Ball-point pen with back flow stop

Details Ball-point pen with back flow stop Ball-point pen with back flow stop

1995-08-04

1998-01-27

Muir, D. Neal

Coating implements with material supply

Including ball, roller or endless-belt tool

With flow-regulator

401214, B43M 1102

Patent

active

057116261

DESCRIPTION:

BRIEF SUMMARY
SPECIFICATION

1. Technical Field
The present invention relates to a ball-point pen. The invention, in particular, relates to a ball-point pen equipped with a back leakage preventing machanism for preventing a so-called back leakage phenomenon that, when a ball-pen is used to write with its tip up, air-bubbles enter the refill through channels between a ball and its holder thereby causing ink to flow toward the backside of the ball.
2. Background Art
A ball-point pen holds, at its front end, a small ball which receives frictional forces as writing and rotates on paper, to thereby draw ink out of a tube and transfer it onto the sheet.
As shown in FIG. 39, a structure `a` of a writting portion in a ball-point pen is generally composed of a ball `b` and a holder `d` rotatably holding the ball `b` on a socket seat `c`. This assembly made of the ball `b` and the holder `d` is called a tip `e`. The tip `e` is connected with an unillustrated refill as an ink reservoir, so that ink is supplied to the ball `b`.
Meanwhile, the ball-point pen accidentally becomes incapable of writing even with sufficient ink remaining in the refill. This can be attributed to the following cause: surfaces inside the tip `e` are corroded whereby the rotation of the ball `b` is disturbed. This is liable to happen when the pen has been left unused for a prolonged period of time. worn out and deformed so as to disturb smooth rolling of the ball `b`, or excessive use deforms a hold `g` at the front end of the ball socket seat in the holder `d` thereby inhibiting the rotation of the ball `b`. `h` between the holder `d` and the ball `b` has been left for a prolonged period of time, these dust and dirt induce ink to dry and stick to the ball `b` and the holder `d`, whereby the rotation of the ball `b` is disturbed. refill and air enters the gap. In this case, the ball `b` itself can rotate, unlike the aforementioned cases 1) to 3) in which ink cannot come out due to the obstruction to the rotation of the ball `b`. Nevertheless, because the ball `b` is not in contact with ink, the ball `b` rotates in vain and cannot bring the ink which is in the refill to the paper surface. Such an idle rotation is liable to occur when the pen is used to write with its tip up. In this case, when the ball `b` uses up the ink therearound, the ink in the refill does not follow the rolling of the ball `b`, whereby a gap is created between the ball `b` and the ink. Accordingly, however does the ball `b` rotate, the ink in the refill will not come out. To make matters worse, when upward writing is done, air enters the refill through the clearance `h` between the ball `b` and the holder `d` and the ink flows toward the opposite direction to the ball `b`, causing a back leakage.
A main object of the present invention is to provide a ball-point pen cap able of preventing the back leakage which is liable to occur when upward writing is done.
Other objects of the present invention will be apparent from a reading of the following detailed description with reference to the accompanying drawings.


DISCLOSURE OF THE INVENTION

1. A ball-point pen has a ball-point pen refill which comprises: a tip rotatably holding a writing micro-ball fitted by press-forming at a front end thereof; an ink storing pipe storing ink; and is constructed such that a joint connecting the tip with the ink storing pipe, the joint is formed with a tip-side bore and an ink-storing-pipe-side bore for allowing ink to pass therethrough when the tip and the ink storing pipe are fitted into the joint; the tip-side bore and ink-storing-pipe-side bore are communicated by a communicating hole which is composed of a large-diameter portion and a small-diameter portion connected to the tip-side bore and the ink-storing-pipe-side bore, respectively; and a large ball having a greater diameter than a bore diameter of the small-diameter portion is disposed freely movably in at least a part of a space formed between the rear end of the tip and the large diameter portion when the tip is fitted into the tip-side bore.

REFERENCES:
patent: 1563408 (1925-12-01), Sutherland
patent: 2719314 (1955-10-01), Taube
patent: 2999266 (1961-09-01), Rosenthal
patent: 3074380 (1963-01-01), Polishuk
patent: 4063829 (1977-12-01), LaMura
patent: 4573820 (1986-03-01), Kirchhoff
patent: 5279499 (1994-01-01), Carter

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