CAP-LESS WRITING INSTRUMENT

摘要

The invention relates to a writing instrument comprising a barrel (2), a writing member (3) with a tip (35) capable of displacement between retracted and exposed positions, a sealing sleeve (40) capable of displacement in the barrel between backward and forward positions when driving the writing member, and a shut-off device (52) for blocking the front opening (41) of the sleeve when said sleeve is in a retracted position and the tip (35) is inside. The sleeve comprises a first engagement portion (43) on the inner face thereof and the writing member comprises a second engagement portion (46) on the outer face hereof. The engagement portions (43, 46) are arranged for frictional engagement one with the other in order to create a linking force that is higher than the strength required for displacing the sleeve and in order to create a sealed annular area when the writing member and the sleeve are in retracted and backward positions. One of the engagement portions consists of a frustoconical surface.