| 摘要 |
A mechanical pencil having a writing point tube slidably mounted on the forward end portion of a pencil casing, an annular slider device slidably mounted within the pencil casing and having a lead retainer, a first spring for urging the writing point tube in the forward direction, a collet chuck mechanism having a lead engaging collet and a chuck-actuation cylinder, a second spring urging both the lead engaging collet and the chuck-actuation cylinder in the opposite direction and a third spring for urging the collet chuck mechanism in the forward direction. The pencil has a locking device for temporarily engaging the slider at its retracted position, and a pusher for releasing the engagement of the slider. When an axial thrust is applied to the writing tip of the pencil for lead advancement, the slider and the collet chuck mechanism as well are retracted within the pencil casing with their positional relation being unchanged. When the thrust against the writing tip is released, the collet chuck mechanism is advanced at first with the lead grasped therein to feed the lead out of the lead tube while the slider is temporarily engaged at its retracted position, and thereafter the pusher abuts against the slider to unlock it so that the slider advances by the effect of the first spring with the lead projecting from the lead tube.
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