Telescopic writing tool

Abstract

The pen comprises a pen holder (2); and a writing body (3) accommodated in the barrel (2) so as to be movable in the front-back direction. A tip (31) is provided at the tip of the writing body (3), and the tip (31) is disposed so as to be retractable from a tip hole (21) of the barrel (2). An annular support part (4) for supporting the outer peripheral surface of the writing body (3) is provided on the inner peripheral surface of the barrel (2). The annular support section (4) is provided with a support section that supports the outer peripheral surface of the writing body (3). The support portion is movable in the diameter-expanding direction or the front-back direction by contact with the outer peripheral surface of the writing body (3). The annular support part (4) is locally provided with an elastic deformation part which can be elastically deformed preferentially over other parts of the annular support part (4) when the outer peripheral surface of the writing body (3) is in contact with the support part.

Description

Technical Field

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

[0002] This application claims priority to Japanese Patent Application No. 2022-202020 filed in Japan on December 19, 2022, and Japanese Patent Application No. 2023-121589 filed in Japan on July 26, 2023, the contents of which are incorporated herein by reference. Background Art

[0003] Patent Document 1 discloses a vibration-proof device for a writing tip. This device comprises an elastic ring having an inner diameter slightly smaller than the outer diameter of the writing tip, which acts as a structure for preventing the writing tip from shaking during writing and engages with a locking step provided in the top end of a pen barrel.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Utility Model Application Laid-Open No. 5-93884 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] With the structure of Patent Document 1, if dimensional deviation occurs in the inner diameter of the elastic ring or the outer diameter of the writing tip, the dimensional deviation may not be sufficiently absorbed by the elastic deformation of the elastic ring alone.

[0009] In Patent Document 1, for example, if the elastic ring is tightly pressed against the writing tip, the sliding resistance between the elastic ring and the outer surface of the writing tip increases when the writing tip is extended or retracted, thereby preventing the writing tip from smoothly retracting or retracting. Furthermore, for example, if the elastic ring is not in sufficient contact with the outer surface of the writing tip, a sufficient anti-vibration effect of the ballpoint pen tip (pen tip) during writing may not be obtained. That is, with the structure of Patent Document 1, if dimensional deviations occur in the inner diameter of the elastic ring or the outer diameter of the writing tip, both a smooth retracting or retracting action of the writing tip and a sufficient anti-vibration effect of the writing tip during writing may not be simultaneously achieved.

[0010] The invention of the present application is an invention for solving the above-mentioned existing problems, and it aims to provide a retractable writing instrument that can simultaneously obtain both a smooth telescopic movement of the nib and a sufficient anti-vibration effect of the writing body during writing even when there are dimensional deviations in the outer diameter of the writing body, dimensional deviations in the inner diameter of the inner peripheral surface of the pen barrel on which the outer peripheral surface of the writing body slides (i.e., the inner diameter of the annular support portion), or either of the two. In the invention of the present application, "front" refers to the nib side, and "rear" refers to the side opposite to the nib side. The definition of the direction of the invention of the present application will be described separately later.

[0011] An example of the above problem is shown below. That is, for example, a retractable writing instrument is to be provided that can simultaneously obtain both a smooth telescopic movement of the nib and a sufficient anti-vibration effect of the nib during writing even when there are dimensional deviations in either or both of the outer diameter of the front end portion of the writing body and the inner diameter of the inner peripheral surface of the telescopic hole on which the outer peripheral surface of the front end portion of the writing body slides.

[0012] Solution to the problem

[0013] A first aspect of the present invention is a retractable writing instrument, characterized by comprising: a pen barrel; and a writing body accommodated in the pen barrel so as to be movable in the front-rear direction, a nib being provided at the front end portion of the writing body, the nib being configured to be able to telescopically extend from the front end hole of the pen barrel, an annular support portion for supporting the outer peripheral surface of the writing body being provided on the inner peripheral surface of the pen barrel, the annular support portion having a support portion for supporting the outer peripheral surface of the writing body, the support portion being able to move in the diameter-expanding direction or the front-rear direction by contact with the outer peripheral surface of the writing body, and the annular support portion partially having an elastic deformation portion that can preferentially elastically deform relative to other portions of the annular support portion when the outer peripheral surface of the writing body comes into contact with the support portion.

[0014] According to the retractable writing instrument of the first aspect, even when there are dimensional deviations in either or both of the outer diameter of the outer peripheral surface of the writing body and the inner diameter of the inner peripheral surface of the pen barrel on which the outer peripheral surface of the writing body slides (i.e., the inner diameter of the support portion of the annular support portion), the following effects can be obtained. That is, the sliding resistance between the outer peripheral surface of the writing body and the support portion is reduced, so that a smooth telescopic movement of the nib can be obtained. And during writing, the support portion stably supports the outer peripheral surface of the writing body, so that a sufficient anti-vibration effect of the writing body during writing can be obtained.

[0015] It should be noted that in the first aspect of the present invention, the inner peripheral surface of the pen barrel may, for example, be the inner peripheral surface of the front end hole of the pen barrel, the inner peripheral surface of the middle portion of the pen barrel, etc.

[0016] It should be noted that in the first aspect of the present invention, the outer peripheral surface of the writing body can be, for example, the outer peripheral surface of a pen tip such as a ballpoint pen tip, the outer peripheral surface of a tip holder that holds the tip, or the outer peripheral surface of an ink cartridge having a tip.

[0017] It should be noted that in the first aspect of the present invention, for example, a ring-shaped support portion can be cited as a configuration in which the ring-shaped support portion is fixed to the inner peripheral surface of the pen barrel as a separate member or a configuration in which the ring-shaped support portion is integrally formed on the inner peripheral surface of the pen barrel (that is, a configuration in which the ring-shaped support portion and the inner peripheral surface of the pen barrel are integrally formed of the same material). It should be noted that the ring-shaped support portion can also be renamed as a ring-shaped support structure or the like.

[0018] The second aspect of the present invention is a telescopic writing instrument according to the first aspect, wherein the ring-shaped support portion includes: a base portion disposed on the inner peripheral surface of the pen barrel; a plurality of the elastic deformation portions extending inward from the base portion; and the support portion provided at the inner end of the elastic deformation portion, and each of the elastic deformation portions is formed to extend in a direction deviating from the central direction of the ring-shaped support portion, and when the outer peripheral surface of the writing body contacts the support portion, each of the elastic deformation portions tilts radially outward.

[0019] According to the telescopic writing instrument of the second aspect, when the outer peripheral surface of the writing body contacts the support portion, the support portion expands and deforms (moves in the diameter-expanding direction) with a small force. Therefore, the contact resistance between the outer peripheral surface of the writing body and the support portion is reduced, and a smooth telescopic movement of the pen tip can be obtained more reliably.

[0020] It should be noted that in the second aspect of the present invention, each of the elastic deformation portions being formed to extend in a direction deviating from the central direction of the ring-shaped support portion means that the center of the ring-shaped support portion does not exist on the extension line of the virtual straight line connecting the center of the inner ends of the elastic deformation portions and the center of the outer ends of the elastic deformation portions.

[0021] The third aspect of the present invention is a telescopic writing instrument according to the second aspect, wherein an inner notch that opens inward is provided on the inner side of the elastic deformation portion, a plurality of the support portions are circumferentially and dispersedly arranged, an outer notch that opens outward is provided on the outer side of the elastic deformation portion, and a plurality of the base portions are circumferentially and dispersedly arranged.

[0022] According to the telescopic writing instrument of the third aspect, when the outer peripheral surface of the writing body contacts the support portion, the support portion expands and deforms (moves in the diameter-expanding direction) with a small force. Therefore, the contact resistance between the outer peripheral surface of the writing body and the support portion is reduced, and a smooth telescopic movement of the pen tip can be obtained more reliably.

[0023] A fourth aspect of the present invention is the retractable writing instrument of the second aspect, wherein the support portion extends circumferentially in a manner that connects the inner ends of adjacent elastic deformation portions to each other, and the base portion extends circumferentially in a manner that connects the outer ends of adjacent elastic deformation portions to each other.

[0024] According to the retractable writing instrument of the fourth aspect, the writing body can be further stably supported by the support portion, thereby further preventing the writing body from shaking during writing.

[0025] A fifth aspect of the present invention is the retractable writing instrument of the fourth aspect, wherein a plurality of inner notches are locally provided in a manner that does not connect the inner ends of adjacent elastic deformation portions to each other, a plurality of support portions are circumferentially and dispersedly arranged, a plurality of outer notches are locally provided in a manner that does not connect the outer ends of adjacent elastic deformation portions to each other, and a plurality of base portions are circumferentially and dispersedly arranged.

[0026] According to the retractable writing instrument of the fifth aspect, the writing body can be further stably supported by the support portion, thereby further preventing the writing body from shaking during writing. In addition, when the outer peripheral surface of the writing body contacts the support portion, the support portion expands and deforms (moves in the diameter-expanding direction) with a smaller force. Therefore, the contact resistance between the outer peripheral surface of the writing body and the support portion is reduced, and a smooth telescopic movement of the nib can be further reliably obtained.

[0027] A sixth aspect of the present invention is the retractable writing instrument of the fourth aspect, wherein the support portion is formed in a ring shape, and the base portion is formed in a ring shape.

[0028] According to the retractable writing instrument of the sixth aspect, the periphery of the writing body can be stably supported by the support portion, thereby reliably preventing the writing body from shaking during writing.

[0029] A seventh aspect of the present invention is the retractable writing instrument of the third aspect, wherein the inner end of each elastic deformation portion is connected to the circumferential one end of each support portion, the circumferential other end of each support portion is connected to the circumferential one end of each base portion, and the circumferential other end of each base portion is connected to the outer end of each elastic deformation portion.

[0030] According to the retractable writing instrument of the seventh aspect, the circumferential one end of each support portion preferentially expands and deforms (moves in the diameter-expanding direction). Therefore, the circumferential other end of each support portion can stably support the writing body, thereby further preventing the writing body from shaking during writing.

[0031] The eighth aspect of the present invention is the retractable writing instrument of the second aspect, wherein the base is formed in a ring shape, the outer ends of the respective elastic deformation portions are connected to the base, the inner ends of the respective elastic deformation portions are all separated from each other, and the inner ends of the respective elastic deformation portions constitute the support portion.

[0032] In the retractable writing instrument according to the eighth aspect, when the outer peripheral surface of the writing body comes into contact with the support portion, the support portion expands and deforms (moves in the direction of increasing diameter) with a small force. Therefore, the contact resistance between the outer peripheral surface of the writing body and the support portion is reduced, and thus a smooth telescopic movement of the nib can be reliably obtained.

[0033] The ninth aspect of the present invention is the retractable writing instrument of the first aspect, wherein the ring-shaped support portion includes at least one support portion that is C-shaped when viewed in the front view and is connected to the inner peripheral surface of the pen barrel, and the elastic deformation portion is provided to connect the ends of the support portion, and the elastic deformation portion can be elastically deformed in the circumferential direction.

[0034] In the retractable writing instrument according to the ninth aspect, when the outer peripheral surface of the writing body comes into contact with the support portion, the support portion expands and deforms (moves in the direction of increasing diameter) with a small force. Therefore, the contact resistance between the outer peripheral surface of the writing body and the support portion is reduced, and thus a smooth telescopic movement of the nib can be reliably obtained.

[0035] It should be noted that in the ninth aspect, there is provided one or more support portions that are C-shaped when viewed in the front view. When there is a single support portion that is C-shaped when viewed in the front view, both ends of the support portion are connected by a single elastic deformation portion. When there are multiple support portions that are C-shaped when viewed in the front view, there are provided the same number of elastic deformation portions as that of the support portion, and each elastic deformation portion is connected between the respective support portions.

[0036] The tenth aspect of the present invention is the retractable writing instrument of the first aspect, wherein the ring-shaped support portion is integrally formed on the inner peripheral surface of the pen barrel.

[0037] In the retractable writing instrument according to the tenth aspect, the ring-shaped support portion and the inner peripheral surface of the pen barrel are integrally formed of the same member. Therefore, the number of components of the retractable writing instrument can be reduced, and thus the manufacturing cost can be lowered. In addition, there is no need for the operation of assembling the ring-shaped support portion to the inner peripheral surface of the pen barrel, and thus it is easy to manufacture.

[0038] The eleventh aspect of the present invention is a telescopic writing instrument according to the first aspect, wherein a plurality of convex portions are provided on the inner peripheral surface of the pen barrel in the circumferential direction, each of the convex portions protrudes radially inward from the inner peripheral surface of the pen barrel, each of the convex portions can be elastically deformed, and in a state where the nib protrudes outward from the front end hole, the top of each of the convex portions is in contact with the outer peripheral surface of the writing body, and the inner peripheral surface of the pen barrel between adjacent convex portions and the outer peripheral surface of the writing body are in a non-contact state. The annular support portion has the plurality of convex portions, the support portion is disposed at the top of each of the convex portions, and the elastic deformation portion is disposed radially outward of the support portion of each of the convex portions.

[0039] According to the telescopic writing instrument of the eleventh aspect, even when there are dimensional deviations in both or either one of the outer diameter of the writing body (for example, the outer diameter of the front end portion of the writing body) and the inner diameter of the inner peripheral surface of the pen barrel (for example, the inner peripheral surface of the front end hole) on which the outer peripheral surface of the writing body (for example, the outer peripheral surface of the front end portion of the writing body) slides (that is, the diameter of the virtual inscribed circle tangent to the top of each convex portion), the following effects can be obtained. That is, the sliding resistance between the outer peripheral surface of the writing body (for example, the outer peripheral surface of the front end portion of the writing body) and each convex portion is reduced, so that a smooth telescopic movement of the nib can be obtained. In addition, the outer peripheral surface of the writing body (for example, the outer peripheral surface of the front end portion of the writing body) is stably supported by the top of each convex portion in the state where the nib protrudes, so that a sufficient anti-vibration effect of the nib during writing can be obtained.

[0040] In particular, according to the telescopic writing instrument of the eleventh aspect, each convex portion protrudes radially inward from the inner peripheral surface of the pen barrel (for example, the inner peripheral surface of the front end hole), so that the top of each convex portion in the state where the nib protrudes can stably support the outer peripheral surface of the writing body (for example, the outer peripheral surface of the front end portion of the writing body) for a long time.

[0041] It should be noted that in the eleventh aspect of the present invention, the outer peripheral surface of the writing body refers to, for example, the outer peripheral surface of a ballpoint pen nib or the like, the outer peripheral surface of a nib holder that holds the nib, or the outer peripheral surface of an ink cartridge having a nib. In addition, the outer peripheral surface of the front end portion of the writing body refers to, for example, the outer peripheral surface of the nib, the outer peripheral surface of the nib holder, or the outer peripheral surface of the front end portion of the ink cartridge.

[0042] The twelfth aspect of the present invention is a telescopic writing instrument according to the eleventh aspect, wherein the top of each of the convex portions has a convex curved surface shape in a longitudinal section.

[0043] In the telescopic writing instrument according to the twelfth aspect, the outer peripheral surface of the writing body (for example, the outer peripheral surface of the front end portion of the writing body) contacts the top portions of the respective convex portions in a dot-like or circumferentially linear manner. The contact resistance between the outer peripheral surface of the writing body (for example, the outer peripheral surface of the front end portion of the writing body) and the respective convex portions is further reduced, so that a smooth telescopic movement of the nib can be reliably obtained.

[0044] A thirteenth aspect of the present invention is the telescopic writing instrument of the eleventh aspect, wherein each of the convex portions has flexibility in the front-rear direction.

[0045] In the telescopic writing instrument according to the thirteenth aspect, when the nib is telescoped, each of the convex portions flexes forward and backward. That is, the top portion of each convex portion is displaced forward or backward with respect to the base portion of each convex portion. As a result, the sliding resistance between the outer peripheral surface of the writing body (for example, the outer peripheral surface of the front end portion of the writing body) and the respective convex portions is further reduced, so that a smooth telescopic movement of the nib can be reliably obtained.

[0046] A fourteenth aspect of the present invention is the telescopic writing instrument of any one of the eleventh to thirteenth aspects, wherein the annular support portion is provided on the inner surface of the front end hole, and each of the convex portions is integrally formed on the inner peripheral surface of the annular support portion.

[0047] In the telescopic writing instrument according to the fourteenth aspect, each of the convex portions can be easily provided on the inner peripheral surface of the front end hole. For the telescopic writing instrument according to the fourteenth aspect, for example, there can be cited a configuration in which the annular support portion is provided on the inner peripheral surface of the front end hole of the front end portion of the pen barrel by fixing a separate member (for example, an annular elastic body having the annular support portion), or a configuration in which the annular support portion is integrally formed on the inner peripheral surface of the front end hole of the pen barrel (that is, a configuration in which the annular support portion and the inner peripheral surface of the front end hole of the pen barrel are integrally formed of the same material).

[0048] A fifteenth aspect of the present invention is a telescopic writing instrument, characterized by comprising:

[0049] a pen barrel; and a writing body accommodated in the pen barrel so as to be movable in the front-rear direction,

[0050] a nib is provided at the front end portion of the writing body,

[0051] the nib is configured to be telescoped from the front end hole of the pen barrel,

[0052] a plurality of convex portions are provided on the inner peripheral surface of the front end hole in the circumferential direction,

[0053] each of the convex portions projects radially inward from the inner peripheral surface of the front end hole,

[0054] each of the convex portions is elastically deformable,

[0055] In a state where the nib projects outward from the front end hole, the tops of the respective convex portions are in contact with the outer peripheral surface of the front end portion of the writing body, and the inner peripheral surface of the front end hole between the adjacent convex portions is not in contact with the outer peripheral surface of the front end portion of the writing body.

[0056] For the telescopic writing instrument according to the fifteenth aspect, even when there is a dimensional deviation in both or either one of the outer diameter of the front end portion of the writing body and the inner diameter of the inner peripheral surface of the front end hole for the outer peripheral surface of the front end portion of the writing body to slide (i.e., the diameter of the virtual inscribed circle tangent to the tops of the respective convex portions), the following effects can be obtained. That is, the sliding resistance between the outer peripheral surface of the front end portion of the writing body and the respective convex portions is reduced, so that a smooth telescopic movement of the nib can be obtained. Also, the outer peripheral surface of the front end portion of the writing body is stably supported by the tops of the respective convex portions in the state where the nib projects, so that a sufficient anti-vibration effect of the nib during writing can be obtained.

[0057] In particular, for the telescopic writing instrument according to the fifteenth aspect, the respective convex portions project radially inward from the inner peripheral surface of the front end hole, whereby the tops of the respective convex portions in the state where the nib projects can stably support the outer peripheral surface of the front end portion of the writing body for a long time.

[0058] It should be noted that in the fifteenth aspect of the present invention, the outer peripheral surface of the front end portion of the writing body refers to, for example, the outer peripheral surface of a nib such as a ballpoint pen nib, the outer peripheral surface of a nib holder that holds the nib, or the outer peripheral surface of the front end portion of an ink cartridge having a nib.

[0059] Advantages of the Invention

[0060] For the telescopic writing instrument according to the present invention, both a smooth telescopic movement of the nib and a sufficient anti-vibration effect of the writing body during writing can be obtained.

[0061] The following shows an example of the above effects. That is, for example, for the telescopic writing instrument according to the present invention, both a smooth telescopic movement of the nib and a sufficient anti-vibration effect of the nib during writing can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 is a main part longitudinal sectional view showing the state where the nib is retracted in the first embodiment of the telescopic writing instrument of the present invention.

[0063] Figure 2 is showing Figure 1 the main part longitudinal sectional view of the telescopic writing instrument in the state where the nib projects.

[0064] Figure 3 is an enlarged longitudinal sectional view showing the main part of Figure 2 the same.

[0065] Figure 4 is Figure 3 a sectional view taken along line A-A (cross-sectional view) of

[0066] Figure 5 The (a) of Figure 1 is a longitudinal sectional view of the main part of the front end of the pen barrel of Figure 5 The (b) of Figure 5 is a sectional view taken along line B-B (cross-sectional view) of (a) of

[0067] Figure 6 is a longitudinal sectional view of the main part showing the state where the nib is retracted in the second embodiment of the retractable writing instrument of the present invention.

[0068] Figure 7 is showing Figure 6 a longitudinal sectional view of the main part showing the state where the nib of the retractable writing instrument of

[0069] Figure 8 The (a) of Figure 7 is a longitudinal sectional view of the main part magnified

[0070] Figure 9 is Figure 8 a sectional view taken along line C-C (cross-sectional view) of

[0071] Figure 10 The (a) of Figure 6 is a longitudinal sectional view of the main part of the front end of the pen barrel magnified Figure 10 The (b) of Figure 10 is a sectional view taken along line D-D (cross-sectional view) of (a) of

[0072] Figure 11 is a longitudinal sectional view showing the state where the nib is retracted in the third embodiment of the retractable writing instrument of the present invention.

[0073] Figure 12 is Figure 11 an enlarged view of part A2 of the retractable writing instrument of

[0074] Figure 13 The (a) of Figure 12 is a sectional view (cross-sectional view) of the section taken along line B2-B2 magnified

[0075] Figure 14 shows Figure 11 the annular support member (mode 1) of Figure 14 The (a) of Figure 14 is a perspective view, Figure 14 The (b) of

[0076] Figure 15 is showingFigure 11 An enlarged longitudinal sectional view of part A2 in the tip protruding state of a retractable writing instrument.

[0077] Figure 16 Is an enlarged view showing Figure 15 A sectional view (cross-sectional view) of the D2 - D2 line profile of

[0078] Figure 17 Is a longitudinal sectional view showing the tip retracted state of the fourth embodiment of the retractable writing instrument of the present invention.

[0079] Figure 18 Is Figure 17 An enlarged view of part E of a retractable writing instrument.

[0080] Figure 19 Is an enlarged view showing Figure 18 A sectional view (cross-sectional view) of the F - F line profile of

[0081] Figure 20 Shows another way (way 2) of the annular support member for the retractable writing instrument of the present invention. Figure 20 The (a) of is a perspective view, Figure 20 The (b) of is a front view, Figure 20 The (c) of is a right view.

[0082] Figure 21 Shows another way (way 3) of the annular support member for the retractable writing instrument of the present invention. Figure 21 The (a) of is a perspective view, Figure 21 The (b) of is a front view, Figure 21 The (c) of is a right view.

[0083] Figure 22 Shows another way (way 4) of the annular support member for the retractable writing instrument of the present invention. Figure 22 The (a) of is a perspective view, Figure 22 The (b) of is a front view, Figure 22 The (c) of is a right view.

[0084] Figure 23 Shows another way (way 5) of the annular support member for the retractable writing instrument of the present invention. Figure 23 The (a) of is a perspective view, Figure 23 The (b) of is a front view, Figure 23 The (c) of is a right view.

[0085] Figure 24 The (a) of is an enlarged longitudinal sectional view of the main part of the front end of the pen barrel of the fifth embodiment of the retractable writing instrument of the present invention, Figure 24 The (b) of is Figure 24Cross-sectional view (horizontal cross-sectional view) of the G-G line in (a). Detailed implementation mode

[0086] <First implementation mode>

[0087] Figures 1 to 5 The telescopic writing instrument 1 (1A) of the first implementation mode of the present invention is shown. The telescopic writing instrument 1 has a substantially cylindrical shape centered on the central axis O. The telescopic writing instrument 1 of the present implementation mode includes a pen barrel 2, an annular elastic body 70 (annular support portion 71), a spring 80, and a writing body 3. The pen barrel 2, the annular elastic body 70 (annular support portion 71), the spring 80, and the writing body 3 are coaxially arranged with the central axis O as a common axis. In addition, the writing body 3 has a nib 40, a nib holding cylinder 50, and an ink containing cylinder 60. The nib 40, the nib holding cylinder 50, and the ink containing cylinder 60 are arranged in a manner of being sequentially arranged along the direction extending along the central axis O.

[0088] The definition of the directions used in the present implementation mode and the like will be described.

[0089] In the present implementation mode, the direction in which the central axis O of the telescopic writing instrument 1 extends, that is, the direction along the central axis O, is referred to as the front-rear direction. It should be noted that the front-rear direction can also be referred to as the axial direction or the long dimension direction. In the front-rear direction (axial direction, long dimension direction), the nib 40 and the ink containing cylinder 60 are arranged at different positions. The direction from the ink containing cylinder 60 toward the nib 40 in the front-rear direction is referred to as the front side, and the direction from the nib 40 toward the ink containing cylinder 60 in the front-rear direction is referred to as the rear side. It should be noted that the front side can also be referred to as one side of the axial direction or one side of the long dimension direction. The rear side can also be referred to as the other side of the axial direction or the other side of the long dimension direction. In addition, the central axis O is sometimes referred to as the axis, etc.

[0090] In addition, in the present implementation mode, the state of observing a part (constituent element) or all of the telescopic writing instrument 1 from the front-rear direction is sometimes referred to as the front view observation or the front view, etc.

[0091] In addition, the direction orthogonal to the central axis O is referred to as the radial direction. The direction close to the central axis O in the radial direction is referred to as the radially inner side or simply the inner side, and the direction away from the central axis O in the radial direction is referred to as the radially outer side or simply the outer side.

[0092] In addition, the direction of surrounding the central axis O is referred to as the circumferential direction. It should be noted that sometimes the specified rotation direction centered on the central axis O in the circumferential direction is referred to as one side of the circumferential direction, and the rotation direction opposite to the specified rotation direction in the circumferential direction is referred to as the other side of the circumferential direction.

[0093] In addition, in the present embodiment, the term "telescoping" means that the writing body 3 moves in the front-rear direction relative to the pen barrel 2 between the "tip retracted state" and the "tip protruding state" described below. In addition, the inner diameter, outer diameter, and diameter respectively refer to the inner diameter dimension, outer diameter dimension, and diameter dimension.

[0094] Next, each component of the telescopic writing instrument 1 will be described in detail.

[0095] · Pen barrel

[0096] The pen barrel 2 is a cylindrical body formed of synthetic resin (e.g., polycarbonate). The writing body 3 is accommodated inside the pen barrel 2 so as to be movable back and forth (in the front-rear direction). A tapered outer surface is formed at the front end portion of the pen barrel 2, and a front end hole 21 penetrating in the axial direction is formed at its front end. The front end hole 21 is a substantially circular hole extending in the front-rear direction with the central axis O as the center. The tip 40 (ballpoint pen tip) of the writing body 3 is configured to be able to telescope from the front end hole 21 of the pen barrel 2.

[0097] · Annular elastic body

[0098] An annular elastic body 70 is fitted on the inner peripheral surface of the front end hole 21. Specifically, an annular groove 22 is formed on the inner peripheral surface of the front end hole 21, and the annular elastic body 70 is fitted in the annular groove 22. The annular groove 22 is a groove recessed radially outward from the inner peripheral surface of the front end hole 21 and is annular with the central axis O as the center. The annular groove 22 has: a front surface 22a, disposed at the front end portion in the annular groove 22 and facing the rear side; a rear surface 22b, disposed at the rear end portion in the annular groove 22 and facing the front side; and a bottom surface 22c, connecting the respective radially outer ends of the front surface 22a and the rear surface 22b and extending in the circumferential direction (see Figure 3 ). In the present embodiment, the annular groove 22 is formed in the front end hole 21, but as long as the annular groove 22 is formed on the inner peripheral surface of the pen barrel 2, it may be formed at any position. When the annular groove 22 is formed in the front end hole 21, the annular elastic body 70 disposed in the annular groove 22 can hold the writing body 3 at a position close to the tip 40 in the tip protruding state, which is preferable.

[0099] The annular elastic body 70 includes: an annular support portion 71; a plurality of (for example, four) convex portions 72 integrally formed on the inner peripheral surface of the annular support portion 71; and a plurality of (for example, four) concave portions 73 provided between adjacent convex portions 72 on the inner peripheral surface of the annular support portion 71. It should be noted that "adjacent" in this embodiment means, for example, being arranged adjacent in the circumferential direction or the like. The annular support portion 71 is in a circular ring shape centered on the central axis O. The annular support portion 71 has a plurality of convex portions 72 arranged at intervals in the circumferential direction. In a state where the annular support portion 71 (annular elastic body 70) is assembled in the annular groove 22, each convex portion 72 protrudes radially inward from the inner peripheral surface of the front end hole 21. The plurality of convex portions 72 are provided on the inner peripheral surface of the front end hole 21 in a circumferentially arranged manner. Each convex portion 72 is arranged at equal intervals in the circumferential direction. Each concave portion 73 penetrates in the front-rear direction and opens radially inward. Each convex portion 72 is integrally formed of the same material as the annular support portion 71. Each convex portion 72 can be elastically deformed in the radial direction.

[0100] Each convex portion 72 protrudes radially inward (that is, a direction perpendicular to the axis of the pen barrel 2 and toward the axis). All of the convex portions 72 are located inside the annular support portion 71 and do not protrude forward or backward from the annular support portion 71. Thus, the top of each convex portion 72 in the state where the pen tip protrudes can stably support the outer peripheral surface of the front end portion of the writing body 3 for a long time. That is, the annular support portion 71 having a plurality of convex portions 72 is provided on the inner peripheral surface of the pen barrel 2, and the annular support portion 71 supports the outer peripheral surface of the writing body 3 via each convex portion 72.

[0101] As Figure 5 shown in (a) of, the outer surface of the portion of the annular elastic body 70 having each convex portion 72 (that is, the outer surfaces of the annular support portion 71 and each convex portion 72) is formed in a longitudinal section circular shape.

[0102] As Figure 5 shown in (a) of, the top (radially inner end) of each convex portion 72 is formed in a longitudinal section arc shape (longitudinal section convex curved surface shape). That is, the top of each convex portion 72 is in an arc shape protruding toward the radial inner side under the longitudinal section view shown in Figure 5 (a) of. In addition, as Figure 5 shown in (b) of, the top (radially inner end) of each convex portion 72 is formed in a cross section arc shape (cross section concave curved surface shape). That is, the top of each convex portion 72 is in an arc shape recessed toward the radial outer side (which can also be said to be an arc shape extending in the circumferential direction) under the cross section view shown in Figure 5 (b) of. Thus, in the state where the pen tip protrudes, the top of each convex portion 72 contacts the outer peripheral surface of the front end portion (pen tip 40) of the writing body 3 in a point shape or a circumferential line shape (a line shape extending in the circumferential direction).

[0103] In addition, in other words, each convex portion 72 and each concave portion 73 can also be configured as follows: A plurality of axially penetrating concave portions 73 are circumferentially arranged at equal intervals on the inner peripheral surface of an annular portion (a general existing O-ring) having a circular cross-sectional shape, and a plurality of convex portions 72 are formed on the inner peripheral surface of the annular portion except for the adjacent concave portions 73.

[0104] In the present embodiment, the surface of each concave portion 73 facing radially inward is [[ID=?]]Figure 5 in the longitudinal sectional view shown in (a) of [[ID=?]]Figure 5 and extends linearly in the front-rear direction. In addition, the surface of each concave portion 73 facing radially inward is

[0105] In addition, as Figure 4 and [[ID=7?]]Figure 5 show, each convex portion 72 respectively has a support portion 5 disposed at the top and an elastic deformation portion 6 disposed radially outside the support portion 5. That is, the annular support portion 71 has a support portion 5 that supports the outer peripheral surface of the writing body 3, and the support portion 5 can move in the diameter-expanding direction by contact with the outer peripheral surface of the writing body 3. In addition, the annular support portion 71 partially has an elastic deformation portion 6, and the elastic deformation portion 6 can preferentially elastically deform compared to other portions of the annular support portion 71 when the outer peripheral surface of the writing body 3 contacts the support portion 5.

[0106] The annular elastic body 70 (annular support portion 71) is clamped from the front and rear directions by the front surface 22a and the rear surface 22b, and is thus held in the annular groove 22. In addition, the annular elastic body 70 is surrounded from the radially outer side by the bottom surface 22c over the entire circumference in the circumferential direction.

[0107] The annular elastic body 70 is formed of a material having rubber elasticity. That is, the annular support portion 71 and each convex portion 72 are integrally formed of the same material having rubber elasticity. Examples of the material having rubber elasticity include synthetic resins having rubber elasticity (rubbers, elastomers), and specifically, silicone rubber, nitrile rubber, ethylene-propylene-diene rubber, butyl rubber, chloroprene rubber, acrylonitrile-butadiene rubber, polyurethane rubber, fluororubber, polysulfide rubber, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, etc.

[0108] As Figures 1 to 3 shows, a spring 80 (compression coil spring) is accommodated inside the front end portion of the pen barrel 2. The front end of the spring 80 is fixed to the inner wall behind the front end hole 21 of the pen barrel 2. The writing body 3 is urged rearward by the spring 80. A telescopic mechanism (not shown) is provided inside the pen barrel 2, and the telescopic mechanism moves the writing body 3 forward against the rearward urging force of the spring 80.

[0109] As the telescopic mechanism, for example, a rear-press type, a side-sliding type, a rotary type, etc. can be cited. The rear-press type is a method of making the nib 40 extend and retract from the front end hole 21 by pressing the operation part provided at the rear end of the pen barrel 2 forward. The side-sliding type is a method of making the nib 40 extend and retract from the front end hole 21 by sliding the operation part (such as a pen clip) provided on the side surface of the pen barrel 2 forward. In addition, the rotary type is a method of making the nib 40 extend and retract from the front end hole 21 by rotating the operation part provided on the outer surface of the pen barrel 2.

[0110] · Writing style

[0111] The writing body 3 includes: a nib 40 (a ballpoint pen nib), disposed at the front end of the writing body 3; a nib holding cylinder 50 for fitting the nib 40; and an ink containing cylinder 60 for fitting the nib holding cylinder 50.

[0112] · Nib

[0113] The nib 40 is composed of a ballpoint pen nib. The ballpoint pen nib is composed of a main body and a ball 40a. The main body is composed of a cylindrical body made of metal (such as stainless steel), and the ball 40a is rotatably held at the front end of the main body. The main body includes: a tapered front part 41 that holds the ball 40a at its front end; a straight cylindrical middle part 42 integrally connected to the rear of the front part 41; and a rear part 43 integrally connected to the rear of the middle part 42. The rear part 43 has an outer diameter smaller than that of the middle part 42. The rear part 43 is press-fitted and fixed into the fitting hole 54 of the nib holding cylinder 50. In a state where the ballpoint pen nib is fitted into the nib holding cylinder 50, the front end of the nib holding cylinder 50 abuts against the step part 44 between the middle part 42 and the rear part 43. It should be noted that an elastic body (such as a spring) that applies a forward force to the ball 40a can also be accommodated in the main body of the ballpoint pen nib.

[0114] The outer diameter of the middle part 42 of the ballpoint pen nib is set to be slightly larger than the inner diameter of the top of each convex part 72 of the annular elastic body 70 fitted on the inner peripheral surface of the front end hole 21 (that is, the diameter of the virtual inscribed circle tangent to the top of each convex part 72). In other words, the outer diameter of the nib 40 is larger than the diameter of the virtual inscribed circle passing through the support part 5 disposed at the top of each of the plurality of convex parts 72. Thus, the outer surface of the middle part 42 and the top of each convex part 72 can slide in the front-rear direction in a press-contact state.

[0115] · Nib holding cylinder

[0116] As Figure 1 and Figure 2As shown, the nib holding cylinder 50 includes: a front cylinder portion 51; an annular flange portion 53 integrally connected to the rear of the front cylinder portion 51; and a rear cylinder portion 52 integrally connected to the rear of the flange portion 53. The nib holding cylinder 50 is formed from a molded body of synthetic resin (such as polypropylene).

[0117] The front cylinder portion 51 is composed of a tapered cylindrical portion. An assembly hole 54 opening forward is formed at the front end of the front cylinder portion 51. The rear portion 43 of the ballpoint pen nib is press-fitted and fixed in the assembly hole 54. A forward step portion is formed on the outer surface of the front cylinder portion 51, and the rear end of the spring 80 is fixed to the forward step portion. The flange portion 53 abuts against the front end of the ink containing cylinder 60. The rear cylinder portion 52 is press-fitted and fixed to the front end opening portion of the ink containing cylinder 60.

[0118] · Ink containing cylinder

[0119] The ink containing cylinder 60 is a cylindrical body obtained by extrusion molding of synthetic resin (such as polypropylene). Ink is contained in the ink containing cylinder 60. The ink in the ink containing cylinder 60 passes through the inside of the nib holding cylinder 50 and is supplied into the ballpoint pen nib, and is discharged to the outside as the ball 40a at the front end of the ballpoint pen nib rotates. It should be noted that, in addition, for example, there may be a configuration in which the nib holding cylinder 50 and the ink containing cylinder 60 are integrally formed and the ink containing cylinder 60 also serves as the nib holding cylinder 50, or a configuration in which the ink containing cylinder 60 is directly fixed to the nib 40, etc.

[0120] · Nib retracted state ( Figure 1 )

[0121] As Figure 1 shown, in the state where the nib 40 (ballpoint pen nib) is retracted into the pen barrel 2 (when not writing), the outer peripheral surface of the ballpoint pen nib and the convex portions 72 on the inner peripheral surface of the front end hole 21 of the pen barrel 2 are in a non-contact state. In the nib retracted state shown in Figure 1 , the nib 40 is disposed at a position rearward of the annular elastic body 70 (annular support portion 71).

[0122] · Nib protruding state ( Figure 2 )

[0123] From Figure 1 the state where the nib 40 (ballpoint pen nib) is retracted into the pen barrel 2, the telescopic mechanism is operated, so that the writing body 3 moves forward against the rearward force of the spring 80. As a result, as Figure 2 shown, it becomes a state where the ballpoint pen nib protrudes more outward than the front end hole 21 (writable state). In changing from the nib retracted state shown in Figure 1 to Figure 2During the process of the tip projecting state shown, the top of each convex portion 72 and the outer peripheral surface of the front end portion of the writing body 3 (the outer peripheral surface of the tip 40) slide in the front-rear direction.

[0124] In the tip projecting state, the outer peripheral surface of the middle portion 42 of the ballpoint pen tip is in contact with (or crimped to) the top of each convex portion 72, and each convex portion 72 elastically deforms (compresses) radially outward. Thereby, the wobbling of the tip 40 during writing can be reliably prevented.

[0125] In addition, in this state, there is a radial gap between the concave portion 73 between adjacent convex portions 72 and the outer peripheral surface of the middle portion 42 of the ballpoint pen tip. That is, the inner peripheral surface of the front end hole 21 between adjacent convex portions 72 is not in contact with the outer peripheral surface of the ballpoint pen tip. Thereby, the smooth sliding of the outer peripheral surface of the ballpoint pen tip and the inner peripheral surface of the front end hole 21 can be maintained, and thus a smooth telescopic movement of the ballpoint pen tip can be obtained.

[0126] The telescopic writing instrument 1 of the present embodiment is a telescopic writing instrument characterized by including: a pen barrel 2; and a writing body 3 accommodated in the pen barrel 2 so as to be movable in the front-rear direction, a tip 40 is provided at the front end portion of the writing body 3, the tip 40 is configured to be able to telescopically move out of the front end hole 21 of the pen barrel 2, a plurality of convex portions 72 are provided along the circumferential direction on the inner peripheral surface of the front end hole 21, each convex portion 72 projects radially inward from the inner peripheral surface of the front end hole 21, each convex portion 72 can elastically deform, and in a state where the tip 40 projects out of the front end hole 21 to the outside, the top of each convex portion 72 is in contact with the outer peripheral surface of the front end portion (tip 40) of the writing body 3, and the inner peripheral surface of the front end hole 21 between adjacent convex portions 72 is not in contact with the outer peripheral surface of the front end portion (tip 40) of the writing body 3.

[0127] Thereby, even when there is a dimensional deviation in both or either one of the outer diameter of the front end portion of the writing body 3 and the inner diameter of the inner peripheral surface of the front end hole 21 for the outer peripheral surface of the front end portion (tip 40) of the writing body 3 to slide (that is, the diameter of the virtual inscribed circle tangent to the top of each convex portion 72), the telescopic writing instrument 1 of the present embodiment can obtain the following effects. That is, the sliding resistance between the outer peripheral surface of the front end portion of the writing body 3 and each convex portion 72 is reduced, and thus a smooth telescopic movement of the tip 40 can be obtained. And the outer peripheral surface of the front end portion of the writing body 3 is stably supported by the top of each convex portion 72 in the tip projecting state, and thus a sufficient anti-vibration effect of the tip 40 during writing can be obtained.

[0128] The telescopic writing instrument 1 of the present embodiment is a telescopic writing instrument in which the top of each convex portion 72 is a convex curved surface in longitudinal section. Thus, in the telescopic writing instrument 1 of the present embodiment, the outer peripheral surface of the front end portion (the nib 40) of the writing body 3 contacts the top of each convex portion 72 in a point-like or circumferential linear manner. The contact resistance between the outer peripheral surface of the front end portion of the writing body 3 and each convex portion 72 is further reduced, so that a smooth telescopic movement of the nib 40 can be reliably obtained.

[0129] The telescopic writing instrument 1 of the present embodiment is a telescopic writing instrument in which an annular support portion 71 is provided on the inner surface of the front end hole 21 and each convex portion 72 is integrally formed on the inner peripheral surface of the annular support portion 71. Thus, in the telescopic writing instrument 1 of the present embodiment, each convex portion 72 can be easily provided on the inner peripheral surface of the front end hole 21.

[0130] <Second Embodiment>

[0131] Figures 6 to 10 The telescopic writing instrument 1 (1B) of the second embodiment of the present invention is shown. It should be noted that in the present embodiment, the same components as those in the foregoing embodiment may be denoted by the same names, reference numerals, etc., and the description thereof may be omitted. In addition, unless otherwise specified, the definition of directions and the like are also the same as those in the foregoing embodiment.

[0132] ·Barrel

[0133] The barrel 2 is a cylindrical body formed of a synthetic resin (e.g., polypropylene). The writing body 3 is accommodated in the barrel 2 so as to be movable back and forth. A tapered outer surface is formed at the front end portion of the barrel 2, and a front end hole 21 penetrating in the axial direction is formed at its front end. The nib 40 (ballpoint pen nib) of the writing body 3 is configured to be telescopic from the front end hole 21 of the barrel 2.

[0134] ·Annular support portion and convex portion

[0135] An annular support portion 21a is integrally formed on the inner peripheral surface of the front end hole 21 from the same material (e.g., polypropylene) as the front end portion of the barrel 2. A plurality of (e.g., four) convex portions 21b are integrally formed on the inner peripheral surface of the annular support portion 21a from the same material (e.g., polypropylene) as the front end portion of the barrel 2 (the annular support portion 21a). That is, in the foregoing embodiment, the annular support portion 71 (the annular elastic body 70) is separately formed from the inner peripheral surface of the barrel 2 and assembled in the annular groove 22, while in the present embodiment, the annular support portion 21a is integrally formed on the inner peripheral surface of the barrel 2. These annular support portions 71, 21a may also be respectively renamed as annular support structures or the like. As Figure 10As shown in (a) of [reference], each convex portion 21b is formed into a thin plate shape extending radially inward, having flexibility in the front-rear direction. Each convex portion 21b contacts the outer peripheral surface of the front end portion of the writing body 3 by the telescopic movement of the nib, and thus flexes in the front-rear direction. A plurality (for example, four) of concave portions 21c are formed between adjacent convex portions 21b on the inner peripheral surface of the annular support portion 21a. Each convex portion 21b protrudes radially inward. The convex portions 21b are arranged at equal intervals in the circumferential direction. Each concave portion 21c penetrates in the front-rear direction and opens radially inward.

[0136] Each convex portion 21b protrudes radially inward (that is, a direction perpendicular to the axis of the pen barrel 2 and facing the axis). Thus, the top of each convex portion 21b in the state where the nib protrudes can stably support the outer peripheral surface (the outer peripheral surface of the nib 40) of the front end portion of the writing body 3 for a long time.

[0137] As shown in Figure 10 (b) of [reference], the top (the radially inner end portion) of each convex portion 21b is formed into an arc shape in cross section (a concave curved surface shape in cross section). That is, the top of each convex portion 21b is in an arc shape that is recessed toward the radially outer side when observed in the cross-sectional view shown in Figure 10 (b) of [reference] (which can also be said to be an arc shape extending in the circumferential direction). Thus, in the state where the nib protrudes, the top of each convex portion 21b contacts the outer peripheral surface of the front end portion (the nib 40) of the writing body 3 in a point-like or circumferentially linear manner.

[0138] More specifically, the convex portion 21b has a pair of plate surfaces facing the front-rear direction, an inner peripheral surface facing radially inward, and a chamfered portion 21d. Among the pair of plate surfaces of the convex portion 21b, one plate surface facing the front side is the front surface, and the other plate surface facing the rear side is the rear surface. The front surface and the rear surface are each in a planar shape extending in a direction perpendicular to the central axis O (the surface direction), and specifically, they are in an arc shape extending in the circumferential direction.

[0139] In addition, the inner peripheral surface of the convex portion 21b is in a linear shape extending in the front-rear direction when observed in the longitudinal sectional view shown in Figure 10 (a) of [reference]. In addition, the inner peripheral surface of the convex portion 21b is in an arc shape extending in the circumferential direction when observed in the cross-sectional view shown in Figure 10 (b) of [reference]. That is, the inner peripheral surface of the convex portion 21b is in a cylindrical surface shape (the shape of the inner peripheral surface of a cylinder).

[0140] In addition, the chamfered portion 21d is arranged at the connecting portion between the rear surface and the inner peripheral surface of the convex portion 21b. The chamfered portion 21d extends forward as it tends radially inward from the connecting portion with the rear surface toward the connecting portion with the inner peripheral surface. By providing the chamfered portion 21d, the sliding between the outer peripheral surface of the nib 40 and each convex portion 21b becomes smoother.

[0141] In addition, as shown in Figure 9 andFigure 10 As shown, each convex portion 21b has a support portion 5 disposed at the top and an elastic deformation portion 6 disposed radially outward of the support portion 5. That is, the annular support portion 21a has a support portion 5 that supports the outer peripheral surface of the writing body 3, and the support portion 5 can move in the front-rear direction by contact with the outer peripheral surface of the writing body 3. In addition, the annular support portion 21a partially has an elastic deformation portion 6, and the elastic deformation portion 6 can elastically deform prior to other portions of the annular support portion 21a when the outer peripheral surface of the writing body 3 contacts the support portion 5.

[0142] As Figures 6 to 8 shown, a spring 80 (compression coil spring) is accommodated inside the front end portion of the pen barrel 2. The front end of the spring 80 is fixed to the inner wall behind the front end hole 21 of the pen barrel 2. The writing body 3 is urged rearward by the spring 80. A telescopic mechanism (not shown) is provided inside the pen barrel 2, and the telescopic mechanism moves the writing body 3 forward against the rearward urging force of the spring 80.

[0143] As the telescopic mechanism, for example, a rear-end push type, a side-sliding type, a rotary type, etc. can be cited. The rear-end push type is a method of making the nib 40 extend and retract from the front end hole 21 by pressing an operation portion provided at the rear end of the pen barrel 2 forward. The side-sliding type is a method of making the nib 40 extend and retract from the front end hole 21 by sliding an operation portion (such as a pen clip) provided on the side surface of the pen barrel 2 forward. In addition, the rotary type is a method of making the nib 40 extend and retract from the front end hole 21 by rotating an operation portion provided on the outer surface of the pen barrel 2.

[0144] · Writing body

[0145] The writing body 3 includes: a nib 40 (ballpoint pen nib), disposed at the front end portion of the writing body 3; a nib holding cylinder 50 for assembling the nib 40; and an ink containing cylinder 60 for assembling the nib holding cylinder 50.

[0146] · Nib

[0147] The nib 40 is composed of a ballpoint pen nib. The ballpoint pen nib is composed of a main body and a ball 40a. The main body is composed of a cylindrical body made of metal (such as stainless steel), and the ball 40a is rotatably held at the front end of the main body. The main body includes: a tapered front portion 41 that holds the ball 40a at its front end; a straight cylindrical intermediate portion 42 that is integrally connected to the rear of the front portion 41; and a rear portion 43 that is integrally connected to the rear of the intermediate portion 42. The rear portion 43 has an outer diameter smaller than that of the intermediate portion 42. The rear portion 43 is press-fitted and fixed to the fitting hole 54 of the nib holding cylinder 50. In a state where the ballpoint pen nib is assembled to the nib holding cylinder 50, the front end of the nib holding cylinder 50 abuts against a step portion 44 between the intermediate portion 42 and the rear portion 43. It should be noted that an elastic body (such as a spring) that urges the ball 40a forward can also be accommodated inside the main body of the ballpoint pen nib.

[0148] The outer diameter of the middle portion 42 of the ballpoint pen tip is set to be slightly larger than the inner diameter of the top of each convex portion 21b formed integrally on the inner peripheral surface of the front end hole 21 (i.e., the diameter of the virtual inscribed circle tangent to the top of each convex portion 21b). In other words, the outer diameter of the pen tip 40 is larger than the diameter of the virtual inscribed circle passing through the support portions 5 disposed at the tops of the plurality of convex portions 21b. Thus, the outer surface of the middle portion 42 and the tops of the respective convex portions 21b can slide in the front-rear direction in a crimped state.

[0149] ·Pen tip holding cylinder

[0150] As Figure 6 and Figure 7 shown, the pen tip holding cylinder 50 includes: a front cylinder portion 51; an annular flange portion 53 integrally connected to the rear of the front cylinder portion 51; and a rear cylinder portion 52 integrally connected to the rear of the flange portion 53. The pen tip holding cylinder 50 is obtained from a molded body of synthetic resin (such as polypropylene).

[0151] The front cylinder portion 51 is composed of a tapered cylindrical portion. An assembly hole 54 opening forward is formed at the front end of the front cylinder portion 51. The rear portion 43 of the ballpoint pen tip is press-fitted and fixed in the assembly hole 54. A forward step portion is formed on the outer surface of the front cylinder portion 51, and the rear end of the spring 80 is engaged with the forward step portion. The flange portion 53 abuts against the front end of the ink storage cylinder 60. The rear cylinder portion 52 is press-fitted and fixed in the front end opening portion of the ink storage cylinder 60.

[0152] ·Ink storage cylinder

[0153] The ink storage cylinder 60 is a cylindrical body obtained by extrusion molding of synthetic resin (such as polypropylene). Ink is stored in the ink storage cylinder 60. The ink in the ink storage cylinder 60 is supplied into the ballpoint pen tip through the pen tip holding cylinder 50 and discharged to the outside as the ball 40a at the front end of the ballpoint pen tip rotates. It should be noted that, in addition to this, for example, there can be cited a configuration in which the pen tip holding cylinder 50 and the ink storage cylinder 60 are integrally formed and the ink storage cylinder 60 also serves as the pen tip holding cylinder 50, or a configuration in which the ink storage cylinder 60 is directly fixed to the pen tip 40, etc.

[0154] ·State where the pen tip is retracted ( Figure 6 )

[0155] As Figure 6 shown, in the state where the pen tip 40 (ballpoint pen tip) is retracted into the pen barrel 2 (when not writing), the outer peripheral surface of the ballpoint pen tip is in a non-contact state with the inner peripheral surface of each convex portion 21b of the front end hole 21 of the pen barrel 2. In the Figure 6 shown state where the pen tip is retracted, the pen tip 40 is disposed at a position rearward of the annular support portion 21a.

[0156] · Tip protruding state ( Figure 7 )

[0157] From the state where the tip 40 (ballpoint pen tip) of Figure 6 is retracted into the pen barrel 2, operate the telescopic mechanism to move the writing body 3 forward against the rearward force of the spring 80. As a result, as Figure 7 shown, it becomes a state where the ballpoint pen tip protrudes more externally than the front end hole 21 (writable state). When changing from the Figure 6 tip retracted state shown to the Figure 7 tip protruding state shown, the top of each convex portion 21b and the outer peripheral surface of the front end portion of the writing body 3 (outer peripheral surface of the tip 40) slide in the front-rear direction.

[0158] In the tip protruding state, the outer peripheral surface of the middle portion 42 of the ballpoint pen tip is in contact with (or crimped state) the top of each convex portion 21b and each convex portion 21b is flexed forward. That is, the top of each convex portion 21b is displaced forward relative to the base of each convex portion 21b. Thus, the shaking of the tip 40 during writing can be reliably prevented.

[0159] In addition, in this state, there is a radial gap between the concave portion 21c between adjacent convex portions 21b and the outer peripheral surface of the middle portion 42 of the ballpoint pen tip. That is, the inner peripheral surface of the front end hole 21 between adjacent convex portions 21b is not in contact with the outer peripheral surface of the ballpoint pen tip. Thus, the smooth sliding between the outer peripheral surface of the ballpoint pen tip and the inner peripheral surface of the front end hole 21 can be maintained, and a smooth telescopic movement of the ballpoint pen tip can be obtained.

[0160] Moreover, when changing from this tip protruding state to the tip retracted state, each convex portion 21b returns to the state of protruding in a direction perpendicular to the axis ( Figure 6 state) or a state of being slightly flexed forward or backward. That is, the top of each convex portion 21b returns to the same position in the front-rear direction relative to the base of each convex portion 21b or a state of being slightly displaced forward or backward.

[0161] The telescopic writing instrument 1 of the present embodiment is a telescopic writing instrument characterized by including: a pen barrel 2; and a writing body 3 accommodated in the pen barrel 2 so as to be movable in the front-rear direction. A nib 40 is provided at the front end of the writing body 3, and the nib 40 is configured to be telescopic from the front end hole 21 of the pen barrel 2. A plurality of convex portions 21b are provided on the inner peripheral surface of the front end hole 21 along the circumferential direction. Each of the convex portions 21b projects radially inward from the inner peripheral surface of the front end hole 21, and each of the convex portions 21b can be elastically deformed. In a state where the nib 40 projects from the front end hole 21 to the outside, the top of each of the convex portions 21b is in contact with the outer peripheral surface of the front end of the writing body 3 (nib 40), and the inner peripheral surface of the front end hole 21 between the adjacent convex portions 21b is in a non-contact state with the outer peripheral surface of the front end of the writing body 3 (nib 40).

[0162] Accordingly, even when there is a dimensional deviation in either both or any one of the outer diameter of the front end of the writing body 3 (nib 40) and the inner diameter of the inner peripheral surface of the front end hole 21 for the outer peripheral surface of the front end of the writing body 3 (nib 40) to slide (i.e., the diameter of the virtual inscribed circle tangent to the top of each convex portion 21b), the telescopic writing instrument 1 of the present embodiment can obtain the following effects. That is, the sliding resistance between the outer peripheral surface of the front end of the writing body 3 (nib 40) and each convex portion 21b is reduced, so that a smooth telescopic action of the nib 40 can be obtained. In addition, the dimensional deviation is absorbed, and the outer peripheral surface of the front end of the writing body 3 (nib 40) is stably supported by the top of each convex portion 21b in a state where the nib projects, so that a sufficient anti-vibration effect of the nib 40 during writing can be obtained.

[0163] The telescopic writing instrument 1 of the present embodiment is a telescopic writing instrument in which each of the convex portions 21b has flexibility in the front-rear direction. Accordingly, in the telescopic writing instrument 1 of the present embodiment, each convex portion 21b flexes in the front-rear direction when the nib telescopes. That is, the top of each convex portion 21b is displaced forward or backward with respect to the base of each convex portion 21b. As a result, the sliding resistance between the outer peripheral surface of the front end of the writing body 3 (nib 40) and each convex portion 21b is further reduced, so that a smooth telescopic action of the nib 40 can be reliably obtained.

[0164] The telescopic writing instrument 1 of the present embodiment is a telescopic writing instrument in which a ring-shaped support portion 21a is provided on the inner surface of the front end hole 21 and each of the convex portions 21b is integrally formed on the inner peripheral surface of the ring-shaped support portion 21a. Accordingly, in the telescopic writing instrument 1 of the present embodiment, each convex portion 21b can be easily provided on the inner peripheral surface of the front end hole 21.

[0165] <Third Embodiment>

[0166] Figures 11 to 16 1C) of a third embodiment of the present invention is shown. It should be noted that in this embodiment, the same components as those in the previous embodiments are sometimes given the same names, reference numerals, etc., and their descriptions are omitted. Furthermore, unless otherwise specified, the definitions of directions, etc., are also the same as those in the previous embodiments.

[0167] ·pen

[0168] The pen barrel 2 is a cylindrical body formed of a synthetic resin (for example, polycarbonate). The pen barrel 2 comprises: a tapered front shaft having a front end hole 21 at the front end; an intermediate shaft that is detachably screwed to the rear end of the front shaft; and a rear shaft that is coupled to the rear end of the intermediate shaft. The writing body 3 is accommodated inside the pen barrel 2 in a manner that allows it to move forward and backward. A tapered outer surface is formed at the front end portion (front shaft) of the pen barrel 2, and a front end hole 21 that penetrates in the axial direction is formed at the front end thereof. The pen tip 31 (ballpoint pen tip) of the writing body 3 is configured to be retractable from the front end hole 21 of the pen barrel 2.

[0169] Ring-shaped support member (method 1)

[0170] An annular support member (annular support portion) 4 is mounted on the inner circumference of the front end hole 21. Specifically, an annular groove 22 is formed on the inner circumference of the front end hole 21, and the annular support member 4 is fitted into this annular groove 22. That is, in this embodiment, the annular support member (annular support portion) 4 is formed separately from the inner circumference of the pen barrel 2 and mounted in the annular groove 22. This annular support member (annular support portion) 4 may also be referred to as an annular support structure.

[0171] like Figure 14 As shown, the annular support member 4 is a structure in which a plurality of (for example, five) support portions 5, a plurality of (for example, five) base portions 7 and a plurality of (for example, ten) elastic deformation portions 6 are integrally connected. That is, in the present embodiment, the annular support member 4 includes a plurality of support portions 5, a plurality of base portions 7 and a plurality of elastic deformation portions 6. In addition, as described later, the annular support member 4 of the present embodiment also includes a plurality of outer notches 9 and a plurality of inner notches 8. The annular support member 4 is a member formed as a whole in an annular shape. The annular support member 4 is annular and extends around the central axis O. In the shape of the portion of the annular support member 4 other than the outer notch 9 and the inner notch 8, the cross section (that is, the longitudinal section) obtained by cutting between the inner side and the outer side in the axial direction and in the radial direction has a circular shape.

[0172] Supporting part

[0173] A plurality of supporting portions 5 are arranged on the inner peripheral portion of the annular supporting member 4. The plurality of supporting portions 5 are arranged in a circumferential direction. Specifically, the plurality of supporting portions 5 are arranged at intervals in the circumferential direction. Each supporting portion 5 extends in the circumferential direction. Each supporting portion 5 is arranged at equal intervals in a circumferential shape. It should be noted that the "arranged in a circumferential shape" mentioned in the present embodiment means arranged in a manner of being arranged in the circumferential direction around the central axis O. The inner side surface of each supporting portion 5 forms a concave curved surface under a front view observation, and is in line contact with the outer peripheral surface (the outer peripheral surface of the nib 31) of the writing body 3 in a line extending in the circumferential direction. The inner side surface of each supporting portion 5 is arranged on a virtual inscribed circle under a front view observation. The diameter of the virtual inscribed circle is set to be slightly smaller than the outer diameter of the outer peripheral surface (the outer peripheral surface of the nib 31) of the writing body 3. The sum of the circumferential dimensions of the inner side surfaces of the plurality of supporting portions 5 is set to be about 70% based on the length of the circumference of the virtual inscribed circle passing through the inner side surfaces of these supporting portions 5 (100%). Thus, each supporting portion 5 is liable to displace in the direction of diameter expansion (liable to elastic deformation).

[0174] As Figure 14 shown in (b) of, the inner side surface of each supporting portion 5 extends in an arc shape centered on the central axis O under a front view observation from the front-rear direction (axial direction). The inner side surface of each supporting portion 5 forms an arc shape recessed toward the radially outer side under this front view observation. In addition, the inner side surface of each supporting portion 5 forms an arc shape protruding toward the radially inner side under a longitudinal sectional view observation perpendicular to the circumferential direction (a longitudinal sectional view observation by cutting along a virtual plane including the central axis O in the plane) (refer to Figure 15 ).

[0175] ·Base

[0176] A plurality of bases 7 are arranged on the outer peripheral portion of the annular supporting member 4. The plurality of bases 7 are arranged in a circumferential direction. Specifically, the plurality of bases 7 are arranged at intervals in the circumferential direction. Each base 7 is arranged on the inner peripheral surface of the pen barrel 2. Each base 7 extends in the circumferential direction. Each base 7 is arranged at equal intervals in a circumferential shape. The outer side surface of each base 7 forms a convex curved surface under a front view observation, and is in line contact with the bottom surface 22c of the annular groove 22 of the pen barrel 2 in a line extending in the circumferential direction (refer to Figure 12 ). The outer side surface of each base 7 is arranged on a virtual circumscribed circle under a front view observation. The diameter of the virtual circumscribed circle is set to be slightly larger than the inner diameter of the bottom surface 22c of the annular groove 22 of the pen barrel 2. The base 7 is in line contact with the bottom surface 22c of the annular groove 22 and is clamped front and back by the front surface 22a and the rear surface 22b of the annular groove 22.

[0177] In the present embodiment, as Figure 12As shown, the position of the radially inner end of the rear surface 22b of the annular groove 22 is arranged at a position radially outward of the position of the radially inner end of the front surface 22a, and the amount of protrusion of the rear surface 22b toward the radially inner side is smaller than the amount of protrusion of the front surface 22a toward the radially inner side. Specifically, the rear surface 22b is arranged on the wall portion (front wall) of the annular protrusion that protrudes radially inward from the inner peripheral surface of the front end hole 21 and extends in the circumferential direction. Therefore, when assembling the telescopic writing instrument 1, the annular support member 4 can pass over the rear surface 22b from the rear side toward the front side together with the annular protrusion. It should be noted that a plurality of linearly extending protrusions extending in the circumferential direction may be provided at intervals in the circumferential direction instead of the annular protrusion. According to the present embodiment, the operation of assembling the annular support member 4 into the annular groove 22 is easy. In addition, the annular support member 4 arranged in the annular groove 22 is clamped by the front surface 22a and the rear surface 22b in the front-rear direction, so that the annular support member 4 can be restricted from moving in the front-rear direction in the annular groove 22. Therefore, the annular support member 4 is stably held in the annular groove 22.

[0178] · Elastic deformation portion

[0179] A plurality of elastic deformation portions 6 are arranged in a circumferentially arranged manner. Specifically, the plurality of elastic deformation portions 6 are arranged at intervals in the circumferential direction. Each elastic deformation portion 6 is located between the inner peripheral portion and the outer peripheral portion of the annular support member 4. The elastic deformation portion 6 connects the support portion 5 located at the inner peripheral portion of the annular support member 4 and the base portion 7 located at the outer peripheral portion. The elastic deformation portion 6 extends inward from the base portion 7 and extends outward from the support portion 5. The elastic deformation portion 6 extends toward the circumferential direction as it tends to be radial. That is, the elastic deformation portion 6 extends in an inclined orientation with respect to a specified radial direction when viewed from the front-rear direction. Each elastic deformation portion 6 protrudes from the inner surface of the base portion 7 in a direction deviated from the center direction (centripetal direction) of the annular support member 4. That is, each elastic deformation portion 6 protrudes from the inner surface of the base portion 7 in a direction not facing the center of the annular support member 4. Each elastic deformation portion 6 is formed such that the center M (central axis O) of the annular support member 4 does not exist on the extension line of the virtual straight line P connecting the center of the inner end portion of each elastic deformation portion 6 and the center of the outer end portion of each elastic deformation portion 6. Each elastic deformation portion 6 elastically deforms in a manner of tilting radially outward when the outer peripheral surface of the writing body 3 comes into contact with the support portion 5. That is, when the outer peripheral surface of the writing body 3 comes into contact with the support portion 5, each elastic deformation portion 6 tilts while further increasing the inclination angle with respect to the specified radial direction and elastically deforms. Through the elastic deformation of each of the elastic deformation portions 6, the radial distance between the support portion 5 and the base portion 7 becomes smaller.

[0180] Each elastic deformation portion 6 has a curved shape that is convex on the outside and concave on the inside. Specifically, Figure 14When observed from the front as shown in FIG. (b), the outer side surface of each elastic deformation portion 6 facing radially outward is in a curved shape protruding toward the radially outer side, and the inner side surface of each elastic deformation portion 6 facing radially inward is in a curved shape recessed toward the radially outer side. Thus, each elastic deformation portion 6 can be elastically deformed with a smaller force.

[0181] The respective elastic deformation portions 6 are arranged at substantially equal intervals in the circumferential direction. The outer ends of the respective elastic deformation portions 6 are integrally connected to both ends of the respective base portions 7. The inner ends of the respective elastic deformation portions 6 are integrally connected to both ends of the respective support portions 5. That is, the support portion 5 extends in the circumferential direction in such a manner as to connect the inner ends of the adjacent elastic deformation portions 6 to each other, and the base portion 7 extends in the circumferential direction in such a manner as to connect the outer ends of the adjacent elastic deformation portions 6 to each other. Thus, the support portion 5 is provided at the inner end of the elastic deformation portion 6, and the base portion 7 is provided at the outer end of the elastic deformation portion 6. The annular support member 4 is connected in a zigzag shape in the order of the base portion 7, the elastic deformation portion 6, the support portion 5, the elastic deformation portion 6, and the base portion 7. The annular support member 4 is formed into an annular shape by repeating the above order.

[0182] In addition, in the present embodiment, a convex portion protruding radially inward from the inner peripheral surface of the front end hole 21 is constituted by the above-described support portion 5 and elastic deformation portion 6. A plurality of the convex portions are provided at intervals in the circumferential direction on the inner peripheral surface of the front end hole 21.

[0183] ·Inner side notch, outer side notch

[0184] An inner side notch 8 is formed between the respective support portions 5. The inner ends of the elastic deformation portions 6 are separated from each other through the inner side notch 8. An outer side notch 9 is formed between the respective base portions 7. The outer ends of the elastic deformation portions 6 are separated from each other through the outer side notch 9. The inner side notch 8 is provided at a position after advancing radially inward from the respective base portions 7 along the elastic deformation portions 6 on both sides thereof. That is, the inner side notch 8 is disposed between a pair of elastic deformation portions 6 connected to both ends of the base portion 7 and adjacent in the circumferential direction, and opens toward both sides in the front-rear direction and radially inward. The outer side notch 9 is provided at a position after advancing radially outward from the respective support portions 5 along the elastic deformation portions 6 on both sides thereof. That is, the outer side notch 9 is disposed between a pair of elastic deformation portions 6 connected to both ends of the support portion 5 and adjacent in the circumferential direction, and opens toward both sides in the front-rear direction and radially outward.

[0185] The material forming the annular support member 4 is preferably a synthetic resin. As the synthetic resin, from the aspect of reducing the sliding resistance between the writing body 3 and the support portion 5, for example, relatively hard synthetic resins such as polyoxymethylene, polycarbonate, polypropylene, polyethylene, and polyethylene terephthalate are preferred. In addition, in addition to this, as the material forming the annular support member 4, a synthetic resin having rubber elasticity (for example, relatively soft synthetic resins such as silicone rubber, nitrile rubber, ethylene-propylene-diene rubber, butyl rubber, chloroprene rubber, acrylonitrile-butadiene rubber, polyurethane rubber, fluororubber, polysulfide rubber, olefin-based thermoplastic elastomer, and styrene-based thermoplastic elastomer) may also be used.

[0186] As Figure 12 and Figure 15 shown, a spring 10 (compression coil spring) is accommodated inside the front end portion of the pen barrel 2. The front end of the spring 10 is fixed to the inner wall behind the front end hole 21 of the pen barrel 2, and the rear end of the spring 10 is fixed to the engaging portion of the writing body 3 (the engaging portion of the nib holding cylinder 32). The writing body 3 is urged rearward by the spring 10. A telescopic mechanism is provided inside the pen barrel 2, and this telescopic mechanism moves the writing body 3 forward against the rearward urging force of the spring 10.

[0187] As Figure 11 shown, the telescopic mechanism is a side-sliding type in which the nib 31 is telescoped from the front end hole 21 by sliding an operation portion (for example, a pen clip 11) provided on the side surface of the pen barrel 2 forward. As the telescopic mechanism, in addition to this, for example, a rear-end push type or a rotary type may also be cited. The rear-end push type is a method in which the nib 31 is telescoped from the front end hole 21 by pressing an operation portion provided at the rear end of the pen barrel 2 forward. In addition, the rotary type is a method in which the nib 31 is telescoped from the front end hole 21 by rotating an operation portion provided on the outer surface of the pen barrel 2.

[0188] · Writing body

[0189] The writing body 3 includes: a nib 31 (ballpoint pen nib), disposed at the front end portion of the writing body 3; a nib holding cylinder 32, in which the nib 31 is assembled; and an ink containing cylinder 33, in which the nib holding cylinder 32 is assembled.

[0190] The nib 31 is formed of a ballpoint pen nib. The ballpoint pen nib is composed of a main body and a ball. The main body is formed of a cylindrical body made of metal (for example, stainless steel), and the ball is rotatably held at the front end of the main body. The front end portion of the main body is tapered, and a straight cylindrical outer peripheral surface is formed behind the front end portion of the main body. It should be noted that an elastic body (for example, a spring) that urges the ball forward may also be accommodated inside the main body of the ballpoint pen nib.

[0191] The outer diameter of the straight cylindrical outer peripheral surface of the ballpoint pen tip that protrudes forward from the pen tip holding cylinder 32 is set to be slightly larger than the inner diameter of the support portion 5 of the annular support member 4 fitted to the inner peripheral surface of the front end hole 21 (i.e., the diameter of the virtual inscribed circle tangent to each support portion 5). Thus, the straight cylindrical outer peripheral surface of the ballpoint pen tip and each support portion 5 can slide in the front-rear direction in a crimped state.

[0192] A locking portion formed by a forward stepped portion is provided on the outer surface of the pen tip holding cylinder 32, and the rear end of the spring 10 is locked to this locking portion.

[0193] The ink containing cylinder 33 is a straight cylindrical barrel, obtained by extrusion molding of synthetic resin (e.g., polypropylene). Ink is contained in the ink containing cylinder 33. The ink in the ink containing cylinder 33 passes through the pen tip holding cylinder 32 and is supplied into the ballpoint pen tip, and is discharged to the outside as the ball at the front end of the ballpoint pen tip rotates. It should be noted that, in addition, for example, there can be cited a configuration in which the pen tip holding cylinder 32 and the ink containing cylinder 33 are integrally formed and the ink containing cylinder 33 also serves as the pen tip holding cylinder 32, or a configuration in which the ink containing cylinder 33 is directly fixed to the pen tip 31, etc.

[0194] · Pen tip retracted state ( Figure 12 )

[0195] As Figure 12 shown, in the state where the pen tip 31 (ballpoint pen tip) is retracted into the pen barrel 2 (when not writing), the outer peripheral surface of the ballpoint pen tip and each support portion 5 of the annular support member 4 fitted to the inner peripheral surface of the front end hole 21 of the pen barrel 2 are in a non-contact state.

[0196] · Pen tip protruding state ( Figure 15 )

[0197] From Figure 12 the state where the pen tip 31 (ballpoint pen tip) is retracted into the pen barrel 2, operate the telescopic mechanism, so as to move the writing body 3 forward against the rearward force of the spring 10. Thus, as Figure 15 shown, it becomes a state where the ballpoint pen tip protrudes from the front end hole 21 to the outside (a state where writing is possible, Figure? ). In the process of changing from the pen tip retracted state shown in Figure 12 to the pen tip protruding state shown in Figure 15 , each support portion 5 and the outer peripheral surface of the front end portion of the writing body 3 (the straight cylindrical outer peripheral surface of the ballpoint pen tip) slide in the front-rear direction.

[0198] In the state where the pen tip protrudes, the outer peripheral surface of the straight cylindrical shape of the ballpoint pen tip is in a press-contact state with each support portion 5, and each support portion 5 elastically deforms (moves) in the diameter-expanding direction by a small force. That is, the support portion 5 can move in the diameter-expanding direction by contact with the outer peripheral surface of the writing body 3. Thereby, it is possible to reliably prevent the shaking of the pen tip 31 during writing, and to reduce the sliding resistance between the pen tip 31 and the support portion 5, so that a smooth telescopic operation of the pen tip 31 can be performed.

[0199] The telescopic writing instrument 1 of the present embodiment shows, for example, the first aspect, the second aspect, the third aspect, the fourth aspect, the fifth aspect, etc. of the present invention. However, the telescopic writing instrument 1 of the present embodiment is not limited to these aspects.

[0200] <Fourth Embodiment>

[0201] Figure 14 , Figures 17 to 19 The telescopic writing instrument 1 (1D) of the fourth embodiment of the present invention is shown. It should be noted that in the present embodiment, the same components as those in the foregoing embodiments may be denoted by the same names, reference numerals, etc., and the description thereof may be omitted. In addition, unless otherwise specified, the definition of directions and the like are also the same as those in the foregoing embodiments.

[0202] ·Barrel

[0203] The barrel 2 is a cylindrical body formed of a synthetic resin (for example, polycarbonate) in the same manner as in the third embodiment. The barrel 2 includes: a tapered front shaft having a front end hole 21 at the front end; an intermediate shaft that is detachably screwed to the rear end portion of the front shaft; and a rear shaft that is coupled to the rear end portion of the intermediate shaft. The writing body 3 is accommodated in the barrel 2 so as to be movable back and forth. A tapered outer surface is formed at the front end portion (front shaft) of the barrel 2, and a front end hole 21 penetrating in the axial direction is formed at the front end thereof. The pen tip 31 (ballpoint pen tip) of the writing body 3 is configured to be able to telescopically extend from the front end hole 21 of the barrel 2.

[0204] ·Ring-shaped support member (Mode 1)

[0205] An annular support member (annular support portion) 4 is fitted to the inner peripheral surface of the middle portion (middle axis) of the pen barrel 2. Specifically, two annular protrusions are formed on the inner peripheral surface of the middle portion of the pen barrel 2 in the front and rear directions, and an annular groove 22 is formed between the two annular protrusions. The annular support member 4 is fitted into the annular groove 22. Specifically, in the present embodiment, a pair of annular protrusions that protrude radially inward from the inner peripheral surface of the middle portion of the pen barrel 2 and extend in the circumferential direction are provided at intervals in the front-rear direction. Further, the front surface 22a of the annular groove 22 is disposed on the wall portion (rear wall) of one of the pair of annular protrusions located on the front side. In addition, the rear surface 22b of the annular groove 22 is disposed on the wall portion (front wall) of the other annular protrusion located on the rear side of the pair of annular protrusions. Further, the bottom surface 22c of the annular groove 22 is disposed between the pair of annular protrusions and is formed to be more recessed radially outward than the front surface 22a and the rear surface 22b. The annular support member 4 is clamped front and rear by the front surface 22a and the rear surface 22b of the annular groove 22 and is press-fitted to the bottom surface 22c of the annular groove 22. According to the present embodiment, when assembling the retractable writing instrument 1, the operation is easy whether the annular support member 4 is assembled into the annular groove 22 from the front side or the annular support member 4 is assembled into the annular groove 22 from the rear side. Further, the annular support member 4 disposed in the annular groove 22 is clamped from the front and rear directions by the front surface 22a and the rear surface 22b, and thus the movement of the annular support member 4 in the front-rear direction from the annular groove 22 is restricted. Therefore, the annular support member 4 is stably held in the annular groove 22.

[0206] As ​ shown, the annular support member 4 is, like the third embodiment, constituted by integrally connecting a plurality of (for example, five) support portions 5, a plurality of (for example, five) base portions 7, and a plurality of (for example, ten) elastic deformation portions 6. The annular support member 4 is a member integrally formed in a ring shape. In the shape of the portion of the annular support member 4 other than the outer notch 9 and the inner notch 8, the cross section (that is, the longitudinal section) obtained by cutting between the inner side and the outer side along the axial direction and the radial direction has a circular shape.

[0207] · Support portion

[0208] Each support portion 5 is provided to extend in the circumferential direction. Each support portion 5 is arranged at equal intervals in a circumferential shape. The inner side surface of each support portion 5 becomes a concave curved surface when viewed in the front view and is press-fitted to the outer peripheral surface of the writing body 3 (the straight cylindrical outer peripheral surface of the ink storage cylinder 33) in a line shape extending in the circumferential direction. The inner side surface of each support portion 5 is disposed on a virtual inscribed circle when viewed in the front view. The diameter of the virtual inscribed circle is set to be slightly smaller than the outer diameter of the outer peripheral surface of the writing body 3 (the straight cylindrical outer peripheral surface of the ink storage cylinder 33).

[0209] · Base portion

[0210] Each base 7 is arranged to extend circumferentially. Each base 7 is arranged at equal intervals in a circumferential shape. The outer side surface of each base 7 forms a convex curved surface when viewed from the front, and is in line contact with the bottom surface 22c of the annular groove 22 of the pen barrel 2 along a line extending circumferentially. The outer side surface of each base 7 is arranged on a virtual circumscribed circle when viewed from the front. The diameter of the virtual circumscribed circle is set to be slightly larger than the inner diameter of the bottom surface 22c of the annular groove 22 of the pen barrel 2. The base 7 is in line contact with the bottom surface 22c of the annular groove 22 and is clamped front and back by the front surface 22a and the rear surface 22b of the annular groove 22.

[0211] ·Elastic deformation part

[0212] Each elastic deformation part 6 projects from the inner surface of the base 7 in a direction deviating from the central direction (centripetal direction) of the annular support member 4. That is, each elastic deformation part 6 projects from the inner surface of the base 7 in a direction not facing the center of the annular support member 4. Each elastic deformation part 6 is formed such that the center M of the annular support member 4 does not exist on the extension line of the virtual straight line P connecting the center of the inner ends of each elastic deformation part 6 and the center of the outer ends of each elastic deformation part 6. Each elastic deformation part 6 elastically deforms in a manner of tilting radially outward when the outer peripheral surface of the writing body 3 comes into contact with the support part 5. Through the elastic deformation of each elastic deformation part 6, the radial distance between the support part 5 and the base 7 becomes smaller.

[0213] Each elastic deformation part 6 has a curved shape that is convex on the outside and concave on the inside. Thus, each elastic deformation part 6 can be elastically deformed with a smaller force.

[0214] Each elastic deformation part 6 is arranged at substantially equal intervals in a circumferential shape. The outer ends of each elastic deformation part 6 are integrally connected to both ends of each base 7. The inner ends of each elastic deformation part 6 are integrally connected to both ends of each support part 5.

[0215] ·Inner notch, outer notch

[0216] Inner notches 8 are formed between the respective supporting portions 5. The inner ends of the elastic deformation portions 6 are separated from each other through the inner notches 8. The inner notches 8 are provided to open the inner sides of the elastic deformation portions 6 inward, whereby a plurality of the supporting portions 5 are circumferentially and dispersedly arranged. More specifically, the plurality of inner notches 8 are locally provided in such a manner that the inner ends of the adjacent elastic deformation portions 6 are not connected to each other, and a plurality of the supporting portions 5 are circumferentially and dispersedly arranged. In addition, outer notches 9 are formed between the respective base portions 7. The outer ends of the elastic deformation portions 6 are separated from each other through the outer notches 9. The outer notches 9 are provided to open the outer sides of the elastic deformation portions 6 outward, whereby a plurality of the base portions 7 are circumferentially and dispersedly arranged. More specifically, the plurality of outer notches 9 are locally provided in such a manner that the outer ends of the adjacent elastic deformation portions 6 are not connected to each other, and a plurality of the base portions 7 are circumferentially and dispersedly arranged. The inner notches 8 are provided at positions after advancing radially inward from the respective base portions 7 along the elastic deformation portions 6 on both sides thereof. The outer notches 9 are provided at positions after advancing radially outward from the respective supporting portions 5 along the elastic deformation portions 6 on both sides thereof. The annular support member 4 is connected in a zigzag shape in the order of the base portion 7, the elastic deformation portion 6, the supporting portion 5, the elastic deformation portion 6, and the base portion 7.

[0217] The material forming the annular support member 4 is preferably a synthetic resin. As the synthetic resin, from the aspect of reducing the sliding resistance between the writing body 3 and the supporting portion 5, for example, a relatively hard synthetic resin such as polyoxymethylene, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, etc. is preferably used. In addition, in addition to this, as the material forming the annular support member 4, a synthetic resin having rubber elasticity (for example, a relatively soft synthetic resin such as silicone rubber, nitrile rubber, ethylene - propylene - diene rubber, butyl rubber, chloroprene rubber, acrylonitrile - butadiene rubber, polyurethane rubber, fluororubber, polysulfide rubber, olefin - based thermoplastic elastomer, styrene - based thermoplastic elastomer, etc.) may also be used.

[0218] Inside the front end portion of the pen barrel 2, a spring 10 (compression coil spring) is accommodated in the same manner as in the third embodiment. The front end of the spring 10 is fixed to the inner wall behind the front end hole 21 of the pen barrel 2, and the rear end of the spring 10 is fixed to the engaging portion of the writing body 3 (the engaging portion of the nib holding cylinder 32). The writing body 3 is urged rearward by the spring 10. A telescopic mechanism is provided inside the pen barrel 2, and the telescopic mechanism moves the writing body 3 forward against the rearward urging force of the spring 10.

[0219] As ​As shown, the telescopic mechanism is a side-sliding type in which the tip 31 is telescoped in and out of the front end hole 21 by sliding an operation portion (such as the clip 11) provided on the side surface of the pen barrel 2 forward. As the telescopic mechanism, in addition, for example, a rear push type or a rotary type can also be cited. The rear push type is a method in which the tip 31 is telescoped in and out of the front end hole 21 by pressing an operation portion provided at the rear end of the pen barrel 2 forward. In addition, the rotary type is a method in which the tip 31 is telescoped in and out of the front end hole 21 by rotating an operation portion provided on the outer surface of the pen barrel 2.

[0220] · Handwriting style

[0221] The writing body 3 includes, in the same manner as the third embodiment: a tip 31 (a ballpoint pen tip) disposed at the front end of the writing body 3; a tip holder 32 for fitting the tip 31; and an ink cartridge 33 for fitting the tip holder 32.

[0222] The tip 31 is composed of a ballpoint pen tip. The ballpoint pen tip is composed of a main body and a ball. The main body is composed of a cylindrical body made of metal (such as stainless steel), and the ball is rotatably held at the front end of the main body. It should be noted that an elastic body (such as a spring) that applies a forward force to the ball may be accommodated in the main body of the ballpoint pen tip.

[0223] A locking portion formed by a forward stepped portion is provided on the outer surface of the tip holder 32, and the rear end of the spring 10 is locked to the locking portion.

[0224] The ink cartridge 33 is a cylindrical body having a straight cylindrical outer peripheral surface and is obtained by extrusion molding of synthetic resin (such as polypropylene). Ink is accommodated in the ink cartridge 33. The ink in the ink cartridge 33 passes through the inside of the tip holder 32 and is supplied into the ballpoint pen tip, and is discharged to the outside as the ball at the front end of the ballpoint pen tip rotates. It should be noted that, in addition, for example, a configuration in which the tip holder 32 and the ink cartridge 33 are integrally formed and the ink cartridge 33 also serves as the tip holder 32 or a configuration in which the ink cartridge 33 is directly fixed to the tip 31 can be cited.

[0225] As ​ As shown, each support portion 5 is always in pressure contact with the outer peripheral surface of the middle portion of the writing body 3 (the outer peripheral surface of the ink cartridge 33), and each support portion 5 and the outer peripheral surface of the middle portion of the writing body 3 (the outer peripheral surface of the ink cartridge 33) slide in the front-rear direction. That is, in the present embodiment, regardless of whether the tip is retracted or protruding, the annular support member (annular support portion) 4 provided on the inner peripheral surface of the pen barrel 2 is configured to support the outer peripheral surface of the writing body 3.

[0226] In the telescopic writing instrument 1 of the present embodiment, the straight cylindrical outer peripheral surface of the writing body 3 and each support portion 5 are in a press-contact state, and each support portion 5 elastically deforms in the diameter-expanding direction by a small force. That is, the support portion 5 can move in the diameter-expanding direction by contact with the outer peripheral surface of the writing body 3. Thereby, it is possible to reliably prevent the shaking of the writing body 3 during writing, and to reduce the sliding resistance between the writing body 3 and the support portion 5, so that a smooth telescopic movement of the nib 31 can be performed. In addition, in the present embodiment, the shaking of the writing body 3 in the pen barrel 2 can also be suppressed during non-writing, so that a high-class feeling can be given to the product and the added value can be improved.

[0227] The telescopic writing instrument 1 of the present embodiment shows, for example, the first aspect, the second aspect, the third aspect, the fourth aspect, and the fifth aspect of the present invention, etc. However, the telescopic writing instrument 1 of the present embodiment is not limited to these aspects.

[0228] <Other mode of the annular support member (Mode 2)>

[0229] ​ Shows another mode (Mode 2) of the annular support member (annular support portion) 4 for the telescopic writing instrument 1 of the present invention.

[0230] It should be noted that the other modes 2 to 5 of the annular support member 4 described below can also be renamed as the first modification example to the fourth modification example of the annular support member 4 (Mode 1) of the present embodiment. In addition, in the drawings of these respective modes (respective modification examples), the same reference numerals are given to the same configurations as those of the foregoing embodiment, and mainly the differences will be described in the following content.

[0231] The annular support member 4 is a structure in which a plurality of (for example, four) support portions 5, a plurality of (for example, four) base portions 7, and a plurality of (for example, four) elastic deformation portions 6 are integrally connected. The annular support member 4 is a member integrally formed in a ring shape. In the shape of the portion of the annular support member 4 other than the outer notch 9 and the inner notch 8, a cross section (that is, a longitudinal section) obtained by cutting longitudinally between the inner side and the outer side in the axial direction and in the radial direction has a circular shape.

[0232] Here, in ​In the front view shown in (b), a specified rotational direction in the circumferential direction around the central axis O is defined as one side in the circumferential direction (+θ side), and a rotational direction opposite to the specified rotational direction in the circumferential direction around the central axis O is defined as the other side in the circumferential direction (−θ side). In the illustrated example, the clockwise rotational direction around the central axis O corresponds to one side in the circumferential direction (+θ side), and the counterclockwise rotational direction corresponds to the other side in the circumferential direction (−θ side). However, it is not limited thereto, and it may also be set such that the counterclockwise rotational direction around the central axis O corresponds to one side in the circumferential direction (+θ side), and the clockwise rotational direction corresponds to the other side in the circumferential direction (−θ side).

[0233] Each elastic deformation portion 6 extends toward one side in the circumferential direction (+θ side) as it approaches the radially outer side. The inner end portions of the respective elastic deformation portions 6 are integrally connected to the circumferential one end portions (one side end portions) of the respective support portions 5. The circumferential other end portions (the other side end portions) of the respective support portions 5 are integrally connected to the circumferential one end portions (one side end portions) of the respective base portions 7. The circumferential other end portions (the other side end portions) of the respective base portions 7 are integrally connected to the outer end portions of the respective elastic deformation portions 6. The annular support member 4 is connected in a zigzag shape in the order of the elastic deformation portion 6, the support portion 5, the base portion 7, and the elastic deformation portion 6. The annular support member 4 is formed into an annular shape by repeating the above order.

[0234] · Support portion

[0235] Each support portion 5 extends in the circumferential direction. The respective support portions 5 are arranged at equal intervals in a circumferential shape. The inner side surface of each support portion 5 becomes a concave curved surface in the front view and is in line contact with the outer peripheral surface of the writing body 3 (the straight cylindrical outer peripheral surface of the ballpoint pen tip or the straight cylindrical outer peripheral surface of the ink storage cylinder 33) extending in the circumferential direction. The inner side surface of each support portion 5 is arranged on a virtual inscribed circle in the front view. The diameter of the virtual inscribed circle is set to be slightly smaller than the outer diameter of the outer peripheral surface of the writing body 3 (the straight cylindrical outer peripheral surface of the ballpoint pen tip or the straight cylindrical outer peripheral surface of the ink storage cylinder 33).

[0236] · Base portion

[0237] Each base portion 7 extends in the circumferential direction. The respective base portions 7 are arranged at equal intervals in a circumferential shape. The outer side surface of each base portion 7 becomes a convex curved surface in the front view and is in line contact with the bottom surface 22c of the annular groove 22 of the pen barrel 2 extending in the circumferential direction. The outer side surface of each base portion 7 is arranged on a virtual circumscribed circle in the front view. The diameter of the virtual circumscribed circle is set to be slightly larger than the inner diameter of the bottom surface 22c of the annular groove 22 of the pen barrel 2.

[0238] · Elastic deformation portion

[0239] Each elastic deformation part 6 is arranged at substantially equal intervals in a circumferential shape. Each elastic deformation part 6 protrudes from the inner surface of the base part 7 in a direction deviating from the central direction (centripetal direction) of the annular support member 4. That is, each elastic deformation part 6 protrudes from the inner surface of the base part 7 in a direction not facing the center of the annular support member 4. Each elastic deformation part 6 is formed such that the center M (central axis O) of the annular support member 4 does not exist on the extension line of the virtual straight line P connecting the center of the inner end of each elastic deformation part 6 and the center of the outer end of each elastic deformation part 6. When the outer peripheral surface of the writing body 3 comes into contact with the support part 5, each elastic deformation part 6 elastically deforms in a manner of tilting radially outward. Through the elastic deformation of each of the elastic deformation parts 6, the radial distance between the support part 5 and the base part 7 becomes smaller.

[0240] Each elastic deformation part 6 has a curved shape that is convex on the outside and concave on the inside. Thus, each elastic deformation part 6 can be elastically deformed with a smaller force.

[0241] ·Inner notch, outer notch

[0242] Inner notches 8 are formed between the respective support parts 5. Through the inner notches 8, the inner ends of the elastic deformation parts 6 are separated from the ends on the other circumferential side (-θ side) of the support parts 5. Outer notches 9 are formed between the respective base parts 7. Through the outer notches 9, the outer ends of the elastic deformation parts 6 are separated from the ends on one circumferential side (+θ side) of the base parts 7. The inner notches 8 are provided on the inner sides of the respective base parts 7 and the inner sides of the elastic deformation parts 6. That is, the inner notches 8 are arranged radially inward of the mutually connected base parts 7 and the elastic deformation parts 6 and open toward both sides in the front-rear direction and radially inward. The outer notches 9 are provided on the outer sides of the respective support parts 5 and the outer sides of the elastic deformation parts 6. That is, the outer notches 9 are arranged radially outward of the mutually connected support parts 5 and the elastic deformation parts 6 and open toward both sides in the front-rear direction and radially outward.

[0243] The material constituting the annular support member 4 is preferably a synthetic resin. As the synthetic resin, from the aspect of reducing the sliding resistance between the writing body 3 and the support part 5, for example, relatively hard synthetic resins such as polyoxymethylene, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, etc. are preferred. In addition, in addition to this, as the material constituting the annular support member 4, a synthetic resin having rubber elasticity (for example, relatively soft synthetic resins such as silicone rubber, nitrile rubber, ethylene-propylene-diene rubber, butyl rubber, chloroprene rubber, acrylonitrile-butadiene rubber, polyurethane rubber, fluororubber, polysulfide rubber, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, etc.) can also be used.

[0244] The annular support member 4 (method 2) of this embodiment is applied to the telescopic writing instrument 1 of the third embodiment of the present invention and is mounted on the inner circumferential surface of the front end hole 21 of the pen barrel 2. Furthermore, the annular support member 4 (method 2) of this embodiment is applied to the telescopic writing instrument 1 of the fourth embodiment of the present invention and is mounted on the inner circumferential surface of the intermediate portion of the pen barrel 2. When the annular support member 4 (method 2) of this embodiment is applied to the third embodiment and the fourth embodiment of the present invention, for example, the first, second, third, and seventh embodiments of the present invention are represented. However, the telescopic writing instrument 1 of this embodiment is not limited to these embodiments.

[0245] <Other forms of annular support member (Form 3)>

[0246] ​ 9 shows another embodiment (embodiment 3) of the annular support member (annular support portion) 4 used in the retractable writing instrument 1 of the present invention.

[0247] The annular support member 4 is constructed by integrally connecting an annular base portion 7 with a plurality (e.g., twenty) of elastically deformable portions 6, with support portions 5 formed at the inner end of each elastically deformable portion 6. Specifically, in this embodiment (Embodiment 3), the annular support member 4 includes a single base portion 7, a plurality of elastically deformable portions 6, and a plurality of support portions 5.

[0248] Base

[0249] In the base 7 of the annular support member 4, the base 7 is formed into an annular shape and has a circular cross-section. In addition, in the base 7 of the annular support member 4, the cross-section (that is, the longitudinal cross-section) obtained by cutting between the inner side and the outer side in the axial direction and the radial direction has a circular shape. The outer side surface of the base 7 is circular when observed from the front, and is crimped to the bottom surface 22c of the annular groove 22 of the pen body 2 in a linear manner extending in the circumferential direction. The outer diameter of the base 7 is set in a manner slightly larger than the inner diameter of the bottom surface 22c of the annular groove 22 of the pen body 2. The base 7 is clamped front and back by the front surface 22a and the rear surface 22b of the annular groove 22, and is crimped to the bottom surface 22c of the annular groove 22.

[0250] Elastic deformation part

[0251] The respective elastic deformation portions 6 are arranged at substantially equal intervals in the circumferential direction. Each elastic deformation portion 6 protrudes from the inner surface of the base portion 7 in a direction deviated from the central direction (centripetal direction) of the annular support member 4. That is, each elastic deformation portion 6 protrudes from the inner surface of the base portion 7 in a direction not facing the center of the annular support member 4. Each elastic deformation portion 6 is formed such that the center M (central axis O) of the annular support member 4 does not exist on the extension line of the virtual straight line P connecting the center of the inner ends of the respective elastic deformation portions 6 and the center of the outer ends of the respective elastic deformation portions 6. Each elastic deformation portion 6 extends in the circumferential direction as it approaches the radial direction. Each elastic deformation portion 6 elastically deforms in a manner of tilting radially outward when the outer peripheral surface of the writing body 3 comes into contact with the support portion 5. Through the elastic deformation of the respective elastic deformation portions 6, the radial distance between the support portion 5 and the base portion 7 becomes smaller.

[0252] · Support portion

[0253] The outer ends of the respective elastic deformation portions 6 are integrally connected to the base portion 7. The inner ends of the respective elastic deformation portions 6 are all separated from each other. The inner ends of the respective elastic deformation portions 6 constitute the support portion 5. Each support portion 5 is, for example, in the shape of a hemispherical surface protruding radially inward.

[0254] The respective support portions 5 are arranged at equal intervals in the circumferential direction. The respective support portions 5 (the inner ends of the respective elastic deformation portions 6) are pressed against the outer peripheral surface of the writing body 3 (the straight cylindrical outer peripheral surface of the ballpoint pen tip or the straight cylindrical outer peripheral surface of the ink storage cylinder 33). The diameter of the virtual inscribed circle tangent to the respective support portions 5 (the inner ends of the respective elastic deformation portions 6) is set to be slightly smaller than the outer diameter of the outer peripheral surface of the writing body 3 (the straight cylindrical outer peripheral surface of the ballpoint pen tip or the straight cylindrical outer peripheral surface of the ink storage cylinder 33).

[0255] The material constituting the annular support member 4 is preferably a synthetic resin. As the synthetic resin, from the aspect of reducing the sliding resistance between the writing body 3 and the support portion 5, for example, relatively hard synthetic resins such as polyoxymethylene, polycarbonate, polypropylene, polyethylene, and polyethylene terephthalate are preferred. In addition, in addition to this, as the material constituting the annular support member 4, a synthetic resin having rubber elasticity (for example, relatively soft synthetic resins such as silicone rubber, nitrile rubber, ethylene - propylene - diene rubber, butyl rubber, chloroprene rubber, acrylonitrile - butadiene rubber, polyurethane rubber, fluororubber, polysulfide rubber, olefin - based thermoplastic elastomer, and styrene - based thermoplastic elastomer) can also be used.

[0256] The annular support member 4 (Form 3) of this embodiment is applied to the telescopic writing instrument 1 of the third embodiment of the present invention and is mounted on the inner circumferential surface of the front end hole 21 of the pen barrel 2. Furthermore, the annular support member 4 (Form 3) of this embodiment is applied to the telescopic writing instrument 1 of the fourth embodiment of the present invention and is mounted on the inner circumferential surface of the intermediate portion of the pen barrel 2. When the annular support member 4 (Form 3) of this embodiment is applied to the third and fourth embodiments of the present invention, for example, the first, second, and eighth embodiments of the present invention are represented. However, the telescopic writing instrument 1 of this embodiment is not limited to these embodiments.

[0257] <Other aspects of the annular support member (aspect 4)>

[0258] ​ 9 shows another embodiment (embodiment 4) of the annular support member (annular support portion) 4 used in the retractable writing instrument 1 of the present invention.

[0259] The annular support member 4 is composed of an annular base 7, multiple (e.g., three) elastically deformable portions 6, and an annular support portion 5, all connected in an integral manner. That is, in this embodiment (embodiment 4), the annular support member 4 includes one base 7, multiple elastically deformable portions 6, and one support portion 5.

[0260] Base

[0261] The base 7 of the annular support member 4 is formed into an annular shape. A longitudinal cross-section of the outer circumference of the base 7 (a cross-section taken along the axial direction and radially between the inner and outer sides) is a convex curved surface. A longitudinal cross-section of the inner circumference of the base 7 is a flat surface. Specifically, the inner circumference of the base 7, when viewed in longitudinal cross-section, is a straight line extending in the front-to-back direction.

[0262] The base 7 is pressed against the bottom surface 22c of the annular groove 22 of the pen body 2 in a linear shape extending in the circumferential direction. The outer diameter of the base 7 is set to be slightly larger than the inner diameter of the bottom surface 22c of the annular groove 22 of the pen body 2.

[0263] Elastic deformation part

[0264] Each elastic deformation portion 6 is plate-shaped. One of the pair of plate surfaces of the elastic deformation portion 6 facing radially inward and the other plate surface facing radially outward are each planar. The respective elastic deformation portions 6 are arranged at substantially equal intervals in the circumferential direction. Each elastic deformation portion 6 projects from the inner surface of the base portion 7 in a direction deviated from the central direction (centripetal direction) of the annular support member 4. That is, each elastic deformation portion 6 projects from the inner surface of the base portion 7 in a direction not facing the center of the annular support member 4. Each elastic deformation portion 6 is formed such that the center M (central axis O) of the annular support member 4 does not exist on the extension line of the virtual straight line P connecting the center of the inner end portion of each elastic deformation portion 6 and the center of the outer end portion of each elastic deformation portion 6. Each elastic deformation portion 6 extends in the circumferential direction as it approaches the radial direction. Each elastic deformation portion 6 elastically deforms in a manner of tilting radially outward when the outer peripheral surface of the writing body 3 comes into contact with the support portion 5.

[0265] · Support portion

[0266] The support portion 5 is formed in a ring shape. The inner end portions of the respective elastic deformation portions 6 are integrally connected to the outer peripheral surface of the support portion 5. The longitudinal section of the inner peripheral surface of the support portion 5 is a convex curved surface. The longitudinal section of the outer peripheral surface of the support portion 5 is a plane. Specifically, the outer peripheral surface of the support portion 5 is linear and extends in the front-rear direction when observed in longitudinal section. A plurality (for example, three) of arc-shaped gaps are formed by the outer peripheral surface of the annular support portion 5, the inner peripheral surface of the annular base portion 7, and the elastic deformation portions 6. It should be noted that the annular support member 4 is a member integrally formed in a ring shape. The shape of the portion of the annular support member 4 other than the arc-shaped gap has a circular cross-sectional shape.

[0267] The support portion 5 is pressed against the outer peripheral surface of the writing body 3 (the straight cylindrical outer peripheral surface of the ballpoint pen tip or the straight cylindrical outer peripheral surface of the ink storage cylinder 33). The inner diameter of the support portion 5 is set to be slightly smaller than the outer diameter of the outer peripheral surface of the writing body 3 (the straight cylindrical outer peripheral surface of the ballpoint pen tip or the straight cylindrical outer peripheral surface of the ink storage cylinder 33).

[0268] The material constituting the annular support member 4 is preferably a synthetic resin. As the synthetic resin, from the aspect of reducing the sliding resistance between the writing body 3 and the support portion 5, for example, a relatively hard synthetic resin such as polyoxymethylene, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, etc. is preferably used. In addition, in addition to this, as the material constituting the annular support member 4, a synthetic resin having rubber elasticity (for example, a relatively soft synthetic resin such as silicone rubber, nitrile rubber, ethylene-propylene-diene rubber, butyl rubber, chloroprene rubber, acrylonitrile-butadiene rubber, polyurethane rubber, fluororubber, polysulfide rubber, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, etc.) can also be used.

[0269] The annular support member 4 (Mode 4) of this mode is applied to the retractable writing instrument 1 of the third embodiment and is assembled on the inner peripheral surface of the front end hole 21 of the pen barrel 2. In addition, the annular support member 4 (Mode 4) of this mode is applied to the retractable writing instrument 1 of the fourth embodiment and is assembled on the inner peripheral surface of the middle part of the pen barrel 2.

[0270] When the annular support member 4 (Mode 4) of this mode is applied to the third embodiment of the present invention and the fourth embodiment of the present invention respectively, for example, it represents the first aspect, the second aspect, the fourth aspect, the sixth aspect, etc. of the present invention. However, the retractable writing instrument 1 of this embodiment is not limited to these aspects.

[0271] <Other mode of annular support member (Mode 5)>

[0272] ​ Another mode (Mode 5) of the annular support member (annular support portion) 4 for the retractable writing instrument 1 of the present invention is shown.

[0273] The annular support member 4 is composed of a single base portion 7 that is C-shaped when viewed from the front (arc-shaped with a circumference of 75% or more based on the circumference of a virtual circle) and a single elastic deformation portion 6 that connects the two end portions of the base portion 7. In addition, as described later, the inner peripheral surface of the base portion 7 constitutes the support portion 5. That is, in this mode (Mode 5), the annular support member 4 includes one base portion 7, one support portion 5, and one elastic deformation portion 6.

[0274] · Base portion

[0275] The base portion 7 has a circular shape in the longitudinal cross-section. The outer side surface of the base portion 7 is arc-shaped when viewed from the front.

[0276] · Elastic deformation portion

[0277] The elastic deformation portion 6 is composed of a wavy curved linear body and can be elastically deformed in the circumferential direction. The elastic deformation portion 6 has a portion that extends toward the radially inner side as it approaches one side in the circumferential direction and a portion that extends toward the radially outer side as it approaches one side in the circumferential direction. The portion that extends toward the radially inner side as it approaches one side in the circumferential direction and the portion that extends toward the radially outer side as it approaches one side in the circumferential direction are alternately arranged in the circumferential direction and are connected to each other.

[0278] · Support portion

[0279] The inner peripheral surface of the base portion 7 constitutes the support portion 5. The support portion 5 is pressed against the outer peripheral surface of the writing body 3 (the straight cylindrical outer peripheral surface of the ballpoint pen tip or the straight cylindrical outer peripheral surface of the ink storage cylinder 33). The inner diameter of the support portion 5 is set to be slightly smaller than the outer diameter of the outer peripheral surface of the writing body 3 (the straight cylindrical outer peripheral surface of the ballpoint pen tip or the straight cylindrical outer peripheral surface of the ink storage cylinder 33).

[0280] Thus, in this embodiment (Embodiment 5), the annular support member 4 includes at least one support portion 5 that is C-shaped when viewed in the front elevation and is connected to the inner peripheral surface of the pen barrel 2. In addition, the elastic deformation portion 6 is provided to connect the circumferential ends of the support portion 5, and the elastic deformation portion 6 can be elastically deformed in the circumferential direction. Although not particularly illustrated, when there are a plurality of support portions 5 (base portions 7) that are C-shaped when viewed in the front elevation, there are the same number of elastic deformation portions 6 as the support portions 5, and the support portions 5 and the elastic deformation portions 6 are alternately arranged in the circumferential direction. Moreover, each elastic deformation portion 6 connects between the respective support portions 5.

[0281] The material constituting the annular support member 4 is preferably a synthetic resin. As the synthetic resin, from the aspect of reducing the sliding resistance between the writing body 3 and the support portion 5, for example, relatively hard synthetic resins such as polyoxymethylene, polycarbonate, polypropylene, polyethylene, and polyethylene terephthalate are preferred. In addition, in addition to this, as the material constituting the annular support member 4, a synthetic resin having rubber elasticity (for example, relatively soft synthetic resins such as silicone rubber, nitrile rubber, ethylene - propylene - diene rubber, butyl rubber, chloroprene rubber, acrylonitrile - butadiene rubber, polyurethane rubber, fluororubber, polysulfide rubber, olefin - based thermoplastic elastomer, and styrene - based thermoplastic elastomer) may also be used.

[0282] The annular support member 4 (Embodiment 5) of this embodiment is applied to the telescopic writing instrument 1 of the third embodiment and is assembled to the inner peripheral surface of the front end hole 21 of the pen barrel 2. In addition, the annular support member 4 (Embodiment 5) of this embodiment is applied to the telescopic writing instrument 1 of the fourth embodiment and is assembled to the inner peripheral surface of the middle portion of the pen barrel 2. It should be noted that the fitting structure of the base portion 7 with the pen barrel 2 is different from that of the third embodiment and the fourth embodiment, and the base portion 7 is fitted to the bottom surface of the fitting recess in a non - contact state in such a manner that it is clamped front - and - rear to the pen barrel 2 and can be elastically deformed in the diameter - expanding direction. It should be noted that as long as there is a space between the outer peripheral surface of the base portion 7 and the bottom surface of the fitting recess that can allow the base portion 7 to be elastically deformed in the diameter - expanding direction, they may also be in partial contact. Other configurations are the same as those of the third embodiment and the fourth embodiment.

[0283] When the annular support member 4 (Embodiment 5) of this embodiment is applied to the third embodiment of the present invention and the fourth embodiment of the present invention respectively, for example, it represents the first aspect and the ninth aspect of the present invention, etc. However, the telescopic writing instrument 1 of this embodiment is not limited to these aspects.

[0284] <Fifth Embodiment>

[0285] ​Part (the front end portion of the pen barrel 2) of the telescopic writing instrument 1(1E) according to the fifth embodiment of the present invention is shown. It should be noted that in this embodiment, the same components as those in the foregoing embodiments may be denoted by the same names, reference numerals, etc., and their descriptions may be omitted. In addition, unless otherwise specified, the definition of directions, etc. is also the same as that in the foregoing embodiments.

[0286] · Ring-shaped support portion

[0287] In this embodiment, a ring-shaped support portion 45 is integrally formed on the inner peripheral surface of the front end hole 21 of the pen barrel 2. The ring-shaped support portion 45 has at least the elastic deformation portion 6 and the support portion 5 among the above-mentioned base portion 7, elastic deformation portion 6, and support portion 5. The elastic deformation portion 6 and the support portion 5 of the ring-shaped support portion 45 are arranged to protrude radially inward from the inner peripheral surface of the front end hole 21. In addition, the ring-shaped support portion 45 also has an inner notch 8. The ring-shaped support portion 45 in this embodiment may also be renamed as a ring-shaped support structure or the like.

[0288] The telescopic writing instrument 1 according to this embodiment can also achieve the same effects as those in the foregoing embodiments. Moreover, according to this embodiment, the number of components of the telescopic writing instrument 1 can be reduced, thereby reducing the manufacturing cost. In addition, there is no need for the operation of assembling the ring-shaped support portion 45 on the inner peripheral surface of the pen barrel 2, so it is easy to manufacture.

[0289] The present invention can also combine the various components described in the foregoing embodiments, etc. within the scope not departing from the gist of the present invention. In addition, additions, omissions, substitutions, and other changes can be made to the components. In addition, the present invention is not limited by the foregoing embodiments, etc., but is only limited by the claims.

[0290] Industrial applicability

[0291] According to the telescopic writing instrument of the present invention, both a smooth telescopic movement of the nib and a sufficient anti-vibration effect of the writing body during writing can be obtained. Therefore, it has industrial applicability.

[0292] Explanation of reference numerals

[0293] 1(1A, 1B, 1C, 1D, 1E): Telescopic writing instrument;

[0294] 10: Spring;

[0295] 11: Clip;

[0296] 2: Pen barrel;

[0297] 21: Front end hole;

[0298] 21a: Ring-shaped support portion;

[0299] 21b: Protrusion;

[0300] 21c: Concave portion;

[0301] 21d: Chamfered portion;

[0302] 22: Annular groove;

[0303] 3: Handwriting style;

[0304] 31: Nib (ballpoint pen nib);

[0305] 32: Nib holding cylinder;

[0306] 33: Ink containing cylinder;

[0307] 4: Annular support member (annular support portion);

[0308] 40: Nib (ballpoint pen nib);

[0309] 40a: Ball;

[0310] 41: Front portion;

[0311] 42: Intermediate portion;

[0312] 43: Rear portion;

[0313] 44: Step portion;

[0314] 45: Annular support portion;

[0315] 5: Support portion;

[0316] 50: Nib holding cylinder;

[0317] 51: Front side cylinder portion;

[0318] 52: Rear side cylinder portion;

[0319] 53: Flange portion;

[0320] 54: Assembly hole;

[0321] 6: Elastically deformable portion;

[0322] 60: Ink containing cylinder;

[0323] 7: Base portion;

[0324] 70: Annular elastomer;

[0325] 71: Annular support portion;

[0326] 72: Protrusion;

[0327] 73: Concave portion;

[0328] 8: Inner notch;

[0329] 80: Spring;

[0330] 9: Outer notch.

Claims

1. A telescopic writing instrument, characterized in that, Comprising: A pen shaft; and a writing body accommodated in the pen shaft in a manner capable of moving in the front-rear direction, The front end portion of the writing body is provided with a nib, The nib is configured to be able to extend and retract from the front end hole of the pen shaft, A ring-shaped support portion for supporting the outer peripheral surface of the writing body is provided on the inner peripheral surface of the pen shaft, The ring-shaped support portion has a support portion for supporting the outer peripheral surface of the writing body, The support portion can move in the diameter-expanding direction or the front-rear direction by contact with the outer peripheral surface of the writing body, The ring-shaped support portion partially has an elastic deformation portion, and the elastic deformation portion can preferentially elastically deform compared to other portions of the ring-shaped support portion when the outer peripheral surface of the writing body contacts the support portion.

2. The telescopic writing instrument according to claim 1, wherein, The ring-shaped support portion has: A base portion disposed on the inner peripheral surface of the pen shaft; A plurality of the elastic deformation portions extending inward from the base portion; and The support portion provided at the inner end of the elastic deformation portion, Each of the elastic deformation portions is formed to extend in a direction deviating from the center direction of the ring-shaped support portion, and when the outer peripheral surface of the writing body contacts the support portion, each of the elastic deformation portions tilts radially outward.

3. The telescopic writing instrument according to claim 2, wherein, An inner notch for opening the inner side of the elastic deformation portion inward is provided, and a plurality of the support portions are circumferentially and dispersedly arranged, An outer notch for opening the outer side of the elastic deformation portion outward is provided, and a plurality of the base portions are circumferentially and dispersedly arranged.

4. The telescopic writing instrument according to claim 2, wherein, The support portion is circumferentially extended and arranged in a manner of connecting the inner ends of adjacent elastic deformation portions to each other, The base portion is circumferentially extended and arranged in a manner of connecting the outer ends of adjacent elastic deformation portions to each other.

5. The telescopic writing instrument according to claim 4, wherein, A plurality of inner notches are locally provided in a manner of not connecting the inner ends of adjacent elastic deformation portions to each other, and a plurality of the support portions are circumferentially and dispersedly arranged, A plurality of outer notches are locally provided in a manner of not connecting the outer ends of adjacent elastic deformation portions to each other, and a plurality of the base portions are circumferentially and dispersedly arranged.

6. The telescopic writing instrument according to claim 4, wherein, The support portion is formed in a ring shape, and the base portion is formed in a ring shape.

7. The telescopic writing instrument according to claim 3, wherein, The inner end of each elastic deformation portion is connected to the circumferential one end of each support portion, The circumferential other end of each support portion is connected to the circumferential one end of each base portion, The circumferential other end of each base portion is connected to the outer end of each elastic deformation portion.

8. The telescopic writing instrument according to claim 2, wherein, The base portion is formed in a ring shape, The outer ends of each elastic deformation portion are connected to the base portion, The inner ends of each elastic deformation portion are all separated from each other, The inner ends of each elastic deformation portion constitute the support portion.

9. The telescopic writing instrument according to claim 1, wherein, The annular support portion includes at least one support portion that is C-shaped when viewed from the front and is connected to the inner peripheral surface of the pen barrel. The elastic deformation portion is provided to connect the ends of the support portion, and the elastic deformation portion can be elastically deformed in the circumferential direction.

10. The telescopic writing instrument according to claim 1, wherein The annular support portion is integrally formed on the inner peripheral surface of the pen barrel.

11. The telescopic writing instrument according to claim 1, wherein A plurality of convex portions are provided on the inner peripheral surface of the pen barrel in the circumferential direction, Each of the convex portions protrudes radially inward from the inner peripheral surface of the pen barrel, Each of the convex portions can be elastically deformed, In a state where the nib protrudes outward from the front end hole, the top of each of the convex portions is in contact with the outer peripheral surface of the writing body, and the inner peripheral surface of the pen barrel between adjacent convex portions and the outer peripheral surface of the writing body are in a non-contact state. The annular support portion includes the plurality of convex portions, The support portion is disposed on the top of each of the convex portions, The elastic deformation portion is disposed radially outside the support portion of each of the convex portions.

12. The telescopic writing instrument according to claim 11, wherein The top of each of the convex portions has a convex curved surface shape in a longitudinal section.

13. The telescopic writing instrument according to claim 11, wherein Each of the convex portions has flexibility in the front-rear direction.

14. The telescopic writing instrument according to any one of claims 11 to 13, wherein The annular support portion is provided on the inner surface of the front end hole, and each of the convex portions is integrally formed on the inner peripheral surface of the annular support portion.

15. A telescopic writing instrument, characterized in that, Comprising: A pen barrel; and a writing body that is accommodated in the pen barrel so as to be movable in the front-rear direction, A nib is provided at the front end of the writing body, The nib is configured to be telescopic from the front end hole of the pen barrel, A plurality of convex portions are provided on the inner peripheral surface of the front end hole in the circumferential direction, Each of the convex portions protrudes radially inward from the inner peripheral surface of the front end hole, Each of the convex portions can be elastically deformed, In a state where the nib protrudes outward from the front end hole, the top of each of the convex portions is in contact with the outer peripheral surface of the front end of the writing body, and the inner peripheral surface of the front end hole between adjacent convex portions and the outer peripheral surface of the front end of the writing body are in a non-contact state.

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