| 摘要 |
PROBLEM TO BE SOLVED: To feed an eraser in response to its wear by a simple operation by locking a barrel to a rear barrel at forwarding or retracting position so that the barrels are matched at the forwarding position to grasp an eraser at a locking protrusion and a hinge is exposed from a rear end of a rear barrel at the retracting position with the result that the barrel is expandable. SOLUTION: A barrel 38 has a bottom 38b, two split barrel portions 40 along an axially central direction substantially centrally rear. The portions 40 are coupled by thin hinges 39 so as to be openable and closable. Further, a plurality of stepwise eraser locking protrusions 40a are formed along the axially central direction at an inside of the cylinders 40. An eraser clamper 31 is locked movably at forwarding or retracting position to a rear axis in such a manner that a protrusion 38a is guided by and inserted into a groove 36 of a rear barrel 4 and engaged with a slit 32 by utilizing a deformation of an elastic piece. The clamper 37 is brought into contact with a stepped portion 35 at a rear end of the protrusion 38a at the retracting position to inhibit its removal and brought at the bottom 38b into contact with the stepped portion at the forwarding position. |
