| 摘要 |
PROBLEM TO BE SOLVED: To realize the stable fitting of a barrel back part by an inner cap as well as a spring wig when a cap is fitted to the cylinder back part by providing a predetermined number of axial slits for releasing the opening end of the inner cap at its opening end part so as to form a plurality of tongue pieces, which are rockable and elastically urging the barrel back part. SOLUTION: The opening part of an inner cap 6 is made to be slightly smaller in a diameter. By axially slitting an opening end for opening, a smaller diametral part consisting of two tongue pieces 14 is provided. Further, at the part (the left in a figure) inner than the tongue pieces 14 of the inner cap 6, the one end part of a supporting member 15 made of a thin walled metal tube is fixed to its outer surface so as to be made nearly flush with the outer surface of the inner cap 6, while its other end part projects beyond the opening end of the inner cap 6. To the tip part of the opening end of the supporting member 15, an inward fin-like annular elastic member 16 is fixed so as to form a constitution for sealing the interior of a pen point housing part through the urging deformation of the outer peripheral surface of a neck part 2. Further, by forming a gap g between the tongue pieces 14 and the supporting member 15, the slight swinging of the tongue pieces 14 can be allowed. |
