ballpoint pen

Abstract

To provide a ballpoint pen capable of avoiding dropout of the annular elastic body when the ballpoint pen tip is withdrawn or protruded from the front end hole and to maintain the anti-rattling performance of the ballpoint pen tip.SOLUTION: When the front end of a ballpoint pen tip 4 is projected outward from a front end hole 21 of a barrel 2, an annular elastic body 7 is interposed between the outer surface of the ballpoint pen tip 4 and the inner surface of the front end hole 21 of the barrel 2. The ballpoint pen tip 4 includes: a front cylindrical portion 41 protruding forward from the front end of the tip holding cylinder 5; a rear cylindrical portion 42 formed behind the front cylindrical portion 41; and a mounting portion 43 formed on the outer surface between the front cylindrical portion 41 and the rear cylindrical portion 42 and to which the annular elastic body 7 is attached. The outer diameter of the mounting portion 43 is set to be smaller than the outer diameter of the rear end of the front cylindrical portion 41 and larger than the outer diameter of the rear cylindrical portion 42. A rearward-facing step 44 is formed between the front cylindrical portion 41 and the mounting portion 43. The annular elastic body 7 is sandwiched between the backward-facing step 44 and the front end of the tip holding cylinder 55 in a back and forth compressed state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a ballpoint pen, and more particularly to a ballpoint pen in which an annular elastic body is interposed between the outer surface of the ballpoint pen tip and the inner surface of the front end hole of the barrel when the front end of the ballpoint pen tip protrudes outward from the front end hole of the barrel. [Background technology]

[0002] Conventionally, Patent Document 1 discloses a structure for preventing the writing tip from wobbling when writing, in which a groove is provided at an appropriate position on the writing tip and an O-ring with an outer diameter approximately equal to the inner diameter of the tip of the barrel is fitted into the groove. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 5-85683 Summary of the Invention [Problem to be solved by the invention]

[0004] The structure of Patent Document 1 has the risk that when the writing tip (corresponding to the ballpoint pen tip in the present application) protrudes or retracts from the front end hole of the barrel, the O-ring (corresponding to the annular elastic body in the present application) may fall off from the groove due to sliding against the inner surface of the front end hole of the barrel (corresponding to the front end hole in the present application).

[0005] The present invention aims to solve the above-mentioned problems of the prior art by providing a ballpoint pen that can prevent the annular elastic body from falling off when the ballpoint pen tip is inserted or retracted through the front end hole, thereby maintaining the ballpoint pen tip's anti-wobble performance. In the present invention, "front" refers to the ball side of the ballpoint pen tip, and "rear" refers to the opposite side. [Means for solving the problem]

[0006] The first invention of the present application is a ballpoint pen comprising a barrel and a writing body accommodated in the barrel, the writing body comprising a ballpoint pen tip and a tip holding tube to which the rear end of the ballpoint pen tip is attached, the front end of the ballpoint pen tip is configured to be able to protrude outward from a front end hole of the barrel, and in a state in which the front end of the ballpoint pen tip protrudes outward from the front end hole of the barrel, a ring-shaped elastic body is interposed between the outer surface of the ballpoint pen tip and the inner surface of the front end hole of the barrel, and the ballpoint pen tip has a front end that rotatably holds a ball and The tip holding tube has a front tubular portion that protrudes forward from the front end of the tip holding tube, a rear tubular portion that is formed rearward of the front tubular portion and is attached to a mounting hole at the front end of the tip holding tube, and an attachment portion that is formed on the outer surface between the front tubular portion and the rear tubular portion and to which the annular elastic body is attached, wherein the outer diameter of the attachment portion is set to be smaller than the outer diameter of the rear end of the front tubular portion and greater than the outer diameter of the rear tubular portion, a rearward step portion is formed between the front tubular portion and the attachment portion, and the annular elastic body is clamped between the rearward step portion and the front end of the tip holding tube in a front-to-back compressed state.

[0007] In the ballpoint pen of the first invention, the annular elastic body is firmly fixed to the writing body by being clamped in a front-to-back compressed state between the rearward-facing step portion and the front end of the tip holding tube, so that the annular elastic body can be prevented from falling off when the ballpoint pen tip is inserted into or protruded from the front end hole, and the ballpoint pen tip's rattle prevention performance can be maintained.

[0008] The second invention of the present application is a ballpoint pen according to the first invention, wherein the ballpoint pen tip has a regulating wall portion, the tip holding tube has an abutting wall portion, and when the rear tube portion of the ballpoint pen tip is attached to the mounting hole of the tip holding tube, the regulating wall portion and the abutting wall portion abut in the front and rear directions.

[0009] The ballpoint pen of the second invention can maintain a constant amount of compression in the front and back of the annular elastic body, and can reduce variation in the amount of radial expansion deformation of the outer surface of the annular elastic body (i.e., the outer diameter of the annular elastic body after installation).

[0010] The third invention of the present application is characterized in that, in the ballpoint pen of the second invention, a stepped regulating wall portion is formed between the attachment portion of the ballpoint pen tip and the rear tube portion, and the abutment wall portion is formed on the front end of the tip holding tube or on the inner surface of the tip holding tube.

[0011] According to the ballpoint pen of the third invention, the restricting wall portion and the abutting wall portion can be reliably abutted against each other.

[0012] The fourth invention of the present application requires that, in the ballpoint pen of the second invention, the regulating wall portion is formed at the rear end of the rear tube portion of the ballpoint pen tip or on the outer surface of the rear tube portion, and the abutment wall portion is formed on the inner surface of the tip holding tube.

[0013] According to the ballpoint pen of the fourth invention, the restricting wall portion and the abutting wall portion can be reliably abutted against each other. [Effects of the Invention]

[0014] In the ballpoint pen of the present invention, the annular elastic body is firmly fixed to the writing body, so that the annular elastic body is prevented from falling off when the ballpoint pen tip is inserted or projected from the front end hole, and the ballpoint pen tip's rattle prevention performance can be maintained. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a longitudinal cross-sectional view of a main part of a first embodiment of a ballpoint pen according to the present invention, showing a ballpoint pen tip protruding state. [Figure 2] 2 is a longitudinal cross-sectional view of a main part showing the ballpoint pen tip of FIG. 1 in a sunk state. [Figure 3] FIG. 2 is a longitudinal cross-sectional view of a main part of the writing tool of FIG. [Figure 4] FIG. 4 is a vertical cross-sectional view of the ballpoint pen tip of FIG. 3. [Figure 5] FIG. 4 is a longitudinal sectional view of a main part of the tip holding cylinder of FIG. 3. [Figure 6] FIG. 10 is a longitudinal cross-sectional view of the main part of the writing body of a second embodiment of the ballpoint pen of the present invention. [Figure 7] FIG. 7 is a vertical cross-sectional view of the ballpoint pen tip of FIG. 6. [Figure 8] FIG. 7 is a longitudinal sectional view of a main part of the tip holding cylinder of FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0016] First Embodiment A ballpoint pen 1 according to a first embodiment of the present invention is shown in FIGS.

[0017] ·Shaft cylinder The barrel 2 is a cylindrical body made of synthetic resin or metal material. The writing element 3 is housed inside the barrel 2 so that it can move back and forth. The front end of the barrel 2 is formed with a tapered outer surface, and a front end hole 21 is formed at the front end, penetrating in the axial direction. The ballpoint pen tip 4 of the writing element 3 is configured to be able to appear and disappear through the front end hole 21 of the barrel 2.

[0018] A spring 8 (compression coil spring) is housed within the front end of the barrel 2. The front end of the spring 8 is engaged with the inner wall of the front end of the barrel 2. The writing element 3 is urged rearward by the spring 8. A retraction mechanism (not shown) is provided within the barrel 2 to move the writing element 3 forward against the rearward urging of the writing element 3. Examples of the retraction mechanism include a rear-end knock type in which the ballpoint pen tip 4 is protruded and retracted from the front-end hole 21 by pressing forward an operating part provided at the rear end of the barrel 2; a side slide type in which the ballpoint pen tip 4 is protruded and retracted from the front-end hole 21 by sliding forward an operating part provided on the side of the barrel 2; and a rotation type in which the ballpoint pen tip 4 is protruded and retracted from the front-end hole 21 by rotating an operating part provided on the outer surface of the barrel 2.

[0019] ·Cursive The writing element 3 comprises a ballpoint pen tip 4, a tip holding cylinder to which the ballpoint pen tip 4 is attached, and an ink reservoir cylinder 6 to which the tip holding cylinder 5 is attached.

[0020] Ballpoint pen tip The ballpoint pen tip 4 comprises a main body made of a metal (for example, stainless steel) cylinder and a ball 4a rotatably held at the front end of the main body. As shown in Figures 3 and 4, the main body comprises a front cylinder portion 41 at the front end of which the ball 4a is held, an attachment portion 43 connected to the rear of the front cylinder portion 41 and to which the annular elastic body 7 is attached, and a rear cylinder portion 42 connected to the rear of the attachment portion 43.

[0021] The front tubular portion 41 has a conical outer surface and a cylindrical outer surface connected to the rear of the front tubular portion 41. The mounting portion 43 has a cylindrical outer surface. The mounting portion 43 has an outer diameter smaller than the outer diameter of the rear end of the front tubular portion 41. The rear tubular portion 42 has a substantially cylindrical outer surface. The rear tubular portion 42 has an outer diameter smaller than the outer diameter of the mounting portion 43. The rear tubular portion 42 is press-fitted into the mounting hole 54.

[0022] A rearward step 44 is formed between the front tubular portion 41 and the mounting portion 43 (i.e., between the rear end of the front tubular portion 41 and the front end of the mounting portion 43). The rearward step 44 is made of a surface perpendicular to the axis. The rearward step 44 is formed in an annular shape.

[0023] A stepped restricting wall portion 45 is formed between the mounting portion 43 and the rear tubular portion 42 (i.e., between the rear end of the mounting portion 43 and the front end of the rear tubular portion 42). The restricting wall portion 45 has a surface perpendicular to the axis.

[0024] The ballpoint pen tip 4 may contain a spring in its body to bias the ball 4a forward.

[0025] Chip holder tube 1 and 2, the tip retaining cylinder 5 includes a front cylinder portion 51, an annular flange portion 53 integrally connected to the rear of the front cylinder portion 51, and a rear cylinder portion 52 integrally connected to the rear of the flange portion 53. The tip retaining cylinder 5 is obtained by molding a synthetic resin (for example, polypropylene).

[0026] The front tube portion 51 is made of a tapered cylindrical body. An attachment hole 54 that opens forward is formed at the front end of the front tube portion 51. The rear tube portion 42 of the ballpoint pen tip 4 is press-fitted and fixed into the attachment hole 54. A forward-facing step is formed on the outer surface of the front tube portion 51, and the rear end of the spring 8 is engaged with the forward-facing step. The flange portion 53 abuts against the front end of the ink reservoir tube 6. The rear tube portion 52 is press-fitted and fixed into the front-end opening of the ink reservoir tube 6.

[0027] Ink storage tube The ink reservoir 6 is a cylindrical body obtained by extrusion molding of a synthetic resin (for example, polypropylene). Ink is stored inside the ink reservoir 6. The ink inside the ink reservoir 6 is supplied into the ballpoint pen tip 4 through the tip holding tube 5 and is ejected to the outside as the ball 4a at the front end of the ballpoint pen tip 4 rotates. Alternatively, the tip holding tube 5 and the ink reservoir 6 may be formed integrally, so that the ink reservoir 6 also serves as the tip holding tube 5.

[0028] ·Annular elastic body The annular elastic body 7 is formed from a material having rubber elasticity. Examples of materials having rubber elasticity include synthetic resins (rubber, elastomers) having rubber elasticity, such as silicone rubber, nitrile rubber, ethylene-propylene-diene rubber, butyl rubber, chloroprene rubber, acrylonitrile butadiene rubber, urethane rubber, fluororubber, polysulfide rubber, olefin-based thermoplastic elastomers, and styrene-based thermoplastic elastomers. The annular elastic body 7 is made of a continuous linear portion in an annular shape. Before the annular elastic body 7 is attached, the longitudinal cross section of the linear portion is circular.

[0029] With the rear tube portion 42 of the ballpoint pen tip 4 press-fitted and fixed into the mounting hole 54 of the tip holding tube 5, the annular elastic body 7 is sandwiched between the rearward step portion 44 of the ballpoint pen tip 4 and the front end of the tip holding tube 5 and is compressed back and forth. In this state, the front surface of the annular elastic body 7 is in annular, tight contact with the rearward step portion 44, the rear surface of the annular elastic body 7 is in annular, tight contact with the front end of the tip holding tube 5, and the inner surface of the annular elastic body 7 is in annular, tight contact with the outer surface of the attachment portion 43. This prevents ink from leaking from inside the writing body between the ballpoint pen tip 4 and the tip holding tube 5.

[0030] With the rear cylindrical portion 42 of the ballpoint pen tip 4 press-fitted and fixed in the mounting hole 54 of the tip holding tube 5, the annular elastic body 7 protrudes radially outward from the rear end of the rear cylindrical portion 42 of the ballpoint pen tip 4, and also protrudes radially outward from the front end of the tip holding tube 5. With the front end of the ballpoint pen tip 4 protruding outward from the front end hole 21 of the barrel 2, the outer surface of the annular elastic body 7 and the inner surface of the front end hole 21 of the barrel 2 are pressed together, preventing the ballpoint pen tip 4 from rattling.

[0031] Attachment of annular elastic body 7 The attachment of the annular elastic body will be described in order. First, the annular elastic body 7 is attached to the attachment portion 43 of the ballpoint pen tip 4, and then the rear tube portion 42 of the ballpoint pen tip 4 is press-fitted into the attachment hole 54 of the tip holding tube 5. Then, the restricting wall portion 45 of the ballpoint pen tip 4 abuts against the front end (abutment wall portion 55) of the tip holding tube 5, completing the press-fitting of the ballpoint pen tip into the attachment hole 54 of the tip holding tube 5. As a result, the ballpoint pen tip 4 is fixed to the tip holding tube 5, and the annular elastic body 7 is sandwiched between the rearward-facing step portion 44 of the ballpoint pen tip 4 and the front end of the tip holding tube 5 in a state compressed in the front-rear direction.

[0032] As shown in FIGS. 3 and 4, in a state where the rear tube portion 42 of the ballpoint pen tip 4 is press-fitted and fixed in the mounting hole 54 of the tip holding tube 5, the radial height between the mounting portion 43 and the rear end of the front tube portion 41 is H1, the radial height between the mounting portion 43 and the front end of the tip holding tube 5 is H2, the radial protrusion amount of the annular elastic body 7 from the rear end of the front tube portion 41 is P1, and the radial protrusion amount of the annular elastic body 7 from the front end of the tip holding tube 5 is P2. P1 is smaller than H1 (P1

[0033] Furthermore, when the rear tube portion 42 of the ballpoint pen tip 4 is press-fitted and fixed into the mounting hole 54 of the tip holding tube 5, the annular elastic body 7 is compressed in the front-to-rear direction and bulges outward in the radial direction, and the radial thickness T1 of the linear portion is set larger than the axial thickness T2 of the linear portion (T1>T2). This allows the annular elastic body 7 to be strongly compressed between the rearward step portion 44 and the front end of the tip holding tube 5, enabling the annular elastic body 7 to be firmly attached.

[0034] ​The ballpoint pen 1 of this embodiment comprises a barrel 2 and a writing body 3 housed in the barrel 2. The writing body 3 comprises a ballpoint pen tip 4 and a tip holding tube 5 to which the rear end of the ballpoint pen tip 4 is attached. The front end of the ballpoint pen tip 4 is configured to be able to protrude outward from a front end hole 21 of the barrel 2. When the front end of the ballpoint pen tip 4 protrudes outward from the front end hole 21 of the barrel 2, an annular elastic body 7 is interposed between the outer surface of the ballpoint pen tip 4 and the inner surface of the front end hole 21 of the barrel 2. The ballpoint pen tip 4 rotatably holds a ball 4a at its front end. The tip holding tube 5 includes a front tubular portion 41 that protrudes forward from the front end thereof, a rear tubular portion 42 that is formed rearward of the front tubular portion 41 and that is attached to a mounting hole 54 at the front end thereof, and a mounting portion 43 that is formed on the outer surface between the front tubular portion 41 and the rear tubular portion 42 and to which the annular elastic body 7 is attached, and the outer diameter of the mounting portion 43 is set to be smaller than the outer diameter of the rear end of the front tubular portion 41 and greater than the outer diameter of the rear tubular portion 42, and a rearward step portion 44 is formed between the front tubular portion 41 and the mounting portion 43, and the annular elastic body 7 is clamped between the rearward step portion 44 and the front end of the tip holding tube 5 in a front-to-back compressed state.

[0035] As a result, in the ballpoint pen 1 of this embodiment, the annular elastic body 7 is firmly fixed to the writing body 3 by being clamped in a front-to-back compressed state between the rearward-facing step portion 44 and the front end of the tip holding tube 5, thereby preventing the annular elastic body 7 from falling off when the ballpoint pen tip 4 is inserted or protruded from the front end hole 21, and maintaining the anti-rattle performance of the ballpoint pen tip 4.

[0036] In the ballpoint pen 1 of this embodiment, the ballpoint pen tip 4 is provided with a restricting wall portion 45, the tip holding tube 5 is provided with an abutting wall portion 55, and when the rear tube portion 42 of the ballpoint pen tip 4 is attached to the attachment hole 54 of the tip holding tube 5, the restricting wall portion 45 and the abutting wall portion 55 abut against each other from the front to the back. As a result, the ballpoint pen 1 of this embodiment can maintain a constant amount of compression in the front and rear of the annular elastic body 7, and can suppress variation in the amount of radial expansion deformation of the outer surface of the annular elastic body 7 (i.e., the outer diameter of the annular elastic body 7 after attachment).

[0037] In the ballpoint pen 1 of this embodiment, the stepped regulating wall portion 45 is formed between the mounting portion 43 of the ballpoint pen tip 4 and the rear tube portion 42, and the abutting wall portion 55 is formed at the front end of the tip holding tube 5. As a result, in the ballpoint pen 1 of this embodiment, the regulating wall portion 45 and the abutting wall portion 55 can be reliably abutted against each other. In addition, in the ballpoint pen of this embodiment, an abutting wall portion may be formed on the inner surface of the tip holding tube 5.

[0038] <Second embodiment> A ballpoint pen 1 according to a second embodiment of the present invention is shown in FIGS. The second embodiment differs from the first embodiment in the configuration of the restricting wall portion 45 and the abutting wall portion 55. The other configurations are the same as those of the first embodiment.

[0039] 6 and 7, the outer diameter of the attachment portion 43 is set to be the same as the outer diameter of the front portion of the rear tube portion 42, and there is no difference in outer diameter between the attachment portion 43 and the rear tube portion 42. A restricting wall portion 45 is formed at the rear end of the rear tube portion 42 of the ballpoint pen tip 4, and an abutting wall portion 55 is formed on the inner surface of the tip holding tube 5 (the bottom wall of the mounting hole 54). When the rear tube portion 42 of the ballpoint pen tip 4 is press-fitted and fixed in the mounting hole 54 of the tip holding tube 5, the restricting wall portion 45 at the rear end of the rear tube portion 42 of the ballpoint pen tip 4 and the abutting wall portion 55 on the inner surface of the tip holding tube 5 abut against each other from the front to the rear. This ensures reliable abutment between the restricting wall portion 45 and the abutting wall portion 55.

[0040] In addition, in the ballpoint pen of this embodiment, the restricting wall portion may be formed on the outer surface of the rear cylindrical portion 42 of the ballpoint pen tip.

[0041] In addition to the configuration of the retractable ballpoint pen described above, the present invention may also be configured such that the writing body is housed and fixed within the barrel and the front end of the ballpoint pen tip always protrudes outside from the front end hole of the barrel (a cap-type ballpoint pen). [Explanation of symbols]

[0042] 1 ballpoint pen 2 shaft cylinder 21 Front end hole 3 Cursive 4 Ballpoint pen tips 4a Ball 41 Front cylinder part 42 Rear cylinder part 43 Mounting part 44 Backward facing step 45 Restriction wall 5 Tip holder 51 Front cylinder part 52 Rear cylinder part 53 Tsuba 54 Mounting hole 55 Contact wall part 6 Ink reservoir 7. Annular Elastic Body 8 Spring

Claims

1. A pen having a barrel and a writing element accommodated in the barrel, The writing body includes a ballpoint pen tip and a tip holding tube to which a rear end of the ballpoint pen tip is attached, The front end of the ballpoint pen tip is configured to be able to protrude outward from the front end hole of the barrel, A ballpoint pen in which, when the front end of the ballpoint pen tip is protruding outward from the front end hole of the barrel, an annular elastic body is interposed between the outer surface of the ballpoint pen tip and the inner surface of the front end hole of the barrel, The ballpoint pen tip comprises a front tube portion, the front end of which rotatably holds a ball and which protrudes forward from the front end of the tip holding tube, a rear tube portion formed rearward of the front tube portion and attached to an attachment hole at the front end of the tip holding tube, and an attachment portion formed on the outer surface between the front tube portion and the rear tube portion and to which the annular elastic body is attached, an outer diameter of the mounting portion is set to be smaller than an outer diameter of a rear end of the front tubular portion and equal to or larger than an outer diameter of the rear tubular portion, and a rearward-facing step is formed between the front tubular portion and the mounting portion; A ballpoint pen characterized in that the annular elastic body is sandwiched between the rearwardly facing step portion and the front end of the tip holding barrel in a state of being compressed in the front and rear directions.

2. 2. A ballpoint pen according to claim 1, wherein the ballpoint pen tip has a regulating wall portion, the tip holding tube has an abutting wall portion, and when the rear tube portion of the ballpoint pen tip is attached to the mounting hole of the tip holding tube, the regulating wall portion and the abutting wall portion abut in the front and rear directions.

3. 3. The ballpoint pen according to claim 2, wherein the step-shaped regulating wall portion is formed between the mounting portion of the ballpoint pen tip and the rear tube portion, and the abutment wall portion is formed on the front end of the tip holding tube or on the inner surface of the tip holding tube.

4. 3. The ballpoint pen according to claim 2, wherein the regulating wall portion is formed at the rear end of the rear tube portion of the ballpoint pen tip or on the outer surface of the rear tube portion, and the abutting wall portion is formed on the inner surface of the tip holding tube.

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