JPS6241827Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is intended to improve the problem of dust clogging during writing in a writing instrument whose pen tip is a pipe and a rod slidably inserted into the pipe.

2. Description of the Related Art Conventionally, various writing instruments are known in which ink is drawn out by pressing a rod slidably inserted into a pipe against a paper surface and compressing an elastic body behind the rod. Utility Model No. 52 related to the applicant's invention
Japanese Patent No. 136736 also discloses a capillary type writing instrument in which a porous foam is fixed in a barrel and an ink guiding core is loosely inserted so as to be retractable. In such writing instruments, if the elastic force of the elastic body is high, the rod will not only wear out quickly, but also have the problem that the rod will get stuck on the paper surface when writing, resulting in poor writing quality. It is desirable that the elastic force of is low.

On the other hand, reducing the elastic force causes a problem in that it becomes difficult to remove dust that has entered the pipe during writing. That is, paper pulp and other debris can clog the pipe, preventing the rod from returning to its original position and preventing ink from flowing out.

Therefore, what is required of the elastic body is that its elastic force is low at least while the amount of deformation is small, and that its elastic force becomes considerably high as the amount of deformation increases.

One method of satisfying the above requirements is to use a thin piece of elastic material with low elasticity. By using a thin piece, the relative deformation rate with respect to the amount of displacement of the rod can be increased, and the change in elastic force can be increased.
However, even with this method, since Γ is thin, there is a high probability that it will be deformed during installation or that the installation direction will be incorrect.

Γ Even if it is installed in the normal position, since a perfectly elastic body does not exist, a certain amount of plastic deformation will occur over time, but the amount of plastic deformation will be large enough to be evaluated against the wall thickness, and the initially set elasticity will be It becomes something far removed from power.

Γ It is difficult to precisely control wall thickness even when using members that do not easily undergo plastic deformation.

This leaves me with the same problem.

Based on the above, the present inventors believe that although it is not a completely elastic body, [the elastic force of an elastic body,
In other words, as long as an elastic body is used that practically satisfies the following: force imparting sliding properties to the rod = [constant coefficient] We concluded that the problem could not be improved and came up with the present study. That is, the gist of the present invention is to use a pipe and a rod slidably inserted into the pipe as a pen tip, A writing instrument in which sliding properties are imparted to the rod using an elastic body,
The writing instrument is characterized in that the elastic body has an irregular shape in its longitudinal section that increases the increase in the force imparting sliding properties per unit sliding distance when the sliding distance of the rod increases. It is something.

Here, it will be understood that the "longitudinal section" means the sliding direction of the rod, but the point of the present invention is that the above-mentioned [constant coefficient] , a coefficient having a large value], it will be understood based on the explanation of the following embodiments that the above-mentioned problem has been improved.

Hereinafter, an embodiment of the present invention will be described based on the attached drawings. FIG. 1 shows the state when not writing, and the rear end of the rod 2 slidably inserted into the pipe 1 has a relay. The core 5 prevents backward movement,
An elastic body 3 whose longitudinal section is H-shaped is arranged. Although not shown, the rear of the relay core 5 continues to the ink chamber. Incidentally, reference numeral 4 is a chip holder.

The pipe 1 can be made of various materials, but in order to prevent abrasion due to contact with paper surfaces, etc., it is best to use materials with excellent wear resistance such as stainless steel, ceramic, and ruby. It is usually made of synthetic resin, metal, etc. and has holes or grooves for ink circulation, but it is not necessary to form them. Further, in order to maintain good contact with the elastic body 3 made of urethane foam, synthetic rubber, nonwoven fabric, sponge, etc. at the rear end of the rod 2, it is preferable that a bulge 2a be formed. There is no need for an agent or a fixing member, and it is possible to prevent immersion into the elastic body 3.

In the writing instrument shown in FIG. 1, when the rod 2 is displaced backward in response to use, the reduced portion 3a substantially bears the elastic force of the elastic body 3 in the initial stage, as shown in FIG. . However, as shown in FIG. 3, when dirt on the paper enters into the pipe 1, the reduced portion 3a is crushed by the expanded diameter portions 3b ₁ and 3b ₂ , and the elastic force of the elastic body 3 is suddenly reduced. becomes higher. Therefore, the repulsive force that the rod 2 receives also increases,
It acts on the discharge of garbage 6.

Various shapes of the elastic body 3 can be considered. For example, the longitudinal section may be circular as shown in FIG. 4, three expanded diameter portions 35b connected by a reduced portion 35a as shown in FIG. 5, or a simple convex shape as shown in FIG. For example, it may have a trapezoidal shape as shown in FIG. 7. If you do not like sudden changes in elastic force (sudden changes when transitioning from FIG. 2 to FIG. 3), it is better to have a gentle connection from the constricted portion to the expanded diameter portion. A representative example thereof is a sphere or cylinder whose vertical cross section is circular, as shown in FIG. In particular, when a sphere is used as an elastic body, the contact with the rod becomes point-like, and the contact area can be expanded as the rod moves backward, so the pressure exerted by the rod on the paper is extremely small in the initial writing, and gradually increases. can. Moreover, since the direction does not matter, it is extremely convenient for assembling the writing instrument.

Regarding the positional relationship between the rod and the elastic body, the elastic body does not necessarily have to be present at the rear end of the rod. FIG. 8 shows an example, in which a rod 2' having a bulging portion 2a' extends rearward at its rear end so as to pass through an elastic body 3'. In the case of a so-called raw ink type writing instrument using a bellows 7, the ink outflow can be promoted by the rod extending backward.

In this case, the rod and the elastic body can be used together to assemble a writing instrument.

In addition to the embodiments described above, other modifications may be made as appropriate without departing from the gist of the present invention.
As a minimum, it is important to keep in mind that in the case of an elastic body in which the connection from the constricted portion to the expanded diameter portion is not smooth, for example, the elastic body shown in FIGS. 1 and 6, the constricted portions 3a, 36a If the rod is too long (the length in the sliding direction of the rod), only the reduced diameter portion may substantially bear the elastic force of the elastic body even when the rod is clogged with dirt. If the elastic body 3 is in the state shown in FIG. 2 in FIG. 3, which shows the state at the time of dust intrusion, there will be no substantial difference from the case where the elastic body 3 is only the reduced portion 3a.

Therefore, the longitudinal cross-sectional deformity imparted to the elastic body may be appropriate, but it is limited only when the sliding distance of the rod becomes long, that is, when the rod slides until clogging with invading dirt becomes a problem. In some cases, it must be set within a range that increases the amount of increase in the force imparting sliding properties per unit sliding distance, that is, the value of the above-mentioned "coefficient."

And precisely because the present invention has been developed in this way, it is possible to reduce the contact force of the rod to the writing surface, and when dirt is clogged, it can be ejected out of the pen tip with a high elastic force, resulting in a good result. The writing quality makes it possible to use it for a long time.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIGS. 1 to 3 are longitudinal sectional views of main parts showing the deformation of the elastic body from the time of non-writing to the time of clogging with dust, and FIGS. 4 to 7. 8 is a longitudinal sectional view showing another embodiment of the elastic body, and FIG. 8 is a longitudinal sectional view of a main part showing another embodiment of the present invention. 1... Pipe, 2, 2'... Rod, 2a, 2
a'... Rod bulge, 3, 3'... Elastic body, 3a,
34a, 35a, 36a, 37a...Elastic body reduction part, 3b ₁ , 3b ₂ , 34b, 35b, 36b, 37
b...Elastic body expanded diameter part.

Claims (1)

[Scope of utility model registration request] In a writing instrument in which the pen tip is a pipe and a rod slidably inserted into the pipe, and an elastic body is used to impart sliding properties to the rod, when the sliding distance of the rod becomes longer, A writing instrument characterized in that the elastic body has an irregular shape in a longitudinal section that increases an increase in sliding force imparted per unit sliding distance.