Writing Instruments

Abstract

This invention provides writing instruments such as felt pens, marking pens or sign pens in which the construction is reinforced to strengthen the effect of writing instrument thereby increasing writing practice without causing deformation due to pressure applied to the pen point.

Description

This invention relates generally to the writing instruments, and more particularly to such writing instrument of the type comprising a core structure made of a wearproof and inkproof material and consisting of a plurality of vane plates arranged to form a stellate configuration in sectional shape and extending along the length of the instrument, subcore elements each having a capillary structure and each being positioned between each adjoining vane plates such as to form a small space therebetween, and a synthetic resin coating covering the entire outer periphery of the core and subcore assembly such as to form a sheath, with the end of said sheath being machined to form a pen point.

In other terms, the present invention relates to the improvements in the writing instruments such as felt pens, marking pens, sign pens or the like whereby desired writing practice can be performed by self-feeding the ink contained in the pen stem by utilizing the capillary action of the pen structure.

Heretofore, the writing instruments of this type have been mostly composed of a solidified assembly of a plurality of longitudinally disposed single fibers which were bundled and solidified into a penlike structure, or of a felt-made assembly also shaped into a penlike structure, with one end of said structure being formed like a pen point. However, these conventional articles are so poor in wear resistance that the pen point or nib portion is subject to early wear and is undesirably broadened during use. Also, due to such wear, the capillary structure tends to be partly blocked to deteriorate passage of ink.

It is therefore an object of the present invention to provide an improved writing instrument which is free of the above-said defects and which can be manufactured on a mass-production scale with ease.

Another object of the present invention is to provide an improved writing instrument of the type just described, in which the subcore elements each having a capillary structure are mounted between the vane plates of said core structure such as to define small spaces between said core structure and subcore elements, thereby to provide reinforcing effect to strengthen the writing instrument and to allow proper and desired writing practice without causing deformation due to pressure applied to the pen point during writing practice.

It is still another object of the present invention to provide an improved writing instrument of which the nib or writing portion, owing to the above-described construction, is highly resistive to wear and is not broadened even if it is used for a long time, and which also has no possibility that the capillary structure is partly blocked to deteriorate passage of ink.

Now, the invention will be described in detail by way of its preferred embodiment with reference to the accompanying drawings, in which:

FIG. 1 is a partially cutaway perspective view of the writing instrument according to the present invention;

FIG. 2 is a cross-sectional view as taken on the line II--II of FIG. 1; and

FIG. 3 is a fragmental perspective view of a blank article according to the present invention.

Referring generally to the drawings, reference number 1 denotes the vane plates of the core structure 2, said vane plates being arranged radially as shown and made of a wearproof and ink-resistant material such as polyacetal resin, polyamide resin or light metals. Reference number 3 designates the capillaries (for example 0.1 mm. wide) provided at the center of the subcore elements 4 made of polyacetal resin or other similar material. It is to be noted that each said subcore element 4 is disposed between each adjoining vane plates 1 in such a manner as to form therebetween a small space 5 (for example 0.05 mm. wide). Enclosing the outer periphery of the vane plate and subcore assembly is a sheath structure 6 made of easily meltable synthetic resin such as polypropylene resin or polyethylene resin, with one end of said sheath 6 being formed like a pen point. Designated by reference number 8 in the drawings is a small hole which is formed in the center of the core structure 2 along the full length thereof when the viscosity of inks is high. In said hole 8 is stuffed a sheaf of fibers such as acrylic filaments (said sheaf having a size of several of for example 3 denier).

In use of the present device having the above-described construction, the sheathed structure is inserted rear-endwise into a pen holder through an end opening in the head portion thereof until the rear end of the sheath 6 reaches the ink source in the holder, whereby ink will be allowed to flow through the small spaces 5 between the vane plates 1 and the subcore elements 4 and through the capillaries 3 to the nib or writing portion 7 at the front end of the structure. Since the writing portion 7 is constantly supplied with a suitable amount of ink, it is possible to conduct the smooth and desired writing practice in the same manner as the conventional writing pens.

According to the present invention, additional strengthening effect is provided by the subcore elements 4 which are securely fitted between the vane plates 1 in a bracelike manner, so that smooth and proper writing practice can be performed even for a long time without causing any undesirable deformation of the nib portion 7 due to pressure applied thereto during the writing practice. Also, there is no fear that the nib portion 7 is worn and broadened, or that the capillary structure is partly blocked to deteriorate passage of ink.

AN EXAMPLE:

With particular reference to FIG. 3, a plurality of small tubular elements 4' each made of polyacetal resin and each having formed in its center a small axial hole 3' of about 0.1 mm. in diameter are mounted around an about 50 meter-long core structure 2 made of polyacetal resin such that each said tubular element 4' is disposed between each adjoining vane plates 1 of said core structure, to thereby prepare a blank article as shown. Then, a compressing pressure (about 120.degree. C., 50 kg/cm.sup.2) is applied uniformly on the circumferential periphery of said article to press said small tubular elements 4', whereby said small holes 3' will be flattened to constitute the capillaries 3, and thereby the sub-core elements 4 are formed. Thereafter, a coating of synthetic resin such as polypropylene resin is applied entirely or partly on the outer peripheral surface of the prepared structure to form a sheath 6. Then the structure is cut into segments of a desired length (for example 3 cm.), and one end of each said segment is lathed by a grinder or other suitable cutting means to form a nib portion 7, thereby completing an article of the present invention.

Claims

What I claim:

1. A writing instrument comprising a core structure made of a wearproof and ink resistant material and consisting of a plurality of vane plates arranged to form a stellate configuration in sectional shape and extending along the length of the structure, subcore elements each having a capillary structure and each being positioned between each adjoining vane plates such as to define a small space therebetween, and a synthetic resin coating covering the entire outer periphery of the core and subcore assembly such as to form a sheath, with the end of said sheath being machined to form a pen point.

2. A writing instrument according to claim 1, in which said wearproof and ink-resistant material constituting said core structure is polyacetal resin, polyamide resin or light metal.

3. A writing instrument according to claim 1, in which said each subcore element is made of polyacetal resin.

4. A writing instrument according to claim 1, in which said sheath is made of polypropylene resin or polyethylene resin.