Metal tip for ball-point pen
AssigneeMitsubishi Pencil Company, Limited
InventorsShinsuke Sato, Toshiaki Takayanagi, Toru Kitao, Masao Hashi
Life of this patent
Estimating the term…
Abstract
This invention provides a metal tip for a ball-point pen, having an ink guide hole (2) formed at the center of the bottom surface of a ball holding portion (1) and radial grooves (3) arranged around the ink guide hole. The ink guide hole has a diameter 30 to 55% the diameter of a ball and a length 1.2 to 2 times the diameter of the ink guide hole. A cleaning tool, used for removing a flash which is formed during formation of the radial grooves (3) by cutting (broaching) and which projects into the ink guide hole (2), is set to have a diameter 70 to 97% the diameter of the ink guide hole, so that only a base portion of the projecting flash is left.
Claims4
A tip for a hall-point pen with a ball having a diameter set therein, said tip comprising:
- a ball holding portion within which the ball is positioned;
- an ink guide hole, said ink guide hole having a diameter and being formed at a center of a bottom surface of said ball holding portion, a portion of the ball extending into said ink guide hole;
- radial grooves arranged around said ink guide hole, each said groove angularly oriented with respect to said ink guide hole;
- a flash oriented into said ink guide hole and projecting along 1.5% to 15% of said diameter of said ink guide hole;
- and
- a back hole formed behind said ink guide hole;
- wherein said ink guide hole diameter is 30% to 55% of the diameter of the ball and said guide hole has an axial length of 1.2 to 2 times said ink guide hole diameter.
Dependencies are inferred from the claim text.