent ID: 8079767

Claim:
A fixed-nib writing instrument having a shaft extending along a longitudinal axis and at the front of which a protective sleeve is mounted such that it can move coaxially with respect to the shaft, the sleeve moving between a protecting position in which it covers the writing nib and a retracted position in which it enables writing, the sleeve comprising a wall section which includes at least one helical guide path in engagement with at least one peg connected to the shaft in order that a rotation of the sleeve causes the latter to slide translationally between the protecting position and the retracted position, wherein the at least one peg is designed to be resiliently retractable in order that it can snap into the helical guide path with which it engages, and wherein means for holding the rotation of the sleeve are provided to prevent the sleeve from rotating below a certain force threshold in the protecting position and the retracted position, the holding means comprising at least one protruding element designed to be inserted resiliently in a first groove and in a second groove in the protecting position and the retracted position, respectively.