JP7645918B2 - Writing implement with erasing member - Google Patents

Description

The present invention relates to a writing instrument equipped with an erasing member.

A writing instrument is known that has a separate erasing member at the top of the cap, and that allows handwriting written on paper or the like with the writing instrument to be erased by the erasing member (for example, Patent Document 1).

Patent Document 2 also describes an attachment structure for attaching a soft member equivalent to an erasing member to the upper end of a cylindrical body such as the barrel or cap of a writing instrument. According to the attachment structure described in Patent Document 2, a protrusion is provided at the upper end of the cylindrical body, an attachment hole is provided at the lower end of the erasing member, and the protrusion is inserted into the attachment hole to fit it.

JP 2003-200694 A JP 2009-214515 A

The writing implement described in Patent Document 1 is designed to be replaced when the erasing member becomes worn out, and so the cap and the erasing member are not firmly attached. As a result, when the erasing member is used to rub handwriting, rattling can occur between the cap and the erasing member, making it difficult to erase stably.

In contrast, the mounting structure described in Patent Document 2 allows the erasing member to be firmly attached, but the contact area between the outer circumferential surface of the protrusion on the cylinder and the inner circumferential surface of the mounting hole in the erasing member increases as the protrusion is inserted into the mounting hole. In other words, the force against the frictional resistance required to insert the protrusion into the mounting hole, i.e., the pressure force, also increases accordingly, making it difficult to firmly insert the protrusion all the way into the mounting hole.

The present invention aims to provide a writing instrument with an erasing member that can be easily attached. It is also an object of the present invention to provide a writing instrument with an erasing member that is firmly attached.

According to one aspect of the present invention, a writing instrument is provided that includes a cap equipped with an erasing member and a barrel into which the cap fits, and a clip portion is integrally provided on the side of the cap via a connecting portion, the clip portion being a substantially rectangular plate-like member that extends in the axial direction.

In this specification, the writing tip side in the axial direction of the writing instrument is defined as the "front" side, and the side opposite the writing tip is defined as the "rear" side. Also, in the axial direction of the cap, the open end side into which the writing instrument body is inserted is defined as the "rear" side, and the opposite side is defined as the "front" side.

According to another aspect, the connection portion has a T-shaped cross-sectional shape.

In another aspect, a guide surface is formed on the front end surface of the clip portion so that the angle A between the paper surface and the central axis of the writing implement during the erasing operation is in the range of 40 to 80 degrees.

In another embodiment, the cap is made of a material that is harder than the portion of the barrel into which it fits.

In another embodiment, the width of the clip portion and the diameter of the cap are substantially the same, and the clip portion extends to the center of gravity of the writing instrument.

Each aspect has the common effect of providing a writing instrument with an erasing member that can be easily attached. Furthermore, each aspect has the effect of providing a writing instrument with an erasing member that is firmly attached.

1 is a longitudinal sectional view of a writing instrument according to a first embodiment having an erasing member according to one aspect of the present invention. FIG. 2 is a perspective view of the cap of the writing instrument shown in FIG. 1 . FIG. 3 is a vertical cross-sectional view of the cap shown in FIG. 2 . 3 is another vertical cross-sectional view of the cap shown in FIG. 2. 2 is a perspective view of an erasing member of the writing instrument shown in FIG. 1; FIG. 2 is another perspective view of the erasing member of the writing instrument shown in FIG. 1 . FIG. 6 is a vertical cross-sectional view of the erasing member shown in FIG. 5 . 2 is a perspective view of a cap to which an erasing member of the writing instrument shown in FIG. 1 is attached. FIG. FIG. 9 is a side view of the cap shown in FIG. 8 . 9 is a vertical cross-sectional view of the cap shown in FIG. 8 taken along line XX of FIG. 9 is another longitudinal cross-sectional view of the cap shown in FIG. 8 . 9 is a cross-sectional view of the cap shown in FIG. 8 taken along line YY in FIG. 9 is a cross-sectional view of the cap shown in FIG. 8 taken along line ZZ in FIG. 2 is an enlarged cross-sectional view showing an attachment portion of the erasing member and the cap of the writing instrument shown in FIG. 1. 2 is a perspective view of a cap of an alternative embodiment to the cap of the writing instrument shown in FIG. 1 . FIG. 16 is a longitudinal cross-sectional view of the cap shown in FIG. 15 . 2 is a perspective view of a cap to which an erasing member of a different embodiment from the erasing member of the writing instrument shown in FIG. 1 is attached. FIG. FIG. 18 is a longitudinal cross-sectional view of the cap shown in FIG. 17. FIG. 18 is a vertical cross-sectional view of the erasing member shown in FIG. 17. 2 is a perspective view of a cap to which an erasing member of a further embodiment different from the erasing member of the writing instrument shown in FIG. 1 is attached. FIG. FIG. 21 is a perspective view of the erasing member shown in FIG. 20 . FIG. 21 is a front view of the erasing member shown in FIG. 20. 2 is a perspective view of a cap to which an erasing member of a further embodiment different from the erasing member of the writing instrument shown in FIG. 1 is attached. FIG. FIG. 24 is a perspective view of the erasing member shown in FIG. 23 . FIG. 24 is a front view of the erasing member shown in FIG. 23. 2 is a perspective view of a cap to which an erasing member of a further embodiment different from the erasing member of the writing instrument shown in FIG. 1 is attached. FIG. FIG. 27 is a perspective view of the erasing member shown in FIG. 26 . FIG. 27 is a front view of the erasing member shown in FIG. 26. 2 is a perspective view of a cap to which an erasing member of a further embodiment different from the erasing member of the writing instrument shown in FIG. 1 is attached. FIG. FIG. 30 is a perspective view of the erasing member shown in FIG. 29 . FIG. 30 is a front view of the erasing member shown in FIG. 29. FIG. 2 is a longitudinal sectional view of a writing instrument according to a second embodiment, which includes an erasing member according to one aspect of the present invention. FIG. 33 is a perspective view of the cap of the writing instrument shown in FIG. 32. FIG. 34 is a plan view of the cap shown in FIG. 33. FIG. 34 is a side view of the cap shown in FIG. 33. FIG. 34 is a longitudinal cross-sectional view of the cap shown in FIG. 33. 35 is a cross-sectional view of the cap shown in FIG. 33 taken along line S-S in FIG. 35. FIG. 33 is a diagram showing a state in which the cap to which the erasing member of the writing instrument shown in FIG. 32 is attached is used during erasing.

The following describes in detail an embodiment of the present invention with reference to the drawings. Corresponding components are designated by the same reference symbols throughout the drawings.

1 is a longitudinal cross-sectional view of a writing instrument 1 according to a first embodiment of the present invention, which includes an erasing member 2. The writing instrument 1 is a ballpoint pen type writing instrument, and includes a writing instrument body 3 including a refill 5 and a cylindrically extending barrel 6, and a cap 4. The barrel 6 includes a cylindrical front barrel 7 and a rear barrel 8 whose front end is screwed into the rear end of the front barrel 7. The front barrel 7 and the rear barrel 8 are made of a resin material. For example, in this embodiment, the front barrel 7 is made of polypropylene resin, and the rear barrel 8 is made of polycarbonate resin. By forming the front barrel 7 from a material that is softer than the material of the cap 4 described later, it is possible to prevent cracking during fitting. A hole is formed at the front end of the front barrel 7 to allow the writing tip 11 of the refill 5 to protrude. In this specification, the writing tip side in the axial direction of the writing instrument 1 is defined as the "front" side, and the opposite side to the writing tip is defined as the "rear" side. Additionally, in the axial direction of the cap 4, the open end side into which the writing instrument body is inserted is defined as the "rear" side, and the opposite side is defined as the "front" side.

The refill 5 has a cylindrical refill body 9, a joint member 10, a writing tip 11, and a refill plug 12. The refill body 9 is formed of a resin material such as polypropylene or a metal material, and is configured to contain ink. The joint member 10 is formed of a resin material such as polypropylene, polybutylene terephthalate, polyacetal, or a metal material. The rear end of the writing tip 11 is attached to the front end of the joint member 10. The refill 5 is housed in the barrel 6, and a part of the writing tip 11 is exposed through the hole in the tip barrel 7 when housed in the barrel 6. The writing tip 11, which is the writing part, holds a ball at its tip, and the ink contained in the refill body 9 is ejected through the joint member 10 according to the rotation of the ball during writing. The refill plug 12 is pressed into the rear end of the refill body 9, and is attached by fitting due to this press-fit.

The cap 4 has a cap body 4a, a clip portion 4b, a seal member 13, and an erasing member 2. The cap body 4a is a cylindrical member, and the clip portion 4b is integrally provided on its side. The clip portion 4b is configured to have elasticity so that it can hold documents, clothes, and other items between the cap body 4a and the clip portion 4b. Therefore, examples of materials for forming the cap body 4a and the clip portion 4b include synthetic resins such as polycarbonate and acrylonitrile butadiene styrene. As mentioned above, it is desirable to form them from a material that is harder than the tip shaft 7.

The seal member 13 protects the writing tip 11 by engaging with the writing tip 11 when the cap 4 is attached to the tip barrel 7 and elastically deforming. Examples of materials for forming the seal member 13 include synthetic rubbers such as isopropylene rubber, butadiene rubber, nitrile rubber, silicone rubber, butyl rubber, ethylene propylene diene rubber, styrene butadiene rubber, and fluororubber. Butyl rubber (IIR) in particular can further improve the processability and volatilization prevention performance of the tip of the writing part. In other words, butyl rubber is not only excellent in processability, but also has excellent airtightness (gas barrier properties) among various rubbers. Therefore, by forming the seal member from butyl rubber, it is possible to more reliably prevent the writing tip from drying out and the solvent components in the ink from volatilizing.

Next, the structure of the cap 4 will be described with reference to Figures 2 to 4. Figure 2 is a perspective view of the cap 4 of the writing instrument shown in Figure 1, Figure 3 is a vertical cross-sectional view of the cap 4 shown in Figure 2, and Figure 4 is another vertical cross-sectional view of the cap 4 shown in Figure 2. Figure 4 is a cross-sectional view at a position rotated 90 degrees around the central axis from the cross-sectional view shown in Figure 3.

The cap body 4a has an engagement portion 4c on the inner wall near the open end that engages with the tip barrel 7. Three or more ribs 4e extending in the axial direction of the writing instrument 1 are provided at equal intervals in the circumferential direction on the inside of the front end 4d of the cap body 4a, i.e., near the top. In this embodiment, the cap body 4a has six ribs 4e. As shown in FIG. 1, the seal member 13 is sandwiched between the ribs 4e.

The ribs 4e each have the same axial length, but only the two ribs (long ribs) 4f arranged opposite to the central axis may extend further toward the rear of the cap 4 than the other ribs 4e. These long ribs 4f act as guides when inserting the seal member 13 when assembling the cap 4, making insertion easier. In addition, when the cap 4 is made of a transparent or translucent material, one of these long ribs 4f may be arranged in a position corresponding to directly below the clip portion 4b extending in the longitudinal direction. This allows the clip portion 4b and the opposing long rib 4f to be arranged on approximately the same plane passing through the central axis of the cap 4, creating an aesthetic impression.

The front end 4d of the cap body 4a is provided with a fitting portion 14 arranged on the central axis, two connection portions 15 connecting the end 4d and the fitting portion 14, and a support wall 16 arranged around the fitting portion 14 and the connection portions 15. In addition, the front end 4d of the cap body 4a is provided with a circular ventilation opening 4g around the central axis, but the ventilation opening 4g may be omitted.

The fitting portion 14 has a truncated cone shape with a larger diameter at the rear end and a smaller diameter toward the front end. The front end surface edge 14a of the fitting portion 14 is rounded and chamfered. The rear end surface edge 14b has a 90 degree or acute angle 14c. The shape of the fitting portion 14 is not limited to a truncated cone shape, but may be a sphere, a cylinder, a polygonal truncated pyramid, etc.

The connection parts 15 are two columnar members that extend from the inner wall of the ventilation opening 4g toward the front of the cap 4, and are arranged symmetrically with respect to the central axis of the cap 4. The fitting part 14 is supported by the connection parts 15 so that its disk-shaped surface is perpendicular to the central axis of the cap 4. The fitting part 14 is also supported by the connection parts 15 near its edge on its rear end surface. As is clear from FIG. 3, the connection parts 15 do not extend along the central axis, but extend at a slight angle toward the central axis as they move forward. The cap body 4a has a ventilation opening and the two connection parts 15 are spaced apart, allowing air to flow from the front end to the rear end of the cap body 4a.

In this embodiment, the cap body 4a, the fitting portion 14, and the connection portion 15 are integrally formed, but they may be formed separately. Also, in this embodiment, there are two connection portions 15, but there may be one or three or more. When there is one connection portion 15, it is connected near the center of the opposing surface of the fitting portion 14. Also, when the ventilation opening 4g is not provided at the front end portion 4d of the cap body 4a, it is configured to extend forward from the front end portion 4d of the cap body 4a.

The support wall 16 is a tubular member arranged around the fitting portion 14 and the connection portion 15. The outer peripheral surface of the support wall 16 is formed flush with the outer peripheral surface of the cap body 4a. In this embodiment, the cap body 4a and the support wall 16 are formed integrally, but they may be formed separately. The support wall 16 has an inner peripheral surface 16a into which the insertion portion 2a of the erasing member 2 fits, as described below.

Next, the structure of the erasing member 2 will be described with reference to Figures 5 to 7. Figure 5 is a perspective view of the erasing member 2 of the writing instrument 1 shown in Figure 1, Figure 6 is another perspective view of the erasing member 2 of the writing instrument 1 shown in Figure 1, and Figure 7 is a vertical cross-sectional view of the erasing member 2 shown in Figure 5.

The erasing member 2 has an insertion portion 2a that is inserted between the support walls 16 of the cap body 4a and surrounded by the insertion portion 2a, an erasing portion 2b that is exposed to the outside when the erasing member 2 is attached to the cap and is used to scratch paper surfaces, and a fitting hole 2c that extends in the axial direction and penetrates the insertion portion 2a and the erasing portion 2b. The insertion portion 2a and the erasing portion 2b may be formed integrally. Examples of materials that form the erasing member 2 include rubber materials such as silicone rubber, nitrile rubber, ethylene propylene rubber, and ethylene propylene diene rubber, and thermoplastic elastomers such as styrene-based elastomers, olefin-based elastomers, and polyester-based elastomers, rubber elastic materials, mixtures of two or more types of elastic materials, mixtures of rubber elastic materials and synthetic resins, commercially available erasers, etc.

The insertion portion 2a is generally cylindrical in shape corresponding to the shape of the inner peripheral surface 16a of the support wall 16 of the cap body 4a, and has an annular engagement protrusion 2d on its side in the circumferential direction. The engagement protrusion 2d abuts against the inner peripheral surface 16a of the support wall 16 to hold the erasing member 2 in place so that it does not rattle when attached to the cap 4. Note that instead of the annular engagement protrusion 2d, multiple protrusions may be formed in the circumferential direction. Also, if rattling of the erasing member 2 can be prevented by other means, it is not necessary to have the engagement protrusion 2d.

A flat portion 2e may be provided along the axial direction on a portion of the side of the insertion portion 2a. When the eraser 2 is formed by injection molding, the flat portion 2e can be used as the gate position during molding. As a result, even if a gate residue occurs on the flat portion 2e after molding, it is possible to prevent the gate residue from contacting the inner surface because there is a clearance between the surface of the flat portion 2e and the inner surface 16a of the support wall 16 of the cap body 4a. In addition, as described below, by providing a protrusion corresponding to the inner surface 16a of the support wall 16, it is possible to position the eraser 2 in a specified direction during installation, and rotation of the eraser 2 can be prevented after installation.

The erasing portion 2b has a truncated cone shape with a larger diameter at the rear end and a smaller diameter toward the front end. The edge of the front end surface of the erasing portion 2b is rounded and chamfered. The rear end portion of the erasing portion 2b has a larger diameter than the insertion portion 2a, and therefore forms a stepped jaw portion 2f between the insertion portion 2a and the rear end surface. When the erasing member 2 is attached to the cap, the rear end surface of the jaw portion 2f abuts against the front end surface 16b of the support wall 16.

The fitting hole 2c extends in the axial direction and penetrates the insertion portion 2a and the erasing portion 2b. The fitting hole 2c receives the fitting portion 14 and the connection portion 15 of the cap 4 when the erasing member 2 is attached to the cap 4. The fitting hole 2c is divided into a tapered portion 2g, a small diameter portion 2h, and a large diameter portion 2i, in that order from the rear end portion into which the fitting portion 14 is inserted, i.e., the entrance portion. The tapered portion 2g is tapered from the rear end portion of the fitting hole 2c toward the front, i.e., from the entrance portion toward the back. The inner diameter of the front end of the tapered portion 2g and the inner diameter of the rear end of the small diameter portion 2h are set to be approximately equal. The boundary between the small diameter portion 2h and the large diameter portion 2i is stepped, forming a locking portion 2j that prevents the fitting portion 14 from coming off, as described later. The small diameter portion 2h may be omitted.

In this embodiment, the fitting hole 2c is a through hole, so even if the erasing member 2 comes off the cap after product shipment and is accidentally swallowed by a small child, safety can be ensured without blocking the airway.

Next, the attachment of the erasing member 2 and the cap 4 will be described with reference to Figs. 8 to 14. Fig. 8 is a perspective view of the cap 4 to which the erasing member 2 of the writing instrument 1 shown in Fig. 1 is attached, Fig. 9 is a side view of the cap 4 shown in Fig. 8, Fig. 10 is a vertical cross-sectional view of the cap 4 shown in Fig. 8 taken along line X-X in Fig. 9, Fig. 11 is another vertical cross-sectional view of the cap 4 shown in Fig. 8, Fig. 12 is a cross-sectional view of the cap 4 shown in Fig. 8 taken along line Y-Y in Fig. 9, Fig. 13 is a cross-sectional view of the cap 4 shown in Fig. 8 taken along line Z-Z in Fig. 9, and Fig. 14 is an enlarged cross-sectional view showing the attachment portion of the erasing member 2 of the writing instrument 1 shown in Fig. 1 and the cap 4. Fig. 11 is a cross-sectional view at a position rotated 90 degrees around the central axis from the cross-sectional view shown in Fig. 10.

When the erasing member 2 is inserted between the support walls 16 of the cap body 4a, the fitting portion 14 is inserted into the fitting hole 2c of the erasing member 2, and the outer peripheral surface of the insertion portion 2a of the erasing member 2 is guided along the inner peripheral surface of the support wall 16. The fitting portion 14 passes through the tapered portion 2g and small diameter portion 2h of the fitting hole 2c, and passes over the locking portion 2j. When the rear end surface of the jaw portion 2f of the erasing member 2 abuts against the front end surface 16b of the support wall 16, the installation of the erasing member 2 is complete.

The maximum outer diameter of the fitting portion 14 is set to be larger than the minimum inner diameter of the tapered portion 2g of the fitting hole 2c, i.e., the inner diameter of the small diameter portion 2h, and equal to or smaller than the inner diameter of the large diameter portion 2i. Therefore, when the fitting portion 14 passes through the tapered portion 2g and small diameter portion 2h of the fitting hole 2c, the fitting portion 14 or the insertion portion 2a of the erasing member 2 undergoes elastic deformation.

The front end edge 14a of the fitting portion 14 is rounded and the entrance portion when inserted into the fitting hole 2c is a tapered portion 2g, so that the fitting portion 14 can be smoothly inserted into the fitting hole 2c. Furthermore, while the fitting portion 14 is being inserted into the fitting hole 2c, only the outer peripheral surface 14d of the fitting portion 14 moves in the fitting hole 2c while abutting against the inner peripheral surface 2k of the fitting hole 2c. In other words, the pressure force required for insertion is largely due to the friction force between the outer peripheral surface 14d of the fitting portion 14 and the inner peripheral surface 2k of the fitting hole 2c, but since the contact area between them is approximately constant, the pressure force required during insertion is also approximately constant. Therefore, it is possible to easily attach the eraser 2 to the cap.

Here, the inner diameter of the tapered portion 2g and the small diameter portion 2h of the fitting hole 2c is set so that the two connecting portions 15 are included or abutted when the installation is completed. That is, as described above, the two connecting portions 15 extend at an incline toward the central axis as they go forward, but this inclination is set to be equal to or greater than the inclination of the tapered portion 2g of the fitting hole 2c. Therefore, the connecting portions 15 do not abut against the inner peripheral surface 2k of the fitting hole 2c during installation of the erasing member 2. On the other hand, by setting the inclinations of both to be equal, the two connecting portions 15 can be inscribed on the inner peripheral surface of the tapered portion 2g when installation is completed. This makes it possible to achieve a strong installation without rattling the erasing member 2.

As is clear from the relationship between the connection portion 15 and the inner circumferential surface 2k of the fitting hole 2c, the insertion with a substantially constant contact area is achieved by the presence of a gap space 17 around the connection portion 15, which is formed because the fitting portion 14 is supported by the columnar connection portion 15. The gap space 17 is defined by the fitting portion 14, the connection portion 15, and the inner circumferential surface 2k of the fitting hole 2c of the erasing member 2. The presence of the gap space 17 reduces frictional resistance during attachment of the erasing member 2 to the cap, making attachment easier.

When the attachment is complete, the fitting portion 14 is slightly spaced in the axial direction from the stepped locking portion 2j provided in the fitting hole 2c of the erasing member 2. Similarly, the rear end surface of the insertion portion 2a of the erasing member 2 is also slightly spaced in the axial direction from the front end portion 4d of the cap body 4a. The engaging protrusion 2d provided on the side surface of the insertion portion 2a of the erasing member 2 elastically deforms to engage with the inner surface 16a of the support wall 16, making it difficult for the erasing member 2 to come off. Furthermore, in order to more reliably engage the engaging protrusion 2d with the inner surface 16a of the support wall 16, a recess 16c of a shape corresponding to the engaging protrusion may be provided on the inner surface of the support wall 16 at a position corresponding to the engaging protrusion 2d after attachment is complete.

When installation is complete, the elastic deformation of the fitting portion 14 or the insertion portion 2a of the erasing member 2 at the time of installation is restored. Therefore, when attempting to pull out the erasing member 2 from the cap 4 for the purpose of replacing the erasing member 2, the front end surface of the locking portion 2j of the erasing member 2 engages with the corner portion 14c on the rear end surface of the fitting portion 14, preventing this. Therefore, in order to pull out the erasing member 2 from the cap 4, it is necessary to apply a stronger force. This causes the locking portion 2j or the corner portion 14c to elastically deform, releasing the engagement, and it becomes possible to pull out the erasing member 2 from the cap 4.

The pulling force required to pull the erasing member 2 out of the cap 4 is preferably designed to be greater than the press-fitting force required to attach the erasing member 2 to the cap 4. This can be achieved, for example, by adjusting the inclination or minimum inner diameter of the tapered portion 2g of the fitting hole 2c, the maximum outer diameter of the fitting portion 14, etc.

The fitting hole 2c of the eraser 2 may be configured to have only the tapered portion 2g, without the small diameter portion 2h and the large diameter portion 2i, i.e., without the locking portion 2j. In this case, the fitting portion 14 engages with the frictional resistance between its outer circumferential surface 14d and the inner circumferential surface of the tapered portion 2g of the fitting hole 2c.

Here, the writing instrument 1 according to one embodiment of the present invention shown in FIG. 1 uses thermochromic ink as the ink. Thermochromic ink refers to ink that maintains a certain color (first color) at room temperature (e.g., 25°C), changes to another color (second color) when heated to a certain temperature (e.g., 60°C), and then returns to the original color (first color) when cooled to a certain temperature (e.g., -5°C). In the writing instrument 1 using thermochromic ink, the second color is made colorless, and the heating of the lines drawn in the first color (e.g., red) to make them colorless is referred to as "erasing" here. Therefore, in this embodiment, the eraser 2 rubs against the paper surface on which the lines are drawn, generating frictional heat, which changes the drawn lines to colorless, i.e., erases them. Of course, the second color may be a color other than colorless.

In the present invention, "erasing" refers to adsorbing or scraping off written lines, characters, etc. with an erasing member 2 such as an eraser, in addition to when the above-mentioned thermochromic ink is used. Therefore, the above and following aspects of the present invention can be applied to any writing implement that erases written lines with an erasing member 2.

Below, we will explain a writing instrument according to another aspect of the present invention. The writing instrument body is the same as the above-mentioned aspect, so we will omit the explanation and will explain the differences from the above-mentioned aspect.

15 is a perspective view of a cap 24 of a different embodiment from the cap 4 of the writing instrument 1 shown in FIG. 1, and FIG. 16 is a vertical cross-sectional view of the cap 24 shown in FIG. 15. The cap 24 shown in FIG. 15 and FIG. 16 differs from the cap 4 shown in FIG. 2 to FIG. 4 only in that it has a positioning protrusion 24h. The positioning protrusion 24h has a shape complementary to the flat portion 2e provided on the insertion portion 2a of the erasing member 2 when the erasing member 2 is attached to the cap 24. By having the positioning protrusion 24h on the cap 24, it is possible to position the erasing member 2 in a predetermined direction when attached, and the erasing member 2 can be prevented from rotating after attachment. When the cap 24 is made of a transparent or translucent material, it is preferable that the positioning protrusion 24h is provided on the side where the clip portion 4b is located on the inner peripheral surface 16a of the support wall 16, because this creates an aesthetic feeling in terms of the alignment with the clip portion 4b.

Figure 17 is a perspective view of a cap 24 to which an erasing member 22 of a different embodiment from the erasing member 2 of the writing instrument shown in Figure 1 is attached, Figure 18 is a vertical cross-sectional view of the cap 24 shown in Figure 17, and Figure 19 is a vertical cross-sectional view of the erasing member 22 shown in Figure 17.

In this embodiment, the cap 24 is as shown in Figs. 15 and 16. The erasing member 22 differs from the erasing member 2 shown in Figs. 5 to 7 in that the fitting hole 22c does not penetrate to the erasing portion 22b. That is, although the fitting hole 22c is depicted in a simplified manner in the figures, it has at least a tapered portion, a locking portion, and a large diameter portion within the insertion portion 22a, and the axial length of the large diameter portion is set to a length that receives the fitting portion 14 and the connection portion 15 of the cap. As mentioned above, the fitting hole 22c may have only a tapered portion.

The front end surface of the erasing portion 22b is provided with a concave recess 22m. By providing the recess 22m on the front end surface of the erasing portion 22b, it is possible to erase small areas using the edge of the recess 22m. In addition, by holding the erasing member 22 perpendicular to the paper surface on which the lines are drawn, frictional resistance is reduced compared to when the front end surface of the erasing portion is formed into a convex curved surface, making it possible to erase a wide area smoothly.

Figure 20 is a perspective view of a cap 24 to which an erasing member 32 of yet another embodiment different from the erasing member 2 of the writing instrument shown in Figure 1 is attached, Figure 21 is a perspective view of the erasing member 32 shown in Figure 20, and Figure 22 is a front view of the erasing member 32 shown in Figure 20.

In this embodiment, the cap 24 is as shown in Figs. 15 and 16. The eraser 32 is the same as the eraser 2 shown in Figs. 5 to 7 in terms of the insertion portion 2a and the fitting hole 2c, and differs only in the outer shape of the eraser 32b. The eraser 32b has a cross-sectional shape that is circular at the rear end face, but gradually changes to an elliptical shape with a ratio of the major axis to the minor axis gradually increasing from the rear end face to the front end face. The length of the major axis of the ellipse at the front end face of the eraser 32b is shorter than the diameter of the circle at the rear end face of the eraser 32b. By making the cross-sectional shape of the eraser 32b elliptical, when erasing a drawn line, it is possible to realize different erasure widths, i.e., areas that can be rubbed at once, depending on whether the major axis direction is parallel to the paper surface, the minor axis direction is parallel to the paper surface, or somewhere in between.

Figure 23 is a perspective view of a cap 24 to which an erasing member 42 of yet another embodiment different from the erasing member 2 of the writing instrument shown in Figure 1 is attached, Figure 24 is a perspective view of the erasing member 42 shown in Figure 23, and Figure 25 is a front view of the erasing member 42 shown in Figure 23.

In this embodiment, the cap 24 is as shown in Figs. 15 and 16. The eraser 42 is the same as the eraser 2 shown in Figs. 5 to 7 in terms of the insertion portion 2a and the fitting hole 2c, and is different only in the outer shape of the eraser 42b. The cross-sectional shape of the eraser 42b is circular at the rear end face, but hexagonal at the front end face, and has an outer shape that gradually changes from circular to hexagonal from the rear end face to the front end face. The hexagonal shape of the front end face of the eraser 42b is rounded at its corners, and preferably, one side of the hexagon is formed so as to be parallel to the flat portion 2e of the insert portion 2a. By having the front end face of the eraser 2b have a hexagonal shape, it is possible to erase minute places using the side portion 42n and the corner portion 42o. The shape of the front end face of the eraser 42b is not limited to a hexagon, and may be a triangle, a rectangle, or another polygon.

Figure 26 is a perspective view of a cap 24 to which an erasing member 52 of yet another embodiment different from the erasing member 2 of the writing instrument shown in Figure 1 is attached, Figure 27 is a perspective view of the erasing member 52 shown in Figure 26, and Figure 28 is a front view of the erasing member 52 shown in Figure 26.

In this embodiment, the cap 24 is as shown in Figs. 15 and 16. The eraser 52 is the same as the eraser 2 shown in Figs. 5 to 7 in terms of the insertion portion 2a and the fitting hole 2c, and differs only in the external shape of the eraser 52b. When considering the eraser 52b as a half body split vertically, the first half 52p has a truncated cone shape, and the second half 52q has a truncated hexagonal pyramid shape. A flat portion 2e, which is positioned by a positioning protrusion 24h of the cap body 4a, is provided on the first half 52p side of the insert portion 2a so that the first half is positioned on the clip portion 4b side of the cap 24.

By placing the first half 52p on the clip portion 4b side of the cap, the hexagonal pyramid-shaped surface of the second half 52q becomes easier to use. That is, when a user holds the cap 24 to perform an erasing operation, they usually place their index finger and thumb on either side of the clip portion 4b to avoid the clip portion 4b, and grip the cap 24 by placing their middle finger on the part of the outer periphery of the cap body 4a opposite the side where the clip portion 4b is located. Therefore, in this gripping state, the hexagonal pyramid-shaped surface of the second half 52q faces the paper.

The first half 52p has the same shape as the erasing section 2b shown in Figures 5 to 7. The second half 52q is a half-body with a hexagonal pyramid shape and has three flat surfaces 52r. Therefore, erasing with the first half 52p of the erasing section 52b makes it possible to erase on a narrow surface. On the other hand, when erasing with the second half 52q of the erasing section 52b, erasing on a wider surface is possible by using each flat surface 52r than when using the first half 52p. In addition, erasing on a smaller area is possible by using the peaks 52s, which are the connecting parts of each flat surface, or the connecting parts 52t between the peaks and the front end face.

Figure 29 is a perspective view of a cap 24 to which an erasing member 62 of a different embodiment from the erasing member 2 of the writing instrument shown in Figure 1 is attached, Figure 30 is a perspective view of the erasing member 62 shown in Figure 29, and Figure 31 is a front view of the erasing member 62 shown in Figure 29.

In this embodiment, the cap 24 is as shown in Figs. 15 and 16. The eraser 62 is the same as the eraser 2 shown in Figs. 5 to 7 in terms of the insertion portion 2a and the fitting hole 2c, and differs only in the outer shape of the eraser 62b. The eraser 62b is configured by replacing both sides of the second half 52q shown in Figs. 26 to 28 with the truncated cone shape of the first half 52p. Therefore, the eraser 62b consists of a truncated cone-shaped portion 62u and a truncated hexagonal pyramid-shaped portion 62v. A flat portion 2e, which is positioned by a positioning protrusion 24h of the cap body 4a, is provided on the truncated cone-shaped portion 62u side of the insert portion 2a so that the truncated cone-shaped portion 62u is positioned on the clip portion 4b side of the cap 24.

By placing the truncated cone-shaped portion 62u on the clip portion 4b side of the cap 24, the surface of the truncated hexagonal pyramid-shaped portion 62v can be easily used. That is, when a user normally holds the cap 24 to perform an erasing operation, they place their index finger and thumb on either side of the clip portion 4b to avoid it, and hold the cap 24 by placing their middle finger on the part of the outer surface of the cap body 4a opposite the side where the clip portion 4b is located. Therefore, when held in this state, the surface of the truncated hexagonal pyramid-shaped portion 62v faces the paper.

By erasing with the truncated cone-shaped portion 62u of the erasing portion 62b, erasing over a narrow surface becomes possible. On the other hand, when erasing with the truncated hexagonal pyramid-shaped portion 62v of the erasing portion 62b, erasing over a wider surface becomes possible by using one surface than when the truncated cone-shaped portion 62u is used. In addition, by using the peaks 62w, which are the connecting portions of the surfaces, or the connecting portion 62x between the peaks 62w and the front end surface, erasing of smaller areas becomes possible.

In the above embodiment of the erasing member of the present invention, the erasing member is attached to the front end of the cap, but it can also be attached to the rear end of the writing instrument body in the same way.

Figure 32 is a vertical cross-sectional view of a writing instrument 100 according to a second embodiment having an erasing member 2 according to one aspect of the present invention. The writing instrument 100 is a ballpoint pen type writing instrument, and has a writing instrument body 3 having a refill 5 and a cylindrically extending barrel 6, and a cap 104. The barrel 6 has a cylindrical front barrel 7 and a rear barrel 8 whose front end is screwed into the rear end of the front barrel 7. The writing instrument 100 according to this embodiment differs from the writing instrument 1 according to the first embodiment described above only in the outer shape of the cap, particularly the shape of the clip part. Therefore, the following description will particularly describe the clip part, and other parts will be omitted. Note that the cap 104 can be configured to be able to attach an erasing member attached to the cap 4 shown in Figure 4, for example, or to be able to attach an erasing member attached to the cap 24 shown in Figure 15, for example.

Figure 33 is a perspective view of the cap 104 of the writing instrument 100 shown in Figure 32, Figure 34 is a plan view of the cap 104 shown in Figure 33, Figure 35 is a side view of the cap 104 shown in Figure 33, Figure 36 is a vertical cross-sectional view of the cap 104 shown in Figure 33, and Figure 37 is a cross-sectional view of the cap 104 shown in Figure 33 taken along line S-S in Figure 35.

The cap 104 has a cap body 104a, a clip portion 104b, and, in this embodiment, an erasing member 2. The cap body 104a is a cylindrical member, and the clip portion 104b is integrally provided on its side via a connection portion 104c. The clip portion 104b is configured to have elasticity so that it can hold documents, clothes, and other items between the cap body 104a and the clip portion 104b. Therefore, examples of materials for forming the cap body 104a and the clip portion 104b include synthetic resins such as polycarbonate and acrylonitrile butadiene styrene. As mentioned above, it is desirable to form them from a material harder than the tip shaft 7.

The cap 104 is characterized in that the clip portion 104b is a generally rectangular plate-like member that extends in the axial direction over the entire length of the clip body 104a. As shown in FIG. 34, the rear end surface of the clip portion 104b is curved to improve the feel. In addition, a guide surface 104d, which is a flat surface perpendicular to the central axis, is formed in the center of the front end surface of the clip portion 104b, and the front end surfaces on both sides of the guide surface 104d are curved like the rear end surface. Each edge of the clip portion 104b is chamfered. Note that the guide surface 104d does not have to be perpendicular to the central axis. For example, as will be described later with reference to FIG. 38, it may be an inclined surface that matches the paper surface that faces when erasing.

As is clear from the plan view of FIG. 34, the width W of the clip portion 104b is approximately the same as the diameter of the cylindrical cap body 104a. Therefore, from the user's viewpoint, the cap body 104a is almost completely hidden by the clip portion 104b, and only the clip portion 104b and the erasing member 2 are visible. That is, compared to a conventional clip portion, for example, the clip portion 4b of the cap 4 shown in FIG. 2, the clip portion 104b of the cap 104 has a wide, extensive, and smooth surface. Therefore, by applying decoration such as transfer printing to the surface, the design can be improved and the appeal to users can be increased. In addition, by attaching a rubber elastic material such as rubber or elastomer to the above surface, an erasing surface wider than the erasing member 2 is formed, making it possible to use different areas to be erased.

The connection portion 104c that connects the cap body 104a and the clip portion 104b has a T-shaped cross section as shown in FIG. 37. This increases the strength of the clip portion 104b against circumferential forces (the vertical direction in FIG. 37). Therefore, even if a circumferential force is applied to the clip portion 104b during use by a user, damage to the connection portion 104c is prevented.

Figure 38 is a diagram showing the use state of the cap 104 to which the erasing member 2 of the writing instrument 100 shown in Figure 32 is attached during erasing. As shown in Figure 38, when erasing, the flat guide surface 104d of the clip portion 104b is pressed against the paper surface while sliding the cap 104 along the guide surface 104d, thereby enabling erasure of handwriting in a fixed width. At this time, if the cap 104 is slid while pressing the guide surface 104d of the clip portion 104b against a guide member such as a ruler J, a more stable erasing operation is possible, and erasing of a long range with a fixed width can be easily performed. Furthermore, by sliding the cap 104 while pressing the guide surface 104d of the clip portion 104b against the paper surface and abutting the wide surface of 104b against the slope Ja provided on the ruler J, an even more stable erasing operation is possible.

In addition, by adjusting the shape of the erasing member 2, the axial position of the clip portion 104b relative to the cap body 104a, the shape of the guide surface 104d, etc., it is possible to adjust the angle A between the paper surface and the central axis of the writing instrument 100 during the erasing operation. It is desirable for this angle A to be in the range of 40 to 80 degrees.

In addition to the above-mentioned effects, because the width W of the clip portion 104b and the diameter of the cap body 104a are approximately the same, for example, when the writing instrument 100 is placed on a desk or the like with the wide flat surface of the clip portion 104b facing up, the writing instrument 100 rotates and the side of the clip portion 104b comes into contact with the desk or the like, so that the writing instrument 100 can be maintained in a sideways position. This has the effect of making it easier to grip the barrel 6 when picking up the writing instrument 100. It is also possible to always prevent the writing instrument 100 from rolling.

Furthermore, by extending the clip portion 104b to the center of gravity of the writing instrument and having the cap 104 have the clip portion 104b with the above-mentioned structure, for example, when the writing instrument 100 is placed on a desk or the like with the wide flat surface of the clip portion 104b facing down, the rear end of the writing instrument 100 does not touch the desk and can be stabilized in a floating state. This has the effect of making it easier to grip the barrel 6 when picking up the writing instrument 100.

The structure of the clip portion 104b described in this embodiment can be applied not only to the cap, but also to the front and rear barrels.

Reference Signs List 1 Writing implement 2 Erasing member 2c Fitting hole 3 Writing implement body 4 Cap 14 Fitting portion 15 Connection portion 16 Support wall 17 Gap space

Claims (1)

A thermochromic writing instrument comprising: a barrel containing thermochromic ink therein and having a writing section at its front end from which the thermochromic ink can be ejected; and a cap removably attached to the writing section side of the barrel, the cap being provided with an erasing member, the erasing member rubbing handwriting of the thermochromic ink with the erasing member, and capable of thermochromically changing the color of the handwriting by the frictional heat generated at the time,
A clip portion is integrally provided on a side surface of the cap via a connecting portion,
The clip portion is a substantially rectangular plate-like member extending in an axial direction,
The width of the clip portion and the diameter of the cap are substantially the same, and the clip portion extends to the center of gravity of the thermochromic writing instrument,
A thermochromic writing instrument in which the outer surface of the cap narrows toward the front, the center of gravity of the thermochromic writing instrument is located inside the cap when the cap is attached to the writing portion side of the barrel, and when the thermochromic writing instrument is placed on a horizontal support surface with the cap attached to the writing portion side of the barrel, the outer surface of the clip portion comes into contact with the horizontal support surface, and the outer surface and rear end of the barrel rearward of the cap are not in contact with the horizontal support surface.

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