JP3602273B2 - Double writing instrument - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a double-type writing implement equipped with a ballpoint pen writing body filled with an aqueous (called medium viscosity), low-viscosity oil-based ballpoint pen ink having a shear thinning property.
[0002]
[Prior art]
2. Description of the Related Art In general, there is known a double-type writing instrument having a plurality of writing objects such as a ball-point pen mounted thereon so that a writing tip can be selectively protruded and retracted from an axis.
In addition, as a retracting mechanism of the writing tip of the double-type writing instrument, a knocking type, a slider type that alternately slides a slider protruding from the side of the shaft cylinder of the writing instrument, and a cam cylinder having an inclined surface are rotated. Various types such as a cam type are known.
Since the conventional retracting mechanism has a built-in return spring for returning the writing body to the inside of the barrel, there is a problem that the structure is complicated, the number of parts is large, and the cost is high.
Further, the space for incorporating the mechanism is large, and the degree of freedom of the refill shape is small.
[0003]
On the other hand, medium-viscosity water-based and low-viscosity oil-based ballpoint pens have thick ink storage tubes. The center of the writing tip is not smoothly centered on the tip end of the cylinder, so that the operation is hindered and the tip of the writing tip cannot appear or disappear. Therefore, the shaft cylinder becomes extremely thick in order to enable the operation, and there is a disadvantage that portability and usability deteriorate.
[0004]
The water-based ballpoint pen has a low viscosity of several mPa · S or less, and therefore has an advantage that it can be written with a light writing pressure, and has a characteristic of good writing taste. However, there is a drawback that a direct current phenomenon in which the ink flows gently from the pen tip and a reverse flow phenomenon in which the air flows in from the tip of the ballpoint pen and the ink flows out easily occur. A method of preventing these phenomena by using a bundle of fibers called batting is used.
Further, if left in a cap-off state, there is a problem that the vapor pressure of the solvent is high and the solvent is leaked, so that the leading end is dried and the ink does not flow out, making it impossible to write.
[0005]
On the other hand, conventionally known oil-based ball-point pens have high resistance when the ball rotates when the ink flows out of the pen tip due to the high viscosity of the ink used for it being several thousand mPa · S or more. There is a drawback that writing is bad. In addition, there is a problem in that the amount of ink flowing out from the tip during writing is small, there is a dent phenomenon, the writing line is uneven, the writing density is low, and a high writing pressure is required.
As an improvement of the oil-based ball-point pen, recently, a ball-point pen for water-based ink called medium viscosity using an ink having an intermediate viscosity region between the above-mentioned water-based and oil-based (several mPa · S to several thousand mPa · S) has been developed. This is a ball-point pen using a relatively low-viscosity water-based ink having a characteristic that the viscosity is reduced by the rotation of the tip ball and the ink flows smoothly, that is, a so-called shear thinning property. However, since this ink has a drawback that the ink easily dries, a cap for sealing the writing tip is usually required. In addition, the amount of outflow of ink increases, and it is necessary to increase the diameter of the ink storage tube and increase the amount of ink to be filled in order to extend the writing life.
[0006]
As an improvement of the above-mentioned oil-based ballpoint pen, a ballpoint pen using a low-viscosity oil-based ink having excellent drying resistance can be considered. However, the outflow of the ink is increased, and the diameter of the ink storage tube is increased in order to extend the writing life. It is necessary to increase the thickness and the filling amount of the ink. In addition, since the viscosity of the ink is low, if the tip side faces downward and a gap is formed between the tip ball and the tip holding portion, the ink bleeds (direct current) or the amount of ink flowing out during writing increases. There are drawbacks.
[0007]
Since both the above-mentioned medium-viscosity aqueous ink and low-viscosity oil-based ink have low viscosities, there is a phenomenon that the ink easily flows backward or direct current. If the ink causes backflow or direct current, there is a risk of soiling clothes and the like. In addition, there is a drawback that handwriting is apt to occur due to drop or knock impact.
In addition, there is also a problem that clothes are stained when the device is mounted on a writing instrument and inserted into a breast pocket or the like with the writing tip protruding.
In addition, a medium-viscosity water-based ball-point pen is usually filled with a grease-like translucent non-drying substance called a follower at the rear end of an ink storage tube. What is necessary is just to consider the reduction of evaporation from the gap. For example, if a solvent having a considerably low vapor pressure such as an oil-based ballpoint pen is mainly used, the evaporation of the ink need not be considered. However, in the case of the water-based ink, water is the main solvent, and therefore, evaporation of water cannot be prevented only by selecting a low vapor pressure solvent.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-described problems of the prior art, that is, by mounting a plurality of writing bodies in a barrel, and allowing the writing tip of each writing body to selectively appear and disappear from the barrel tip. Another object of the present invention is to provide a double-type writing instrument excellent in manufacturing cost, portability, and usability. In addition, there is no backflow of ink and no direct current phenomenon, the drying resistance of the pen tip is maintained and the cap can be removed and left alone, and the impact of drop impact, reverse flow of ink due to upward writing and direct current of ink are prevented. Construct a cursive medium of medium viscosity aqueous, low viscosity oily ballpoint pen with a mechanism,
By mounting the ballpoint pen writing body in two types of barrels, the writing tip of each writing body can be selectively protruded and retracted from the barrel barrel tip, and inserted into a breast pocket etc. while the writing tip is projected. It is possible to provide a convenient double-type writing instrument that does not stain clothes.
[0009]
[Means for Solving the Problems]
The dual writing implement of the present invention is a dual writing implement equipped with two types of ballpoint pen writing bodies, and each writing tip can be alternately protruded and retracted from the tip opening of the front spindle. An operating body fixed to the rear end of the rotating shaft, which is rotatably disposed in the inner hole of the rear shaft within a range of approximately 180 degrees with respect to the rear shaft, and protrudes from the rear end of the rear shaft; A pair of sliding pieces are arranged on the outer circumference of the shaft, a ballpoint pen writing body is provided in front of each sliding piece, and a spring is provided between the operating body and the rear end of the rear shaft. The body and the rotating shaft can be moved forward as needed, and the rotating shaft is urged rearward with the rear shaft stopped at the rear end, at which time the rotating shaft and the rear shaft engage with each other to engage the rear shaft. The rotation shaft is prevented from rotating, and the rotation shaft can rotate when the operation body rotates while maintaining the state in which the operating body is appropriately advanced with respect to the rear shaft. In conjunction with the rotation of the rotating shaft caused by the rotation of the body, configured to writing tip of and moved back and forth alternately sliding piece each have respective cursive is retractable from front barrel tip opening.
[0010]
Also, the ballpoint pen writing body has a tip for holding the tip ball and an ink storage tube at the rear, and the viscosity decreases due to the rotation of the tip ball accompanying the writing into the ink storage tube. Is filled with a water-based ballpoint pen ink or a low-viscosity oil-based ink, and a back end of the ink is filled with a follower made of a grease-like translucent non-drying substance that moves following consumption of the ink accompanying writing. Wherein the ink storage portion of the ink storage tube is a non-deformed one having a relatively large cross-sectional area, and the portion connecting the tip and the ink storage portion is easily formed in the lateral direction with respect to the axial direction. It is possible to change.
[0011]
In addition, the ballpoint pen writing body has a spring provided so that the tip ball always presses and closely contacts the inner edge of the ball holding portion at the tip end of the tip, and the contact state is released during writing.
Also, the ballpoint pen writing body is provided with a valve chamber in which a ball valve is loosely fitted in contact with the rear end of the chip, and the ball valve is in close contact with the rear of the valve chamber to prevent backflow of ink and the ball receiving seat. A guide hole is provided from the seat to the ink storage tube.
[0012]
In addition, a clip provided from one side of the operating body toward the front of the rear shaft, and a bulging portion provided at a predetermined position on the rear shaft peripheral surface in contact with the ball portion of the clip, the operating body is rotated. Only in a state where the writing tip protrudes from the tip end of the front shaft, the gap between the ball portion of the clip and the bulging portion is engaged so that the clip cannot be inserted into a breast pocket or the like. .
[0013]
【Example】
First, FIGS. 1 to 7 show an embodiment of the present invention. In FIG. 1, two ballpoint pen writing bodies 1a and 1b are provided.
The double-type writing implement intended by the present invention uses a ball-point pen writing material filled with an aqueous or low-viscosity oil-based ball-point pen ink having a so-called shear thinning property.
[0014]
1 includes a front shaft 49 and a rear shaft 30 that house a portion of a writing tool mechanism located at a front portion, and an operating body 40 disposed at a rear end of the rear shaft. A female screw 49a is formed on the inner periphery of the rear portion of the front shaft 49.
A male screw 32 is formed at a front portion of the rear shaft 30, and is screwed with the female screw 49a of the front shaft 49, and is removed as necessary to replace a writing body.
A rib 30a for preventing rotation is formed on the inner periphery of the rear end of the inner hole of the rear shaft 30 for restricting a rotation range of a rotation shaft 33, which will be described later, and the rear shaft 30 has a rear end stepped portion 30b. Four guide ribs 31 formed in the axial direction at 90-degree intervals are formed on the front inner peripheral portion of 30.
Also, bulging portions 39 are formed at two locations facing the outer periphery of the rear shaft 30 slightly rearward, and a convex portion 39a and a concave portion 39b are provided on the front side of each bulging portion.
[0015]
The rotating shaft 33 has a small diameter portion 34 in front of the large diameter portion 36, and a spiral cam groove 35 is formed on the peripheral surface of the small diameter portion 34. Also, a circumferential groove 36a cut out at the rear end side of the large diameter portion peripheral surface located behind the cam groove 35 and a narrow vertical groove 36e cut out at the front end at the center position of the groove 36a are formed. Have been. As will be described later, a rib is formed on the inner periphery of the rear end of the rear shaft 30, and the rib slides in the groove 36a in the rotation direction within a range of approximately 180 degrees, and the rib fits into the vertical groove 36e and rotates. It is configured to be blocked.
Further, a locking portion 38 having a shaft portion 37 at the rear of the large diameter portion 36, further having a shaft portion 38a having a reduced diameter at the rear thereof, and having a flange portion 38b at the rear end of the shaft portion, Further, a detent groove 38d is provided at a required position of the shaft portion 38a.
[0016]
The operating body 40 is formed of a tubular portion 40a that is provided on the rear end portion 40b of the rear shaft 30, and a clip 40c that extends forward from one side surface of the outer peripheral portion of the tubular portion 40a. A ball portion 40d is provided inside the clip 40c, and a rib (not shown) provided on a peripheral surface of the shaft portion 38a of the rotary shaft 33 is provided in a hole of the rear end portion 40b of the cylindrical portion 40a. As will be described later, the flange 38b of the rotating shaft 33 protrudes from the rear end of the rear end 40b, and the rotating shaft 33 and the operating body 40 are fixed.
A crown 42 is fixed to the rear end of the operation body 40.
[0017]
Insertion holes 45a, 45b are provided in front of the sliding pieces 43a, 43b, and in the respective insertion holes, locking portions 46a, 46b of inward ridges for fixing rear ends of ballpoint pen writing bodies 1a, 1b described later. Is provided. Protrusions 44a and 44b are formed on the inner surface on the rear side so that each sliding piece can move back and forth by pressing the cam groove 35 with the rotation of the rotating shaft 33.
Grooves 48a and 48b are provided on the outer circumference of the sliding pieces 43a and 43b so as to stop and engage the guide ribs 31 of the rear shaft 30.
Accordingly, the grooves 48a, 48b provided on the side surfaces of the sliding pieces 43a, 43b engage with the guide ribs 31, respectively, so that the sliding pieces 43a, 43b are smoothly moved back and forth. The cross-sectional shape of the sliding pieces 43a and 43b is substantially D-shaped. Therefore, there is an advantage that a complicated structure for mounting a guide cylinder having two opposing guide grooves, which is often shown in the conventional example, is not required.
The sliding pieces 43a and 43b are in contact with each other on their flat sides, but in order to make the sliding between them smoother, a guide projection 47b is provided on the sliding piece 43b, and a guide projection 47b is provided on the sliding piece 43a. A guide groove 47a for fitting is provided.
[0018]
The rotating shaft 33 is inserted into the inner hole of the rear shaft 30 with the protrusions 44a, 44b of the sliding pieces 43a, 43b engaged with the cam groove 35, and formed on the inner periphery of the rear end of the rear shaft 30. The rib 30a fits into the vertical groove 36e of the rotary shaft, the rear end of the large diameter portion 36 comes into contact with the rear end step 30b of the rear shaft, and the operating body is inserted into the rear end shaft of the rotary shaft 33. 40 is fixed. At this time, a spring 41 is biased between the inner step of the operating body 40 and the rear end of the rear shaft 30. As described above, the rib 30a slides in the groove 36a in the rotation direction within a range of approximately 180 degrees so that the rib 30a fits into the vertical groove 36e and the rotation shaft 33 is prevented from rotating with respect to the rear shaft 30. Be composed.
[0019]
By rotating the operating body 40 with respect to the rear shaft 30 while maintaining the state of advancing, the rotating shaft 33 rotates, with which one sliding piece advances and the other sliding piece retreats. (State in FIG. 1) The rear ends of the ballpoint pen writing bodies 1a and 1b are fixed to the insertion holes 45a and 45b of the sliding pieces 43a and 43b, and the front shaft 49 is fixed in front of the rear shaft 30.
[0020]
Next, the ballpoint pen writing body 1a mounted on the compound writing instrument of the present invention will be described. Note that the ballpoint pen writing bodies 1a and 1b have the same configuration, for example, different ink colors.
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.
[0021]
As shown in FIG. 6, the tip 11 is caulked so that the tip ball 12 is rotatably held in a state where the tip ball 12 is substantially in contact with a seat having a channel into which ink can flow. A spring 14 is inserted into the inner hole of the chip 11, and the rear end of the shaft 13 of the chip is appropriately caulked so that the rear end of the spring 14 cannot be pulled out. In addition, it is extremely important that the tip ball 12 is in close contact with the inner surface of the tip holding portion for drying the writing tip and preventing direct current of ink. Therefore, the surface roughness of the tip inner surface holding the tip ball and the caulking are important. In order to improve the close contact accuracy, grinding of the inner surface is performed, and secondary plastic working to increase the crimping accuracy is considered. In addition, a surface treatment or the like is taken into consideration for the surface in close contact with the tip ball.
[0022]
Further, the tip of the spring 14 becomes a linear rod portion 15, and the tip of the rod portion 15 contacts the rear end of the tip ball 12 in a pressed state. The tip ball 12 is brought into close contact with the inner edge of the ball holding portion (formed by caulking or the like) of the chip 11 due to the pressing.
[0023]
The joint 2 has a front shaft portion 3 for pressing the shaft portion 13 of the chip 11 at the tip and a rear shaft portion 5 for pressing against the front end of the ink storage tube 17 at the front end. The space between them is formed of a flexible resin molded product integrally connected by, for example, a bellows 4 or the like. Further, a valve chamber 7 in which a ball valve 16 is loosely fitted is provided behind the inner hole of the front shaft section 3, and a tapered or spherical ball receiving seat 8 is provided behind the valve chamber 7 and a ball seat 8. An eccentric guide hole 9 is provided, and the inner holes of the bellows 4 and the rear shaft portion 5 communicate with the inner hole of the ink storage tube 17. A groove is provided on one side of the inner wall of the valve chamber 7 so that ink flows in the axial direction. When the tip 11 is turned downward, the ball valve 16 which is loosely fitted in the valve chamber 7 contacts the rear end of the shaft 13 of the tip to form an ink flow path. Then, the ink in the ink storage tube flows into the chip inner hole through the groove 9 and the ink flow path through the guide hole 9. Conversely, in the upward state, the ball valve 16 comes into contact with the ball receiving seat 8 to obtain a function of preventing the ink from flowing backward.
[0024]
The ink reservoir 17 is filled with the ink 18 of the above-mentioned ball-point pen, and the rear end of the ink 18 is a grease-like translucent non-drying material that can move following the ink surface as the ink is consumed. A follower 19 made of a material is filled. Further, a resin follower rod 20 having a specific gravity substantially equal to that of the follower 19 is immersed in the follower 19 as needed to prevent deformation due to dropping, knock impact, or the like. A tail plug 21 is fixed to the rear end of the ink storage tube 17, and a locking portion 46a of an insertion hole provided at the front end of the sliding pieces 43a, 43b is provided on the shaft at the rear end of the tail plug. , 46b are provided with locking grooves 23 which are detachably fastened. Further, the tail plug 21 is provided with a ventilation groove 22 for communicating the inside of the ink container 17 with the outside air.
The ink storage tube 17 is made of, for example, a transparent PP resin molded product. In addition, the ink storage tube 17 is selected from a material having an excellent clear drain property. Further, the ink storage tube may be formed integrally with the joint 2.
[0025]
Further, the ink storage portion of the ink storage tube 17 is a non-deformed one having a relatively large cross-sectional area, and in the embodiment, has a substantially D-shaped cross-sectional shape that can be inserted into the rear shaft 30 without waste. I have. The portion connecting the tip 11 and the ink storage section can be easily shifted in the lateral direction with respect to the axial direction.
It is also possible to connect a flexible tube between the joint for pressing the rear end of the chip 11 and the ink containing tube.
[0026]
[Action]
When the operating body 40 is advanced to the rear shaft 30 and rotated in one direction, the protrusions 44a and 44b of the sliding pieces 43a and 43b slide along the cam groove 35 with the rotation of the rotating shaft 33. Then, one of the sliding pieces moves forward, and the other slides backward, so that the writing end of the writing body on the advancing side can protrude from the front end of the front shaft 49. At this time, the contact portion 36b of the large-diameter portion 36 contacts the rib 30a to prevent rotation. Even if the ink storage portion of the ballpoint pen writing body is not deformed, the writing tip portion flexibly shifts, so that the operation is not hindered and the writing tip portion protrudes and retracts smoothly from the tip end of the front shaft 49.
[0027]
When the ballpoint pen writing body 1a is in a protruding state, the convex portion 40e of the ball portion 40d of the clip is engaged with the concave portion 39b of the bulging portion 39 of the rear shaft as shown in FIG. Creates a condition that cannot be inserted into a breast pocket or the like.
[0028]
Next, when the rotating shaft 33 is rotated in the opposite direction, the sliding piece 43a is retracted, the writing tip of the ballpoint pen writing body 1a enters the front shaft 49, and the sliding piece 43b moves forward.
At this time, the writing tip is in a portable state accommodated in the front shaft 49, and the clip for that state is in the position shown in FIG. 3 so that it can be easily inserted into a breast pocket or the like. Also, at that time, when the advance of the operating body 40 is released, the rib 30a of the rear shaft is fitted into the vertical groove 36e of the rotating shaft, and the writing body is fixed so as not to move back and forth. In addition, as shown in FIG. 5, the rib 30a can be easily guided to the vertical groove 36e by providing a radius or an appropriate large inclination at the entrance 36f of the vertical groove.
[0029]
When the operating body is moved forward and the rotating shaft 33 is further rotated, the sliding piece 43a is further retracted, the sliding piece 43b is further advanced, and the writing tip of the ballpoint pen writing body 1b is moved to the tip end of the front shaft 49. Project from In this state, the clip is in the position C shown in FIG. 3 and the convex portion 40e of the ball portion 40d of the clip is engaged with the concave portion 39b of the bulging portion 39 of the rear shaft so that the clip 40c cannot be inserted into a breast pocket or the like. create.
Further, the contact portion 36c of the groove 36a of the large-diameter portion 36 of the rotating shaft shown in FIG. 4 abuts on the rib 30a of the rear shaft to regulate the other rotation.
[0030]
When the tip 11 is turned upward, the ball valve 16 is positioned on the ball receiving seat 8 of the valve chamber 7 and seals the guide hole 9 in the ballpoint pen writing body 1a. Even if the ink immediately below 12 runs out, the head does not run over the ink and does not flow backward. Therefore, when the chip 11 is turned downward, the ink can immediately flow out, and the writing is prevented from being rubbed. (By the way, in the structure without the ball valve, the ink acts in the reverse flow direction when writing upwards, so that air is trapped in the chip, and the ink does not follow immediately when writing downwards, resulting in rubbing.)
[0031]
In the writing state in which the tip 11 is directed downward, the ball valve 16 abuts on one of the rear ends of the tip 11 in a biased state, and the other side has a flow path through which ink can flow into the tip 11. The ink 18 that has entered the valve chamber 7 from the housing pipe 17 through the guide hole 9 is guided to the back of the tip ball 12.
In this state, the tip ball 12 is brought into close contact with the inner edge of the tip holding portion by the pressing of the rod shaft portion 15, so that direct current of ink is prevented. In addition, the tip ball 12 is slightly retracted by the writing pressure, so that a gap is generated and ink can flow out. By writing, the rotation of the tip ball 12 allows the ink to flow smoothly, and there is no dent and writing with high handwriting density is possible. It becomes.
[0032]
On the back surface of the tip ball 12, there is a channel (a seat for the tip ball having a plurality of ink inflow grooves penetrating toward the inner hole of the tip), and a rod shaft portion 15 passes through the center hole of the channel. The ink in the chip is guided to the back surface of the tip ball 12 through the ink inflow groove and the gap between the center hole and the rod shaft portion 15.
[0033]
【The invention's effect】
The configuration and operation of the double-type writing instrument of the present invention are as described above. By simplifying the structure, it is advantageous in terms of assemblability and cost, and at the same time, a large ball-point pen which is almost closely packed in the barrel of the writing instrument. A convenient double-type writing instrument loaded with cursive writing can be provided with a shaft thickness that satisfies portability and usability.
In addition, it is equipped with a ballpoint pen writing material using water-based, low-viscosity oil-based ink with so-called shear-thinning, no writing, no drawing lines, no writing scratches, and no need for a cap, and the writing tip is unnecessary. It is possible to appear and disappear, and it is possible to prevent an accident that stains the inside of the shaft cylinder, hands, clothes, and the like due to the direct current of ink, the upward writing, knocking, and the reverse flow of ink with respect to the impact of dropping.
In addition, only when the operating body is rotated and the writing tip protrudes from the tip of the front shaft, the protrusion of the ball portion of the clip is engaged with the recess of the bulging portion of the rear shaft, and the clip is inserted into a breast pocket or the like. Since the writing state is not formed, the writing tip is not inserted into a breast pocket or the like with the projection end protruding, so that an accident that stains clothes is prevented.
Further, in the state where the writing tip is stored, the writing tip does not rotate unless the operating body is pressed and advanced with respect to the rear shaft.
[Brief description of the drawings]
FIG. 1 is a longitudinal cross-sectional view showing the entirety of a double-type writing instrument according to an embodiment of the present invention, and is partially not shown in cross-section. In addition, two kinds of ballpoint pen cursives are mounted.
FIG. 2 is a cross-sectional view taken along a line CC in FIG. 1, but shows a state in which a writing body is not fixed to the sliding piece 43a.
FIG. 3 is a sectional view taken along line BB in FIG. 1; Also, the position of the clip accompanying the rotation of the operating body is shown.
FIG. 4 is a sectional view taken along the line AA in FIG. 1;
FIG. 5 is a perspective view showing a rear end portion of the rotating shaft.
FIG. 6 is a longitudinal sectional view of the ballpoint pen writing body 1a.
FIG. 7 is a cross-sectional view of the ink storage tube.
[Explanation of symbols]
1a Ball-point pen writing body 1b Ball-point writing body 2 Joint 3 Front shaft part 4 Bendable part 5 Rear shaft part 6 Flange part 7 Valve chamber 8 Ball receiving seat 9 Guide hole 10 Inner hole part 11 Chip 12 Tip ball 13 Shaft part 14 Spring 15 Bar shaft part 16 Ball valve 17 Ink storage tube 18 Ink 19 Follower 20 Follower rod 21 Tail plug 22 Vent groove 23 Locking groove 30 Rear shaft 30a Rib 30b Rear end step 31 Guide rib 32 Male screw 33 Rotating shaft 34 Small diameter Portion 35 Cam groove 36 Large diameter portion 36a Groove 36b Contact portion 36c Contact portion 36d Wall portion 36e Vertical groove 36f Inlet 37 Shaft portion 38 Locking portion 38a Shaft portion 38b Flange portion 38c Split groove 38d Detent groove 39 Swelling portion 39a convex portion 39b concave portion 40 operating body 40a cylindrical portion 40b rear end portion 40c clip 40d ball portion 40e convex portion 40f concave portion 41 spring 42 crown 43a Sliding piece 43b Sliding piece 44a Projection 44b Projection 45a Insertion hole 45b Insertion hole 46a Locking portion 46b Locking portion 47a Guide groove 47b Guide protrusion 48a Groove 48b Groove 49 Front shaft 49a Female screw 50 Tip opening

Claims (5)

In a dual-type writing instrument equipped with two types of ballpoint pen writing elements, each writing tip of which can be selectively protruded and retracted alternately from the tip opening of the front axis, a front axis, a rear axis, and a rear axis An operating body fixed to the rear end of the rotary shaft protruding from the rear end of the rear shaft, and a cam groove is formed on the shaft peripheral surface. A pair of sliding pieces are formed on the outer periphery of the rotating shaft, the protrusions engaging with the cam grooves being formed on the inside facing each other, and a ballpoint pen writing body is provided in front of each sliding piece. A circumferential groove cut out at the rear end side of the large-diameter portion peripheral surface located behind the cam groove of the rotary shaft, a narrow vertical groove cut out at the front end at the center of the groove, and a rear shaft. rear inside rib is formed on the circumference of, and the rotation shaft forward as appropriate with the operating body a spring is provided between the rear end of the rear axle and the operating body In performance, the and biased rearward in a state where the rotary shaft is retained in the rear shaft rear end, when rotating the operation member with respect to the rear axle, the rib of the rear axle is a circumferential groove of the rotary shaft The rear shaft slides in the rotation direction within the range of approximately 180 degrees, and the ribs of the rear shaft are fitted and engaged with the narrow vertical grooves of the rotation shaft. When the operating body is appropriately advanced with respect to the shaft and rotated in a state where the rib of the rear shaft and the narrow vertical groove of the rotating shaft are released , the rotating shaft becomes rotatable, and the rotating shaft accompanying the rotation of the operating body is rotated. A double writing implement characterized in that each sliding piece is moved back and forth alternately in conjunction with the rotation of, so that the writing tip of each writing body can protrude and retract from the tip end of the front shaft. The ballpoint pen writing body has a so-called shear thinning viscosity, which has a tip holding the tip ball and an ink storage tube in the back, and the viscosity decreases due to the rotation of the tip ball accompanying the writing and flows out into the ink storage tube. Water-based ballpoint pen ink or low-viscosity oil-based ink, and the back end of the ink is filled with a grease-like translucent non-drying follower that moves following the consumption of ink during writing. Wherein the ink storage portion of the ink storage tube is a non-deformed one having a relatively large cross-sectional area, and a portion connecting the tip and the ink storage portion can be easily shifted in a lateral direction with respect to the axial direction. 2. The double-type writing instrument according to claim 1, wherein: 3. The ballpoint pen writing body according to claim 2, further comprising a spring provided so that the tip ball always presses and contacts the inner edge of the ball holding portion at the tip of the tip, and the contact state is released during writing. Double writing instrument. The ballpoint pen writing body is provided with a valve chamber in which a ball valve is loosely fitted in contact with the rear end of the chip. The ball valve is closely attached to the rear of the valve chamber to prevent a backflow of ink. 4. The dual writing implement according to claim 3 , wherein a guide hole communicating with the ink storage tube is provided. A clip provided from one side of the operating body toward the front of the rear shaft, and a bulging portion is provided at a predetermined position on the rear shaft peripheral surface which is in contact with a ball portion of the clip, and the operating body is rotated for writing. The above-mentioned claim , characterized in that the clip is not inserted into a breast pocket or the like by engagement between the ball portion of the clip and the bulging portion only in a state where the tip portion protrudes from the tip end of the tip shaft. Item 5. The dual-purpose writing instrument according to any one of Items 2 to 4 .

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