JPH0750234Y2 - Closed cap structure for small tube writing instruments - Google Patents

Description

[Detailed Description of the Invention] Detailed Configuration of the Invention [Industrial field of use] The present invention relates to a closed cap structure for a small tube type writing instrument having a small-diameter pen tip at the tip used for a plotter pen or a drawing pen. .

[Conventional technology]

Conventionally, as a cap structure for sealing a small tube type writing instrument,
First, the writing shaft is sealed with a cap, and the writing tip is inserted into the cap to press the pen tip of the small-tube writing instrument against the sealing member such as rubber contained in the cap to seal it. The structure prevents the ink in the tip from drying and closes the air holes provided in the small diameter pen tip. In addition, in order to mount the cap on the writing part shaft without lateral swing, the cap and the writing part shaft must be engaged with each other by a hermetically engaging part extending in the longitudinal direction.

[Problems to be solved by the device]

However, in the case of the above, when the cap is removed for writing, the seal member of the small-diameter pen tip first separates, and then the seal of the writing portion shaft is released. Moreover, at this time, the air in the cap is suddenly decompressed in order to disengage the appropriately extending engaging portion, and there is a risk that the ink in the small-diameter pen tip may flow out or the ink may flow out from the air hole of the tip shaft.

[Means for Solving the Problems]

The small-tube writing instrument of the present invention is configured such that the distance from the opening side edge of the sealing portion of the cap to the sealing surface in the sealing member is shorter than the distance from the outer step of the sealing portion of the writing portion to the tip of the small diameter nib. The lengthwise sealing distance between the sealing portion of the cap and the sealing portion of the writing portion is set to be shorter than the elastic deformation amount in the longitudinal direction of the sealing member pressed by the small-diameter pen tip. Furthermore, on either one of the inner surface of the cap and the outer surface of the writing part that are engaged with each other,
The engaging projection is formed at two positions appropriately separated in the longitudinal direction or extending appropriately in the longitudinal direction, and the engaging projection is completely divided in the longitudinal direction to form a groove.

[Action]

Therefore, when the cap is attached, the small-diameter pen tip is sealed by the sealing surface of the sealing member, and the air flow in the cap can be surely shut off by fitting the sealing portion of the cap and the sealing portion of the writing portion. When removing the cap, first, the fitting of the sealing part of the writing part and the sealing part of the inner surface of the cap comes off,
The cap comes off while air flows into the concave groove of the engaging projection. Then, the tip of the small-diameter pen tip is separated from the sealing surface of the seal member, after which the engagement between the cap and the writing portion is released, and the cap is completely separated.

〔Example〕

FIG. 1 and FIG. 2 show a first embodiment of the present invention. First, the structure of the writing part of a small tube type writing instrument will be described. The front shaft 2 is provided in front of the writing part shaft 1 storing ink. Press fit,
An air hole 2A for adjusting the internal pressure is formed in the front shaft 2. A holder 3 made of synthetic resin is press-fitted and attached to the tip of the tip shaft 2, and a small-diameter pen tip 4 made of a hard material such as ceramic is press-fitted and attached to the holder 3 to form a writing portion. Furthermore, a protective pipe 5 made of metal such as stainless steel for protecting the small diameter nib 4 is fitted on the outside of the small diameter nib 4. A joint 6 for adhering the ink in the ink storage chamber 1A to the small diameter nib 4 is fixed inside the tip shaft 2, and a core 7 is mounted in the small diameter nib 4. Next, the structure of the cap will be described. Inside the cap 8, a plurality of ribs 8A extending in the longitudinal direction are formed on the side surface of the deepest portion, and a sealing member 9 having elasticity such as rubber is fixed to the ribs 8A. On the inner surface of 8, a sealing portion 8B having the same diameter as the sealing portion 1B formed at the front portion of the writing portion shaft 1 is formed. Moreover, the distance L1 from the sealing surface 9A of the sealing member 9 shown in FIG. 3 to the edge 8C of the cap 8 on the opening side of the sealing portion is smaller than the tip 1C of the sealing portion of the writing portion shaft 1 shown in FIG. 4 is shorter than the distance L2 to the tip of the sealing member 8B, the sealing member 8B of the cap 8 and the sealing member 1B of the writing portion shaft 1 is sealed by the small-diameter pen tip 4 in the longitudinal sealing distance L3. 9 is set shorter than the elastic deformation amount L4 in the longitudinal direction.
In addition, the sealing part 8B of the cap 8 and the writing shaft 1
It is preferable that the longitudinal sealing distance L3 of the sealing portion 1B is as short as possible within a range capable of sealing the inside of the cap 8. The reason for this is the sealing distance
This is because the shorter L4 is, the less the pressure is reduced when the cap 8 is removed. Engagement protrusions 8E are formed on the inner surface of the cap 8 located closer to the opening 8D than the closed portion at two positions appropriately separated in the longitudinal direction, and the engagement protrusions 8E are completely divided in the longitudinal direction. A plurality of concave grooves 8F are formed. Although not shown, it is not always necessary to form a plurality of recessed grooves formed in the engaging projections, and even one recessed groove does not pose any problem.

When the cap 8 is attached to the writing portion shaft 1, the small diameter nib 4 is pressed against the sealing surface 9A of the sealing member 9 to seal the sealing surface 9A, and the sealing portion 1B of the writing portion shaft 1 is sealed to the sealing portion 8B of the cap 8.
Fit into each other to completely seal the inside of the cap 8
Prevents ink from drying more than 2A. Moreover, the cap 8 is engaged with the outer periphery of the writing portion shaft 1 by the engaging protrusions 8E at two appropriately spaced positions in the cap 8, and the cap 8 is securely fixed to the writing portion shaft 1 without lateral swing.

Next, when removing the cap 8 for writing, as described above, the longitudinal sealing distance L3 between the cap 8 and the writing portion shaft 1 is L3.
Is shorter than the elastic deformation amount L4 in the longitudinal direction of the seal member 9 which is pressed by the small-diameter pen tip 4, so that the sealed portion of the cap 8 is first removed only by slightly removing the writing portion shaft 1.
8B and the sealed portion 1B of the writing portion shaft 1 are disengaged. Then, the air flows through the concave groove 8F of the engaging projection 8E, and the air enters, and the atmospheric pressure in the cap 8 is immediately recovered by only slightly reducing the pressure.
Therefore, there is no possibility that ink will flow out from the air holes 2A.
Further, when the writing section shaft 1 is pulled out, the pen tip 4 having a smaller diameter than the seal member 9 is formed.
Are separated from each other, and then the writing shaft 1 is engaged with the engaging projection of the cap 8.
It comes off from 8E and the cap 8 is removed.

5 and 6 show a second embodiment of the present invention, in which engaging projections 11D are formed on the front outer surface of the writing section shaft 11 at two positions which are appropriately separated in the longitudinal direction, Further, a plurality of concave grooves 11E are formed to divide the engaging protrusion 11D in the longitudinal direction.
The inner surface 1 of the cap 18 is formed by the engaging protrusion 11D of the writing shaft 11.
8G is surely engaged.

The engaging projections formed on the inner surface of the cap or the outer surface of the writing portion axis are not limited to those formed at two positions extending in the longitudinal direction, and are not limited to those shown in FIGS. 7, 8 and 9. As shown, the engaging protrusion 21D formed on the writing portion shaft 21 may be formed by appropriately extending in the longitudinal direction. Of course, also in this case, the concave groove 21E that completely divides the engaging projection 21D in the longitudinal direction is formed. Moreover, as shown in the embodiment of FIG.
There is no problem even if the sealing positions of the sealing portion 21B of 21 and the sealing portion 28B of the cap 28 are located closer to the opening side of the cap 28 than the engaging position by the engaging protrusion 21D.

Further, although the above-mentioned embodiments are all described with the small tube type writing instrument having the core in the small-diameter pipe, the present invention is not limited to the above-mentioned embodiments, for example, as shown in FIG. The pen tip 14 does not have a core, or the pen tip (not shown) is formed with a plurality of holes for ink passages, and the tip shaft is directly provided with the small diameter pen tip. A writing instrument may be used, that is, a small-tube writing instrument having a small-diameter pen tip provided with a hole for guiding ink and an air hole formed in the tip shaft, and a cap that can be used for various small-tube writing instruments It is a structure.

[Effect of device]

As described above, according to the present invention, since the cap and the writing portion shaft are engaged with each other by the engaging protrusions at positions appropriately separated in the longitudinal direction, the cap can be mounted without lateral swing.

Furthermore, the feature of this invention is that when the writing shaft is removed from the cap,
Even if the distance between the engaging projections that is appropriately separated in the longitudinal direction is moved in the direction in which the writing portion axis is disengaged from the cap, the engaging projections are completely divided in the longitudinal direction by the concave groove, so the engaging projections There is no possibility that air will flow into the concave groove and reduce the pressure inside the cap. Therefore, there is no possibility that ink will flow out from the air holes of the small diameter pen tip.

Moreover, since the sealing of the tip of the small-diameter pen tip by the seal member is released after the cap and the seal portion of the writing portion shaft are released, there is no possibility that ink will flow out from the tip of the small-diameter pen tip.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a main part showing a sealing cap structure of a small tube type writing instrument of the present invention, FIG. 2 is a transverse sectional view taken along line AA of FIG. 1, and FIG. 1 is a longitudinal sectional view showing a cap structure in the embodiment of FIG. 1, FIG. 4 is a plan view showing a writing portion of a small tube type writing instrument in the embodiment of FIG. 1, FIG. 5, FIG. 7, FIG.
FIGS. 6A and 6B are longitudinal sectional views showing main parts of another embodiment of the present invention, FIG. 6 is a horizontal sectional view taken along line AA of FIG. 5, and FIG. 8 is taken along line AA of FIG. FIG. 9 is a horizontal cross-sectional view showing the line BB in FIG. 1.11, 21 …… Writing part shaft 1A …… Ink storage chamber of writing part shaft 1B ・ 21B …… Sealing part of writing part shaft 1 ・ 21 1C …… Tip of writing part shaft 1 sealing part 11D ・ 21D… … Engagement protrusions 11E ・ 21E of writing part shafts 11 ・ 21 …… Concave groove of writing part shafts 11 ・ 21 ………… Spindle 2A …… Air holes in tip shaft 2 ・ 14 …… Small diameter nib 8. 18 ・ 28 …… Cap 8A …… Rib of cap 8 8B ・ 28B …… Sealing part of cap 8.28 8C …… Sealing part of cap 8 Opening side edge 8D …… Opening part of cap 8E …… Cap 8 Engagement protrusion 8F …… Concave groove of cap 8 18G …… Inner surface of cap 18 ………… Seal member

Claims (1)

[Scope of utility model registration request] 1. A sealing portion is formed on a writing portion having a small-diameter pen tip attached to the tip, and an air hole for adjusting an internal pressure of an ink storage portion is sealed by fitting a sealing portion of a cap to the sealing portion. At the same time, in the sealing cap structure of the small tube type writing instrument that presses the small diameter nib against the elastic seal member in the cap to seal the small diameter nib, the longitudinal sealing distance between the sealing part of the cap and the sealing part of the writing part is It is set to be shorter than the elastic deformation amount in the longitudinal direction of the seal member pressed by the small-diameter pen tip, and at two positions or longitudinal positions appropriately separated in the longitudinal direction on either the inner surface of the cap or the outer surface of the writing portion which are engaged with each other. Direction to form an engaging protrusion,
Moreover, the closed cap structure of the small tube type writing instrument is characterized in that the engaging projection is completely divided in the longitudinal direction to form a concave groove extending.