Refill lead case

Abstract

To provide a refill lead case and a molding method of a refill lead case component, capable of preventing deformation of an inward projection part in mold release, thereby securing stability of a shape, and further solving a problem of generation of scratches on a molded article.SOLUTION: A refill lead case uses, as one refill lead case component 11, a member which is formed by integrally molding right and left leg plates 13 on both sides of a main surface plate 12 so that a cross section orthogonal to the longitudinal direction has a U-shape, and has such inward protrusions 14 on the leg plates as to direct inward with respect to the right and left leg plates. In an inner bottom surface 12a of the main surface plate 12 sandwiched between the right and left leg plates of the refill lead case component 11, a first step part 16 having a level difference by the protrusion molded so as to project with respect to the inner bottom surface is formed along the right and left leg plate sides excluding the center part in the longitudinal direction of the inner bottom surface.SELECTED DRAWING: Figure 12

Description

Technical Field

[0001] This invention relates to a refill case for accommodating a writing core used in a mechanical pencil or the like.

Background Art

[0002] As a refill case for accommodating a writing core used in a mechanical pencil or the like, a case having an elongated outer shape is adopted according to the linear form of the writing core. In this case, in order to take out the writing core from the refill case, a configuration has been proposed in which an elongated inner case is slid relatively along the longitudinal direction within an elongated outer case, which is disclosed in Patent Documents 1 and 2.

[0003] In addition, a proposal has also been made for a refill case that is assembled by press-fitting an elongated lower case and an elongated upper case. According to this refill case, when the upper case is press-fitted into the lower case, a slide lid for opening and closing the outlet of the writing core is fitted between the upper and lower cases, and a device has been provided that enables the refill case to be easily assembled, which is disclosed in Patent Document 3.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, since this type of refill case is formed by combining two or more components as described above, it is necessary to obtain a certain degree of dimensional accuracy for each component. Moreover, in order to improve productivity, injection molding using a resin material as the raw material is often adopted for many of them. Moreover, as described above, each component constituting the refill case adopts a combination of an elongated outer case and an inner case, or a combination of an elongated lower case and an upper case, etc. Therefore, these components often adopt a configuration in which the cross-sectional shape perpendicular to the longitudinal direction thereof is formed in a U-shape, for example, and functional components are integrally formed as inward protrusions on the inner surfaces facing each other in the U-shape so as to face inward.

[0006] When each refill case component formed with the above-described inward protrusion is demolded from the injection mold, the inward protrusion becomes an undercut with respect to the mold. For this reason, a so-called forced ejection method is adopted in which the molded resin product (refill case component) is deformed while being ejected. Therefore, there is a risk that the inward protrusion of the refill case component will sag and deform during demolding. Furthermore, a problem may occur in that the inward protrusion adheres to the mold, making it difficult to demold the resin product.

[0007] The present invention has been made by paying attention to the above-described problems in mold forming of conventional refill case components, and aims to provide a refill case and a method for molding a refill case component that can prevent deformation of the inward protrusion during demolding, ensure shape stability, and enable easy demolding.

Means for Solving the Problems

[0008] The refill case according to the present invention made to solve the above-described problems has left and right footrests integrally provided on both sides of the main panel, so that the cross-section orthogonal to the longitudinal direction is formed in a U-shape, and an inward projecting portion is formed integrally with the footrests so as to face inward. A member formed is used as one refill case part, and on the inner bottom surface of the main panel sandwiched between the left and right footrests of the refill case part, a first stepped portion having a step with respect to the inner bottom surface is formed along the left and right footrest sides excluding the central portion in the longitudinal direction of the inner bottom surface. It is characterized by being.

[0009] In this case, in one preferred form, a configuration is adopted in which a second stepped portion having a step with respect to the inner side surface is continuously formed on the opposing inner side surfaces of the left and right footrests.

[0010] Furthermore, on the inner bottom surface of the main panel sandwiched between the left and right footrests, a third stepped portion having a concavo-convex direction different from that of the first stepped portion is formed at a position deviated from the first stepped portion. In this case, preferably, the first stepped portion is formed by projecting with respect to the inner bottom surface, and the third stepped portion is formed by being recessed with respect to the inner bottom surface.

[0011] On the one hand, the method for molding a replacement core case part according to the present invention made to solve the above-described problems is a method for molding a replacement core case part in which left and right foot plates are integrally provided on both sides of a main panel, and a cross section orthogonal to the longitudinal direction is formed in a U shape, and an inward protruding portion is integrally formed on the foot plates so as to face inward with respect to the left and right foot plates. The method includes a first mold, a second mold, a core pin mounted on the second mold, a slide core that moves along the core pin in a direction inclined with respect to the mold opening direction of the first mold with respect to the second mold, and a protruding pin that moves in the same direction as the mold opening direction of the first mold with respect to the second mold. The method includes a resin injection step of injecting resin into a cavity formed by the first mold, the second mold, the core pin, the slide core, and the protruding pin, a mold opening step of opening the first mold from the second mold, and a mold release step of moving the slide core and the protruding pin simultaneously in the mold opening direction of the first mold, and separating the replacement core case part molded in the cavity from the slide core by the protruding pin.

[0012] In this case, preferably, recesses for forming the inward protruding portions are formed on the opposing inner surfaces of the left and right foot plates, respectively, toward the outside near the tip ends of the pair of slide cores. With the movement of the pair of slide cores in the mold release step, the recesses are relatively moved toward the central portions of the left and right foot plates, and an operation of releasing the inward protruding portions from the pair of slide cores is involved.

Advantages of the Invention

[0013] According to the molding method according to the present invention described above, in the replacement core case part in which a cross section orthogonal to the longitudinal direction is formed in a U shape and an inward protruding portion is formed so as to face inward with respect to the left and right foot plates, when releasing from the slide core, an operation is involved in which the end portion of the slide core relatively moves toward the central portions of the left and right foot plates of the replacement core case part. Thereby, the inward protruding portion integrally molded on the replacement core case part can be released from the slide core without difficulty and received by the protruding pin. Therefore, the refill case component with the inward protrusion integrally formed can prevent the deformation of the inward protrusion during mold release without the forced extraction described above. As a result, a refill case component with ensured shape stability of the inward protrusion can be obtained.

[0014] On the other hand, during resin molding of the refill case component, due to the positional relationship between the core pin and the slide core, a first stepped portion having a step with respect to the inner bottom surface is formed along the left and right leg plate sides excluding the central portion in the longitudinal direction of the inner bottom surface on the inner bottom surface of the main panel of the refill case component. Therefore, when the refill case component is released from the slide core, although the end portion of the slide core moves toward the central portion side of the left and right leg plates, the inner bottom surface of the refill case component can avoid contact with the slide core due to the step. This can contribute to preventing the occurrence of product defects such as scratches on the inner bottom surface caused by the slide core.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

DETAILED DESCRIPTION OF THE INVENTION

[0016] FIGS. 1 to 10 show examples of refill cases using refill case parts obtained by the molding method of the refill case parts according to the present invention. First, based on FIGS. 1 to 10, examples of refill cases will be described, and then the molding method of the refill case parts according to the present invention will be described based on FIGS. 11 to 20.

[0017] FIGS. 1 and 2 show the external configuration of the assembled refill case as a whole, and FIG. 2 shows the state in which the refill L is accommodated in the case. The cover member 1 and the case body 2 that constitute this refill case are molded from a resin material. Also, the inner lid 3 that is attached to the case body 2 and covered by the cover member 1 is similarly molded from a resin material. And the case body 2 and the inner lid 3 are attached to the cover member 1 so as to be slidable along the longitudinal direction, and the refill case is assembled.

[0018] Figures 3 to 10 show the individual component configurations of the case body 2, the inner lid 3, and the cover member 1 described above. Based on each figure showing these individual component configurations, the configurations of each member will be described. Figures 3 and 4 show the case body 2. This case body 2 is formed with a U-shaped cross-section perpendicular to the longitudinal direction by a back plate 2a and left and right foot plates 2b, and a refill accommodation chamber 2c is formed in the inner space surrounded by the U-shape.

[0019] Also, via a bendable thin-walled portion 2d provided near the tip end portion in the longitudinal direction of the back plate 2a, a lid portion 2e is formed on the tip end side, and a case portion 2f is formed on the rear side. And on the lid portion 2e, a closing plate 2g that connects the left and right foot plates 2b and closes the tip end portion of the lid portion 2e is formed, and on the rear portion of the case portion 2f, a rear closing plate 2h that connects the left and right foot plates 2b and closes the rear portion of the case portion 2f is formed.

[0020] On the outer sides of the left and right leg portions 2b of the lid portion 2e, a pair of guide bodies 2j are respectively formed to protrude in a rail shape along the longitudinal direction. As shown in FIG. 4, in the guide body 2j, a parallel region 2j1 parallel to the back plate 2a is formed on the tip end side of the lid portion 2e, and following this parallel region 2j1, an inclined region 2j2 that moves away from the back plate 2a toward the thin-walled portion 2d side is formed. Note that the parallel region 2j1 and the inclined region 2j2 of this guide body 2j come into sliding contact with a sliding body 1g provided on the cover member 1 side along with the sliding operation of feeding out the lid portion 2e of the case body 2 from the tip end portion of the cover member 1, and act to give a pivoting operation that warps the lid portion 2e toward the back side via the thin-walled portion 2d.

[0021] In the left and right foot plates 2b of the above-described case portion 2f, fitting recesses 2k for attaching an inner lid 3 to be described later are formed at substantially the central portion in the longitudinal direction and near the lid body portion 2e. In addition, a pair of slide protrusions 2m are formed along the longitudinal direction of the case body 2 on both outer sides of the left and right foot plates 2b in the case portion 2f. These slide protrusions 2m are engaged with case support portions 1d to be described later provided on the cover member 1, and act so that the case body 2 is slidably supported in the longitudinal direction.

[0022] In addition, rib-shaped click protrusions 2n are formed near the rear portions of the left and right foot plates 2b in the case portion 2f. When the cover member 1 slides with respect to the case body 2, these click protrusions 2n overcome a click body 1f formed on the case body 2 side to generate a click action. Therefore, this click action also occurs when the case body 2 is returned into the cover member 1. Furthermore, a plurality of protrusions 2p for avoiding surface contact with the inserted refill are formed on the inner surface of the back plate 2a of the case portion 2f on the side of the refill accommodation chamber 2c so as to be orthogonal to the longitudinal direction of the case body 2. This serves to prevent the refill L from being adsorbed and sticking due to static electricity on the inner surface of the refill accommodation chamber 2c of the case body 2 formed of a resin material.

[0023] Figs. 5 to 7 show the single-piece configuration of an inner lid 3 attached to the left and right foot plates 2b of the above-described case body 2 and covering the refill accommodation chamber 2c on the front side. This inner lid 3 is formed in a flat shape, and fitting convex portions 3a are formed at the central portion in the longitudinal direction and near the tip portion. These fitting convex portions 3a are fitted into inner lid fitting recesses 2k formed in the case body 2, and are attached so as to cover the refill accommodation chamber 2c of the case body 2 on the front side.

[0024] At this time, a pair of protection plates 3b formed at the tip portion of the inner lid 3 are arranged so as to be located from the thin-walled portion 2d to the lid body portion 2e inside the left and right foot plates 2b of the case body 2. This makes it possible to solve the problem that when the lid portion 2e extended by the sliding operation is returned into the cover member 1, the replacement core L is pinched between the foot plate 2b on the lid portion 2e side warped to the back side and the foot plate 2b on the case portion 2f side.

[0025] Also, at the rear part of the inner lid 3, a pair of spacers 3c formed to protrude from the inner surface of the inner lid 3 act to maintain a certain interval between the inner lid 3 and the back plate 2a of the cover member 1 at the rear part of the inner lid 3. Furthermore, a plurality of protrusions 3d are formed on the inner surface of the inner lid 3 in a direction orthogonal to the longitudinal direction of the inner lid 3. This is to avoid surface contact with the replacement core L in the resin inner lid 3 that covers the replacement core accommodation chamber 2c of the case portion 2f from the front, and to prevent the replacement core L from being adsorbed by static electricity and sticking to the inner lid 3.

[0026] Figs. 8 to 10 show the single-component structure of the cover member 1. This cover member 1 is formed into a U-shaped cross-section orthogonal to the longitudinal direction by the front plate 1a and the left and right outer foot plates 1b. At the rear part of this cover member 1, a rear foot plate 1c connecting the left and right outer foot plates 1b is formed. And the front plate 1a covers the replacement core accommodation chamber 2c of the cover member 1, and positions the left and right foot plates 2b of the case body 2 inside the left and right outer foot plates 1b to slidably support the case body 2 in the longitudinal direction. And it is configured such that the lid portion 2e of the case body 2 is extended from the tip end side of the cover member 1 by the sliding operation.

[0027] Case support portions 1d are formed at two locations in the longitudinal direction along the edges of the left and right outer foot plates 1b so as to face each other inward. These case support portions 1d slidably support the left and right slide protrusions 2m formed on the foot plate 2b of the case body 2, thereby slidably supporting the case body 2 and also functioning to prevent the case body 2 from coming off the cover member 1. And on the inner sides near the rear portions of the left and right outer foot plates 1b, a pair of slide protrusions 1e are formed to face each other. This is for the rib-shaped click protrusions 2n formed on the case body 2 to climb over forward, generating a click action when the case body 2 is opened. Furthermore, on the inner sides of the rear portions of the outer foot plates 1b, a pair of click bodies 1f are formed to face each other. When the case body 2 is slid, the rib-shaped click protrusions 2n formed on the case body 2 climb over backward, generating a click action.

[0028] Inside the outer foot plate 1b at the tip of the cover member 1, sliding bodies 1g project to face each other. When the case body 2 slides and the lid portion 2e protrudes from the tip of the cover member 1, the sliding bodies 1g contact the parallel region 2j1 and the inclined region 2j2 of the guide body 2j formed on the lid portion 2e, functioning to warp the lid portion 2e to the back side.

[0029] Also, near the rear of the above-described sliding bodies 1g at the tip of the cover member 1, stoppers 1h are provided to face each other. When the case body 2 slides and the lid portion 2e is fully opened, the tip of the slide protrusion 2m formed on the foot plate 2b of the case portion 2f abuts against the stoppers 1h, stopping the sliding operation of the case body 2. Also, in the sliding operation of pulling the case body 2 back into the cover member 1, the pair of stoppers 1h contact the return guide portion 2j3 of the guide body 2j, also serving to return the lid portion 2e in the warped state to the state along the longitudinal direction of the case body 2.

[0030] Furthermore, on the surface of the front plate 1a of the cover member 1, as also shown in FIGS. 1 and 2, a circular depression 1k is formed approximately at the center of the cover member 1. When operating the case body 2 by sliding it with respect to the cover member 1, this depression 1k can facilitate the smooth sliding operation of the case body 2 by, for example, placing a thumb on this depression 1k.

[0031] Figures 1 to 10 described above are an example of a replacement core case using the replacement core case parts obtained by the molding method according to this invention. In the following, regarding the molding method of the replacement core case parts shown in Figures 1 to 10 and the resin molding characteristic points of the replacement core case parts obtained thereby, an explanation will be given based on Figures 11 to 20.

[0032] Figure 11 is a schematic diagram showing the molding method of the replacement core case parts in the order of steps (A) to (D). Note that the molding method of the replacement core case parts shown in Figure 11 is suitable for molding replacement core case parts with a U-shaped cross-section perpendicular to the longitudinal direction by integrally providing left and right outer side foot plates 1b on both sides of the front panel 1a, such as the cover member 1 that constitutes a part of the replacement core case already described. In particular, it is suitable for molding replacement core case parts in which inner protruding parts such as the case support part 1d are integrally molded so as to face inward on the left and right outer side foot plates 1b of the cover member 1.

[0033] Therefore, in the following explanation of the molding method of the replacement core case parts, the cover member 1 and the case body 2 described above will be referred to as the replacement core case parts 11, and the front panel 1a of the cover member 1 and the back panel 2a of the case body 2 will be referred to as the main panel 12. Also, the left and right outer side foot plates 1b of the cover member 1 and the left and right foot plates 2b of the case body 2 will be simply referred to as the foot plates 13, and further, the case support part 1d, the slide protrusion 1e, the stopper 1h, etc. molded to face inward on the outer side foot plate 1b of the cover member 1 will be referred to as the inner protruding part 14.

[0034] Figure 11 is a schematic diagram of a resin molding apparatus showing the state of molding the replacement core case parts 11 as the cover member 1 described above. This resin molding apparatus includes, for example, a first mold 21 as a movable mold, a second mold 22 equipped with core pins 23 forming an isosceles trapezoid, and a pair of slide cores 24 that move upward along the core pins in a direction inclined with respect to the mold opening direction of the first mold 21 with respect to the second mold 22, and a push pin 25 that moves upward in the same direction as the mold opening direction of the first mold 21 with respect to the second mold 22. In the example shown in FIG. 11, the push pin 25 is disposed at the center of the core pin 23. However, when molding the case part 11 shown in FIGS. 12 to 20 described later, the push pin 25 will be disposed at a position overlapping the pair of slide cores 24 on the paper surface.

[0035] Note that FIG. 11 shows the state after the first mold 21 is opened from the second mold 22. The resin injection process before this step is performed, as is well known, by injecting resin into the cavity in a state where the first mold 21 is closed with respect to the second mold 22. In this case, the cavity is formed in the space surrounded by the first mold 21, the second mold 22, the core pins 23, the slide cores 24, and the push pin 25 that constitute the resin molding apparatus shown in FIG. 11.

[0036] The state shown in FIG. 11(B) shows the initial state in which the pair of slide cores 24 and the push pin 25 have simultaneously moved in the mold opening direction of the first mold 21. From this initial state, as shown in FIG. 11(C), the pair of slide cores 24 and the push pin 25 further rise while the relative height between the two remains unchanged. As a result, the tip portions of the pair of slide cores 24 move closer to each other toward the central portion side of the case part 11. Thereby, the inner protruding portion 14 of the case part 11 is released from the recesses 24a respectively provided on the outer sides near the tip portions of the slide cores 24, and the case part 11 is received by the tip portion of the push pin 25.

[0037] That is, in the state shown in FIG. 11(C), the inward protruding portion 14 as an undercut portion formed in the case component 11 can be detached from the slide core 24 in the vertical direction. Therefore, as shown in FIG. 11(D), the resin-molded case component 11 can be easily taken out by a robot arm (not shown) or the like.

[0038] According to the above-described method for molding the replacement core case component, when the replacement core case component 11 is demolded, the slide core 24 is accompanied by an operation of moving toward the central portion side of the case component 11. As a result, the inward protruding portion 14 integrally formed with the replacement core case component 11 is easily demolded from the slide core 24 and received by the protruding pin 25. Therefore, the replacement core case component 11 having the inward protruding portion 14 can be demolded without relying on forced ejection, and a replacement core case component 11 that prevents deformation of the inward protruding portion 14 due to forced ejection can be obtained.

[0039] FIGS. 12 to 16 show a first embodiment of the case component 11 molded according to the molding method shown in FIG. 11 for the cover member 1 described above. In this case component 11, on the inner bottom surface 12a of the main panel 12 sandwiched between the left and right leg plates 13, large and small rectangular first step portions 16 having steps formed by protruding molding with respect to the inner bottom surface 12a are formed at six locations along the left and right leg plate 13 sides excluding the central portion in the longitudinal direction of the inner bottom surface 12a.

[0040] Further, on the opposing inner surfaces of the left and right leg plates 13 of this case component 11, second step portions 17 having steps formed by protruding molding with respect to this inner surface are continuously formed in continuation with the above-described first step portions 16. Furthermore, on the inner bottom surface 12a of the main panel 12 sandwiched between the left and right leg plates 13, third step portions 18 having an uneven direction different from that of the first step portions 16, that is, third step portions 18 in a boat-shaped recessed form recessed with respect to the inner bottom surface 12a, are formed at four locations at positions deviated from the first step portions.

[0041] The inner bottom surface 12a of the above-described case part 11 is formed by the top surface of the core pin 23 shown in FIG. 11. Further, the first stepped portion 16 will be formed by the upper end surfaces of the pair of slide cores 24. Furthermore, the second stepped portion 17 is formed by planar recessed portions (not shown) provided on both outer sides of the upper end portion of the core pin 23. And the third stepped portion 18 will be formed by the upper end surface of the protruding pin 25.

[0042] Therefore, according to the first embodiment of the case part 11 shown in FIGS. 12 to 16, since the first stepped portion 16 is formed to protrude with respect to the inner bottom surface 12a, when the case part 11 is released from the slide core, the upper end portion of the slide core 24 slides along the surface of the first stepped portion 16. Therefore, it is possible to prevent the occurrence of product defects such as scratching the inner bottom surface 12a of the case part 11 due to the movement of the slide core 24 accompanying the mold release. Also, according to the first embodiment of the case part 11, the above-described third stepped portion 18 is formed in a recessed shape with respect to the inner bottom surface 12a. Therefore, the case part 11 released from the slide core 24 is received in a stable posture by the protruding pin 25 within the recessed third stepped portion 18.

[0043] FIGS. 17 to 20 show a second embodiment of the case part 11 obtained by molding the case body 2 described above according to the molding method shown in FIG. 11. In addition, in each part of the case part 11 shown in the second embodiment, parts having the same functions as those in the first embodiment shown in FIGS. 12 to 16 are denoted by the same reference numerals, and the description thereof is omitted. In this case part 11, the inward protruding portions 14 are integrally formed with the leg plates 13 along the opening edge portions of the left and right leg plates 13. And on the inner bottom surface 12a of the main panel 12 sandwiched between the left and right leg plates 13, the first stepped portion 16 having a step by protruding molding with respect to the inner bottom surface 12a is formed at four locations along the left and right leg plate 13 sides excluding the central portion in the longitudinal direction of the inner bottom surface 12a.

[0044] In addition, in this second embodiment, on the inner bottom surface 12a of the main panel 12 described above, six circular third stepped portions 18 that are recessed with respect to the inner bottom surface 12a are formed at positions deviated from the first stepped portion 16.

[0045] The inner bottom surface 12a of the case part 11 described above is formed by the top surface of the core pin 23 shown in FIG. 11, and the first stepped portion 16 is formed by the upper end surfaces of a pair of slide cores 24. Furthermore, the third stepped portion 18 will be formed by the upper end surface of the protruding pin 25, and these relationships are the same as those in the first embodiment of the case part 11.

[0046] Therefore, also in the second embodiment of the case part 11 shown in FIGS. 17 to 20, due to the presence of the first stepped portion 16, it is possible to prevent the occurrence of product defects such as scratching the inner bottom surface 12a of the case part 11 due to the movement of the slide core 24 accompanying mold release. Also, due to the presence of the third stepped portion 18, the case part 11 released from the slide core 24 can be received in a stable posture by the tip of the protruding pin 25 located within the third stepped portion 18, and thus the same operational effects as those in the first embodiment can be obtained.

Explanation of Reference Numerals

[0047] 11 Replaceable core case part 12 Main panel 12a Inner bottom surface 13 Foot panel 14 Inner protruding portion 16 First stepped portion 17 Second stepped portion 18 Third stepped portion 21 First mold 22 Second mold 23 Core pin 24 Slide core 24a Recess 25 Protruding pin

Claims

【Claim 1】 The invention described in the specification of this application.

Images