JP3392230B2 - Double writing instrument - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiple writing instrument in which the tips of a plurality of writing bodies can be alternately projected and retracted at the front end of the front shaft and an eraser can be retracted and retracted from the rear end of the rear shaft.

[0002]

2. Description of the Related Art Heretofore, as an example of a compound writing instrument, as shown in Japanese Utility Model Application Laid-Open No. 64-3491 by the same applicant, a sliding groove for guiding two writing instruments is provided on the leading shaft. The front end has a guide cylinder fixed to the guide cylinder and a cam slope contacting the sliding pieces attached to the two cursive bodies fitted to the guide cylinder. It is equipped with a cylindrical cam that is movable in the axial direction and is integrally rotated in the circumferential direction.By rotating the cap with respect to the tip shaft, the two cursive writing bodies are selectively moved at the tip end opening of the tip shaft. There are multiple writing instruments that can appear and disappear.
Further, as seen in Japanese Patent Application Laid-Open No. 3-79397, there is a circumferential cam slant surface which is displaced in the axial direction at the rear end edge of the sliding piece, and a cam engaging projection that abuts against the slanting cam slant surface is formed in the inner hole portion of the cap. There is a double-sided writing instrument. Also, the actual development Sho 58-265
No. 89 and Japanese Utility Model Application Laid-Open No. 58-26577, there are known those having an eraser or other writing instrument at the rear end portion of the barrel. Also, as a conventional example, a double-type writing instrument in which another article such as an eraser or other writing instrument is replaceably provided at the rear end portion of a shaft cylinder is known by the same applicant in Japanese Utility Model Publication No. 2-28077.

[0003]

By the way, in the conventional example, metal parts are used in many parts, the structure is complicated, and the number of parts is large. Further, the eraser feeding mechanism portion of the embodiment has a complicated structure, has a large number of parts, and cannot be provided at a low cost. Further, since the cap is long with respect to the front shaft, there is a problem that the front end and the rear end of the shaft cylinder are gripped for a rotating operation and the appearance is bad. The present application aims to solve the above problems.

[0004]

DISCLOSURE OF THE INVENTION The multiple writing instrument of the present invention devised to solve the above-mentioned problems is such that the tip of the resin-made tip shaft and the tip of the resin-made guide tube are in a non-rotatable and retaining state. The engaging parts to be fitted are respectively provided and both are fixed.
(As another measure, it is also possible to provide a threaded portion between them to join them together.) Also, a plurality of writing bodies in which sliding pieces are fixed to the rear ends of a plurality of guide grooves provided in the guide cylinder. Are fitted to each other via return springs so that they can be moved back and forth, and a cam slope that is displaced in the axial direction is provided at the front end in a circular shape, and a flange is projectingly provided on the inner hole surface, and the outer circumference of the guide cylinder rear end is The flange is fitted in the provided circumferential groove, and the resin-made cylindrical cam is rotatably and securely attached to the guide cylinder. Attach the center shaft with the guide cylinder covered and the rear shaft rotatably only to the rear end outer periphery of the center shaft with the cylindrical cam covered. This means that the shaft cannot be rotated. Further, the eraser feeding body includes a spiral cylinder having a spiral groove formed in the inner hole surface, and an inner cylinder having a slit portion which is inserted into the inner hole of the spiral cylinder and locked so as to be rotatable only relative to the spiral cylinder. A slider having a projection on its side and an eraser sandwiched in the inner cylinder is fitted into the inner cylinder, and the projection penetrates the slit portion and is engaged with the spiral groove. Further, a locking portion is formed on the rear end cylinder portion of the cylindrical cam, and a locking portion is formed on the cylinder portion at the front end of the inner cylinder of the eraser feeding body, so that the mutual locking portions elastically mesh with each other. Then, the two are fixed to each other, and the rear end portion of the eraser feeding body is appropriately projected from the rear end of the rear shaft. As described above, by rotating the rear shaft with respect to the center shaft, each sliding piece is alternately moved in the front-back direction so that the tip of each cursive body can be selectively retracted from the front end of the front shaft. As a result, the projection is guided to the slit portion and the slider slides in the axial direction, so that the eraser can appear and disappear from the rear end of the spiral cylinder. A step is formed on the eraser gripping piece of the slider, and a step is formed at the rear end of the inner hole of the spiral cylinder. Is projected from the rear end hole of the spiral cylinder, and the final state of the eraser can be confirmed. Further, at least one of them is a mechanical pencil writing body, and in a state in which the writing tip portion thereof projects from the tip end opening of the leading shaft, a cylindrical cam is provided so as to be axially shiftable with respect to the guide cylinder, and the rear end of the spiral cylinder is knocked. As a result, the axis of the cylindrical cam shifts and the core can be extended.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings. The compound writing instrument of the present invention includes a guide cylinder 1, a front shaft 2, a cylindrical cam 3, a middle shaft 4, a rear shaft 29, a pair of sliding pieces 5, 5 ', a mechanical pencil writing body 6, a writing body 7 such as a ballpoint pen, and an eraser feeding. The body 31 is the main component. First, as shown in FIG. 1, the guide tube 1 is made of resin and has an axially long guide groove 8 that is open to the side surface from approximately the center to the rear end, and the opposite side surface from the center to the rear. It has an axially long guide groove 8'opened to a position slightly forward of the end. In the front half of the guide tube 1, the holes 15a, 1 are formed in communication with the respective guide grooves 8, 8 '.
A tubular portion 9 having a partition portion 15 having 5b and having a front end opened is provided, and a flange portion 28 is formed on the outer peripheral portion near the rear end of the tubular portion 9, and further on the outer peripheral portion in front of the flange portion 28. A bulging engagement portion 12 is formed. In addition, an engaging groove 27 of the center shaft 4, which will be described later, is formed on the side surface slightly rearward of the rear end of the tubular portion 9.
A circumferentially bulging engagement portion 27 'is formed so as to be fitted with. Further, on the side surface of the rear end of the guide cylinder, there is a circumferential groove 16 in the circumferential direction.
Is provided. (It has the same structure as the tube portion of the guide tube disclosed in Japanese Utility Model Laid-Open No. 64-3491).

The front shaft 2 made of resin is tapered at the front, and has a front end opening having an inner step portion 24 at the front end of the inner hole.
Further, the rear end hole is provided with an engaging groove 11 which is engaged with an engaging portion 12 provided on the outer peripheral portion of the tubular portion 9 of the guide tube and which prevents the guide tube 1 from coming off and is prevented from rotating. . The tubular portion 9 and the front shaft 2 are detachably fixed with an appropriate force. (Same as the configuration of the front axle in Japanese Utility Model Publication No. 64-3491)

The cylindrical cam 3 is made of resin and has a cylindrical shape. The front end of the cylindrical cam 3 has a cam slope 13 which is circumferentially displaced forward and backward, and a notch 14 is formed at the foremost end of the cam slope 13. . or,
The side surface has a required number of ribs 3a to be fitted into guide grooves 29b of a rear shaft 29, which will be described later, and a fan-shaped flange portion 17 is provided on the inner surface behind the cam slope 13. Further, a cylindrical portion 3b is provided on the rear outer periphery and a tubular portion 39 is provided further rearward, and a rib 39a, a groove portion 39c and a rib 39b are formed on the outer periphery of the tubular portion 39 on the same line. Parts are provided at required places.

The resin rear shaft 29 has a shaft cylinder part with a slightly larger diameter, and a clip 30 is provided on the rear end side surface of the shaft cylinder part. In addition, a projection 29a is provided on the peripheral wall of the front inner hole, and a required number of guide grooves 29b are formed on the rear inner wall thereof.
On the other hand, a collar portion 4a is formed in the vicinity of the rear end of the resin-made center shaft 4, and a circumferential engagement groove 4b is further formed in the outer peripheral portion of the rear end. The protrusion 29a of the rear shaft 29 is elastically fitted into the engagement groove 4b, and is fixed to the center shaft 4 so as to be rotatable only. The rib 3a of the cylindrical cam 3 is fitted in the guide groove 29b so that the cylindrical cam 3 cannot rotate with respect to the rear shaft 29 and can move axially.

The sliding member 5 made of resin has a protrusion 19 on the outer surface, and the rear end face of the protrusion 19 has a central portion projecting and both sides thereof have substantially the same slope as the cam slope 13 of the cylindrical cam 3 described above. It has a cam slope. In addition, the flange portion 2 of the core pipe 20
1 is provided, and a hole is provided that is fitted to the core pipe 20 so that the core pipe 20 protrudes rearward for a long time. A tail plug 22 is fixed to the rear end hole of the core pipe 20 to close the rear end hole. Like the sliding piece 5, the sliding piece 5'has a projection 19 'and a cam slope, and a locking portion 23 for fixing the rear end of the writing body 7 such as a ballpoint pen is provided at the tip. The locking portion may be formed in a pipe shape and the rear end of the writing body may be fitted therein.

The mechanical pencil writing body 6 has a general chuck mechanism built-in, and is joined to the core pipe 20 via a joint 6a connected to the chuck mechanism at the rear end.
The sliding pipe 5 is fitted in contact with the flange portion 21 provided at the rear of the core pipe 20 protruding from the rear end of the sliding pipe 5.
The rear end hole is closed by the tail plug 22 as described above. The extension of the lead is the tip step 2 of the mechanical pencil writing body 6.
This is performed by sliding the chuck by the axial transition of the sliding piece 5 in conjunction with the cylindrical cam 3 in a state where 5 is in contact with the inner step portion 24 of the leading shaft 2.

The pencil pencil writing body 6 and the writing body 7 such as a ballpoint pen are connected to the respective sliding pieces 5 and 5'at their rear ends so as to be freely movable in the respective guide grooves 8 and 8'of the guide cylinder 1 described above. It is fitted and urged rearward by the return springs 26, 26 'interposed between the front end surfaces of the sliding pieces 5, 5'and the guide grooves 8, 8'of the guide cylinder 1 and the partition portion 15 on the front surface. It The cylindrical cam 3 is elastically fitted into the circumferential groove 16 of the guide cylinder 1 so as to be rotatable in the circumferential direction with respect to the guide cylinder 1 so as to be prevented from coming off and fixed. Normally, the circumferential groove 16 and the flange portion 17 are dimensioned so that the cylindrical cam 3 is prevented from rotating in a state in which each writing body projects from the tip end opening of the tip shaft.
Also, with the mechanical pencil writing material protruding, the collar 1
The circumferential groove position facing 7 is formed to be wide enough for the stroke required for feeding the core. Further, since the sliding pieces 5, 5'are urged rearward by the return springs 26, 26 ', the cam slopes of the protrusions 19, 19' are always kept in contact with the cam slope 13 of the cylindrical cam 3. ing.

The center shaft 4 covering the guide cylinder 1 is fitted with the cylindrical cam 3 and the rear shaft 29 is rotatably attached to the outer peripheral portion of the rear end of the center shaft 4, and the rear surface of the flange portion 28 of the guide cylinder 1 is covered. Is in contact with the front surface of the rear shaft 4, the projecting engagement portion 27 'is elastically fitted into the engagement groove 27 of the center shaft 4 to prevent the guide cylinder 1 from coming off the center shaft 4, In addition, a rotation stopper (not shown) is provided between them to be fixed. Further, the rib 3a of the cylindrical cam 3 is fitted into the guide groove 29b of the rear shaft 29, so that the rear shaft 29
On the other hand, the cylindrical cam 3 is non-rotatable but is configured so that its axis can move freely. Further, the front shaft 2 is fitted in the cylinder portion 9 of the guide cylinder 1, the rear end surface of the front shaft 2 is in contact with the front surface of the flange portion 28, and the engaging portion 12 of the cylinder portion 9 is connected to the front shaft 2. The front shaft 2 and the guide cylinder 1 are elastically fitted in the engagement groove 11 so that the front shaft 2 and the guide cylinder 1 are fixed in a rotation-stopping and slip-out preventing state. The front shaft 2 can be attached and detached with an appropriate force.

In this state, when the rear shaft 29 is rotated to one side with respect to the center shaft 4, the sliding piece 5 advances and the notch 14 at the foremost end of the cam slope 13 of the cylindrical cam 3 has one mechanical pencil writing body 6. The writing tip is locked to the projection 19 of the sliding piece 5 and the writing tip is projected from the tip end opening. When the rear shaft 29 is rotated to the other side with respect to the center shaft 4, the sliding piece 5 retracts, the writing tip of the mechanical pencil writing body 6 is retracted from the leading end of the leading axis, and the sliding piece 5'is moved forward. The writing tip portion of the writing body 7 such as the other ballpoint pen projects from the tip end opening of the tip shaft.

On the other hand, as shown in FIG. 3, the eraser feeding member has a spiral cylinder 32, an inner cylinder 36, a slider 44, and an eraser 50. The spiral cylinder 32 has a circumferential engagement groove 34 formed near the front end of the inner hole surface, and further has an axial spiral groove 33 formed behind it. Further, an inclined step portion 35 is circumferentially formed at the rear end of the inner hole, and a rear end hole through which the eraser 50 projects is penetrated.

The inner cylinder 36 has a step 38 on the front side, a circumferential locking projection 43 on the rear side close to the step 38, and a groove 37a and a projection 37c on the inner hole surface of the front cylinder of the step 38. , A tubular portion 37 in which a locking portion having a groove portion 37b in a line is formed at a required position.
And the slit portion 4 penetrating from the step 40 at the front end to the rear end on the side surface of the tubular portion 36 ′ integrally extending behind the tubular portion 37.
1 is formed at two opposite positions, and an inclined step portion 42 is formed at a substantially rear end of the cylindrical portion 36 '. Further, the entrance of the groove portion 37a is formed in a tapered shape.

The slider 44 has a tubular portion 44 "at its front end, and an eraser sandwiching piece 45 which is elastically deformable is provided at two opposing positions extending to the rear end of the tubular portion 44".
Further, a projection 46 is formed on each outer peripheral surface of the eraser holding piece 45 at a position where it can be engaged with the spiral groove 33, and a rear end portion 48 is formed having an inclined step portion 47 on the rear side. There is.
Further, a protrusion locking portion 49 is formed on the inner peripheral surface.

Next, the slider 44 is fitted in the tubular portion 36 'of the inner cylinder 36, and the eraser holding piece 45 is fitted in the slit portion 41. Further, the eraser 50 is fitted and locked by the locking portion 49 of the eraser holding piece 45 in a biting manner. From that state, the inner cylinder 36 is fitted into the inner hole of the spiral cylinder 32, and the protrusion 46 of the slider 44 is inserted into the spiral groove 33.
Is engaged with. Further, the locking projection 43 of the cylindrical portion 37 of the inner cylinder elastically engages with the locking groove 34 of the spiral cylinder, and the step 38 contacts the front end of the spiral cylinder 32. Further, at that time, the stepped portion 42 of the tubular portion 36 ′ comes into contact with the stepped portion 35 of the spiral tube 32 and the slit portion 41.
Deformation in the direction of diameter reduction is prevented. As described above, the spiral cylinder 32 is rotatable with respect to the inner cylinder 36 and cannot be pulled out, and the eraser feeding body 31 is configured. Further, by rotating the spiral cylinder 32 with respect to the inner cylinder 36, the protrusion 46 is guided by the slit portion 41 and the slider 44 slides in the axial direction.

Next, as shown in FIG. 2, the eraser feeding body 31 is inserted from the rear end hole of the rear shaft 29, and the cylindrical portion 3 of the inner cylinder is inserted.
A locking portion provided on the inner hole surface of 7 is fixed to each other by engaging with a locking portion provided on the rear end cylinder portion 39 of the cylindrical cam 3, and the rear end portion of the spiral cylinder 32 is rearward of the rear shaft 29. It is formed to appropriately protrude from the end hole. Further, the eraser feeding body 31 can be attached to and detached from the cylindrical cam 3. By the way, the groove portions 37a and 37b, which are the locking portions of the cylindrical portion 37, are fitted into the ribs 39a and 39b, which are the locking portions of the cylindrical portion 39 of the cylindrical cam, so that the mutual rotation is stopped, and the groove portion 39c is elastically attached to the protrusion 37c. Is inserted and is prevented from coming off. Further, when the tubular portion 37 and the tubular portion 39 are mounted, the arrowhead portion (not shown) at the tip of the rib 39b faces the taper portion at the entrance of the groove portion 37a, so that they can smoothly come into contact with each other without worrying about their mutual alignment. is there.

By the way, in the above-mentioned embodiment, the center shaft 4 and the guide cylinder 1 are formed separately, but if the guide portion for guiding the sliding piece is formed on the inner hole surface of the center shaft, the guide cylinder can be omitted. Is possible. 5 and 6, the protrusion 64 is formed on the peripheral surface of the cylindrical cam 60, and the protrusion 64 is formed along the guide groove 63 of the center shaft 61 in the peripheral groove 62 formed on the peripheral surface of the center shaft. An example is shown in which the cylindrical cam 60 is elastically fitted so as to prevent the cylindrical cam 60 from slipping out of the center shaft 61 and rotate within a certain range, and the above means can be incorporated into the above-described embodiment in design.

[0020]

When the rear shaft 29 is rotated to one side with respect to the center shaft 4,
As shown in FIG. 1, the notch 14 provided at the tip of the cam slope 13 of the cylindrical cam 3 engages with the sliding piece 5 of one mechanical pencil writing body 6 to project the writing tip from the tip end opening of the tip shaft. . At this time, the flange portion 17 of the cylindrical cam 3 is located in the wide portion of the circumferential groove 16. In this state, when the rear end of the spiral cylinder 32 is knocked and the cylindrical cam 3 is axially moved, the motion is transmitted to the sliding piece 5, the core pipe 20, and the mechanical pencil writing body 6, and the step portion 25 at the tip of the writing moves. From the state in which it is in contact with the inner step portion 24 of the tip shaft 2, the chuck further axially moves in association with the joint 6a and the core is extended. When the rear shaft 29 is rotated to the other side with respect to the center shaft 4, the mechanical pencil writing body 6 retreats, and instead, the writing tip portion of the writing body 7 such as a ballpoint pen projects from the tip tip opening.

Next, when the spiral cylinder 32 of the eraser feeding body 31 is rotated to one side with respect to the rear shaft 29, the slider 4 is moved.
Since the projection 46 of No. 4 moves along the slit portion 41 of the inner cylinder 36, the slider 44 is gradually retracted and the eraser 50 is fed out from the rear end hole of the spiral cylinder 32. When the spiral cylinder 32 is rotated to the other side, the slider 44 moves forward and the eraser 50 is retracted from the rear end hole of the spiral cylinder 32 together with the slider 44.

Further, as shown in FIG. 4, at the end of the eraser 50, the rear end portion of the eraser holding piece 45 is in contact with the step portion 35 of the spiral tube 32 at the rear end of the eraser when the slider 44 is retracted. Since 48 is projected, the end of the eraser 50 can be seen. Further, an engaging portion 49 with an eraser is provided on the inner surface of the protruding rear end portion 48, and an appropriate chamfer is provided on the edge of the rear end hole of the spiral cylinder 32 so that the rear end portion 48 can be easily deformed in the expanding direction. This makes it easier to take out the remaining eraser and install a new eraser.

[0023]

According to the present invention, as shown in the embodiment, the metal is replaced by the resin as compared with the conventional example, the number of parts is omitted, the structure is simplified, and the assembly is facilitated and the cost is reduced. . Further, since the cursive body is projected and retracted by rotating the rear shaft with respect to the center shaft, the rotating operation is easy. It is also possible to perform the rotating operation with one hand. Further, unlike the conventional example, the cap is not abnormally long with respect to the front shaft, so that a well-balanced appearance and a good appearance can be designed. Further, the present invention is extremely useful because the eraser feeding member is detachably accommodated at the rear end of the rear shaft so that the function is increased and the eraser feeding member can be used properly according to the purpose. That is, there is an advantage that application units other than the eraser can be freely attached. Further, there is an advantage that it is possible to know when the eraser is finished and that the eraser can be easily replaced.

[Brief description of drawings]

FIG. 1 is an overall vertical sectional view showing an embodiment of the present invention, which is partially non-sectional.

FIG. 2 is an enlarged cross-sectional view of the latter half of FIG.

FIG. 3 is a vertical sectional view of an eraser feeding body.

FIG. 4 is a cross-sectional view of essential parts showing a state when the eraser is finished.

FIG. 5 is a diagram illustrating another embodiment in which the cylindrical cam and the center shaft are locked.

6 is a cross-sectional view of the main parts in FIG.

[Explanation of symbols]

1 Guide tube 2 front axle 3 Cylindrical cam 3a rib 3b collar part 4 center axis 4a collar part 4b engagement groove 5 sliding pieces 5 "sliding piece 6 Mechanical pencil cursive 6a joint Cursive such as 7 ballpoint pens 8 guide grooves 8'guide groove 9 tube 10 knock spring 11 engaging groove 12 Engagement part 13 Cam slope 14 notches 15 partition 15a hole 15b hole 16 circumferential groove 17 Tsuba 18 through holes 19 protrusions 19 "protrusion 20 core pipe 21 Flange 22 tail plug 23 Locking part 24 Inner Step 25 steps 26 Return spring 26 'return spring 27 engagement groove 27 "engaging part 28 Flange 29 Rear axle 29a protrusion 29b Guide groove 30 clips 31 eraser feeding body 32 spiral tube 33 spiral groove 34 Locking groove 35 steps 36 Inner cylinder 36 'tube 37 Tube 37a groove 37b groove 37c protrusion 38 steps 39 tube 39a rib 39b rib 39c groove 40 steps 41 slit 42 steps 43 Locking protrusion 44 slider 44 'tube 45 Eraser clip 46 protrusions 47 steps 48 rear end 49 Locking part 50 eraser 60 cylindrical cam 61 center axis 62 circumferential groove 63 guide groove 64 protrusions

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B43K 24/14 B43K 24/18 B43K 29/02 B43L 19/00

Claims (3)

(57) [Claims] 1. Each of which is fixed to a resin-made front shaft and a center shaft, respectively.
The other party of the center pole of the guide portion in the guide tube or bore surface was formed was fixed in a removable state, the guide tube or the inner shaft of the guide
A plurality of guide grooves provided in the section, before each via a return spring a plurality of writing bodies and secured to the rear end of the sliding piece
The cylindrical cam is mounted so as to be movable rearward, and is fixed to the guide cylinder or the center shaft so as to be rotatable, and the front end edge of the cylindrical cam is provided with a circumferential cam slant surface that is displaced in the axial direction. By contacting the front edge of the slide and the rear edge of the sliding piece, each sliding piece is moved back and forth alternately by the rotation of the cylindrical cam with respect to the center axis, and the tip of each cursive body is selectively moved from the tip opening of the tip axis. In a double-sided writing instrument equipped with a front writing part capable of appearing in and out of, and a rear eraser feeding body capable of appearing in and out by being integrally connected to the rear end of a cylindrical cam and rotating the rear end part, The eraser feeding body 31 is provided with a spiral tube 32 having a spiral groove 33 formed in the inner hole surface, and a slit portion 41 inserted into the inner hole of the spiral tube 32 and locked to the spiral tube 32 so as to be rotatable only. And an inner cylinder 36 having a
The eraser 50 is sandwiched between the protrusions 46 on the side surface.
A slid that penetrates the rit portion 41 and is engaged with the spiral groove 33.
And a rear shaft 2 on the rear outer periphery of the center shaft 4.
9 is fixed so as to be rotatable only, the cylindrical cam 3 is prevented from rotating with respect to the rear shaft 29 in the inner hole portion of the rear shaft 29, and further, at the rear end of the cylindrical cam 3, the cylindrical portion 37 in front of the inner cylinder 36 is provided. The locking portion provided on the above is fixed to each other by locking the locking portion, and the projection 46 is guided by the slit portion 41 by the rotation of the spiral cylinder 32 with respect to the rear shaft 29, so that the slider 44 moves in the axial direction. A compound writing instrument configured such that the eraser 50 can slide in and out from the rear end of the spiral tube 32. 2. The inner cylinder 36 is provided with a step portion 40 that abuts on the front end of the spiral cylinder 32, and an engaging portion composed of a groove and a protrusion is provided on the inner hole surface of the front cylindrical portion 37 thereof. The slit portion 41 penetrating to the rear end is provided on the side surface of the tubular portion 36 ′ integrally extending to the rear of the 37, and the inclined step portion 42 is further formed at the substantially rear end of the tubular portion 36 ′. In addition, a step portion 35 which is adapted to prevent the slit portion 41 from being deformed in the diameter reducing direction is formed at the rear end of the inner hole of the spiral cylinder 32, and a step portion is provided behind the eraser holding piece 45 of the slider 44. The step portion 47 is formed so as to form the portion 47 and the step portion 47 comes into contact with the step portion 35 when the slider 44 is retracted. The multiple writing instrument according to claim 1, wherein the multiple writing instrument is configured so that it can be confirmed. 3. At least one of them is a mechanical pencil writing body, and a cylindrical cam 3 is provided so as to be able to move axially with respect to the guide cylinder 1 or the center shaft 4 in a state in which the writing tip portion projects from the tip end opening of the tip shaft. The invention is characterized in that the rear end of the rear shaft 29 is appropriately protruded and the rear end of the eraser 31 is appropriately knocked so that the cylindrical cam 3 can be axially moved to extend the core. The double-sided writing instrument described in 1.