Patent ID: 7588383
Filing Date: 2009-09-15
Classification: B43K

Abstract:
1. A mechanical pencil, comprising: a main body of a tubular shape and having a length direction and a distal end and a proximal end in the length direction; an advancing mechanism arranged within the main body; and a slider arranged within the main body, wherein the advancing mechanism comprises a chuck adapted to hold a lead, a collar for fastening the chuck and disposed outside of the chuck, and a biasing member for biasing the chuck toward the proximal end, the chuck being movable in the length direction by a knocking operation in such a manner as being moved forward to an advanced position by an external operation and moved backward to a retracted position by means of the biasing member on condition that the external operation is released with the chuck at the advanced position, the chuck being engaged with the collar so as to hold the lead on condition of being at the retracted position, and being disengaged from the collar so as to release the lead on condition of being at the advanced position, wherein the slider, comprising a lead guide and a lead friction member, is positioned at a distal side of the chuck so as to be movable in the length direction, the lead friction member being made of thermoplastic elastomer, and wherein the knocking operation renders the chuck to be advanced holding the lead so as to extend the lead to a predetermined position, to release the lead at the position, and to be retracted with maintaining the position of the lead by friction between the lead and the lead friction member, consequently advancing the lead to a distal end of the lead guide, wherein the slider is adapted to move in the length direction maintaining contact with the main body and has an outer friction part in contact with the main body and an inner friction part to be in contact with a lead, the inner friction part being formed on the lead friction member, and the inner and outer friction parts each having a frictional resistance so that the frictional resistance of the inner friction part is smaller than that of the outer friction part.