WRITING TOOL REFILL AND WRITING TOOL USING SAME

Abstract

A refill for a writing tool includes an ink containing tube that is made from a resin material and formed in a straight cylindrical shape, and a writing tip that is attached to an end of the ink containing tube. A press-fit portion, formed at the end of the ink containing tube, has a thickness being made thickened toward an inner circumferential surface and has an opening hole penetrating in an axial direction at a central portion of the press-fit portion. The writing tip or a relay member supporting the writing tip is press-fitted and attached to the press-fit portion. The refill for a writing tool can ensure a necessary and sufficient amount of ink stored without expanding an outer diameter of the ink containing tube, and sufficiently secure mechanical strength of an end portion, and a writing tool using the same can be provided.

Claims

1. A refill for a writing tool comprising: an ink containing tube that is made from a resin material and formed in a straight cylindrical shape; and a writing tip which is attached to an end of the ink containing tube, wherein a press-fit portion, of which thickness is made thickened toward an inner circumferential surface and which has an opening hole penetrating therethrough in an axial direction at a central portion of the press-fit portion, is formed at the end of the ink containing tube, and the writing tip or a relay member supporting the writing tip is press-fitted and attached to the press-fit portion.

2. The refill for a writing tool according to claim 1, wherein the press-fit portion is formed at each of both ends of the ink containing tube.

3. The refill for a writing tool according to claim 1, wherein an abutment portion in which a shaft hole having a smaller diameter than the opening hole is bored is formed closer to the central portion of the ink containing tube in the press-fit portion.

4. The refill for a writing tool according to claim 1, wherein the press-fit portion is integrally formed with the ink containing tube.

5. A writing tool that contains the refill for a writing tool in a barrel, according to claim 1.

6. The refill for a writing tool according to claim 2, wherein an abutment portion in which a shaft hole having a smaller diameter than the opening hole is bored is formed closer to the central portion of the ink containing tube in the press-fit portion.

7. The refill for a writing tool according to claim 2, wherein the press-fit portion is integrally formed with the ink containing tool.

8. The refill for a writing tool according to claim 3, wherein the press-fit portion is integrally formed with the ink containing tool.

9. A writing tool that contains the refill for a writing tool in a barrel according to claim 2.

10. A writing tool that contains the refill for a writing tool in a barrel according to claim 3.

11. A writing tool that contains the refill for a writing tool in a barrel according to claim 4.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is an external view illustrating a first aspect of a refill for a writing tool according to the present invention.

[0024] FIG. 2 is a central sectional view of the refill for a writing tool illustrated in FIG. 1.

[0025] FIG. 3 is an enlarged central sectional view illustrating an ink containing tube, as a single unit, to be used in the refill illustrated in FIG. 1.

[0026] FIG. 4 is a schematic view illustrating a first means for forming a thick press-fit portion at an end of the ink containing tube.

[0027] FIG. 5 is a schematic view similarly illustrating a second means.

[0028] FIG. 6 is a schematic view similarly illustrating a third means.

[0029] FIG. 7 is a schematic view similarly illustrating a fourth means.

[0030] FIG. 8 is an external view illustrating a second aspect of the refill for a writing tool according to the present invention.

[0031] FIG. 9 is a central sectional view of the refill for the writing tool illustrated in FIG. 8.

[0032] FIG. 10 is an enlarged central sectional view illustrating a configuration of an ink containing tube, as a single unit, to be used in the refill illustrated in FIG. 8.

[0033] FIG. 11 is an external view illustrating a state where a refill for a writing tool according to the present invention is used in a composite writing tool.

[0034] FIG. 12 is a central cross-sectional view of the composite writing tool illustrated in FIG. 11.

[0035] FIG. 13 is an enlarged external view illustrating a combined configuration of a slider employed in a composite writing tool and a refill for a writing tool.

[0036] FIG. 14 is a central cross-sectional view illustrating an example of a conventional refill for a writing tool.

DESCRIPTION OF EMBODIMENTS

[0037] A refill for a writing tool and a writing tool according to the present invention will be described based on embodiments shown in the drawings, in which, for examples, a ballpoint pen refill and a composite writing tool containing plural ballpoint pen refills in a barrel are illustrated.

[0038] First, FIGS. 1 to 3 illustrate a first embodiment of the ballpoint pen refill; a joint member 3 on which a ballpoint pen tip 2 has been mounted in advance is attached press-fittedly to one end (front end) of an ink containing tube 1 made from a resin material, for example, polypropylene.

[0039] The ink containing tube 1 is formed into a flush cylindrical shape in an axial direction, and press-fit portions 1a each of which is formed to be thickened toward an inner circumferential surface are formed at both ends of the ink containing tube 1 as illustrated in an enlarged view of both the ends in FIG. 3.

[0040] The press-fit portion 1a is constituted with an opening hole penetrating therethrough in the axial direction at a central portion, formed to be thickened. The joint member 3 is press-fitted by using the thick press-fit portion 1a, and the ballpoint pen tip 2 is attached to the front end of the ink containing tube 1 with the joint member 3.

[0041] In addition, the ballpoint pen tip 2 may be directly press-fitted and attached to the front end of the ink containing tube 1 without a relay member such as the joint member 3.

[0042] Incidentally, each of the thick press-fit portions 1a formed at both the ends of the ink containing tube 1 is formed integrally with the ink containing tube 1 in the examples illustrated in FIGS. 1 to 3.

[0043] Since the press-fit portion 1a formed at the end of the ink containing tube 1 is formed to be thickened toward the inner circumferential surface according to the ballpoint pen refill illustrated in this example, it is possible to sufficiently ensure the mechanical strength of the attachment portion of the ballpoint pen tip 2. The thickness of the press-fit portion 1a is preferably 0.5 mm or more.

[0044] Thus, it is possible to set the tube thickness of the ink containing tube 1 excluding the press-fit portion 1a relatively thin as compared with the conventional example illustrated in FIG. 14. The tube thickness can be made less than 0.5 mm, thinner than the thickness of the press-fit portion 1a. In particular, the tube thickness is preferably 0.25 mm to 0.45 mm in consideration of the moldability of the press-fit portion 1a and the like. As a result, it is possible to provide the ballpoint pen refill capable of sufficiently ensuring the ink storage amount without expanding the outer diameter of the ink containing tube 1. A length A in the axial direction of the press-fit portion 1a is preferably 1.5 mm to 5 mm from the viewpoint of ensuring an appropriate press-fitting force and ensuring the ink amount, and then, gripping force of a attaching portion to the ballpoint pen tip 2 or the joint member 3 is preferably 9.8 N or more. As for the strength of the attachment portion, a force required to pull out the ballpoint pen tip 2 or the joint member 3 attached to the press-fit portion 1a from the ink containing tube 1 is measured with a commercially available push pull gauge (a force gauge 500N manufactured by IMADA Co., Ltd.)

[0045] The outer diameter of the ink containing tube 1 is preferably 2.8 mm to 3.5 mm, which enables use without feeling any difference from the conventional writing tool.

[0046] FIG. 4(A) and (B) illustrates a first means for forming the above-described press-fit portion 1a at the end of the ink containing tube 1. The method of forming the press-fit portion 1a illustrated in FIG. 4(A) and (B) is called an impulse welding (IPW); this uses a welding tip 11 for heating and melting the end of the ink containing tube 1.

[0047] That is, an annular recess 11a into which the end of the ink containing tube 1 can be inserted is formed in the welding tip 11, and it is configured such that a heating element (not shown) is mounted to the welding tip 11 to make the welding tip 11 heated by, for example, Joule heat. In addition, a gas introduction hole 11b is formed in a central portion of the welding tip 11, and it is configured such that a cooling gas (air) can be introduced through this gas introduction hole 11b.

[0048] FIG. 4(A) illustrates a state where the end of the ink containing tube 1 is inserted into the annular recess 11a of the welding tip 11. In this state, the welding tip 11 is heated, and accordingly, the end of the ink containing tube 1 made of resin material is softened and melted. As illustrated in FIG. 4(B), the thick press-fit portion 1a is formed toward the inner circumferential surface at the end of the ink containing tube 1 along the annular recess 11a of the welding tip 11 by softening and melting the end of the ink containing tube 1.

[0049] In this state, heating of the welding tip 11 is stopped; the end of the ink containing tube 1 is cooled by feeding the cooling air into the through hole 11b in the direction indicated by the arrow. Then, the thick press-fit portion 1a is formed at the end of the ink containing tube 1, and is released from the welding tip 11.

[0050] It is possible to obtain the ink containing tube 1 at both end of which the thick press-fit portions 1a are integrally formed by performing the same process to the other end of the ink containing tube 1 as necessary.

[0051] FIG. 5 illustrates a second means for forming the press-fit portion 1a at the end of the ink containing tube 1. In the example illustrated in FIG. 5, the press-fit portions 1a formed as separate members are attached to both the ends of the ink containing tube 1, respectively, and this example adopts means for attaching the press-fit portion 1a using an adhesive.

[0052] In addition, thermal welding may enable to form the thick press-fit portions 1a to be substantially integrated with the ink containing tube 1 by attaching the press-fit portions 1a to both the ends of the ink containing tube 1 by thermal welding.

[0053] FIG. 6 illustrates a third (A means for forming the press-fit portion 1a at the end of the ink containing tube 1. The example illustrated in FIG. 6 illustrates an example of molding which employs upper and lower split molds 13 and 14 and first and second core pins 15 and 16. That is, the ink containing tube 1 is formed with the upper and lower split molds 13 and 14 and the first core pin 15, and the thick press-fit portion 1a is formed with the upper and lower split molds 13 and 14 and the second core pin 16. In this case, the press-fit portion 1a can be molded integrally with the ink containing tube 1 at the same time.

[0054] The press-fit portion 1a is formed only on one end side of the ink containing tube 1 in the example shown in FIG. 6.

[0055] FIG. 7 illustrates a fourth means for forming the press-fit portion 1a at the end of the ink containing tube 1. In the example illustrated in FIG. 7, a three-dimensional printer is used; as material (filaments) discharged from a reciprocating printer head 18 is stacked layer by layer and it is possible to integrally form the ink containing tube 1 and the press-fit portion 1a simultaneously.

[0056] FIGS. 8 to 10 illustrate a second aspect of the refill for a writing tool (ballpoint pen refill) according to the present invention. The ballpoint pen tip 2 is directly press-fitted and attached to a front end of the ink containing tube 1 without a relay member interposed therebetween in the ballpoint pen refill illustrated in FIGS. 8 to 10.

[0057] The ink containing tube 1 in the second aspect is also formed in a cylindrical shape to be flush in the axial direction. The press-fit portions 1a each of which is formed to be thickened toward an inner circumferential surface and has an opening hole penetrating in the axial direction are formed at both ends of the ink containing tube 1, respectively, as shown in FIG. 10.

[0058] In the second aspect, at the press-fit portion 1a, placed at the front end of the ink containing tube 1, to which the ballpoint pen tip 2 is to be attached, an abutment portion 1b having a shaft hole 1c is additionally formed closer to the central portion of the ink containing tube 1. The diameter of the shaft hole is smaller than the diameter of the opening hole forming the press-fit portion 1a.

[0059] Since the abutment portion 1b serves a positioning function as a stopper on which a rear end of the ballpoint pen tip 2 abuts, the ballpoint pen tip 2 formed in a tubular shape, as shown in FIG. 9, can be press-fitted to the press-fit portion 1a without forming a stepped portion, abutting on the end of the ink containing tube 1, on an outer peripheral surface of the ballpoint pen tip 2.

[0060] Also in the case of the ink containing tube 1 used for the ballpoint pen refill shown in FIGS. 8 to 10, it is possible to form the press-fit portion 1a and the abutment portion 1b at the end of the ink containing tube 1 by properly adopting the above described means shown in FIGS. 4 to 7.

[0061] FIGS. 11 to 13 illustrate an example in which the refill for a writing tool (ballpoint pen refill) according to the present invention is used in a composite multi-color ballpoint pen.

[0062] The composite multi-color ballpoint pen has an outer shell formed of a front shaft 21 and a rear shaft 22; a distal end of the front shaft 21 is reduced in diameter to form a conical shape and has a distal end opening 23. Further, it is configured such that the writing tip (ballpoint pen tip) 2 of one of the ballpoint pen refills is selectively fed out from the distal end opening 23.

[0063] A plurality of (four in this example) guiding slits 24 is formed at a rear end of the rear shaft 22 in the axial direction.

[0064] An operating portion 25a, formed on a slider 25, is disposed in each of the guiding slits 24 so as to protrudes to the outside of the rear shaft and be slidable in the axial direction. Further, an inner tubular member 27 is accommodated in the rear shaft 22 in which the guiding slit 24 is formed, and a locking face 27a, for example, to lock the slider 25 in an advanced state is formed in the inner tubular member 27.

[0065] In addition, a rear end of the inner tubular member 27 is formed to have a slightly smaller diameter and protrudes from the rear end of the rear shaft 22. A cap member 29 integrally formed with a clip 28 is fittedly attached so as to cover such a protruding portion of the inner tubular member 27.

[0066] As illustrated in FIG. 13, a front end of the slider 25 is mounted and attached to the thick press-fit portion 1a that is formed at the rear end of the ink containing tube 1 (see FIGS. 2 and 3), and a return spring (not shown) is disposed so as to surround each of the ink containing tubes 1 and the corresponding slider 25. As a result, the respective ink containing tubes 1 and sliders 25 are disposed in a state of being biased toward the rear side in the axial direction of the composite multi-color ballpoint pen.

[0067] When any one of the sliders 25 is moved forward using the operating portion 25a in the above state, the operating portion 25a of the slider 25 moves forward along a groove formed in the inner tubular member 27 and falls down in a core axis direction. As a result, a rear end locking portion 25b of the slider 25 is locked to the locking face 27a formed in the inner tubular member 27. At this time, the refill attached to the slider 25 moderately bends due to its own flexibility, and the ballpoint pen tip 2 at the distal end of the refill is held in a protruded state from the distal end opening 23.

[0068] In addition, when another second slider 25 is moved forward in this state, a lock release cam 25c formed on the second slider 25 abuts on a pressed protrusion 25b of the first slider 25 that has been already locked in the advancing state and pushes the rear end locking portion 25b of the first slider 25 to the outside. As a result, the locking state of the first slider 25 is released.

[0069] As a result, the first slider 25 moves backward by action of the above-described return spring, and the rear end locking portion 25b of the second slider 25 is locked to the locking face 27a formed on the inner tubular member 27, thereby performing exchange of the ballpoint pen tip 2 fed out from the distal end opening 23.

[0070] As regards the refill for a writing tool and the writing tool according to the present invention as described above, since the tube thickness of the ink containing tube 1 can be made relatively thin except for the press-fit portion 1a at the end, it is possible to provide the refill for a writing tool ensuring a sufficient amount of ink stored without expanding the outer diameter of the ink containing tube.

[0071] Further, flexibility is imparted to the whole part of the refill for a writing tool by forming the thickness of the ink containing tube to be relatively thin; it is possible to guarantee a smooth protruding and retracting operation of each writing tip by utilizing the flexibility when this refill is used in the above-described composite writing tool.

[0072] Although the ballpoint pen refill is exemplified as the embodiment in the above description, the present invention can also be applied to a refill for a writing tool provided with a tip other than the ballpoint pen tip, and the same operational effects as described above can be obtained.

REFERENCE SIGNS LIST

[0073] 1 ink containing tube [0074] 1a press-fit portion (opening hole) [0075] 1b abutment portion [0076] 1c shaft hole [0077] 2 writing tip (ballpoint pen tip) [0078] 3 joint member [0079] 11 welding tip [0080] 11a annular recess [0081] 11b gas inlet hole [0082] 13 upper split die [0083] 14 lower split die [0084] 15 first core pin [0085] 16 second core pin [0086] 18 printer head [0087] 21 front shaft [0088] 22 rear shaft [0089] 24 guiding slit [0090] 25 slider [0091] 25a operating portion