Fountain pen and method for producing pen body of fountain pen

Abstract

To provide a fountain pen capable of preventing a pen body after pressing from becoming stuck in a mold even when a metal material with high spring properties is used as the pen body, and a method for producing a pen body of a fountain pen.SOLUTION: A fountain pen comprises a pen core extending in the front-and-back direction along a central axis, a curved, plate-shaped pen body 2 disposed on an upper portion of the outer circumferential surface of the pen core, and a shaft cylinder having a front opening into which the rear portions of the pen core and the pen body 2 are inserted, and the pen body 2 includes a writing unit 21 located at the more front side than the shaft cylinder, a holding unit 22 disposed behind the writing unit 21, inserted into the front opening, and held between the inner circumferential surface of the shaft cylinder and the outer circumferential surface of the pen core, and a recess 2e disposed in the holding unit 22 and recessed inward in the left-right direction from the outer edge of the pen body 2 in the left-right direction.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a fountain pen and a method for manufacturing the pen body of a fountain pen.

Background Art

[0002] As a conventional fountain pen, for example, the one disclosed in Patent Document 1 is known. The fountain pen described in Patent Document 1 has a structure in which a pen body and a pen core are superposed and inserted into the front opening of a shaft cylinder. The pen body is plate-shaped and is curved in an arc shape in a cross section so as to follow the inner peripheral surface of the shaft cylinder and the outer peripheral surface of the pen core. Further, the pen body is formed of a metal such as 14K gold or 18K gold having a soft material.

[0003] In addition, two rectangular window portions are formed in the insertion portion of the pen body that is inserted into the front opening of the shaft cylinder. There is a burr portion that projects on the lower side (back side) of the pen body in terms of processing at the peripheral edge of the window portion. When the burr portion catches on the surface of the pen core, the removal and rotation of the pen body are prevented.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In this type of fountain pen, attempts have been made to use a plate-shaped metal material other than gold as the pen body. By using a material with high springiness, for example, as the metal of the pen body, a good writing feeling similar to that of gold can be obtained.

[0006] However, a metal material with high spring properties is likely to have a large springback after press working for curving the pen body. If the springback is large, the processed pen body will get stuck in the female mold (forming die) of the mold used for the above press working, and there will be a problem that it cannot be released even when extruded with a discharge pin or the like provided in the female mold.

[0007] An object of the present invention is to provide a fountain pen and a method for manufacturing a pen body of a fountain pen that can prevent the problem that the pen body after press working gets stuck in the mold even when a metal material with high spring properties is used as the pen body.

Means for Solving the Problem

[0008] In order to solve the above problems, the present invention provides the following means.

[0009] 〔Aspect 1 of the Present Invention〕 A fountain pen comprising: a pen core extending in the front-rear direction along a central axis; a curved plate-shaped pen body disposed on an upper portion of the outer peripheral surface of the pen core; and a shaft cylinder having a front opening into which the rear portions of the pen core and the pen body are inserted, wherein the pen body has a writing portion disposed in front of the shaft cylinder, a holding portion disposed behind the writing portion, inserted into the front opening, and held between the inner peripheral surface of the shaft cylinder and the outer peripheral surface of the pen core, and a concave portion disposed in the holding portion and recessed inward in the left-right direction from the left-right outer edge of the pen body.

[0010] During the manufacture of the fountain pen, a pen body having a curved shape is obtained by press working a blank punched out from a plate-shaped metal material between molds (male mold and female mold). The holding portion of the pen body is a portion sandwiched between the inner peripheral surface of the shaft cylinder and the outer peripheral surface of the pen core, and has a curved shape (arc shape) with a smaller radius of curvature in a cross-sectional view perpendicular to the central axis than the writing portion exposed outside the shaft cylinder.

[0011] In a conventional fountain pen, when a highly springy metal material is used for the pen body, among the pen body, in particular, the holding part with a small radius of curvature is likely to fit into the female mold due to springback after press working, and it has been difficult to release from the mold.

[0012] On the other hand, in the fountain pen of the present invention, a concave part is formed in the holding part of the pen body, and the concave part is recessed inward from the outer edge in the left - right direction of the pen body. Due to such a concave part, when the blank is press - worked, it is suppressed that the vicinity of the outer edge in the left - right direction of the pen body catches on the inner surface of the female mold.

[0013] More specifically, even if the pen body springs back greatly after press working by using a highly springy metal material, the contact resistance and catching between the holding part and the inner surface of the female mold are suppressed by the concave parts provided at the outer ends in the left - right direction of the holding part. Therefore, the holding part is suppressed from fitting into the female mold. For this reason, the pen body can be press - worked efficiently. Also, the quality of the manufactured pen body is maintained well.

[0014] Moreover, since the concave part is formed in the holding part inserted into the front - side opening of the shaft cylinder, it is not exposed to the outside of the fountain pen. Therefore, while obtaining the excellent effects described above by the concave part, the influence on the appearance design of the fountain pen is suppressed.

[0015] From the above, according to the present invention, even when a highly springy metal material is used for the pen body, it is possible to prevent the problem that the pen body after press working fits into the mold. As a result, a high - quality fountain pen can be manufactured efficiently, and productivity can be increased.

[0016] The reason for forming the pen body into a curved plate shape is as follows. That is, for example, it is also possible to assemble with the pen core and use it as a fountain pen in a shape close to that of a flat blank with little curvature of the pen body. However, in this case, when a writing pressure load is applied to the pen body during writing, the pen tip and cutting of the pen body do not spread, and it does not become the line width with a unique cadence peculiar to a fountain pen.

[0017] On the other hand, when the pen body is in the shape of a curved plate as in the present invention, during writing, the pen tip and the nib of the pen body can be moderately spread, resulting in a line width with a unique cadence characteristic of a fountain pen. That is, the fountain pen of the present invention realizes a characteristic and cadenced line width while achieving the excellent effects described above.

[0018] 〔Aspect 2 of the present invention〕 The pen body has a pair of shoulders disposed in the writing part and protruding outward in the left - right direction, and a pair of first protrusions disposed in the holding part and protruding outward in the left - right direction. The recess is disposed between the shoulders and the first protrusions in the front - rear direction. The fountain pen according to Aspect 1.

[0019] In this case, the pen body is provided with four protruding parts (a pair of shoulders and a pair of first protrusions) spaced apart from each other in the front - rear direction and the left - right direction. When setting the blank for the pen body in the mold and performing press working, the above four protruding parts can be used as positioning means for the mold. Thereby, the accuracy of the press working is stably improved.

[0020] And in the above configuration, the recess is disposed between the shoulders and the first protrusions in the front - rear direction. Thereby, the above - described effect of preventing the fitting into the female mold by the recess is more stably achieved.

[0021] 〔Aspect 3 of the present invention〕 The pen body has a pair of second protrusions disposed between the pair of shoulders and the pair of first protrusions in the front - rear direction and protruding outward in the left - right direction. The fountain pen according to Aspect 2.

[0022] In this case, the pen body is provided with six protruding portions (a pair of shoulders, a pair of first protrusions, and a pair of second protrusions) that are spaced apart from each other in the front-rear direction and the left-right direction. When setting a blank that becomes the pen body in a mold and performing press working, the six protruding portions can be used as positioning means for the mold. Thereby, the accuracy of press working is more stably enhanced.

[0023] 〔Aspect 4 of the present invention〕 The pen body has a pen tip disposed at the front end of the writing portion and a main body portion that constitutes a portion of the pen body other than the pen tip. The main body portion is made of metal, has a Young's modulus of 230 GPa or less, and a 0.2% proof stress of 800 MPa or more. The fountain pen according to any one of Aspects 1 to 3.

[0024] Generally, the springback amount after press working of a metal material increases as the Young's modulus decreases, and also increases as the 0.2% proof stress (yield stress) increases. When the Young's modulus of the metal material constituting the main body portion of the pen body is set to 230 GPa or less and the 0.2% proof stress is set to 800 MPa or more as in the above configuration, the springback amount after press working tends to be large. Even when a metal material with such a large springback is used for the pen body, according to the present invention, by providing the concave portion, the fitting into the female mold can be stably suppressed. In particular, in the present invention, even when a metal material with a 0.2% proof stress of 850 MPa or more is used for the main body portion of the pen body, the fitting into the female mold due to springback can be stably suppressed. When using a metal having a yield point in the stress-strain diagram as the pen body, the above “0.2% proof stress” may be replaced with “upper yield point”.

[0025] 〔Aspect 5 of the present invention〕 The pen core has a convex portion that protrudes from the outer peripheral surface of the pen core and is disposed in the concave portion. The convex portion can be locked to the concave portion in the front-rear direction or the left-right direction. The fountain pen according to any one of Aspects 1 to 4.

[0026] In this case, the convex portion protruding from the outer peripheral surface of the pen core is locked to the concave portion of the pen body, thereby restricting the relative movement of the pen core and the pen body in the front-rear direction or the left-right direction. As a result, the pen body is prevented from coming off (moving forward), being pushed in (moving backward), and rotating around the central axis with respect to the pen core. According to the fountain pen of the present invention, since the attachment posture of the pen body with respect to the pen core is stable, a good writing feeling can be stably maintained.

[0027] 〔Aspect 6 of the present invention〕 The pen core has an ink groove extending in the front-rear direction, a plurality of comb-shaped grooves communicating with the ink groove and arranged side by side in the front-rear direction, and a concave ink reservoir portion arranged at a portion of the outer peripheral surface of the pen core located between the comb-shaped grooves adjacent to each other in the front-rear direction. The ink reservoir portion is arranged outside the convex portion in the left-right direction and adjacent to the convex portion. The fountain pen according to Aspect 5.

[0028] For example, when the internal pressure of the ink storage portion provided inside the fountain pen is increased higher than the external pressure due to a decrease in air pressure, a rise in temperature, etc., the ink overflowing from the ink storage portion is temporarily held in a plurality of comb-shaped grooves through the ink groove. According to the above configuration of the present invention, since the pen core further has an ink reservoir portion, the overflowing ink can be held by the plurality of comb-shaped grooves and the ink reservoir portion.

[0029] 〔Aspect 7 of the present invention〕 A method for manufacturing the pen body of the fountain pen according to Aspect 2, comprising a punching step of punching a plate-shaped metal material to form a blank, and a pressing step of forming the curved plate-shaped pen body by pressing the blank between a female mold and a male mold. In the pressing step, the pair of shoulders and the pair of first protrusions formed on the blank are used as positioning means for the female mold. A method for manufacturing the pen body of a fountain pen.

[0030] In the method for manufacturing the pen body of the fountain pen of the present invention, when setting a blank in a female mold (forming die) and performing press working, four protruding portions (a pair of shoulders and a pair of first protrusions) are used as positioning means for the female mold. Thereby, the accuracy of press working is stably enhanced.

[0031] And in the present invention, as described above, the recess is disposed between the shoulder and the first protrusion in the front-rear direction. By providing such a recess, even when a metal material having high springiness (a large springback amount) is used as the pen body, it is possible to prevent the pen body from fitting into the female mold after press working.

Advantages of the Invention

[0032] According to the fountain pen of the above aspect of the present invention and the method for manufacturing the pen body of the fountain pen, even when a metal material having high springiness is used as the pen body, it is possible to prevent the problem that the pen body after press working fits into the mold.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

BEST MODE FOR CARRYING OUT THE INVENTION

[0034] A fountain pen 10 according to an embodiment of the present invention and a method for manufacturing the pen body 2 of the fountain pen 10 will be described with reference to the drawings.

[0035] As shown in FIG. 1, the fountain pen 10 has a substantially cylindrical shape centered on the central axis C. The fountain pen 10 includes a substantially cylindrical pen core 1 extending along the central axis C, a plate-shaped pen body 2 disposed overlapping the pen core 1, a cylindrical shaft tube 3, a cylindrical ink storage portion (not shown) disposed inside the shaft tube 3 and storing ink, and a cylindrical cap (not shown). The pen core 1, the shaft tube 3, the ink storage portion, and the cap are coaxially arranged with the central axis C as a common axis. Note that the pen body 2 of the present embodiment may be referred to as a pen tip or a pen.

[0036] Here, the definition of the directions used in the present embodiment will be described. In the present embodiment, an XYZ orthogonal coordinate system (3D orthogonal coordinate system) is appropriately set in each figure, and each component will be described. The direction in which the central axis C of the fountain pen 10 extends, that is, the direction along the central axis C, is referred to as the front-rear direction. The pen body 2 and the ink storage portion housed inside the shaft tube 3 are arranged at different positions in the front-rear direction. Among the front-rear directions, the direction from the ink storage portion to the pen body 2 is referred to as the front side, and the direction from the pen body 2 to the ink storage portion is referred to as the rear side. In each figure, the front-rear direction corresponds to the Y-axis direction. The front side corresponds to the -Y side, and the rear side corresponds to the +Y side. Note that the front-rear direction may be referred to as the axial direction. In this case, the front side may be referred to as one side (or the other side) of the axial direction, and the rear side may be referred to as the other side (or one side) of the axial direction.

[0037] The direction perpendicular to the central axis C is called the radial direction. Among the radial directions, the direction approaching the central axis C is called the inner radial direction, and the direction away from the central axis C is called the outer radial direction. Also, the direction of orbiting around the central axis C is called the circumferential direction.

[0038] As shown in FIGS. 2 and 5 to 8, the pen body 2 is attached to the outer peripheral surface of the pen core 1 at a position (displaced position) radially away from the central axis C. Further, the pen body 2 has a slit-shaped cut 2a extending in the front-rear direction. In the present embodiment, among the radial directions, the direction in which an imaginary straight line (not shown) connecting the central axis C and the cut 2a extends as viewed from the front-rear direction is called the vertical direction. Among the vertical directions, the direction from the central axis C toward the cut 2a (pen body 2) is called the upper side, and the direction from the cut 2a (pen body 2) toward the central axis C is called the lower side. In each figure, the vertical direction corresponds to the Z-axis direction. The upper side corresponds to the +Z side, and the lower side corresponds to the -Z side.

[0039] Also, the direction perpendicular to the front-rear direction and the vertical direction is called the left-right direction. In each figure, the left-right direction corresponds to the X-axis direction. The left side corresponds to the +X side, and the right side corresponds to the -X side. Also, among the left-right directions, the direction approaching the central axis C is called the inner side (or central side) of the left-right direction, and the direction away from the central axis C is called the outer side of the left-right direction.

[0040] In the present embodiment, the front side, the rear side, the upper side, the lower side, the left side, and the right side are convenient names for explaining the relative positional relationship of each component. Therefore, the actual arrangement relationship and the like during the use of the fountain pen 10 are not limited by these names.

[0041] Each component of the fountain pen 10 will be described. As shown in FIG. 1, the shaft cylinder 3 has a cylindrical shape extending in the front-rear direction, specifically, a substantially cylindrical shape. The shaft cylinder 3 has a neck cylinder 31 disposed at the front end of the shaft cylinder 3 and a main body cylinder (not shown) disposed on the rear side of the neck cylinder 31 and detachably attached to the neck cylinder 31 by screwing or the like.

[0042] The front cylinder 31 has a front opening 31a that penetrates the front cylinder 31 in the front-rear direction. That is, the shaft cylinder 3 has a front opening 31a that opens on the front end face of the shaft cylinder 3 and extends in the front-rear direction. The front opening 31a is in the shape of a substantially circular hole centered on the central axis C. The rear portions of the pen core 1 and the pen body 2 are inserted into the front opening 31a.

[0043] Although not particularly shown, the ink storage portion is in the shape of a cylinder centered on the central axis C and extends in the front-rear direction. The ink storage portion is disposed behind the pen body 2 and the pen core 1. The ink storage portion has, for example, a transparent peripheral wall, and the user can visually recognize the color and remaining amount of the ink stored inside from the outside of the ink storage portion. Also, when the remaining amount of ink in the ink storage portion decreases, the user can appropriately replenish the ink using a converter or the like.

[0044] As shown in FIG. 2, the pen body 2 is in the shape of a curved plate and is disposed on the upper portion of the outer peripheral surface of the pen core 1. The pen body 2 extends in the front-rear direction. The front end portion of the pen body 2 protrudes forward of the front end portion of the pen core 1. As shown in FIG. 4, the pen body 2 has a mirror-symmetric shape with respect to a virtual plane VS (a virtual plane VS that includes the central axis C in the plane) that extends in a direction perpendicular to the left-right direction (plane direction) passing through the center of the pen body 2 in the left-right direction. In other words, the pen body 2 has a left-right symmetric shape.

[0045] As shown in FIGS. 6 to 8, the pen body 2 is a curved plate that extends in the circumferential direction around the central axis C. The plate thickness dimension of the pen body 2 is, for example, 0.1 mm or more and 0.4 mm or less, and in this embodiment, it is about 0.2 mm.

[0046] As shown in Fig. 1, the pen body 2 has a writing portion 21 disposed on the front side of the neck cylinder 31 (shaft cylinder 3), and a holding portion 22 disposed on the rear side of the writing portion 21, inserted into the front opening 31a, and held between the inner peripheral surface of the neck cylinder 31 (shaft cylinder 3) and the outer peripheral surface of the pen core 1. The writing portion 21 and the holding portion 22 are integrally formed. Further, the connecting portion 23 where the writing portion 21 and the holding portion 22 are connected is disposed at the same position as the front end face of the neck cylinder 31 in the front-rear direction. Since the connecting portion 23 is also the boundary between the writing portion 21 and the holding portion 22, it may be referred to as the boundary portion.

[0047] As shown in Fig. 8, in a cross-sectional view perpendicular to the central axis C, the holding portion 22 extends in an arc shape centered on the central axis C. That is, the holding portion 22 extends along the circumferential direction. The radius of curvature r of the holding portion 22 is constant over the entire circumferential direction of the holding portion 22. The center Cr of the radius of curvature r of the holding portion 22 coincides with the central axis C of the fountain pen 10. As shown in Figs. 6 to 8, in a cross-sectional view perpendicular to the central axis C, the holding portion 22 has a curved shape with a smaller radius of curvature r than the writing portion 21.

[0048] Also, as shown in Fig. 5, in a longitudinal sectional view along the central axis C, the holding portion 22 has a constant vertical position over the entire front-rear length of the holding portion 22. That is, in this longitudinal sectional view, the holding portion 22 extends parallel to the central axis C.

[0049] As shown in Figs. 6 and 7, in a cross-sectional view perpendicular to the central axis C, the writing portion 21 extends curved in the circumferential direction. The writing portion 21 is composed of a combination of a plurality of curved portions with different radii of curvature r. Specifically, in this cross-sectional view, the writing portion 21 has different radii of curvature r at both end portions 21a and the central portion 21b in the circumferential direction (which may also be referred to as the left-right direction). The radius of curvature r of both end portions 21a in the circumferential direction of the writing portion 21 is larger than the radius of curvature r of the holding portion 22. Also, the radius of curvature r of the central portion 21b in the circumferential direction of the writing portion 21 is larger than the radius of curvature r of both end portions 21a in the circumferential direction of the writing portion 21. Note that a part of the plurality of curved portions constituting the writing portion 21 may have a radius of curvature smaller than the radius of curvature r of the holding portion 22.

[0050] In addition, the radius of curvature r of both end portions 21a in the circumferential direction of the writing portion 21 increases as it goes forward from the connecting portion (boundary portion) 23 with the holding portion 22. Also, the radius of curvature r of the central portion 21b in the circumferential direction of the writing portion 21 increases as it goes forward from the connecting portion 23.

[0051] The center Cr of the radius of curvature r of both end portions 21a in the circumferential direction of the writing portion 21 is located below the central axis C of the fountain pen 10. Also, the center (not shown) of the radius of curvature r of the central portion 21b in the circumferential direction of the writing portion 21 is located further below the center Cr of the radius of curvature r of both end portions 21a in the circumferential direction of the writing portion 21. Also, in the longitudinal sectional view shown in FIG. 5, the writing portion 21 extends downward as it goes forward from the connecting portion 23 with the holding portion 22.

[0052] As shown in FIGS. 2 to 4, the pen body 2 has a cut 2a, a heart hole 2b, a shoulder 2c, a first protrusion 2d, a recess 2e, and a notch 2f.

[0053] The cut 2a is disposed in the writing portion 21 and extends in the front-rear direction, forming a slit shape that penetrates the pen body 2 in the plate thickness direction. Specifically, the cut 2a penetrates the writing portion 21 in the vertical direction (that is, it opens to the upper and lower surfaces of the pen body 2) and also opens to the front at the front end of the writing portion 21. The cut 2a is disposed at the central portion of the writing portion 21 in the left-right direction.

[0054] The heart hole 2b is disposed in the writing portion 21 and forms a hole shape that penetrates the pen body 2 in the plate thickness direction. In the illustrated example, the heart hole 2b is circular. The heart hole 2b is disposed at the central portion of the writing portion 21 in the left-right direction. The heart hole 2b is connected to the rear end portion of the cut 2a and communicates with the cut 2a.

[0055] The shoulder portions 2c are disposed on the writing portion 21 and project outward in the left - right direction. A pair of shoulder portions 2c are provided on the pen body 2. One of the pair of shoulder portions 2c projects from the writing portion 21 toward the left side, and the other projects from the writing portion 21 toward the right side. That is, the pair of shoulder portions 2c project outward in both the left and right directions. In the present embodiment, the pair of shoulder portions 2c are disposed on the front side of the heart - shaped hole 2b.

[0056] The shoulder portion 2c is the portion that projects most in the left - right direction (left side or right side) in the writing portion 21. In the present embodiment, the shoulder portion 2c is also the portion that projects most in the left - right direction in the entire pen body 2. The shoulder portion 2c has a triangular plate shape that is convex in the left - right direction.

[0057] The portion of the writing portion 21 located on the front side of the shoulder portion 2c has a smaller dimension in the left - right direction as it goes forward from the shoulder portion 2c. The portion of the writing portion 21 located on the front side of the shoulder portion 2c has a tapered shape toward the front in the top - view shown in FIG. 4. Also, the portion of the writing portion 21 located on the rear side of the shoulder portion 2c has a smaller dimension in the left - right direction as it goes backward from the shoulder portion 2c.

[0058] The first protrusions 2d are disposed on the holding portion 22 and project outward in the left - right direction. A pair of first protrusions 2d are provided on the pen body 2. One of the pair of first protrusions 2d projects from the holding portion 22 toward the left side, and the other projects from the holding portion 22 toward the right side. That is, the pair of first protrusions 2d project outward in both the left and right directions. The pair of first protrusions 2d are disposed at the rear end portion of the holding portion 22 (i.e., the rear end portion of the pen body 2).

[0059] The first protrusion 2d is the portion that projects most in the left - right direction (left side or right side) in the holding portion 22. That is, the first protrusion 2d protrudes more in the left - right direction than the other portions of the holding portion 22 other than the first protrusion 2d. In the present embodiment, the first protrusion 2d has a rectangular plate shape that is convex in the left - right direction.

[0060] The recessed portion 2e is disposed in the holding portion 22 and is recessed inward in the left-right direction from the outer edges on the left and right sides of the pen body 2. A pair of recessed portions 2e are provided on the pen body 2. One of the pair of recessed portions 2e has a concave shape that recesses from the left edge of the holding portion 22 to the right, and the other has a concave shape that recesses from the right edge of the holding portion 22 to the left. That is, the pair of recessed portions 2e are recessed inward (toward the center in the circumferential direction) from both end edges (both end edges in the circumferential direction) of the holding portion 22 (pen body 2) in the left-right direction.

[0061] The recessed portion 2e is disposed between the shoulder portion 2c and the first protrusion 2d in the front-rear direction. Specifically, the recessed portion 2e is disposed in the middle portion located between both end portions in the front-rear direction of the holding portion 22. More specifically, the recessed portion 2e is disposed adjacent to and in front of the first protrusion 2d.

[0062] In the present embodiment, the recessed portion 2e has a substantially rectangular notch shape. The dimension of the recessed portion 2e in the left-right direction (which may also be referred to as the dimension in the circumferential direction) is smaller than the dimension of the recessed portion 2e in the front-rear direction. Also, in the holding portion 22, the portion located between the pair of recessed portions 2e in the left-right direction (circumferential direction) has a larger dimension in the left-right direction (circumferential direction) compared to each recessed portion 2e.

[0063] The notch portion 2f is disposed in the holding portion 22 and is recessed forward from the rear edge of the pen body 2. The notch portion 2f is disposed at the center of the holding portion 22 in the left-right direction. The notch portion 2f has a substantially trapezoidal notch shape.

[0064] The notch portion 2f is arranged so as to overlap the first protrusion 2d and not overlap the recessed portion 2e when viewed from the left-right direction (circumferential direction). In other words, the notch portion 2f has the same position as the first protrusion 2d in the front-rear direction and a different position from the recessed portion 2e in the front-rear direction. The notch portion 2f is used, for example, for positioning (centering) when forming the cut 2a during the manufacture of the pen body 2.

[0065] Further, the pen body 2 includes a pen tip 24 disposed at the front end of the writing portion 21, and a main body portion 25 that constitutes the portion of the pen body 2 other than the pen tip 24. The main body portion 25 includes the portion of the writing portion 21 other than the pen tip 24 and the holding portion 22.

[0066] The pen tip 24 is provided at the front end of the writing portion 21 by welding or the like. The pen tip 24 is provided to suppress wear of the pen body 2 and to adjust the line width during writing. A pair of pen tips 24 are provided on both outer sides in the left-right direction at the front end of the cutting 2a, and the pair of pen tips 24 as a whole has a substantially spherical shape. The pen tip 24 is made of, for example, an alloy containing iridium or the like.

[0067] The main body portion 25 is integrally formed by a single member. The main body portion 25 is made of metal, specifically, a plate-shaped metal material with high spring properties. The main body portion 25 has a Young's modulus of 230 GPa or less and a 0.2% proof stress (yield stress) of 800 MPa or more. When a metal having a stress-strain diagram with a yield point is used as the pen body, the above "0.2% proof stress" may be replaced with "upper yield point".

[0068] Specifically, in the present embodiment, the main body portion 25 is made of a Co-Ni-based alloy having a mass ratio as follows. <Mass ratio> Co: 30.9~37.2%, Ni: 31.4~33.4%, Cr: 19.5~20.5%, Mo: 9.5~10.5%, Mn: 0.1~0.5%, Ti: 0.3~0.7%, Fe: 1.1~2.1%, Nb: 0.8~1.2%, Rare earth metal: 0.01~0.02%, And unavoidable impurities.

[0069] As the main body 25 of the present embodiment, for example, a product name: SPRON510 (registered trademark) manufactured by Seiko Instruments Inc. can be used. In the present embodiment, the Young's modulus of the main body 25 is, for example, 210 GPa or more and 230 GPa or less. Also, the 0.2% proof stress of the main body 25 is, for example, 1700 MPa or more and 1900 MPa or less. Further, the Vickers hardness of the main body 25 is, for example, 450 Hv or more and 800 Hv or less.

[0070] As shown in FIGS. 1 and 2, the pen core 1 has a substantially cylindrical shape extending in the front-rear direction around the central axis C. The pen core 1 has an ink groove 11 extending in the front-rear direction, a plurality of comb grooves 12 communicating with the ink groove 11 and arranged side by side in the front-rear direction, a convex portion 13 protruding from the outer peripheral surface of the pen core 1, and a concave ink reservoir portion 14 arranged on the outer peripheral surface of the pen core 1.

[0071] The ink groove 11 extends in the front-rear direction inside the pen core 1. The ink groove 11 opens at the upper end portion of the outer peripheral surface of the pen core 1. The front end portion of the ink groove 11 is located directly below the cut 2a and the heart hole 2b of the pen body 2. The rear end portion of the ink groove 11 communicates with an ink storage portion (not shown), and the front end portion thereof communicates with the cut 2a.

[0072] The comb groove 12 is recessed radially inward from the outer peripheral surface of the pen core 1 and extends in the circumferential direction. The plurality of comb grooves 12 are arranged at intervals in the front-rear direction. The portion of the pen core 1 located between the comb grooves 12 adjacent to each other in the front-rear direction is a comb tooth 15. A plurality of comb teeth 15 are provided at intervals in the front-rear direction (by the groove width dimension of the comb groove 12). Each comb tooth 15 has a plate shape spreading in a direction perpendicular to the front-rear direction.

[0073] The convex portions 13 are arranged at portions (i.e., the outer peripheral surfaces of the comb teeth 15) located between the adjacent comb grooves 12 in the front-rear direction on the outer peripheral surface of the pen core 1. The convex portions 13 are arranged at the upper portion of the outer peripheral surface of the pen core 1. A plurality of convex portions 13 are provided side by side in the front-rear direction. The plurality of convex portions 13 are arranged at intervals from each other in the front-rear direction. A comb groove 12 is located between the adjacent convex portions 13 in the front-rear direction.

[0074] As shown in FIGS. 1 and 2, in a state where the pen body 2 is overlapped and arranged on the pen core 1, the convex portions 13 are arranged in the concave portions 2e of the pen body 2. Specifically, in the present embodiment, a plurality (four) of convex portions 13 are respectively arranged side by side in the front-rear direction in the pair of concave portions 2e. Each convex portion 13 can be locked to the concave portion 2e in the front-rear direction or the left-right direction.

[0075] Specifically, among the four convex portions 13 arranged in each concave portion 2e, the convex portion 13 located at the foremost side can be locked to the front wall facing the rear side, which is located at the front end of the concave portion 2e. Also, among the above four convex portions 13, the convex portion 13 located at the rearmost side can be locked to the rear wall facing the front side, which is located at the rear end of the concave portion 2e. Further, each of the above four convex portions 13 can be locked to the side wall facing the outer side in the left-right direction, which is located at the inner end portion (the central side end portion) in the left-right direction of the concave portion 2e.

[0076] The ink reservoirs 14 are arranged at portions (i.e., the outer peripheral surfaces of the comb teeth 15) located between the adjacent comb grooves 12 in the front-rear direction on the outer peripheral surface of the pen core 1. The ink reservoirs 14 are arranged at the upper portion of the outer peripheral surface of the pen core 1. A plurality of ink reservoirs 14 are provided side by side in the front-rear direction. The plurality of ink reservoirs 14 are arranged at intervals from each other in the front-rear direction. A comb groove 12 is located between the adjacent ink reservoirs 14 in the front-rear direction. The ink reservoirs 14 and the comb grooves 12 communicate with each other.

[0077] Each ink reservoir portion 14 is disposed adjacent to each convex portion 13 on the outer side in the left - right direction of each convex portion 13. At least a part of each ink reservoir portion 14 is located within the recess 2e. In the present embodiment, the ink reservoir portion 14 and the first protrusion 2d of the pen body 2 are arranged so as to overlap when viewed from the front - rear direction.

[0078] Although not particularly shown, the cap has a top - capped cylindrical shape centered on the central axis C and extends in the axial direction. The front - end portion of the peripheral wall of the cap is closed by the top wall, and the rear - end portion of the peripheral wall is open. The rear - end opening of the cap is detachably fitted to the neck cylinder 31. That is, the cap is detachably attached to the shaft cylinder 3. The cap attached to the shaft cylinder 3 covers the pen core 1 and the pen body 2 from the front side and from the radially outer side over the entire circumference in the circumferential direction.

[0079] Next, a method for manufacturing the pen body 2 of the fountain pen 10 of the present embodiment will be described with reference to FIGS. 9 and 10. The method for manufacturing the pen body 2 of the fountain pen 10 of the present embodiment includes a punching step of punching a plate - shaped metal material to form a blank B, and a pressing step of forming the curved plate - shaped pen body 2 by pressing the blank B between a female die 52 and a male die 51. For the punching step, a well - known process similar to the conventional one can be used, and the description thereof is omitted here.

[0080] <Pressing Step> The pressing step of forming the pen body 2 and the die 50 used for pressing the pen body 2 will be described. FIG. 9 is a side - sectional view showing a part of the die 50, and FIG. 10 is a plan view showing the female die 52 of the die 50.

[0081] The vertical direction of the mold 50 described below is parallel to (the same as) the vertical direction (Z-axis direction) used in the description of the fountain pen 10 above, but the upper and lower directions are opposite to each other. Therefore, in order to distinguish the vertical direction of the mold 50 from the vertical direction of the fountain pen 10, in the following description, the vertical direction of the mold 50 is referred to as the "mold vertical direction". In FIGS. 9 and 10, among the mold vertical directions, the upper side of the mold corresponds to the -Z side, and the lower side of the mold corresponds to the +Z side.

[0082] The mold 50 has a female mold 52 and a male mold 51 that faces the female mold 52 from the upper side of the mold. The male mold 51 is reciprocally movable in the mold vertical direction with respect to the female mold 52. Note that the male mold 51 may be referred to as a forming punch or the like, and the female mold 52 may be referred to as a forming die or the like.

[0083] The female mold 52 has a forming recess 52a, a positioning guide 53, a discharge pin 54, and a biasing means 55.

[0084] The forming recess 52a forms a groove-like shape that depresses from the upper surface of the female mold 52 facing the upper side of the mold toward the lower side of the mold, and extends in the front-rear direction. The inner surface of the forming recess 52a has a concave curved surface shape. Specifically, a cross-section perpendicular to the front-rear direction forms a concave curve shape that depresses toward the lower side of the mold.

[0085] The positioning guide 53 is detachably fixed to the upper surface of the female mold 52 facing the upper side of the mold using bolts 56 or the like. The positioning guide 53 is, for example, plate-shaped or the like. A pair of positioning guides 53 are provided on the female mold 52. The pair of positioning guides 53 are arranged adjacent to the forming recess 52a on both sides in the left-right direction of the forming recess 52a. That is, the pair of positioning guides 53 are arranged at intervals in the left-right direction, and the forming recess 52a is arranged between these positioning guides 53.

[0086] The pair of positioning guides 53 has a plurality (four) of positioning recesses 53a into which a pair of shoulders 2c and a pair of first protrusions 2d of the blank B that becomes the pen body 2 can be engaged. By fitting (engaging) the pair of shoulders 2c and the pair of first protrusions 2d of the blank B into the four positioning recesses 53a, the blank B before press working is positioned with respect to the female mold 52. Thus, in the press process of this embodiment, the pair of shoulders 2c and the pair of first protrusions 2d formed on the blank B are used as positioning means for the female mold 52.

[0087] The ejection pin 54 is provided inside the female mold 52 so as to be movable in the mold vertical direction. The upper mold end of the ejection pin 54 can project in and out from the inner surface of the forming recess 52a. As shown in FIG. 10, the upper mold end of the ejection pin 54 is disposed to face a portion of the holding portion 22 of the pen body 2 after press forming that is located between a pair of recesses 2e in the left - right direction. Also, the upper mold end of the ejection pin 54 is preferably disposed to face a portion close to the connecting portion 23 among the holding portions 22. Note that, when viewed in the mold vertical direction, a part of the upper mold end of the ejection pin 54 may overlap with the recess 2e.

[0088] As shown in FIG. 9, the biasing means 55 is disposed inside the female mold 52 and biases the ejection pin 54 upward in the mold. The biasing means 55 is, for example, a compression coil spring or the like.

[0089] The male mold 51 has a forming convex portion 51a. The forming convex portion 51a is in the shape of a rib protruding downward in the mold from the lower surface facing the lower side of the male mold 51 and extends in the front - rear direction. The outer surface of the forming convex portion 51a is in a convex curved surface shape. Specifically, a cross - section perpendicular to the front - rear direction is in a convex curve shape protruding downward in the mold.

[0090] During the pressing process using the mold 50 configured as described above, first, with the female mold 52 and the male mold 51 separated from each other in the vertical direction of the mold, the blank B is set on the upper surface of the female mold 52. Specifically, the blank B is positioned with respect to the female mold 52 by locking a pair of shoulders 2c and a pair of first protrusions 2d of the flat blank B to the four positioning recesses 53a of the female mold 52.

[0091] Next, when the male mold 51 is moved downward with respect to the female mold 52, the forming convex portion 51a fits into the forming concave portion 52a while forming the blank B into a curved shape. As a result, the blank B is press-formed into the shape of the pen body 2 described above. Also, in this process, the discharge pin 54 is pushed down by the forming convex portion 51a via the blank B (pen body 2) and immerses from the inner surface of the forming concave portion 52a to the lower side of the mold.

[0092] Next, when the male mold 51 is moved upward with respect to the female mold 52, the forming convex portion 51a detaches from the inside of the forming concave portion 52a to the upper side of the mold. Along with this, the pushing force of the discharge pin 54 by the forming convex portion 51a is released, and the discharge pin 54 rises by the biasing force of the biasing means 55 and protrudes from the inner surface of the forming concave portion 52a to the upper side of the mold. As a result, the discharge pin 54 pushes up the holding portion 22 of the pen body 2 to the upper side of the mold, the pen body 2 detaches from the forming concave portion 52a, and is discharged from the female mold 52.

[0093] According to the fountain pen 10 of the present embodiment and the manufacturing method of the pen body 2 of the fountain pen 10 described above, the following operational effects can be obtained. During the manufacture of the fountain pen 10, the blank B punched from a plate-shaped metal material is press-processed between the molds 50 (male mold 51 and female mold 52), whereby the pen body 2 formed into a curved shape is obtained. The holding portion 22 of the pen body 2 is a portion sandwiched between the inner peripheral surface of the shaft cylinder 3 and the outer peripheral surface of the pen core 1, and has a curved shape (arc shape) with a smaller radius of curvature r in a cross-sectional view perpendicular to the central axis C compared to the writing portion 21 exposed outside the shaft cylinder 3.

[0094] In a conventional fountain pen, when a highly springy metal material is used for the pen body, among the parts of the pen body, especially the holding part with a small radius of curvature is likely to fit into the forming recess of the female mold due to springback after press working, making it difficult to release from the mold.

[0095] On the other hand, in the fountain pen 10 of the present embodiment, a recess 2e is formed in the holding part 22 of the pen body 2, and the recess 2e is recessed inward from the outer edge in the left - right direction of the pen body 2. Such a recess 2e suppresses the situation where the vicinity of the outer edge in the left - right direction of the pen body 2 is caught on the inner surface of the forming recess 52a of the female mold 52 (hereinafter, may be simply referred to as "the inner surface of the female mold 52") when the blank B is press - worked.

[0096] More specifically, even if the pen body 2 springs back greatly after press working by using a highly springy metal material, the contact resistance and catching between the holding part 22 and the inner surface of the female mold 52 are suppressed by the recess 2e provided at the outer end in the left - right direction of the holding part 22. Therefore, the holding part 22 is prevented from fitting into the female mold 52. For this reason, the pen body 2 can be press - worked efficiently. Also, the quality of the manufactured pen body 2 is maintained well.

[0097] Moreover, since the recess 2e is formed in the holding part 22 inserted into the front opening 31a of the shaft cylinder 3, it is not exposed to the outside of the fountain pen 10. Therefore, while the excellent effects described above are obtained by the recess 2e, the influence on the appearance design of the fountain pen 10 is suppressed.

[0098] From the above, according to the present embodiment, even when a highly springy metal material is used for the pen body 2, it is possible to prevent the problem that the pen body 2 after press working fits into the mold 50. Thereby, a high - quality fountain pen 10 can be manufactured efficiently, and productivity can be improved.

[0099] The reason for forming the pen body 2 into a curved plate shape is as follows. That is, for example, it is also possible to use it as a fountain pen by assembling it with a pen core while keeping the pen body almost uncurved and in a shape close to a flat blank. However, in this case, when a writing pressure load is applied to the pen body during writing, the pen point and cut of the pen body do not spread, and it does not have the characteristic undulating line width of a fountain pen.

[0100] On the other hand, as in the present embodiment, when the pen body 2 is in a curved plate shape, during writing, the pen point 24 and the cut 2a of the pen body 2 spread appropriately, and it is possible to obtain a characteristic undulating line width of a fountain pen. That is, the fountain pen 10 of the present embodiment realizes a characteristic and undulating line width while achieving the above-described excellent effects.

[0101] Also, in the present embodiment, the pen body 2 has a pair of shoulders 2c disposed in the writing portion 21 and protruding outward in the left-right direction, and a pair of first protrusions 2d disposed in the holding portion 22 and protruding outward in the left-right direction. The concave portion 2e is disposed between the shoulder 2c and the first protrusion 2d in the front-rear direction.

[0102] In this case, the pen body 2 is provided with four protruding portions (a pair of shoulders 2c and a pair of first protrusions 2d) arranged at intervals in the front-rear direction and the left-right direction. When setting the blank B to be the pen body 2 in the mold 50 for pressing, the above four protruding portions 2c, 2d can be used as positioning means for the mold 50. Thereby, the accuracy of the pressing process is stably enhanced.

[0103] And in the above configuration, the concave portion 2e is disposed between the shoulder 2c and the first protrusion 2d in the front-rear direction. Thereby, the above-described effect of preventing fitting into the female mold 52 by the concave portion 2e is achieved more stably.

[0104] Also, in the present embodiment, the pen body 2 includes a pen tip 24 disposed at the front end of the writing part 21, and a main body part 25 that constitutes the part of the pen body 2 other than the pen tip 24. The main body part 25 is made of metal, has a Young's modulus of 230 GPa or less, and a 0.2% proof stress of 800 MPa or more.

[0105] Generally, the springback amount after press working of a metal material becomes larger as the Young's modulus becomes lower, and also becomes larger as the 0.2% proof stress (yield stress) becomes higher. When the Young's modulus of the metal material constituting the main body part 25 of the pen body 2 is 230 GPa or less and the 0.2% proof stress is 800 MPa or more as in the above configuration, the springback amount after press working tends to be large. Even when a metal material with a large springback is used for the pen body 2, according to the present embodiment, by providing the concave portion 2e, the fitting into the female mold 52 can be stably suppressed. In particular, in the present embodiment, even when a metal material with a 0.2% proof stress of 850 MPa or more is used for the main body part 25 of the pen body 2, the fitting into the female mold 52 due to springback can be stably suppressed.

[0106] Also, in the present embodiment, the pen core 1 has a convex portion 13 that protrudes from the outer peripheral surface of the pen core 1 and is disposed in the concave portion 2e, and the convex portion 13 can be locked to the concave portion 2e in the front-rear direction or the left-right direction.

[0107] In this case, when the convex portion 13 protruding from the outer peripheral surface of the pen core 1 is locked to the concave portion 2e of the pen body 2, the relative movement in the front-rear direction or the left-right direction between the pen core 1 and the pen body 2 is restricted. As a result, the pen body 2 is prevented from coming out (forward movement), being pushed in (rearward movement), and rotating around the central axis C with respect to the pen core 1. According to the fountain pen 10 of the present embodiment, since the mounting posture of the pen body 2 with respect to the pen core 1 is stable, a good writing feeling can be stably maintained.

[0108] Also, in the present embodiment, the following operational effects are further obtained by the concave portion 2e. Generally, in the pen body, there is a portion where it is preferable to reduce the radius of curvature in a cross-sectional view perpendicular to the central axis. For example, after assembling the pen body and the pen core, the pair of shoulders of the pen body may be provided with a function of preventing lateral movement of the pen body with respect to the pen core. From the perspective of preventing such lateral movement, in the cross-sectional view shown in FIG. 6, rather than increasing the radius of curvature r of the writing portion 21 over the entire circumferential direction, it is preferable to partially reduce the radius of curvature r.

[0109] Specifically, in the cross-sectional view shown in FIG. 6, by reducing the radius of curvature of the portion located between both end portions 21a and the central portion 21b in the circumferential direction (the connection portion between each end portion 21a and the central portion 21b; hereinafter simply referred to as the connection portion), the above-described function of preventing lateral movement can be more easily obtained. However, if the radius of curvature of this connection portion becomes too small, when pressing the blank B of a metal material with a large springback amount into the pen body 2, there is a possibility that the vicinity of the pair of shoulders 2c may fit into the female mold 52. For this reason, the radius of curvature of the above-described connection portion cannot be reduced to a predetermined value or less, and thus the above-described effect of preventing lateral movement cannot be sufficiently obtained.

[0110] In this regard, in the present embodiment, a concave portion 2e is provided in the pen body 2, and in a state where the pen body 2 and the pen core 1 are assembled, the concave portion 2e and the convex portion 13 are locked. Thereby, an effect of preventing lateral movement of the pen body 2 with respect to the pen core 1 can be obtained. Therefore, there is no need to reduce the radius of curvature of the above-described connection portion to a predetermined value or less. For this reason, according to the present embodiment, while suppressing the fitting of the vicinity of the shoulder 2c of the pen body 2 into the female mold 52, an effect of preventing lateral movement of the pen body 2 can be sufficiently obtained.

[0111] In addition, in the present embodiment, the pen core 1 includes an ink groove 11 extending in the front-rear direction, a plurality of comb grooves 12 communicating with the ink groove 11 and arranged side by side in the front-rear direction, and a concave ink reservoir portion 14 disposed on a portion (outer peripheral surface of the comb teeth 15) of the outer peripheral surface of the pen core 1 located between adjacent comb grooves 12 in the front-rear direction. The ink reservoir portion 14 is disposed adjacent to the convex portion 13 on the outer side in the left-right direction of the convex portion 13.

[0112] For example, when the internal pressure of the ink reservoir provided inside the fountain pen 10 is increased above the external pressure due to a decrease in air pressure, a rise in temperature, or the like, the ink that has overflowed from the ink reservoir is temporarily held in the plurality of comb grooves 12 via the ink groove 11. According to the above configuration of the present embodiment, since the pen core 1 further has the ink reservoir portion 14, the overflowed ink can be held by the plurality of comb grooves 12 and the ink reservoir portion 14.

[0113] Moreover, the manufacturing method of the pen body 2 of the fountain pen 10 in the present embodiment includes a punching step of punching a plate-shaped metal material to obtain a blank B, and a pressing step of forming the curved plate-shaped pen body 2 by pressing the blank B between a female mold 52 and a male mold 51. In the pressing step, a pair of shoulders 2c and a pair of first protrusions 2d formed on the blank B are used as positioning means for the female mold 52.

[0114] That is, in the manufacturing method of the pen body 2 of the fountain pen 10 in the present embodiment, when the blank B is set in the female mold (forming die) 52 and pressed, four protruding portions (a pair of shoulders 2c and a pair of first protrusions 2d) are used as positioning means for the female mold 52. Thereby, the accuracy of the pressing process can be stably enhanced.

[0115] And in the present embodiment, as described above, the concave portion 2e is disposed between the shoulder portion 2c and the first protrusion 2d in the front-rear direction. By providing such a concave portion 2e, even when a metal material with high springiness (a large springback amount) as in the present embodiment is used for the pen body 2, it is possible to prevent the pen body 2 from fitting into the female mold 52 after the pressing process.

[0116] In the present embodiment, among the holding portions 22, the portion located between the pair of concave portions 2e in the left - right direction (circumferential direction) has a larger dimension in the left - right direction (circumferential direction) than each of the concave portions 2e.

[0117] In this case, while ensuring the rigidity of the holding portion 22, the above - described effects of the concave portion 2e are stably achieved. Further, by pressing the portion of the holding portion 22 located between the pair of concave portions 2e where the rigidity is ensured with the discharge pin 54, the pen body 2 after press - working can be stably discharged from the forming concave portion 52a.

[0118] In the present embodiment, since the discharge pin 54 presses the holding portion 22, even when indentations due to pressing are formed in the holding portion 22, these indentations are disposed within the front opening 31a of the shaft cylinder 3. Therefore, the influence on the external design of the fountain pen 10 can be suppressed.

[0119] The present invention is not limited to the above - described embodiments. For example, as described below, modifications such as changes in the configuration are possible without departing from the gist of the present invention. In the illustration of the modified example, the same reference numerals are given to the same configurations as those in the above - described embodiments, and the following mainly describes the different points.

[0120] FIG. 11 is a top view showing a blank B that becomes the pen body 2 of the fountain pen 10 according to a modified example of the above - described embodiment. That is, in the modified example, the pen body 2 formed by pressing and shaping this blank B is provided in the fountain pen 10. Note that the blank B shown in FIG. 11 represents the state before providing the pen tip 24 and the cut 2a.

[0121] In this modification, the blank B, that is, the pen body 2, is disposed between a pair of shoulders 2c and a pair of first protrusions 2d in the front-rear direction, and has a pair of second protrusions 2g protruding toward both outer sides in the left-right direction. The pair of second protrusions 2g are disposed in the holding portion 22, and specifically, are disposed at the front end portion of the holding portion 22 (the portion of the holding portion 22 adjacent to the connecting portion 23). One of the pair of second protrusions 2g protrudes from the holding portion 22 toward the left side, and the other protrudes from the holding portion 22 toward the right side.

[0122] The second protrusion 2g protrudes more in the left-right direction than the portions of the holding portion 22 other than the second protrusion 2g and the first protrusion 2d. In the illustrated example, the amount of protrusion of the second protrusion 2g in the left-right direction is the same as the amount of protrusion of the first protrusion 2d in the left-right direction. Further, the second protrusion 2g has a quadrangular plate shape that is convex in the left-right direction.

[0123] Although not particularly shown, in the case of this modification, among the dies 50 used for press working the blank B (pen body 2), the pair of positioning guides 53 of the female die 52 have a plurality (six) of positioning recesses 53a into which the pair of shoulders 2c, the pair of first protrusions 2d, and the pair of second protrusions 2g of the blank B can be engaged. By fitting (engaging) the pair of shoulders 2c, the pair of first protrusions 2d, and the pair of second protrusions 2g of the blank B into the six positioning recesses 53a, the blank B before press working is positioned with respect to the female die 52. That is, in this modification, in the press process, the pair of shoulders 2c, the pair of first protrusions 2d, and the pair of second protrusions 2g formed on the blank B are used as positioning means for the female die 52.

[0124] According to the above modification, the blank B (pen body 2) is provided with six protruding portions (a pair of shoulders 2c, a pair of first protrusions 2d, and a pair of second protrusions 2g) that are spaced apart from each other in the front-rear direction and the left-right direction. When setting the blank B in the die 50 and performing press working, the six protruding portions 2c, 2d, 2g can be used as positioning means for the die 50. Thereby, the accuracy of press working is more stably improved.

[0125] Further, in this modification, the concave portion 2e is disposed between the first protrusion 2d and the second protrusion 2g in the front-rear direction. Thereby, the above-described effect of preventing the fitting into the female mold 52 by the concave portion 2e is stably achieved.

[0126] Also, in the above-described embodiment, an example in which the trade name: SPRON510 (registered trademark) manufactured by Seiko Instruments Inc. is used as the metal material constituting the main body portion 25 of the pen body 2 has been given, but the present invention is not limited thereto. As the metal material constituting the main body portion 25, for example, a titanium alloy, high-tensile steel, or the like may be used.

[0127] Specifically, examples of the titanium alloy include 64 titanium alloy (Ti-6Al-4V), β-Ti 15-3-3-3 (beta titanium Ti-15V-3Cr-3Sn-3Al), and the like. More specifically, the 64 titanium alloy (Ti-6Al-4V) used for the main body portion 25 has a Young's modulus of, for example, 100 GPa or more and 120 GPa or less. Also, the 0.2% proof stress (yield strength) is, for example, 800 MPa or more and 1200 MPa or less. Also, the β-Ti 15-3-3-3 (beta titanium Ti-15V-3Cr-3Sn-3Al) used for the main body portion 25 has a Young's modulus of, for example, 80 GPa or more and 100 GPa or less. Also, the 0.2% proof stress (yield strength) is, for example, 800 MPa or more and 1100 MPa or less.

[0128] Also, the shape of the pen body 2 is not limited to the shape (substantially pentagonal plate shape) described in the above-described embodiment and modification. Although not particularly shown, for example, a pen body having no pair of shoulder portions 2c and having a substantially triangular plate shape as a whole may be used. In this case, at the time of press working for forming the blank into the pen body, by using the pen point 24 as a part of the positioning means for the mold instead of the pair of shoulder portions 2c, the processing accuracy of the forming may be improved.

[0129] Within the scope not departing from the gist of the present invention, the respective configurations described in the foregoing embodiments, modifications, and the like may be combined, and addition, omission, substitution, and other changes to the configuration are possible. Further, the present invention is not limited by the foregoing embodiments and the like, but is limited only by the scope of the claims.

Industrial Applicability

[0130] According to the fountain pen of the present invention and the method for manufacturing the pen body of the fountain pen, even when a metal material with high springiness is used as the pen body, it is possible to prevent the problem that the pen body after pressing gets stuck in the mold. As a result, a high-quality fountain pen can be efficiently manufactured, and productivity can be improved. Therefore, it has industrial applicability.

Explanation of Reference Numerals

[0131] 1... pen core, 2... pen body, 2c... shoulder portion, 2d... first protrusion, 2e... recess, 2g... second protrusion, 3... shaft cylinder, 10... fountain pen, 11... ink groove, 12... comb groove, 13... convex portion, 14... ink reservoir, 15... comb teeth, 21... writing portion, 22... holding portion, 24... pen tip, 25... main body portion, 31a... front opening, 51... male mold, 52... female mold, B... blank, C... central axis

Claims

1. A pen refill extending in the front-rear direction along a central axis, A curved plate-shaped pen body disposed on the upper portion of the outer peripheral surface of the pen refill, A shaft cylinder having a front opening into which each rear portion of the pen refill and the pen body is inserted, and comprising: The pen body is, A writing portion disposed in front of the shaft cylinder, A holding portion disposed behind the writing portion, inserted into the front opening, and held between the inner peripheral surface of the shaft cylinder and the outer peripheral surface of the pen refill, A concave portion disposed in the holding portion and recessed inward in the left-right direction from the outer edges on the left and right sides of the pen body, A fountain pen.

2. The pen body is, A pair of shoulders disposed in the writing portion and protruding outward in both the left and right directions, A pair of first protrusions disposed in the holding portion and protruding outward in both the left and right directions, The concave portion is disposed between the shoulders and the first protrusions in the front-rear direction, The fountain pen according to claim 1.

3. The pen body is disposed between the pair of shoulders and the pair of first protrusions in the front-rear direction and has a pair of second protrusions protruding outward in both the left and right directions, The fountain pen according to claim 2.

4. The pen body is, A pen tip disposed at the front end of the writing portion, A main body portion constituting the portion of the pen body other than the pen tip, The main body portion is made of metal, has a Young's modulus of 230 GPa or less, and a 0.2% proof stress of 800 MPa or more, The fountain pen according to any one of claims 1 to 3.

5. The pen refill has a convex portion protruding from the outer peripheral surface of the pen refill and disposed in the concave portion, The convex portion is engageable with the concave portion in the front-rear direction or the left-right direction, The fountain pen according to any one of claims 1 to 3.

6. The pen refill is, An ink groove extending in the front-rear direction, A plurality of comb grooves communicating with the ink groove and arranged side by side in the front-rear direction, A concave ink reservoir portion disposed at a portion of the outer peripheral surface of the pen refill located between the adjacent comb grooves in the front-rear direction, The ink reservoir portion is disposed outside the convex portion in the left-right direction and adjacent to the convex portion, The fountain pen according to claim 5.

7. A method for manufacturing the pen body of the fountain pen according to claim 2, comprising: A punching step of punching a plate-shaped metal material to form a blank, A pressing step of forming the curved plate-shaped pen body by pressing the blank between a female die and a male die. In the pressing step, the pair of shoulders and the pair of first protrusions formed on the blank are used as positioning means for the female mold. A method for manufacturing a pen body of a fountain pen.

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