The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 21, 1997
Filed:
Feb. 14, 1996
Mitsubishi Pencil Kabushiki Kaisha, Tokyo, JP;
Abstract
A ball-point pen having a coupling, a tip at the distal end of the coupling, and a reservoir tube at the proximal end of the coupling. The tip may held in a tip holder, which, in turn, is coupled to the distal end of the coupling. A valve chamber is formed within the coupling with a ball seat having a guide hole therethrough on the rear portion of the valve chamber and projecting ridges on the front portion of the valve chamber. When the ball-point pen is positioned with its tip upward, a ball valve is brought into contact with the ball seat to close the guide hole and thereby prevent back flow of ink. When the ball-point pen is positioned with its tip downward, the guide hole is opened and the ball valve contacts the rear ends of the projecting ridges, so that ink flows into the tip through the guide hole, the valve chamber, and grooves formed between the ridges. A spring may be interposed in the inner hole of the tip with its proximal end held in place by the coupling. The distal end of the spring presses a writing point ball into contact with the ball-holding portion of the tip. A low-viscosity ink or an ink having shear thinning properties, i.e., statically a high viscosity which is decreased upon rotation of the ball during writing, is preferably used.