Writing tool

Details Writing tool Writing tool

1997-03-05

2000-03-28

Walczak, David J.

Coating implements with material supply

Including ball, roller or endless-belt tool

Ball

401209, B43K 710

Patent

active

060422904

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The present invention relates to a writing tool, and particularly to a tip of the writing tool having a valve construction designed such that a rotary body, mounted in a ball house within the extreme end of a tip connected to the extreme end of a liquid tank filled with ink or an applying liquid, is urged forward by a coiled spring inserted and present within the tip, into contact with an inwardly directed extreme end edge of the tip so that the ink or the applying ink does not leak. When in use, the rotary body, a part of which is projected from the extreme end of the tip, is pressed against a paper surface to retreat into the rotary body against the force of the coiled spring, whereby the ink or the applying liquid is transferred onto a paper.


DESCRIPTION OF THE PRIOR ART

The tip of the writing tool of this kind has been generally known so for in the construction exemplified in FIG. 20 (as disclosed in Japanese Utility Model Laid-Open No. Hei 6-11873).
A tip 30 of the conventional writing tool is designed such that a rotary body 32 is mounted in a ball house 31 within an extreme end thereof. A washer 33 is provided at the rear end of the tip 30. A coiled spring 34 having substantially the same length as that of the tip 30 is inserted and provided between the washer 33 and the rotary body 32, whereby the rotary body 32 is urged into contact with an inwardly directed extreme end edge 31-1 of the ball house 31. An applying ink within a liquid tank 35 therefore does not flow out of a liquid applying port 36 of the ball house 31. That is, the rotary body 32 and the inwardly directed extreme end edge 31-1 of the ball house 31 form a closed valve.
The tip used in the writing tool of this kind is formed from a relatively small diameter metallic pipe. Accordingly, the coiled spring 34 must also have a smaller diameter. A high degree of processing technology and incorporating technology with high precision is required, with a resultant high processing cost. That is, coiled spring 34 must be manufactured about the same length as that of the tip using a high degree of processing technology increasing the processing cost for the coiled spring.
Further, since the coiled spring 34 extends the full length of the tip, the coiled spring 34 forms an obstacle which impedes the flow of liquid from liquid tank 35 to ball house 31 through the tip 30.
Furthermore, to incorporate coiled spring 34 into the tip 30, the coiled spring 34 must be arranged to apply suitable (spring) force against washer 33. This makes it difficult to concentrically arrange the coiled spring 34 within the tip 30. That is, in the absence of a support for the coiled spring 34 which centers it relative to the core of the tip 30, the washer 35 is pressed into the rear end of the tip 30 to incorporate and arrange the coiled spring 34 in the tip 30. This makes it difficult to center the tip 30 relative to the core. Therefore, the coiled spring 34 may deviate when incorporated into the tip 30. Although the coiled spring 34 should be properly inserted into the tip 30 in the centered state, since the coiled spring 34 is not supported, the deviation would occur during use for a short period of time. During any such deviation, the force applied to rotary body 32 may not be balanced, making it difficult to evenly place the rotary body 32 in contact with the inwardly-directed extreme end edge 31-1 of the ball house 31. That is, the valve constituted by the rotary body 32 and the inwardly-directed extreme end edge 31-1 of the ball house 31 may not be properly closed, such that the applying liquid may leak out.
Further, when the writing tool of this kind is put on a pen stand or the like with the tip directed upward, the applying liquid within the tip returns to the liquid tank due to gravity. If the applying liquid within the tip does not quickly return to the liquid tank, the applying liquid remaining in the tip solidifies over time, which may impede expansion and contraction of the coiled spring. In other words, the valve cannot open and

REFERENCES:
patent: 2107424 (1938-02-01), Platt
patent: 2930062 (1960-03-01), Reimann
patent: 3819285 (1974-06-01), Andrews et al.
patent: 3902815 (1975-09-01), Williams
A copy of a PCT Search Report issued in PCT/JP 96/01903.

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