Writing utensil

Abstract

To provide a writing utensil equipped with an additional member which can be easily disassembled as intended while preventing unintended disassembly.SOLUTION: A writing utensil 1 comprises a rear barrel 10, an inner cylinder 20 inserted into the inside from a first opening end of the rear barrel 10, and a clip member 40 having a first projection piece 31 held by an inner surface of the rear barrel 10 and an outer surface of the inner cylinder 20. The inner surface of the rear barrel 10 or the outer surface of the inner cylinder 20 may have the first projection piece 31 and a first recess 13 for fitting the first projection piece 31 to the first recess 13 by disposing the first recess 13 capable of receiving the first projection piece 31.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a writing instrument.

Background Art

[0002] A writing instrument mainly comprises a component formed of a resin material and a component formed of a metal material adopted from the viewpoints of durability or design. Examples of the component of the resin material include a shaft cylinder and an ink storage tube of a refill. Examples of the component of the metal material include a clip member for gripping an article and a ball pen tip of a refill.

[0003] For example, Patent Document 1 discloses a writing instrument in which a clip member made of a resin material can be easily attached and detached. Specifically, a projecting piece extending rearward is formed on a side surface of a shaft cylinder, and a crown provided with a projecting portion is fitted to a rear end portion of the shaft cylinder with an attachment portion of the clip member inserted into the projecting piece. By the rear end surface of the projecting piece and the front end surface of the projecting portion coming into contact with each other, the attachment portion of the clip member is surrounded, and the clip member is attached to the shaft cylinder.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, from the perspective of environmental protection, it is preferable to recycle even the writing instruments that have become unnecessary. In this case, the writing instruments are roughly classified into parts made of resin materials and parts made of metal materials. The resin materials of the parts differ depending on the required resin type according to the part where the part is used. Specifically, since durability is required for the shaft tube, it is formed from, for example, polycarbonate. The gripping part (grip) provided on the shaft tube is formed from, for example, a thermoplastic elastomer because flexibility is required rather than durability since the user directly grips it during writing. When recycling parts of different resin types, it is preferable to separate these parts according to the resin type. In short, it is desirable that the writing instrument is not easily disassembled during normal use but can be easily disassembled during recycling.

[0006] The writing instrument described in Patent Document 1 has a structure in which the clip member is easily detachable. Therefore, for example, when the crown is removed during refilling replacement, the clip member may also accidentally come off. Further, in the case of a writing instrument in which a clip member made of a metal material is attached to a shaft tube made of a resin material or the like, the clip member is often firmly attached to the shaft tube and is not easily disassembled.

[0007] Patent Document 1 disclosed the attachment structure of an additional member, which is an additional member for the writing instrument, the clip member. However, also in the writing instrument having other additional members, it is preferable that the additional member is easily disassembled as intended while preventing unintentional disassembly.

[0008] An object of the present invention is to provide a writing instrument including an additional member that is easily disassembled as intended while preventing unintentional disassembly.

Means for Solving the Problems

[0009] According to one aspect of the present invention, there is provided a writing instrument including a first cylindrical member, an insertion member inserted into the first cylindrical member from a first opening end portion thereof, and an additional member having a sandwiching portion sandwiched between an inner surface of the first cylindrical member and an outer surface of the insertion member.

[0010] A receiving recess capable of receiving the clamping portion may be provided on the inner surface of the first cylindrical member or the outer surface of the insertion member. The clamping portion and the receiving recess may be formed such that the clamping portion fits into the receiving recess. The additional member may be a clip member or a part of a clip member. The writing instrument may further include a second cylindrical member connected to the second opening end of the first cylindrical member, and the first cylindrical member may be a rear shaft and the second cylindrical member may be a front shaft. The additional member may be formed of a material different from that of the first cylindrical member. A part or all of the additional member may be formed of a metal material, and the first cylindrical member may be formed of a resin material.

Advantages of the Invention

[0011] According to an aspect of the present invention, there is a common effect of providing a writing instrument provided with an additional member that is easy to disassemble as intended while preventing unintentional disassembly.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

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Figure 8

Figure 9

Figure 10

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Figure 15

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Figure 17

Figure 18

Figure 19

MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Throughout the drawings, common reference numerals are given to corresponding components.

[0014] FIG. 1 is a perspective view of a writing instrument 1 according to the first embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of the writing instrument 1 of FIG. 1. The writing instrument 1 is a so-called knock-type writing instrument.

[0015] The writing instrument 1 includes a shaft cylinder 2 having a front shaft 3, a rear shaft 10 disposed behind the front shaft 3, and an inner cylinder 20 disposed through the rear shaft 10, a refill 4 which is a writing body disposed in the shaft cylinder 2 and has a writing portion 4a at one end, and a spring 5 which is an elastic member for biasing the refill 4 rearward. A clip member 40 is attached to the side surface of the shaft cylinder 2 via a leaf spring 30. In this specification, in the axial direction of the writing instrument 1, the side of the writing portion 4a is defined as the "front" side, and the side opposite to the writing portion 4a is defined as the "rear" side.

[0016] A known knock mechanism is disposed inside the rear end portion of the shaft cylinder 2. The knock mechanism has a rotor 6 disposed movably in the front-rear direction, and an operation member 7 which protrudes rearward from the rear end opening of the shaft cylinder 2 and is disposed behind the rotor 6 and is movable in the front-rear direction. The rotor 6 and the operation member 7 are biased rearward together with the refill 4 by the spring 5.

[0017] The knock operation is performed by pressing the operation member 7 forward against the biasing force of the spring 5. As the operation member 7 moves due to the knock operation, the rotor 6 and the refill 4 are pressed and move forward inside the shaft cylinder 2. Then, when the force applied to the operation member 7 is released, the rotor 6 rotates around the central axis, and the rear end surface of the inner cam 6a formed on the outer peripheral surface of the rotor 6 and the front end surface of the outer cam 8 formed on the inner peripheral surface of the inner cylinder 20 are engaged. Thereby, the writing instrument 1 maintains a writing state in which the writing portion 4a protrudes from the tip of the shaft cylinder 2. When the knock operation is performed in the writing state of the writing instrument 1, the rotor 6 and the refill 4 are pressed as the operation member 7 moves and move forward inside the shaft cylinder 2, and the engagement between the rear end surface of the inner cam 6a of the rotor 6 and the front end surface of the outer cam 8 of the inner cylinder 20 is released. Then, when the force applied to the operation member 7 is released, the rotor 6 rotates around the central axis, and the refill 4 moves rearward by the biasing force of the spring 5. Thereby, the writing instrument 1 becomes a non-writing state (FIGS. 1 and 2) in which the writing portion 4a is immersed in the shaft cylinder 2.

[0018] The refill 4 is a refill for a ballpoint pen, but it may be other types of writing utensils such as a marking pen, a touch pen, an eraser, etc. other than a ballpoint pen. Also, part or all of the operating member 7 may be an erasing part for erasing the handwriting by the writing instrument 1. The refill 4 may contain a thermochromic ink containing a thermochromic coloring material. In this case, the writing instrument 1 is a thermochromic writing instrument, and the handwriting of the writing instrument 1 can be thermochromically changed by the frictional heat generated when rubbed by a friction body as an erasing member.

[0019] Here, the thermochromic ink refers to an ink that maintains a predetermined color (first color) at room temperature (for example, 25 °C), changes to another color (second color) when heated to a predetermined temperature (for example, 60 °C), and then returns to the original color (first color) again when cooled to a predetermined temperature (for example, -5 °C). In a writing instrument using thermochromic ink, making the second color colorless and heating the drawn line written in the first color (for example, red) to make it colorless is herein referred to as "erasing". Therefore, the friction body rubs against the writing surface on which the drawn line is written to generate frictional heat, thereby changing the drawn line to colorless, that is, erasing it. Of course, the second color may be a colored one other than colorless.

[0020] FIG. 3 is a perspective view of the inner cylinder 20 of the writing instrument 1 in FIG. 1, and FIG. 4 is a longitudinal sectional view of the inner cylinder 20 of the writing instrument 1 in FIG. 1.

[0021] The inner cylinder 20 is a cylindrical member. On the outer surface of the front end portion of the inner cylinder 20, a male screw portion 21 that engages with a female screw portion 3a formed on the inner surface of the rear end portion of the front shaft 3 is formed. On the inner surface of the rear end portion of the inner cylinder 20, the above-described outer cam 8 composed of a plurality of protrusions extending in the front-rear direction is formed. On the outer surface of the rear end portion of the inner cylinder 20, a flange portion 22 is formed. In a part of the flange portion 22, a receiving portion 23 configured to receive the clip member 40 is formed. The receiving portion 23 is formed in a substantially U shape that includes a surface formed with a radius of curvature larger than that of the side surface of the flange portion 22 and opens forward. The receiving portion 23 has a front end surface 23a at the same position as the front end surface of the flange portion 22 in the axial direction of the inner cylinder 20, and further has two protrusions 23b that extend forward from the front end surface 23a and constitute a U shape.

[0022] On the side surface of the inner cylinder 20 between the two protrusions 23b of the receiving portion 23, a second clamping surface 24 that extends forward from the front end surface 23a of the receiving portion 23 beyond the two protrusions 23b and corresponds to a first clamping surface 14 described later is formed. The second clamping surface 24 is formed in a rectangular shape as if shaving off the side surface of the cylindrical inner cylinder 20. On the central side surface of the inner cylinder 20 in the axial direction, two U-shaped holes 25 that are substantially U-shaped through holes opening forward are formed. The two U-shaped holes 25 are arranged to face each other with the central axis of the inner cylinder 20 interposed therebetween. By the U-shaped holes 25, a cantilever beam-shaped elastic deformation portion 26 extending rearward is defined. On the outer surface of the elastic deformation portion 26, a circular protrusion 27 is formed. Behind the male screw portion 21, an annular protrusion 28 is formed over the entire circumference.

[0023] FIG. 5 is an exploded perspective view of the rear shaft 10 and the clip member 40 of the writing instrument 1 in FIG. 1, and FIG. 6 is an exploded longitudinal sectional view of the rear shaft 10 and the clip member 40 of the writing instrument 1 in FIG. 1. The clip member 40 is attached to the rear shaft 10 by a leaf spring 30. In short, the leaf spring 30 is a part of the clip member 40, and it can be said that the clip member 40 has the leaf spring 30. With reference to FIGS. 5 and 6, the configurations of the rear shaft 10, the leaf spring 30, and the clip member 40 will be described.

[0024] The rear shaft 10 is a cylindrical member. A rectangular notch 11 is formed at the rear end of the rear shaft 10. On the side surface of the rear shaft 10 in front of the notch 11, a rectangular protrusion 12 which is a rectangular protrusion with a flat top surface is formed. The rectangular protrusion 12 has a rear end surface 12a orthogonal to the central axis of the rear shaft 10, and two substantially inclined side surfaces 12b and a front end surface 12c. On the inner surface of the rectangular protrusion 12, a first recess 13 which is a receiving recess extending in the axial direction is formed. The first recess 13 is formed in a substantially rectangular shape. A first clamping surface 14 is formed on the bottom surface of the first recess 13. On the inner surface of the front end of the rear shaft 10, four locking protrusions 15 are formed at equal intervals along the circumferential direction.

[0025] The leaf spring 30 is an elastic plate-like member. The leaf spring 30 is formed of a metal material, for example, a stainless steel material, but may be formed of a resin material. The leaf spring 30 is formed by bending an elongated substantially rectangular plate-like member so as to have a substantially U-shaped opening forward. The leaf spring 30 has a first protruding piece 31, a second protruding piece 32, and a connecting portion 33 connecting the first protruding piece 31 and the second protruding piece 32.

[0026] The connecting portion 33 is a portion curved to have a substantially the same radius of curvature. The connecting portion 33 is formed in an arc shape with a central angle of 180 degrees or more. The first protruding piece 31 and the second protruding piece 32 extend in the same direction and are substantially parallel. The first protruding piece 31 is shorter than the second protruding piece 32. The portion of the connecting portion 33 connected to the first protruding piece 31 has an inflection point in relation to the convex portion of the connecting portion 33 protruding radially outward. In other words, the connecting portion 33 formed in an arc shape with a central angle of 180 degrees or more has a concave inflection portion 34 protruding radially inward on the first protruding piece 31 side. The second protruding piece 32 is connected so as to extend in a tangential direction with respect to the connecting portion 33. A convex support portion 35 is provided at a position 180 degrees from the connection point between the second protruding piece 32 and the connecting portion 33, that is, on the side opposite to the connection point.

[0027] The clip member 40 is a rod-shaped member. On the inner surface of the front end portion of the clip member 40 in the assembled state, that is, on the side facing the shaft cylinder 2, a protruding spherical portion 41 for locking is formed so that the article held by the clip member 40 does not come off. On the outer surface of the clip member 40 from the center in the longitudinal direction to the rear end portion, a second recess 42 extending in the longitudinal direction is formed so as to accommodate the leaf spring 30. On the bottom surface of the second recess 42, an insertion groove 43 extending in the longitudinal direction of the clip member 40 and wider than between the side walls of the second recess 42 is formed. In other words, the insertion groove 43 is a groove provided in each of the side walls near the bottom surface of the second recess 42. The insertion groove 43 is open at the rear end side of the clip member 40. The second recess 42 is bent inward by approximately 90 degrees at the rear end portion of the clip member 40. A support surface 44 facing inward is formed at the rear end portion of the clip member 40 defined by the second recess 42.

[0028] The assembly of the clip member 40 to the rear shaft 10 will be described. The clip member 40 is arranged with respect to the rear shaft 10 such that the rear end portion of the clip member 40 is received in the notch portion 11 of the rear shaft 10 and locked to the rear end surface 12a of the rectangular protrusion 12. Next, the leaf spring 30 is arranged so as to sandwich the rear shaft 10 and the clip member 40. That is, the leaf spring 30 is moved from the rear to the front of the rear shaft 10 and the clip member 40, the first protruding piece 31 is arranged in the first recess 13 of the rear shaft 10, and the second protruding piece 32 of the leaf spring 30 is inserted into the insertion groove 43 of the clip member 40.

[0029] The width of the first recess 13 of the rear shaft 10 is slightly smaller than the width of the first protruding piece 31 of the received leaf spring 30. Therefore, the first protruding piece 31 of the leaf spring 30 is loosely fitted into the first recess 13 of the rear shaft 10. Therefore, with respect to the rear shaft 10, the first protruding piece 31 can be pulled out of the first recess 13 along the axial direction, or a force can be applied to the first protruding piece 31 in a direction orthogonal to the axial direction to remove it from the first recess 13. As a result, the rear shaft 10 and the leaf spring 30 can be easily disassembled.

[0030] The width of the insertion groove 43 of the clip member 40 is slightly smaller than the width of the second protruding piece 32 of the receiving leaf spring 30. Therefore, the second protruding piece 32 of the leaf spring 30 fits loosely into the insertion groove 43 of the clip member 40. Thus, the second protruding piece 32 can be pulled out along the insertion groove 43, and the clip member 40 and the leaf spring 30 can be easily disassembled. On the other hand, the second protruding piece 32 cannot be removed in a direction orthogonal to the insertion groove 43.

[0031] Next, the assembly of the rear shaft 10 with the clip member 40 attached, the inner cylinder 20, and the front shaft 3 will be described with reference to FIGS. 7 to 9. FIG. 7 is an exploded perspective view of the rear shaft 10 and the inner cylinder 20 of the writing instrument 1 in FIG. 1, FIG. 8 is an exploded perspective view of the front shaft 3 and the rear shaft 10 of the writing instrument 1 in FIG. 1, and FIG. 9 is a longitudinal sectional view of the rear part of the writing instrument 1 in FIG. 1.

[0032] Referring to FIG. 7, the inner cylinder 20 in which the rotor 6 and the operating member 7 are disposed inside is inserted from the rear end opening of the rear shaft 10 to which the clip member 40 is attached as described above. At this time, the rotational position around the central axis of the inner cylinder 20 is determined so that the rear end portion of the clip member 40 is received in the receiving portion 23 of the inner cylinder 20. When the inner cylinder 20 is inserted to the innermost part inside the rear shaft 10, the rear end portion of the clip member 40 is received in the receiving portion 23 of the inner cylinder 20. Further, the annular protrusion 28 formed on the side surface of the inner cylinder 20 gets over each of the plurality of locking protrusions 15 formed on the inner surface of the rear shaft 10, and the rear shaft 10 and the inner cylinder 20 can be locked in the axial direction. At the same time as the annular protrusion 28 gets over the plurality of locking protrusions 15, the rear end surface of the rear shaft 10 and the front end surface of the flange portion 22 of the inner cylinder 20 come into contact with each other, and the rear shaft 10 and the inner cylinder 20 are fitted together. The rear end surface 12a of the rectangular protrusion 12 of the rear shaft 10 and the front end surfaces of the two protrusions 23b of the receiving portion 23 are in contact. The overall length of the inner cylinder 20 is longer than the overall length of the rear shaft 10. Therefore, in a state where the rear shaft 10 and the inner cylinder 20 are fitted together, the front end portion of the inner cylinder 20, particularly the male screw portion 21, protrudes from the front end portion of the rear shaft 10.

[0033] The diameter of the circumscribed circle around the central axis of the inner cylinder 20 of the two circular protrusions 27 formed on the side surface of the inner cylinder 20 is formed to be slightly larger than the inner diameter of the rear shaft 10. Therefore, when the inner cylinder 20 is inserted into the rear shaft 10, the circular protrusions 27 of the inner cylinder 20 are pressed radially inward by the inner surface of the rear shaft 10. Thereby, the elastic deformation portion 26 of the inner cylinder 20 elastically deforms so as to protrude radially inward more than the other inner surfaces of the inner cylinder 20. As a result, even when the front shaft 3 is removed for replacing the refill 4 or the like in the writing instrument 1, the front end portion of the rotor 6 disposed in the inner cylinder 20 is locked to the rear end portion of the elastic deformation portion 26, and the rotor 6 and the operation member 7 are prevented from falling due to gravity.

[0034] Next, as shown in FIG. 8, the rear shaft 10 and the inner cylinder 20 are inserted from the rear end opening of the front shaft 3 in which the refill 4 and the spring 5 are disposed, and the male screw portion 21 of the inner cylinder 20 is screwed into the female screw portion 3a of the front shaft 3, thereby completing the assembly of the writing instrument 1.

[0035] As shown in FIG. 9, in a state where the rear shaft 10 and the inner cylinder 20 are integrally attached, the first protruding piece 31 which is the clamping portion of the leaf spring 30 is clamped by the inner surface of the rear shaft 10 and the outer surface of the inner cylinder 20. Specifically, the first protruding piece 31 of the leaf spring 30 is clamped between the first clamping surface 14 of the rear shaft 10 and the second clamping surface 24 of the inner cylinder 20. In other words, the distance between the first clamping surface 14 and the second clamping surface 24, or the thickness of the first protruding piece 31 is determined so that the first protruding piece 31 is clamped without loosening.

[0036] The first tab 31 is clamped between the inner surface of the rear shaft 10 and the outer surface of the inner cylinder 20, and the second tab 32 fits into the insertion groove 43 of the clip member 40, so that the clip member 40 can be opened and closed to grip an article. That is, when lifting the front end portion of the clip member 40 to open the clip member 40, the support portion 35 of the leaf spring 30 serves as a fulcrum with respect to the second clamping surface 24 of the inner cylinder 20, and the leaf spring 30 elastically deforms about the connecting portion 33 and the bent portion 34. Thereby, the clip member 40 can grip an article. At this time, the support surface 44 of the clip member 40 supports the vicinity of the bent portion 34 of the leaf spring 30, so that it can be elastically deformed stably. When the clip member 40 opens, a rearward force acts on the clip member 40. The rearward movement of the clip member 40 is restricted by the rear end portion of the clip member 40 abutting against the front end surface 23a of the receiving portion 23. Further, since the rear end portion of the clip member 40 is formed in an arc shape, even when the clip member 40 abuts against the front end surface 23a of the receiving portion 23 when the clip member 40 opens, the frictional resistance is small.

[0037] Next, the disassembly of the writing instrument 1 will be described. The disassembly of the writing instrument 1 is the reverse of the above-described assembly procedure. That is, when gripping the front shaft 3 with one hand and gripping and rotating the rear shaft 10 or the clip member 40 with the other hand to release the screwing engagement between the front shaft 3 and the inner cylinder 20, the state shown in FIG. 8 is obtained. For example, the replacement of the refill 4 is performed in this state. At this time, as described above, the rotor 6 and the operation member 7 are engaged with the elastic deformation portion 26 and do not fall off. Further, the clip member 40 is attached to the rear shaft 10 or the inner cylinder 20 by the first tab 31 of the leaf spring 30 being clamped between the inner surface of the rear shaft 10 and the outer surface of the inner cylinder 20, and does not fall off.

[0038] Next, when gripping the rear shaft 10 with one hand and gripping the inner cylinder 20 with the other hand and pulling out the inner cylinder 20 from the rear shaft 10, the state shown in FIGS. 5 and 6 is obtained. As described above, since the first projecting piece 31 of the leaf spring 30 is loosely fitted to the first recess 13 of the rear shaft 10, as described above, the rear shaft 10 and the leaf spring 30 can be easily disassembled. The clip member 40 and the leaf spring 30 can be easily disassembled by pulling out the second projecting piece 32 of the leaf spring 30 along the insertion groove 43 of the clip member 40, that is, along the axial direction. Further, when the inner cylinder 20 is pulled out from the rear shaft 10, the elastic deformation of the elastic deformation portion 26 is restored. As a result, it becomes possible to take out the rotor 6 and the operation member 7 disposed inside the inner cylinder 20.

[0039] From the above, according to the writing instrument 1 according to the first embodiment, intended disassembly is facilitated while preventing unintentional disassembly. Thereby, the leaf spring 30 formed of a metal material and other parts such as the shaft cylinder 2 formed of a resin material can be separated and recycled or discarded. Furthermore, since each part formed of a resin material can be easily disassembled, sorting according to the resin type and recycling or discarding thereby can be performed. Also, while disassembly is easy, assembly is also easy as described above. Therefore, when a certain part is damaged, only the damaged part can be replaced and the other parts can be reused for assembly. For example, when the clip member 40 is damaged, only the clip member 40 can be easily replaced.

[0040] FIG. 10 is a perspective view of a writing instrument 100 according to a second embodiment of the present invention, and FIG. 11 is a longitudinal sectional view of the writing instrument 100 of FIG. 10. The writing instrument 100 is a so-called knock-type writing instrument.

[0041] In the writing instrument 1 according to the above-described first embodiment, the clip member 40 is attached to the shaft cylinder 2 via the leaf spring 30. In the writing instrument 100 according to the second embodiment, the leaf spring 30 itself functions as a clip member, and an article can be gripped without using a separate member such as the clip member 40 described above. Therefore, the writing instrument 100 has a different configuration of the rear shaft, the inner cylinder, and the leaf spring compared to the writing instrument 1 described above. Therefore, the writing instrument 100 will be mainly described centering on the parts different from the writing instrument 1.

[0042] The writing instrument 100 includes a shaft cylinder 102 having a front shaft 3, a rear shaft 110 disposed behind the front shaft 3, and an inner cylinder 120 disposed through the rear shaft 110, a refill 4 which is a writing body disposed within the shaft cylinder 102 and having a writing portion 4a at one end, and a spring 5 which is an elastic member for biasing the refill 4 rearward. A leaf spring 130 functioning as a clip member is attached to the side surface of the shaft cylinder 2. A known knock mechanism is disposed inside the rear end portion of the shaft cylinder 102. The knock mechanism has a rotor 6 disposed movably in the front-rear direction, and an operation member 7 protruding rearward from the rear end opening of the shaft cylinder 102 and disposed behind the rotor 6 and movably in the front-rear direction. The rotor 6 and the operation member 7 are biased rearward together with the refill 4 by the spring 5.

[0043] FIG. 12 is a perspective view of the inner cylinder 120 of the writing instrument 100 in FIG. 10, and FIG. 13 is a longitudinal sectional view of the inner cylinder 120 of the writing instrument 100 in FIG. 10.

[0044] The inner cylinder 120 is a cylindrical member. Similar to the inner cylinder 20 of the writing instrument 1, the inner cylinder 120 has an outer cam 8, a male screw portion 21, a U-shaped hole 25, an elastically deformable portion 26, a circular protrusion 27, and an annular protrusion 28. A flange portion 122 is formed on the outer surface of the rear end portion of the inner cylinder 120. The flange portion 122 has an annular front end surface 122a. A second clamping surface 124 is formed extending from a part of the front end surface 122a of the flange portion 122 to the front end portion of the inner cylinder 120 and corresponding to a first clamping surface 114 described later. The second clamping surface 124 is formed in a rectangular shape as if shaving off the side surface of the cylindrical inner cylinder 120.

[0045] FIG. 14 is an exploded longitudinal sectional view of the rear shaft 110 and the leaf spring 130 of the writing instrument 100 in FIG. 10, FIG. 15 is an exploded perspective view of the rear shaft 110 and the leaf spring 130 of the writing instrument in FIG. 10, and FIG. 16 is a sectional perspective view of the rear shaft 110 and the leaf spring 130 of the writing instrument in FIG. 10.

[0046] The rear shaft 110 is a cylindrical member. A rectangular notch 111 is formed at the rear end portion of the rear shaft 110. On the inner surface in front of the notch 111, a first recess 113 which is a receiving recess extending in the axial direction is formed. The first recess 113 is formed by utilizing the wall thickness of the rear shaft 110. That is, each of the outer surface of the rear shaft 110 corresponding to the first recess 113 and the inner surface of the rear shaft 110 in the vicinity of the first recess 113 is formed flush with other portions. The first recess 113 is formed in a substantially rectangular shape. A first clamping surface 114 is formed on the bottom surface of the first recess 113. A fitting portion 116 having a narrower width in the circumferential direction than the rear portion is formed in the front portion of the first recess 113. Four locking protrusions 15 are formed at equal intervals along the circumferential direction on the inner surface of the front end portion of the rear shaft 110.

[0047] The leaf spring 130 is an elastic plate-like member. The leaf spring 130 is formed of a metal material, for example, a stainless steel material, but may be formed of a resin material. The leaf spring 130 is formed by bending an elongated substantially rectangular plate-like member so as to have a substantially U-shaped opening toward the front. The leaf spring 130 has a first protruding piece 131, a second protruding piece 132, and a connecting portion 133 connecting the first protruding piece 131 and the second protruding piece 132.

[0048] The connecting portion 133 has a right-angled portion 136 that is connected to the first protruding piece 131 at a substantially right angle, and a curved portion 137 that is connected to the second protruding piece 132 in an arc shape with a central angle of approximately 90 degrees. The first protruding piece 131 and the second protruding piece 132 extend in the same direction and are substantially parallel. The first protruding piece 131 is shorter than the second protruding piece 132. On both side surfaces in the width direction of the first protruding piece 131, saw blade-shaped saw blade protrusions 138 are formed. On the inner surface of the front end portion of the leaf spring 130 in the assembled state, that is, on the side facing the shaft cylinder 102, a protruding ball portion 139 is formed to lock the article held by the leaf spring 130 so that it does not come off.

[0049] The assembly of the leaf spring 130 to the rear shaft 110 will be described. The first protruding piece 131 of the leaf spring 130 is inserted into the first recess 113 from the rear of the rear shaft 110 along the axial direction. At this time, the first protruding piece 131 advances while the looser inclined surface of the saw blade protrusions 138 on both side surfaces of the first protruding piece 131 expands the fitting portion 116 in the width direction. In other words, the width of the fitting portion 116 in the first recess 113 is determined to be smaller than the width of the first protruding piece 131 at the portion where the saw blade protrusions 138 are provided. As a result, the saw blade protrusions 138 bite into the fitting portion 116 by deforming the fitting portion 116, so that the first protruding piece 131 fits into the first recess 113. Also, the connecting portion 133 of the leaf spring 130 is received in the notch portion 111 of the rear shaft 110.

[0050] Next, the assembly of the rear shaft 110 to which the leaf spring 130 is attached, the inner cylinder 120, and the front shaft 3 will be described with reference to FIGS. 17 to 19. FIG. 17 is an exploded perspective view of the rear shaft 110 and the inner cylinder 120 of the writing instrument 100 in FIG. 10, FIG. 18 is an exploded perspective view of the front shaft 3 and the rear shaft 110 of the writing instrument 100 in FIG. 10, and FIG. 19 is a longitudinal sectional view of the rear portion of the writing instrument 100 in FIG. 10.

[0051] Referring to FIG. 17, as described above, the inner cylinder 120 in which the rotor 6 and the operating member 7 are disposed inside is inserted from the rear end opening of the rear shaft 110 to which the leaf spring 130 is attached. At this time, the rotational position around the central axis of the inner cylinder 120 is determined so that the leaf spring 130 and the second clamping surface 124 of the inner cylinder 120 are aligned in the rotational direction. When the inner cylinder 120 is inserted to the innermost part inside the rear shaft 110, the annular protrusion 28 formed on the side surface of the inner cylinder 120 gets over each of the plurality of locking protrusions 15 formed on the inner surface of the rear shaft 110, and the rear shaft 110 and the inner cylinder 120 can be locked in the axial direction. At the same time as the annular protrusion 28 gets over the plurality of locking protrusions 15, the rear end surface of the rear shaft 110 and the front end surface 122a of the flange portion 122 of the inner cylinder 120 come into contact with each other, and the rear shaft 110 and the inner cylinder 120 are fitted together. The overall length of the inner cylinder 120 is longer than the overall length of the rear shaft 110. Therefore, in a state where the rear shaft 110 and the inner cylinder 120 are fitted together, the front end portion of the inner cylinder 120, particularly the male screw portion 21, protrudes from the front end portion of the rear shaft 110. Note that the front end portion of the rotor 6 disposed inside the inner cylinder 120 is locked to the rear end portion of the elastic deformation portion 26 as described above, and the rotor 6 and the operating member 7 are prevented from falling off due to gravity.

[0052] Next, as shown in FIG. 18, the rear shaft 110 and the inner cylinder 120 are inserted from the rear end opening of the front shaft 3 in which the refill 4 and the spring 5 are disposed, and the male screw portion 21 of the inner cylinder 120 is screwed into the female screw portion 3a of the front shaft 3, thereby completing the assembly of the writing instrument 100.

[0053] As shown in FIG. 19, in a state where the rear shaft 110 and the inner cylinder 120 are integrally attached, the first protruding piece 131 which is the clamping portion of the leaf spring 130 is clamped by the inner surface of the rear shaft 110 and the outer surface of the inner cylinder 120. Specifically, the first protruding piece 131 of the leaf spring 130 is clamped between the first clamping surface 114 of the rear shaft 110 and the second clamping surface 124 of the inner cylinder 120. In other words, the distance between the first clamping surface 114 and the second clamping surface 124, or the thickness of the first protruding piece 131 is determined so that the first protruding piece 131 is clamped without loosening.

[0054] When the first tab 131 is clamped by the inner surface of the rear shaft 110 and the outer surface of the inner cylinder 120, the leaf spring 130 can be opened and closed to grip an article. That is, when lifting the front end portion of the leaf spring 130 to open the leaf spring 130, the right-angle portion 136 of the leaf spring 130 serves as a fulcrum with respect to the second clamping surface 124 of the inner cylinder 120, and the leaf spring 130 is elastically deformed about the curved portion 137. Thereby, the leaf spring 130 can grip an article. When the leaf spring 130 opens, a rearward force acts on the leaf spring 130. The rearward movement of the leaf spring 130 is restricted by the contact of the right-angle portion 136, which is the rear end portion of the leaf spring 130, with the front end surface 122a of the flange portion 122.

[0055] Next, the disassembly of the writing instrument 100 will be described. The disassembly of the writing instrument 100 is the reverse of the above-described assembly procedure. That is, when gripping the front shaft 3 with one hand and gripping and rotating the rear shaft 110 or the leaf spring 130 with the other hand to release the screwing engagement between the front shaft 3 and the inner cylinder 120, the state shown in FIG. 18 is obtained. For example, the replacement of the refill 4 is performed in this state. At this time, as described above, the rotor 6 and the operation member 7 are engaged with the elastic deformation portion 26 and do not fall off. Further, the leaf spring 130 is attached to the rear shaft 110 or the inner cylinder 120 by the first tab 131 being clamped by the inner surface of the rear shaft 110 and the outer surface of the inner cylinder 120, and does not fall off.

[0056] Next, when gripping the rear shaft 110 with one hand and gripping the inner cylinder 120 with the other hand and pulling out the inner cylinder 120 from the rear shaft 110, the state shown in FIGS. 14 and 15 is obtained. As described above, the first tab 131 of the leaf spring 130 has the saw blade protrusion 138 biting into the fitting portion 116 of the first recess 113 of the rear shaft 110. Therefore, although the first tab 131 of the leaf spring 130 cannot be pulled out of the first recess 113 along the axial direction with respect to the rear shaft 110, it can also be removed from the first recess 113 by applying a force in a direction orthogonal to the axial direction to the first tab 131. As a result, the rear shaft 110 and the leaf spring 130 can be easily disassembled. At this time, the fitting portion 116 of the first recess 113 is damaged by the removal of the saw blade protrusion 138.

[0057] As described above, according to the writing instrument 100 according to the second embodiment, intended disassembly is facilitated while preventing unintentional disassembly. As a result, the leaf spring 130 formed of a metal material and other components such as the shaft cylinder 102 formed of a resin material can be separated and recycled or discarded. Furthermore, since each component formed of a resin material can be easily disassembled, sorting according to the resin type and recycling or discarding accordingly can be performed. Note that according to the writing instrument 100, the first recess 113 of the rear shaft 110 is damaged when the leaf spring 130 is disassembled, so the rear shaft 110 cannot be reused, but the leaf spring 130 and other components can be reused for assembly.

[0058] In the above-described embodiment, the rear shaft of the writing instrument is used as the first cylindrical member, the inner cylinder is used as the insertion member inserted into the inside from the first opening end of the first cylindrical member, the clip member and the leaf spring are used as the additional members, and the first end of the leaf spring is used as the clamping portion of the additional member. The assembly and disassembly of these were described. In short, since the clamping portion is compressed in the radial direction by the insertion of the insertion member into the first cylindrical member, the additional member is firmly fixed by the frictional resistance between the inner surface of the first cylindrical member and one surface of the clamping portion, and the frictional resistance between the outer surface of the insertion member and the other surface of the clamping portion.

[0059] The above-described configuration may be applied to any first cylindrical member, any insertion member, and any additional member in the writing instrument as long as the clamping portion of the additional member is clamped by the inner surface of the first cylindrical member and the outer surface of the insertion member. For example, the first cylindrical member may be the front shaft, the insertion member may be the rear shaft, and the additional member may be a member for advertising that is clamped by the inner surface of the front shaft and the outer surface of the rear shaft. Further, the above-described configuration may be applied to writing instruments other than knock-type writing instruments, such as cap-type writing instruments.

[0060] In the above-described embodiment, the rear shaft, which is the first cylindrical member, and the inner cylinder, which is the insertion member, were cylindrical, but they may be cylindrical members with a polygonal cross-section or corresponding insertion members. Although the first recess was provided as a receiving recess for receiving the first end portion of the leaf spring on the inner surface of the rear shaft, which is the first cylindrical member, a receiving recess may be provided on the outer surface of the inner cylinder, which is the insertion member. Further, without providing a receiving recess in either the first cylindrical member or the insertion member, the first support surface and the second support surface may be used to sandwich the clamping portion of the additional member. The additional member may be a clip member or a part of a clip member. The front shaft may be used as the second cylindrical member, or the front shaft and the rear shaft may be used as the first cylindrical member. The additional member may be formed of a material different from that of the first cylindrical member, or may be formed of the same or a similar material. A part or all of the additional member may be formed of a metal material, and the first cylindrical member may be formed of a resin material.

Explanation of Signs

[0061] 1 Writing instrument 2 Shaft cylinder 3 Front shaft 4 Refill 5 Spring 6 Rotor 7 Operating member 10 Rear shaft 11 Notch 13 First recess 14 First clamping surface 15 Locking projection 20 Inner cylinder 22 Flange portion 23 Receiving portion 24 Second clamping surface 31 First projecting piece 32 Second projecting piece 33 Connecting portion 34 Bent portion 35 Support portion 40 Clip member 42 Second recess 43 Insertion groove 44 Support surface

Claims

1. A writing instrument comprising a first tubular member, an insertion member inserted into the first opening end of the first tubular member, and an additional member having a clamping portion clamped between the inner surface of the first tubular member and the outer surface of the insertion member.

2. A writing instrument as described in claim 1, wherein a receiving recess capable of receiving the clamping portion is provided on the inner surface of the first tubular member or the outer surface of the insertion member, and the clamping portion and the receiving recess are formed so that the clamping portion fits into the receiving recess.

3. 3. The writing instrument as described in claim 1 or 2, further comprising a second tubular member connected to a second open end of the first tubular member, the first tubular member being a rear barrel and the second tubular member being a front barrel.

4. 3. The writing implement according to claim 1, wherein a part or the whole of the additional member is made of a metal material, and the first cylindrical member is made of a resin material.

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