JP2011025524A - Multi-core writing utensil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-core writing utensil which can surely bring the pen tip into a protruding condition without the finger slipping from the operating portion when the operating portion is slid forward with the finger placed thereon. <P>SOLUTION: A plurality of writing bodies 6 are stored in a cylinder barrel 2 in a backward and forward movable manner. The operating portion 7 is connected to the rear ends of the respective writing bodies 6. The operating portion 7 is protruded outward in the radial direction from the window hole 41 of the cylinder barrel2. The pen tip 61 of the writing body 6 emerges out of the front end hole 31 of the cylinder barrel 2 by pressing forward the operating body 7 along with the window hole 41. The operating portion 71 of the operating body 7 consists of a first protruding portion 71a protruding outward in the radial direction from the window hole 41, and a second protruding portion 71b protruding outward in the radial direction from the outer surface of the first protruding portion 71a, and a third protruding portion 71c located behind the second protruding portion 71b and protruding outward in the radial direction from the outer surface of the first protruding portion 71a. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to a multi-core writing instrument.

In Patent Document 1, a plurality of core shafts having different writing colors are accommodated in the shaft cylinder, and operation portions provided on the respective core shafts are exposed to the outside from the shaft tube. In the writing instrument that is selected and used, the operation portion is provided with a convex portion or a concave portion, and the shape of the convex portion or the concave portion in the operation portion of each core shaft is different from each other. A writing instrument with a different feel of the operation unit is described.

In the multi-core writing instrument of the above-mentioned Patent Document 1, when the finger is placed on the operation part and the operation part is slid forward, the finger slides from the operation part to the pen tip protruding state, and the pen is surely moved. There is a possibility that it cannot be brought into a protruding state. Further, the multi-core writing instrument of Patent Document 1 may cause the finger to feel pain when sliding forward while pressing the operation unit strongly inward in the radial direction so that the finger does not slip on the operation unit. Moreover, since the multi-core writing instrument of the above-mentioned patent document 1 is different in shape of the operation unit and the contact between each operation unit and the finger is not constant, when sliding the operation unit forward, the operation unit and the finger Something may be unstable.

JP 2003-335093 A

The present invention solves the above-described conventional problems, and when a finger is placed on the operation unit and the operation unit is slid forward, the pen tip protrudes reliably without sliding the finger from the operation unit. It is intended to provide a multi-core writing instrument that can be used.
In the present invention, in the barrel, "front" refers to the front end hole side, "rear" refers to the opposite side, in the cursive, "front" refers to the pen tip side, "rear" Refers to the opposite side.

1st invention of this application accommodates the some writing body 6 in the axial cylinder 2 so that a movement in the front-back direction is possible, the operation body 7 is connected with the rear end of each said writing body 6, and each said writing body 6 and the operating body 7 are urged rearward by the elastic body 8, and a plurality of window holes 41 extending in the front-rear direction are provided in the side wall of the shaft cylinder 2 in the radial direction. The operating portion 71 of each operating body 7 is protruded outward, and one operating body 7 is slid forward along the window hole 41, so that the one operating body 7 is first projected. The operation body 7 of the other writing body 6 that was previously in contact with the operation body 7 of the other writing body 6 and the operation body 7 of the other writing body 6 that was previously in the pen tip protruding state and the inner wall of the shaft cylinder 2 are released. The cursive body connected to the operating body 7 that has been slid into the shaft 2 by immersing the nib 61 of the other cursive body 6 in the protruding state in the shaft cylinder 2 The pen tip 61 protrudes from the front end hole 31 of the shaft cylinder 2, and the operating portion 71 of the operating body 7 is protruded radially outward from the window hole 41 by a first protruding portion 71 a. A second projecting portion 71b projecting radially outward from the outer surface of the first projecting portion 71a, and a radially outward direction from the outer surface of the first projecting portion 71a, arranged rearward of the second projecting portion 71b. A maximum length A in the radial direction from the surface other than the operation portion 71 of the operation body 7 to the outer end portion in the radial direction of the operation portion 71. It is a requirement that it is set to be larger than the maximum radial length B from the surface other than the operation unit 71 to the back surface of the operation body 7.

In the multi-core writing instrument 1 according to the first aspect of the present invention, the operation portion 71 of the operation body 7 includes a first protrusion 71a that protrudes radially outward from the window hole 41, and a radial direction from the outer surface of the first protrusion 71a. The second projecting portion 71b projecting outward, and the third projecting portion 71c disposed rearward of the second projecting portion 71b and projecting radially outward from the outer surface of the first projecting portion 71a. The maximum radial length A from the surface of the body 7 other than the operation unit 71 to the radially outer end of the operation unit 71 is the diameter from the surface of the operation body 7 other than the operation unit 71 to the back surface of the operation body 7. By setting it to be larger than the maximum length B in the direction, the second protrusion 71b and the third protrusion 71c are moved radially outward from the window hole 41 until the transition from the pen tip immersion state to the pen tip protrusion state is completed. Can be made to protrude sufficiently toward the operation part 71. When slide operation, without pressing strongly radially inward the operating portion 71, without the fingers from slipping from the operation unit 71, can be reliably nib projected state.

According to a second invention of the present application, in the multi-core writing instrument 1 of the first invention, the radially outer end of the second projecting portion 71b and the radially outer end of the third projecting portion 71c are convex curved surfaces. It is a requirement that it is formed in a shape.

The multi-core writing instrument 1 according to the second aspect of the invention has the operation portion 71 by forming the radially outer end portion of the second projecting portion 71b and the radially outer end portion of the third projecting portion 71c into a convex curve shape. There is no risk of causing the finger to feel pain even if the user slides forward while pressing strongly inward in the radial direction.

According to a third invention of the present application, in the multi-core writing instrument 1 of the first or second invention, the second projecting portion 71b projects more forward than the first projecting portion 71a, and the third projecting portion 71c is the first. The second projecting portion 71b and the third projecting portion 71c of the operating body 7 at the rear end of the writing body 6 projecting rearward from the projecting portion 71a project from the window hole 41 radially outward. Is a requirement.

In the multi-core writing instrument 1 of the third invention, the second protrusion 71b protrudes forward of the first protrusion 71a, the third protrusion 71c protrudes rearward of the first protrusion 71a, and the pen tip The second projecting portion 71b and the third projecting portion 71c of the operating body 7 at the rear end of the writing body 6 in the projecting state project radially outward from the window hole 41, whereby the axial length of the window hole 41 is increased. Without considering this, the second protrusion 71b and the third protrusion 71c can be freely set large.

The multi-core writing instrument 1 of the fourth invention of the present application is the multi-core writing instrument 1 of the first, second or third invention, wherein the writing body 6 and the operating body 7 can be detached from the shaft cylinder 2 in a connected state; It is a requirement that it can be inserted into the shaft cylinder 2.

When the multi-core writing instrument 1 according to the fourth aspect of the invention is configured such that the writing body 6 and the operating body 7 can be detached from the shaft cylinder 2 and inserted into the shaft cylinder 2 in a connected state, the first, second, With the configuration of the third invention, it is easy to pick the operation unit 71 with a finger, and the writing body 6 and the operation body 7 can be easily replaced.

The multi-core writing instrument 1 of the fifth invention of the present application is the same as the multi-core writing instrument 1 of the first, second, third or fourth invention, wherein the shape of the operation portion 71 of each operation body 7 is the same. Is a requirement.

In the multi-core writing instrument 1 according to the fifth aspect of the present invention, since the shape of the operation portion 71 of each operation body 7 is the same, the contact between each operation portion 71 and the finger becomes constant, and any operation portion 71 is controlled. Even if the slide operation is performed, the pen tip can be reliably projected without sliding the finger from the operation unit 71.

According to the multi-core writing instrument of the present invention, when a finger is applied to the operation unit and the operation unit is slid forward, the pen tip protrudes reliably without the finger slipping from the operation unit.

It is a longitudinal cross-sectional view which shows the pen tip immersion state of embodiment of this invention. It is a longitudinal cross-sectional view which shows the pen tip protrusion state of FIG. It is a side view which shows the operation body and writing body in a mutually connected state of FIG. It is a side view which shows the opening state of the opening part of FIG.

1 to 4 show an embodiment of the present invention.

The multi-core writing instrument 1 according to the present embodiment includes a shaft cylinder 2 and a plurality of writing bodies 6 accommodated in the shaft cylinder 2 so as to be movable in the front-rear direction. An operation body 7 is fixed to the rear end of each of the writing bodies 6. Each of the writing body 6 and the operation body 7 is urged rearward by a resilient body 8 (specifically, a compression coil spring). In the present invention, the number of the writing bodies 6 that are movably accommodated in the shaft cylinder 2 may be two or more, and in addition to two, three, four, five, six, etc. It may be.

(Shaft tube)
The shaft cylinder 2 includes a front shaft 3 formed of a tapered cylindrical body, and a cylindrical rear shaft 4 attached to the rear end portion of the front shaft 3 by screwing or press-fitting. At the front end of the front shaft 3, a front end hole 31 through which the pen tip 61 of the writing body 6 can protrude is provided in the axial direction. The front shaft 3 and the rear shaft 4 are obtained by injection molding of a synthetic resin (for example, polycarbonate).

A plurality (specifically, two) elongated window holes 41 extending in the front-rear direction are provided in a radial direction in the rear side wall of the rear shaft 4. Further, an opening 42 is formed at the rear end of the rear shaft 4 so as to penetrate rearward in the axial direction and open radially outward. The opening 42 communicates with the window hole 41 at the rear end of the rear shaft 4 (that is, the rear end of the shaft cylinder 2), whereby the rear end of the window hole 41 is notched rearward and opened rearward. On the other hand, the front end of the window hole 41 is always closed.

Further, a locking wall portion 43 made of a rib extending in the front-rear direction is formed on the inner surface of the side wall between the window holes 41 of the rear shaft 4, and the pen tip 61 protrudes from the locking wall portion 43. The rear end of the operating body 7 of the cursive body 6 is locked.

A clip 45 is provided at the rear end portion of the outer surface of the side wall between the window holes 41 of the rear shaft 4. A hinge portion 46 is formed at the base of the clip 45.

(Cover)
At the rear end portion of the rear shaft 4, a lid portion 5 that can open and close the opening portion 42 is provided rotatably. The lid 5 includes a lid main body 51 that closes the opening 42, and two leg pieces 52 that are connected to the lid main body 51. The leg piece 52 of the lid portion 5 is rotatably connected to the rear shaft 4 by a hinge portion 46. The pivot shaft of the hinge portion 46 extends in the left-right direction of the hinge portion 46 when the hinge portion 46 is viewed from the front with the pen tip facing downward, whereby the lid portion 5 is rotatable in a substantially front-rear direction. It becomes.

An abutting wall portion 53 is formed on the front surface of the lid portion 5 (lid body 51). The rear end of each operation body 7 connected to the rear end of the writing body 6 in the pen tip immersion state is bumped to the contact wall portion 53.

(Engagement part, engaged part)
An engagement portion 54 is provided on the front surface of the lid portion 5 (lid body 51) (specifically, an engagement recess or an engagement hole portion is formed). An engaged portion 44 that can engage with the engaging portion 54 is provided at the rear end of the rear shaft 4 (specifically, an engaging convex portion protrudes). An inward projection is formed on the inner surface of the engagement portion 54 (engagement recess or engagement hole), while the outer surface of the engaged portion 44 (engagement projection) climbs over the inward projection. A lockable outward projection is formed.

The engaging portion 54 and the engaged portion 44 are in an engaged state with each other when the lid portion 5 closes the opening 42 (specifically, the inward projection and the outward projection are over and locked). When the operating body 7 and the contact wall portion 53 on the front surface of the lid 5 are brought into contact with each other by the rearward urging of the projectile body 8, the engaged state is not released and the lid 5 is not opened. That is, when the opening 42 is closed by the lid 5, the rear portion of the lid 5 is prevented by the engagement of the engaging portion 54 and the engaged portion 44.

(Cursive)
Each of the writing bodies 6 may be, for example, a refill provided with a known pen tip 61 such as a ballpoint pen refill, a mechanical pencil refill, a sign pen refill, a marking pen refill, or an input pen refill (stylus pen refill).

In the present embodiment, a ballpoint pen refill is employed (see FIG. 3). The ball-point pen refill includes a ball-point pen tip (pen tip 61), an ink storage tube 62 having the ball-point pen tip at the front end and containing ink therein, and a rear end of the ink storage tube 62 (that is, the ink storage tube 62). The operation body 7 is fixed to the rear end opening).

(Operation body)
As shown in FIG. 3, each operation body 7 of the ballpoint pen refill includes an operation portion 71 formed at the rear end portion and protruding from the window hole 41 of the shaft tube 2 to the outside of the shaft tube 2, and opposite to the operation portion 71. A front projection 72 provided on the side, a rear projection 73 provided behind the front projection 72 on the opposite side of the operation unit 71, and a rear end opening formed at the front end and the ink containing tube 62. A fitting portion 74 to be fitted and a flange portion 75 formed behind the fitting portion 74 are provided. The rear end of the projectile 8 is locked to the front surface of the collar portion 75.

The operating portion 71 includes a first protruding portion 71a protruding radially outward from the outer surface of the side wall of the shaft cylinder 2 through the window hole 41, and a first protruding portion protruding radially outward from the outer surface of the first protruding portion 71a. 2 projecting portions 71b and a third projecting portion 71c projecting radially outward from the outer surface of the first projecting portion 71a. The third protrusion 71c is disposed behind the second protrusion 71b. A radially outer end portion of the second projecting portion 71b and a radially outer end portion of the third projecting portion 71c are formed in a convex curved surface shape. The first projecting portion 71a, the second projecting portion 71b, and the third projecting portion 71c are plate-shaped, and the second projecting portion 71b and the third projecting portion 71c have the same shape (a front-rear symmetrical shape). . The first projecting portion 71a may have a semicircular shape, and the second projecting portion 71b and the third projecting portion 71c may have substantially the same disc shape.

In the present embodiment, the maximum radial length A from the surface other than the operation unit 71 of the operation body 7 to the operation unit 71 is the second protrusion 71b or the second length from the surface of the operation body 7 other than the operation unit 71. It becomes the maximum length in the radial direction up to the radially outer end of the three projecting portions 71c. In the present embodiment, the maximum radial length B from the surface other than the operation portion 71 of the operation body 7 to the back surface of the operation body 7 is the front protrusion 72 or the length from the surface other than the operation portion 71 of the operation body 7. This is the maximum radial length up to the back surface of the rear protrusion 73.

The second projecting portion 71b projects forward of the first projecting portion 71a, the third projecting portion 71c projects rearward of the first projecting portion 71a, and the operating body at the rear end of the writing body 6 in the pen tip projecting state. Seven second projecting portions 71 b and third projecting portions 71 c project radially outward from the window hole 41.

In the multi-core writing instrument 1 in which the refill shown in FIG. 3 is accommodated in the shaft cylinder 2, when the pen point 61 of the writing body 6 is in an immersive state, the rear end portion of the operating body 7 attached to the writing body 6 is a lid. The contact wall 53 formed on the front surface of the portion 5 is bumped. On the other hand, when the pen point 61 of the writing body 6 is in a protruding state, the rear end portion of the operating body 7 attached to the writing body 6 is locked to a locking wall portion 43 formed on the inner wall of the shaft cylinder 2. The Further, in the multi-core writing instrument 1 in which the refill shown in FIG. 3 is accommodated in the shaft cylinder 2, the front protrusion 72 of the operating body 7 connected to the rear end of the writing body 6 in the pen tip immersion state is the operating body. When the operation portion 71 of 7 is moved forward, it comes into contact with the rear side protruding portion 73 of the operation body 7 connected to the rear end of the other writing body 6 in the pen tip protruding state, and the other writing The locked state between the operating body 7 connected to the rear end of the body 6 and the locking wall 43 is released, and the pen tip protruding state of the other writing body 6 is released.

In the present embodiment, the first projecting portion 71 a, the second projecting portion 71 b, and the third projecting portion 71 c of the operating body 7 at the rear end of the writing body 6 in the pen tip projecting state are connected to the shaft cylinder through the window hole 41. The first projecting portion 71a, the second projecting portion 71b, and the third projecting portion 71c of the operating body 7 at the rear end of the writing body 6 that is radially outwardly projected from the outer surface of the pen tip are in a window. It protrudes radially outward from the outer surface of the shaft tube 2 through the hole 41. As a result, the operation unit 71 is sufficiently protruded outside the shaft tube 2, and when the finger is applied to the operation unit 71 and the operation unit 71 is slid forward, the pen tip is surely not slipped from the operation unit 71. It can be in a protruding state.

(Projection support part)
A cylindrical projectile support 9 is fixed to the inner wall of the shaft cylinder 2 (that is, the inner wall of the rear shaft 4). The projectile support 9 has a plurality of (specifically, two) inner holes 91 through which the writing body 6 is inserted, extending in the axial direction. A projectile 8 is disposed between the rear surface of the projectile support 9 and the front surface of the collar 75 of each operating body 7. While the cursive body 6 is loosely inserted into each of the bullet bodies 8, the front end of each bullet body 8 is locked by the rear surface of the bullet body support portion 9, and the rear end of each bullet body 8. Is locked to the front surface of the collar portion 75 of the operating body 7. The bullet body 8 biases the writing body 6 and the operation body 7 backward.

(Invitation of the nib)
A description will be given of the operation of the pen tip 61 in the present embodiment.
When the operating portion 71 of one operating body 7 is moved forward along the window hole 41 against the rearward bias of the projectile 8, the front protrusion 72 of the operating body 7 moved forward is The rear projecting portion 73 of the operating body 7 of the other writing body 6 in the projecting state is lifted outward in the radial direction. As a result, the locking state between the locking wall portion 43 of the inner wall of the shaft tube 2 and the operating body 7 is released, and the other writing body 6 is moved rearward by the rear urging of the projectile body 8, so that the other writing body. The pen tip 61 of 6 is immersed in the shaft cylinder 2, and the rear end of the operating body 7 of the other writing body 6 is brought into contact with and abutted against the contact wall 53 of the front surface of the lid 5. Simultaneously with the immersion of the pen tip 61 of the other writing body 6, the pen tip 61 of the writing body 6 connected to the operating body 7 moved forward is protruded to the outside from the front end hole 31 of the shaft cylinder 2. At the same time, the rear end of the operating body 7 moved forward is locked to the locking wall portion 43 of the inner wall of the shaft tube 2, and the pen tip protruding state is maintained.

(Replacement of cursive and operating body 7)
The replacement of the writing body 6 and the operating body 7 in the present embodiment will be described (see FIG. 4).
When replacing the writing body 6, the lid 5 closes the opening 42 at the rear end of the shaft tube 2, and pushes the operation end on the opposite side of the hinge portion 46 of the lid 5 backward to engage. The engagement between the portion 54 and the engaged portion 44 is released, the lid portion 5 is rotated rearward, and the opening 42 at the rear end of the shaft tube 2 is opened. When the opening 42 is opened, each operation body 7 is protruded from the opening 42 to the outside by the rear urging of the projectile 8. With the opening 42 at the rear end of the shaft cylinder 2 opened, the operating body 7 is taken out so that the writing body 6 connected to the operating body 7 is connected to the inside of the shaft cylinder 2 through the opening 42. Then, a new writing body 6 and a new operating body 7 that are connected to each other are inserted into the shaft cylinder 2 through the opening 42. Then, each operating body 7 is brought into contact with the contact wall 53 of the lid 5, and the lid 5 is rotated forward while pressing each operating body 7 forward. The opening portion 42 is closed by engaging the engaged portion 44. Thereby, the exchange work of the writing body 6 and the operation body 7 is completed. In the present embodiment, the writing body and the operation body 7 are exchanged through the opening 42, but other than this, the exchange may be performed through the window hole 41.

(Operation of this embodiment)
In the multi-core writing instrument 1 of the present embodiment, the operating portion 71 of the operating body 7 includes a first protruding portion 71a protruding radially outward from the window hole 41, and a radially outer side from the outer surface of the first protruding portion 71a. A second projecting portion 71b projecting outward, and a third projecting portion 71c disposed rearward of the second projecting portion 71b and projecting radially outward from the outer surface of the first projecting portion 71a. The radial maximum length A from the surface other than the operation unit 71 of the operation unit 7 to the outer end portion of the operation unit 71 in the radial direction is the radial direction from the surface of the operation unit 7 other than the operation unit 71 to the back surface of the operation unit 7. Is set to be larger than the maximum length B of the second protrusion 71b and the third protrusion 71c from the window hole 41 radially outward until the transition from the pen tip immersion state to the pen tip protruding state is completed. Can be made to protrude sufficiently toward the operation part 71. When slide operation, without pressing strongly radially inward the operating portion 71, without the fingers from slipping from the operation unit 71, can be reliably nib projected state.

In the multi-core writing instrument 1 of the present embodiment, the outer end portion in the radial direction of the second projecting portion 71b and the outer end portion in the radial direction of the third projecting portion 71c are formed in a convex curved surface, so that the operation portion 71 is provided. Even if the slide operation is performed forward while pressing strongly inward in the radial direction, there is no possibility that the finger will feel pain.

In the multi-core writing instrument 1 of the present embodiment, the second protrusion 71b protrudes forward of the first protrusion 71a, the third protrusion 71c protrudes rearward of the first protrusion 71a, and the pen tip protrudes. Since the second projecting portion 71b and the third projecting portion 71c of the operating body 7 at the rear end of the writing body 6 project radially outward from the window hole 41, the axial length of the window hole 41 is taken into consideration. Without doing, the 2nd protrusion part 71b and the 3rd protrusion part 71c can be freely set large.

In the multi-core writing instrument 1 of the present embodiment, when the writing body 6 and the operating body 7 are configured to be detachable from the shaft tube 2 in a connected state and insertable into the shaft tube 2, the second protrusion 71 b and the third Since the protruding portion 71c sufficiently protrudes radially outward from the window hole 41, the operation portion 71 can be easily picked with a finger, and the writing body 6 and the operation body 7 can be easily replaced.

In the multi-core writing instrument 1 according to the present embodiment, since the shape of the operation unit 71 of each operation body 7 is the same, the contact between each operation unit 71 and the finger becomes constant, and any operation unit 71 is slid. Even if operated, the pen tip protrudes reliably without the finger slipping from the operation unit 71.

DESCRIPTION OF SYMBOLS 1 Multi-core writing instrument 2 Shaft cylinder 3 Front shaft 31 Front end hole 4 Rear shaft 41 Window hole 42 Opening part 43 Locking wall part 44 Engaged part 45 Clip 46 Hinge part 5 Lid part 51 Lid body 52 Leg piece 53 Contact wall Part 54 engaging part 6 writing body 61 pen tip 62 ink containing tube 7 operating body 71 operating part 71a first projecting part 71b second projecting part 71c third projecting part 72 front projecting part 73 rear projecting part 74 fitting part 75 Part 8 Projection body 9 Projection body support part 91 Inner hole A Maximum length in the radial direction from the surface other than the operation part of the operation body to the outer end part in the radial direction of the operation part B Surface other than the operation part of the operation body Maximum radial length from the back of the control body

Claims (5)

A plurality of writing bodies are accommodated in the shaft cylinder so as to be movable in the front-rear direction, and operating bodies are connected to the rear ends of the writing bodies, and the writing bodies and the operating bodies are urged rearward by a resilient body. A plurality of window holes extending in the front-rear direction on the side wall of the shaft cylinder in a radial direction, and projecting the operation portions of the respective operation bodies radially outward from the respective window holes to perform one operation By sliding the body forward along the window hole, one of the operating bodies is brought into contact with the operating body of the other writing body that was previously in the pen tip protruding state, and the pen tip is in the protruding state first. The operation of releasing the locking state between the operation body of the other cursive body and the inner wall of the shaft cylinder, immersing the pen tip of the other cursive body that was in the protruding state first into the shaft cylinder, and sliding the operation forward A multi-core writing instrument in which a nib of a cursive body connected to the body is projected from the front end hole of the shaft cylinder,
The operating portion of the operating body includes a first protruding portion that protrudes radially outward from the window hole, a second protruding portion that protrudes radially outward from an outer surface of the first protruding portion, and the second protruding portion. And a third protruding portion that is arranged rearward and protrudes radially outward from the outer surface of the first protruding portion, from the surface other than the operating portion of the operating body to the radially outer end portion of the operating portion. The multi-core writing instrument, wherein a maximum length in a radial direction is set to be larger than a maximum length in a radial direction from a surface other than the operation portion of the operation body to a back surface of the operation body. The multi-core writing instrument according to claim 1, wherein a radially outer end portion of the second projecting portion and a radially outer end portion of the third projecting portion are formed in a convex curved surface shape. The second projecting portion projects forward from the first projecting portion, the third projecting portion projects rearward from the first projecting portion, and the second projecting portion of the operating body at the rear end of the writing body in the pen tip projecting state. The multi-core writing instrument according to claim 1 or 2, wherein the first protrusion and the third protrusion protrude outward in the radial direction from the window hole. The multi-core writing instrument according to claim 1, 2 or 3, wherein the writing body and the operating body are configured to be detachable from the shaft cylinder in a connected state and insertable into the shaft cylinder. The multi-core writing instrument according to any one of claims 1 to 4, wherein the shape of the operation portion of each operation body is the same.

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