JP7260969B2 - writing instrument - Google Patents

Description

The present invention relates to writing instruments. More specifically, the present invention relates to a writing instrument in which a mounting hole opening axially rearward is provided in the rear end portion of a cylindrical body such as a barrel or a cap of the writing instrument, and a friction body is inserted into the mounting hole.

Patent Document 1 discloses a friction member for erasing handwriting with thermochromic ink, in which the cross section exposed at the rear end of the friction member has a triangular, quadrangular, hexagonal, or other polygonal shape. A thermochromic writing instrument is described which is characterized by:

Further, in Patent Document 2, a mounting hole that opens upward in the axial direction is provided in the upper end portion of a barrel of a writing instrument or a cylindrical body such as a cap, and a soft member is attached by inserting the soft member into the mounting hole. The structure is characterized in that an inward projection is formed on the inner peripheral surface of the mounting hole, an outward projection is formed on the outer peripheral surface of the soft member, and the outward projection rides over the inward projection from above to below. A flexible member mounting structure is described.

JP 2016-144933 A JP 2007-144991 A

In the technique disclosed in Patent Document 1, it is necessary to rotate the barrel while visually recognizing the direction of the friction body before the friction operation, and it is not possible to shift to the friction operation quickly. In particular, if the barrel is provided with protrusions such as clips or anti-rolling protrusions, the user may be restricted in gripping method or gripping position. Therefore, even if the cross-sectional shape of the friction member (corresponding to the friction body of the present invention) is polygonal, it may be difficult for the user to use the portion of the friction member intended for rubbing.

Further, in the technique disclosed in Patent Document 2, the outer peripheral surface of the front end portion of the small diameter portion of the soft member (corresponding to the friction body of the present invention) (that is, the connecting portion between the small diameter portion of the soft member and the shoulder portion of the large diameter portion (outer peripheral surface of ) is formed with an inclined surface (i.e. conical surface) base whose outer diameter gradually increases toward the top, and when the soft member is inserted into the mounting hole, the inclined surface-shaped base , the user may not be able to freely rotate the soft member to the intended position due to pressure contact with the opening edge of the mounting hole. Therefore, even if the soft member has a polygonal cross-sectional shape, it may be difficult for the user to rub the portion of the soft member intended by the user.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems, and to provide a writing instrument that can quickly start a frictional operation using a portion of the frictional body intended by the user. .

In the present invention, "rear" refers to the friction body side of the entire writing instrument, and "front" refers to the side opposite to the friction body side. In addition, in the present invention, the "pen retracted state" refers to a state in which the pen tip is retracted into the barrel, and the "pen tip protruding state" refers to a state in which the pen tip protrudes from the front end hole of the barrel. Say.

The present invention is a writing instrument in which a mounting hole opening axially rearward is provided in the rear end of a cylindrical body such as a barrel or a cap of the writing instrument, and a friction body made of an elastic material is inserted into the mounting hole. The writing instrument has an inward projection formed on the inner peripheral surface of the mounting hole, an outward projection formed on the outer peripheral surface of the friction body, and the outward projection and the inward projection are engaged in the front-rear direction. The friction body has a large-diameter portion that protrudes axially rearward from the rear end of the tubular body and is inserted into the mounting hole so as to be rotatable about an axis. A writing instrument characterized by having a non-circular surface.

According to the present invention, the writing instrument has an inward projection formed on the inner peripheral surface of the mounting hole, an outward projection formed on the outer peripheral surface of the friction body, and the outward projection and the inward projection are engaged in the front-rear direction. The friction body has a large-diameter portion that protrudes axially rearward from the rear end of the cylindrical body, and is inserted into the mounting hole so as to be rotatable about an axis. Since the outer surface has a non-circular cross-sectional shape, the barrel may be provided with projections such as clips or anti-rolling projections, and the user may be restricted in the manner or position of gripping. Using the part of the friction body intended by the user, the friction operation can be started quickly.

According to the writing instrument of the present invention, it is possible to quickly start the frictional operation using the portion of the frictional body intended by the user.

1 is a vertical cross-sectional view of a writing instrument according to a first embodiment of the present invention; FIG. FIG. 2 is an enlarged vertical cross-sectional view of a main portion of FIG. 1; FIG. 2 is an enlarged vertical cross-sectional view of a main portion of FIG. 1; FIG. 2 is an enlarged vertical cross-sectional view of a main part at the time of friction in FIG. 1; FIG. 5(a) is an enlarged front view of the writing instrument (friction body) according to the first embodiment of the present invention. FIG. 5(b) is an enlarged side view of the writing instrument (friction body) according to the first embodiment of the present invention. FIG. 5(c) is a cross-sectional view taken along line AA of FIG. 5(a). FIG. 5(d) is a cross-sectional view taken along line BB of FIG. 5(a). 1 is an enlarged perspective view of a writing implement (frictional body) according to a first embodiment; FIG. FIG. 7(a) is an enlarged front view of a writing implement (friction body) according to a second embodiment of the present invention. FIG. 7(b) is an enlarged side view of the writing implement (friction body) in the second embodiment of the present invention. FIG. 7(c) is a sectional view taken along line CC of FIG. 7(a). It is an expansion perspective view of the writing implement (friction body) in 2nd Embodiment. FIG. 9(a) is an enlarged front view of a writing implement (friction body) according to a third embodiment of the present invention. FIG. 9(b) is an enlarged side view of a writing instrument (friction body) according to a third embodiment of the present invention. FIG. 9(c) is a cross-sectional view taken along line DD of FIG. 9(a). FIG. 9(d) is a cross-sectional view along line EE of FIG. 9(a). It is an expansion perspective view of the writing implement (friction body) in 3rd Embodiment. FIG. 11(a) is an enlarged front view of a writing instrument (friction body) according to a fourth embodiment of the present invention. FIG. 11(b) is an enlarged side view of a writing implement (friction body) according to a fourth embodiment of the present invention. FIG. 11(c) is a cross-sectional view taken along line FF of FIG. 11(a). FIG. 11(d) is a cross-sectional view taken along line GG of FIG. 11(a). It is an expansion perspective view of the writing instrument (friction body) in 4th Embodiment.

Four embodiments of the present invention will be described below with reference to the drawings.

<First embodiment>
1 to 6 show a first embodiment of the present invention.
The writing instrument 1 of this embodiment comprises a cylindrical body 2, a writing body 3 accommodated in the cylindrical body 2, and a pen point 31 of the writing body 3 which is retractable through a front end hole 21 of the cylindrical body 2. and a mechanism.

Cursive body The cursive body 3 includes a pen tip 31, an ink storage tube 32 in which the pen tip 31 is press-fitted and fixed to the front end opening, a thermochromic ink 33 filled in the ink storage tube 32, A follower 34 (for example, high-viscosity fluid) is filled in the trailing end of the thermochromic ink 33 and advances as the thermochromic ink 33 is consumed.

The pen tip 31 may, for example, consist of only a metal ball-point pen tip that rotatably holds a ball at its front end, or may consist of a synthetic resin pen tip holder that holds the rear outer surface of the ball-point pen tip. may be In addition, a tail plug having a ventilation hole is attached to the rear end opening of the ink storage tube 32 so that the ink storage tube 32 can communicate with the outside. Inside the pen tip 31 is accommodated a spring that pushes forward the ball at the front end. The spring is a compression coil spring having a rod portion at the front end thereof, and the front end of the rod portion is in contact with the rear surface of the ball. When not writing, the forward bias of the spring brings the ball into close contact with the inner surface of the inward front edge of the front end of the ballpoint pen tip, preventing ink from leaking from the front end of the nib 31 and evaporating ink.

Cylindrical body The cylindrical body 2 includes a tapered cylindrical front shaft 2a, a cylindrical intermediate shaft 2b connected to the rear end of the front shaft 2a, and a cylindrical body connected to the rear end of the intermediate shaft 2b. and a rear shaft 2c. A slide hole 22 extending in the axial direction is formed in the side wall of the cylindrical body 2 (for example, the side wall of the intermediate shaft 2b and the side wall of the rear shaft 2c). A mounting hole 23 is provided axially through the rear end of the cylindrical body 2 (that is, the rear end of the rear shaft 2c). A friction body 7 made of an elastic material is press-fitted into the mounting hole 23 . The friction body 7 is fixed to the outer surface of the rear end of the rear shaft 2c (cylindrical body 2) without interlocking with the axial movement of the operation portion 4. As shown in FIG. The friction body 7 is provided independently of the operating portion 4 . Further, the cylindrical body of the present invention may be a cylindrical body such as a cap of a writing instrument.

Inward Protrusion An annular inward protrusion 24 is integrally formed on the inner peripheral surface of the mounting hole 23 . The inward protrusion 24 has a guide portion 24a formed of an inclined surface (that is, a conical surface) whose inner diameter gradually decreases toward the front. In addition, the inward projection 24 has a front end surface formed of a surface perpendicular to the axis in front of the guide portion 24a. A minimum inner diameter portion 24b having an acute angle is formed between the guide portion 24a and the front end face.

- Retractable Mechanism The retractable mechanism is a side slide type retractable mechanism using a rotating cam mechanism. The retraction mechanism includes a cam portion formed on the inner surface of the intermediate shaft 2b, a rotating member 5 engaged with the cam portion and in contact with the rear end of the writing body 3, and a slide hole engaged with the rotating member 5. It is composed of an operating portion 4 projecting radially outward from 22, and an elastic body 6 (for example, a compression coil spring) that is accommodated in the cylindrical body 2 and biases the writing body 3 backward. The retraction mechanism of the present embodiment is of a double-knock type in which the operation unit 4 is slid forward for both the pen tip protrusion operation and the pen tip retraction operation. The rotating member 5 is obtained by a molding of synthetic resin (for example, polyacetal resin).

The cam portion includes a plurality of serrated cam teeth projecting forward and a plurality of axially extending cam grooves formed between the cam teeth. The rotating member 5 has a plurality of (for example, four) ridges extending in the axial direction on its outer surface, and the ridges are engaged with the cam teeth of the cam portion and the cam grooves of the cam portion. At the front end of the shaft portion 43 of the operating portion 4, cam teeth that engage with the rear ends of the projections of the rotary member 5 are formed integrally or by attachment of a separate member.

Operation Part The operation part 4 includes an operation base 41 projecting radially outward from a slide hole 22 extending in the axial direction of the side wall of the cylindrical body 2 . Further, the operation portion 4 includes a shaft portion 43 which is connected to the operation base portion 41 and accommodated in the cylinder 2 so as to be axially movable, and a clip portion 44 which is connected to the front side of the operation base portion 41. and The clip portion 44 can clip clothing such as a pocket. The operation part 4 is obtained by a molding of synthetic resin (for example, polycarbonate resin). A ball portion 42 protrudes from the rear surface (inner surface) of the clip portion 44 . The operation base portion 41 and the shaft portion 43, the operation base portion 41 and the clip portion 44, and the clip portion 44 and the ball portion 42 are each integrally formed by one member or formed by assembling two pieces. be.

The operation base 41 is axially movable along the slide hole 22 . The pen tip 31 of the writing body 3 is configured to be retractable from the front end hole 21 of the cylindrical body 2 by pushing the operation base 41 forward.

・When the operation base 41 of the operation unit 4 is slid forward against the backward bias of the elastic body 6 from the retracted state of the pen tip, the cam tooth of the shaft 43 of the operation unit 4 rotates the rotating member. 5 is pushed forward, and as the ridge of the rotary member 5 moves forward along the cam groove, the rotary member 5 pushes the rear end of the writing body 3 forward, and the pen tip 31 moves forward. It protrudes outside through the hole 21 . At this time, the contact between the cam teeth of the shaft portion 43 and the ridges of the rotating member 5 rotates the rotating member 5 by a constant angle with respect to the cam portion. As a result, the ridges of the rotating member 5 are engaged with the cam teeth of the cam portion, and the protruding state of the pen tip is maintained.

When the operation base portion 41 of the operation portion 4 is slid forward from the protruding state of the pen tip, the shaft portion 43 of the operation portion 4 pushes the rotary member 5 forward, and the cam teeth of the shaft portion 43 and the projection of the rotary member 5 are pushed forward. The contact with the ridge rotates the rotating member 5 by a constant angle with respect to the cam portion. As a result, the engagement between the projection and the cam tooth of the cam portion is released, and the projection moves rearward along the cam groove of the cam portion due to the backward biasing force of the elastic body 6 . As the rotary member 5 moves backward, the writing body 3 moves backward, and the pen tip is retracted.

Friction Body The friction body 7 is composed of a large-diameter portion 72 and a small-diameter portion 74 integrally connected to the front of the large-diameter portion 72, and is integrally formed of an elastic material. In the present embodiment, the friction body 7 employs a friction discoloration member that rubs the surface of the thermochromic handwriting to thermally discolor the handwriting.

The friction body 7 has outward protrusions 75 formed on its outer peripheral surface, and the outward protrusions 75 and the inward protrusions 24 are locked in the front-rear direction. The friction body 7 has a large-diameter portion 72 projecting axially rearward from the rear end of the cylinder 2, and is inserted into the mounting hole 23 so as to be rotatable about the axis. The outer surface of 72 has a cross-sectional non-circular shape. As a result, even if the cylindrical body 2 is provided with projections such as clips or anti-rolling projections, and the user may be restricted in gripping method or gripping position, the portion of the friction body 7 intended by the user can be easily controlled. can be used to quickly initiate a friction operation. In other words, if the friction body 7 is not rotatably inserted, projections such as clips or anti-roll projections will prevent proper gripping when the user attempts to rub against the intended location of the friction body 7. Inability to initiate friction operations quickly.

FIG. 5 is an enlarged view of the writing instrument 1 (friction body 7) according to the first embodiment of the invention, and FIG. 6 is a perspective view of FIG. As shown in FIGS. 5 and 6, when the friction body 7 is attached to the cylinder 2 (rear axle 2c), the large-diameter portion 72 exposed from the cylinder 2 has a substantially rectangular cross-sectional shape (see FIG. 5). (c)). Specifically, in cross section, the apex of the rectangle is rounded and arcuate, and the radius of curvature of the arc is larger at the front end of the large diameter portion 72 of the friction body 7 . As a result, the friction body 7 of the first embodiment of the present invention has a substantially rectangular cross-section, and when rubbing is performed on the short side of the substantially rectangular cross-section, a narrow range can be rubbed intensively. If the long side of the rectangular shape is rubbed, a wide area can be quickly rubbed, and the rubbing operation intended by the user becomes possible. In addition, the cross-sectional shape is not limited to a substantially rectangular shape, and may be an ellipse, a quadrangle, a hexagon, or other polygons.

The friction body 7 preferably has a small-diameter portion 74 integrally connected to the front from the large-diameter portion 72 and inserted into the mounting hole 23, and the outer surface of the small-diameter portion 74 has a circular cross section. have a shape. As a result, the friction body 7 can be stably mounted in the mounting hole 23, the friction body 7 can be easily rotated, and the friction operation can be quickly started using the part of the friction body 7 intended by the user. can be done. However, even if an injection-molded gate or the like is provided on the outer surface of the small-diameter portion 74, the above configuration is satisfied and the above effects are not hindered.

The friction body 7 preferably has a base portion 77 formed on the outer peripheral surface of the rear end portion of the small diameter portion 74 so that the base portion 77 of the small diameter portion 74 and the inner peripheral surface of the opening edge of the mounting hole 23 do not contact each other when there is no friction. is. As a result, the insertion resistance when inserting the friction body 7 is reduced, and the assembling efficiency is improved. In addition, when the friction body 7 is inserted into the mounting hole 23, the friction body 7 can be rotated more easily, and the friction operation can be quickly started using the part of the friction body 7 intended by the user. can do.

Moreover, it preferably has a contact portion 79 between the base portion 77 of the small diameter portion 74 and the inner peripheral surface of the opening edge of the mounting hole 23 when the paper surface 8 is rubbed. As a result, resistance is generated between the base portion 77 of the small-diameter portion 74 and the inner peripheral surface of the opening edge of the mounting hole 23, and the friction body 7 does not unexpectedly rotate about its axis during friction. Friction operation can be performed by using a portion of the friction body 7 intended by the user.

More preferably, a knob portion 78 is formed on the outer peripheral surface of the large-diameter portion 72 of the friction body 7 when the friction body 7 is rotated. Thereby, the friction body 7 can be rotated to the part of the friction body 7 intended by the user. Specifically, the knob portion 78 may be a width across flats portion such as a hexagonal or octagonal shape that can be spanned, or a form having a non-circular cross section such as a knurled portion. In addition, the knob portion 78 has an anti-slip effect. In the first embodiment, the large-diameter portion 72 is provided with a pair of chamfered portions, and the friction body 7 can be rotated more easily by holding the chamfered portions between fingers. However, if the large-diameter portion 72 itself of the friction body 7 has a shape that makes it easy to pinch and rotate with fingers, the large-diameter portion 72 itself functions as the knob portion 78 .

Further, preferably, the cylindrical body 2 with the friction body 7 inserted therein is detachable from the writing instrument 1 . As a result, when the friction body 7 is worn out, it can be easily replaced with a new friction body 7. - 特許庁Also, the user can select and replace the desired shape of the friction body 7 for use. The cylindrical body 2 in which the detachable friction body 7 is inserted is attached to the writing instrument 1 by detachable screwing or fitting.

In the present embodiment, the elastic material constituting the friction body 7 is preferably an elastic synthetic resin (rubber, elastomer), such as silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin. (styrene-ethylene-butylene-styrene copolymer), fluororesin, chloroprene resin, nitrile resin, polyester resin, ethylene propylene diene rubber (EPDM), and the like. The synthetic resin having elasticity that constitutes the friction body 7 is a low-wear elastic material that produces almost no wear scum (eraser shavings) when rubbed, compared to a high-wear elastic material (such as an eraser). It is preferable to consist of

Large-diameter portion The rear surface of the large-diameter portion 72 has a convex curved shape. A shoulder portion 73 is formed at the front end of the large-diameter portion 72 so as to contact the opening end of the mounting hole 23 (specifically, the rear end of the rear axle 2c). The maximum outer diameter of the large diameter portion 72 is set larger than the inner diameter of the mounting hole 23 and smaller than the outer diameter of the rear end of the rear axle 2c.

Small-Diameter Portion An annular outward protrusion 75 is integrally formed on the outer peripheral surface of the front end portion of the small-diameter portion 74 . The outward protrusion 75 has a guide portion 75a formed of an inclined surface (that is, a conical surface) whose outer diameter gradually increases toward the rear. The outward projection 75 has a rear end surface that is perpendicular to the axis. A sharp corner is formed between the guide portion 75a and the rear end surface. The corner portion becomes the maximum outer diameter portion 75 b of the outward projection 75 . That is, the outward protrusion 75 has a guide portion 75a formed of an inclined surface whose outer diameter gradually increases toward the rear, and a maximum outer diameter portion 75b formed rearward of the guide portion 75a.

The maximum outer diameter of the outward projection 75 is set larger than the minimum inner diameter of the inward projection 24 and smaller than the inner diameter b of the mounting hole 23 behind the inward projection 24 . In the present embodiment, the maximum outer diameter of the outward projection 75 (that is, the outer diameter of the maximum outer diameter portion 75b) is set to 4.9 mm, and the minimum inner diameter of the inward projection 24 (that is, the inner diameter of the minimum inner diameter portion 24b) is It is set at 4.1 mm. A difference between the maximum outer diameter of the outward projection 75 and the minimum inner diameter of the inward projection 24 is preferably in the range of 0.5 mm to 2 mm (preferably 0.5 mm to 1 mm). As a result, it is possible to reliably prevent the friction body 7 from coming off, and it is possible to smoothly get over the outward projection 75 and the inward projection 24 .

An axially extending inner hole 71 is formed inside the friction body 7 . A front end of the inner hole 71 opens forward in the axial direction. The rear end of the inner hole 71 is positioned inside the large diameter portion 72 . Due to the inner hole 71 , the friction body 7 is formed in a bottomed cylindrical shape with a closed rear end and an open front end. In the present embodiment, since the inner hole 71 is formed at least radially inward of the outward projection 75 , when the outward projection 75 rides over the inward projection 24 , the radially inward elasticity of the outward projection 75 is reduced. Easy to transform.
The outer diameter a of the intermediate portion of the annular space (that is, the portion between the outward projection 75 and the shoulder portion 73) of the small diameter portion 74 is set to be smaller than the inner diameter b of the rearward portion of the mounting hole 23 relative to the inward projection 24. be. As a result, when the outward projection 75 and the inward projection 24 contact the outward projection 75 just before the outward projection 75 overcomes the inward projection 24 , the outer peripheral surface of the small diameter portion 74 behind the outward projection 75 and the rearward of the inward projection 24 . An annular space 76 is formed between the mounting hole 23 and the inner peripheral surface thereof. As shown in FIG. 2, when the outward projection 75 and the inward projection 24 are strongly pressed just before the outward projection 75 overcomes the inward projection 24, the small-diameter portion 74 behind the outward projection 75 moves radially outward. Even if it swells due to elastic deformation, since the annular space 76 is formed, the outer peripheral surface of the small-diameter portion 74 behind the outward protrusion 75 is not strongly pressed against the inner peripheral surface of the mounting hole 23, and the friction body 7 is not inserted. There is no risk of resistance to time. As a result, the outward projection 75 and the inward projection 24 can be smoothly overcome. Specifically, the outer diameter a is set to 4.9 mm, and the inner diameter b is set to 5.6 mm.

Axial clearance As shown in FIG. 3, the axial length A from the shoulder portion 73 of the friction body 7 to the rear end of the outward projection 75 (that is, the maximum outer diameter portion 75b) is equal to the rear end of the rear axle 2c. to the front end of the inward projection 24 of the mounting hole 23 (that is, the minimum inner diameter portion 24b) (see FIG. 3). Thereby, when the outward projection 75 climbs over the inward projection 24, the outward projection 75 can surely get over the inward projection 24 even if the outward projection 75 and the inward projection 24 do not slide well. As shown in FIG. 3, when the friction body 7 has been completely inserted into the mounting hole 23, the rear end of the outward projection 75 (that is, the maximum outer diameter portion 75b) is aligned with the front end of the inward projection 24 (that is, the minimum inner diameter portion 24b). ), and an axial gap C is formed between the front end of the inward projection 24 and the rear end of the outward projection 75 . Specifically, the axial clearance C is effectively in the range of 0.05 mm to 1.0 mm (preferably 0.1 mm to 0.5 mm). Due to the size of the axial clearance C, there is no large axial rattling when the friction body 7 is in use, and moreover, the inward protrusion 24 and the outward protrusion 75 can be reliably pushed over when the friction body 7 is inserted. . Specifically, in this embodiment, the axial length A is set to 8 mm, and the axial length B is set to 7.9 mm.

Then, as shown in FIG. 3, an axial gap C is formed between the rear end of the outward projection 75 and the front end of the inward projection 24 in a state where the outward projection 75 and the inward projection 24 have finished riding over each other. be. As a result, even if the outward projections 75 and the inward projections 24 do not slide well, the outward projections 75 and the inward projections 24 can be reliably overcome without applying a lubricant or the like. In addition, in a state in which the outward projection 75 and the inward projection 24 have finished getting over, the inward projection 24 is pressed against the outer peripheral surface of the small-diameter portion 74 behind the outward projection 75 . As a result, rattling in the axial and radial directions of the small-diameter portion 74 can be prevented. In addition, the rear end of the rear shaft 2 c is pressed against the shoulder portion 73 in a state where the outward projection 75 and the inward projection 24 have finished getting over. As a result, it is possible to prevent the large-diameter portion 72 from entering the mounting hole 23 and to prevent the large-diameter portion 72 from rattling in the radial direction.

According to the present invention, the writing instrument 1 has the inward protrusions 24 formed on the inner peripheral surface of the mounting hole 23, the outward protrusions 75 formed on the outer peripheral surface of the friction body 7, and the outward protrusions 75 and the inward protrusions 24. The friction body 7 has a large-diameter portion 72 projecting axially rearward from the rear end of the cylindrical body 2 and is inserted into the mounting hole 23 so as to be rotatable about its axis. The outer surface of the large diameter portion 72 has a non-circular cross section.

As a result, even if the cylindrical body 2 is provided with projections such as clips or anti-rolling projections, and the user may be restricted in gripping method or gripping position, the portion of the friction body 7 intended by the user can be easily controlled. can be used to quickly initiate a friction operation.

<Second embodiment>
7 and 8 show a second embodiment of the invention. This is a modification of the first embodiment, and the difference from the first embodiment is the shape of the large-diameter portion 72 of the friction body 7 . Since other configurations and effects are the same as those of the first embodiment, description thereof will be omitted.

FIG. 7 is an enlarged view of the writing instrument 1 (friction body 7) according to the second embodiment of the invention, and FIG. 8 is a perspective view of FIG. As shown in FIGS. 7 and 8, when the friction body 7 is attached to the cylinder 2 (rear axle 2c), the cross-sectional shape of the large-diameter portion 72 exposed from the cylinder 2 is substantially rectangular (see FIG. 7). (c)), and the difference between the long sides and the short sides is larger than that of the rectangular cross section of the first embodiment. That is, the cross section is formed in a longer and narrower rectangular shape than in the first embodiment. Specifically, in cross section, the apex of the rectangle is rounded and arcuate, and the radius of curvature of the arc is larger at the front end of the large diameter portion 72 of the friction body 7 . Accordingly, the friction body 7 of the second embodiment of the present invention has a substantially rectangular cross section, and when rubbing is performed on the short side of the substantially rectangular cross section, a narrow range can be rubbed intensively. If the long side of the rectangular shape is rubbed, a wide area can be quickly rubbed, and the rubbing operation intended by the user becomes possible.

In addition, since the friction body 7 of the second embodiment is formed in a rectangular shape with a longer and narrower cross section, the large diameter portion 72 itself of the friction body 7 can be easily rotated by pinching it with fingers. The portion 72 itself fulfills the function of the knob portion 78 .

<Third Embodiment>
9 and 10 show a third embodiment of the invention. This is a modification of the first embodiment, and the difference from the first embodiment is the shape of the large-diameter portion 72 of the friction body 7 . Since other configurations and effects are the same as those of the first embodiment, description thereof will be omitted.

FIG. 9 is an enlarged view of the writing instrument 1 (friction body 7) according to the third embodiment of the invention, and FIG. 10 is a perspective view of FIG. As shown in FIGS. 9 and 10, when the friction body 7 is attached to the cylinder 2 (rear shaft 2c), the large-diameter portion 72 exposed from the cylinder 2 has a substantially triangular cross-sectional shape (see FIG. 9). (c)). Specifically, in cross section, the vertices of the triangle are rounded and arcuate, and the radius of curvature of the arc is larger at the front end of the large diameter portion 72 of the friction body 7 . In cross section, the sides of the triangle are slightly rounded and arcuate, and the radius of curvature of the arc is smaller at the front end of the large diameter portion 72 of the friction body 7 . As a result, the friction body 7 of the third embodiment of the present invention has a substantially triangular cross section, and when rubbed at the vertex of the substantially triangular cross section, rubbing can be performed intensively in a narrow range. Friction on the sides of the shape enables rapid rubbing over a wide area, enabling the user to perform the rubbing operation intended by the user.

Further, as shown in FIG. 9(c), the friction body 7 of the third embodiment is formed with a knob portion 78 having a hexagonal cross section at the front portion of the large diameter portion 72 of the friction body 7. As shown in FIG. Thereby, the friction body 7 can be rotated more easily.

<Fourth Embodiment>
11 and 12 show a fourth embodiment of the invention. This is a modification of the first embodiment, and the difference from the first embodiment is the shape of the large-diameter portion 72 of the friction body 7 . Since other configurations and effects are the same as those of the first embodiment, description thereof will be omitted.

FIG. 11 is an enlarged view of the writing instrument 1 (friction body 7) according to the third embodiment of the invention, and FIG. 12 is a perspective view of FIG. 11 and 12, when the friction body 7 is attached to the cylinder 2 (rear shaft 2c), the cross-sectional shape of the large-diameter portion 72 exposed from the cylinder 2 is substantially triangular (Fig. 11). (c)). Specifically, in cross section, the vertices of the triangle are rounded and arcuate, and the radius of curvature of the arc is larger at the front end of the large diameter portion 72 of the friction body 7 . As a result, in cross section, the sides of the triangle are rounded and arcuate, and the radius of curvature of the arc is smaller than that of the third embodiment. As a result, the friction body 7 of the fourth embodiment of the present invention has a substantially triangular cross section, and when rubbed at the vertex of the substantially triangular cross section, rubbing can be performed intensively in a narrow range. Friction on the sides of the shape enables rapid rubbing over a wide area, enabling the user to perform the rubbing operation intended by the user.

Further, the friction body 7 of the fourth embodiment has a knurled portion formed in the front portion of the large-diameter portion 72 of the friction body 7 . Thereby, the friction body 7 can be rotated more easily.

1 writing instrument 2 cylindrical body 2a front shaft 2b intermediate shaft 2c rear shaft 21 front end hole 22 slide hole 23 mounting hole 24 inward projection 24a guide portion 24b minimum inner diameter portion 3 writing body 31 pen tip 32 ink storage tube 4 operation portion 41 operation base portion 42 Ball portion 43 Shaft portion 44 Clip portion 5 Rotating member 6 Resilient body 7 Friction body 71 Inner hole 72 Large diameter portion 73 Shoulder portion 74 Small diameter portion 75 Outward protrusion 75a Guide portion 75b Maximum outer diameter portion 76 Annular space
77 base
78 Knob portion 79 Contact portion 8 Page A Axial length from the front end of the large diameter portion to the rear end of the outward projection B Length in the axial direction from the rear end of the cylindrical body to the front end of the inward projection C Axial clearance a Outer diameter b of the intermediate part of the small diameter part Inner diameter of the part behind the inward projection of the mounting hole

Claims (5)

A writing instrument in which a mounting hole opening axially rearward is provided in the rear end portion of a cylindrical body of the writing instrument such as a barrel or a cap , and a friction body made of an elastic material is inserted into the mounting hole. forming an inward protrusion on the inner peripheral surface of the mounting hole, forming an outward protrusion on the outer peripheral surface of the friction body, and locking the outward protrusion and the inward protrusion in the front-rear direction;
The friction body has a large-diameter portion that protrudes axially rearward from the rear end of the cylindrical body, and is inserted into the mounting hole so as to be rotatable about an axis,
The rear end surface shape of the large-diameter portion is substantially rectangular, and opposite long sides of the substantially rectangular shape are parallel. is larger at the front end of the large-diameter portion than at the rear end of the large-diameter portion. The friction body is provided with a small-diameter portion integrally connected to the front from the large-diameter portion and inserted into the mounting hole, and the outer surface of the small-diameter portion has a circular cross-sectional shape. A writing instrument according to claim 1. 3. The writing instrument according to claim 2, wherein a base is formed on the outer peripheral surface of the rear end of the small diameter portion, and the base and the inner peripheral surface of the opening edge of the mounting hole are not in contact with each other when there is no friction. 4. The writing instrument according to claim 3, further comprising a contact portion between the base portion and the inner circumferential surface of the opening edge of the mounting hole when friction is applied. 5. The writing instrument according to any one of claims 1 to 4, wherein the large diameter portion has a knob formed on the outer peripheral surface thereof when the friction body is rotated.

Images