Abstract: In one embodiment, a writing instrument refill includes a first portion having flexibility, and a second portion having a cross-sectional area larger than a cross-sectional area of the first portion, wherein the center of figure of the cross section of the first portion is offset from the center of the figure of the cross section of the second portion, the first portion and the second portion are formed integrally, and a part of the first portion has an outer diameter smaller than an outer diameter of the other part of the first portion.

Abstract: A method for manufacturing a ball pen tip, in which a spring for biasing a ball is assembled to the ball pen tip, includes punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble the spring to the ball pen tip by the plastic flow ridge.

Abstract: 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.

Abstract: A mechanical pencil includes a writing lead, a chuck that chucks the writing lead and feeds the writing lead forward, and a shaft tube for housing the writing lead and the chuck. When a click operation for feeding the chuck forward is performed, a jet stream flowing forward is generated inside the shaft tube.

Abstract: A hand tool includes an outer barrel, an inner barrel housed in the outer barrel, and a rear barrel assembled to the outer barrel and the inner barrel. One of the outer barrel and the inner barrel includes a cam follower protruding in a radial direction of the hand tool, the other of the outer barrel and the inner barrel includes a cam groove engaging with the cam follower, and the cam follower is supported to be movable in a radial direction.

Abstract: A method for manufacturing a ball pen tip in which a spring for biasing a ball is assembled to the ball pen tip, the method including punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by a plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble the spring to the ball pen tip by the plastic flow ridge.

Abstract: In an embodiment, a fluid container includes a container main body that has a tank housing a fluid; a fluid discharge body disposed on a front end portion of the container main body that discharges the fluid through a discharge port formed in a front end portion thereof; a plunger including an operating body that pushes out the fluid in the tank to the fluid discharge body in a predetermined amount corresponding to an operation of the operating body; and a valve that closes a connecting flow passage connecting the tank to the fluid discharge body and opens the connecting flow passage when the plunger pushes out the fluid, the valve including a valve seat surface, a valve body disposed in front of the valve seat surface to abut the valve seat surface from the front, and a spring biasing the valve body toward the valve seat surface.

Abstract: A mechanical pencil 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.

Abstract: A composite writing implement according to an embodiment includes a barrel, writing shafts housed in the barrel, a cam main body including a cam projection, an end surface extending along the cam projection, and a latch recess provided in the cam projection, and sliders configured to be connected to respective rear ends of the writing shafts, and include a cam configured to be latchable to the latch recess, and have a sliding contact surface to be pressed against the end surface, wherein the end surface includes a first inclined portion that is positioned on the front end side of the cam projection and is inclined by a first incline angle, and a second inclined portion that is positioned further toward the rear end side of the cam projection than the first inclined portion, and is inclined by a second incline angle that is larger than the first incline angle.