JP2018138376A - Ball point pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ballpoint pen which reduces the load on the caulked portion and prevents damage or deformation of the caulked portion.SOLUTION: There is provided a ballpoint pen having a protruding and retracting mechanism capable of allowing a ballpoint pen tip 12 to protrude and retract from a front end opening portion 2b of a barrel 4, the ball point pen operating a pressurizing mechanism 23 provided in the barrel 4 to apply pressure to the rear end of a writing instrument ink composition 10. The ballpoint pen has a protection cover 15 disposed so as to cover a caulked portion 13g on the outside of the ballpoint pen tip 12, in which a front portion 15b of the protection cover 15 is located forward of the caulked portion 13g, and an extended portion 15d located behind a front end opening portion 2b of the barrel 4 is formed in the rear portion of the protection cover 15 with the front end of the ball point pen refill 12 projecting forward from the front end opening portion 2b of the barrel 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a ballpoint pen having a protective cover disposed outside a ballpoint pen tip so as to cover a caulking portion.

  Conventionally, a ballpoint pen having a protective cover disposed so as to cover the crimping portion outside the ballpoint pen tip, for example, as disclosed in Japanese Patent Application Laid-Open No. 2013-252654 “Ballpoint pen”, an outer covering the outer periphery of the holder has been provided. Ballpoint pens are known.

JP 2013-252654 A

According to Patent Document 1, the writing ball body and the outer tip are brought into contact with the writing surface at the time of writing, and ink is diffused by a capillary phenomenon in a portion surrounded by the writing surface, the outer and the writing ball body at the time of writing. Can be thickened.
On the other hand, in a general ballpoint pen, the crimping portion formed to prevent the writing ball body at the front end of the ballpoint pen tip from falling off has an impact force when the writing ball body comes into contact with the writing surface at the start of writing, Or the vibration of the writing ball due to the unevenness of the writing surface, and further the pressing force by pressing the writing ball forward from the back with a spring or the like to prevent ink leakage when using ink with low viscosity In some cases, ink leakage may occur from the front end of the chip due to breakage or deformation of the caulking portion. In particular, in a retractable ballpoint pen, it is necessary to protrude and retract the ballpoint pen tip from the shaft tube, and a minimum clearance is required between the ballpoint pen tip and the shaft tube. By being shaken in the axial direction by the writing pressure, there is a tendency that the load applied to the caulking portion becomes larger and the caulking portion is more likely to be damaged or deformed. Further, such damage and deformation of the caulking portion tend to occur near the front end of the caulking portion.

  However, since the structure of Patent Document 1 requires a space in which ink is accumulated between the outer and the writing ball body, the entire crimped portion cannot be protected, and the above problem cannot be solved. It was.

  The present invention was invented to solve these problems, and an object of the present invention is to provide a ballpoint pen that reduces the load on the caulking portion and prevents breakage and deformation of the caulking portion.

The present invention
“1. A ball pen refill comprising an ink container filled with an ink composition for a writing instrument in a shaft cylinder, a ballpoint pen tip on the front part of the ink container, and the ball pen tip is opened at the front end of the shaft cylinder A ballpoint pen having an in / out mechanism capable of intruding from a section,
The ball-point pen tip is formed into a cylindrical tip body, a writing ball body that is partly protruded from a front end opening of the chip body and rotatably arranged, and the writing ball body is attached to the tip body. A caulking portion that holds the front end opening so as not to fall out, and a bottom wall that supports the writing ball body when the writing ball body abuts at the time of writing;
On the outside of the ballpoint pen tip, it has a protective cover arranged so as to cover the caulking part,
The front end portion of the protective cover is located in front of the front end portion of the caulking portion,
An extension portion is formed at the rear portion of the protective cover, with the front end of the ballpoint pen refill projecting forward from the front end opening of the shaft tube, and positioned behind the front end opening of the shaft tube. A characteristic ballpoint pen.
2. The item 1, wherein a minimum inner diameter of a front end portion of the protective cover is formed smaller than a minimum inner diameter of a front end portion of the crimping portion, and the crimping portion does not contact the writing surface during writing. Ballpoint pen as described in
3. 3. The ballpoint pen according to item 1 or 2, wherein a vibration absorbing portion that absorbs vibration during writing of the ballpoint pen tip is provided between the protective cover and the tip body.
4). 4. The ballpoint pen according to any one of claims 1 to 3, wherein the protective cover is detachably attached to the ballpoint pen tip. Is.
In the present invention, “front” refers to the ballpoint tip side of the ballpoint refill, and “rearward” refers to the opposite side. Further, “inward” refers to the direction from the outer periphery of the shaft tube toward the axial center, and “outward” refers to the opposite direction.

According to the present invention, the ballpoint pen tip has the protective cover disposed so as to cover the caulking portion, and the front end portion of the protective cover is positioned in front of the front end portion of the caulking portion. The caulking portion formed at the front end of the chip does not contact the writing surface, and the caulking portion is protected, thereby reducing the load applied to the caulking portion. For this reason, it is possible to prevent ink leakage caused by breakage or deformation of the caulking portion, falling off of the writing ball body, and deterioration of writing feeling due to abnormal rotation of the writing ball body. Further, since the caulking portion is not exposed to the outside by the protective cover in the longitudinal direction of the ballpoint pen tip, it is possible to suppress the caulking portion from being damaged regardless of writing or non-writing.
In addition, when writing with the ballpoint pen of the present invention, the rear end of the protective cover has a front end of the ballpoint pen refill projecting forward from the front end opening of the shaft tube and extending behind the front end opening of the shaft tube. By forming the protruding portion, it is preferable that the extending portion of the protective cover and the inner side surface of the shaft cylinder are configured to contact or be able to contact at the time of writing. In this case, even if the ball pen refill vibrates due to the unevenness of the writing surface during writing, the vibration of the ball pen refill is reduced by the protective cover due to the contact between the extended portion of the protective cover and the inner surface of the shaft tube, and the caulking portion As a result, the load on the finger is reduced and vibration is prevented from being transmitted to the finger holding the shaft tube, and a good writing feeling can be obtained.

In addition, the protective cover preferably has a surface roughness (average surface roughness Ra) of 6.3 μm or less, and 1.6 μm or less so that the writing feeling does not decrease even if it contacts the writing surface during writing. More preferably.
Further, the front end portion of the protective cover is formed in a curved shape protruding forward (outward) so as to be slippery when coming into contact with the writing surface, so that the contact area with the writing surface is reduced. Is preferred.

Further, the protective cover preferably has a vibration absorbing property so that the vibration of the ball-point pen tip during writing can be reduced when the extended portion of the protective cover comes into contact with the inner surface of the shaft cylinder. It is preferable to have wear resistance so that it does not wear even when it comes into contact.
The material used for the protective cover is not particularly limited. For example, a hard resin material such as PP resin or PC resin, a metal material, or a material having rubber elasticity such as rubber or elastomer is used. Can do.

In addition, when a material having rubber elasticity such as rubber or elastomer is used for the protective cover, since the material having rubber elasticity has high vibration absorption, the front end of the ball-point pen tip comes into contact with the writing surface at the start of writing. It is possible to reduce the load applied to the caulking portion of the ball-point pen tip due to the impact caused by the vibration and the vibration generated by the unevenness of the writing surface.
The rubber-elastic material includes natural rubber, urethane rubber, silicone rubber, fluorine rubber, butyl rubber, ethylene / propylene rubber, isopropylene rubber, butadiene rubber, styrene elastomer, olefin elastomer, urethane elastomer, and the like. Further, the sliding performance may be improved by forming a resin film on the surface of the protective cover so as to improve the wear resistance.

Furthermore, when a metal material is used for the protective cover, since the metal material has high wear resistance, it is prevented from being worn even if the protective cover contacts the writing surface during writing. Since the metal material also has a high hardness, the load from the inside and outside applied to the caulking portion can be reduced by the protective cover.
When the protective cover is formed of a metal material, brass or aluminum can be suitably used in terms of machinability, and the surface may be subjected to a lubricious surface treatment in order to improve lubricity and durability. . The lubricating surface treatment can be selected from, for example, electroless nickel plating, tin-cobalt plating, or an oxide film treatment with alumite.

Further, when a hard resin material is used for the protective cover, the resin material has an appropriate elasticity and hardness, which is preferable because it can exhibit both vibration absorption and wear resistance in a balanced manner.
The resin material can be selected from PP resin, PC resin, PMMA resin, POM resin, ABS resin, etc. Further, a lubricating component is added so that the contact resistance with the writing surface is reduced and the lubricity is improved. It may be contained in the material.

Here, in the ballpoint pen of the present invention, if the ballpoint pen refill can be projected and retracted from the front end of the shaft cylinder, the projecting and retracting mechanism is not particularly limited, such as a knocking type and a rotation feeding type.
In addition, with a pressurized ballpoint pen that applies higher pressure to the ink than a normal ballpoint pen, additional pressure is applied to the crimped portion due to the pressure of the ink, increasing the risk of ink leakage from the front end of the ballpoint pen tip. Therefore, the structure of the present invention can be preferably used.
Furthermore, when the present invention is used for a pressure ballpoint pen, the pressure system for operating the pressure mechanism is not particularly limited, and the ballpoint pen refill is moved backward by the writing pressure at the time of writing. It may be operated and a writing pressure pressurizing type that applies pressure to the trailing end of the writing instrument ink composition only at the time of writing may be adopted. The pressing mechanism is operated by pressing the knock body, and the writing ink composition is always used. You may employ | adopt the knock pressurization type which applies a pressure to the rear end. In addition, when the pressure-pressing type is used, no pressure is applied to the rear end of the ink composition for writing instruments except during writing (when storing or carrying), preventing ink leakage from the front end of the ballpoint pen tip. can do.

  Further, by forming the minimum inner diameter of the front end portion of the protective cover smaller than the minimum inner diameter of the front end portion of the caulking portion, even if the writing surface has irregularities, the caulking portion does not contact the writing surface, Since the caulking portion can be reliably protected, the load on the caulking portion is reduced, and the caulking portion can be prevented from being damaged or deformed.

Furthermore, when the protective cover is formed of a metal material or a resin material, a hollow portion is provided between the chip body and the protective cover or an elastic body having rubber elasticity is inserted so as to improve vibration absorption. Thus, it is preferable to form a vibration absorbing portion that absorbs vibration.
The position of the vibration absorbing portion is not particularly limited as long as it is formed between the chip body and the protective cover. For example, the vibration absorbing section may be formed between the chip body and the protective cover in the axial radial direction. It may be formed between the directions along the axis, or between both the axial direction and the direction along the axis. Furthermore, the vibration absorbing portion may be formed integrally with the protective cover or may be formed integrally with the chip body.

  In addition, there is a possibility that the ballpoint pen refill can be used by adjusting the thickness of the protective cover even if there is a difference in the inner diameter of the front end opening of the shaft cylinder by detachably attaching the protective cover to the ballpoint pen tip. This is preferable because it saves time and effort to design and manufacture ballpoint pen tips according to individual specifications.

  ADVANTAGE OF THE INVENTION According to this invention, the ball-point pen which reduced the load to a crimping part and prevented the damage and deformation | transformation of the said crimping part could be provided.

1 is a longitudinal sectional view of a ballpoint pen of Example 1. FIG. FIG. 2 is an enlarged longitudinal sectional view of a ballpoint pen tip of the ballpoint pen of FIG. 1. FIG. 3 is an enlarged longitudinal sectional view showing a front end of the ballpoint pen tip of FIG. 2. FIG. 4 is an enlarged longitudinal sectional view showing a front end of the ballpoint pen tip of FIG. 3. FIG. 2 is an enlarged vertical sectional view of a pressure mechanism of the ballpoint pen of FIG. 1. FIG. 2 is a longitudinal sectional view of the ballpoint pen of FIG. 1 in a state where a ballpoint pen refill is projected forward from the front end of the shaft cylinder. FIG. 7 is a longitudinal sectional view showing a state where no writing pressure is applied to the ballpoint refill in the ballpoint pen of FIG. 6. FIG. 7 is a longitudinal sectional view showing a state in which writing pressure is applied to the ballpoint pen refill in the ballpoint pen of FIG. 6. FIG. 9 is an enlarged longitudinal sectional view showing the front end of the ballpoint pen tip in the state of FIG. 8.

  Next, although the ball-point pen of this invention is demonstrated in detail, referring drawings, this invention is not limited to a following example.

Example 1
1 is a schematic longitudinal sectional view of the ballpoint pen 1 of the present embodiment, FIG. 2 is a schematic enlarged longitudinal sectional view of the ballpoint pen tip 12 of the ballpoint pen 1 of FIG. 1, and FIG. 3 is a perspective view of the ballpoint pen tip 12 of FIG. 4 is a schematic enlarged longitudinal sectional view of the front end of FIG. 4, FIG. 4 is a schematic enlarged longitudinal sectional view of the front end of the ballpoint pen tip 12 of FIG. 3, and FIG. 5 is a schematic enlarged longitudinal sectional view of the pressure mechanism 6 of FIG. 6 is a longitudinal sectional view of the ballpoint pen 1 of FIG. 1 in which the ballpoint pen refill 7 protrudes forward from the front end of the shaft cylinder 2. FIG. 7 is a perspective view of the ballpoint pen 1 of FIG. FIG. 8 is a longitudinal sectional view showing a state in which the writing surface 100 is brought into contact, FIG. 8 is a longitudinal sectional view showing a state in which writing pressure is applied to the ballpoint pen refill 7 in FIG. 7, and FIG. 9 is a diagram of the ballpoint pen tip 12 in FIG. Front enlarged It is a surface view.

The ballpoint pen 1 of this embodiment is a pen pressure type ballpoint pen. As shown in FIGS. 1 to 6, the front shaft 2 and the rear shaft 3 constitute a shaft cylinder 4, and the front shaft 2 has a rear outer surface. A male screw portion 2a is provided, and is detachably screwed to a female screw portion 3a provided on the inner surface of the front portion of the rear shaft 3. Furthermore, the ball-point pen 1 is accommodated so as to be able to appear and retract by an opaque grip 5 formed so as to surround the outer surface of the front shaft 2 in the axial circumferential direction and a rotating cam mechanism 6 (an appearance mechanism) provided in the shaft cylinder 4. A ballpoint pen refill 7. A rear end inner peripheral portion 7 a of the ballpoint pen refill 7 is detachably press-fitted to a front end outer peripheral portion 8 a of a cylinder 8 disposed in the shaft cylinder 4. Further, the front shaft 2 is formed with a front end opening 2b at the front end from which the ballpoint pen tip 12 of the ballpoint pen refill 7 can protrude.
The grip 5 is made of a styrene elastomer and is provided integrally with the front shaft 2 by two-color molding.

  The ballpoint pen refill 7 has a writing ink composition 10 and a grease-like ink follower 11 that follows the ink consumption 10 behind the writing instrument ink composition 10 in a transparent ink containing cylinder 9 made of PP resin. This is obtained by directly fitting and fitting the rear end portion of the ball-point pen tip 12 holding the writing ball body 14 rotatably into the front end opening of the ink containing cylinder 9.

  The ball-point pen tip 12 will be described in detail. As shown in FIG. 2 to FIG. 4, the ball-point pen tip 12 includes a tip body 13 made of stainless steel wire, a ball holding chamber 13a (front end opening), and a ball holding chamber 13a. Are formed in the center of the ink flow hole 13b and an ink flow groove 13d that extends radially to the ink flow hole 13b and does not reach the tip rear hole 13c, and the bottom wall 13e of the ball holding chamber 13a has φ0. A caulking portion 13g is formed by placing a writing ball body 14 made of 38 mm cemented carbide and caulking the front end portion 13f inward.

  In addition, the ball-point pen tip 12 is specifically formed by cutting a stainless steel wire having a diameter of 2.3 mm and a hardness of 230 Hv to 280 Hv by cutting the ball holding chamber 13a, the ink circulation groove 13d, the ink circulation hole 13b, and the chip rear hole 13c. After that, the writing ball body 14 is placed on the bottom wall 13e of the ball holding chamber 13a, and a ball seat having substantially the same shape as the writing ball body 14 is placed on the bottom wall 13e of the ball holding chamber 13a by hammering. Is formed.

  Further, a cylindrical protective cover 15 is detachably press-fitted to the outer peripheral portion of the chip body 13, and the angle of the front inner step portion 15a formed on the inner surface of the protective cover 15 is set to the caulking portion 13g. By adjusting the angle, the caulking portion 13g is covered with the protective cover 15 in contact with the front inner step portion 15a, and the caulking portion 13g is deformed regardless of whether the force is applied to the caulking portion 13g from the front or the rear. Is prevented.

The protective cover 15 will be described in more detail. The front portion 15b of the protective cover 15 is formed in a curved shape protruding forward (outward) as shown in FIGS. 2 to 4, and the protective cover 15 is written during writing. Even if the front portion 15b of the head is in contact with the writing surface, it is not caught on the writing surface, and it can be moved smoothly by forming the surface roughness small.
Further, the extending portion 15d on the rear outer surface of the protective cover 15 extends to the rear side from the front end opening portion 2b in a state where the front portion 15b is extended forward from the front end opening portion 2b of the front shaft 2 by a knocking operation described later. And is configured to be able to come into contact with the front end opening 2b (the inner surface of the shaft tube 4).
Furthermore, a cavity 24 is formed as a vibration absorbing portion between the inner surface of the protective cover 15 and the side surface of the chip body 13, and even if vibration occurs in the ballpoint pen tip 12 due to unevenness of the writing surface during writing, Since the cavity portion 24 absorbs vibration by the extension portion 15d of the protective cover 15 coming into contact with the front end opening portion 2b of the front shaft 2 (the inner surface of the shaft tube 4), the load applied to the caulking portion 13g of the ballpoint pen tip 12 And also reduces the transmission of vibrations to the finger holding the shaft cylinder 4, thereby improving the writing feeling.

  Specifically, the protective cover 15 is formed by injection molding of POM resin, and the surface roughness (arithmetic average roughness Ra) of the front portion 15b of the protective cover 15 is 0.8 μm or less. It is.

  2 to 4, the front end portion 15c of the front portion 15b of the protective cover 15 is positioned in front of the front end portion 13g1 of the crimping portion 13g of the chip body 13, and the front end portion 13g1 of the crimping portion 13g. By forming the minimum inner diameter D2 of the front end 15c of the protective cover 15 smaller than the minimum inner diameter D1, the caulking 13g is hidden by the protective cover 15 when the ball-point pen tip 12 is viewed from the front side. Thereby, even if there is unevenness on the writing surface, the crimping portion 13g is prevented from coming into contact with the writing surface during writing, and the load on the crimping portion 13g is reduced.

  Further, as shown in FIG. 1, a coil spring 16 (first elastic member) is stretched between the front step portion 7 b of the ballpoint pen refill 7 and the inner step 2 c of the front shaft 2, The ballpoint pen refill 7 is repelled axially rearward.

The rotating cam mechanism 6 (in / out mechanism) is provided in the rear shaft 3 with a rotating cam 17 for switching in / out of the ball-point pen tip 12 of the ballpoint pen refill 7 and a cam groove 3b that engages with the rotating cam 17. . When the knock member 18 is pushed forward (knock operation) with the ball pen tip 12 of the ball pen refill 7 immersed in the front shaft 2 (see FIG. 1), the rotating cam 17 moves along the cam groove 3b. The ballpoint pen tip 12 of the ballpoint pen refill 7 slid forward and pushed by the rotary cam 17 is projected forward from the front end opening 2 b of the front shaft 2, and the rotary cam mechanism 6 further rotates the rotary cam 17. As a result, the rotating cam 17 is in contact with the inner stage of the rear shaft 3 and is not allowed to move rearward in the axial direction, and the protruding state of the ballpoint pen tip 12 is maintained even after the pressing operation is completed. Become.
Further, when the knock member 18 is again pushed forward (knock operation) with the ball-point pen tip 12 in FIG. 6 protruding, relative rotation of the rotary cam 17 in the axial rearward direction is allowed by the action of the rotary cam mechanism 6. The ball pen refill 7 and the knock member 18 are pushed back in the axial direction by the resilient force of the coil spring 16 to return to the initial state (the state shown in FIG. 1).

  Next, as shown in FIGS. 1 and 5, a piston 19 is disposed in front of the rotating cam 17. The piston 19 has a flange portion 19 b provided at the rear end portion 19 a in contact with the front end 17 a of the rotary cam 17, and the front portion 19 c is slidably inserted into the rear end opening portion 8 b of the cylinder 8. The front portion 19c of the piston 19 is formed with a smaller diameter than the flange portion 19b of the rear end portion 19a.

The piston 19 will be described in more detail. The piston 19 is a cylindrical body having an inner hole whose front end is closed. On the side surface of the piston 19, a projecting portion 19d that protrudes outward is symmetrically sandwiched between two axes. The protrusions 19d are slidably latched on window portions 8d extending along the axial center formed on the rear outer peripheral portion 8c of the cylinder 8.
Further, a groove-like groove portion 19e extending in the axial circumferential direction is formed on the side surface of the front portion 19c of the piston 19, and an O-ring 20 made of synthetic rubber is fitted into the groove portion 19e. The outer portion of the O-ring 20 is in sliding contact with the inner portion 8f of the cylinder 8, and the rear end opening 8b of the cylinder 8 is sealed by the piston 19 and the O-ring 20 so that air does not leak.

The cylinder 8 will be described in more detail. The cylinder 8 is a cylinder having an inner hole 8i formed therein, and an air hole 8e penetrating to the inner hole 8i is formed in the rear outer peripheral portion 8c of the cylinder 8. In addition, a pressurizing chamber 21 surrounded by the inner portion 8f of the cylinder 8, the front end of the piston 19, and the O-ring 20 is formed in the inner hole 8i of the cylinder 8, and the pressurizing chamber 21 is formed by the air hole 8e. Aerated with the outside.
Further, the front end outer peripheral portion 8a of the cylinder 8 is formed with a smaller diameter than the rear outer peripheral portion 8c, and the front end outer peripheral portion 8a has two mounting portions 8g protruding circumferentially outward. Further, as described above, the rear end inner peripheral portion 7a of the ballpoint pen refill 7 is detachably press-fitted to the mounting portion 8g of the front end outer peripheral portion 8a of the cylinder 8, so that the pressurizing chamber 21 has the inner hole 8i of the cylinder 8. As a result, the ball pen refill 7 communicates with the rear inner hole 7c.
For this reason, the pressurizing chamber 21 is in a sealed state when the position of the O-ring 20 is in front of the air hole 8e of the cylinder 8 by sliding back and forth of the cylinder 8, and the position of the O-ring 20 is from the air hole 8e. When in the rear, the pressurizing chamber 21 and the outside of the cylinder are ventilated by the air holes 8e and are not sealed.

Further, a pressure coil spring 22 (second elastic member) is stretched between the inner stage 8 h of the cylinder 8 and the front stage part 19 f of the piston 19, so that the cylinder 8 is moved forward with respect to the piston 19. It ’s bulleted.
The spring force of the pressurizing coil spring 22 (second spring member) is set to be larger than the spring force of the coil spring 16 (first spring member). The rearward movement is prevented and the pressurizing chamber 21 is not pressurized.

  Further, the outer diameter (maximum diameter) of the rear outer peripheral portion 8 c of the cylinder 8 and the outer diameter (maximum diameter) of the flange portion 19 b of the piston 19 are substantially the same as the outer diameter (maximum diameter) of the ink containing cylinder 9 of the ballpoint refill 7. It is formed with.

  In this embodiment, the cylinder 8, the piston 19, the O-ring 20, the pressurizing chamber 21, and the pressurizing coil spring 22 constitute a pressurizing mechanism 23.

Next, the writing operation of the ballpoint pen 1 of the present embodiment will be described with reference to FIGS.
As shown in FIG. 7, when writing, the shaft tube 2 is generally gripped so as to form an acute angle with respect to the axis. Then, when the knocking member 18 is pressed forward (knocking operation) and the writing pressure applied by the writing is applied to the ball-point pen tip 12 with the front end of the ball-point pen tip 12 protruding from the front-end opening 2b of the front shaft 2, as described above. As described above, since the rotary cam 17 and the piston 19 in contact with the front end 17a of the rotary cam 17 cannot move backward, the ball-point refill 7 and the cylinder 8 are interlocked against the resilient force of the pressurizing coil spring 22. Then, it moves backward (in the direction of arrow G) along the axis.

Specifically, first, when the pressurizing coil spring 22 is compressed and the cylinder 8 is moved rearward, the air hole 8e of the cylinder 8 is moved rearward from the position of the O-ring 20 so that the inner portion 8f of the cylinder 8 has O. Since the ring 20 is in sliding contact, the pressurizing chamber 21 is sealed. Further, when the cylinder 8 moves rearward, the pressurizing coil spring 22 is further compressed, the pressurizing chamber 21 communicating with the rear inner hole 7c of the ballpoint pen refill 7 is compressed, and the writing ink composition 10 in the ballpoint pen refill 7 is compressed. Then, the ink follower 11 is in a state shown in FIG.
The retreat of the cylinder 8 is stopped by the rear end of the cylinder 8 coming into contact with the front end of the flange 19b of the piston 19, and the pressurizing chamber 21 is prevented from being pressurized more than necessary.

  Here, when the writing pressure is released from the state of FIG. 8, the cylinder 8 and the ballpoint pen refill 7 move forward (original position) by the elastic force of the pressurizing coil spring 22. At that time, when the position of the air hole 8e of the cylinder 8 reaches the O-ring 20, the air hole 8e is opened and the sealing of the pressurizing chamber 21 and the rear inner hole 7c of the ballpoint pen refill 7 is released to the same pressure as the atmospheric pressure. And return to the state of FIG. In this example, the maximum pressure applied to the rear end of the writing instrument ink composition 10 via the ink follower 11 during writing was 1050 hPa.

When writing, in this embodiment, the ball pen refill 7 is retracted to pressurize the writing instrument ink composition 10, so that the front end of the ballpoint pen tip 12 has a higher writing pressure than the non-pressurized ballpoint pen. It takes. Further, in this state, when the crimped portion 13g of the ballpoint pen tip 12 comes into contact with the writing surface 100, the writing feeling is remarkably reduced, and the load on the crimped portion 13g is increased, and the crimped portion 13g may be deformed or damaged. However, in this embodiment, as shown in FIGS. 4 and 9, the outer periphery of the tip body 13 of the ball-point pen tip 12 is covered with the protective cover 15, and the front end portion 15c of the protective cover 15 is more than the front end portion 13g1 of the caulking portion 13g. Further, since the minimum inner diameter D2 of the front end portion 15c of the protective cover 15 is smaller than the minimum inner diameter D1 of the front end portion 13g1 of the caulking portion 13g, the caulking portion 13g is in contact with the writing surface 100. In addition, the surface of the front portion 15b of the protective cover 15 is curved, and as described above, the surface roughness is reduced so as to be slippery. Be protected as 9 cover by tilting the heart is in contact with the writing surface 100 to reduce the deterioration of the writing feel, it was possible to continue the good writing feeling.
Since the cavity 24 is formed between the chip body 13 and the protective cover 15 as described above, even if the ball-point pen tip 12 vibrates due to minute irregularities on the writing surface 100 during writing, the protective cover is provided. 15 abuts 15 d and the front end opening 2 b of the front shaft 2 (inner side surface of the shaft tube 4) so that the cavity 24 functions as a cushion and transmits the vibration of the ball-point pen tip 12 to the shaft tube 4. As a result, the writing feeling is improved and the vibration of the ball pen tip 12 itself is also absorbed, so that an effect of reducing the load applied to the caulking portion 13g of the tip body 13 is also obtained.

  Furthermore, in general, pressure is applied to the pressure ballpoint pen during writing, and pressure is applied to the caulking portion of the ballpoint pen tip through the ink from the rear, which promotes damage and deformation of the caulking portion in the long term. Although there is a risk that writing feeling, ink leakage, dropping of the writing ball, etc. may occur, in this embodiment, the caulking portion 13g and the front inner step portion 15a of the protective cover 15 are in contact with each other. Therefore, the caulking portion 13g is supported by the protective cover 15, and the occurrence of breakage or deformation of the caulking portion 13g can be reduced.

  In the present embodiment, for the sake of convenience, a mechanism for causing the tip front end portion to protrude from the front end opening portion of the shaft cylinder by a rear end knocking operation is illustrated, but the appearance mechanism such as knock type, slide type, rotation, etc. is particularly limited. is not. Further, it is sufficient that at least one ballpoint pen refill is accommodated in the shaft cylinder. For example, a configuration in which a plurality of ballpoint pen refills are accommodated in the shaft cylinder may be employed.

1 ... ballpoint pen,
2 ... front shaft, 2a ... male screw part, 2b ... front end opening, 2c ... inner stage,
3 ... rear shaft, 3a ... female screw part, 3b ... cam groove,
4 ... shaft tube,
5 ... grips,
6 ... Rotating cam mechanism (in / out mechanism),
7 ... Ball pen refill, 7a ... Rear end inner periphery, 7b ... Front step, 7c ... Rear inner hole 8 ... Cylinder, 8a ... Front end outer periphery, 8b ... Rear end opening, 8c ... Rear outer periphery,
8d ... window part, 8e ... air hole, 8f ... inner part, 8g ... mounting part, 8h ... inner stage, 8i ... inner hole,
9: Ink storage cylinder,
10: Ink composition for writing instruments,
11 ... ink follower,
12 ... ballpoint pen tip,
13 ... Chip body, 13a ... Ball holding chamber (front end opening), 13b ... Ink flow hole,
13c: chip rear hole, 13d: ink circulation groove, 13e: bottom wall, 13f: front end,
13g ... caulking part, 13g1 ... front end part,
14 ... writing ball,
15 ... Protective cover, 15a ... Front inner step part, 15b ... Front part, 15c ... Front end part,
15d ... extension part,
16: Coil spring (first elastic member),
17 ... Rotating cam, 17a ... Front end,
18 ... knock member,
19 ... piston, 19a ... rear end, 19b ... collar, 19c ... front, 19d ... projection,
19e ... groove, 19f ... front stage,
20 ... O-ring,
21 ... Pressure chamber,
22 ... Coil spring for pressurization (second elastic member),
23 ... Pressure mechanism,
24 ... hollow part (vibration absorbing part),
100 ... Writing surface.

Claims (4)

A ball pen refill comprising an ink container filled with an ink composition for a writing instrument, a ballpoint pen tip on the front part of the ink container, and the ball pen chip protruding from a front end opening of the shaft cylinder. A ballpoint pen having a possible infestation mechanism,
The ball-point pen tip is formed into a cylindrical tip body, a writing ball body that is partly protruded from a front end opening of the chip body and rotatably arranged, and the writing ball body is attached to the tip body. A caulking portion that holds the front end opening so as not to fall out, and a bottom wall that supports the writing ball body when the writing ball body abuts at the time of writing;
On the outside of the ballpoint pen tip, it has a protective cover arranged so as to cover the caulking part,
The front end portion of the protective cover is located in front of the front end portion of the caulking portion,
An extension portion is formed at the rear portion of the protective cover, with the front end of the ballpoint pen refill projecting forward from the front end opening of the shaft tube, and positioned behind the front end opening of the shaft tube. A characteristic ballpoint pen.   The minimum inner diameter of the front end portion of the protective cover is smaller than the minimum inner diameter of the front end portion of the crimping portion, and the crimping portion is configured not to contact the writing surface during writing. Ballpoint pen as described in   3. The ballpoint pen according to claim 1, wherein a vibration absorbing portion that absorbs vibration during writing of the ballpoint pen tip is provided between the protective cover and the tip body.   The ballpoint pen according to any one of claims 1 to 3, wherein the protective cover is detachably attached to the ballpoint pen tip.

Images