| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a ballpoint pen tip wherein no phenomenon of buckling of a coil spring occurs and which prevents application of a deviated pressing force, instead of application of pressure to the center of a ball, and prevents failure to obtain a set pressing force. <P>SOLUTION: The ball is put on the bottom wall of a ball holding chamber of the main body of the tip and the fore end of the tip is calked inward so that the ball is held rotatably in a state of a part thereof being exposed outward from the fore end of the tip, while the ball is pressed against the inner wall surface of the fore end of the tip by the resilience of a coil part of the coil spring. In this ballpoint pen tip, a reduced diameter part contacting with the ball and having a smaller outside diameter than the coil part is formed in the fore end of the coil spring, and the diameter of the connecting part of the reduced diameter part and the coil part is made smaller gradually by a diameter being smaller than the wire diameter of the coil spring so that the connecting part is formed in a slanting shape, while the reduced diameter part and the connecting part of the coil part and the reduced diameter part are so constituted as to form close contact winding. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
