JP7498685B2 - Writing implements - Google Patents

Description

Article 30, paragraph 2 of the Patent Act applies (1) Name of the meeting: 2016 Product Research Society New Product Announcement Event (Osaka venue) Date held: August 26, 2016 (2) Name of the meeting: 2016 Product Research Society New Product Announcement Event (Tokyo venue) Date held: September 8-9, 2016 (3) Date of sale: October 14, 2016

The present invention relates to an improvement to a writing instrument comprising a barrel and a refill having a writing part housed within the barrel and protruding from the front end of the barrel .

2. Description of the Related Art In ballpoint pens, mechanical pencils, or multi-function writing implements having a plurality of writing elements housed within a barrel, the surface of the barrel is often decorated to impart a sense of beauty.
In this case, for writing instruments in a comparatively low price range, there have been proposals for applying decorative treatment such as painting, decal printing, plating, etc., directly to the barrel (see Patent Document 1).
There has also been a proposal to laminate a transfer film on the surface of the barrel, on which an image is formed by color printing or the like (see Patent Document 2).

However, the writing instrument disclosed in Patent Document 1 has problems such as poor wear resistance and corrosion resistance in the decorative parts, and the base of the barrel becomes exposed and unsightly over time.
In addition, the writing instrument disclosed in Patent Document 2 has a film with a transferred color print attached to the barrel, which has problems such as the film peeling off with use and the barrel being slippery and lacking in grip.

Therefore, in order to ensure the durability of the barrel surface, a writing instrument has been proposed in which a high-hardness protective film (metal coating) is applied to the barrel (see Patent Document 3).
According to the writing instrument shown in Patent Document 3, the high-hardness metal coating gives the writing instrument a deep luster, improving the quality of its appearance and contributing to giving the writing instrument a luxurious feel.

International Publication No. 2013/008811 JP 2010-253842 A Japanese Utility Model Application Publication No. 60-173380

In this type of writing instrument, the barrel is composed of a front barrel and a rear barrel, and the two are detachably connected by a combination of male and female threads, and a tip part is detachably connected to the tip of the front barrel by a combination of male and female threads. When replacing the refill housed in the barrel, it is desirable to do so with the front barrel removed from the rear barrel. However, a ferrule is attached to the tip of the front barrel as a tip member, and the two are screwed together using a female and male thread.
Therefore, users who are not familiar with replacing refills may attempt to replace the refill with the ferrule removed from the front barrel. This requires users to remove the refill from the refill attachment part of the knock rod by pinching only the tip of the refill that protrudes slightly from the front barrel, and then attach a new refill to the knock rod away from their hand, which makes the refill replacement operation difficult .

Therefore, this invention aims to provide a writing instrument that solves the above-mentioned problem by configuring the rotation direction of the screw to release the connection between the front barrel and the rear barrel to be opposite to each other .

The writing instrument of the present invention, which has been made to solve the above-mentioned problems, is a writing instrument consisting of a barrel and a refill with a writing part that is housed within the barrel and protrudes from the front end of the barrel, wherein the barrel is composed of a front barrel and a rear barrel that are detachably connected to each other by a combination of male and female threads, and a tip part is detachably connected to the tip of the front barrel by a combination of male and female threads, and the rotation direction of the threads of the front barrel to disengage from the rear barrel is a left rotation , and the rotation direction of the threads of the tip part to disengage from the front barrel is a right rotation .

According to the writing instrument of this invention, the rotation direction of the screw of the front barrel to disengage from the rear barrel is a left rotation, and the rotation direction of the screw of the tip portion to disengage from the front barrel is a right rotation, thereby providing a writing instrument that solves the above-mentioned problem.

1A is a front view, FIG. 1B is a right side view, and FIG. 1C is a rear view of a multi-function writing instrument according to an embodiment of the present invention. 2 is a central cross-sectional view of the multi-function writing instrument shown in FIG. 1 . 2A is a front view, FIG. 2B is a right side view, and FIG. 2C is a cross-sectional view of a rear barrel used in the multifunction writing instrument shown in FIG. 1 . 4 is an enlarged cross-sectional view taken along line IV-IV in FIG. 3(C) and seen in the direction of the arrows. 2A is a front view, FIG. 2B is a right side view, FIG. 2C is a rear view, and FIG. 2D is a cross-sectional view of an inner cylinder used in the multifunction writing instrument shown in FIG. 1 . 2A and 2B are a front view and a cross-sectional view, respectively, of a front barrel used in the multifunction writing instrument shown in FIG. 2A and 2B are a front view and a cross-sectional view, respectively, of a ferrule used in the multifunction writing instrument shown in FIG. 2A is a front view, FIG. 2B is a right side view, and FIG. 2C is a rear view of a knock bar used in the multifunction writing instrument shown in FIG. 1 . 9 is an enlarged cross-sectional view taken along line IX-IX in FIG. 8(B) and seen in the direction of the arrows. 3 is an enlarged cross-sectional view taken along line XX in FIG. 2, as viewed in the direction of the arrows. FIG. 3 is an enlarged view of the crown portion of the multi-purpose writing instrument shown in FIG. 2 . 3 is a cross-sectional view showing a state in which one writing part is protruded in the multi-function writing instrument shown in FIG. 2.

An example in which the present invention is applied to a multi-function writing instrument will be described with reference to the drawings.
(1) Appearance of the Writing Instrument The writing instrument according to the embodiment is a multi-function writing instrument 10 having an appearance as shown in Figures 1(A) to 1(C). Note that Figure 1 shows a non-writing state in which the tip writing portions of multiple refills stored inside the multi-function writing instrument 10 are all submerged.
In barrel tube 11, rear barrel 20 located on the rear end side and front barrel 40 located on the front end side are screwed together and joined. A ring member 12 is fitted between rear barrel 20 and front barrel 40. In addition, a ferrule 50 serving as a tip portion is screwed and attached to the front end of front barrel 40.
The rear barrel 20 is made of a metal material, and has three window holes 22, which are openings in the longitudinal direction, at its rear. A knock protrusion 62 provided on the outer surface of a knock bar 60, which is attached to the rear of the refill (described later), protrudes from each window hole 22. Each knock protrusion 62 is movable in the front-rear direction along the corresponding window hole 22.

A clip 13 is attached to the knock protrusion 62 located in the window hole 22 on the front side (Figs. 1(A) and (B)). The tip of the clip 13 protrudes toward the rear barrel 20 and contacts the clip protrusion 21 formed on the surface of the rear barrel 20 (Fig. 1(B)). The knock rod 60 to which the clip 13 is attached is connected to the rear end of a refill 70 that contains a thermochromic ink (described later) in an ink reservoir and has a friction device made of an elastomer material as a tip writing part. On the other hand, the other two knock rods 60 (see Fig. 1(C)) are connected to the rear ends of ballpoint pen refills 80 (described later) that have different ink colors. In other words, the multi-function writing instrument 10 according to this embodiment has three types of refills built in.

(2) Refill, inner cylinder 30 and guide cylinder 17
FIG. 2 is a cross-sectional view of the multi-function writing instrument 10 shown in FIG.
An inner cylinder 30 that houses each knock rod 60 and guides the forward and backward sliding of these knock rods 60 is attached to the rear side of the internal space of the rear axle 20. A guide cylinder 17 that guides the forward and backward movement of each refill is attached to the tip side of the inner cylinder 30. The guide cylinder 17 is provided with a total of three guide holes 18 through which each refill is inserted.

The tip of the knock bar 60 to which the clip 13 is attached is fitted with a refill 70 made of an elastomer material and equipped with a friction tool capable of easily changing the color of the thermochromic ink, as described above. The refill 70 has a structure in which a tip writing part 72 made of an elastomer friction tool is connected to the tip of an ink connection tube 71. The thermochromic ink is an ink that maintains a predetermined color (first color) at room temperature (e.g., 25°C), changes to another color (second color) when heated to a predetermined temperature (e.g., 65°C), and then returns to the original color (first color) when cooled to a predetermined temperature (e.g., -10°C). In general, the second color may be colorless, and the drawn lines drawn with the first color (e.g., red) may be made colorless by heating them. Thus, the friction tool rubs against the paper surface on which the drawn lines are written, generating frictional heat, which changes the drawn lines to colorless. Naturally, the second color may be a color other than colorless.
A spring 90 is fitted onto the rear outer periphery of the refill 70, which is provided with a tip writing portion formed by a friction tool. The rear end of the spring 90 abuts against the step 68 at the tip of the knock bar 60, and the tip of the spring 90 abuts against the step 19 at the tip of the guide hole 18. As the knock bar 60 slides toward the tip, the spring 90 is compressed between these steps 68, 19.

On the other hand, the ballpoint pen refill 80 is attached to the tip of the other two knock rods 60 as described above. The ballpoint pen refill 80 has a structure in which a ballpoint pen tip 82 as a tip writing part is connected to the tip of a tubular ink containing tube 81 that contains ink. One of the ink containing tubes 81 contains thermochromic ink that can be changed by a friction tool, and the other contains non-thermochromic ink that cannot be easily changed by a friction tool, and a writing instrument can be provided in which the refill is contained in a metal shaft that does not have a friction tool on the outer surface of the barrel, which can be easily switched depending on the usage situation. In addition, a spring 90 is also inserted on the rear outer circumference of the ballpoint pen refill 80, but this spring 90 is the same as the refill 70 with a tip writing part using a friction tool described above. In addition, a cushion material 14 is interposed between the rear end part of the inner tube 30 and the inside of the rear end of the barrel 11, but this will be described later.

(3) Rear axle 20
The rear axle 20 is made of metal or resin material, and as described above, the rear axle 20 has three window holes 22 (FIGS. 3(A) and (B) and FIG. 4). The rear end portions of both side edges of the window hole 22 located at the front protrude to face each other, and these portions form a pair of engagement pieces 23 (FIGS. 3(A) and 4). The rear end edge of the window hole 22 is also provided with a similar protruding portion, which connects the engagement pieces 23 on both sides (FIG. 3(A)).
A female thread 24 is formed on the inner circumference near the tip of rear barrel 20 for screwing with front barrel 40. Furthermore, the rear end of the internal space of rear barrel 20 forms a platform portion 25 that projects slightly towards the tip, and the tip surface thereof is flat. This flat surface is rear barrel rear end surface 26 (FIGS. 3(C) and 4), which is the surface with which cushion material 14 mentioned above comes into contact. This will be described later.

(4) Inner cylinder 30
The inner cylinder 30 also has a total of three openings 31 that correspond to and communicate with the respective window holes 22 of the rear axle 20 (FIGS. 5(A) to (D)). Along both edges of each opening 31, rails 32 that guide the forward and backward sliding of the knock bar 60 are provided (FIGS. 5(A) to (D)). The tip portion of each rail 32 is recessed toward the axial center, and this portion is referred to as a rail step 33 (FIGS. 5(A) to (D)).
The tip edge 34 of the inner cylinder 30 is a location where the tip portion of the knock bar 60 engages, as will be described later.
A rear end recess 35 into which the cushion material 14 is inserted is formed at the rear end of the inner tube 30. This will be described later.

(5) Front shaft 40
The inside of front barrel 40 is molded from a relatively hard resin material 41 such as polycarbonate resin, and on the outside of it is a grip portion 42 made of a metal material different from that of rear barrel 20 (FIGS. 6A and 6B). A male thread 43 that screws into rear barrel 20 is formed on the outer periphery of the rear end portion made of the hard resin on the inside (FIGS. 6A and 6B).
The hard resin material 41 has an inner periphery at its tip end with a female thread 44 so that the rear end of a nozzle 50 serving as a nozzle member can be screwed into it (FIG. 6B).

(6) Cap 50
The base 50 is made of metal, and the tip side is tapered 51, and the outer periphery of the approximately cylindrical portion on the rear end side is formed with a male thread 53 for screwing into the female thread 44 of the tip barrel 40 (FIGS. 7A and 7B). A tip opening 52 is formed at the tip of the tapered portion 51 (FIG. 7B), and the writing tip of each refill appears and disappears from here.

The base metal 50 may be made of a nickel-plated base material that has been coated with a coating.
However, there is a concern that nickel plating may dissolve the nickel when the user sweats, causing allergic symptoms (so-called metal allergies).
Therefore, after nickel plating, for example, a tin-cobalt alloy coating (tin-cobalt plating) is formed as a coating layer on the nickel plating, which effectively prevents the nickel in the nickel plating layer from dissolving due to sweating. This makes it possible to provide a writing instrument that eliminates the problem of causing allergic symptoms. This can also be applied to the barrel 11 (front barrel 40 and rear barrel 20).

(7) Knock bar 60
8 shows a knock rod 60 to which the clip 13 is attached. This knock rod 60 includes a knock rod insertion portion 61 (FIGS. 8(A) to (C)) that is inserted from the outside toward the tip end into the window hole 22 of the rear body 20 and the opening 31 of the inner cylinder 30, and a knock projection 62 (FIG. 8(B)) that is located behind the knock rod insertion portion 61 and projects outward.
A clip mounting portion 63 to which the clip 13 is attached protrudes further outward from the knock protrusion 62 (FIGS. 8A and 8B). In addition, a pair of engagement grooves 64 are formed on both rear ends of the base of the knock protrusion 62 (FIGS. 8B and 9).
When the tip end side of the knock rod 60 is inserted from the outside into the window hole 22 of the rear axle 20 and the opening 31 of the inner cylinder 30, and then moved slightly rearward along the rail 32, the engaging pieces 23 of the window hole 22 fit into these engaging grooves 64, as shown in Figure 10, preventing the knock rod 60 from falling outward. In other words, the engaging pieces 23 of the window hole 22 function as a retainer for the knock rod 60.

The reason why the knock rod 60 is attached by being inserted from the outside of the window hole 22 of the rear axle 20 is that the inner tube 30 and the guide tube 17 are inserted inside the rear axle 20, and there is no sufficient space to insert the knock rod 60 rearward from the tip of the rear axle 20.
On the other hand, an outwardly protruding locking projection 65 (FIG. 8B) is formed at the tip of the knock bar insertion portion 61. A locking step 66 located behind the locking projection 65 locks with the tip edge 34 of the inner cylinder 30 (see FIG. 2), which also contributes to preventing the knock bar 60 from coming out.

A release protrusion 69 is formed on the inside of the knock bar 60 along the longitudinal direction and protruding inward (FIGS. 8B and 8C). This release protrusion 69 is also provided on the other two knock protrusions 62, and in the non-writing state shown in FIG. 1, the release protrusions 69 are butted against each other toward the axis as shown in FIG. 10.
A refill attachment part 67 protrudes from the tip of the knock bar 60 in the tip direction (FIGS. 8A to 8C). This refill attachment part 67 is press-fitted into the rear end of a refill 70 equipped with a friction tool made of an elastomer material (see FIG. 2).

(8) Cushioning material 14
The cushioning material 14 is a member in which a convex portion 15 having a generally truncated cone shape that is slightly tapered toward the tip and a disk-shaped plate-shaped portion 16 continuing to the rear end thereof are integrally molded from silicone rubber, as shown in FIG. 11. Of the cushioning material 14, the convex portion 15 is inserted into the rear end recess 35 (see FIG. 5(D)) of the inner tube 30. The plate-shaped portion 16 abuts against the rear end surface 26 (see FIG. 3(C)) of the pedestal portion 25 of the rear axle 20. That is, the cushioning material 14 is a member interposed between the inner tube 30 and the rear axle 20. A shallow circular first recess 27 is formed at the rear end of the rear axle 20, and a deeper circular second recess 28 having the same center is also formed therein. A circular seal member 29 is fitted into the first recess 27.
Here, a chamfered portion 27A is formed on the periphery of the first recess 27, and a groove having an approximately V-shaped cross section is formed around the chamfered portion 27A and at the junction with the raised portion 27C of the first recess 27, this groove is referred to as an radiused groove 27B.

(9) Advancement and retreat of the refill In the state shown in FIG. 2, the knock bar 60 is located at the rear end, and the engagement piece 23 of the window hole 22 of the rear barrel 20 is fitted into the engagement groove 64 of the knock bar 60. When the knock bar 60 with the clip 13 attached is pressed toward the tip from this state, the knock bar 60 moves forward along the rail 32 (see FIG. 5(A)) of the inner cylinder 30 while compressing the spring 90. Then, when the knock bar 60 reaches the rail step 33 at the tip of the rail 32, it sinks toward the axial center. In this state, as shown in FIG. 12, the tip writing part 72 of the refill 70 by the friction tool protrudes from the tip opening 52 of the ferrule 50 (see FIG. 7(B)), and it becomes in a state where writing is possible. At this time, the release protrusion 69 of the knock bar 60 is engaged with the rail step 33. Due to this engagement, the tip writing part 72 is maintained in a protruding state against the biasing force of the compressed spring 90.

In this state, when one of the other two knock rods 60 is pressed toward the tip, the tip of the release protrusion 69 provided on that knock rod 60 comes into contact with the rear end of the release protrusion 69 that sinks toward the axial center and engages with the rail step 33 as described above, and bounces it up toward the periphery. This releases the engagement between the release protrusion 69 and the rail step 33. The knock rod 60 then moves rearward due to the biasing force of the compressed spring 90, and the protruding tip writing part retracts into the barrel 11, returning to the state shown in FIG. 2. At this time, the knock rod 60 is positioned at the rearmost end, and the engagement piece 23 of the window hole 22 of the rear barrel 20 fits again into the engagement groove 64 of the knock rod 60.

(10) Function of cushioning material 14 Here, even if the frequency of use of a particular refill (for example, a refill 70 having a writing tip 72 formed by a friction tool) is extremely higher than that of other ballpoint pen refills 80, the cushioning material 14 functions as follows.
That is, even if the knock bar 60 attached to the refill collides backward due to the biasing force of the spring 90 when released from the writable state, the knock bar 60 does not collide directly with the cushioning material 14. In other words, the knock bar 60 collides with the inner tube 30 in which it is housed. Therefore, the impact caused by the retraction of a specific refill is dispersed into a force that presses the entire inner tube 30 backward, and this dispersed force is buffered by the cushioning material 14 (see FIG. 11) interposed between the inner tube 30 and the rear barrel 20. Therefore, the cushioning material 14 does not wear unevenly only at a specific position (for example, the position corresponding to such a specific refill).

In the multi-function writing instrument described above, the refills 70, 80 housed in the barrel 11 can be replaced. When replacing the refills 70, 80, it is desirable to do so with the front barrel 40 removed from the rear barrel 20.
However, in the multifunction writing instrument shown in this embodiment, a ferrule 50 serving as a tip member is attached to the tip end side of the front barrel 40 , and the two are screwed together using a female thread 44 and a male thread 53 .
Therefore, a user who is not familiar with replacing refills may attempt to replace the refill with ferrule 50 removed from front barrel 40. This forces the user to pick up only the tip of the refill that protrudes slightly from front barrel 40, remove the refill from refill attachment portion 67 of knock rod 60, and then attach a new refill to knock rod 60 away from the user's hand, making the refill replacement operation difficult.

Therefore, in the multi-function writing instrument of this embodiment, the rotation direction of the screw to release the coupling of front barrel 40 to rear barrel 20 and the rotation direction of the screw to release the coupling of ferrule 50 to front barrel 40 are configured to be opposite to each other.
That is, in this embodiment, in order to release the connection of male threads 43 of front barrel 40 that is threadedly engaged with female threads 24 of rear barrel 20, the connection can be released by rotating front barrel 40 counterclockwise relative to rear barrel 20. In contrast, in order to release the connection of male threads 53 of ferrule 50 that is threadedly engaged with female threads 44 of front barrel 40, it is necessary to rotate ferrule 50 clockwise relative to front barrel 40.

Generally, to release a screwed state, it is customary to rotate the side to be removed left; however, in the writing instrument described above, even if ferrule 50 is rotated left, ferrule 50 will not be removed from front barrel 40; rather, the rotational force causes front barrel 40 to be released from its connected state with rear barrel 20.
Therefore, by setting the rotation direction for releasing the screw coupling to the above-mentioned relationship as described above, when replacing the refill, most users will inevitably perform the replacement operation with front barrel 40 removed from rear barrel 20.

On the other hand, in this multi-function writing instrument, in order to meet the high-class tastes of users, the surfaces of the front barrel 40 and the rear barrel 20 constituting the barrel 11 are coated with a metal coating as a protective film.
This metal coating is preferably a film-forming process by ion plating, which can create a deep metallic luster and provide a good grip. The film thickness is preferably 0.5 to 5 μm.
Table 1 shows the characteristics of the film formation process by ion plating (IP) and the film formation process by normal plating on the barrel 11, and it can be seen from Table 1 that in the example where the film formation process with a hardness of Hv700 or more is performed, a metal coating with excellent durability including corrosion resistance, abrasion resistance, and weather resistance is obtained. Regarding the durability shown in Table 1, A indicates excellent, B indicates good, and C indicates normal evaluation.
The metal coating obtained by this type of film formation process can be said to have better durability as its hardness increases, and taking productivity into consideration, a hardness in the range of Hv 1500 to 3000 is more preferable.
The Hv mentioned here is the Vickers hardness, which is measured by a commercially available micro Vickers tester (for example, the micro Vickers tester MVK-1C manufactured by Akashi (now Mitutoyo)).

However, in the above-mentioned multi-function writing implement, the metal coating on the surface tends to have a low coefficient of friction, which causes the fingertips to slip when the barrel is held, resulting in a poor grip. Tables 2 and 3 show the results of a comparison of the coefficient of friction between a barrel made of Cr plating, which can be treated with a film-forming process with a hardness of Hv700 or more to obtain a certain level of durability, and a barrel made of ion plating.
Table 3 shows an example in which a titanium nitride (TIN) film is formed on a Cr plating by ion plating.

For the measurements shown in Tables 2 and 3, the coefficient of friction between the surface of grip portion 42 of front barrel 40 shown in Fig. 6 and the surface of paper (high-quality paper) was measured, specifically using a commercially available surface measuring device (HEIDON-13D, Shinto Scientific Co., Ltd.). Then, front barrel 40 was brought into contact with the surface of the paper with a load of 2.5 N applied, and the frictional resistance was measured at a speed of 20 cm/sec and a measurement distance of 20 cm, to determine the coefficient of friction.
It should be noted that the "Y direction" shown in Tables 2 and 3 is the result when tip barrel 40 is moved on the page along the axial direction, and the "X direction" is the result when tip barrel 40 is moved on the page along a direction perpendicular to the axial direction.

As shown in Tables 2 and 3, three measurement results are shown for each sample, with "Ave" indicating the average value of the three measurement results, "Max" indicating the maximum value of the three measurement results, and "Min" indicating the minimum value of the three measurement results.
As shown in the results of Tables 2 and 3, no difference was observed in the friction direction measured separately in the "Y direction" and "X direction". Furthermore, compared to the Cr-plated axle shown in Table 2, the ion-plated (IP) axle tubes shown in Table 3 had a higher friction coefficient in all cases.

Furthermore, when the sample products measured were compared between the Cr-plated barrel and the ion-plated barrel, it was found that the ion-plated barrel was less slippery and had a better grip when actually held.
Therefore, from the comparison results shown in Tables 2 and 3, it can be seen that a friction coefficient of 0.23 or more is appropriate for a writing instrument having this type of metal coating on the barrel. It can be said that the higher the friction coefficient of the metal coating formed on the barrel, the better the grip, but in order to achieve both a moderate grip and hardness of the formed film, it is desirable for the friction coefficient to be 0.6 or less.

On the other hand, in a writing instrument in which a metal coating is formed on each of the front barrel 40 and the rear barrel 20 as described above, it is preferable that the color difference between the front and rear be maintained the same.
In this case, it is desirable that the color difference between the metal coating applied to front barrel 40 and the metal coating applied to rear barrel 20 be within the ranges of an L* value difference of 20 or less, an a* value difference of 10 or less, and a b* value difference of 10 or less in the L*a*b* color system.
This allows the difference in brightness indicated by the L* value to be appropriately suppressed, while also allowing the difference in color tone between red and green indicated by the a* value, and the difference in color tone between yellow and blue indicated by the b* value to be appropriately suppressed, providing a writing instrument with a well-balanced color tone in the axial direction.

The method for measuring the color of the front barrel 40 and rear barrel 20 described above is to photograph the surfaces of the components with a scanner, then print the image on paper and measure it using a color difference meter or the like.
In this case, the conditions for taking pictures with the scanner were as follows: the measurement device was a commercially available scanner (EPSON GT-X750), and the data was imported using the software that came with the scanner (EPSON Scan, also manufactured by EPSON).
Mode: Home mode,
Manuscript type: illustration,
Image Type: Color,
Output settings: Other,
Resolution: 400 dpi
Save file format: Bitmap,
Other settings: Default settings
Let us assume that.
The image captured by the scanner is printed on a sheet of paper such as photographic paper, and the color of the printed image is measured in accordance with JIS K 7375 using a general-purpose color difference meter (TC-8600A, manufactured by Tokyo Denshoku Co., Ltd.).

10. Writing implements (double-sided writing implements)
LIST OF SYMBOLS 11 Barrel 12 Ring member 13 Clip 14 Cushioning material 17 Guide tube 18 Guide hole 20 Rear barrel 21 Clip protrusion 22 Window hole 23 Engagement piece 24 Female thread 30 Inner barrel 31 Opening 32 Rail 33 Rail step 40 Front barrel 41 Resin material 42 Grip portion 43 Male thread 44 Female thread 50 Ferrule 51 Tapered portion 52 Tip opening 53 Male thread 60 Knock bar 61 Knock bar insertion portion 62 Knock protrusion 63 Clip attachment portion 64 Engagement groove 65 Locking protrusion 67 Refill attachment portion 69 Release protrusion 70 Refill equipped with friction device 71 Lead housing tube 72 Tip writing portion (friction device)
80 Ballpoint pen refill 81 Ink containing tube 82 Writing tip (ballpoint pen tip)
90 Spring

Claims (1)

A writing instrument comprising a barrel and a refill having a writing part housed in the barrel and protruding from a front end of the barrel,
The writing instrument is characterized in that the barrel is composed of a front barrel and a rear barrel, which are detachably connected to each other by a combination of male and female threads, and a tip portion is detachably connected to the tip of the front barrel by a combination of male and female threads, and the rotation direction of the threads of the front barrel to disengage from the rear barrel is a left rotation , and the rotation direction of the threads of the tip portion to disengage from the front barrel is a right rotation .

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