Coating implements with material supply – Bifurcate pointed nib tool – Including reservoir and feeder
Reexamination Certificate
2002-11-27
2003-11-25
Nguyen, Tuan N. (Department: 3751)
Coating implements with material supply
Bifurcate pointed nib tool
Including reservoir and feeder
C401S221000, C401S224000, C401S231000, C401S235000, C401S265000, C401S292000
Reexamination Certificate
active
06652177
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a nib for use with fountain pens and other writing instruments and to a method of manufacturing the same. The present invention also relates to a composite conical nib made from a ceramic material with excellent durability.
2. Description of Prior Art
Writing instruments such as fountain pens have conventionally been using nibs with high durability. In the case of a fountain pen, a nib is tipped with a wear-resistant alloy by fusing, formed with a slit and polished at corners to round a tip of the nib. As an example of such a conventional nib, a conical nib is shown in FIG.
1
. In
FIG. 1
reference numeral
100
represents a nib comprising a nib base body
200
molded of a resin and having a predetermined thickness and a converging member
300
.
The nib base body
200
is integrally molded of a synthetic resin material by injection molding and, as shown in
FIG. 2
, has a cylindrical base portion
201
and a plurality of combtooth pieces
202
protruding from one end of the base portion
201
. These combtooth pieces
202
are arranged along a circumference, centered at a center axis of the nib, at equal intervals with a slit
203
formed therebetween. The base portion
201
has a large-diameter portion
211
and a small-diameter portion
212
with a stepped portion
213
formed at a boundary between them. The combtooth pieces
202
, each shaped like an arc in cross section, protrude continuously from one end of the large-diameter portion
211
of the base portion
201
and progressively taper off toward the front end. A base portion-side half of each combtooth piece
202
extends almost linearly along an outer circumferential surface of the large-diameter portion
211
and a front end-side half tilts inwardly so that the combtooth pieces
202
progressively approach the center axis toward the front end. The combtooth pieces
202
as a whole are brought closer together inwardly by urging them from their outer circumference toward the center axis. That is, the base end side halves are combined together in a virtually cylindrical shape and the front end side halves in a virtually conical shape. The combtooth pieces
202
have hemisphere-divided portions
204
at their front ends which, when brought together, form a hemisphere. The hemisphere-divided portions
204
are rounded at their outer corners.
The converging member
300
, as shown in
FIG. 1
, is formed into a cylinder that can be fitted over an intermediate portion of the nib base body
200
. The converging member
300
has an inner circumferential structure adapted to press the combtooth pieces
202
toward the center axis to converge into a conical shape that progressively decreases in diameter toward the front end.
The nib
100
has the nib base body
200
and the converging member
300
of the above construction as constitutional elements. The converging member
300
is sleeved over the nib base body
200
from its front end and snugly fitted over the circumference of the nib base body
200
, so that the inner circumferential structure of the converging member
300
presses the combtooth pieces
202
from outside toward the center axis. Under a uniform pressure of the converging member, the base end side halves converge into an almost cylindrical geometry without distortion and the front end side halves also converge into an almost conical geometry without distortion whose diameter progressively decreases toward the front end. As a result, the adjoining combtooth pieces
202
engage with each other, bringing together the hemisphere divided portions
204
at their front ends to form a smooth hemisphere writing tip
400
with no undulations. In this condition, ink feeding paths
500
, capillary-like gaps, are formed between side interfacing portions of the combtooth pieces
202
.
In the nib
100
constructed as described above, when the semispherical writing tip
400
is pressed against a surface of writing paper with the pen axis at an angle, the hemisphere divided portions
204
at the free ends of the combtooth pieces
202
slip relative to each other and elastically deform to enlarge an outer diameter of the hemisphere portion at the tip. When the pressing force is removed, the tip of the nib restores its original shape by its elasticity. This behavior allows the nib to write on a paper surface in any direction and, even if the nib is rotated about the pen axis, to write at any position on the hemispherical tip portion and at any angle. Further, the thickness of a line can be changed by adjusting a writing pressure, permitting the writer to write a variety of modes of letters with a changing line width, such as those produced by a writing brush.
The conventional conical nibs, however, have the following problems.
(1) Since the nib base body is molded in the form of a set of combtooth pieces that together have a conical shape, it has a complex geometry, making molding dies complex and expensive and rendering a mass production impossible.
(2) Since the nib base body is molded in the form of a set of combtooth pieces that together have a conical shape, a check to see whether each of the combtooth pieces has a predetermined dimensional accuracy can only be made after the combtooth pieces are assembled into a final product as by fitting a ring over them.
(3) To give a smooth writing feel requires rounding outer surface corners of the tip portion. The outer surface corners are rounded as by a barrel polisher. During this process, the combtooth pieces interfere with each other at slit portions, making it necessary to check that the rounding is being carried out as desired in the middle of the process. This degrades an efficiency of the chamfering or rounding work.
(4) To make the nib of the pen a final product after the rounding operation requires fitting a ring (converging member) over the nib front end portions divided like combteeth. An attempt to perform this ring fitting operation by using an automated assembly machine results in the combtoothlike molded pieces of the nib base body interfering with each other at slit portions and the nib base body failing to rest in its place on an automated feeding apparatus such as a parts feeder. The ring fitting operation must therefore be done manually.
Of the conventional nibs described above, ceramic nibs are drawing attention as highly wear-resistant nibs. Examples of ceramic nibs are disclosed in Japanese Utility Model Disclosure Nos. 60-8085, 60-109979 and 1-86578, and Japanese Patent Disclosure No. 1-146797. Some of the proposed ceramic nibs of this kind have a construction in which a nib body of ceramic plate is formed with a slit and has its tip rounded or in which a barlike nib body is formed with a longitudinal through-hole as an ink feeding hole to supply ink to the tip.
The conventional ceramic nibs, however, has the following drawbacks. Although the ceramic nib has a groove or through-hole for feeding ink, since it is hard and cannot deflect as can a platelike stamped metal nib, the groove or through-hole cannot deal with a change in ink viscosity or with ink scum, resulting in an interruption of ink feed. Further, fine dirt and paper dust produced by contacts between the writing tip of the nib and a paper surface may clog an ink path in the nib body. If that happens, since the nib has almost no provisions for cleaning, the writing performance inevitably becomes unstable. These problems are a major reason that the ceramic nibs, though they use a wear-resistant material, have not been put to practical use and that pens using a ceramic nib have not been able to be marketed as practical writing instruments.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a conical nib having a plurality of independent combtooth pieces which can converge progressively toward the front ends thereof and combine to form a virtually conical shape over the entire length and a virtually spherical shape at the front ends. These combtooth pieces are each shaped li
Shimada Nobuhiko
Yamanaka Shizuo
Haynes and Boones, LLP.
Nguyen Tuan N.
Yamanaka Kazue
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