A mechanical pencil includes a ball chuck, a rotation drive mechanism having a rotary part, a feedout cam face having a step part in the axial direction, an input member rotating upon receiving a rotational drive force of the rotary part, and an output member having an abutting part abutting against the feedout face and a slider provided with a holding chuck holding lead, the abutting part moves along the feedout face corresponding to rotation of the output member and so that advancing motion of the slider when the abutting part drops into the drop difference causes lead held by the holding chuck to be pulled out by the ball chuck, and further including a clutch mechanism transmitting rotational movement of the input member to the output member.

A mechanical pencil includes a ball chuck, a rotation drive mechanism having a rotary part, a feedout cam face having a step part in the axial direction, an input member rotating upon receiving a rotational drive force of the rotary part, and an output member having an abutting part abutting against the feedout face and a slider provided with a holding chuck holding lead, the abutting part moves along the feedout face corresponding to rotation of the output member and so that advancing motion of the slider when the abutting part drops into the drop difference causes lead held by the holding chuck to be pulled out by the ball chuck, and further including a clutch mechanism transmitting rotational movement of the input member to the output member.

Cam faces 24a and 24b are continuously formed in a circle on upper and lower faces which are perpendicular to an axial direction of a rotatable cam 24 which constitutes a rotational drive mechanism 21. Elastic members 23b are formed integrally with a holder member 23 for rotatably supporting the rotatable cam 24 to extend in the axial direction, and the first fixed cam and second fixed cam 23c and 23d having a small number of cam faces at butts and tips of the elastic members are arranged to face each other via the upper and lower cam faces 24a and 24b of the rotatable cam 24. The rotatable cam 24 is retreated and moved forward in the axial direction by writing pressure applied to a writing lead to be rotationally driven in one direction and rotational motion of the rotatable cam 24 is transmitted to the writing lead.

Cam faces 24a and 24b are continuously formed in a circle on upper and lower faces which are perpendicular to an axial direction of a rotatable cam 24 which constitutes a rotational drive mechanism 21. Elastic members 23b are formed integrally with a holder member 23 for rotatably supporting the rotatable cam 24 to extend in the axial direction, and the first fixed cam and second fixed cam 23c and 23d having a small number of cam faces at butts and tips of the elastic members are arranged to face each other via the upper and lower cam faces 24a and 24b of the rotatable cam 24. The rotatable cam 24 is retreated and moved forward in the axial direction by writing pressure applied to a writing lead to be rotationally driven in one direction and rotational motion of the rotatable cam 24 is transmitted to the writing lead.

The present invention is a chuck body (13) provided with: a hollow, substantially cylindrical fastener (11) having a tapered inner surface (13) in which the diameter of the hole gradually changes along the axial direction; and a chuck (21) having a divided end part (23) divided into two or three, the divided end part (23) having a tapered outer surface (24) that can enter or exit from the fastener (11) and that comes into contact with the tapered inner surface (13) of the fastener (11) when entering the fastener (11). When the divided end part (23) of the chuck (21) closes in the fastener (11) and holds the core (10), the angle of the tapered outer surface (24) of the chuck (21) relative to the center axis line of the chuck (21) is substantially identical to the angle of the tapered inner surface (13) of the fastener (11).

The present invention is a chuck body (13) provided with: a hollow, substantially cylindrical fastener (11) having a tapered inner surface (13) in which the diameter of the hole gradually changes along the axial direction; and a chuck (21) having a divided end part (23) divided into two or three, the divided end part (23) having a tapered outer surface (24) that can enter or exit from the fastener (11) and that comes into contact with the tapered inner surface (13) of the fastener (11) when entering the fastener (11). When the divided end part (23) of the chuck (21) closes in the fastener (11) and holds the core (10), the angle of the tapered outer surface (24) of the chuck (21) relative to the center axis line of the chuck (21) is substantially identical to the angle of the tapered inner surface (13) of the fastener (11).

Provided is a writing instrument or an applicator using resin parts formed, by way of two-color molding, to have an optimal guiding clearance between slide members. A plurality of resin molded parts is included. At least one of the plurality of resin molded parts is formed as a primary molding, and at least another one of the resin molded parts is formed as a secondary molding, by way of two-color molding, using a portion of a surface of the primary molding. The primary molding and the secondary molding are separated to be used as independent members. In this case, the primary molding and the secondary molding are preferably configured to slide against each other by each separating portion.

Provided is a writing instrument or an applicator using resin parts formed, by way of two-color molding, to have an optimal guiding clearance between slide members. A plurality of resin molded parts is included. At least one of the plurality of resin molded parts is formed as a primary molding, and at least another one of the resin molded parts is formed as a secondary molding, by way of two-color molding, using a portion of a surface of the primary molding. The primary molding and the secondary molding are separated to be used as independent members. In this case, the primary molding and the secondary molding are preferably configured to slide against each other by each separating portion.

To protect a writing core, a writing utensil includes: a shaft tube; a holder which is inserted through a front opening of a shaft tube and protrudes forward from a front end of the shaft tube; a writing core which is inserted through the holder while coming into contact with an inner peripheral surface of the holder and is supported by the shaft tube so as to protrude forward from a front end of the holder; and a movement direction conversion mechanism which is provided between the shaft tube and the holder and moves the holder forward relative to the shaft tube and the writing core by a force applied to the holder in the shaft tube outward radial direction.

To protect a writing core, a writing utensil includes: a shaft tube; a holder which is inserted through a front opening of a shaft tube and protrudes forward from a front end of the shaft tube; a writing core which is inserted through the holder while coming into contact with an inner peripheral surface of the holder and is supported by the shaft tube so as to protrude forward from a front end of the holder; and a movement direction conversion mechanism which is provided between the shaft tube and the holder and moves the holder forward relative to the shaft tube and the writing core by a force applied to the holder in the shaft tube outward radial direction.