Cap for cosmetic tool

Abstract

To provide a cap for a cosmetic tool that improves seating between members themselves to prevent axial deviation of the members when being assembled.SOLUTION: In a cap for a cosmetic tool, an inward projection is formed on an inner circumferential surface of an outer cap, and a flange part having an outer diameter larger than the inner diameter of the inward projection is formed on an outer circumferential surface of the inner cap. In a state in which a spring is inserted in the outer cap, the inner cap is inserted into the outer cap and pressed therein. As a result, the flange part passes over the inward projection and a rear surface of the flange part is fitted into a front surface of the inward projection, thereby establishing an assembled state in which the inner cap is prevented from coming off by resisting the spring's repulsive force. In the outer cap, prior to fitting of the flange part by passing over the inward projection, a rear end of the inner cap is exposed from an opening side of the outer cap by the spring inserted in the outer cap.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cap for a cosmetic tool that is provided with an inner cap and is easy to assemble. [Background technology]

[0002] Conventionally, cosmetic caps used for ink tank containers containing low-viscosity cosmetic liquids have been disclosed in Patent Documents 1 to 4 to be composed of three parts: an inner cap on the inner tube side, an outer cap on the outer tube side, and a spring that allows the inner cap to slide inside the outer cap in order to prevent an increase in the internal pressure of the ink tank when the cap is opened and closed.

[0003] In this type of cap, the inner cap and the outer cap are prevented from coming off by fitting the flange of the inner cap into a protrusion on the inner wall of the outer cap. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-146366 [Patent Document 2] Japanese Patent Publication No. 2022-178890 [Patent Document 3] Japanese Patent Publication No. 2020-116105 [Patent Document 4] Japanese Utility Model Application Publication No. 6-66514 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in cosmetic caps where the inner cap slides back and forth inside the cap using a spring, assembly defects can occur when the axial directions of the components are not aligned during assembly in the manufacturing process. Also, when a user uses the cap after assembly is complete, the inner cap can be unintentionally pushed too far into the cap, causing it to stop sliding.

[0006] SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a cap for a cosmetic tool that can improve the fit of components together so that the axial direction of the components does not deviate during assembly. [Means for solving the problem]

[0007] The present invention relates to a cosmetic cap comprising a cylindrical outer cap, an inner cap located on the inner surface of the outer cap, and a spring that biases the inner cap toward the opening of the outer cap, wherein an inner protrusion is formed on the inner peripheral surface of the outer cap, and a flange portion having an outer diameter larger than the inner diameter of the inner protrusion is formed on the outer peripheral surface of the inner cap, and when the inner cap is inserted into the outer cap with the spring inserted therein and pressed, the flange portion overcomes the inner protrusion and the rear surface of the flange portion engages with the front surface of the inner protrusion, thereby achieving an assembled state in which the inner cap is prevented from coming off against the elastic force of the spring, and the rear end of the inner cap is exposed from the opening side of the outer cap by the spring inserted into the outer cap before the flange portion overcomes the inner protrusion and engages with the outer cap.

[0008] In the present invention, it is preferable that when the inner cap is inserted into the outer cap, at least half of the total length of the inner cap is inserted into the outer cap.

[0009] In the present invention, it is preferable that at the bottom dead center when the tip of the inner cap pressed during assembly abuts against the inner wall of the outer cap or when the spring is fully compressed, the rear end of the inner cap is positioned closer to the opening end than the inward protrusion inside the outer cap.

[0010] In the present invention, it is preferable that the rear end surface of the inner cap after assembly is located at the same position as or further rearward than the rear end surface of the outer cap.

[0011] The outer diameter of the flange of the inner cap is preferably 101 to 105% of the inner diameter of the inward projection of the outer cap. [Effects of the Invention]

[0012] This reduces the number of defects during assembly of cosmetic caps consisting of an outer cap, spring, and inner cap. It also prevents the application area from drying out due to poor sliding caused by incorrect use by the user. [Brief explanation of the drawings]

[0013] [Figure 1] 1A and 1B are overall views showing a cosmetic applicator according to a first embodiment of the present invention in a capped state, where (a) is an external view and (b) is a longitudinal cross-sectional view. [Figure 2] 1A and 1B are overall views showing a state in which the cap is removed of a cosmetic applicator according to a first embodiment, where (a) is an external view and (b) is a longitudinal cross-sectional view. [Figure 3] 1A and 1B are explanatory diagrams showing the component configuration of the cap according to the first embodiment, in which (a) is a view from the front, (b) is a perspective view from the rear, (c) is a view from the rear, and (d) is a vertical cross-sectional view. [Figure 4] FIG. 2 is an exploded perspective view of the cap according to the first embodiment. [Figure 5] 1A and 1B are part diagrams of an outer cap according to a first embodiment, in which (a) is a perspective view from the front, (b) is a view from the front, (c) is a side view, (d) is a longitudinal cross-sectional view, (e) is a perspective view from the rear, and (f) is a view from the rear. [Figure 6] Component diagrams of the inner cap according to the first embodiment, where (a) is a perspective view from the front, (b) is a view from the front, (c) is a side view, (d) is a longitudinal cross-sectional view, (e) is a perspective view from the rear, and (f) is a view from the rear. [Figure 7] 1A and 1B are component diagrams of a spring according to a first embodiment, in which (a) is a side view and (b) is a perspective view. [Figure 8] 1A to 1D are explanatory views of the assembly procedure of the cap according to the first embodiment, and are longitudinal cross-sectional views of the cap. [Figure 9] 1A to 1J are diagrams illustrating the procedure for assembling the cap according to the first embodiment, with (a) to (e) being longitudinal cross-sectional views and (f) to (j) being external views. [Figure 10] 10A to 10J are diagrams illustrating the procedure for assembling the cap according to the second embodiment, in which (a) to (e) are longitudinal cross-sectional views, and (f) to (j) are external views. [Figure 11] 10A and 10B are explanatory diagrams showing the results of a cap assembly evaluation comparing an example of the present invention with a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described with reference to the drawings. [1. First embodiment] 1.1 Configuration of the first embodiment A cosmetic tool and its cap according to a first embodiment of the present invention will be described.

[0015] 1 and 2 are overall views of the cosmetic applicator with the cap on and with the cap removed.

[0016] As shown in Figures 1 and 2, the cap 24 of the cosmetic applicator (hereinafter also referred to simply as the applicator) according to this embodiment comprises a cylindrical outer cap 24o having an opening (opening) 24b, an inner cap 24i arranged on the inner surface of the outer cap 24o, and a spring 24s that biases the arranged inner cap 24i towards the opening (opening) 24o of the outer cap 24o. As shown in FIGS. 3 and 6, inner cap 24i has an outer peripheral surface (side surface) 24i5 and a flange (brim) 24i1. Flange 24i1 has a front surface 24i2 located on the front barrel 12 side and a back surface 24i3 located on the rear barrel 20 side. Front surface 24i2 has a spring receiving surface 24i22 that receives one end of spring 24s. Back surface 24i3 has a continuous curved surface 24i4 that is connected to outer peripheral surface (side surface) 24i5. The force with which spring 24s presses against spring receiving surface 24i22 is defined as pressing force P (MPa). The connection volume, which is the volume of the region of connection portion 24v between spring receiving surface 24i22 and back surface 24i3 in flange 24i1, is defined as V (mm 3 ) V / P = 27 to 39 is satisfied.

[0017] The cosmetic applicator has a barrel tube in which a cylindrical rear barrel 20 with a closed rear end is fitted onto the rear part of a tapered cylindrical front barrel 12 to form an integrated barrel.

[0018] Applicator part 10 is provided with its tip protruding and exposed in opening 12c at the front end of front barrel 12. The applicator has a removable cap 24 attached to the outer periphery of front barrel 12 to cover applicator part 10 when not in use.

[0019] Rear barrel 20 fits onto the outer periphery of the rear part inside front barrel 12. Flange 12a expands in diameter on the outer periphery of front barrel 12, and rear barrel 20 abuts against the rear side surface of flange 12a. Front barrel 12 and rear barrel 20 form the outer periphery of the barrel tube. Cap 24 abuts against the front side surface of flange 12a.

[0020] The cap 24 is configured by housing an inner cap 24i and a spring 24s inside an outer cap 24o that is fitted with an exterior part 24d. The exterior part 24d is attached to the outer periphery of the cap 24 for the purpose of appearance design and protection against scratches.

[0021] The outer cap 24o has an annular inward protrusion 24o1 formed on its inner peripheral surface in the axial middle, protruding in the inner diameter direction. The inner cap 24i has an annular flange 24i1 formed on the outer peripheral surface of its front end, protruding in the outer diameter direction. As will be described later, when the inner cap 24i is attached to the outer cap 24o, the flange 24i1 rides over the inward protrusion 24o1 to fit (ride-over fit). The spring 24s is a coil spring formed by spirally winding an elastic wire. The spring 24s is roughly hand-drum shaped, with openings at the front and rear, and is disposed inside the outer cap 24o with the front portion of the inner cap 24i inserted into the rear opening. The spring 24s is held between the front side of the flange 24i1 and the inner surface of the top portion 24f of the outer cap 24o.

[0022] A liquid storage section (application liquid tank) 16 that stores a cosmetic product is provided at the rear of the interior of rear barrel 20. A comb-tooth-shaped ink guide section (temporary reservoir) 18 is attached to liquid storage section 16. Comb-tooth-shaped ink guide section 18 is provided in contact with the rear end of applicator section 10. A relay core 14 is provided within comb-tooth-shaped ink guide section 18. Relay core 14 guides the liquid cosmetic product to applicator section 10. The front end of applicator section 10 protrudes and is exposed from opening 12c (see FIG. 2) provided at the tip of front barrel 12. The inner circumferential surface of opening 12c is in contact with the outer periphery of applicator section 10. Within front barrel 12, the tip of relay core 14 is in contact with the inner circumferential surface of the rear end of applicator section 10 to guide the cosmetic product, and comb-tooth-shaped ink guide section 18 guides the application liquid from relay core 14 to applicator section 10 via application liquid guide grooves (slits) 18c, forming an applicator.

[0023] A more specific configuration will now be described.

[0024] 1, the rear end of applicator part 10 is hollow and has flange 10a with an expanded diameter formed on the outside. The tip of applicator part 10 is provided within front barrel 12 so as to protrude from the tip opening of front barrel 12.

[0025] A comb-teeth-shaped ink guide portion 18, which has the function of temporarily storing liquid between multiple leaf elements, is disposed within front barrel 12. Flange 10a is pressed by the tip of comb-teeth-shaped ink guide portion 18 to be fixed within front barrel 12. Relay core 14 within hollow hole 18a of comb-teeth-shaped ink guide portion 18 is structured to guide the liquid cosmetic within liquid storage portion 16 to application portion 10.

[0026] The opening side of the tip of liquid containing section 16 is fixed into the rear part of front barrel 12 by press-fitting or melt-fitting.

[0027] [Comb-shaped ink guide part 18] As shown in Figures 1 and 2, a hollow hole 18a is formed inside the comb-tooth-shaped ink guide portion 18 along the axial direction from the tip to the rear end, and the relay core 14 is attached inside the hollow hole 18a.

[0028] A plurality of ink leaves 18b are arranged at regular intervals around the outer periphery of the comb-shaped ink guide portion 18. The liquid is temporarily stored by the capillary force generated between the ink leaves 18b, and the function of air replacement is exhibited.

[0029] Slits 18c are formed so as to cut the leaves 18b in the vertical direction (axial direction). The comb-shaped ink guide portion 18 is configured so that the liquid cosmetic can flow in and out between the leaves 18b via the slits 18c.

[0030] Furthermore, a rib may be formed inside the hollow hole 18a, and the relay core 14 may be supported by the rib.

[0031] Comb-shaped ink guide portion 18 is attached inside front barrel 12. At the rear end of comb-shaped ink guide portion 18, hollow hole 18a and slit 18c face the opening at the front of liquid containing portion 16.

[0032] The rear end face (rear end) of the relay core 14 mounted in the hollow hole 18a of the comb-tooth ink guide section 18 is exposed to the front opening of the liquid storage section 16, and the relay core 14 guides the liquid (liquid cosmetic) in the liquid storage section 16 forward (towards the application section 10).

[0033] The tip of the comb-tooth-shaped ink guide portion 18 is cup-shaped, and the cup tip fits into and is positioned in a stepped portion 12d formed inside the front barrel 12. The cup-shaped tip of the comb-tooth-shaped ink guide portion 18 presses against the rear end of the applicator portion 10 (the rear end surface of the flange 10a). The tip of the relay core 14 inside the comb-tooth-shaped ink guide portion 18 is inserted into the rear end space of the applicator portion 10. The rear end of the comb-tooth-shaped ink guide portion 18 is exposed toward the liquid storage portion 16, and when the internal pressure of the liquid storage portion 16 increases due to changes in air pressure or temperature, the application liquid in the liquid storage portion 16 passes through the slits 18c and is reserved between the leaves 18b of the comb-tooth-shaped ink guide portion 18. When the internal pressure of the liquid storage portion 16 decreases due to consumption of the application liquid, the application liquid reserved in the comb-tooth-shaped ink guide portion 18 returns to the liquid storage portion 16 via the slits 18c. Front barrel 12 is formed with ventilation holes 12b that allow ventilation between the inside and outside of comb-tooth shaped ink guide portion 18 for gas-liquid replacement.

[0034] Outside air circulates through vent hole 12b into the interior of front barrel 12, and then through sheets 18b and slits 18c on the outer periphery of comb-tooth-shaped ink guide portion 18 housed within front barrel 12. Therefore, even if there is a fluctuation in the internal pressure of liquid containing portion 16, this is alleviated by the ventilation within front barrel 12, preventing the coating liquid from spraying out from coating portion 10 and the like, running out of coating liquid, and the like.

[0035] [Liquid storage section 16] As shown in Figures 1 and 2, the liquid storage section 16 is a generally cylindrical container (tank) with an opening at the front and a closed rear end, and stores the application liquid inside. The rear of the comb-tooth ink guide section 18 attached to the front barrel 12 is adjacent to the front of the liquid storage section 16, and the application liquid flows through the opening to the relay core 14 and the slit 18c. An agitator 16a is stored within the liquid storage section 16 to agitate the application liquid within the liquid storage section 16. The agitator 16a is made of metal, resin, or the like, and may be, for example, rod-shaped or spherical, but may also be of other shapes.

[0036] The coating liquid contained in the liquid storage section 16 preferably contains at least sodium polyaspartate, citric acid, one or two types of iron oxide particles selected from red iron oxide, black iron oxide, and yellow iron oxide, a film-forming resin, and water. The viscosity of the cosmetic measured at a shear rate of 192 s-1 and a temperature of 25°C is 15 mPa·s or less. The iron oxide particles in the aqueous liquid cosmetic have an average particle size of 30 nm to 100 nm as measured and calculated by dynamic light scattering. The iron oxide particles in the aqueous liquid cosmetic are preferably dispersed in water by the sodium polyaspartate. This aqueous liquid cosmetic exhibits excellent dispersibility and stability over time, even when iron oxide particles are used as a colorant in the liquid cosmetic, and exhibits no sedimentation or color separation. The "average particle size" refers to a value measured and calculated by dynamic light scattering (using a particle size analyzer, FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.).

[0037] Specifically, sodium polyaspartate is a type of anionic polymer dispersant that improves the dispersibility of iron oxide particles, which serve as a colorant. The content of the anionic polymer dispersant is preferably 0.1 to 10.0% by mass relative to the total amount of the cosmetic composition. If the content is less than 0.1% by mass, the dispersion stability of iron oxide particles, such as red iron oxide, which serve as a colorant, will be insufficient. On the other hand, if the content exceeds 10.0% by mass, the viscosity will be too high, and no improvement in dispersion stability will be observed, making it uneconomical.

[0038] The content of iron oxide particles is preferably 1.0 to 20% by mass relative to the total amount of the cosmetic composition. If the content of iron oxide particles is less than 1.0% by mass, the color development and hiding power will be insufficient, while if it exceeds 20% by mass, the viscosity will increase, which is undesirable.

[0039] Citric acid is a type of aliphatic hydroxy acid with a molecular weight of 300 or less, and is preferably contained in an amount of 0.01 to 2.0% by mass relative to the total amount of the cosmetic composition. If it is contained in an amount less than 0.01% by mass, the above effects will be insufficient, while if it is contained in an amount exceeding 2.0% by mass, the pH will decrease, which is undesirable.

[0040] Examples of film-forming resins include emulsion resins of copolymers made from one or more monomers selected from acrylic acid, methacrylic acid, or alkyl esters or derivatives thereof, styrene, and vinyl acetate. From the viewpoints of water resistance and application performance, the content of the film-forming resin (emulsion resin) is preferably 2 to 15 mass % in terms of solid content (resin content) relative to the total amount of the cosmetic composition.

[0041] The content of water is the balance after the above-mentioned components are contained. The viscosity was measured using an ELD-type viscometer manufactured by Toki Sangyo Co., Ltd., with a standard rotor of 50 rpm (shear rate: 192 [s-1]) at a temperature of 25°C (including the Examples described below).

[0042] [Front axis 12] As shown in Figures 1 and 2, front barrel 12 is a resin product with a generally tubular, hollow structure. More specifically, front barrel 12 is shaped like a pipe with a tapered front section and a rear section of roughly the same diameter. Front barrel 12 is made of a liquid-tight material, such as polyethylene, polypropylene, ABS (Acrylonitrile butadiene styrene), or any of a variety of other synthetic resin materials.

[0043] Front barrel 12 has a front portion into which cap 24 is removably fitted, and a rear portion into which rear barrel 20 is fitted. Flange 12a is formed to protrude in the outer diameter direction on the outer peripheral surface at the boundary between the front and rear portions. When cap 24 is fitted onto front barrel 12, the rear end of cap 24 abuts against flange 12a, thereby positioning it.

[0044] The inside of front barrel 12 is angled in a stepped manner to reduce its diameter, and as shown in FIG. 2, step 12d is formed on the inner surface at the location where the rear of application part 10 and the tip of comb-teeth-shaped ink guide part 18 are located. Air vent 12b is opened (opened) slightly along the axial direction in a rear area adjacent to step 12d. Air vent 12b is formed in multiple locations in the circumferential direction. The area inside front barrel 12 adjacent to air vent 12b connects to step 12d, which has a reduced diameter. The tip of comb-teeth-shaped ink guide part 18 is fitted into and fixed to this step 12d.

[0045] Front barrel 12 reduces in diameter in a step at step 12d. From step 12d forward, the inner surface gradually tapers in diameter until it reaches opening 12c. Applicator part 10 is attached to the interior from step 12d to opening 12c. In front barrel 12, the inner diameter of opening 12c at the front is the smallest throughout the front and rear portions.

[0046] The rear portion of front barrel 12 is formed in a roughly cylindrical shape, with flange 12a formed to expand outward on the outer periphery of that rear portion. The portion of front barrel 12 rearward of flange 12a is inserted into and fixed to the tip portion of rear barrel 20 (see FIG. 1). When front barrel 12 is attached to rear barrel 20, flange 12a abuts against the tip portion of rear barrel 20, preventing front barrel 12 from slipping inside rear barrel 20.

[0047] Concave and convex portions are formed in multiple locations on the outer periphery of the rear part of flange 12a of front barrel 12 to prevent and secure rear barrel 20 when it is fitted. Concave and concave portions are also formed in locations on the inner periphery of rear barrel 20 that correspond to these multiple locations, and they fit together to maintain a liquid-tight seal and prevent it from coming loose.

[0048] [Rear axis 20] In rear barrel 20, exterior portion 20o covers interior portion 20i, and interior portion 20i covers liquid storage portion 16. Liquid storage portion 16, which is a cosmetic tank, is fitted into the rear portion of front barrel 12 and is covered within rear barrel 20.

[0049] The rear barrel 20 has a dual structure in which the exterior portion 20o is attached to the outside of the interior portion 20i. The interior portion 20i and the exterior portion 20o are made of resin or metal. For example, the interior portion 20i may be made of resin and the exterior portion 20o may be made of metal. More specifically, it is preferable that the interior portion 20i be made of various resin materials such as polyethylene, polypropylene, ABS, etc., and the exterior portion 20o be made of a material with a glossy surface, such as metal or various alloys such as aluminum or duralumin, or ceramic. The interior portion 20i covers the liquid container 16. As a result, the liquid container 16, which serves as a cosmetic tank, is covered within the rear barrel 20 while fitted into the rear portion of the front barrel 12.

[0050] When different materials are used for the interior portion 20i and the exterior portion 20o, there is usually a difference in the thermal expansion coefficients. Therefore, when the interior portion 20i and the exterior portion 20o thermally expand, they may interfere with each other and deform. To avoid this deformation, a gap (clearance) 20b is provided between the interior portion 20i and the exterior portion 20o at the rear end of the rear axle 20. This makes it possible to prevent the interior portion 20i and the exterior portion 20o from deforming due to thermal expansion. Furthermore, providing the gap 20b can improve dimensional variations during manufacturing and impact resistance when dropped.

[0051] [Application part 10] The applicator part of the applicator unit 10 has a brush-tip shape made of a fiber bundle of many fibers, an open-cell foam, or the like. When a brush made of a fiber bundle is used as the applicator part, it may be a fine brush with an outer diameter of 2 mm or less. The fibers used in the fiber bundle may be natural or artificial. For example, synthetic resin fibers made of polyamide fiber, nylon fiber, or polyester fiber such as PBT (polybutylene terephthalate) can be used in the fiber bundle.

[0052] 1 and 2, the applicator part 10 is made of a bundle of resin fibers. The applicator part 10 has a tapered shape that becomes thinner toward the tip. The rear end of the applicator part 10 is formed by heat welding into a flange shape (flange 10a) that protrudes toward the outer periphery. This heat welding secures the fiber bundle that makes up the applicator part 10 so that it does not come apart.

[0053] At the rear end of the applicator part 10, the spaces between the fibers in the peripheral flange 10a are tightly packed, making it difficult for the application liquid to seep in. However, at the center of the applicator part 10, which includes the axial center of the barrel, there are gaps between the fiber bundles, making it easier for the application liquid to seep in. The relay core 14 abuts against this center of the applicator part 10, and as a result, the relay core 14 guides the liquid in the liquid storage part 16.

[0054] [Relay core 14] 2, the relay core 14 has a recess 14a on the peripheral surface of its tip. When the relay core 14 is fitted into the comb-teeth-shaped ink guide portion 18, the inner peripheral protrusion 18d of the comb-teeth-shaped ink guide portion 18 fits into the recess 14a. This fitting prevents the relay core 14 from coming loose.

[0055] The relay core 14 has a structure that can exert capillary force to guide the liquid. The relay core 14 is made of a fiber bundle or a molded core made of a resin material or the like. The relay core 14 is preferably made of a material that is substantially free of formaldehyde, such as an olefin-based elastomer. This is because materials that contain formaldehyde may leach formalin from the relay core 14 into the cosmetic liquid, making them unsuitable for use as a cosmetic tool. Furthermore, the relay core 14 is more preferably made of a material that does not contain acetal resins such as polyacetal, phenolic resins, or urea resins and melamine resins used in adhesives.

[0056] [Cosmetics] The liquid storage section 16 contains a liquid cosmetic solution. The liquid cosmetic preferably contains, for example, at least carbon black, water, 0.5 to 5% by mass of a dispersant made of a film-forming resin, 2 to 15% by mass (solids content) of a film-forming agent, and 0.5% by mass or less of a surfactant, and may further contain other materials. The liquid cosmetic preferably has a viscosity in the range of 2 to 8 mPa·s at a temperature of 25°C and a shear rate of 3.83 S-1, as measured by an ELD-type viscometer.

[0057] [Cap 24] [Exterior part 24d and outer cap 24o] 1 and 2, the cap 24 has a cylindrical shape with a closed front end and an open rear end. The exterior part 24d visible from the outside of the cap 24 has a cylindrical shape with a closed front end and an open rear end. The outer cap 24o is housed inside the cylinder of the exterior part 24d.

[0058] The exterior part 24d and the outer cap 24o are made of resin, metal, ceramic, or the like. The exterior part 24d and the outer cap 24o may be made of the same material or different materials. For example, the outer cap 24o may be made of resin, and the exterior part 24d may be made of metal. More specifically, the outer cap 24o may be made of various resin materials such as polyethylene, polypropylene, ABS, or the like, and the exterior part 24d may be made of metals such as various alloys such as aluminum and duralumin, or ceramic.

[0059] Typically, different materials have different thermal expansion coefficients, so when different materials are used, there is a risk that the exterior part 24d and the outer cap 24o may interfere with each other due to thermal expansion. To avoid this, as shown in FIG. 2(b), a gap 24a is provided between the exterior part 24d and the outer cap 24o. By providing the gap 24a, it is possible to prevent the top part 24f, which has been deformed due to thermal expansion, from interfering with the exterior part 24d. Furthermore, by providing the gap 24a, it is possible to absorb dimensional variations during manufacturing and improve impact resistance when dropped.

[0060] [Outer cap 24o and inner cap 24i] 3 shows the cap 24 without the exterior part 24d, FIG. 4 shows the cap 24 in FIG. 3 disassembled, FIG. 5 shows the outer cap 24o alone, and FIG. 6 shows the inner cap 24i alone.

[0061] As shown in FIGS. 3 and 4, the outer cap 24o accommodates the inner cap 24i and the spring 24s.

[0062] 5, the outer cap 24o has a cylindrical shape with a top portion 24f that is closed at the front end and an opening 24b at the rear end. The outer cap 24o also has an inward protrusion 24o1. The inward protrusion 24o1 is annularly provided on the inner circumferential surface of the outer cap 24o so as to be perpendicular to the longitudinal direction of the outer cap 24o.

[0063] The inner diameter of the outer cap 24o preferably has a tapered shape, narrowing at the opening and widening at the top 24f. The taper angle of this tapered shape is preferably about 0.2 degrees, for example. This allows for a wider range of molding conditions for the outer cap 24o. It also makes it less likely for the inward protrusions 24o1 to be torn off when they are cut.

[0064] As shown in FIG. 6, the inner cap 24i is made of synthetic resin, such as polypropylene, and has a generally tubular, hollow structure. The inner cap 24i is shaped like a pipe, tapering toward the front and maintaining a generally constant diameter toward the rear. The inner cap 24i also has a flange 24i1. When the cap 24 is assembled, the outer circumferential surface of the inner cap 24i from the flange 24i1 toward the front is configured to fit inside the spring 24s. The flange 24i1 has a flange shape that expands in diameter outward from an outer circumferential surface 24i5 slightly forward of the longitudinal center of the inner cap 24i.

[0065] The outer diameter of the flange 24i1 is smaller than the inner diameter of the outer cap 24o. To ensure clearance, for example, the outer diameter of the flange 24i1 is preferably smaller than the inner diameter of the outer cap 24o by 0.1 to 0.3 (mm). The outer diameter of the rear end of the inner cap 24i is smaller than the inner diameter of the outer cap 24o. Furthermore, the longitudinal length of the inner cap 24i is shorter than the longitudinal length of the interior of the outer cap 24o. Therefore, the outer cap 24o can accommodate the entire inner cap 24i, including the flange 24i1 and the rear end.

[0066] The flange 24i1 has a front surface 24i2 facing forward and a back surface 24i3 facing rearward. A step 24i7 is further formed on the forward side of the front surface 24i2. The flange 24i1 also has a curved surface 24i4 as an R-shape connecting the back surface 24i3 and the outer peripheral surface 24i5. The provision of the curved surface 24i4 improves the crack resistance of the flange 24i1 and prevents cracks when the flange 24i1 is press-fitted into the inward protrusion 24o1.

[0067] Furthermore, the pressing force of the spring 24s pressing the spring receiving surface 24i22 is P (MPa), and the volume of the connecting portion 24v in the area between the spring receiving surface 24i22 and the back surface 24i3 of the flange portion 24i1 is V (mm 3 ), V / P=27 to 39 is satisfied. FIGS. 3 and 6 show an outline of the receiving surface 24i22 and the connecting portion volume V of the connecting portion 24v.

[0068] When assembling the cap 24, the inner cap 24i is inserted into the outer cap 24o through the opening 24b with the spring 24s inserted (housed) in the outer cap 24o. During insertion, the flange 24i1 of the inner cap 24i is press-fitted onto the inward protrusion 24o1 of the outer cap 24o, and the flange 24i1 rides over the inward protrusion 24o1 to fit (over-fit). Due to this over-fitting, the flange 24i1 is held forward of the inward protrusion 24o1, as shown in FIG. 3(c).

[0069] Since assembly is performed using a jump-over fit, the flange 24i1 must be able to climb over the inner protrusion 24o1 when attaching the inner cap 24i to the outer cap 24o. At the same time, a sufficient fitting force is required to prevent the inner cap 24i from slipping off the outer cap 24o. To ensure sufficient fitting force, the outer diameter of the flange 24i1 is configured to be somewhat larger than the inner diameter of the inner protrusion 24o1. This configuration provides an overlap between the outer diameter of the flange 24i1 and the inner diameter of the inner protrusion 24o1. This overlap is preferably 0.05 to 0.5 mm, for example. In this case, the flange 24i1 and the inner protrusion 24o1 have a fitting force of 10 to 80 N after the jump-over fit.

[0070] 1(b), when the cap 24 is closed, the inner protrusion 24o1 abuts and slides against the outer peripheral surface of the inner cap 24i while maintaining an airtight seal. This prevents the inner cap 24i from rattling and the application part 10 from drying out. In this way, the inner protrusion 24o1 serves both to prevent the inner cap 24i from falling off the outer cap 24o and to abut and slide against the outer peripheral surface of the inner cap 24i while maintaining an airtight seal when the cap 24 is closed.

[0071] 1, when the applicator is not in use, cap 24 is attached so as to cover the area from applicator part 10 to front barrel 12. At this time, inner cap 24i is in airtight contact with the sloped outer surface of front barrel 12, behind air vent 12b.

[0072] [Spring 24s] The spring 24s is a biasing member, and is a barrel-shaped coil spring made of an elastic material such as metal or resin. As shown in Fig. 7, the spring 24s has a front end 24s1, a rear end 24s3, and a middle portion 24s2. Comparing the inner and outer diameters, the inner and outer diameters of the front end 24s1 and the rear end 24s3 are smaller than the inner and outer diameters of the middle portion 24s2. Meanwhile, comparing the winding density, the winding density of the front end 24s1 and the rear end 24s3 is higher than the winding density of the middle portion 24s2.

[0073] When cap 24 is closed, front barrel 12 presses inner cap 24i forward. Accordingly, front surface 24i2 of flange 24i1 presses spring 24s forward, compressing spring 24s between top portion 24f and front surface 24i2.

[0074] At this time, the front end portion 24s1 and the rear end portion 24s3 have a smaller diameter and higher density than the middle portion 24s2, and therefore the degree of elastic deformation is smaller. Therefore, the inner cap 24i can press the spring 24s while stably maintaining contact between the front end portion 24s1 and the apex 24f and between the rear end portion 24s3 and the front surface 24i2. On the other hand, the middle portion 24s2 has a relatively larger diameter and lower density, and therefore the degree of elastic deformation is greater. Therefore, sufficient elastic force can be ensured by the elastic deformation of the middle portion 24s2.

[0075] When the cap 24 is assembled, the spring 24s is entirely housed in the outer cap 24o. Therefore, the outer diameter of the spring 24s, particularly the outer diameter of the middle portion 24s2, is smaller than the inner diameter of the outer cap 24o. For example, it is preferable that there be a clearance of 1.0 to 1.1 mm in diameter between the outer diameter of the middle portion 24s2 and the inner diameter of the outer cap 24o.

[0076] As shown in Fig. 3, inside outer cap 24o, spring 24s biases inner cap 24i rearward. Outer cap 24o is fitted onto front barrel 12 and abuts against flange 12a (see Fig. 1).

[0077] As shown in Fig. 5, fixing protrusion 24g is formed on the rear end side of the inner circumferential surface of outer cap 24o. Protrusion 24g fits into recess 12e on the outer circumferential surface of front barrel 12, preventing cap 24 from coming off front barrel 12 (see Fig. 1). Rear end 24e of outer cap 24o abuts against flange 12a, closing cap 24.

[0078] [1.2 Actions and Effects of the First Embodiment] According to the cosmetic applicator of the first embodiment, a sufficient engagement margin is provided between the flange portion 24i1 and the inward projection 24o1. This increases the engagement force between the flange portion 24i1 and the inward projection 24o1. As a result, the inner cap is less likely to come off the assembled cap.

[0079] 6, a curved surface 24i4 is provided on the back surface 24i3 of the flange portion 24i1, and a curvature R is provided at the base of the flange portion 24i1. This makes it possible to make the flange portion 24i1 less likely to crack when the inner cap 24i is press-fitted into the outer cap 24o during cap assembly.

[0080] Furthermore, the pressing force of the spring 24s pressing the spring receiving surface 24i22 is P (MPa), and the connecting portion volume, which is the volume of the connecting portion 24v in the region between the spring receiving surface 24i22 and the back surface 24i3 of the flange portion 24i1, is V (mm 3 ) V / P = 27 to 39 is satisfied.

[0081] [1.3 Assembly of the Cap of the First Embodiment] 8 and 9 show the procedure for assembling the applicator cap of the embodiment. In Fig. 9, cross-sectional views (a) to (e) correspond to external views (f) to (j).

[0082] First, as shown in Figures 8(a), 9(a), (b), (f), and (g), when inserting the spring 24s into the outer cap 24o, the end face of the rear end 24s3 of the spring 24s is positioned rearward of the outer cap 24o. As shown in Figure 9(a), the distance L1 from the rear end 24s3 of the spring 24s to the opening 24b is set shorter than the distance Lo from the inward protrusion 24o1 to the opening 24b.

[0083] Next, as shown in Figures 8(b), 9(c), and 9(h), the inner cap 24i is inserted through the rear opening of the outer cap 24o and temporarily placed. At this time, the inner cap 24i is positioned so that its end face is exposed through the opening 24b at the rear end of the outer cap 24o. As shown in Figure 8(b), the distance L2 by which the inner cap 24i is inserted from the opening 24b is set to be shorter than the total length Li of the inner cap 24i.

[0084] Next, as shown in FIGS. 8(c), 9(d), and 9(i), a jig or the like is used to press the inner cap 24i forward from the rear opening of the outer cap 24o, causing the spring 24s to elastically compress and the flange 24i1 to overcome the inner protrusion 24o1. At this time, the inner cap 24i can be pressed until its leading end abuts or approaches the inner surface of the top 24f of the outer cap 24o. As shown in FIG. 8(c), the rear end of the inner cap 24i is positioned a distance L3 rearward of the inner protrusion 24o. Furthermore, by setting the engagement between the flange 24i1 and the inner protrusion 24o1 to 0.1 to 0.3 mm in accordance with the embodiment, the pull-out force can be adjusted to a range of 10 to 70 N, which is a fitting force that will not cause damage to components.

[0085] 8(d), 9(e), and 9(j), by releasing the forward pressure on the inner cap 24i, the elastic force of the spring 24s presses the inner cap 24i rearward and moves, and the flange 24i1 catches and engages with the inner protrusion 24o1, preventing it from moving further rearward and from coming off. In the cap 24 of the first embodiment, when the flange 24i1 catches and engages with the inner protrusion 24o1, the rear end of the inner cap 24i is at the same position Ls as the rear end of the outer cap 24o.

[0086] [2. Second Embodiment] Fig. 10 is an explanatory view of assembly of a cap according to the second embodiment. In the cap 24 of the second embodiment, the length of the rear end of the inner cap 24i is longer than that of the first embodiment, and as shown in Fig. 10(e), when the inner cap 24i is pressed rearward by the elastic force of the spring 24s and the flange 24i1 is caught and locked on the inward protrusion 24o1, the rear end of the inner cap 24i is positioned so as to protrude rearward beyond the rear end of the outer cap 24o (protruding by a length A). Other than that, the second embodiment is similar to the first embodiment, and therefore the same parts are denoted by the same reference numerals.

[0087] [3. Features of assembly of the first and second embodiments] The features of assembling the cap according to this embodiment are as follows: When assembling, the rear opening of the outer cap 24o faces upward, and the spring 24s and inner cap 24i are inserted downward into the outer cap 24o with their axes aligned from above.

[0088] [1] When assembling the cap, the spring 24s is positioned so that it does not protrude from the outer cap 24o when inserted into the outer cap 24o (see Figures 8(a), 9(b), and 10(b)).

[0089] [2] When the inner cap 24i is inserted (see Figures 8(b), 9(c), and 10(c)), more than half of the total length of the inner cap 24i is positioned inside the outer cap 24o. This is to prevent the inner cap 24i from rolling off. This is also preferable because the spring 24s abuts against the front surface of the flange 24i1 formed on the outer peripheral surface of the middle of the inner cap 24i, thereby stabilizing the position.

[0090] [3] The bottom dead point during press-fitting occurs when the bottom surface of the outer cap 24o and the top surface (top 24f) of the inner cap 24i collide (see Figures 8(c), 9(d), and 10(d)). At this time, the bottom dead point is set so that the opening end of the inner cap 24i does not sink below the undercut (inward protrusion 24o1) for fitting the flange 24i1 of the inner cap 24i inside the outer cap 24o.

[0091] This setting prevents the inner cap 24i from slipping in when pressed in.

[0092] At the bottom dead center where the inner cap 24i pressed during assembly does not move forward any further inside the outer cap 24o, the rear end of the inner cap 24i is located closer to the opening end than the inward projection 24o1 inside the outer cap 24o.

[0093] [4] After the press-fitting is complete, the rear end face of the inner cap 24i is aligned with the rear end face of the outer cap 24o (first embodiment: see Figures 8(d) and 9(e))), or the rear end face of the inner cap 24i protrudes beyond the rear end face of the outer cap 24o (second embodiment: see Figure 10(e)). The flange 24i1 and the undercut (inward protrusion 24o1) are positioned in such a manner that the rear end face of the inner cap 24i is aligned with the rear end face of the outer cap 24o (second embodiment: see Figure 10(e)).

[0094] This positional relationship makes it possible to prevent brush fibers from getting between the outer cap 24o and the inner cap 24i when closing the cap.

[0095] Furthermore, by making the spring constant of the spring 24s higher than the weight of the inner cap 24i, the position of the inner cap 24i can be prevented from changing due to bending when the inner cap 24i is temporarily placed, and the presence or absence of the spring 24s can be reliably determined.

[0096] An example of product dimensions of the cap according to the first embodiment (L1 to L4: see FIG. 8) is as follows: [1] Distance L1 between the cap end and the spring end: approx. 12 mm [2] Distance L2 between the top surface of the inner cap and the end surface of the cap: approx. 20 mm [3] Distance L3 between the inner cap end face and the cap protrusion: approx. 4 mm [4] Distance L4 between the inner cap end face and the cap end face: approx. 0.1 mm

[0097] Next, FIG. 11 shows the results of evaluation of the ease of assembly of the cap according to the present invention and the comparative example.

[0098] In Examples 1 to 5 shown in Figure 11, the ratio of the outer diameter of the flange portion of the inner cap to the inner diameter of the inward projection of the outer cap is in the range of 101 to 105%. The interference is 0.1 to 0.3 mm. On the other hand, in Comparative Examples 1 to 4, the inner diameter of the flange portion is outside the range of 101 to 105% of the inner diameter of the inward projection. The interference is less than 0.1 mm or more than 0.3 mm. The numerical unit is (mm), and the average of n=50 is shown.

[0099] The assembly evaluation results showed that "A" meant that assembly was possible without any problems, "B" meant that the inner cap did not stop halfway or there were problems with the spring popping out, and "C" meant that the press-fit force was too high and insertion was difficult.

[0100] Therefore, Examples 1 to 5 were good and could be assembled without any problems, but Comparative Examples 1 to 4 were rated "B" or "C," which indicates that the quality of the assembly was inadequate for a cap with an inner cap.

[0101] As described above, according to the application cap of the embodiment, by clarifying the positional relationship between components in each assembly process, assembly can be facilitated and defects can be prevented.

[0102] In addition, in order to prevent the end (rear end) of the inner cap 24i from getting caught on the protrusion inside the cap 24 (inner protrusion 24o1), which can cause poor sliding due to excessive pushing of the inner cap 24i, the bottom dead center is set so that the end of the inner cap 24i does not get caught on the protrusion (inner protrusion 24o1) of the cap 24 when the inner cap 24i reaches the bottom dead center.

[0103] In addition, by aligning or protruding the end faces of the outer cap 24o and inner cap 24i of the assembled product, it is possible to prevent the brush fibers (application part 10) from getting caught between the outer cap 24o and inner cap 24i when closing the cap.

[0104] The above embodiment is one embodiment of the present invention, and can be freely modified and implemented within the scope of the present invention. [Industrial Applicability]

[0105] The cap of the present invention can be used for a cosmetic applicator. [Explanation of symbols]

[0106] 10 Application section 12 front axis 14 Relay core 16 Liquid storage section 18 Comb-shaped ink guide part 20 rear axle 24 Cap 24b opening 24d Exterior part 24e Rear end 24f top 24g convex part 24i Inner Cap 24i1 Tsubabe 24i2 front 24i3 back 24i4 curved surface 24i5 Outer surface 24i7 Stepped section 24o outer cap 24o1 Medial process 24s Spring 24s1 front end 24s2 Midsection 24s3 rear end

Claims

1. A cosmetic cap includes a cylindrical outer cap, an inner cap located on the inner surface of the outer cap, and a spring that biases the inner cap toward the opening of the outer cap. An inner protrusion is formed on the inner peripheral surface of the outer cap, and a flange portion having an outer diameter larger than the inner diameter of the inner protrusion is formed on the outer peripheral surface of the inner cap, With the spring inserted inside the outer cap, the inner cap is inserted into the outer cap and pressed, causing the flange to climb over the inner protrusion and the rear surface of the flange to fit into the front surface of the inner protrusion, preventing the inner cap from coming off against the resilient force of the spring. This cosmetic cap is characterized in that the rear end of the inner cap is exposed from the opening side of the outer cap by a spring inserted into the outer cap before the flange part of the outer cap gets over the inner protrusion and fits onto the outer cap.

2. 2. The cosmetic cap according to claim 1, wherein the inner cap is positioned so that at least half of the total length of the inner cap is inserted into the outer cap when the inner cap is inserted into the outer cap.

3. A cosmetic cap according to claim 2, characterized in that at the bottom dead center when the tip of the inner cap pressed during assembly abuts against the inner wall of the outer cap or when the spring is fully compressed, the rear end of the inner cap is located closer to the opening end than the inward protrusion in the outer cap, and the rear end face of the inner cap after assembly is located at the same position as or further rearward than the rear end face of the outer cap.

Images