JP3375567B2 - 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 materials can be alternately retracted and retracted at the tip of the tip of a tip.

[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 a conventional example of the present application, as seen in Japanese Utility Model Laid-Open No. 60-120889 by the same applicant, there is a double-sided writing instrument in which a crown protruding from a rear end of a cap is rotated so that an eraser appears and disappears. .

On the other hand, the conventionally known oil-based ballpoint pens have a high viscosity of several thousand mPa · S or more, so that the resistance when the balls rotate when the ink flows out from the pen tip. Has a drawback that the writing quality is bad because it is large. In addition, there is a problem that the amount of ink flowing out from the tip during writing is small, there is a battering phenomenon, there is uneven writing line, the handwriting density is low, and a high writing pressure is required.
As an improvement of this oil-based ballpoint pen, recently, an intermediate viscosity range (several mPa · S to several thousands mPa ·
A ballpoint pen for water-based ink called medium viscosity using the ink of S) has been developed. This is a ballpoint pen using a relatively low-viscosity water-based ink having a characteristic that viscosity is reduced by the rotation of the tip ball and ink smoothly flows out, so-called shear thinning viscosity. However, since this ink has a defect that the ink is easily dried, a cap for sealing the writing tip is usually required. Further, the outflow amount of ink increases, and in order to extend the writing life, it is necessary to increase the diameter of the ink containing tube to increase the ink filling amount.

Further, as an improvement of the above oil-based ballpoint pen, a ballpoint pen using a low-viscosity oil-based ink having excellent drying resistance is conceivable. However, the ink outflow amount also increases and the ink containing tube is extended in order to extend the writing life. It is necessary to increase the diameter of the ink and increase the amount of ink filled. Also, since the viscosity of the ink is low, if the tip side faces downward, a gap between the tip ball and the tip holding part will cause ink bleeding (direct current), and the amount of ink flowing out during writing will increase. There are drawbacks.

Since both the above-mentioned medium-viscosity water-based ink and low-viscosity oil-based ink have low viscosities, there is a phenomenon that the ink is likely to flow back or generate direct current. There is a risk of soiling clothes etc. if ink causes backflow or direct current. There is also a drawback that writing blurring is likely to occur due to a drop or knock impact. Further, if the writing tip of such a ballpoint writing instrument is inserted into a chest pocket or the like while protruding from the tip end opening of the tip shaft, there is a risk that ink will be sucked out and the clothes will be soiled.

Further, since a medium viscosity aqueous ball-point pen is usually filled with a grease-like semi-transparent non-drying substance called a follower at the rear end of the ink containing tube, the problem of ink evaporation prevention is a problem with the pen tip, that is, the ball. It may be considered to reduce evaporation from the gap between the holder and the holder. For example, if a solvent with a fairly low vapor pressure such as an oil-based ballpoint pen is mainly used, ink evaporation does not need to be considered. However, in the case of water-based ink, water is the main solvent, so evaporation of water cannot be prevented only by selecting a low vapor pressure solvent. In addition, since medium-viscosity water-based and low-viscosity oil-based ballpoint pens have a large ink storage tube, when mounted on a compound writing instrument of ordinary thickness, there is no freedom between the writing systems and the tip of the writing system is protruding. The tip hole of the cylinder is not centered smoothly, the operation is hindered, and the tip of the writing tip cannot be projected or retracted. Therefore, the shaft cylinder is extremely thick to enable the operation, and there is a drawback that portability and usability are deteriorated.

Further, by utilizing the difference in the solubility of the rubber component in the ink solvent, it is a gel in the ink containing tube, becomes a sol by the rotation of the tip ball during writing, gels in the state of drawing, and does not soak into the paper. Erasable ink is known.

[0008]

The above-mentioned conventional example has problems that metal parts are used in many parts, the structure is complicated, the number of parts is large, and the cost is high. Also, since the cap (rear shaft) is longer than the front shaft, there is a problem in flexibility in design. Also, when the cursive body is retracted, the shaft tip with one hand and the rear end of the shaft with the other hand. There is a drawback that it is not convenient because it is gripped and rotated. The first object of the present invention is to solve such a problem. A second problem is that it is possible to mount a ballpoint pen writing material filled with medium-viscosity water-based ink and low-viscosity oil-based ink, and the pen tip can be left with the cap removed while maintaining the drying resistance. In addition, it is possible to prevent backflow of ink and direct current of ink due to upward writing, and to prevent stains on clothes due to ink sucking even when the writing tip is inserted into a chest pocket or the like while protruding from the tip end opening. A third object is to provide a convenient double-sided writing instrument provided with a ball-point pen writing body that can be erased with an eraser and an eraser feeding mechanism.

[0009]

The multiple writing instrument of the present invention devised to solve the above-mentioned problems is integrated with the center shaft by fixing the front end of the front shaft and the front end of the center shaft in a non-rotatable and retaining manner. The cursive body is fitted in the guide grooves of the guide section so that it can be moved back and forth by urging the return spring between the guide section and the sliding piece. A circular cylindrical cam is provided rotatably with respect to the center shaft, and each sliding piece is brought into contact with the inclined surface of the cam to alternately move back and forth by the rotation of the cylinder cam with respect to the front shaft or the center shaft. In a multiple writing instrument whose tip can be selectively retracted from the tip opening of the tip shaft, a cylindrical cam is covered, and the rear shaft is fixed to the rear of the center shaft so as to be rotatable only, and the outer peripheral surface of the rear shaft. The clip is fixedly attached to the clip and is locked to the tip ball of the clip Is provided, and an axially long window portion is bored in the peripheral surface of the rear shaft facing the inside of the clip, and the locking projection provided on the outer peripheral surface of the cylindrical cam is projected into the window portion and the clip ball is provided. The cylindrical cam is stopped from rotating with respect to the rear shaft and positioned so as to be able to move backward in the forward direction by being locked to the locking portion of the cylindrical portion. When locked, each sliding piece is alternately moved back and forth by the rotation of the rear shaft with respect to the center shaft, so that the tip of each writing body can be selectively projected from the front shaft tip opening. As described above, since the number of parts is omitted and the structure is simpler than the conventional example, the assembly is facilitated and the cost can be reduced.
Further, since the rear shaft (cap) can be set to an appropriate length, there is flexibility in design and rotation operation becomes easy.
Also, even if the writing tip of the ballpoint writing system is still protruding from the tip opening of the tip shaft, you can avoid the risk that the writing tip will automatically get into the tip opening of the tip tip and stain your clothes by inserting the clip into the chest pocket. Becomes

An eraser feeding device integrally connected in the axial direction is disposed behind the cylindrical cam to cover the cylindrical cam and the eraser feeding device so that the rear shaft can rotate only behind the center shaft. The rear end portion of the eraser feeding device is appropriately projected from the rear shaft rear end hole while being attached, and the eraser can be retracted by rotating the rear end portion of the eraser feeding device with respect to the rear shaft.

Further, the tip containing the tip ball and the ink containing tube at the rear side, and the ink containing part of the ink containing tube is a non-deformable one having a relatively large cross-sectional area. A plurality of writing bodies including at least one ballpoint pen writing body in which a portion connecting the accommodating portion is formed in a flexible portion in the axial direction is mounted, and tips of the respective writing bodies are selectively selected from the tip of the shaft. Part can appear and disappear.
Therefore, there is no problem that the operation is obstructed and the writing tip portion cannot be projected or retracted, and the problem that the shaft cylinder becomes extremely thick and the portability and usability are deteriorated is solved.

In addition, a ball-point pen writing material can be erased with an eraser because a cross-linking substance is added to an ink solvent to turn into a sol by the rotation of a tip ball accompanying writing and gel in a state of drawing and does not soak into paper. To do.

The ball-point pen writing body is filled with an aqueous ball-point pen ink having a so-called shear thinning viscosity or a low-viscosity oil-based ink, which is discharged into the ink containing tube by virtue of a decrease in viscosity due to the rotation of the tip ball accompanying writing. The trailing end of the ink is filled with a follower made of a grease-like semitransparent non-drying material that moves following the consumption of the ink during writing.

Further, the ball-point pen writing body comprises a spring provided so that the tip ball is in constant contact with the inner edge of the ball-holding portion at the tip of the tip and is in close contact with the inner edge of the ball-holding portion, and the contact state is released during writing. If necessary, a valve chamber in which a ball valve is loosely fitted is provided in contact with the rear end of the tip,
At the rear of the valve chamber, there are provided a ball receiving seat that closely adheres to a ball valve to prevent backflow of ink, and a guide hole that leads from the ball receiving seat to the ink storage tube. Preventable.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, FIG. 1 shows a first embodiment of the compound writing instrument of the present invention. FIG. 2 shows a second embodiment of the compound writing instrument. FIG. 3 is a diagram illustrating a rotation restricting portion between the cylindrical cam and the center shaft of the compound writing instrument of the embodiment. FIG. 4 is a vertical cross-sectional view of a ballpoint pen writing body mounted on the compound writing instrument of the embodiment. FIG. 5 is a cross-sectional view of essential parts showing a state in the tip shaft portion in a state where a ballpoint pen writing body is mounted. The above-described example of the multiple writing instrument shows the one in which the mechanical pencil writing body 7 and the ordinary oil-based ballpoint pen writing body 8 are mounted. The front part has a writing instrument function, and the rear part has an eraser feeding mechanism. The compound writing instrument intended by the present invention is not limited to the above, but can be mounted with a ballpoint pen writing body filled with an aqueous or low-viscosity oil-based ballpoint pen ink having a so-called shear thinning viscosity or a ballpoint pen ink that can be erased with an eraser. Composed in combination with other cursive script depending on the gender. Further, the eraser feeding mechanism is laid according to the type and the necessity of writing materials to be combined. It is also possible to mount three cursive bodies.

As shown in FIG. 1, the compound writing instrument of the first embodiment has a center shaft 1, a tip shaft 3, a cylindrical cam 5, a pair of sliding pieces 6, 6 ', which are integrally provided with a guide cylinder 2. Mechanical pencil cursive writing 7, ballpoint pen cursive writing 8, rear shaft 4, inner cylinder 3
4. The eraser holder 40 and the eraser 45 are the main constituent elements. First, the center shaft 1 is made of resin, and is provided with a guide groove 9 that is long in the axial direction and opens in the side surface from approximately the center to the rear end, and a guide tube 2 that has a similar guide groove 9'on the side surface opposite to that. There is. In the first half of the guide tube 2, each guide groove 9, 9 '
A tubular portion 10 having a partition portion 16 having holes 32, 32 ′ communicating with the front end and having a front end opened is provided, and a step portion 31 is provided at a rear end of the tubular portion 10, and a front outer peripheral portion of the step portion 31 is provided. A bulging engagement portion 13 is formed on the. The guide cylinder may be provided separately from the center shaft, or may be formed as a guide part for guiding the sliding piece by integrally forming a rib or partition on the inner circumference of the center shaft 1.

Further, as shown in FIG. 3, a slit window 18 is formed on the rear side surface of the center shaft 1 to form a rotation restricting portion 19. The protrusion 17 of the cylindrical cam 5 is located in the cut window 18,
The cylindrical cam 5 rotates with respect to the center shaft 1 in a range in which the protrusion 17 contacts the one peripheral wall 50 of the slit window 18 and contacts the other peripheral wall 51. As will be described later, as the cylindrical cam 5 rotates, the writing tip portion of the mechanical pencil writing body 7 or the ballpoint pen writing body 8 is alternately projected and retracted from the tip tip opening.
Further, the mechanical pencil writing body 7 is in a protruding state at the position where the projection 17 contacts the peripheral wall 50, and the front end of the slit window 18 at that position becomes the front wall 52. At that time, an appropriate space is provided between the front end of the protrusion 17 and the front wall 52 to advance the cylindrical cam 5 in order to feed the lead of the mechanical pencil. or,
The ballpoint pen writing body 8 is in a protruding state at the position where the projection 17 contacts the peripheral wall 51, and the slit window 18 in which the projection 17 is located when the writing body is immersed and when the ballpoint pen writing body 8 is projected.
The front end of the front wall is a front wall 53 that is appropriately rearward of the front wall 52. At that time, the front end of the protrusion 17 and the front wall 53 are substantially in contact with each other, and the forward movement of the cylindrical cam 5 is blocked.

The front end of the tip shaft 3 is tapered, and the tip end of the inner hole portion is provided with an inner step portion 27. Further, the rear end hole is provided with an engaging groove 12 which is engaged with an engaging portion 13 provided on the outer peripheral portion of the tubular portion 10 of the guide tube and which prevents the tubular portion 10 from coming off and rotation. . The cylindrical portion 10 and the tip shaft 3 are detachably fixed with an appropriate force. (Actual development 6
(The same as the structure of the front shaft of Japanese Patent No. 4-3491) The connection between the front shaft 3 and the center shaft 1 may be screw connection.

The cylindrical cam 5 has a cylindrical shape and has a cam slope 14 which is circumferentially displaced forward and backward at a front edge thereof, and a notch 15 is formed at the frontmost end of the cam slope 14. Further, on the side surface of the cylindrical cam 5, there is formed a projection 17 which is located at the rotation restricting portion 19 of the center shaft 1 and which allows the cylindrical cam to rotate within a fixed range (approximately 180 degrees). Further, a locking projection 21 is formed on the rear side of the projection 17 on the same coaxial line, and the cylindrical portion 2 is further extended rearward.
0, and the spiral groove 33 is formed in the inner hole of the tubular portion 20. The locking projection 21 can be elastically deformed inward by making a notch in the periphery to facilitate attachment to the rear shaft 4 described later.

Further, the sliding piece 6 has a projection 22 on the outer surface thereof, and a central portion projects from the rear end surface of the projection 22 and both sides thereof have substantially the same slope as the cam slope 14 of the cylindrical cam 5 described above. It has a slope. Further, there is provided a hole that abuts on the flange portion 24 of the core pipe 23 and projects and fits behind the core pipe 23 for a long time. Similarly to the sliding piece 6, the sliding piece 6'has a projection 22 'and a cam slope, and an engaging portion 26 for fixing the rear end of the writing body 8 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 7 incorporates a general chuck mechanism, is joined to the core pipe 23 via a joint 29 connected to the chuck mechanism at the rear end, and has a flange portion 24 provided at the rear of the core pipe 23. The sliding piece 6 is fitted in contact with the sliding piece 6, and the rear end hole of the core pipe 23 protruding from the rear end of the sliding piece 6 is closed by a tail plug 25 or the like. The lead-out is performed by moving the chuck by the axial transition of the sliding piece 6 in a state where the step portion 28 at the tip of the mechanical pencil writing body 7 is in contact with the inner step portion 27 of the tip shaft 3.

By the way, the rotation restricting portion 19 is provided on the center shaft 1.
A circumferential flange portion 1a is appropriately formed on the front side surface, and a projecting locking portion 1b is formed near the rear portion of the flange portion 1a.
Further, a circumferential groove-shaped engagement portion 4b is formed in the front end inner hole of the rear shaft 4. A clip 46 is integrally formed on the side surface of the outer peripheral portion. (Of course, it may be fixed and provided separately)
Further, a window portion 4a that is long in the axial direction is formed in the rear shaft side surface corresponding to the inside of the clip 46, and a hole portion 48 that serves as a locking portion is formed in the ball portion 47 at the tip of the clip. The rear shaft 4 is fitted so as to cover the cylindrical portion 20, and the cylindrical cam 5
Of the locking projection 21 elastically fits into the window portion 4a, and the locking portion 4b elastically engages with the locking portion 1b. As described above, the rear shaft 4 is fixed to the center shaft 1 so as to be rotatable, and the cylindrical cam 5 is stopped to rotate relative to the rear shaft 4 so as to be movable back and forth.

The inner cylinder 34 is a resin cylindrical body having a collar-shaped crown 35 at the rear end, a bottom 37 at the front and a locking portion 38 at the tip. Further, a pair of slits 36 facing each other are formed on the side surface of the cylindrical portion connecting the crown 35 and the bottom portion 37. An eraser holder 40 having an eraser 45 attached to the rear end is mounted in the inner cylinder. Eraser holder 40
A pair of elastic pieces 43 sandwiching the eraser 45 are formed on the rear side of the elastic piece 43, and the elastic pieces 43 have locking projections 44 on their inner surfaces. A projection 42 is formed on the outer circumference of the front cylindrical portion 41. The eraser holder 40 has a protrusion 42 and an elastic piece 43.
Is fitted in the slit 36 of the inner cylinder portion, and the protrusion 42 is further fitted in the spiral groove 33, and is disposed in the inner cylinder 34.

As described above, the inner cylinder 34 is fitted into the cylindrical portion 20 of the cylindrical cam while rotating appropriately so that the projection 42 of the eraser holder is engaged with the spiral groove 33 of the cylindrical portion 20, and the crown 3
5 contacts the rear end of the cylindrical portion 20, and the locking portion 38 of the inner cylinder is locked to the step portion 39 provided in front of the inner hole of the cylindrical portion 20 so that the inner cylinder 34 rotates only relative to the cylindrical portion 20. It can be prevented from coming off. As described above, when the crown 35 is rotated with respect to the rear shaft 4, the eraser holder 40 moves back and forth so that the eraser 45 can be retracted from the rear end hole 35a of the crown.

Next, the assembly order will be described. The mechanical pencil writing body 7 and the ballpoint pen writing body 8 are connected to the respective sliding pieces 6 and 6'at the rear ends thereof, and the guide rod 2 of the above-mentioned middle shaft is connected.
Is slidably fitted in the guide grooves 9 and 9'of each of the above, and the front end surface of each sliding piece 6 and 6'and the partition portion 16 on the front of the guide grooves 9 and 9 '
It is urged rearward by the return springs 30 and 30 interposed between and. Subsequently, the cylindrical cam 5 is inserted into the rear end hole of the center shaft 1 to position the protrusion 17 on the rotation restricting portion 19, and the rear shaft 4 is fitted to the outside of the cylindrical cam to attach the locking protrusion 21 to the window portion 4a. The rear shaft 4 is rotatably fixed to the center shaft 1 by allowing the rear shaft 4 to extend and engage the locking part 4b with the locking part 1b. With the above, the cylindrical cam 5 is approximately 180 degrees in the circumferential direction relative to the center shaft 1.
It is rotatably positioned in degrees.

Further, with the locking projection 21 locked to the rear end of the hole 48 of the clip ball 47, and the mechanical pencil writing body 7 is projected, the cylindrical cam 5 is extended to the center shaft 1. It is possible to move back and forth by the stroke required for
When the cursive body is stored or when the ballpoint pen cursive body 8 is in a protruding state, it cannot move forward and backward. Since the sliding pieces 6, 6'are always urged rearward by the return springs 30, 30 ', the cam slopes of the protrusions 22, 22' are always kept in contact with the cam slope 14 of the cylindrical cam 5. ing.

Also, with the rear end surface of the front shaft 3 in contact with the front surface of the stepped portion 31 of the center shaft 1, the engagement portion 13 of the tubular portion 10 is elastically fitted into the engagement groove 12 of the front shaft 3. As a result, the front shaft 3 and the center shaft 1 are fixed in a rotation-stopping and slip-out preventing state. The front axle 3 can be attached and detached with an appropriate force. In this state, when the rear shaft 4 is rotated to one side with respect to the front shaft 3 or the center shaft 1, the sliding piece 6 moves forward and the notch 15 at the front end of the cam slope 14 of the cylindrical cam 5 is moved.
Is locked to the projection 22 of the sliding piece 6 of the mechanical pencil writing body 7, and the writing tip portion is projected from the tip end opening.
Further, when the cylindrical cam 5 is rotated to the other side with respect to the leading shaft 3 or the center shaft 1, the sliding piece 6 is retracted, the writing tip of the mechanical pencil writing body 7 is retracted from the leading end of the leading axis, and the sliding piece is moved. 6 ”moves forward, and the writing tip of the other ball-point pen writing body 8 projects from the tip tip opening.

On the other hand, the eraser holder 40 to which the eraser 45 is fixed is inserted into the inner cylinder 34 from the rear end of the cylindrical portion 20 of the cylindrical cam while being rotated, and the crown 35 is inserted.
Is fastened to the tubular portion 20 only in the rotational direction with the front end of the abutting against the rear end of the tubular portion 20. From the above, the rear axle 4
On the other hand, when the crown 35 is rotated left and right, the rear end hole 35a of the crown is rotated.
The eraser 45 appears and disappears.

FIG. 2 shows a second embodiment of the present invention, which is basically the same as the first embodiment. Only the differences will be outlined below. First, the spiral groove 66 is formed in the inner bore of the tubular portion in front of the inner barrel 65. Further, a locking portion 62 is formed near the rear end of the shaft portion 61, and a tubular portion having a slit 63 is further extended rearward. In addition, the inner cylinder 65 is fitted to the cylindrical portion of the cylindrical cam having a slit and is provided with a locking portion 68 that locks the locking portion 62 of the cylindrical cam only in the rotational direction. The crown 67 is formed to project from the rear end of the rear shaft 64. As described above, when the crown 67 is rotated right and left with respect to the rear shaft 64, the eraser can be retracted from the rear end hole.

Next, the ballpoint pen writing body 70a mounted on the multiple writing instrument of the present invention will be described. Note that the ball-point pen writing body 1a and the ball-point pen writing body 70b shown in FIG. 5 have the same structure, for example, different ink colors. In addition, the ink applied to the ballpoint pen writing material is a water-based, low-viscosity oil-based ink having a so-called shear thinning property, or a cross-linking substance is added to the ink solvent, so that the tip ball is rotated during writing to form a sol, and in a drawing line It is an ink that can be erased with an eraser because it gels and does not soak into the paper.

As shown in FIG. 4, the tip 80 is crimped so that the tip ball 81 is rotatably held in a state where the tip ball 81 is substantially in contact with a seat having a channel into which ink can flow. . Further, the spring 83 is inserted into the inner hole of the tip 80, and the rear end of the shaft portion 82 of the tip is appropriately crimped so that the rear end of the spring 83 cannot be pulled out. Further, it is very important that the tip ball 81 is in close contact with the inner surface of the tip holding portion for the purpose of drying the writing tip and preventing direct current of the ink. For this reason, the surface roughness of the tip inner surface holding the tip ball and caulking The inner surface is ground to improve the close contact accuracy, and the secondary plastic working is performed to increase the crimping accuracy. In addition, surface treatment and the like are taken into consideration on the contact surface with the tip ball.

Further, the tip of the spring 83 becomes an upright rod shaft portion 84, and the tip of the rod shaft portion 84 has a tip ball 81.
It comes into contact with the rear end in the pressed state. The tip ball 81 is brought into close contact with the inner edge of the ball holding portion (formed by caulking or the like) of the chip 80 by its pressing.

Further, the joint 71 is formed with a front shaft portion 72 for crimping the shaft portion 82 of the tip 80 and a rear shaft portion 74 for crimping the front end of the ink containing tube 86 at the tip. It is formed of a flexible resin molded product that is integrally connected to the portion 74, for example, by a bellows 73. A valve chamber 76 in which a ball valve 85 is loosely fitted is provided behind the inner hole of the front shaft 72, and a tapered or spherical ball receiving seat 77 and an axial center are appropriately provided behind the valve chamber 76. An eccentric guide hole 78 is provided, and the inner holes of the bellows 73 and the rear shaft portion 74 communicate with the inner hole of the ink containing tube 86. In addition, a groove is provided on one side of the inner wall of the valve chamber 76 so that ink flows in the axial direction. The ball valve 85, which is loosely fitted in the valve chamber 76 (not shown), contacts the biased rear end of the shaft portion 82 of the chip to form an ink flow path when the chip 80 is directed downward. Then, the ink in the ink containing tube flows through the guide hole 78 and flows into the inner hole portion of the chip through the groove portion, the ink flow path and the like. Conversely, in the upward state, the ball valve 85 comes into contact with the ball receiving seat 77 to provide a function of preventing backflow of ink.

The ink 87 of the ball-point pen is filled in the ink containing tube 86, and the rear end of the ink 87 is a grease-like half which can be moved by contacting the ink surface as the ink is consumed. A follower 88 made of a transparent non-drying substance is filled. Further, a resin follower rod 89 having a specific gravity substantially equal to that of the follower 88 is immersed in the follower 88 as needed in order to prevent deformation due to dropping or knocking impact. As the ink containing tube 86, a transparent PP resin molded product or the like is used as an example. Also, select the ink storage tube with a material with excellent clear drainage. Further, the ink containing tube 86 may be formed integrally with the joint 71.

Further, the ink containing portion of the ink containing tube 86 is a non-deformable one having a relatively large cross-sectional area, and has, for example, a substantially D-shaped cross-sectional shape to be inserted into the center shaft 1 without waste. Formed. The portion connecting the tip 80 and the ink containing portion can be easily displaced laterally with respect to the axial direction. It is also possible to connect a thin and thin flexible tube between the joint for pressing the rear end of the tip 80 and the ink containing tube. When the ballpoint pen writing bodies 70a and 70b are mounted on the compound writing instrument, for example, the ballpoint pen writing body is connected via the connecting portion 90 or the like connected to the sliding piece.

[0036]

First, in the first embodiment, when the rear shaft 4 is rotated to one side with respect to the front shaft 3 or the center shaft 1, it is provided at the tip of the cam slope 14 of the cylindrical cam 5 as shown in FIG. The notch 15 engages with the sliding piece 6 of one of the mechanical pencil writing bodies 7 so that the writing tip portion thereof projects from the tip end opening of the tip shaft. In this state, when the rear end of the crown 35 is knocked and the cylindrical cam 5 is axially moved, the operation is transmitted to the sliding piece 6, the core pipe 23, and the mechanical pencil writing body 7, and the step portion 28 at the writing tip portion is moved. The chuck moves axially together with the joint 29 from the state in which the chuck is in contact with the inner step portion 27 of the leading shaft 3 and the core is fed. Further, when the rear shaft 4 is rotated to the other with respect to the front shaft 3 or the center shaft 1, the mechanical pencil writing body 7 is retracted, and instead, the ballpoint writing system 8 is used.
The writing tip of the sticker sticks out from the tip end of the tip shaft. Next, rear axle 4
On the other hand, when the crown 35 is rotated left and right, the eraser holder 40 moves back and forth, and the eraser 45 appears and disappears from the rear end hole 35a. Also, the second embodiment is the same as the first embodiment, and the description thereof is omitted.

In the ballpoint pen writing body 70a, the ball valve 85 is disposed in the valve chamber 7 with the tip 80 facing upward.
Since the guide hole 78 is located at the ball receiving seat 77 of No. 6 and seals the guide hole 78, even if the ink immediately below the tip ball 81 of the chip runs out and the ink runs out, the head does not hit the ink and does not flow back. Therefore, when the tip 80 is turned downward, the ink can immediately flow out, and blurring in writing can be prevented. (By the way, in the structure without the ball valve, the ink works in the backward direction in the upward writing, so air is trapped in the tip, and the ink does not immediately follow up in the downward writing, causing blurring.)

In the writing state with the tip 80 facing downward, the ball valve 85 abuts on one side of the rear end of the tip 80 in a biased state, and the other side has a flow passage through which ink can flow into the tip 80. Then, the ink 87 that has entered the valve chamber 76 from the ink containing pipe 86 through the guide hole 78 is guided to the rear end of the front end ball 81. In this state, the tip end ball 81 is brought into close contact with the inner edge of the chip holding portion by the pressing of the rod shaft portion 84, so that direct current of ink is prevented. Also, the tip ball 81 is
The ink is allowed to flow out because of a slight retreat, and the ink is allowed to flow out smoothly by the rotation of the tip ball 81 during writing, and it is possible to perform writing with a high degree of handwriting density without fluffing.

Directly below the tip ball 81, there is a channel (tip ball receiving seat having ink inflow grooves penetrating toward the inner hole of the chip at a plurality of locations), and a rod shaft portion 84 penetrates the center hole of the channel. . The ink in the chip is guided to just below the tip ball 81 through the ink inflow groove and the gap between the center hole and the rod shaft portion 84.

[0040]

As described above, according to the present invention, metal is replaced by 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 can be reduced. Further, since the rear shaft (cap) can be set to an appropriate length, there is flexibility in design and rotation operation becomes easy. In addition, a ballpoint pen writing body using a water-based, low-viscosity oil-based ink with so-called shear thinning is mounted,
It has no burrs, dark lines, no blurring of writing, and the tip of the writing can be retracted without the need for a cap. In addition, direct current of ink, upward writing, backflow of ink against knocking and drop impact causes the ink to flow in the barrel or hand. There is no accident to stain clothes or clothes,
Alternatively, it is possible to provide a convenient double-sided writing instrument equipped with a ballpoint pen writing instrument or a mechanical pencil writing instrument that uses ink that can be erased with an eraser, and a convenient writing instrument with an eraser feeding mechanism, with a shaft thickness that satisfies portability and usability. .

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an entire compound writing instrument of a first embodiment of the present invention, which is partially shown in non-cross section.

FIG. 2 is a vertical cross-sectional view showing the entire compound writing instrument of the second embodiment of the present invention, which is partially shown in non-cross-section.

FIG. 3 is an explanatory view showing an engagement state between a protrusion of a cylindrical cam and a rotation restricting portion of a center shaft.

FIG. 4 is a vertical cross-sectional view of a ballpoint pen writing material according to an embodiment.

FIG. 5 is a cross-sectional view showing a main part in a tip shaft when a ballpoint pen writing body according to an embodiment is mounted.

[Explanation of symbols]

1 center axis 1a Tsuba part 1b Locking part 2 Guide tube 3 tip axis 4 rear axle 4a window 4b Locking part 5 Cylindrical cam 6 sliding pieces 6 "sliding piece 7 Mechanical pencil cursive 8 Ballpoint pen cursive 9 guide groove 9'guide groove 10 tube 11 knock spring 12 engagement groove 13 Engagement part 14 Cam slope 15 notches 16 partition 17 Protrusion 18 cut window 19 Rotation restriction part 20 tube 21 Locking protrusion 22 protrusion 22 'protrusion 23 core pipe 24 Flange 25 tail plug 26 Locking part 27 Inner Step 28 steps 29 joints 30 return spring 30 'return spring 31 steps 32 holes 32 holes 33 spiral groove 34 Inner cylinder 35 Crown 35a Rear end hole 36 slits 37 bottom 38 Locking part 39 steps 40 eraser holder 41 Tube 42 protrusion 43 Elastic piece 44 Locking protrusion 45 eraser 50 perimeter wall 51 peripheral wall 52 front wall 53 front wall 60 cylindrical cam 61 Shaft 62 Locking part 63 slits 64 rear axle 65 Inner cylinder 66 spiral groove 67 Crown 68 Locking part 70a Ballpoint pen cursive 70b Ballpoint pen cursive 71 joint 72 Front shaft 73 Bellows 74 Rear axle 75 Tsuba 76 valve chamber 77 Ball seat 78 guide hole 79 Inner hole 80 chips 81 tip ball 82 Shaft 83 spring 84 Bar shaft 85 ball valve 86 Ink storage tube 87 ink 88 Follower 89 Follower Stick 90 Connection

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B43K 24/18 B43K 7/02 B43K 7/08 B43K 25/02 B43K 29/02

Claims (2)

(57) [Claims] 1. A plurality of guide grooves of the guide portion are provided with return springs for urging the writing body to the rear between the guide portion and the sliding piece so that the respective writing bodies can be fitted back and forth. Then, each sliding piece is brought into contact with the cam slope of the cylindrical cam and moved back and forth alternately by the rotation of the cylindrical cam with respect to the guide portion, whereby the tip of each cursive body can be selectively retracted from the tip opening of the tip shaft. In the compound writing instrument, the first writing instrument is a mechanical pencil writing instrument, the second is a ballpoint pen writing instrument, and the ballpoint writing instrument has the tip of the joint and the ink on the rear end of the joint. The accommodating tube is fixed, and a joint connecting the tip and the ink accommodating portion is provided so as to be easily displaceable in the lateral direction with respect to the axial direction. Normally closely pressed against the inner edge of the Le holding portion has a spring that is provided so as to close contact state is canceled at the time of writing, and the ink reservoir is
The inside of the ink is filled with a water-based ball-point pen ink having a so-called shear thinning viscosity or a low-viscosity oil-based ink, which is discharged by decreasing the viscosity due to the rotation of the tip ball accompanying the writing, and further the ink accompanying the writing at the rear end of the ink. A writing instrument characterized in that it is filled with a follower composed of a grease-like semitransparent non-drying material that moves following the wear of the compound. 2. A plurality of guide grooves of the guide portion are provided with return springs for biasing the writing body rearward between the guide portion and the sliding piece so that the respective writing bodies can be fitted back and forth. Then, each sliding piece is brought into contact with the cam slope of the cylindrical cam and moved back and forth alternately by the rotation of the cylindrical cam with respect to the guide portion, whereby the tip of each cursive body can be selectively retracted from the tip opening of the tip shaft. In the compound writing instrument described above, the rear shaft is rotatably fixed to the rear of the guide portion by covering the cylindrical cam, and a clip is provided on the outer peripheral side surface of the rear shaft to lock the ball portion at the tip of the clip. Is formed, a window portion that is long in the axial direction is bored on the peripheral surface of the rear shaft facing the inside of the clip, and a locking projection is provided on the outer peripheral surface of the cylindrical cam. The projection protrudes into the window and the ball at the tip of the clip is locked. The cylindrical cam is stopped from rotating with respect to the rear shaft and positioned so as to be able to move backward, and the locking projection is locked to the locking portion of the ball portion at the tip of the clip at the forward position of the cylindrical cam. At the same time, each sliding piece is moved back and forth alternately by the rotation of the rear shaft with respect to the guide part.
It is configured such that the tip of each cursive body can be selectively projected from the tip of the front shaft, and the cursive body is composed of a mechanical pencil cursive body as the first body and a ballpoint pen cursive body as the second body. Has a spring provided so that the tip ball is always pressed against the inner edge of the ball holding portion at the tip of the tip to come into close contact with the tip, and the close state is released at the time of writing. The viscosity decreases by the rotation of the ink and is discharged, so-called water-based ballpoint pen ink with so-called shear thinning viscosity or low viscosity oil-based ink is filled, and the ink is moved to the rear end of the ink following the consumption of the ink accompanying writing. A compound writing instrument comprising a follower made of a translucent non-drying substance in the form of grease.