A writing instrument according to an embodiment of the invention including, a chuck that chucks a writing lead, wherein the chuck includes a first chuck pawl which comes into point contact or line contact with the writing lead to press the writing lead so as to apply first contact stress to the writing lead; and a second chuck pawl which presses the writing lead so as to apply, to the writing lead, second contact stress that is lower than the first contact stress, and the first contact stress is configured such that, when a prescribed impact is applied to the writing lead, a contact portion of the writing lead subjected to the first contact stress fractures and absorbs the prescribed impact.

An anti-rotation mechanism for a retractable eraser or other stick-like object for use with a writing instrument that utilizes locking elements to prevent the inadvertent retraction or extension of the eraser when pressure is applied to the eraser during the erasing operation.

An anti-rotation mechanism for a retractable eraser or other stick-like object for use with a writing instrument that utilizes locking elements to prevent the inadvertent retraction or extension of the eraser when pressure is applied to the eraser during the erasing operation.

A mechanical pencil according to an embodiment includes: a barrel; a cushion spring that has a rear end supported by the barrel; a sleeve that is biased forward in an axial direction by the cushion spring and movable in a direction perpendicular to the axial direction by an impact applied from outside of the barrel in an elastically supported state; a chuck spring that has a front end supported by the sleeve; a chuck that chucks a writing lead for a mechanical pencil; a writing lead tube that is fitted to the chuck and biased rearward in the axial direction together with the chuck by the chuck spring; and a contact sliding part that suppresses movement of the sleeve in the direction perpendicular to the axial direction.

A mechanical pencil according to an embodiment includes: a barrel; a cushion spring that has a rear end supported by the barrel; a sleeve that is biased forward in an axial direction by the cushion spring and movable in a direction perpendicular to the axial direction by an impact applied from outside of the barrel in an elastically supported state; a chuck spring that has a front end supported by the sleeve; a chuck that chucks a writing lead for a mechanical pencil; a writing lead tube that is fitted to the chuck and biased rearward in the axial direction together with the chuck by the chuck spring; and a contact sliding part that suppresses movement of the sleeve in the direction perpendicular to the axial direction.

A mechanical pencil includes a barrel extending in a longitudinal direction, a lead-propelling mechanism, a lead reservoir, a side button, and an eraser-propelling mechanism having a helical cam. The lead-propelling mechanism, the lead reservoir, the eraser-propelling mechanism, and the side button are at least partly housed inside the barrel. The lead-propelling mechanism, the lead reservoir, and the eraser-propelling mechanism are prevented from rotating about the longitudinal direction relative to one another and relative to the side button, and the side button is prevented from rotating about the longitudinal direction relative to the barrel.

A mechanical pencil includes a barrel extending in a longitudinal direction, a lead-propelling mechanism, a lead reservoir, a side button, and an eraser-propelling mechanism having a helical cam. The lead-propelling mechanism, the lead reservoir, the eraser-propelling mechanism, and the side button are at least partly housed inside the barrel. The lead-propelling mechanism, the lead reservoir, and the eraser-propelling mechanism are prevented from rotating about the longitudinal direction relative to one another and relative to the side button, and the side button is prevented from rotating about the longitudinal direction relative to the barrel.

A mechanical pencil unit is provided which includes: a holding tube; a holder which is inserted into a front side opening portion of the holding tube and which protrudes forward from a front end of the holding tube, and moreover which is supported so as to be back and forth movable relative to the holding tube; a pencil lead delivering mechanism which delivers forward a pencil lead x inserted into the holder; and a movement direction conversion mechanism which causes the holder to go forward relative to the holding tube and the pencil lead x by using a force applied in a radial direction from the pencil lead x to the holder, wherein the pencil lead delivering mechanism is provided at a position further toward a rearward side than the holder and the movement direction conversion mechanism.

A stylus includes in a tubular casing a core body, a pressure detector that detects a pressure applied to the core body, a coupling fitted over the core body, the coupling transmitting the pressure to the pressure detector, and a core pressing controller that controls the coupling to press the core body axially in the tubular casing. The coupling includes a push bearer that bears a push from the core pressing controller, a presser having an axial end fitted in the pressure detector, a fitting region fitted over a portion of the core body remote from a pen tip end of the tubular casing, a receptacle in which another end of the presser remote from an axial end thereof is axially movably housed, and an elastic member disposed in the receptacle, the elastic member biasing the other end of the presser resiliently toward an axial pen tip end of the receptacle.

A mechanical pencil and an operating method therefor. A position-based relationship of a tool body is determined by means of the displacement of an adjustment part provided in a sleeve. The tool body has two position-based states, which are retracted and propelled states, and the adjustment part achieves relative stability at the two position-based states by means of a positioning part or a positioning slot in the sleeve, a resetting part, and a control part. The resetting part is driven by the tool body to provide a continuous force to the adjustment part, so that the state of a displacement part on the adjustment part is relatively stable at a retracted position. When the displacement part moves in the positioning slot to a propelled position, the displacement part is limited by the control part, so that the state at the propelled position is relatively stable.