Projectable and retractable writing tool

A shaft cylinder for a projectable and retractable writing tool, the shaft cylinder being capable of containing a tip holder such that the tip holder is movable in an axial direction, a tip being fixed to a front end of the tip holder, the shaft cylinder having an opening at a front end thereof, through which the tip is projectable and retractable in conjunction with a movement of the tip holder, the shaft cylinder comprising,

• an annular member loosely fitted onto an inner periphery of the opening of the shaft cylinder to be movable in an axial direction of the shaft cylinder with respect to the shaft cylinder, and
• an elastic member capable of connecting the tip holder and the annular member such that the tip holder and the annular member are movable relatively to each other,
• wherein
• a contact surface is formed on at least a part of an outer periphery of the annular member, the contact surface being configured to come into contact with a part of the inside surface of the shaft cylinder in conjunction with the movement of the tip holder toward the front end side,
• a cutout is formed at a part of the annular member such that an inner diameter of the annular member is reduced when a load is received by the contact surface,
• a guide surface is formed on the part of the inside surface of the shaft cylinder, the guide surface being configured to come into contact with the contact surface in conjunction with the movement of the tip holder toward the front end side, and
• the contact surface is configured to receive the load from the guide surface in conjunction with the movement of the tip holder toward the front end side.