JP5637515B2 - Writing instrument cap - Google Patents

Description

  The present invention relates to caps for writing instruments such as fountain pens, water-based ballpoint pens, and sign pens that store ink inside the writing shaft.

  In a fountain pen, water-based ballpoint pen, sign pen, and other writing instrument cap that stores ink inside the writing shaft, in order to further prevent evaporation and drying of the ink from the tip of the ink, the bottomed outer cap is sealed In addition, a double cap method using an inner cap that further seals only the brush tip portion has been adopted. In this double cap method, let's surely prevent evaporation and drying of the ink stored inside the writing shaft by the double contact portion of the inner cap and the pen tip periphery and the outer cap and the writing shaft. However, it is difficult to accurately position both contact portions, and the tip of the brush tip advances excessively into the inner cap, compressing the air in the inner cap and Is easy to flow into the ink reservoir from the pen tip, so that one end is sealed with a spring fixed so as not to rotate with respect to the outer cap so that the inner cap can be moved in the front-rear direction of the outer cap. It has a structure in which a bottomed inner cap is fixed integrally.

In the writing instrument cap having this structure, when the writing axis is inserted into the writing instrument cap in order to attach the writing instrument cap to the writing axis, the writing tip portion provided at the tip of the writing axis is accommodated in the inner cap. Is done. The inner end of the inner end of the inner end of the inner end of the inner end of the inner end of the inner end of the inner end of the inner end of the inner end of the inner end of the inner end Thus, an inner cap space sealed by the peripheral edge of the writing shaft is formed.
As a result, the writing tip portion provided at the tip of the writing shaft is held in the sealed inner cap space in the inner cap, so that the ink stored in the writing shaft through the writing tip portion and the writing tip portion is evaporated. Drying can be prevented.
Moreover, in the writing instrument cap having the structure, when the writing tip portion is accommodated in the inner cap, the writing tip portion can be securely inserted into the inner cap, and when the writing tip portion is accommodated in the inner cap. In order to easily create the sealed space in the inner cap, at least one of the inner peripheral surface of the inner cap that contacts the inner cap and the peripheral edge of the writing shaft is in the crown direction of the cap (hereinafter, the same direction is referred to as the distal direction or the distal side) And the opposite direction is referred to as the rear end direction or the rear end side). Therefore, when inserting the writing shaft into the writing instrument cap, too much force is applied and the writing shaft tip periphery strongly contacts the inner cap in the writing instrument cap and pushes it toward the tip of the cap. An attempt to compress the sealed space within the inner cap occurs. However, the inner shaft that contacts the peripheral edge of the writing shaft moves in the distal direction due to the contraction of the spring, so that the pressing force against the inner cap from the peripheral edge of the writing shaft shaft can be reduced. It is possible to prevent excessive advancement in the interior. That is, by this, the sealed space formed in the inner cap is excessively compressed by the tip of the writing shaft, preventing the air in the inner cap space from flowing into the ink storage portion in the writing shaft through the writing tip portion, In addition, by pulling out the writing instrument cap from the writing shaft at the time of use, the negative pressure generated in the sealed space can prevent the ink from flowing backward from the inside of the ink storage portion and further leaking from the writing tip portion. Yes (see Patent Document 1).

However, in the writing instrument cap having the structure of the double cap method, the inner cap is fixed to the outer cap integrally with the spring, but in the case of holding only by the spring, the spring is caused by the weight of the inner cap. Since it extends unnecessarily, another holding means is required to prevent the expansion. As the holding means, a plurality of locking projections (hereinafter referred to as “undercut”) are generally formed on the inner peripheral surface of the outer cap. However, depending on the material of the outer cap, it may be difficult or impossible to form an undercut on the inner peripheral surface. In this case, when the inner cap is fixed to the outer cap so as to be movable in the front-rear direction, the inner cap and the outer ticket may be fixed by a joint member that can be expanded and contracted separately from the spring.
However, in this case, since the joint member is fixed by screwing from the inside of the inner cap, a hole through which the screw passes is formed at the bottom of the inner cap, so that the airtightness inside the inner cap is easily impaired. Therefore, in order to ensure the tightness in the inner cap, for example, it is necessary to tighten a sealing material such as an O-ring together with the screw, so that the structure of the cap itself is complicated and the number of parts is also increased. This increases and the efficiency of the manufacturing operation decreases, so that the manufacturing cost increases significantly.

  In addition, since the outer cap and the inner cap are integrally fixed by a spring, even if the writing shaft tip peripheral edge abuts on the inner cap and oscillates when pushing toward the outer cap tip direction, the inner cap Since the spring and the spring, and the spring and the outer cap are integrated with each other, the spring receives the swing, and the inner cap can be appropriately guided toward the distal end of the outer cap. However, when a writing tool cap is attached to the writing shaft, the writing shaft is not necessarily inserted straight into the writing tool cap, and the writing shaft is rotated consciously or unconsciously with respect to the writing tool cap. Pushing can happen. At that time, since the outer cap and the inner cap are integrally fixed by the spring, if a heavy rotational force acts on the inner cap, the spring is destroyed.

By the way, in order to mount the writing instrument cap on the writing shaft, there is one in which the writing tool cap and the writing shaft are screwed together. In this case, when the inner cap is disposed in the outer cap, a screw groove is provided on the inner peripheral surface of the rear end of the outer cap, and the outer cap of the writing instrument cap is screwed into the screw groove outside the writing shaft. The writing shaft advances while rotating in the outer cap, and the writing tip portion provided at the tip of the writing shaft is accommodated in the inner cap. However, at that time, it is difficult to accurately position the screwing position of the outer cap and the writing shaft and the position where the writing tip portion is accommodated with respect to the inner cap, so that the inner cap can be moved in the front-rear direction of the outer cap. Therefore, it is conceivable to use a spring as in the double cap method.
However, the inner cap is integrated with the spring, and the spring is firmly fixed so as not to rotate or swing with respect to the inner cap and the outer cap so as to reliably receive the pressure when the writing shaft is inserted. It is what. Therefore, even when the writing shaft tip periphery comes into strong contact with the inner cap, there is no friction between them, and if the inner cap does not rotate with the rotation of the writing shaft, there is no need to know. The inner cap rotates with the rotation, and the spring integrated with the inner cap is damaged. If the spring is not damaged, the spring that is twisted while being pushed by the inner cap that rotates by the rotating writing shaft will rebound to return to its original shape, and the operator will When the hand is released from the shaft, the inner cap is pushed in the reverse direction while rotating in the reverse direction, and the writing shaft tip is excessively advanced into the inner cap. As a result, the inner cap space formed in the inner cap is excessively compressed by the tip of the writing shaft, and the air in the inner cap space flows into the ink storage portion through the writing tip portion. The negative pressure generated in the inner cap space may cause the ink to flow backward from the inside of the ink reservoir and further leak out from the writing tip.

  Further, the screwing of the writing instrument cap is repeated many times over a long period of time. Therefore, wear and damage are likely to occur between the inner peripheral surface of the inner cap and the rotating peripheral edge of the writing shaft. As a result, even if the writing instrument cap is attached to the writing shaft, the sealing inside the inner cap is likely to be lowered, and the ink stored in the writing shaft through the writing tip portion and the writing tip portion is likely to evaporate and dry. But there is.

Japanese Patent Laid-Open No. 11-32181

  The problem to be solved is that when the writing cap is attached to the writing shaft, the writing cap is damaged or its usefulness is lost when the writing shaft is rotated. In particular, in the case where the cap for the writing instrument is screwed onto the writing shaft, it is difficult to apply the conventional double cap method, and even if it can be applied, the tip of the writing shaft will advance excessively within the inner cap. In other words, the negative pressure generated when the writing instrument cap is pulled out causes the ink to flow backward from the inside of the ink storage section, and the leakage from the writing section is likely to occur. It is a point that the airtightness is liable to be lowered when holding.

  In the present invention, when attaching the writing instrument cap to the writing shaft, the inner shaft is placed in the front-rear direction of the outer cap in order to closely contact the tip of the writing shaft with the inner cap and prevent excessive advancement in the inner cap. The main feature is that it is movable and is rotatable along the inner peripheral surface direction of the outer cap in accordance with the rotation of the writing shaft.

As the first feature,
An outer cap that seals one end to have a bottomed shape, an inner cap that seals one end to have a bottomed shape, and an elastic body,
The inner cap is inserted in the outer cap with the bottom in the same direction, and is movable in the front-rear direction of the outer cap and is rotatable so as to be rotatable along the inner peripheral surface direction of the outer cap.
The elastic body is rotatable with respect to at least one of the caps between the inner periphery of the outer cap bottom and the outer periphery of the inner cap bottom, and presses the inner cap toward the rear end of the outer cap. Is sandwiched between
While connecting the bottom of the outer cap and the bottom of the inner cap through a rod-shaped elastic body holding body having a thin plate-like elastic body holding collar at the center,
With respect to the elastic body holder, at least one of the outer cap and the inner cap is movable in the front-rear direction of the outer cap,
When the elastic body is an outer cap that is movable in the front-rear direction of the outer cap with respect to the elastic body holding body, the elastic body is located between the inner peripheral surface of the outer cap bottom and the elastic body holding collar, and In the case of the inner cap, the inner cap is provided along the elastic body holding body between the inner cap bottom outer peripheral surface and the elastic body holding collar .

Therefore, when a writing instrument cap is attached to a writing shaft having a writing tip at the tip, when the writing shaft advances in the outer cap and abuts against the inner cap, and the writing shaft is further pressed, the inner cap Since the elastic body is compressed and moved toward the tip of the outer cap, the writing shaft does not advance excessively in the inner cap, and the space in the inner cap that seals the writing tip may be excessively compressed. Absent. As a result, when the writing tool cap is attached to the writing shaft, the air in the inner cap is not compressed by the tip of the writing shaft and flows into the ink reservoir through the writing tip portion. When the cap is removed, the negative pressure that is generated in the space inside the inner cap does not cause the backflow of ink or the leakage of ink from the writing tip.
In addition, when the writing shaft moves forward in the outer cap, the elastic body can be rotated with at least one of the outer cap and the inner cap even if rotation is added to the writing shaft. It is possible to prevent the elastic body from being damaged.
Further, since the inner cap is pushed toward the rear end of the outer cap by the elastic force of the elastic body, the inner cap and the tip periphery of the writing shaft are securely in contact with each other, and the inner cap is sealed. It can be ensured sufficiently, and ink evaporation and drying can be surely prevented.
In addition, as an elastic body which comprises a writing instrument cap here, resin, such as silicon and urethane, rubber | gum, etc. other than a spring are suitable.

In addition , since the inner cap is held by the elastic body holding body with respect to the outer cap, it is possible to simplify the structure by eliminating the need for undercutting in the writing instrument cap and to apply various materials to the outer cap. It is possible to improve the efficiency of the manufacturing work. As a result, the manufacturing cost of the writing instrument cap can be reduced.

Based on the first feature, as the second feature,
Let the elastic body be a spring,
The elastic body holding base formed integrally with the inner cap on the outer peripheral surface of the bottom of the inner cap has a smaller diameter than the outer periphery of the inner cap bottom, and forms a step portion with the outer periphery of the inner cap bottom. In addition, the inside of the interior is hollow, and a mounting hole that communicates with the interior is disposed at the tip of the interior, and a slit that is continuous with the mounting hole and opens on the side surface is disposed.
The elastic body holding body is made of metal, and in addition to the thin plate-like elastic body holding collar provided at the approximate center of the holding shaft, an outer cap mounting portion is provided at one end of the holding shaft and a thin plate-like engagement is provided at the other end. The thickness of each of the thin plate-like locking hooks is larger than the thickness of the hollow part so that the hollow part inside the elastic body holding base can be moved in the front-rear direction. It is made thin enough,
The locking hook portion of the elastic body holding body is inserted into a spring that is disposed on the elastic body holding base portion and contacts the stepped portion on the outer periphery of the inner cap bottom portion, and the locking hook portion is placed on the side surface of the elastic body holding base portion. By locking to the mounting hole through the opening slit, the inner cap can be moved in the front-rear direction only within the movable range of the locking collar portion in the hollow portion inside the elastic body holding base with respect to the elastic body holding body. In addition, the spring is sandwiched between the stepped portion on the outer periphery of the bottom portion of the inner cap and the elastic body holding collar portion of the elastic body holding body so as to be extendable and contractible,
By fixing the outer cap mounting portion of the elastic body holder to the outer cap,
The inner cap is movable in the front-rear direction of the outer cap and is rotatable along the inner peripheral surface direction of the outer cap.

  Therefore, the elastic body holder made of metal has high wear resistance, and can withstand the attachment and detachment of the writing shaft to the writing instrument cap many times. When the outer cap and the inner cap are held by the elastic body holding body including the spring, the spring is disposed on the outer periphery of the elastic body holding base portion of the inner cap, and the elastic body holding body penetrated into the spring is locked. Since it is only necessary to lock the collar part in the mounting hole of the elastic body holding base and to fix the outer cap mounting part of the elastic body holding body to the outer cap, it is possible to simplify and speed up the manufacturing work. The manufacturing cost can be reduced.

Based on the first feature and the second feature, as the third feature,
A taper surface is formed on one of the inner peripheral surface on the opening side of the inner cap and the writing shaft tip peripheral edge in contact with the inner peripheral surface on the opening side of the inner cap, and a step peripheral edge is formed on the other. It is.

Therefore, when the writing shaft moves forward in the writing instrument cap and the inner cap and the writing shaft tip periphery come into contact with each other, the pressure due to the advancement of the writing shaft concentrates on the step of the step periphery that comes into contact with the tapered surface. Therefore, the inner cap and the writing shaft tip peripheral edge are more closely adhered to each other.
As a result, the degree of sealing between the inner cap and the peripheral edge of the writing shaft is improved, so that ink evaporation and drying in the ink storage portion through the writing tip portion and the writing tip portion can be prevented.

  In particular, for the inner cap, a material that is more flexible than the outer cap such as polypropylene is generally used in consideration of airtightness in the inner cap and permeability of moisture and the like. For this reason, the inner cap and the writing shaft tip periphery come into contact with each other, and the pressure concentrates at the step periphery that contacts the tapered surface. To be. As a result, the degree of sealing between the inner cap and the peripheral edge of the writing shaft is further improved, so that it is possible to further prevent evaporation and drying of ink in the ink tip portion and the ink storage portion through the tip portion.

Based on the second and third features, the fourth feature is:
Each of the outer cap and the writing shaft has a threaded portion that is screwed together, and the rotation direction of the inner cap and the winding direction of the spring during the screwing are reversed.

Therefore, by screwing the writing shaft to the writing instrument cap, the writing shaft abuts on the inner cap, the inner cap rotates together with the writing portion, and even if the spring is rotated, The end escapes without being caught with respect to the elastic body holding collar portion constituting the elastic body holding body. As a result, the end of the spring and the elastic body holding hook portion constituting the elastic body holding body are caught and the rotation resistance of the inner cap does not occur, so that the writing instrument cap is smoothly screwed with respect to the writing shaft. Will be worn.
Further, the end of the spring does not wear or damage the elastic body holding collar of the elastic body holding body.

  The writing instrument cap according to the present invention is capable of preventing the ink from evaporating and drying by securely sealing the writing tip portion by securely bringing the writing cap into close contact with the inner cap held in the writing instrument cap. Inhibits excessive advance of the writing shaft tip inside and prevents leakage of ink from the writing tip due to the negative pressure generated in the inner cap when the writing instrument cap is pulled out. It has an excellent effect that can be used. In particular, in the type in which the writing instrument cap is screwed onto the writing shaft, the effect is further exhibited.

FIG. 1 is a front view of a fountain pen including a writing instrument cap according to an embodiment of the present invention. FIG. 2 is a front view of a fountain pen writing instrument cap and a writing shaft each having a writing instrument cap according to an embodiment of the present invention. FIG. 3 is a longitudinal sectional view of a fountain pen including a writing instrument cap according to an embodiment of the present invention. FIG. 4 is an enlarged longitudinal sectional view of a main part of a fountain pen including a writing instrument cap according to an embodiment of the present invention. FIG. 5 is an exploded perspective view of a writing instrument cap according to an embodiment of the present invention. FIG. 6 is a partial perspective view showing an assembled state of the inner cap and the spring in the writing instrument cap according to the embodiment of the present invention. FIG. 7 is a diagram showing a contact process between the writing shaft and the inner cap when the writing shaft is screwed to the writing instrument cap. FIG. 8 is an enlarged cross-sectional view of a main part showing a contact state between the writing shaft and the inner cap.

  While ensuring the sealing between the inner cap and the writing shaft to prevent drying of the ink, backflow of ink due to negative pressure generated when pulling out the writing instrument cap from the writing shaft, and further leakage of ink from the writing tip The purpose of preventing was realized by enabling the inner cap to move in the front-rear direction with respect to the outer cap and allowing the inner cap to rotate along the inner cap surface direction.

  1 is a fountain pen having a writing instrument cap according to the present invention, and the fountain pen 1 includes a writing instrument cap 9 and a writing shaft 2 according to an embodiment of the present invention. As shown in FIG. 2, the writing tool cap 9 is attached to the writing shaft 2 by screwing the male screw portion 3 of the writing shaft 2 and the female screw portion 10 of the writing tool cap 9. .

  The writing shaft 2 has a nib 4 as a nib part at the tip, a cartridge 5 for storing ink therein, and the cartridge 5 to the nib 4 between the nib 4 and the cartridge 5. The pen core 6 for appropriately adjusting the ink supply is arranged so as to be continuous continuously.

On the other hand, the writing instrument cap 9 which is an embodiment of the present invention has a bottomed shape with one end sealed, and an outer cap 11 on which a clip 12 that can be locked to clothes or the like is disposed on the outer peripheral surface of the distal end side. The inner cap 13 and the inner cap 13 have a bottomed shape in which one end is sealed in the outer cap 11, and the pen tip 4 provided at the tip of the writing shaft 2 is sealed in the inner cap space 14 formed inside the outer cap 11. And an elastic body holding body 22 that communicates with the outer cap 11 and a spring 21 that is an elastic body with one end held between the inner cap 13.
The inner cap 13 is movable in the front-rear direction while holding the spring 21 between the elastic body holding collar portion 27 of the elastic body holding body 22 that abuts the bottom portion 11a located on the distal end side of the outer cap 11. Further, the outer cap 11 is held so as to be rotatable along the inner peripheral surface direction.

That is, as shown in FIG. 4, the inner cap 13 is held in the outer cap 11 constituting the writing instrument cap 9 so as to be rotatable and movable in the front-rear direction.
First, the elastic body holding body 22 is made of metal, and an outer cap mounting portion 24 in which a male screw portion 25 is screwed on an outer peripheral surface is formed on the distal end side of the holding shaft 23, and a thin disk (about 0.5 mm) is formed on the other end. The locking collar portion 26 having a thickness) is further formed in the substantially central portion, and a thin disc-shaped elastic body retaining collar portion 27 having a larger diameter is integrally formed therewith.
On the other hand, a through hole 11 b through which the outer cap mounting portion 24 of the elastic body holding body 22 communicates is formed in the bottom portion 11 a that is the distal end side of the outer cap 11.
An elastic body holding base 15 is integrally formed on the outer peripheral surface of the front end side of the bottom 13 a that is the front end side of the inner cap 13. The elastic body holding base portion 15 has a substantially cylindrical shape whose outer diameter is smaller than the outer diameter of the bottom portion of the inner cap 13, and a step portion 13 b is formed between the elastic body holding base portion 15 and the inner cap 13. Further, the inside is a hollow portion 15a having a height h of about 3 mm in the front-rear direction, and an attachment hole 16 communicating with the inside is disposed on the tip side thereof, and is continuous to the attachment hole 16. A slit 17 is provided on the side surface.

Therefore, the spring 21 is arranged on the outer periphery of the elastic body holding base 15 of the inner cap 13, and the locking hook portion 26 of the elastic body holding body 22 is inserted from the distal end side of the spring 21, and the locking hook portion 26 is elastically moved. The spring 21 is held between the stepped portion 13b of the inner cap 13 and the elastic body holding collar portion 27 in an extendable manner by being locked to the mounting hole 16 through the slit 17 opened on the side surface of the body holding base portion 15. .
Then, the outer cap attaching portion 24 of the elastic body holding body 22 is passed through the through hole 11b formed in the bottom portion 11a of the outer cap 11 and the clip attaching hole 12a formed in the end portion of the clip 12, The inner cap 13 is held in the outer cap 11 by screwing the nut 29 together with the washer 28 into the male screw portion 25 of the outer cap mounting portion 24 protruding in the distal direction from the clip mounting hole 12a. .
Further, a substantially spindle-shaped crown 30 is attached to the top of the outer cap 11 by using an outer cap attaching portion 24 screwed with the nut 29.
As a result, the inner cap 13 is movable in the front-rear direction of the outer cap 11, and is rotatable along the inner peripheral surface direction of the outer cap 11. That is, if a pressing force toward the distal end of the outer cap 11 is not applied to the inner cap 13, the inner cap is pressed toward the rear end side of the outer cap 11 by the elastic force of the spring 21 to hold the elastic body. The surface on the distal end side of the locking collar portion 26 of the body 22 is in contact with the surface on the distal end side of the hollow portion 15a of the elastic body holding base portion 15 (state shown in FIG. 4). However, when a pressing force in the direction of the distal end of the outer cap 11 is applied to the inner cap 13, the inner cap 13 compresses the spring 21, while the rear end side of the locking collar portion 26 of the elastic body holding body 22. This surface moves until it comes into contact with the surface on the rear end side of the hollow portion 15 a of the elastic body holding base 15. When the pressing force is lost, the inner cap 13 is restored to the original position by the elastic force of the spring 21. Further, the inner cap 13 is merely one member that sandwiches the spring 21, and is not engaged / fixed with the spring 21, and the locking collar portion 26 of the elastic body holding body 22 is the elastic body holding base portion 15. It is possible to rotate along the inner peripheral surface direction of the outer cap 11 because it is only held by being locked in the mounting hole 16.
The spring 21 is not engaged / fixed with either the inner cap 13 or the elastic body holding collar 27.

Incidentally, as shown in FIG. 8, the tip peripheral edge 7 of the writing shaft 2 is formed with a tapered surface 8 that decreases in diameter toward the tip, whereas the inner end of the writing shaft 2 is in contact with the tip peripheral edge 7. A step edge 19 is formed at the opening edge 18 of the cap 13. The step edge 19 is provided with a step 20 which is an inward corner.
Therefore, when the writing tool cap 9 is mounted on the writing shaft 2, the tapered surface 8 of the tip peripheral edge 7 of the writing shaft 2 moving forward in the writing tool cap 9 contacts the step 20 of the step peripheral edge 19 of the inner cap 13. The two are surely brought into close contact with each other, but the writing shaft 2 is further screwed in the writing tool cap 9 by screwing with the writing shaft 2 in order to completely attach the writing tool cap 9. When advanced, the pressure concentrates on the tapered surface 8 formed on the tip periphery 7 of the writing shaft 2 through the step 20 of the step periphery 19 of the inner cap 13. As a result, the close contact between the tapered surface 8 of the tip periphery 7 of the writing shaft 2 and the step 20 of the step periphery 19 of the inner cap 13 is increased, and the degree of sealing in the inner cap 13 is further increased.

Further, the spring 21 held by the elastic body holding body 22 with respect to the inner cap 13 is a left-handed direction opposite to the direction of rotation when the writing shaft 2 is screwed to the writing instrument cap 9, that is, the clockwise rotation. ing. Therefore, when the writing tool cap 9 is attached to the writing shaft 2, when the writing shaft 2 is rotated clockwise with respect to the writing tool cap 9, the inner cap 13 that comes into contact with the peripheral edge 7 of the writing shaft 2 is brought together with the writing shaft 2. When the spring 21 rotates together with the inner cap 13 to the right when viewed from the rear end side, the sharpened end 21a of the spring 21 rotates at the front end. Therefore, the end 21a of the spring 21 is not caught by the elastic body holding collar 26 of the elastic body holding body 22. Therefore, not only the inner cap 13 rotates smoothly, but also the end 21a does not wear or damage the elastic body holding collar 26 by the rotation, so that the writing instrument cap 9 can be used many times. It is possible.
In particular, since the elastic body holder 22 is made of metal, it has high wear resistance, and is more effective for many times of attaching and detaching the writing instrument cap 9.

Since the writing instrument cap 9 of the present invention has the above-described configuration, when the writing instrument cap 9 is attached to the writing shaft 2, it is as follows.
That is, as shown in FIG. 7, when the writing shaft 2 is screwed onto the writing tool cap 9, the writing shaft 2 advances in the writing tool cap 9 (see FIG. A). When the screwing between the writing shaft 2 and the writing instrument cap 9 is further advanced, the tapered surface 8 formed at the tip peripheral edge 7 of the writing shaft 2 moving forward in the writing instrument cap 9 and the stepped peripheral edge 19 of the inner cap 13. To the step 20 (see FIG. B). Further, in order to completely attach the writing instrument cap 9 to the writing axis 2, the writing axis 2 may be screwed to the writing instrument cap 9 and the writing axis 2 may be advanced in the writing instrument cap 9. Since the inner cap 13 that is in contact with the writing shaft 2 is held together with the spring 21 so as to be rotatable with respect to the outer cap 11, the inner cap 13 rotates together with the writing shaft 2 and compresses the spring 21 in the outer cap 11. While moving forward. At this time, from the state in which the surface on the distal end side of the locking hook portion 26 of the elastic body holding body 22 is in contact with the surface on the distal end side of the hollow portion 15a of the elastic body holding base 15, the locking of the elastic body holding body 22 is performed. The inner cap 13 moves forward in the outer cap 11 until the surface on the rear end side of the collar portion 26 comes into contact with the surface on the rear end side of the hollow portion 15a of the elastic body holding base 15 (see FIG. C). .
Since the inner cap 13 advances in this way, the writing shaft 2 that is in contact with the inner cap 13 does not advance excessively in the inner cap 13, so that it is formed in the inner cap 13 and the pen tip 4. The inner cap space 14 for sealing is not excessively compressed by the writing shaft 2.
At this time, as described above, the close contact between the step 20 at the step periphery 19 of the inner cap 13 and the tapered surface 8 of the tip periphery 7 of the writing shaft 2 is further strengthened. The sealing degree inside becomes higher. As a result, an inner cap space 14 that is securely sealed by the writing shaft 2 is formed in the inner cap 13, and an outer cap space 14 a that is sealed by screwing the outer cap 11 and the writing shaft 2 to the outside. Therefore, the pen tip 4 provided at the tip of the writing shaft 2 in the inner cap space 14 is securely sealed, so that the ink in the pen core 6 and the cartridge 5 is evaporated through the pen tip 4 and the pen tip 4. -Drying can be reliably prevented.

On the other hand, when the fountain pen 1 is used, even if the writing shaft 2 is rotated counterclockwise with respect to the writing tool cap 9 in order to release the screwing between the writing tool cap 9 and the writing shaft 2, Since the cap 13 does not advance excessively, no negative pressure is generated in the inner cap space 14 that seals the nib 4 formed by the writing shaft 2 in the inner cap 13.
As a result, when screwing between the writing instrument cap 9 and the writing shaft 2 is released, it is possible to prevent ink from flowing back from the pen core 6 and the cartridge body 5 through the pen tip 4 and leaking from the pen tip 4.

  Evaporation / drying of ink stored inside and leakage of ink can be reliably prevented, and it can be applied to applicators such as liquid cosmetics by changing the writing part and the type of ink.

1 Fountain pen 2 Writing shaft 3 Male thread 4 Pen tip
5 Cartridge 6 Pen Core 7 Tip Edge 8 Tapered Surface 9 Writing Tool Cap 10 Female Screw Part 11 Outer Cap 11a Bottom Part 11b Through Hole 12 Clip 12a Clip Mounting Hole 13 Inner Cap 13a Bottom Part 13b Stepped Part 14 Inner Cap Space 14a Outer Cap Space 15 Elastic body holding base portion 15a Hollow portion 16 Mounting hole 17 Slit 18 Open edge 19 Step edge 20 Step 21 Spring 21a Terminal 22 Elastic body holding body 23 Holding shaft 24 Outer cap mounting portion 25 Male screw portion 26 Locking hook portion 27 Elastic body holding Buttock 28 washer 29 nut 30 crown

Claims (4)

An outer cap that seals one end to have a bottomed shape, an inner cap that seals one end to have a bottomed shape, and an elastic body,
The inner cap is inserted in the outer cap with the bottom in the same direction, and is movable in the front-rear direction of the outer cap and is rotatable so as to be rotatable along the inner peripheral surface direction of the outer cap.
The elastic body is rotatable with respect to at least one of the caps between the inner periphery of the outer cap bottom and the outer periphery of the inner cap bottom, and presses the inner cap toward the rear end of the outer cap. Is sandwiched between
While connecting the bottom of the outer cap and the bottom of the inner cap through a rod-shaped elastic body holding body having a thin plate-like elastic body holding collar at the center,
With respect to the elastic body holder, at least one of the outer cap and the inner cap is movable in the front-rear direction of the outer cap,
When the elastic body is an outer cap that is movable in the front-rear direction of the outer cap with respect to the elastic body holding body, the elastic body is located between the inner peripheral surface of the outer cap bottom and the elastic body holding collar, and In the case of the inner cap, between the inner cap bottom outer peripheral surface and the elastic body holding collar, respectively, is provided along the elastic body holding body,
A writing instrument cap characterized by that. Let the elastic body be a spring,
The elastic body holding base formed integrally with the inner cap on the outer peripheral surface of the bottom of the inner cap has a smaller diameter than the outer periphery of the inner cap bottom, and forms a step portion with the outer periphery of the inner cap bottom. In addition, the inside of the interior is hollow, and a mounting hole that communicates with the interior is disposed at the tip of the interior, and a slit that is continuous with the mounting hole and opens on the side surface is disposed.
The elastic body holding body is made of metal, and in addition to the thin plate-like elastic body holding collar provided at the approximate center of the holding shaft, an outer cap mounting portion is provided at one end of the holding shaft and a thin plate-like engagement is provided at the other end. The thickness of each of the thin plate-like locking hooks is larger than the thickness of the hollow part so that the hollow part inside the elastic body holding base can be moved in the front-rear direction. It is made thin enough,
The locking hook portion of the elastic body holding body is inserted into a spring that is disposed on the elastic body holding base portion and contacts the stepped portion on the outer periphery of the inner cap bottom portion, and the locking hook portion is placed on the side surface of the elastic body holding base portion. By locking to the mounting hole through the opening slit, the inner cap can be moved in the front-rear direction only within the movable range of the locking collar portion in the hollow portion inside the elastic body holding base with respect to the elastic body holding body. In addition, the spring is sandwiched between the stepped portion on the outer periphery of the bottom portion of the inner cap and the elastic body holding collar portion of the elastic body holding body so as to be extendable and contractible,
By fixing the outer cap mounting portion of the elastic body holder to the outer cap,
The writing instrument cap according to claim 1, wherein the inner cap is movable in the front-rear direction of the outer cap and is rotatable along the inner peripheral surface direction of the outer cap. A tapered surface is formed on one of the inner peripheral surface on the opening side of the inner cap and a peripheral edge of the writing shaft in contact with the inner peripheral surface on the opening side of the inner cap, and a stepped peripheral edge is formed on the other. The writing instrument cap according to claim 1 or 2, wherein Each of the outer cap and the writing shaft has a threaded portion that is screwed to each other, and the rotation direction of the inner cap and the winding direction of the spring at the time of the screwing are reversed. Item 2. A cap for a writing instrument according to item 3 or 3 .

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