JP5495421B2 - Knock-type writing instrument - Google Patents

Description

  The present invention relates to a knock-type writing instrument that allows a writing tip to protrude and retract from a tip opening of a shaft tube by knocking a knock bar.

  In a conventional knock-type writing instrument, for example, a knock-type ballpoint pen, the ball-pen tip at the tip of the refill is fed out from the opening at the tip of the shaft cylinder by a rotary feeding mechanism arranged in the shaft cylinder by knocking the knock bar, and the knocking operation is repeated. Thus, the ball-point pen tip is retracted and accommodated in the shaft cylinder.

  In this type of knock-type ballpoint pen, a knock bar is disposed so as to protrude from the rear end portion of the shaft cylinder, and in the assembly, the knock bar is inserted from the opening of the shaft cylinder having a relatively large inner diameter on the pen tip side. Is inserted so that the tip end portion of the knock bar protrudes from the opening having a relatively small inner diameter at the rear end portion of the shaft tube.

  That is, the knock bar has a dimensional relationship such that the base end of the knock bar is caught by a step around the opening having a relatively small inner diameter at the rear end of the shaft cylinder. It is configured not to fall out.

  In the knock type ballpoint pen having the above-described configuration, in order to arrange a rotation feeding mechanism called a Kern knock mechanism near the rear end portion of the shaft cylinder, the shaft cylinder or the inner cylinder member inserted into the shaft cylinder is disposed. A rotor drive mechanism (also referred to as a cam member) formed in a sawtooth shape needs to be applied along. For this purpose, the outer diameter of the tip of the knock bar must be smaller than the inner diameter of the cam member.

  Therefore, when the rotary feeding mechanism is mounted on a writing instrument product having a slim design with a thin shaft cylinder, it is necessary to make the outer diameter of the tip of the knock bar even smaller. However, when the outer diameter of the tip of the knock bar is extremely small, an unbalanced sensation occurs between the outer diameter of the shaft tube and the outer diameter of the knock bar, which is not preferable on the tether.

  In order to avoid such a problem, a knock type ballpoint pen in which a large-diameter knock cover formed of a separate part is attached to the tip of the knock bar is disclosed in Patent Document 1 shown below. Similarly, Patent Document 2 discloses a knock-type ballpoint pen in which another part is fitted to a knock bar in order to make the knock portion look thicker.

JP 2008-998 A Japanese Patent Application Laid-Open No. 10-119481

  In the conventional knock-type writing instrument including the knock-type ballpoint pen disclosed in the above-mentioned prior art documents, in any case, in order to assemble by inserting a knock bar from the pen tip side of the shaft cylinder, Patent Documents 1 and 2 described above as a retrofit Assembling processes such as preparing another part as shown in Fig. 5 and fitting it to the tip of the knock bar are necessary.

  According to this, an increase in the number of parts causes an increase in assembly procedures, and an increase in cost due to investment in molds required for manufacturing resin parts.

  The present invention was made in order to solve the problems of the conventional knock type writing instrument described above, and enables the knock bar to be inserted and assembled from the rear end side of the shaft tube, and the knock It proposes an attachment mechanism that can prevent rods and the like from falling off the shaft tube, and further simplifies the assembly work when the knock rod is inserted into the rear end side of the shaft tube and assembled. An object of the present invention is to provide a knock type writing instrument that can be used.

The knock type writing instrument according to the present invention, which has been made to solve the above-mentioned problems, is rotated so that the writing body can be fed forward by knocking a knock bar arranged at the rear end of the shaft tube. A knock-type writing instrument provided with a feeding mechanism, wherein the knock rod slides in the shaft tube by a knock operation of the knock rod, and at least one convex member is protruded and formed on the outer peripheral surface thereof; On the inner peripheral surface of the shaft cylinder on which the knock bar slides or on the inner peripheral surface of the inner cylinder member disposed in the shaft cylinder, a projection is formed in a parallel state along the axial direction. The first and second cam members each formed with a slanted surface, and a connecting member that protrudes so as to connect the two at the rear end side of the pair of cam members. The locking cam The convex member of the knock bar reciprocates in the U-shaped space of the locking cam by the action of a return spring that pushes the knock bar backward, and the knock bar is moved into the shaft tube. The first and second cam members are held in the same length in the front-rear direction, the knock bar has the convex member formed on the outer peripheral surface on the front end side, and the rear end portion. A convex rib member is formed on the outer peripheral surface, and a distance between the convex member on the front end side and the rib member on the rear end side is a, and the front and rear sides of the first and second cam members are When the dimension in the length direction is b, it is characterized in that a relationship of a> b is set .

Further, the knock type writing instrument according to the present invention is a knock type provided with a rotation feeding mechanism so that the writing body can be fed forward by knocking a knock bar arranged at the rear end portion of the shaft tube. A writing instrument that slides in the shaft cylinder by a knocking operation of the knock bar and has an outer peripheral surface protruding with at least one convex member, and a shaft on which the knock bar slides On the inner peripheral surface of the cylinder, or on the inner peripheral surface of the inner cylinder member arranged in the shaft cylinder, it is formed to project in a parallel state along the axial direction, and a serrated inclined surface is formed at the front end portion thereof. A locking cam formed in a U-shape is formed by the first and second cam members and a connecting member formed so as to protrude from the rear end side of the pair of cam members. Knock stick backward Due to the action of the returning spring, the convex member in the knock bar reciprocates in the U-shaped space of the locking cam, and the knock bar is held in the shaft tube, and the front end of the knock bar A plurality of convex members are formed at equal intervals along the circumferential direction on the outer peripheral surface of the section side, and the inner peripheral surface of the shaft cylinder or the inner peripheral surface of the inner cylinder member disposed in the shaft cylinder The same number of U-shaped locking cams as the convex members are formed at equal intervals along the inner circumferential direction, and the width of the convex member formed on the knock bar is e. When the width of the longitudinal groove formed between the locking cams formed in a letter shape is d, a relationship of d> e is set, and the knock bar has a plurality of the outer peripheral surfaces on the front end side. Convex members are formed at equal intervals along the circumferential direction, and the convex shape is formed on the outer peripheral surface on the rear end side. The same number of convex rib members as the material are formed at equal intervals along the circumferential direction, and the convex members and rib members formed on the knock bar are equally spaced when viewed in the axial direction of the knock bar. It is characterized by being alternately arranged .

  Further, in the case of adopting a configuration in which the inner cylinder member is disposed in the shaft cylinder, a locking portion protrudes from a part of the outer peripheral surface of the inner cylinder member and is formed on the side wall of the shaft cylinder. A configuration in which the inner cylinder member is fixed in the shaft cylinder can be suitably employed by locking the locking portion in the window hole.

In this case, when the knock bar is inserted into the inner cylinder member from the rear end side of the shaft cylinder, it comes into contact with the side surface of the large-diameter portion formed on the knock bar and prevents the knock bar from falling off. It is desirable that a contact member is formed.

  According to the knock type writing instrument having the above-described configuration, the first and second cam members and the connecting member are used to form the U on the inner peripheral surface of the shaft tube or on the inner peripheral surface of the inner tube member disposed in the shaft tube. A locking cam formed in a letter shape is provided, and a convex member formed on the outer peripheral surface of the knock bar is configured to be accommodated in the U-shaped space of the locking cam. The knock bar can be securely attached to the rear end of the shaft tube.

  In addition, the plurality of convex members formed on the outer peripheral surface on the front end side of the knock bar and the plurality of rib members formed on the outer peripheral surface on the rear end side are viewed in the axial direction of the knock bar. In this case, since the rib members are alternately arranged at equal intervals, the rib members are inserted into the vertical groove portions between the locking cams that are formed to be U-shaped, and the operation of pulling out the knock bar is performed as it is. Thus, the convex member formed on the knock bar can be easily accommodated in the U-shaped space of the locking cam.

  According to the above-described configuration, the assembly operation of the knock bar portion in the knock type writing instrument can be easily and simplified, and a mechanism for preventing the knock bar from falling off the shaft cylinder is formed in the shaft cylinder. be able to. Therefore, as disclosed in the above-mentioned prior art documents, it is possible to eliminate the necessity of mounting other parts on the tip of the knock bar to achieve a balance in design, and the knock bar is connected to the rear end of the shaft cylinder. It can be easily attached from the side.

It is the front view and center sectional drawing of a knock type writing instrument concerning this invention. It is the elements on larger scale which show the preferable external form of a shaft cylinder. It is the elements on larger scale which show the other preferable external form of a shaft cylinder. It is sectional drawing which showed arrangement | positioning relations, such as a shaft cylinder, the inner cylinder member accommodated in the inside, and a knock bar. It is the perspective view, front view, and center sectional view which expanded and showed the inner cylinder member shown in FIG. It is the elements on larger scale of the inner cylinder member enclosed with the dashed line E in FIG. It is the perspective view and front view which expanded and showed the knock stick. It is a schematic diagram explaining the mounting | wearing order of the knock bar in a shaft cylinder. It is a schematic diagram explaining the mounting | wearing order of the knock stick in the axial cylinder following FIG.

  Hereinafter, a knock type writing instrument according to the present invention will be described based on an embodiment for a knock type ballpoint pen. FIG. 1A is an external view showing the entire ballpoint pen, and FIG. 1B is a sectional view of the ball pen as viewed in the direction of the arrow from the central axis shown in FIG.

  In the ballpoint pen according to this embodiment, the shaft cylinder 1 is made of a resin material that hardly swells, such as polypropylene or polycarbonate, or a metal material such as aluminum or duralumin, and has a slim design as a whole. In particular, when the shaft tube is formed of a metal material, the weight occupied by the shaft tube can be reduced by using the light metal described above, which is desirable in that it does not impose a burden on the hand even during long-time writing.

  A screwing member 2 having a thread laid on the inner periphery is fitted into the front end portion of the shaft tube 1, and a tip portion 3 is screwed into the screwing member 2 and is detachably attached.

  The shaft tube 1 has a straight portion S and a curved portion in which the center is slightly depressed along the axial direction as shown in FIG. A configuration in which C and C are alternately continued, or as shown in an enlarged view in FIG. 3, a curved portion C having a slightly depressed center is continuous.

  The curved portion C shown in FIGS. 2 and 3 is formed with a radius of curvature R = 0.3 mm to 0.5 mm of the curved portion C so as to fit a fingerprint of a general human finger. The axial distance D at each central portion is preferably 0.3 to 0.5 mm. According to the configuration of the shaft cylinder 1 described above, since a continuous depression is formed so as to be orthogonal to the axial direction to which the writing load is applied, even if a person with high writing pressure handles it, the sliding in the axial direction due to the writing load is prevented. It is difficult to occur and the gripping performance can be improved.

  The above-described shaft cylinder 1 can be formed by injection molding when the material is resin, and when the material is metal, it is formed by utilizing automatic lathe, lathe processing, sintering processing, or the like. can do.

  Returning to FIG. 1, a synthetic resin middle cylinder member 4 is fitted and attached to the rear end portion of the shaft cylinder 1, and an attachment portion 4 a formed on the side surface of the end portion of the middle cylinder member 4. The base end portion of the metal clip 5 is inserted and attached. A knock bar 6 is slidably mounted in the middle cylinder member 4 in the axial direction. In this embodiment, a metal decoration cover 7 is attached to the knock bar 6. .

  A ballpoint pen refill 8 as a cursive body is accommodated in the shaft cylinder 1, and the refill 8 is disposed between a stepped portion having a different diameter formed in a part of the refill and the lip portion 3. The returned spring 9 receives a biasing force rearward. The rear end portion of the refill 8 is in contact with the rotor 11 accommodated in the middle cylinder member 4.

  The rotor 11 moves forward with the refill 8 in response to the knocking operation of the knocking bar 6, and moves to the retracted position shown in FIG. 1 by the action of the return spring 9 in response to the knocking operation of the knocking bar 6 again. It is configured as follows. That is, a cam member is formed in the middle cylinder member 4 as will be described later, and a rotation feeding mechanism called a Kern knock mechanism is configured together with the rotor 11 in contact with the cam member.

  FIG. 4 shows the configuration of the middle cylinder member 4 and the rotor 11 accommodated in the rear end portion of the shaft cylinder 1, and FIGS. It is shown in a sectional view in a positional relationship shifted by degrees.

  As shown in FIG. 4, the middle cylinder member 4 is formed with a locking portion 4 b so as to protrude from the side surface of the middle cylinder member, and this locking portion 4 b is a side wall of the shaft tube 1. The inner cylinder member 4 is fixed in the shaft cylinder 1 by entering into the window hole 1 a formed in the upper part. That is, the middle cylinder member 4 is inserted into the shaft cylinder from the rear end portion of the shaft cylinder 1, so that the locking portion 4b is engaged in the window hole 1a of the shaft cylinder 1, thereby the middle cylinder. The member 4 is fitted so as not to drop off from the rear end portion of the shaft tube 1. The detailed configuration of the locking portion 4b will be described later with reference to FIG.

As shown in FIG. 5, the structure of the middle cylinder member 4 is formed with the contact member 4 c to the knock bar 6 on the opposite side in the circumferential direction from the position where the locking portion 4 b is arranged. . The contact member 4c acts so as to come into contact with a large-diameter portion 18 (described later) of the knock rod 6 inserted into the middle cylinder member 4 with a slight spring force.

  As will be described later, when the knock bar 6 is inserted into the middle cylinder member 4 from the rear end side of the shaft cylinder 1, the contact member 4c is in contact with the large-diameter portion of the knock bar 6 so that the knock bar 6 is in the middle. It fulfills the function of temporarily securing the cylinder member 4 so that it does not fall off. That is, when the knock bar 6 is mounted in the middle cylinder member 4 using a jig or the like (not shown), the knock bar 6 can be suitably used to temporarily fix the knock bar 6 in the middle cylinder member 4 for the time being. it can.

  As shown in FIG. 5 (C), a first cam member 13a and a second cam member 13b, each of which has a serrated inclined surface A formed at the front end thereof, are formed on the inner peripheral surface of the intermediate cylinder member 4. The locking cam 13 is formed in a U-shape by a connecting member 13c which is formed to protrude in parallel and protrudes so as to connect the two cam members at the rear end side of the pair of cam members. Yes.

  In this embodiment, the axial lengths of the first cam member 13a and the second cam member 13b are formed to be the same. The three locking cams 13 each formed in a U-shape are arranged at equal intervals in the circumferential direction in the middle cylinder member 4, and the space between the locking cams 13 is on the inner peripheral surface. It is made into the vertical groove part 14 dented relatively with respect to each locking cam 13 formed by protrusion.

  When the knock bar 6 is inserted and mounted from the rear end side of the shaft tube 1, the gap formed by the vertical groove portion 14 passes through a convex member (described later) formed at the tip of the knock bar 6, The locking cam 13 functions so as to be able to enter the U-shaped space.

  FIG. 6 is an enlarged view of the locking portion 4b of the inner cylinder member 4 surrounded by the chain line E in FIG. The locking portion 4b is formed so as to slightly protrude to the outside of the inner cylinder member 4 via the inclined surface S. As described above, the locking portion 4b is placed in the window hole 1a of the shaft cylinder 1 By engaging from the inside, the middle cylinder member 4 is held in the shaft cylinder 1.

  A protrusion P parallel to the axis is formed on the surface of the locking portion 4b so as to continue from the inclined surface S. This linearly formed protrusion P effectively prevents the locking portion 4b from being excessively worn when the locking portion 4b enters the window hole 1a formed in the side wall of the shaft tube 1. Thus, it is possible to prevent the locking portion 4b from being poorly inserted into the shaft tube 1.

7 (A) and 7 (B) show the structure of the knock bar 6 described above. The knock bar 6 is formed in a cylindrical shape from a synthetic resin, and has a convex shape on the peripheral surface of the tip. A shaped member 16 is formed along the axial direction. Three convex members 16 are formed at equal intervals in the circumferential direction, and are mounted so as to be slidable in the axial direction while entering the U-shaped space of the locking cam 13 as will be described later. Thus, the knock bar 6 acts to prevent the knock bar 6 from dropping from the rear end portion of the shaft tube 1.

  Further, an end surface of the front end portion of the knock bar 6 is formed with a mountain valley portion 17 in which a mountain valley is continuous in an annular shape, which is the same mountain valley formed on the end surface of the rotor 11 as shown in FIG. It abuts on the portion 11a and acts to slightly rotate the rotor 11 in one direction. On the other hand, on the peripheral side surface of the rotor 11, like the above-described cam member 13a, three cam members 11b having serrated inclined surfaces are formed at equal intervals in the circumferential direction.

  In the rotor 11, the serrated inclined surface provided on the cam member abuts on the inclined surface S of the first and second cam members 13a and 13b, so that the knock bar 6 is knocked. The rotor 11 is given a rotational motion. As a result, the cam surface on the rotor 11 side is in contact with the cam members 13a and 13b and set in the axial front position, and falls into the longitudinal groove portion 14 and is axially moved. The state of moving to the rear position is repeated.

  Accordingly, the ballpoint pen tip portion of the refill 8 urged rearward by the spring member 9 is in a writable state that is drawn out from the front end opening of the lip portion 3, and the ballpoint pen tip portion retreats to form a shaft cylinder. The state accommodated in is alternately selected. The above-described configuration is conventionally called a Kern knock mechanism.

  On the other hand, as shown in FIG. 7, a large-diameter portion 18 is formed in a hook shape near the rear end portion of the knock bar 6, and a rib member 19 that protrudes forward from the large-diameter portion 18. Are formed at intervals of 120 degrees. The convex rib members 19 and the convex members 16 described above are alternately arranged at equal intervals of 60 degrees when viewed in the axial direction of the knock bar 6.

  8 and 9 schematically show a procedure for mounting the knock bar 6 from the rear end side to the inner cylinder member 4 attached to the shaft cylinder 1 described above. 8 and 9, two of the cam members 13 formed at equal intervals in the inner cylinder member 4 are flattened and formed on the outer peripheral surface of the knock bar 6 at equal intervals. The convex member 16 and the convex rib member 19 are also shown in a state where an appropriate number is developed in a planar shape.

  When the knock rod 6 is mounted in the inner cylinder member 4, the convex member 16 formed on the outer periphery of the tip of the knock rod 6 may come into contact with the connecting member 13 c formed in the inner cylinder member 4. . In this case, by rotating the knock bar 6 slightly to the left and right, as shown in FIG. 8 (A), each convex member 16 is guided into the vertical groove portion 14 formed between the respective locking cams 13. be able to.

  That is, the width e of the convex member 16 formed on the knock bar 6 is slightly narrower than the width d of the vertical groove portion 14 formed between the locking cams 13 in the inner cylinder member 4.

  When the knock bar 6 is inserted into the inner cylinder member 4 in this state, the convex member 16 passes through the longitudinal groove portion 14 as shown in FIG. 8B, and the first and second cam members 13a, The front end of 13b is reached. At this time, the convex rib member 19 formed on the outer peripheral surface of the knock bar 6 contacts the connecting member 13c. This is because the convex members 16 and the rib members 19 are alternately arranged at equal intervals of 60 degrees when viewed in the axial direction of the knock bar 6 as described above.

  As shown in FIG. 8 (B), when the rib member 19 comes into contact with the connecting member 13c, the convex members 16 are formed from the front end portions of the first and second cam members 13a and 13b. Is located further forward. That is, the distance between the convex member 16 formed on the knock bar 6 and the convex rib member 19 is a, and the length dimension of the first and second cam members 13a and 13b is b. In this case, the relationship of a> b is set.

  Subsequently, the tip of the rib member 19 enters the above-described vertical groove portion 14 as shown in FIG. 8C by performing an operation of slightly rotating (rotating 60 degrees) while pushing the knock bar 6 lightly. . At this time, each convex member 16 is located between the first and second cam members 13a and 13b.

  In this state, as shown in FIG. 9D, by pulling back the knock bar 6 to the rear, each convex member 16 has a U-shaped space between the first and second cam members 13a and 13b. Get in. Thereby, each convex member 16 abuts on the connecting member 13c that connects the first and second cam members, so that the connecting member 13c serves as a stopper, and the knock bar 6 is prevented from falling off.

  By knocking the knock bar 6 in this state, as shown in FIG. 9 (E), each convex member 16 moves inside the U-shaped space between the first and second cam members 13a and 13b. Will move. That is, the convex member 16 formed on the knock bar 6 moves in the U-shaped space to guide the knock bar 6, and the knock bar 6 functions to perform a knock operation in the front-rear direction.

  And it accommodates in the shaft cylinder 1 by the rotation delivery mechanism (Kern knock mechanism) containing the above-mentioned rotor 11 located in the front end side of the knock bar 6, and the said locking cam 13 etc. which were formed in the middle cylinder member 4. The refill 8 can be moved back and forth, and the ball-point pen tip portion can be caused to appear and disappear from the front end opening of the tip portion every time the knock bar 6 is knocked.

  In addition, according to above-described embodiment, the hollow part g can be formed between the middle cylinder member 4 and the knock stick 6 as shown in FIG. Therefore, by accommodating the coil spring in the hollow portion g, it is possible to maintain the posture in which the knock bar 6 is always protruded to the rear position regardless of the protruding state of the ballpoint pen tip portion.

  In the embodiment described above, the middle cylinder member 4 in which the locking cam 13 or the like is formed is fitted in the rear end portion of the shaft cylinder 1, but this is not performed using the middle cylinder member 4. By forming the locking cam 13 and the like on the inner peripheral surface of the shaft tube 1, a writing instrument having the same configuration can be realized.

  In the above-described embodiment, the locking cam 13 formed on the intermediate cylinder member 4, the convex member 16 formed on the knock bar 6, and the rib member 19 are each formed in three. The number of can be set arbitrarily.

  Furthermore, the knocking writing instrument according to the present invention can be applied to a correction pen, a glue application pen, and the like in addition to the ballpoint pen as shown in the embodiment.

DESCRIPTION OF SYMBOLS 1 Shaft cylinder 1a Window hole 3 Tip part 4 Middle cylinder member 4b Locking part 4c Contact member 6 Knock stick 8 Ball-point pen refill (writing body)
DESCRIPTION OF SYMBOLS 9 Return spring 11 Rotor 13 Locking cam 13a 1st cam member 13b 2nd cam member 13c Connecting member 14 Longitudinal groove part 16 Convex member 17 Mountain valley part 18 Large diameter part 19 Rib member A Inclined surface P Protrusion

Claims (4)

A knock type writing instrument provided with a rotation feeding mechanism so that a writing body can be fed forward by knocking a knock bar arranged at a rear end portion of the shaft cylinder,
A knock bar that slides in the shaft cylinder by a knocking operation of the knock bar, and at least one convex member projects from the outer peripheral surface thereof;
On the inner peripheral surface of the shaft cylinder on which the knock bar slides or on the inner peripheral surface of the inner cylinder member disposed in the shaft cylinder, a projection is formed in a parallel state along the axial direction. The first and second cam members each formed with a slanted surface, and a connecting member that protrudes so as to connect the two at the rear end side of the pair of cam members. A locking cam is provided,
Due to the action of a return spring that pushes the knock bar backward, the convex member of the knock bar reciprocates in the U-shaped space of the locking cam, and the knock bar is held in the shaft cylinder ,
The first and second cam members have the same length in the front-rear direction, and the knock bar has the convex member formed on the outer peripheral surface on the front end side and the outer periphery on the rear end side. A convex rib member is formed on the surface, the distance between the convex member on the front end side and the rib member on the rear end side is a, and the longitudinal direction of the first and second cam members A knock-type writing instrument characterized in that the relation of a> b is set, where b is the dimension of . A knock type writing instrument provided with a rotation feeding mechanism so that a writing body can be fed forward by knocking a knock bar arranged at a rear end portion of the shaft cylinder,
A knock bar that slides in the shaft cylinder by a knocking operation of the knock bar, and at least one convex member projects from the outer peripheral surface thereof;
On the inner peripheral surface of the shaft cylinder on which the knock bar slides or on the inner peripheral surface of the inner cylinder member disposed in the shaft cylinder, a projection is formed in a parallel state along the axial direction. The first and second cam members each formed with a slanted surface, and a connecting member that protrudes so as to connect the two at the rear end side of the pair of cam members. A locking cam is provided,
Due to the action of a return spring that pushes the knock bar backward, the convex member of the knock bar reciprocates in the U-shaped space of the locking cam, and the knock bar is held in the shaft cylinder ,
A plurality of the convex members are formed at equal intervals along the circumferential direction on the outer peripheral surface on the front end side of the knock bar, and the inner cylinder disposed in the inner peripheral surface of the shaft cylinder or in the shaft cylinder On the inner peripheral surface of the member, the same number of U-shaped locking cams as the convex member are formed at equal intervals along the inner peripheral direction, and the width of the convex member formed on the knock bar Is set to a relationship of d> e, where d is the width of the longitudinal groove formed between the locking cams formed in a U shape.
The knock bar has a plurality of convex members formed on the outer peripheral surface on the front end side at equal intervals along the circumferential direction, and the same number of convex members on the outer peripheral surface on the rear end side as the convex members. The rib members are formed at equal intervals along the circumferential direction, and the convex members and rib members formed on the knock bar are alternately arranged at equal intervals when viewed in the axial direction of the knock bar . Knock-type writing instrument characterized by that. In the configuration in which the inner cylinder member is disposed in the shaft cylinder, a locking portion protrudes from a part of the outer peripheral surface of the inner cylinder member, and the engagement is in a window hole formed in a side wall of the shaft cylinder. The knock type writing instrument according to claim 1 or 2 , wherein the inner cylinder member is fixed in the shaft cylinder by locking the stopper. The inner cylinder member is a contact member that contacts the side surface of the large-diameter portion formed on the knock bar and prevents the knock bar from dropping off when the knock bar is inserted from the rear end side of the shaft cylinder. The knock type writing instrument according to claim 3 , wherein:

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