Writing instrument part and method for manufacturing writing instrument part

Abstract

To prevent a material forming a part having no functional part from leaking to a functional portion in a writing instrument part composed of two parts made of different materials.SOLUTION: There is provided a writing instrument part composed of a covering portion, which is a part formed of synthetic resins of different materials, and an embedded portion partially covered by the covering portion. The functional portion, which is part of the embedded portion, protrudes from the supporting surface, which is part of the covering portion. A sealing surface, which is part of the embedded portion, is formed on the peripheral edge of the functional portion. The sealing surface forms a continuous surface with the supporting surface.SELECTED DRAWING: Figure 1G

Description

[Technical Field]

[0001] The present invention relates to a writing implement component that constitutes a part of a writing implement and a method for manufacturing the same. [Background technology]

[0002] Patent Document 1 discloses a technology for forming a lead-advancing knock, which is a component for advancing a desired pen lead in a knock-type multicolor pen, by two-color molding. The lead-advancing knock formed by this two-color molding has a two-layer structure consisting of a colored, transparent outer piece located on the outside and a white, opaque inner piece located on the inside. In other words, the lead-advancing knock disclosed in Patent Document 1 is configured so that the entire outer surface is colored.

[0003] Patent Document 2 discloses a technique for forming a pusher, which is operated to advance or retract the writing part in a multi-colored retractable writing instrument, as a separate part consisting of a pusher body and a color identification part of a different color from the pusher body, and then fitting the color identification part into the pusher body. However, the color identification part is a very small part compared to the pusher body, making it difficult to attach by hand. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Utility Model Registration No. 3183953 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-183818 Summary of the Invention [Problem to be solved by the invention]

[0005] When synthetic resin parts such as the knock rod used in knock-type ballpoint pens are formed by two-color molding, and part of the primary molded product is configured as a part (hereinafter referred to as the "functional part") that has some function in the writing instrument (for example, a cam mechanism in the knock rod), there is a concern that the resin injected during secondary molding may leak into the functional part through gaps created by shrinkage of the primary molded product, causing a change in the shape of the functional part and impairing its function.

[0006] Therefore, an object of the embodiment of the present application is to prevent the material forming the part that does not have a functional part from leaking into the functional part in a writing implement part that is composed of two parts made of different materials. [Means for solving the problem]

[0007] In view of the above problems, the writing instrument part according to the embodiment of the present application is composed of a covering portion, which is a part formed of synthetic resins of different materials, and an embedded portion, a part of which is covered by the covering portion, and a functional portion, which is part of the embedded portion, protrudes from a support surface, which is part of the covering portion, and a sealing surface, which is part of the embedded portion, is formed around the periphery of the functional portion, and the sealing surface forms a continuous surface with the support surface.

[0008] The covering portion and the embedded portion are made of different synthetic resins, which not only include different resin types (e.g., polycarbonate and thermoplastic elastomer), but also the same resin type but different colors (e.g., ABS).

[0009] It is preferable that the embedded portion has a flange portion having the sealing surface, and the functional portion protrudes from the sealing surface.

[0010] In addition, the manufacturing method of a writing instrument part according to an embodiment of the present application is a two-color molding method in which the embedded portion of the writing instrument part is formed by primary molding and the covering portion is formed by secondary molding, and the embedded portion is formed by injection molding into a primary cavity formed by a movable mold and a primary molding mold, and the edge of the movable mold at the dividing surface of the primary cavity is surrounded by the edge of the primary molding mold at the dividing surface, and the sealing surface is formed between the edge of the movable mold and the edge of the primary molding mold.

[0011] It is desirable that the sealing surface be pressed against the movable mold at the parting surface between the movable mold and the secondary molding mold during the secondary molding.

[0012] Furthermore, in a writing instrument in which a plurality of refills are accommodated in a barrel, the writing instrument part is preferably a knock rod attached to the rear end of each of the plurality of refills, and the knock rod has a convex curved surface that protrudes toward the axis at an attachment portion for the rear end of the refill, which is formed at the tip of the knock rod. [Effects of the Invention]

[0013] With the above-described configuration, the embodiment of the present application makes it possible to prevent the material forming the part that does not have a functional part from leaking into the functional part in a writing instrument part that is composed of two parts made of different materials.

[0014] Furthermore, when the writing instrument part is a knock rod attached to the rear end of each of the refills in a writing instrument that stores multiple refills in a barrel, a convex curved surface is formed at the tip of the knock rod at the attachment portion to the rear end of the refill, so that the bottom side of the refill can be directed toward the outer periphery, thereby preventing poor dispensing of the refill. [Brief explanation of the drawings]

[0015] [Figure 1A] FIG. 2 is a front external perspective view of the writing implement component of the first embodiment. [Figure 1B]FIG. 1B is a front view of the writing instrument component of FIG. 1A. [Figure 1C] FIG. 1B is a rear view of the writing instrument component of FIG. 1A. [Figure 1D] FIG. 1B is a right side view of the writing instrument component of FIG. 1A. [Figure 1E] FIG. 1B is a bottom view of the writing instrument component of FIG. 1A. [Figure 1F] FIG. 1B is a plan view of the writing instrument component of FIG. 1A. [Figure 1G] 1B and 1C. FIG. [Figure 2A] 1B is a front external perspective view of an embedded portion constituting the writing implement component of FIG. 1A. FIG. [Figure 2B] 2B is a rear inner perspective view of the embedded portion of FIG. 2A. [Figure 2C] FIG. 2B is a front view of the buried part of FIG. 2A. [Figure 2D] FIG. 2B is a rear view of the buried portion of FIG. 2A. [Figure 2E] FIG. 2B is a right side view of the buried portion of FIG. 2A. [Figure 2F] 2B is a bottom view of the buried portion of FIG. 2A. [Figure 2G] FIG. 2B is a plan view of the embedded portion of FIG. 2A. [Figure 2H] 2C and 2D. FIG. [Figure 3A] FIG. 1B is a front view of a covering portion that constitutes the writing implement part of FIG. 1A. [Figure 3B] FIG. 3B is a rear view of the covering portion of FIG. 3A. [Figure 3C] FIG. 3B is a right side view of the covering portion of FIG. 3A. [Figure 3D] 3B is a cross-sectional view taken along line III-III shown in FIG. 3A and FIG. 3B. [Figure 4A] 1B is a cross-sectional view showing a mold before primary molding in two-color molding of the writing implement part of FIG. 1A. [Figure 4B] An enlarged view of the primary cavity periphery in Figure 4A. [Figure 4C] 1B is a cross-sectional view showing a mold after primary molding in two-color molding of the writing implement part of FIG. 1A. [Figure 5A] FIG. 1B is a cross-sectional view showing a mold before secondary molding in two-color molding of the writing instrument part of FIG. 1A. [Figure 5B]1B is a cross-sectional view showing the mold after secondary molding in the two-color molding of the writing implement part of FIG. 1A. [Figure 6] FIG. 10 is a front external perspective view of a writing implement component according to a modified example of the first embodiment. [Figure 7A] FIG. 10 is a front external perspective view of a writing implement part according to a second embodiment. [Figure 7B] 7B is a rear, exterior perspective view of the writing instrument component of FIG. 7A. FIG. [Figure 7C] FIG. 7B is a front view of the writing instrument component of FIG. 7A. [Figure 7D] FIG. 7B is a plan view of the writing instrument component of FIG. 7A. [Figure 7E] Cross-sectional view taken along line VII-VII shown in FIG. 7C. [Figure 8A] 7B is a front external perspective view of an embedded portion constituting the writing implement component of FIG. 7A. FIG. [Figure 8B] 8B is a rear-exterior perspective view of the embedded portion of FIG. 8A. [Figure 8C] FIG. 8B is a front view of the buried part of FIG. 8A. [Figure 8D] FIG. 8B is a plan view of the embedded portion of FIG. 8A. [Figure 8E] 8C is a cross-sectional view taken along the line VIII-VIII in FIG. 8C. [Figure 9A] 7B is a front external perspective view of a covering portion that constitutes the writing implement component of FIG. 7A. FIG. [Figure 9B] 9B is a rear outward perspective view of the covering portion of FIG. 9A. FIG. [Figure 9C] FIG. 9B is a front view of the covering portion of FIG. 9A. [Figure 9D] FIG. 9B is a plan view of the covering portion of FIG. 9A. [Figure 9E] 9C is a cross-sectional view taken along the line IX-IX in FIG. 9C. [Figure 10A] 7B is a cross-sectional view showing a mold before primary molding in two-color molding of the writing implement part of FIG. 7A. [Figure 10B] An enlarged view of the primary cavity periphery in Figure 10A. [Figure 10C] 7B is a cross-sectional view showing the mold after primary molding in two-color molding of the writing implement part of FIG. 7A. [Figure 11A] FIG. 7B is a cross-sectional view showing a mold before secondary molding in two-color molding of the writing implement part of FIG. 7A. [Figure 11B]7B is a cross-sectional view showing the mold after secondary molding in the two-color molding of the writing implement part of FIG. 7A. [Figure 12A] FIG. 10 is a front outer perspective view of a writing implement part according to a third embodiment. [Figure 12B] FIG. 12B is a front interior perspective view of the writing instrument component of FIG. 12A. [Figure 12C] FIG. 12B is a front view of the writing instrument component of FIG. 12A. [Figure 12D] FIG. 12B is a right side view of the writing instrument component of FIG. 12A. [Figure 12E] XII-XII cross section shown in Figure 12C. [Figure 13A] 12B is a front external perspective view of an embedded portion constituting the writing implement component of FIG. 12A. FIG. [Figure 13B] FIG. 13B is a front inner perspective view of the embedded part of FIG. 13A. [Figure 13C] FIG. 13B is a front view of the buried part of FIG. 13A. [Figure 13D] 13B is a right side view of the buried portion of FIG. 13A. [Figure 13E] XIII-XIII cross-sectional view shown in FIG. 13C. [Figure 14A] 12B is a front external perspective view of a covering portion that constitutes the writing implement component of FIG. 12A. FIG. [Figure 14B] FIG. 14B is a front inner perspective view of the covering portion of FIG. 14A. [Figure 14C] FIG. 14B is a front view of the covering portion of FIG. 14A. [Figure 14D] FIG. 14B is a rear view of the covering portion of FIG. 14A. [Figure 14E] FIG. 14B is a right side view of the covering portion of FIG. 14A. [Figure 14F] XIV-XIV cross-sectional view shown in Figures 14C and 14D. [Figure 15A] 12B is a cross-sectional view showing a mold before primary molding in two-color molding of the writing implement part of FIG. 12A. [Figure 15B] An enlarged view of the primary cavity periphery of Figure 15A. [Figure 15C] 12B is a cross-sectional view showing the mold after primary molding in two-color molding of the writing implement part of FIG. 12A. [Figure 16A] 12B is a cross-sectional view showing a mold before secondary molding in two-color molding of the writing implement part of FIG. 12A. [Figure 16B]12B is a cross-sectional view showing the mold after secondary molding in the two-color molding of the writing implement part of FIG. 12A. [Figure 17A] FIG. 1 is a front view of a writing instrument equipped with each of the writing instrument components according to the first to third embodiments. [Figure 17B] 17B is a cross-sectional view taken along the line XVII-XVII in FIG. 17A. [Figure 18A] 17B shows the writing instrument of FIG. 17A as viewed slightly to the right. [Figure 18B] 18B is a cross-sectional view taken along the line XVIII-XVIII in FIG. 18A. [Figure 19] FIG. 1 is a perspective view showing the rear end portion of a writing instrument equipped with the writing instrument parts of the first to third embodiments. [Figure 20A] FIG. 10 is a front external perspective view of a writing implement part according to a fourth embodiment. [Figure 20B] FIG. 20B is a front view of the writing instrument component of FIG. 20A. [Figure 20C] FIG. 20B is a rear view of the writing instrument component of FIG. 20A. [Figure 20D] FIG. 20B is a right side view of the writing instrument component of FIG. 20A. [Figure 20E] 20B is a bottom view of the writing instrument component of FIG. 20A. [Figure 20F] FIG. 20B is a plan view of the writing instrument component of FIG. 20A. [Figure 20G] 20B and 20C. [Figure 21A] FIG. 10 is a right side view of the writing instrument component of the fourth embodiment attached to the refill. [Figure 21B] FIG. 10 is a cross-sectional view of a writing instrument component according to a fourth embodiment attached to a refill. [Figure 21C] FIG. 10 is a partially enlarged cross-sectional view of a writing instrument component according to a fourth embodiment attached to a refill. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present application will be described with reference to the drawings. Reference numerals commonly used in the drawings indicate corresponding parts even if not specifically mentioned in the description of each drawing. In the drawings described below, the tip side of the writing instrument 100 shown in FIG. 17A will be referred to as the "bottom surface," the rear end side as the "flat surface," the outer surface side as the "front surface," and the inner surface side as the "back surface." Furthermore, the right side as viewed from the "front surface" will be referred to as the "right side surface."

[0017] (1) First embodiment The writing instrument component 10 of the first embodiment of the present application is configured as a knock bar 11, as shown in the front outer perspective view of FIG. 1A, the front view of FIG. 1B, the rear view of FIG. 1C, the right side view of FIG. 1D, the bottom view of FIG. 1E, the plan view of FIG. 1F, and FIG. 1G, which is a cross-sectional view II of FIG. 1A.

[0018] This knock bar 11 is generally rod-shaped, and its longitudinal direction coincides with the longitudinal direction of a window hole 131 (see Figures 17A, 17B, 18A, and 18B) of the writing instrument 100, which will be described later. When attached to the writing instrument 100, the knock bar 11 has an outer portion 40 located on the outside and an inner portion 41 located on the inside. That is, the knock bar 11 has a structure in which the inner portion 41, which is narrower than the outer portion 40, protrudes from a support surface 22 (Figures 1C, 1D, 1E, and 1F) that forms the inner side of the outer portion 40. This support surface 22 is formed as an inner step 42, which is a step between the outer portion 40 and the inner portion 41.

[0019] The rear end of the knock bar 11 is formed as a knock protrusion 43 that protrudes outward. The front half of the outer portion 40 has wing-like portions 45 that protrude longitudinally on both sides and are wider than the rear half. The rear ends of the wing-like portions 45 form rear steps 46. Meanwhile, the front end of the knock bar 11 forms a spring insertion portion 48 whose width and height are reduced via a front step 47. Furthermore, the front end of the spring insertion portion 48 forms a refill attachment portion 49 whose width and height are also reduced. A spring 150 (see FIGS. 17B and 18B), which will be described later, is inserted around the outer periphery of the spring insertion portion 48, and the rear end of the inserted spring 150 abuts against the front steps 47. The refill attachment portion 49 is inserted into the rear end of a refill 200 (see FIGS. 17B and 18B), which will be described later.

[0020] As shown in FIG. 1G, the knock bar 11 is formed by two-color molding of an embedded portion 30 as a primary molded body and a covering portion 20 as a secondary molded body. The covering portion 20 and the embedded portion 30 are formed from different materials, specifically synthetic resins of different colors. A portion of the embedded portion 30 is covered by the housing portion 21 of the covering portion 20. A display portion 35, which is a portion of the embedded portion 30, is exposed from an indicator groove 44, which is a groove formed in the knock protrusion 43 (FIGS. 1A, 1B, 1D, 1E, and 1F).

[0021] Meanwhile, on the inner surface of the rear end of the knock bar 11, an inner portion 41 protrudes from the support surface 22 (inner step 42). A locking projection 50 is formed near the rear end of this inner portion 41 as the functional portion 33 of the embedded portion 30. In front of this locking projection 50, a release projection 51 is formed as part of the covering portion 20. Furthermore, in front of this release projection 51, two recesses 52 are formed.

[0022] The embedded portion 30 constituting the knock bar 11 of this embodiment is shown in a front outer perspective view ( FIG. 2A ), a rear inner perspective view ( FIG. 2B ), a front view ( FIG. 2C ), a rear view ( FIG. 2D ), a right side view ( FIG. 2E ), a bottom view ( FIG. 2F ), a plan view ( FIG. 2G ), and a cross-sectional view taken along the lines II-II of FIGS. 2C and 2D ( FIG. 2H ). The embedded portion 30 is composed of a base-shaped flange portion 31 that extends inward, a protruding portion 34 that protrudes outward from the flange portion 31, a sealing surface 32 that is the inner surface of the flange portion 31, and a functional portion 33 that functions as an inner portion 41 that protrudes inward from the sealing surface 32 and is surrounded by the sealing surface 32. The functional portion 33 functions as a locking projection 50 of the knock bar 11 (see FIGS. 1A , 1D to 1G ). The flange 31 and the protruding portion 34 are portions that are housed in the housing portion 21 (see FIG. 1G) of the covering portion 20. The outer edge of the protruding portion 34 forms an indicator portion 35 that is exposed from an indicator groove 44 (see FIGS. 1A and 1B) of the knock bar 11.

[0023] On the other hand, on the inner surface side of the flange portion 31, the peripheral portion surrounding the inside portion 41 forms a sealing surface 32 (see FIGS. 2B and 2D). This sealing surface 32 forms a continuous surface with the support surface 22 of the knock bar 11, as shown in FIGS. 1C and 1G.

[0024] The cover 20 constituting the knock bar 11 of this embodiment is shown in a front view ( FIG. 3A ), a rear view ( FIG. 3B ), a right side view ( FIG. 3C ), and a cross-sectional view ( FIG. 3D ) taken along the line III-III of FIGS. 3A and 3B. The cover 20 is generally rod-shaped, and its longitudinal direction coincides with the longitudinal direction of the window hole 131 (see FIGS. 17A , 17B , 18A , and 18B ) of the writing instrument 100 (described below). The cover 20 has an outer portion 40 located on the outside when attached to the writing instrument 100, and an inner portion 41 located on the inside. That is, the cover 20 has a structure in which the inner portion 41, which is narrower than the outer portion 40, protrudes from a support surface 22 ( FIG. 3B ) that forms the inner side of the outer portion 40. This support surface 22 is formed as an inner step 42, which is a step between the outer portion 40 and the inner portion 41. The rear end side of the covering portion 20 is formed as a knock protrusion 43 that protrudes outward. An indication groove 44 is formed on the outer surface of the knock protrusion 43.

[0025] The front half of the outer part 40 has wing-like parts 45 that protrude longitudinally on both sides and are wider than the rear half. The rear ends of the wing-like parts 45 form rear steps 46. Meanwhile, the tip of the covering part 20 forms a spring outer fitting part 48 with a reduced width and height via a front step 47. Furthermore, the tip of the spring outer fitting part 48 forms a refill attachment part 49 with a reduced width and height.

[0026] Meanwhile, an inner portion 41 protrudes from the support surface 22 (inner step 42) on the inner surface side of the covering portion 20. A release protrusion 51 is formed near the rear end of this inner portion 41. Furthermore, two recesses 52 are formed in front of this release protrusion 51. Also, an accommodation portion 21 that accommodates the flange portion 31 and protrusion portion 34 of the embedded portion 30 is formed on the rear end side of the covering portion 20.

[0027] The knock rod 11 of this embodiment is formed by two-color molding of two types of synthetic resin. Specifically, the embedded portion 30 is formed by primary molding, and the covering portion 20 is formed by secondary molding. As a result, the flange portion 31 and the protruding portion 34 of the embedded portion 30 are embedded in the housing portion 21 of the covering portion 20 (see FIG. 1G). A method for manufacturing this knock rod 11 will be described with reference to FIGS. 4A to 4C and 5A and 5B.

[0028] 4A is a cross-sectional view showing the molds before primary molding, illustrating a state in which a movable mold 500 and a primary molding mold 600 are joined together. A cavity corresponding to the inner portion 41 of the knock bar 11 is formed in the movable mold 500, and a primary gate 515 through which the primary molding resin is injected from a primary runner 510 and a secondary gate 525 through which the secondary molding resin is injected from a secondary runner 520 are opened in this cavity. Meanwhile, a cavity corresponding to the flange portion 31 and the protruding portion 34 of the embedded portion 30 is formed in the primary molding mold 600, and this cavity and a part of the cavity of the movable mold 500 form a primary cavity 610. In this state, as shown in the enlarged view of FIG. 4B, an edge Q of the movable mold 500 at the parting surface P1 of the primary cavity 610 is surrounded by an edge R of the primary molding mold 600 at this parting surface P1.

[0029] Fig. 4C shows a state in which primary molding resin is injected from primary runner 510 through primary gate 515 into primary cavity 610 shown in Fig. 4A. In this state, primary cavity 610 is filled with primary molding resin, which cools and solidifies, thereby injection-molding embedded portion 30 shown in Figs. 2A to 2H. In this state, sealing surface 32 is formed on the inner surface side of flange portion 31 as a region between the edge of movable mold 500 and the edge of primary molding mold 600.

[0030] 5A shows a state in which the movable mold 500, together with the embedded portion 30, has been separated from the primary molding mold 600 from the state shown in FIG. 4C and joined to the secondary molding mold 700. A cavity corresponding to the outer portion 40 of the knock bar 11 is formed in the secondary molding mold 700, and this cavity and the cavity on the movable mold 500 side form a secondary cavity 710. This secondary cavity 710 surrounds the flange portion 31 of the embedded portion 30. In this state, the sealing surface 32 of the flange portion 31 is in close contact with the parting surface P2 between the movable mold 500 and the secondary molding mold 700.

[0031] FIG. 5B shows a state in which secondary molding resin is injected from secondary runner 520 through secondary gate 525 into secondary cavity 710 shown in FIG. 5A. In this state, secondary cavity 710 is filled with secondary molding resin, which cools and solidifies, and covering portion 20 shown in FIGS. 3A to 3D is injection molded in a state in which it encloses embedded portion 30. Here, sealing surface 32 of embedded portion 30 is pressed against movable mold 500 at the parting surface between movable mold 500 and secondary molding mold 700. Therefore, sealing surface 32 prevents secondary molding resin from leaking into functional portion 33 (see FIG. 2E), and as a result, deformation of the shape of functional portion 33 by the secondary molding resin is avoided.

[0032] Here, when the knock rods 11 serving as the writing instrument component 10 are used in a multi-color ballpoint pen serving as the writing instrument 100, each knock rod 11 is attached to a ballpoint pen refill containing a different color of ink. The knock rods 11 can be formed by using synthetic resin of the same color for the covering portion 20, and synthetic resin of a color corresponding to each ink for the embedded portion 30. This makes it possible to display the ink color of the ballpoint pen refill by the display portion 35 of the embedded portion 30.

[0033] The knock bar 11 serving as the writing instrument component 10 of this embodiment can also be formed as shown in a modified example in FIG. 6. In this modified example, the protruding portion 34 of the embedded portion 30 formed in the primary molding is formed lower, so that the indicator 35 is recessed from the surface of the knock protrusion 43. Forming it in this manner makes it possible to distinguish it from the knock protrusion 43 of the knock bar 11 shown in FIG. 1A by touch. This makes it possible, for example, to connect the knock bar shown in FIG. 6 to a refill with a different function (e.g., mechanical pencil refill 220) or a refill with different ink properties than the multiple ballpoint pen refills 210 in the writing instrument 100 shown in FIG. 17B (e.g., the knock bar 11 of the above-described embodiment is used for refills containing non-thermochromic ink, while the knock bar 11 of this modified example is used for refills containing thermochromic ink), allowing the user to perceive the refills as having different functions by touch.

[0034] (2) Second embodiment The writing instrument part 10 of the second embodiment of the present application is configured as a crown 12 attached to the rear end of the barrel 110 (see Figures 17A and 18A) of the writing instrument 100, as shown in the front external oblique view of Figure 7A, the rear external oblique view of Figure 7B, the front view of Figure 7C, the plan view of Figure 7D, and Figure 7E, which is a cross-sectional view taken along VII-VII of Figure 7C.

[0035] Crown 12 is composed of a substantially hemispherical exposed portion 60 and an insertion portion 61 serving as functional portion 33 that protrudes from support surface 22, which forms the bottom surface of exposed portion 60. Insertion portion 61 is formed in the shape of a hollow, substantially cylinder, and two flanges 62 are formed on its outer circumferential surface. Insertion portion 61 is the portion that is inserted into the rear end of barrel 110 of writing instrument 100 (see Figures 17B and 18B). Furthermore, exposed portion 60 is the portion that is exposed to the outside when crown 12 is attached to the rear end of barrel 110 of writing instrument 100, as shown in Figures 17A and 18A.

[0036] As shown in Fig. 7E, crown 12 is formed by two-color molding of embedded portion 30 as a primary molded body and covering portion 20 as a secondary molded body. Covering portion 20 and embedded portion 30 are formed from synthetic resins of different materials. Specifically, embedded portion 30 is formed from a synthetic resin with greater elasticity.

[0037] Embedded portion 30 constituting crown 12 of this embodiment is shown in a front outer perspective view (FIG. 8A), a rear outer perspective view (FIG. 8B), a front view (FIG. 8C), a plan view (FIG. 8D), and a cross-sectional view taken along line VIII-VIII of FIG. 8C (FIG. 8E). Embedded portion 30 is composed of a disk-shaped flange portion 31, a sealing surface 32 which is the inner surface of flange portion 31, a functional portion 33 which protrudes from sealing surface 32 and is surrounded by sealing surface 32, and a protruding portion 34 which protrudes from the top surface of flange portion 31. Protruding portion 34 is composed of a simple cylindrical portion protruding from flange portion 31 and a truncated conical portion on the rear side of this.

[0038] Covering portion 20 constituting crown 12 of the present embodiment is shown in a front outer perspective view (FIG. 9A), a rear outer perspective view (FIG. 9B), a front view (FIG. 9C), a plan view (FIG. 9D), and a cross-sectional view taken along line IX-IX of FIG. 9C (FIG. 9E). Covering portion 20 is generally hemispherical, and its bottom side is formed with housing portion 21 (see FIGS. 9A and 9E), which is a space for housing part of functional portion 33 (specifically, flange portion 31 and protrusion 34 shown in FIGS. 8A to 8E).

[0039] Here, support surface 22 (see FIG. 9A), which is the bottom surface of covering portion 20, and seal surface 32 (see FIG. 8A), which is the bottom surface of flange portion 31 of embedded portion 30, form a continuous surface in crown 12 as shown in FIG. 7A.

[0040] Crown 12 of the present embodiment is formed by two-color molding of two types of synthetic resin. Specifically, embedded portion 30 is formed by primary molding, and covering portion 20 is formed by secondary molding. As a result, flange portion 31 and protruding portion 34 of embedded portion 30 are embedded in housing portion 21 of covering portion 20 (see FIG. 7E). A method of manufacturing crown 12 will be described with reference to FIGS. 10A to 10C and 11A and 11B.

[0041] FIG. 10A is a cross-sectional view showing the mold before primary molding, showing the state in which the movable mold 500 and the primary molding mold 600 are joined. The movable mold 500 has a through-hole with a circular cross-section, into which a cylindrical core pin 530 is inserted. A cylindrical core pin outer tube 540 is inserted into the lower part of the space between the movable mold 500 and the core pin 530. In other words, the space formed by the movable mold 500, the core pin 530, and the core pin outer tube 540 forms a cavity corresponding to the functional part 33 of the embedded part 30. A gate (not shown) is provided in this cavity through which the primary molding resin is injected. The primary molding mold 600 is composed of a primary support mold 620 through which the movable mold 500 is inserted and a primary split mold 630 supported by the primary support mold 620. A cavity corresponding to the flange 31 and protrusion 34 of the embedded portion 30 is formed in this primary split mold 630, and this cavity and a part of the cavity of the movable mold 500 form the primary cavity 610. In this state, as shown in the enlarged view of Fig. 10B, the edge Q of the movable mold 500 at the parting surface P1 of the primary cavity 610 is surrounded by the edge R of the primary molding mold 600 at this parting surface P1.

[0042] Fig. 10C shows the state in which primary molding resin has been injected into primary cavity 610 shown in Fig. 10A. In this state, primary cavity 610 is filled with primary molding resin, which cools and solidifies, thereby injection-molding embedded portion 30 shown in Figs. 8A to 8E. In this state, sealing surface 32 is formed on the inner surface side of flange portion 31 as a region between the edge of movable mold 500 and the edge of primary molding mold 600.

[0043] 11A shows a state in which movable mold 500, together with embedded portion 30, has separated from primary molding mold 600 from the state shown in FIG. 10C and is joined to secondary molding mold 700. Secondary molding mold 700 is composed of secondary support mold 720, through which movable mold 500 is inserted, and secondary split mold 730, which is supported by secondary support mold 720. A cavity corresponding to the exposed portion of crown 12 is formed in secondary split mold 730, and this cavity and the cavity on the movable mold 500 side form secondary cavity 710. Secondary cavity 710 surrounds flange 31 and protruding portion 34 of embedded portion 30. In this state, sealing surface 32 of flange 31 is in close contact with parting surface P2 between movable mold 500 and secondary molding mold 700.

[0044] FIG. 11B shows a state in which secondary molding resin has been injected into secondary cavity 710 shown in FIG. 11A through a gate (not shown). In this state, secondary cavity 710 is filled with secondary molding resin, which cools and solidifies, and covering portion 20 shown in FIGS. 9A to 9E is injection molded in a state in which it encloses embedded portion 30. Here, sealing surface 32 of embedded portion 30 is pressed against movable mold 500 at the parting surface between movable mold 500 and secondary molding mold 700. Therefore, sealing surface 32 prevents secondary molding resin from leaking into functional portion 33 (see FIG. 8A), and as a result, deformation of the shape of functional portion 33 by the secondary molding resin is avoided.

[0045] (3) Third embodiment The writing instrument part 10 of the third embodiment of the present application is configured as a clip 13 that is attached near the rear end of the barrel 110 (see Figures 17A and 18A) of the writing instrument 100, as shown in the front outer oblique view of Figure 12A, the front inner oblique view of Figure 12B, the front view of Figure 12C, the right side view of Figure 12D, and Figure 12E, which is a cross-sectional view along XII-XII of Figure 12C.

[0046] This clip 13 is composed of a slightly curved, long, plate-like extension portion 71, a cylindrical fixing portion 70 that protrudes inward from the rear end of this extension portion 71, and a substantially hemispherical ball portion 73 that protrudes inward from the tip of this extension portion 71. The fixing portion 70 is the portion that is inserted into the rear end of the barrel 110 (see Figure 17B) of the writing instrument 100. The ball portion 73 is the portion that abuts against the surface of the barrel 110 (see Figure 17B) of the writing instrument 100. Furthermore, a substantially crescent-shaped display portion 35 of a different color is provided near the tip of the outer surface of the extension portion 71.

[0047] 12E, the clip 13 is formed by two-color molding of the embedded portion 30 as a primary molded body and the covering portion 20 as a secondary molded body. The covering portion 20 and the embedded portion 30 are formed from synthetic resins of different colors.

[0048] The embedded portion 30 constituting the clip 13 of this embodiment is shown in a front outer perspective view (FIG. 13A), a front inner perspective view (FIG. 13B), a front view (FIG. 13C), a right side view (FIG. 13D), and a cross-sectional view taken along line XIII-XIII of FIG. 13C (FIG. 13E). The embedded portion 30 is composed of a short rectangular prism-shaped flange portion 31, a sealing surface 32 that is the inner surface of the flange portion 31, a functional portion 33 that protrudes in a substantially hemispherical shape from the sealing surface 32 and whose periphery is surrounded by the sealing surface 32, and a protruding portion 34 that protrudes from the outer surface of the flange portion 31. The protruding portion 34 is formed in a thick, substantially crescent shape.

[0049] The covering portion 20 constituting the clip 13 of this embodiment is shown in a front outer perspective view (FIG. 14A), a front inner perspective view (FIG. 14B), a front view (FIG. 14C), a rear view (FIG. 14D), a right side view (FIG. 14E), and a cross-sectional view taken along the line XIV-XIV of FIG. 14C (FIG. 14F). The covering portion 20 is composed of a slightly curved, elongated extension portion 71 and a cylindrical fixing portion 70 protruding inward from the rear end of the extension portion 71. A housing portion 21 (see FIGS. 14B and 14F) is formed near the tip of the extension portion 71, and serves as a space for housing a portion of the functional portion 33 (specifically, the flange portion 31 and the protrusion portion 34 shown in FIGS. 8A to 8E). The housing portion 21 opens as a generally crescent-shaped display opening 72 on the outer surface of the extension portion 71.

[0050] Here, the support surface 22 (see FIG. 14B) which is the bottom surface of the covering portion 20 and the seal surface 32 (see FIG. 13B) which is the bottom surface of the flange portion 31 of the embedded portion 30 form a continuous surface in the clip 13 as shown in FIG. 12B.

[0051] The clip 13 of this embodiment is formed by two-color molding of two types of synthetic resin. Specifically, the embedded portion 30 is formed by primary molding, and the covering portion 20 is formed by secondary molding. As a result, the flange portion 31 and the protruding portion 34 of the embedded portion 30 are embedded in the housing portion 21 of the covering portion 20 (see FIG. 12F). A method for manufacturing this clip will be described with reference to FIGS. 15A to 15C and 16A and 16B.

[0052] FIG. 15A is a cross-sectional view showing the molds before primary molding, showing the state in which the movable mold 500 and the primary molding mold 600 are joined. A cavity corresponding to the ball portion 73 of the clip 13 is formed in the movable mold 500. Meanwhile, a cavity corresponding to the flange portion 31 and protrusion portion 34 of the embedded portion 30 is formed in the primary molding mold 600, and this cavity and a part of the cavity of the movable mold 500 form a primary cavity 610. The movable mold 500 is further provided with a primary gate 515 through which the primary molding resin is injected from the primary runner 510 into this primary cavity 610. The movable mold 500 also has a cavity formed therein in which the fixed portion 70 will be formed later, and this cavity opens to a secondary gate 525 through which the secondary molding resin is injected from the secondary runner 520. The movable mold 500 is further provided with secondary runners 520 and secondary gates 525 in two locations. In this state, as shown in the enlarged view of FIG. 15B, the edge Q of the movable mold 500 at the parting surface P1 of the primary cavity 610 is surrounded by the edge R of the primary molding mold 600 at this parting surface P1.

[0053] Fig. 15C shows a state in which primary molding resin is injected from primary runner 510 through primary gate 515 into primary cavity 610 shown in Fig. 15A. In this state, primary cavity 610 is filled with primary molding resin, which cools and solidifies, thereby injection-molding embedded portion 30 shown in Figs. 13A to 13E. In this state, sealing surface 32 is formed on the inner surface side of flange portion 31 as a region between the edge of movable mold 500 and the edge of primary molding mold 600.

[0054] 16A shows a state in which the movable mold 500, together with the embedded portion 30, has been separated from the primary molding mold 600 from the state shown in FIG. 15C and joined to the secondary molding mold 700. A cavity corresponding to the extension portion 71 of the clip 13 is formed in the secondary molding mold 700, and this cavity and the cavity on the movable mold 500 side form a secondary cavity 710. This secondary cavity 710 surrounds the flange portion 31 and protrusion portion 34 of the embedded portion 30. In this state, the sealing surface 32 of the flange portion 31 is in close contact with the parting surface P2 between the movable mold 500 and the secondary molding mold 700.

[0055] FIG. 16B shows a state in which secondary molding resin is injected from secondary runner 520 through secondary gate 525 into secondary cavity 710 shown in FIG. 16A. In this state, secondary cavity 710 is filled with secondary molding resin, which cools and solidifies, and covering portion 20 shown in FIGS. 14A to 14F is injection molded in a state in which it encloses embedded portion 30. Here, sealing surface 32 of embedded portion 30 is pressed against movable mold 500 at the parting surface between movable mold 500 and secondary molding mold 700. Therefore, sealing surface 32 prevents secondary molding resin from leaking into ball portion 73 (see FIG. 12B) serving as functional portion 33, and as a result, deformation of the shape of functional portion 33 by the secondary molding resin is avoided.

[0056] (4) Writing implements A writing instrument 100 equipped with each of the writing instrument components 10 of the first to third embodiments is shown in a front view (FIG. 17A), a cross-sectional view taken along line XVII-XVII of FIG. 17A (FIG. 17B), a view slightly to the right of FIG. 17A (FIG. 18A), and a cross-sectional view taken along line XVIII-XVIII of FIG. 18A (FIG. 18B). As shown in these figures, this writing instrument 100 accommodates a plurality of refills 200, specifically five refills, more specifically four ballpoint pen refills 210 and one mechanical pencil refill 220, inside a barrel 110 formed by a front barrel 120 and a rear barrel 130. The four ballpoint pen refills 210 each contain ink of a different color. A knock bar 11, which serves as the writing instrument component 10 according to the first embodiment and is composed of a covering portion 20 and an embedded portion 30, is attached to the rear end of each refill 200. The embedded portion 30 of the knock bar 11 attached to the ballpoint pen refill 210 is formed of a synthetic resin of a color corresponding to the color and type of ink that it is fitted to. This makes it possible to identify the color of the ink in the ballpoint pen refill 210 by the color of the display portion 35 (see FIG. 1A) of the knock bar 11. A guide member 140 with five holes is attached inside the barrel 110, and one of the refills 200 is inserted into each hole. A spring 150 is fitted around the outer periphery of the refill 200 with the knock bar 11 attached. The rear end of the spring 150 is supported by the front step 47 (see FIG. 1A) of the knock bar 11 described above, while the front end is supported by the guide member 140.

[0057] Five window holes 131 are formed on the outer periphery of rear barrel 130 along the longitudinal direction. Knock protrusions 43 (see FIG. 1A) of knock bar 11 protrude from these window holes 131. Knock protrusions 43 are movable in the front-to-rear direction along window holes 131. In addition, a rear end hole 132 is formed at the rear end of rear barrel 130, and crown 12 as a writing instrument component 10 according to the second embodiment, which is composed of covering portion 20 and embedded portion 30, is attached here. Furthermore, clip 13 as a writing instrument component 10 according to the third embodiment, which is composed of covering portion 20 and embedded portion 30, is attached near the rear end of rear barrel 130.

[0058] The outer periphery of tip barrel 120 has an area with many fine grooves formed along the longitudinal direction, and this area serves as grip section 122 to prevent slipping. The tip of tip barrel 120 also tapers in diameter, and tip opening 121 is provided at this tip. When knock protrusion 43 of knock bar 11 is pressed in the tip direction, the corresponding refill 200 moves in the tip direction, and its writing tip protrudes from tip opening 121.

[0059] Figure 19 is an enlarged perspective view of the rear end portion of this writing instrument 100. As also shown in Figure 18B, the knock bar 11 located on the right side of the clip 13 is connected to the mechanical pencil refill 220, and this knock bar 11 is the knock bar shown in Figure 6. That is, this knock bar 11 differs from the knock bar 11 connected to other ballpoint pen refills 210 in that the indicator 35 is recessed from the indicator groove 44. This makes it possible to distinguish the mechanical pencil refill 220 from other ballpoint pen refills 210 by the tactile sensation of the knock bar 11.

[0060] (5) Fourth embodiment As shown in the front outer perspective view of Fig. 20A, the front view of Fig. 20B, the rear view of Fig. 20C, the right side view of Fig. 20D, the bottom view of Fig. 20E, the plan view of Fig. 20F, and Fig. 20G, a cross-sectional view taken along the line XX-XX of Fig. 20A, a writing instrument component 10 of the fourth embodiment of the present application is configured as a knock bar 11. The right side view of Fig. 21A, the cross-sectional view of Fig. 21B, and the partially enlarged cross-sectional view of Fig. 21C show the state in which the knock bar 11 is attached to the refill 200.

[0061] The writing instrument part 10 of this embodiment is almost identical to the first embodiment, but differs in the step between the refill attachment part 49, which is the attachment part to the rear end of the refill 200, and the spring outer insertion part 48, and on the opposite side of the abutment surface 53 (Figures 20A to 20E, 20G) with which the rear end surface of the refill 200 abuts, a curved convex surface 54 is protruded toward the axis.

[0062] 21A and 21B, when the knock rod 11 is attached to the refill 200, the refill attachment portion 49 of the knock rod 11 is inserted into the rear end of the refill 200 (FIG. 21C). However, the abutment surface 53 abuts against the rear end of the refill 200, preventing the knock rod 11 from being inserted any further, and therefore the entire convex curved surface 54 is not inserted into the rear end of the refill 200. Due to this convex curved surface 54, the tip side of the refill 200 with the knock rod 11 attached warps outward in the radial direction. This reduces contact and interference between refills 200 when the refills 200 are fed out within the barrel, preventing poor feeding. [Industrial Applicability]

[0063] The present invention can be used when forming writing implement parts such as a knock rod, a crown, or a clip by two-color molding. [Explanation of symbols]

[0064] 10 Writing instrument parts 11 Knock rod 12 Crown 13 clips 20 covering portion 21 receiving portion 22 support surface 30 buried portion 31 flange portion 32 sealing surface 33 Functional section 34 Projection section 35 Display section 40 outer part 41 inner part 42 inner step 43 Knock projection 44 Indication groove 45 Wing 46 Rear step 47 Front step 48 Spring extrapolation 49 Refill attachment portion 50 Locking projection 51 Release projection 52 Recessed portion 53 Contact surface 54 Convex curved surface 60 exposed portion 61 inserted portion 62 flange 70 Fixed part 71 Extension part 72 Display aperture 73 Tamabe 100 Writing instrument 110 Barrel 120 Tip barrel 121 tip opening 122 grip portion 130 rear shaft 131 window hole 132 rear end hole 140 guide member 150 Spring 200 Refills 210 Ballpoint Pen Refills 220 Mechanical Pencil Refills 500 Movable mold 510 Primary runner 515 Primary gate 520 Secondary runner 525 Secondary gate 530 Core pin 540 Core pin outer cylinder 600 Primary molding die 610 Primary cavity 620 Primary support die 630 Primary split mold 700 Secondary forming mold 710 Secondary cavity 720 Secondary support mold 730 Secondary split mold P1 Primary cavity dividing surface P2 Parting surface between the movable mold and secondary molding mold Q Movable mold edge R Primary mold edge

Claims

[Claim 1] The invention described herein.

Images