DEVICE FOR ADVANCING A LEAD IN A MECHANICAL PENCIL

A lead projecting device of a mechanical pencil is provided to adjust the length of a lead finely by rotating a rail guide cylinder positioned at the outer side of a mechanical pencil body with a finger. In a mechanical pencil, a body(10) is composed of a main body(11) containing leads and an auxiliary body(12) vertically extended at the end of the main body, wherein a diameter of the auxiliary body is smaller than an upper body. A rotary guide cylinder(3) is rotatably installed at the outer peripheral surface of the auxiliary body. A cap(20) is combined with the end of the auxiliary body by spirals and provided with a lead hole(21). The auxiliary body has a perforated portion crossing the upper and lower ends. Two support rollers installed rotatably are mounted on the upper and lower parts of the perforated portion, respectively. A guide rail having helixes on the outer peripheral surface is installed at the support rollers arranged at the upper and lower parts. The rotary guide cylinder is engaged with the helixes of the guide rail by helixes formed on the inner peripheral surface. The rotary guide cylinder rotates forward and reversely to move the guide rail rectilinearly.