JP4851277B2 - Writing instrument - Google Patents

Description

The present invention relates to a writing instrument such as a ballpoint pen, a mechanical pencil, or a sign pen provided with a grip (elastic gripping member) made of an elastically deformable soft material for the purpose of preventing slipping at a gripping portion of a shaft tube.
In detail, it is related with the writing instrument which comprised the cylindrical grip over the substantially full length of the axial cylinder.

  Conventionally, as this type of writing instrument, a grip (cover) formed in a cylindrical shape with a soft elastic body such as rubber or synthetic resin or silicon rubber is inserted over substantially the entire length of the shaft cylinder (pen body). On the outer peripheral surface of the pen tip side, a grip portion having unevenness for preventing slipping is formed only in a portion corresponding to the gripping portion of the shaft tube, and a tip core body presser is attached to the tip of the grip portion on the rear end side. There is a type in which a grip of the grip is prevented by attaching a rear end core body presser and sandwiching the grip (see, for example, Patent Document 1).

However, according to such a conventional writing instrument, since the grip that covers the substantially entire length of the shaft cylinder has a cylindrical shape with the same outer diameter over the almost entire length, when gripping the grip, the thumb of the finger A gap is formed between the surface of the approximately U-shaped skin between the finger and the index finger, and the grip surface, and the fingertip portion of the thumb, index finger, and middle finger contacts the grip surface (grip portion having anti-slip unevenness). However, the gripping force of the finger that fluctuates greatly during writing concentrates only on the fingertip part, so there is a lack of fit to the finger, and it is easy to slip in the axial direction due to sweat etc. during writing, which makes it easy to get tired .
Furthermore, although there are individual differences in gripping methods at the time of writing, such individual differences in gripping methods cannot be dealt with.
JP-A-2-141295 (page 1-3, Fig. 1-3)

  The present invention has been made in view of the above-described conventional circumstances. An object of the present invention is to provide a writing instrument that is less fatigued while improving the fit and preventing slippage in the axial direction.

Means for solving the above problems, and barrel, in a writing instrument provided with the elastic deformable grip that is inserted into a cylindrical shape so as to cover the substantially axial entire length of the barrel, the grip is axially A raised portion formed on the entire outer peripheral surface of the substantially center, a front inclined curved surface portion that is smoothly and continuously reduced in diameter toward the front of the raised portion, and smoothly continues to the rear of the raised portion. The rear inclined curved surface portion reduced in diameter, the front cylindrical portion connected to the front end of the front inclined curved surface portion and extending forward, and the rear inclined curved surface portion connected to the rear end A rear cylindrical portion extending rearward, and the raised portion is formed in an inclined surface that slightly increases in diameter linearly as it goes forward, and the front side of the inclined surface is the front side And the rear inclined curved surface portion is connected to the rear end of the inclined surface. Thus, the diameter in the longitudinal section is expanded to a substantially trapezoidal shape, and the axial length of the front inclined curved surface portion, the raised portion, and the rear inclined curved surface portion is combined with the front cylindrical portion and the rear The front cylindrical portion and the rear cylindrical portion have substantially the same diameter, and the front cylindrical portion is larger than the axial length of the combined cylindrical portions. Is formed shorter in the axial direction than the cylindrical portion on the rear side .

In the first embodiment, a bulging portion is formed over the entire circumference on the outer circumferential surface at the substantially axial center of the grip that covers the substantially entire length of the shaft cylinder, and the inclined curved surface that continues smoothly from the bulging portion in the axial direction. Part was formed.
In the second embodiment, in addition to the configuration of the first embodiment, at least the surface portion of the grip is formed of a foam that can be elastically deformed.
Further, in the third mode, in addition to the configuration of the first or second mode, a protrusion for preventing misalignment is provided on the outer peripheral surface of the shaft tube, and the gripper moves in the axial direction and the peripheral direction with respect to the inner peripheral surface of the grip. Engaged impossible.
In the fourth embodiment, in addition to the configuration of the third embodiment, a plurality of the protrusions for preventing misalignment are arranged in the axial direction of the shaft cylinder, and a gap is appropriately formed between the protrusions for preventing misalignment.
Further, in the fifth mode, in addition to the configuration of any one of the first to fourth modes, the grip rear end is compressed and deformed by winding a locking band around the rear end of the grip. Thus, the shaft cylinder is locked so as not to move in the axial direction and the circumferential direction.
The said form has the following effects by the said structure.
According to a first embodiment, the outer peripheral surface of the substantially axial center of the grip to be coated on substantially the entire length of the barrel, and formed over a raised portion all around, smoothly continuous from the raised portions in the axial direction By forming the inclined curved surface part, when gripping the grip, the substantially U-shaped inter-finger skin surface from the thumb of the finger to the index finger fits with the surface shape of the raised part and the inclined curved surface part, respectively. The contact area between the skin surface of these fingers and the grip surface is increased, the shake of the entire barrel is greatly reduced, and the fingers and the grip are integrated, and the gripping force is gripped. , Not only the fingertip portions of the thumb, forefinger, and middle finger, but also the surface portions of the raised portion and the inclined curved surface portion are appropriately elastically deformed according to the shape of the fingers, and the gripping force is uniformly dispersed.
Therefore, it is possible to provide a writing instrument that is less likely to get tired while improving the fit and preventing slipping in the axial direction.
Therefore, compared with the prior art in which the entire grip covering the entire length of the shaft cylinder is a cylindrical shape having the same outer diameter over the entire length, the gripping force of the finger that varies greatly during writing can be uniformly dispersed and absorbed, The amount of muscle activity that moves the fingers is reduced, and as a result, the accumulation of fatigue when writing for a long time is reduced.
Furthermore, even if there are individual differences in how to grip during writing, there is also an action to correct the grip along the surface shape of the raised and inclined curved surface parts, so it corresponds to individual differences in gripping methods Thus, it is possible to provide a writing instrument that is less tiring for all users regardless of individual differences in gripping methods.

According to the second embodiment , at least the surface portion of the grip is formed of a foam that can be elastically deformed, so that the hardness becomes soft when gripping the grip, the gripping force is dispersed and absorbed appropriately, and the grip The overall weight can be reduced.
Therefore, it is possible to further reduce fatigue.
Therefore, the writing time can be further extended for a longer time.

According to a third aspect, by providing a displacement stop protrusion on the outer peripheral surface of the barrel, by immovable engaged to the inner circumferential surface in the axial direction and the circumferential direction of the grip, relative to the outer peripheral surface of the barrel Thus, the grip is held immovable in the axial direction and the circumferential direction.
Accordingly, it is possible to prevent the displacement of the grip.
Therefore, when knocking when the writing instrument is a knock-type mechanical pen, or when knocking when it is a knock-type ballpoint pen, the grip does not deform, and when assembling or maintenance, turning the tip etc. The grip is not deformed idly by the protrusion for preventing misalignment, and the grip can be prevented from being deformed in the axial direction and circumferential direction due to the idling, so that the durability of the grip is not lowered.
In particular, if this protrusion for preventing misalignment is disposed under the bulged portion and the inclined curved surface portion where the diameter of the grip is expanded, the gripping force is greater than the other portions from the bulged portion and the inclined curved surface portion when gripping the grip. Since it is strongly transmitted to the misalignment projection, the grip misalignment prevention function can be improved.

According to the fourth embodiment , a plurality of misalignment projections are arranged in the axial direction of the shaft cylinder, and an appropriate gap is formed between these misalignment projections so that the grip along the outer peripheral surface of the shaft cylinder is formed. When the annular protrusion and the vertical protrusion are overcome with the insertion, the frictional resistance with the grip is released, and the distal end portion in the insertion direction is difficult to turn inside.
Accordingly, the grip can be smoothly inserted into the shaft tube.
Therefore, the assembling work is facilitated, the manufacturing time can be shortened, and the cost can be reduced.

According to the fifth aspect , by winding a locking band around the rear end portion of the grip, compressing and deforming the grip rear end portion, and locking the shaft cylinder so as to be immovable in the axial direction and the circumferential direction, Even if the writing pressure acts on the grip, the rear end portion of the grip is not displaced forward along the outer peripheral surface of the shaft cylinder by the holding force of the locking band.
Therefore, even if the grip has a low hardness and easily deforms in accordance with the shape of the finger, it is possible to prevent a positional shift due to the writing pressure.
Therefore, since the grip is not deformed by the displacement of the grip, it is possible to prevent the grip durability from being lowered .

Next, the above-described embodiment will be described more specifically . As shown in FIGS. 1 to 4 , the writing instrument A is an elastic deformation that is inserted so as to cover the axial tube 1 and substantially the entire axial length of the axial tube 1. A possible cylindrical grip 2 and a front end 3 disposed on the front end side (front end side) of the grip 2, and the rear end or the rear end of the shaft tube 1 from the end side (rear end side) of the front end 3 The grip 2 is inserted and attached so as to cover the substantially entire length of the shaft tube 1 to the vicinity of the rear end.

  The grip 2 is a substantially cylindrical body formed of an elastically deformable material as a whole or at least only a surface portion thereof, or a rectangular tube body such as a triangular or polygonal cross section. A bulging portion 2a having a larger diameter than the other portions is formed over the entire circumference, and the front (downward in the drawing) from which the leading opening 3 is disposed from the bulging portion 2a and the backward in the opposite direction (upward in the drawing). The sloped curved surface portion 2b that smoothly continues toward both sides of each other is formed, or the sloped curved surface portion 2b that smoothly continues toward only the front side is formed.

  More specifically, the approximate center in the axial direction of the grip 2 is a position slightly ahead of the central position in the axial direction of the barrel 1, and a raised portion 2 a is arranged around this, and in the illustrated example, this raised portion 2 a. A pair of inclined curved surface portions 2b are arranged on both the front and rear sides of the plate to expand the diameter into a substantially trapezoidal longitudinal section.

  Further, as the molding material of the grip 2, for example, a low-hardness elastic material such as rubber, silicone rubber, or elastomer is used, or a low-hardness elastic material such as an elastically deformable foam made of a synthetic resin is used. And when the grip 2 is gripped, its hardness becomes flexible and the gripping force of the fingers (gripping force) is appropriately dispersed and absorbed, and the weight of the grip 2 can be reduced for a long time. Even if you use it for a long time, it is hard to get tired.

  When a foam that can be elastically deformed is used as the molding material of the grip 2, it is preferable because it is lightweight and has an appropriate frictional resistance. Particularly, for example, an ethylene-vinyl acetate copolymer (EVA) or a crosslinked polyethylene foam. , Foam of closed cell structure such as foam of vinyl chloride, foam of styrene elastomer, surface hardness (C type hardness meter, JIS K 6767) is 15 to 30 degrees, rebound resilience (JIS K 6400) is 15 % Or less and an apparent density (JIS K 6767) of 0.08 to 0.17 g / cm 3 is excellent in durability while having low resilience characteristics in which the gripping force is appropriately dispersed.

That is, when the surface hardness is 15 degrees or less, if the gripping force is strong, the grip 2 alone cannot be fully buffered and the shaft body 1 feels the hardness, the gripping stability is inferior and the finger moves and deforms. Further, when the surface hardness is 30 degrees or more, the grip 2 has a high stress when grasped, the deformation of the grip 2 in accordance with the shape of the finger hardly occurs, and fatigue tends to occur with writing over a long time.
When the resilience exceeds 15%, the foam has a large repulsion force against compression, so fatigue tends to accumulate when used for a long time, especially for users with low gripping force such as children and the elderly. Is difficult to use.
When the apparent density is lighter than 0.08, the strength of the foam itself also decreases, and it cannot be tolerated due to distortion and wear due to gripping force with use over a long period of time, and the apparent density is 0.17. If it is larger, the weight of the grip 2 becomes larger, which causes fatigue.

  The grip 2 formed of such an elastic material has an inner diameter slightly smaller than the outer diameter of the shaft tube 1 so that the grip 2 is not displaced with respect to the outer surface 1a of the shaft tube 1, In a state where the grip 2 is inserted along the surface 1a, the inner peripheral surface 2c of the grip 2 is brought into close contact with the outer peripheral surface 1a of the shaft cylinder so that a large frictional resistance is generated between them.

Further, the shaft cylinder outer peripheral surface 1a is provided with a slip-preventing protrusion that engages with the inner peripheral surface 2c of the grip 2 and is brought into close contact with the grip inner peripheral surface 2c. On the other hand, the grip 2 is held immovably in the axial direction and the circumferential direction.
In particular, if the protrusion for preventing misalignment is disposed below the bulged portion 2a and the inclined curved surface portion 2b with the diameter increased, the gripping force when the grip 2 is gripped is increased by the raised portion 2a and the inclined curved surface portion. Since it is transmitted from 2b to the protrusion for preventing displacement more strongly than other parts, the function of preventing the displacement of the grip 2 is improved.

  As a specific example of this misalignment projection, at least an annular projection 1b extending in the circumferential direction and a vertical projection 1c extending in the axial direction are provided. In the illustrated example, the vertical projection 1c is arranged at the center in the axial direction. A pair of annular projections 1b are arranged on the front and rear sides of this.

  The annular protrusion 1b and the vertical protrusion 1c are inclined so that their outer diameters gradually increase in the insertion direction of the grip 2 with respect to the outer peripheral surface 1a of the shaft cylinder 1 or are formed in an arc shape so that the outer periphery of the shaft cylinder When the grip 2 is inserted along the surface 1a, the annular protrusion 1b and the vertical protrusion 1c can be smoothly overcome.

Further, when a plurality of the annular protrusions 1b and the vertical protrusions 1c are arranged in the axial direction of the shaft cylinder 1, if each of them is continuously arranged in the axial direction, the grip 2 is inserted along the outer peripheral surface 1a of the shaft cylinder. As a result, a large frictional resistance continues when the annular protrusion 1b and the vertical protrusion 1c are overcome, so that the tip 2d in the insertion direction of the grip 2 turns inside and enters, so that there is a gap between the annular protrusion 1b and the vertical protrusion 1c. By forming gaps of appropriate dimensions, the frictional resistance with the grip 2 is released, and the tip end 2d in the insertion direction is prevented from turning inward.
According to the experiment, when the molding material of the grip 2 is the above-mentioned foam having the closed cell structure and elastically deformable, there is a gap of about 5 mm or more in the axial direction between the annular protrusion 1b and the vertical protrusion 1c. In this case, the grip 2 could be smoothly inserted without the tip 2d in the insertion direction being turned inward.
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 to 3, the first embodiment includes a front opening 3 threadedly connected to the outer peripheral surface of the front end portion of the shaft cylinder 1, and is formed of an elastically deformable foam having an closed cell structure. The elastic ring 4 is disposed between the grip 2 and the engaging band 5 is wound around the rear end 2e of the grip 2 to compress and deform the rear end 2e of the grip. In contrast, the locking band 5 is held so as not to move in the axial direction and the circumferential direction, and the locking band 5 is covered with a tail plug 6 to prevent the locking band 5 from expanding and coming off.

  The elastic ring 4 is made of rubber or an elastic synthetic resin material that is harder than the grip 2, and has a good grip feeling especially for a user who holds the vicinity of the tip 3 located on the distal end side of the shaft tube 1. In addition, the gripping hand is prevented from being displaced forward by the writing pressure.

  The locking band 5 is made of a material such as a synthetic resin such as polypropylene, and at least a part of the locking band 5 is formed into an elastically deformable band plate shape, and is wound around the outer peripheral surface of the grip 2 and then locked in an annular shape. As a result, the outer peripheral surface of the grip 2 is appropriately tightened and compressed and deformed, and the locking state of the locking band 5 is maintained using the elastic force, and the inner end portion of the locking band 5 is By locking the shaft tube 1 in the axial direction and the circumferential direction, the locking band 5 and the grip 2 are held so as to be immovable in the axial direction and the circumferential direction with respect to the shaft tube 1. .

  The locking band 5 will be described in detail. As shown in FIG. 3, the band plate portion 5a curved in an arc shape along the outer peripheral surface of the grip 2, and the band plate portion 5a are arranged at appropriate intervals in the circumferential direction. The elastically deformable thin portion 5b and the connecting portions 5c arranged near both ends in the circumferential direction of the strip plate portion 5a, and bend from the thin portion 5b to grip the strip plate portion 5a. 2, the whole of the locking band 5 is locked in an annular shape by winding the connecting portion 5c in the radial direction of the shaft tube 1 and fitting them together. .

  A locking projection 5d is provided on the inner periphery of the band plate portion 5a. The locking projection 5d and a recess 1d such as a through hole or a groove formed at the rear end of the shaft tube 1 are provided. By engaging the shaft cylinder 1 in the radial direction, the locking band 5 is locked to the shaft cylinder 1 so as not to move in the axial direction and the circumferential direction.

  Further, the band plate portion 5a is provided with a plurality of engaging recesses 5e such as through holes and grooves opened at appropriate intervals in the circumferential direction, and the grip 2 compressed and deformed by the locking band 5 is provided. By utilizing the elastic force of the engagement band 5, the surface of the engagement recess 5 e is bitten to prevent the grip band 2 from being displaced in the circumferential direction or the axial direction, and the engagement band 5. As a result, the amount of protrusion from the locking band 5 is reduced and the assembly is facilitated.

  Further, the locking band 5 locked in an annular shape is formed on the inner peripheral surface of the band plate portion 5a by forming a locking step portion 5f that bites into the outer peripheral surface of the grip 2 and engages in the axial direction. The outer peripheral surface of the grip 2 is prevented from being displaced at least forward from the inner peripheral surface.

  Then, the tail plug 6 is covered with the rear end portion of the shaft tube 1, and the inner diameter of the portion facing the locking band 5 is locked in an annular shape by the connecting portion 5c. The diameter of the locking band 5 is prevented from expanding so as to be substantially the same as the outer diameter of the band 5.

  Further, in the illustrated example, the tail plug 6 is integrally connected to the shaft cylinder 1 by screwing and connected to the outer peripheral surface of the rear end of the shaft cylinder 1, and is connected to the rear end opening of the tail plug 6. Detachably fits the makeup cap 6a as necessary.

  Furthermore, in the case of the illustrated example, the refill 7 is incorporated into the shaft cylinder 1 so that the writing tip 7a always protrudes from the tip 3 and the writing tip 7a is detachably covered with a cap 8. This shows the case of a ballpoint pen.

Next, the effect of the writing instrument A will be described.
Since the outer peripheral surface 1a at the substantially center in the axial direction of the grip 2 has a raised portion 2a and an inclined curved surface portion 2b that smoothly continues in the axial direction, when the user grasps it, as shown in FIG. The fingertip portions of the index finger F2 and the middle finger F3 from the thumb F1 of the finger not only contact the surface of the grip 2, but a substantially U-shaped inter-finger skin surface F4 extending from the thumb F1 to the index finger F2 includes a raised portion 2a and It fits with the surface shape of the inclined curved surface portion 2b, and each can be contacted without any gap.

  On the other hand, when the user grips the writing instrument A ′ having the same outer diameter throughout the entire length of the grip 2 ′ as disclosed in JP-A-2-141295, as shown in FIG. 5. When the fingertip portions of the index finger F2 and the middle finger F3 from the thumb F1 come into contact with the grip portion 2f ′ on the surface of the grip 2 ′, the substantially U-shaped inter-finger skin surface F4 extending from the thumb F1 to the index finger F2 and the grip 2 A gap S is formed between the surface and the gripping force of the finger, which fluctuates greatly during writing, is concentrated only on the fingertip portion.

  As a result, the writing instrument A according to the present invention increases the contact area between the skin surface of the finger and the surface of the grip 2, greatly reduces the shake of the entire barrel 1, and integrates the finger and the grip 2. When gripping force (gripping force) is transmitted to the grip 2, not only the fingertip portions of the thumb F1, the index finger F2, and the middle finger F4 but also the surface portions of the raised portion 2a and the inclined curved surface portion 2b are appropriately elastically deformed according to the shape of the fingers. In addition, the gripping force is evenly distributed to improve the fit with the fingers and prevent slippage in the axial direction due to sweat or the like.

  The shaft 2 of the grip 2 with respect to the shaft cylinder 1 is engaged with the axially and circumferentially-displacement protrusions 1b, 1c provided on the outer peripheral surface 1a of the shaft cylinder 1 and the inner peripheral surface 2c of the grip 2. Misalignment in the direction and circumferential direction is prevented.

  In particular, when the rear end 2e of the grip 2 is held by the locking band 5 so as not to move in the axial direction and the circumferential direction with respect to the shaft cylinder 1, not only the assembly and aesthetics are excellent, but also the forward position. This is preferable because it is excellent in the function of preventing misalignment.

Note that the overall shape of the grip 2 described above is not limited to the shape in the illustrated example, and if there is a raised portion 2a and an inclined curved surface portion 2b on the outer peripheral surface 1a in the approximate center in the axial direction, for example, the raised portion 2a and the inclined curved surface portion 2b. Alternatively, a plurality of protrusions and recesses may be formed in accordance with the shape of the finger in portions other than the portions where the raised portions 2a and the inclined curved surface portions 2b are disposed.
Further, the above-described misalignment-preventing protrusion is not limited to the annular protrusion 1b and the vertical protrusion 1c, but protrusions having other shapes may be added, or an arrangement other than the illustrated example may be employed.

  In the previous embodiment, the elastic ring 4 is disposed between the grip 2 and the front opening 3, and the rear end 2 e of the grip 2 is axially and circumferentially connected to the shaft cylinder 1 by the locking band 5. However, the present invention is not limited to this, and the front end of the grip 2 can be brought into direct contact with the rear end surface of the front port 3 without the elastic ring 4 or the rear of the grip 2. The end 2d may be held immovably in the axial direction by a locking means other than the locking band 5.

Further, in the illustrated example, a case is shown in which the writing tip 7a of the refill 7 incorporated in the shaft cylinder 1 is always protruded from the tip 3 and is detachably covered with a cap 8. However, the present invention is not limited to this, and a ballpoint pen having a structure in which the writing tip portion 7a is made to appear and disappear by a knocking operation or a rotation operation, or other types such as a mechanical pencil or a sign pen may be used.
Furthermore, although the shaft cylinder 1 has an integral structure that cannot be separated, the present invention is not limited to this, and the shaft cylinder 1 may have an integral structure that can be separated by screwing and joining the front shaft and the rear shaft. good.

It is the front view partly notched which shows one Example of the writing instrument of this invention. It is a partially notched front view which reduces and shows a decomposition | disassembly state. FIG. 3 is a partially enlarged cross-sectional bottom view along (3)-(3) in FIG. 1. It is a partial perspective view which shows a writing state. It is a partial perspective view which shows an example of the writing state by the conventional writing instrument.

DESCRIPTION OF SYMBOLS 1 Shaft cylinder 1a Peripheral surface 1b Misalignment protrusion (annular protrusion) 1c Misalignment protrusion (vertical protrusion)
2 Grip 2a Raised portion 2b Inclined curved surface portion 2c Inner circumferential surface 2e Rear end portion 5 Locking band

Claims (6)

In a writing instrument comprising a shaft tube and an elastically deformable grip that is inserted into the tube shape so as to cover substantially the entire axial length of the shaft tube ,
The grip includes a raised portion formed over the entire circumference on the outer circumferential surface in the substantially axial direction , a front inclined curved surface portion that is smoothly and continuously reduced in diameter toward the front of the raised portion, and a height of the raised portion. A rear-side inclined curved surface portion that is continuously and smoothly reduced in diameter to the rear, a front-side cylindrical portion that is connected to a front end of the front-side inclined curved surface portion and extends forward, and the rear-side inclined curved surface A rear cylindrical part connected to the rear end of the part and extending backward,
The raised portion is formed on an inclined surface that slightly increases in diameter linearly as it goes forward, and connects the front inclined curved surface portion to the front end of the inclined surface and the rear end on the rear end of the inclined surface. By connecting the inclined curved part on the side, the diameter is expanded to a substantially trapezoidal longitudinal section,
The axial length of the front inclined curved surface portion, the raised portion and the rear inclined curved surface portion is longer than the axial length of the front cylindrical portion and the rear cylindrical portion combined. Is also set larger,
The front cylindrical portion and the rear cylindrical portion have substantially the same diameter, and the front cylindrical portion is formed shorter in the axial direction than the rear cylindrical portion. Writing instrument characterized by that. When the index finger and the middle fingertip part from the thumb of the finger are in contact with the grip surface when gripped by the user, the substantially U-shaped inter-finger skin surface from the user's thumb to the index finger is the surface of the grip. The writing instrument according to claim 1, wherein the writing instrument is fitted with no gap . On the outer peripheral surface of the shaft cylinder, a protrusion for preventing slippage is provided which engages with the inner peripheral surface of the grip so as to be immovable in the axial direction and the circumferential direction
The misalignment preventing projection includes a vertical projection extending in the axial direction of the shaft cylinder and an annular projection extending in the circumferential direction of the shaft cylinder. The writing instrument according to claim 1 or 2 , wherein a pair of protrusions are provided. 4. The writing instrument according to claim 3, wherein the grip is made of foam and the gap is about 5 mm or more . Wherein the foam is a foam of closed cell structure, the surface hardness of 15 to 30 degrees, an impact resilience of 15% or less, the apparent density using those 0.08~0.17g / cm ³ The writing instrument according to claim 4. By wrapping a locking band around the rear end portion of the grip, the grip rear end portion is compressed and deformed, and is locked so as to be immovable in the axial direction and the circumferential direction with respect to the axial tube.
A locking projection is provided on the inner periphery of the locking band, and the locking projection and a recess formed in the shaft tube are fitted in the radial direction of the shaft tube. The writing instrument according to any one of 1 to 5.

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