Mitsubishi Pencil Company, Limited

Yoshitoshi Osano

Kyo Nakayama

Takeo Fukumoto

Hirotake Izawa

Norio Ohsawa

Takeshi Kobayashi

A writing lead () is grasped and released by reciprocation of a chuck () provided in a body cylinder () so as to inch the writing lead forward and a rotational drive mechanism is provided for rotationally driving a rotor () in one direction in conjunction with retreat operation by the writing pressure applied to the writing lead and forward movement by releasing the writing pressure. A pipe support member () for supporting a pipe end () is accommodated in a base (A) which constitutes a front end portion of the body cylinder, and a retreat drive mechanism is provided for gradually retreating the pipe support member into the body cylinder in conjunction with rotational drive operation of the rotor. With the above-mentioned structure, a pipe-slide type mechanical pencil can maintain an amount of projection of the writing lead from the pipe end within a certain range.

Mechanical pencil

A chuck unit () for grasping a writing lead () and a rotor () arranged to be movable in a direction of rotation and an axial direction within a body cylinder () are provided. First and second cam faces () and () are respectively formed at one end face and another end face of the rotor in the axial direction, and first and second fixed cam faces () and () are arranged on the body cylinder side to face the first and second cam faces respectively. The first cam face in the rotor is brought into abutment with and meshed with the first fixed cam face by retreat operation of the chuck unit under writing pressure, and the second cam face in the rotor is brought into abutment with and meshed with the second fixed cam face by releasing the writing pressure, so that the rotor rotates, whereby the writing lead also rotates.

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Yokohama, Japan

Yoshitoshi Osano