US Patent 7641412 Ball-point pen

A ball-point pen, wherein a cover member (6) is fitted to a joint member (3) connecting a writing tip (1) rotatably supporting a writing ball (2) at the tip thereof to an ink storage tube. When the cover member (6) is fitted to the joint member (3) along the outer peripheral surface thereof, a part of the cover member does not come within 0.2 mm (within the range of the chain double-dashed line) from around the writing tip. Thus, even if the accuracies of parts and assembly machines are dispersed, a problem with an existing ball-point pen wherein a cover member is brought into contact with a writing tip and the writing tip is damaged in an assembly step can be avoided.