A mechanical pencil includes a writing lead, a chuck unit for chucking the writing lead, and a cushion spring configured to elastically support the chuck unit in such a manner that the chuck unit is retractable with a writing pressure. An output of the cushion spring, in response to a cushion stroke, is non-linear, and a slope of a spring constant, in a region where the cushion stroke is relatively small, is smaller than a slope of a spring constant in a region where the cushion stroke is relatively large.

A mechanical pencil includes a writing lead, a chuck unit for chucking the writing lead, and a cushion spring configured to elastically support the chuck unit in such a manner that the chuck unit is retractable with a writing pressure. An output of the cushion spring, in response to a cushion stroke, is non-linear, and a slope of a spring constant, in a region where the cushion stroke is relatively small, is smaller than a slope of a spring constant in a region where the cushion stroke is relatively large.

A side-knock type mechanical pencil comprising a body with a side-mounted knock button coupled to the body of the mechanical pencil and adapted to slidingly engage with a lead tube with a frustoconical hub for translating the motion of the knock button actuation to linear extension of the lead.

A side-knock type mechanical pencil comprising a body with a side-mounted knock button coupled to the body of the mechanical pencil and adapted to slidingly engage with a lead tube with a frustoconical hub for translating the motion of the knock button actuation to linear extension of the lead.

A writing instrument includes a barrel, a tip, and a cushion spring that elastically supports the tip in the axial direction to the barrel. The cushion spring is formed as one piece by injection molding, the cushion spring includes an aperture on its outer peripheral surface, and a displacement regulating protrusion that protrudes and extends into the aperture along the axial direction. The protrusion prevents the cushion spring from compression beyond a prescribed length.

A writing instrument includes a barrel, a tip, and a cushion spring that elastically supports the tip in the axial direction to the barrel. The cushion spring is formed as one piece by injection molding, the cushion spring includes an aperture on its outer peripheral surface, and a displacement regulating protrusion that protrudes and extends into the aperture along the axial direction. The protrusion prevents the cushion spring from compression beyond a prescribed length.

An adjustment pen, including a pen body, the pen body including a pen tip, wherein the adjustment pen further includes a light emitting unit, a control switch and a power supply module which are carried by the pen body, the light emitting unit is connected with the control switch and the power supply module to form an illumination circuit, the control switch is configured to control ON and OFF of the illumination circuit, and the light emitting unit is configured to emit a light beam toward the pen tip.

An adjustment pen, including a pen body, the pen body including a pen tip, wherein the adjustment pen further includes a light emitting unit, a control switch and a power supply module which are carried by the pen body, the light emitting unit is connected with the control switch and the power supply module to form an illumination circuit, the control switch is configured to control ON and OFF of the illumination circuit, and the light emitting unit is configured to emit a light beam toward the pen tip.

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.