Writing instrument

Abstract

To provide a writing instrument capable of maintaining an effect of suppressing backlash in a barrel of a writing body and unnecessary for a user to remove an annular member in replacing the writing body, thereby preventing the annular member from being lost.SOLUTION: The writing instrument includes a barrel having an opening at a front end, a writing body stored in the barrel, and an annular member mounted on an inner surface of the barrel. The writing body includes a pen point and an ink reservoir storing an ink in its inside. The barrel comprises at least a front shaft including an opening from which the pen point is protruded, and a rear shaft detachably screwed into the front shaft. The annular member is mounted at a rear part of the front shaft, and the writing body is loosely inserted into the annular member.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a writing instrument. More specifically, the present invention relates to a writing instrument in which a writing body is housed in a shaft cylinder of the writing instrument.

Background Art

[0002] Patent Document 1 discloses a writing instrument including a shaft cylinder, a refill that can be housed in the shaft cylinder, a support member assembled between the shaft cylinder and the refill, and a return spring disposed behind the support member and biasing the refill rearward. The support member is assembled at a predetermined position in the front-rear direction such that when the front portion of the refill cantilever-supported by the support member vibrates due to a predetermined external force, the front portion of the refill does not collide with the inner peripheral surface or the tip opening of the shaft cylinder.

[0003] According to the writing instrument, the impact on the refill applied from the outside can be reduced more than before.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the configuration disclosed in Patent Document 1, the support member (corresponding to the annular member in the present application) can be attached to the refill (corresponding to the writing body in the present application) from the side (radial direction), and the attachment position in the axial direction thereof can be adjusted. That is, the user can easily adjust the arrangement position of the support member in the axial direction thereof. For this reason, during use of the writing instrument or the like, the support member may move unexpectedly in the front-rear direction, and it may be difficult to maintain the desired effect of reducing the impact on the refill.

[0006] In addition, in the configuration disclosed in Patent Document 1, the support member can be easily assembled to the refill, and even when the refill is replaced, the support member can be easily reassembled. Therefore, when replacing the refill, the user needs to remove the support member, and at that time, there is a risk of losing the support member.

[0007] The present invention has been made in view of the above findings, and an object thereof is to prevent the annular member from unexpectedly moving in the front-rear direction, maintain the effect of suppressing rattling in the shaft cylinder of the writing body, and prevent the user from having to remove the annular member when replacing the writing body, thereby providing a writing instrument that can prevent the loss of the annular member.

Means for Solving the Problems

[0008] The writing instrument of the present invention includes a shaft cylinder having an opening at the front end, a writing body accommodated in the shaft cylinder, and an annular member attached to the inner surface of the shaft cylinder. The writing body includes a pen tip and an ink storage tube that stores ink therein. The shaft cylinder includes at least a front shaft having the opening through which the pen tip protrudes, and a rear shaft that is detachably screwed to the front shaft. The annular member is attached to the rear part of the front shaft, and the writing body is provided so as to pass through the annular member loosely.

[0009] According to the present invention, since the annular member is attached to the rear part of the front shaft and the writing body is provided so as to pass through the annular member loosely, the annular member does not unexpectedly move in the front-rear direction, and the effect of suppressing rattling in the shaft cylinder of the writing body can be maintained. In addition, when replacing the writing body, the user does not need to remove the annular member, and the loss of the annular member can be prevented.

[0010] Preferably, the writing instrument is a retractable writing instrument that accommodates the writing body movably in the front-rear direction in the shaft cylinder, accommodates an elastic body that biases the writing body rearward in the front shaft, and has a retracting mechanism that projects the pen tip from the opening by moving the writing body forward against the rearward biasing force of the elastic body.

[0011] In the present invention, the structure of the writing instrument is not limited, such as a capped writing instrument equipped with a cap that covers the pen tip, or a retractable writing instrument in which the writing body moves back and forth within the shaft tube and protrudes from and retracts into the front end opening of the shaft tube. However, especially in the case of a retractable writing instrument, the above-described effects of the present invention can be more enjoyed.

[0012] Preferably, the ink storage tube is made of a metal pipe. As a result, the wall thickness of the ink storage tube can be reduced, and more ink can be stored.

Effects of the Invention

[0013] According to the present invention, the annular member does not unexpectedly move in the front-rear direction, and the effect of suppressing rattling of the writing body within the shaft tube can be maintained. Further, when replacing the writing body, the user does not need to remove the annular member, and loss of the annular member can be prevented.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0015] Hereinafter, two embodiments of the present invention will be described with reference to the drawings. In the writing instrument 10 of the present embodiment, "front" or "lower" refers to the side of the pen tip 121 in the writing instrument 10, and "rear" or "upper" refers to the opposite side thereof.

[0016] <First Embodiment> The first embodiment of the present invention is shown in FIGS. 1 to 4. FIG. 1 is a schematic longitudinal sectional view of the writing instrument 10 in the first embodiment of the present invention, showing a state where the pen tip 121 does not protrude (pen tip retracted state). In the present embodiment, the writing instrument 10 is a retractable writing instrument in which the writing body moves back and forth in the shaft cylinder 11, and the pen tip 121 protrudes and retracts from the front end opening of the shaft cylinder 11. However, the present invention is also applicable to a capped writing instrument provided with a cap for covering the pen tip.

[0017] FIG. 2 is an enlarged longitudinal sectional view of the portion where the annular member 13 of FIG. 1 is mounted. FIG. 3 is a perspective view showing a state where the annular member 13 is fitted to the rear end of the front shaft 111. In other words, FIG. 3 shows the state of the front shaft 111 separated from the rear shaft 114 for replacing the writing body. FIG. 4(a) is a front view of the annular member 13 of the writing instrument 10 of FIG. 1. FIG. 4(b) is a bottom view of the annular member 13 of FIG. 4(a). FIG. 4(c) is a perspective view of the annular member 13 of FIG. 4(a).

[0018] As shown in FIG. 1, the writing instrument 10 of the present embodiment includes a shaft cylinder 11 having an opening at the front end, a writing body housed in the shaft cylinder 11, an annular member 13 mounted on the inner surface of the shaft cylinder 11, an operation portion 16 provided on the side surface of the shaft cylinder 11 for operating the protrusion and retraction of the pen tip 121, and an elastic body 14 for biasing the writing body rearward.

[0019] Further, the writing body includes a pen tip 121, an ink storage tube 122 that stores ink inside, and a holder 123 that connects the pen tip 121 and the ink storage tube 122. Further, the shaft cylinder 11 is composed of a front shaft 111 having an opening through which the pen tip 121 protrudes, and a rear shaft 114 that is detachably screwed to the front shaft 111. Further, the writing instrument 10 of the present embodiment includes a crown attached to the rear portion of the rear shaft 114, and a soft member 15 inserted into the crown. The annular member 13 is attached to the rear portion of the front shaft 111, and the writing body is provided so as to pass through the annular member 13.

[0020] · Retractable writing instrument As shown in FIG. 1, the writing instrument 10 of the present embodiment is a retractable writing instrument provided with a retraction mechanism that houses a writing body movably back and forth in a shaft cylinder 11, houses an elastic body 14 that biases the writing body rearward in the front shaft 111, and protrudes the pen tip 121 from the opening to a protruding state by moving the writing body forward against the rearward biasing of the elastic body 14.

[0021] The retraction mechanism of the retractable writing instrument of the present embodiment is a side slide type retraction mechanism using a rotary cam mechanism. It includes a cam portion formed on the inner surface of the rear shaft 114, a rotating member that engages with the cam portion and abuts against the rear end of the writing body, an operation portion 16 that engages with the rotating member and protrudes radially outward from a slide hole on the side surface of the rear shaft 114, and an elastic body 14 (for example, a compression coil spring) that is housed in the shaft cylinder 11 and biases the writing body 12 rearward. The retraction mechanism of the present embodiment is a double knock type in which both the pen tip protruding operation and the pen tip retracting operation slide the operation portion 16 forward.

[0022] · Shaft cylinder As shown in FIGS. 1 to 3, the shaft cylinder 11 is composed of a front shaft 111 having an opening through which the pen tip 121 protrudes at the front end, and a rear shaft 114 that is detachably screwed to the front shaft 111. In the present embodiment, the front shaft 111 and the rear shaft 114 are cylindrical bodies manufactured by injection molding or extrusion molding of synthetic resin with both ends open.

[0023] The front shaft 111 includes an opening at the front end where the pen tip 121 protrudes, and a male threaded portion 112 at the rear portion that engages with the female threaded portion 115 of the rear shaft 114. Also, at the rear end of the front shaft 111, there is a fitting portion 113 for mounting (fitting) an annular member 13 described later. The fitting portion 113 is provided on the inner surface of the rear end of the front shaft 111 and is press-fitted and locked (fitted) with the front shaft fitting portion 131 of the annular member 13. In the present embodiment, the fitting portion 113 is provided with a circumferential smooth fitting surface, but a circumferential inward protrusion or concave groove may be provided.

[0024] Note that the fitting portion 113 of the front shaft 111 may be provided on the outer surface of the rear end of the front shaft 111. In that case, the front shaft fitting portion 131 of the annular member 13 is provided on the inner surface of the annular member 13. Even when the fitting portion 113 of the front shaft 111 is provided on the outer surface of the rear end of the front shaft 111, the fitting portion 113 may be provided with a circumferential smooth fitting surface, or a circumferential outward protrusion or concave groove may be provided.

[0025] · Annular member The annular member 13 of the present embodiment includes a front shaft fitting portion 131 that fits with the inner surface of the rear end of the front shaft 111, and a guide portion 134 in front of the front shaft fitting portion 131. Also, the annular member 13 includes a through hole 133 that penetrates in the front-rear direction, and a flange portion 135 that abuts against the rear end of the front shaft 111. A chamfered region 132 is provided at the rear end of the through hole 133.

[0026] Also, in the writing instrument 10 of the present embodiment, the writing body 12 is provided so as to freely penetrate through the through hole 133. That is, the outer diameter of the writing body 12 is smaller than the inner diameter of the through hole 133. In the present embodiment, the outer diameter of the writing body 12 (ink storage tube 122) is φ6.1 mm, and the inner diameter of the through hole 133 of the annular member 13 is φ6.3.

[0027] The front shaft fitting portion 131 of the annular member 13 of this embodiment is provided with a circumferential smooth fitting surface, but a circumferential outward protrusion or an inner hole protrusion may also be provided. When the fitting portion 113 of the front shaft 111 is provided on the outer surface of the rear end of the front shaft 111, the front shaft fitting portion 131 of the annular member 13 is provided on the inner surface of the annular member 13. In this case, the front shaft fitting portion 131 of the annular member 13 may be provided with a circumferential smooth fitting surface, or a circumferential inner hole protrusion or a concave groove may be provided. Further, the front shaft 111 and the annular member 13 may be integrally formed by adhesion or two-color molding.

[0028] Further, in the annular member 13 of this embodiment, as shown in FIG. 2, a chamfered region 132 is provided on the entire circumference of the rear end of the through hole 133. The chamfered region 132 preferably has a radial width in the range of 0.1 mm to 2.0 mm and an inclination angle θ in the range of 10° to 60° in a cross section including the central axis of the through hole 133. In this embodiment, the radial width is 0.6 mm and the inclination angle θ is 30°.

[0029] The annular member 13 of this embodiment is made of polypropylene. However, the material of the annular member 13 used in the present invention is not limited to resin (for example, polypropylene, polyacetal, polycarbonate, polyethylene), and may be made of metal (for example, brass, stainless steel).

[0030] ·Writing body The writing body 12 of this embodiment includes a pen tip 121, an ink storage tube 122 that stores ink therein, a holder 123 that connects the pen tip 121 and the ink storage tube 122, thermochromic ink filled in the ink storage tube 122, and a follower (for example, a high-viscosity fluid) filled at the rear end of the thermochromic ink and advancing as the thermochromic ink is consumed.

[0031] The pen tip 121 is made of, for example, a metal ball pen tip that rotatably holds a ball at the front end. Further, a tail plug having a vent hole through which the ink storage tube 122 and the outside communicate is attached to the rear end opening of the ink storage tube 122. Inside the pen tip 121, a spring that presses the front ball forward is accommodated. The spring has a configuration in which a rod portion is provided at the front end of a compression coil spring, and the front end of the rod portion is in contact with the rear surface of the ball. When not writing, the ball is closely attached to the inner surface of the inward front edge portion at the front end of the ball pen tip due to the forward biasing of the spring, and leakage of ink from the front end of the pen tip 121 and evaporation of the ink can be prevented.

[0032] The ink storage tube 122 of the present embodiment is made of a metal pipe using stainless steel (specifically, SUS304). Further, the material of the ink storage tube 122 used in the present invention is not limited to metal, and may be resin (for example, made of polypropylene or polyethylene).

[0033] ·Soft member As shown in FIG. 1, when the writing instrument 10 is a thermochromic writing instrument having thermochromic ink inside, a soft member 15 may be further provided. The soft member 15 can rub the writing of the thermochromic ink and thermochromically change the writing of the thermochromic ink with the frictional heat generated at that time.

[0034] The elastic synthetic resin constituting the soft member 15 is preferably made of a low-wear elastic material that hardly generates wear dust (eraser dust) during friction, rather than a high-wear elastic material (for example, eraser).

[0035] The elastic material constituting the soft member 15 is preferably, for example, an elastic synthetic resin (rubber, elastomer), and examples thereof include silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butylene-styrene copolymer), fluorine-based resin, chloroprene resin, nitrile resin, polyester-based resin, ethylene propylene diene rubber (EPDM), or a mixture of two or more rubber elastic materials, and a mixture of a rubber elastic material and a synthetic resin.

[0036] · Ink In the present embodiment, the ink accommodated in the writing body 12 (ink storage tube 122) is thermochromic ink. The thermochromic ink is preferably reversible thermochromic ink. The reversible thermochromic ink can be configured by singly or in combination using various types such as a heat-decoloring type that decolors by heating from a coloring state, a color memory retention type that mutually changes and retains a coloring state or a decoloring state in a specific temperature range, or a heat-coloring type that colors by heating from a decoloring state and returns to the decoloring state by cooling from the coloring state.

[0037] As the coloring material contained in the reversible thermochromic ink, for example, a reversible thermochromic pigment in which a reversible thermochromic composition containing at least the essential three components of (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) a reaction medium that determines the occurrence temperature of a reaction (color-forming reaction) in which the two are chemically bonded is encapsulated in microcapsules is preferably used.

[0038] Note that the ink used in the present invention is not limited to thermochromic ink, and other ink compositions other than thermochromic ink can also be used. For example, it may be appropriately selected according to the use as a liquid ejecting tool such as writing ink, correction fluid, or liquid paste or cosmetic liquid. In the case of writing ink, it is not particularly limited such as oil-based ink or water-based ink.

[0039] <Second Embodiment> The second embodiment of the present invention is shown in FIGS. 5 and 6. FIG. 5 is an enlarged longitudinal sectional view of a main part of a writing instrument in the second embodiment of the present invention, and shows an annular member 23 fitted on the inner surface of the rear shaft 114. FIG. 6(a) is a front view of the annular member 23 of the second embodiment. FIG. 6(b) is a bottom view of the annular member 23 of FIG. 6(a). FIG. 6(c) is a perspective view of the annular member 23 of FIG. 6(a).

[0040] The writing instrument of the present embodiment is a modification of the first embodiment. The differences from the first embodiment are that the annular member 23 is fitted to the rear shaft 114 and the shape of the annular member 23 is different. Since the other configurations of the second embodiment are substantially the same as those of the first embodiment, detailed descriptions thereof are omitted.

[0041] · Annular member The annular member 23 of the present embodiment includes a rear shaft fitting portion 231 that fits into the inner surface of the rear shaft 114 and a guide portion 234 on the outer side in the axial direction of the rear shaft fitting portion 231. The rear shaft fitting portion 231 and the guide portion 234 are provided on at least one outer surface of the annular member 23. Further, the annular member 23 includes a through hole 233 that penetrates in the front-rear direction, and a chamfered region 232 is provided at at least one end of the through hole 233. That is, when the rear shaft fitting portion 231 and the chamfered region 232 are provided at both ends of the annular member 23, a front-rear symmetric shape can be achieved. Thereby, the directionality of the parts is eliminated and the assemblability is improved.

[0042] The rear shaft fitting portion 231 of the present embodiment is provided with a concave groove formed in a circumferential shape, but it may also be an outward protrusion or a circumferentially smooth surface provided in a circumferential shape. Note that the fitting portion 116 of the rear shaft 114 in the present embodiment is an inward protrusion formed in a circumferential shape. The inner hole protrusion also functions to prevent the rotating member of the projecting and retracting mechanism from falling out of the rear shaft 114.

[0043] The writing instrument 10 configured as described above operates as follows.

[0044] According to the present embodiment, the annular member 13 is press-fitted and locked (fitted, engaged) to the rear portion of the front shaft 111, and the writing body 12 is provided so as to penetrate the annular member 13. Thereby, since the annular member 13 is securely fixed to the rear portion of the front shaft 111, it does not move unexpectedly in the front-rear direction. Further, thereby, the effect of suppressing the play of the writing body 12 within the shaft cylinder 11 can be maintained. Further, when replacing the writing body 12, the user does not need to remove the annular member 13, and loss of the annular member 13 can be prevented.

[0045] Also, the writing instrument 10 of the present embodiment is a retractable writing instrument. According to the present embodiment, since the writing body 12 is provided so as to penetrate through the annular member 13, even if the writing body 12 of the retractable writing instrument moves back and forth within the shaft cylinder 11, the annular member 13 is press-fitted and locked (fitted, engaged) to the rear portion of the front shaft 111 and thus does not move in the front-rear direction. That is, applying the present invention to a retractable writing instrument can more remarkably enjoy the above-described effects of the present invention. However, the same actions and effects can be achieved even with a capped writing instrument provided with a cap that covers the pen tip.

[0046] Also, generally, an ink storage tube made of a metal pipe can have a thinner wall thickness. As a result, the ink storage tube 122 made of a metal pipe can store more ink than an ink storage tube made of a resin pipe (when the outer diameters of the ink storage tubes are substantially the same).

[0047] On the other hand, increasing the amount of ink stored by using the ink storage tube 122 made of a metal pipe will relatively increase the weight of the writing body 12 compared to a writing body provided with an ink storage tube made of a resin pipe having the same outer diameter.

[0048] As a result, the writing body 12 provided with the ink storage tube 122 made of a metal pipe is more likely to vibrate greatly due to external vibration, and there is a possibility of significant rattling within the shaft cylinder 11.

[0049] Therefore, applying the present invention to a writing instrument provided with a writing body 12 in which the ink storage tube 122 is a metal pipe can more remarkably enjoy the above-described effects of the present invention even when using a heavy writing body 12. However, the same actions and effects can be achieved even when the ink storage tube is a resin pipe.

[0050] Also, in one aspect of the present embodiment, the annular member 13 includes a front shaft fitting portion 131 that fits into the inner surface of the rear end of the front shaft 111. Thereby, since it is not necessary to reduce the inner diameter of the front shaft 111, it becomes easier to provide a taper on the inner surface of the front shaft 111, and the formation of the front shaft 111 becomes easier.

[0051] Further, the annular member 13 includes a through hole 133 that penetrates in the front-rear direction and a flange portion 135 that abuts against the rear end of the front shaft 111. Thereby, the annular member 13 can be easily and surely attached to the front shaft 111. As a result, play within the shaft tube 11 of the writing body 12 can be surely suppressed.

[0052] Also, a chamfered region 132 is provided at the rear end of the through hole 133. Thereby, when replacing the writing body 12, damage to the pen tip 121 due to the pen tip 121 hitting the end face (flange portion 135) of the annular member 13 can be prevented. Also, it becomes easier to insert the writing body 12 into the front shaft 111 (annular member 13). Further, the annular member 13 includes a guide portion 134 in front of the front shaft fitting portion 131, which makes it easier to insert the annular member 13 onto the front shaft 111 and improves the assemblability.

[0053] Also, in one aspect of the present embodiment, the annular member 23 includes a rear shaft fitting portion 231 that fits into the inner surface of the rear shaft 114. That is, the annular member 23 is housed in the inner surface of the rear shaft 114. Thereby, when replacing the writing body 12, since the user does not come into contact with the annular member 23, it is possible to prevent the annular member 23 from coming off and getting lost.

[0054] In addition, the annular member 23 is provided with a through hole 233 penetrating in the front-rear direction, and a chamfered region 232 is provided at at least one end of the through hole 233. That is, when the rear shaft fitting portion 231 and the chamfered region 232 are provided at both ends of the annular member 23, it can have a front-rear symmetric shape. As a result, the directionality of the parts is eliminated, and the assemblability is improved. Further, when replacing the writing body 12, it becomes easy to insert the writing body 12 into the rear shaft 114 (annular member 23). Further, the annular member 23 is provided with a guide portion 234 outward in the axial direction of the rear shaft fitting portion 231, so that it becomes easy to insert the annular member 23 into the rear shaft 114, and the assemblability is improved.

Explanation of Signs

[0055] 10 Writing instrument 11 Shaft cylinder 111 Front shaft 112 Male thread portion 113 Fitting portion 114 Rear shaft 115 Female thread portion 116 Fitting portion 12 Writing body 121 Pen tip 122 Ink storage tube 123 Holder 13 Annular member 131 Front shaft fitting portion 132 Chamfered region 133 Through hole 134 Guide portion 135 Flange portion 14 Elastic body 15 Soft member 16 Operating portion 23 Annular member 231 Rear shaft fitting portion 232 Chamfered region 233 Through hole 234 Guide portion

Claims

1. A shaft cylinder having an opening at the front end, a writing body accommodated in the shaft cylinder, and an annular member attached to the inner surface of the shaft cylinder, wherein the writing body includes a pen tip and an ink storage tube that stores ink therein, the shaft cylinder consists of at least a front shaft having the opening through which the pen tip protrudes and a rear shaft that is detachably screwed to the front shaft, the annular member is fitted to the inner surface of the rear end of the front shaft, and the writing body is a writing instrument provided to penetrate the annular member loosely.

2. The writing instrument according to claim 1, wherein the annular member includes a front shaft fitting portion that fits with the inner surface of the rear end of the front shaft, a through hole that penetrates in the front-rear direction, and a flange portion that abuts against the rear end of the front shaft, and a chamfered region is provided at the rear end of the through hole.

3. A shaft cylinder having an opening at the front end, a writing body accommodated in the shaft cylinder, and an annular member attached to the inner surface of the shaft cylinder, wherein the writing body includes a pen tip and an ink storage tube that stores ink therein, the shaft cylinder consists of at least a front shaft having the opening through which the pen tip protrudes and a rear shaft that is detachably screwed to the front shaft, the annular member is fitted to the inner surface of the rear shaft, the annular member includes a rear shaft fitting portion that fits with the inner surface of the rear shaft and a through hole that penetrates in the front-rear direction, a chamfered region is provided at at least one end of the through hole, and the writing body is a writing instrument provided to penetrate the annular member loosely.

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