| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to provide a duplex writing utensil at low cost, by a method wherein the tips of a plurality of writing bodies are selectively made to be retractable from and extendable through the tip hole of a front shaft by turning a rear shaft and, at the same time, the retracting and extending of a rubber eraser are made possible by turning a top crown. SOLUTION: A rear shaft 4, which covers a cylindrical cam 5, is fixed only rotatably at the center shaft 1. In addition, a clip is fixedly provided on the outer peripheral side surface of the rear shaft and an engaging part 4b is provided at the tip spherical part of the clip. On the peripheral surface opposing to the inside of the clip of the rear shaft, an axially elongated window part is bored so as to project the engaging projection 21 provided on the outer peripheral surface part of a cylindrical cam and engage with the engaging part of the spherical part of the clip. The cylindrical cam 5 is rotationally stopped and positioned forward and backward movably. When the engaging projection engages with the engaging part of the spherical part of the clip at the advanced position of the cylindrical cam, respective sliding pieces 6 are alternately moved back and forth by turning the rear shaft to the center shaft, resulting in allowing to selectively project the tips of respective writing bodies from the tip hole of a top shaft. |
