Nail clippers

Abstract

To provide a pair of nail clippers that has high durability as well as smoothly and neatly clipping nails.SOLUTION: A pair of nail clippers includes: a first blade body (10) that has a first blade attachment part (13) in a first tip part (12) situated at a tip portion; a second blade body (20) that has a second blade attachment part (23) in a second tip part (22) situated at the tip portion; and an operation member (30) that operates so that the first blade attachment part and the second blade attachment part move closer to and apart from each other. The first tip part (12) is provided with a blade face (15) exposed outer side and a blade back (16) situated on the back side of the blade face. The blade back (16) is curved such that an angle relative to the vertical direction becomes larger as it leaves from the blade edge at the tip of the first blade attachment part and, at the blade edge of the first blade attachment part, an angle formed by the blade face and the blade back is 20° or more and 35° or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One aspect of the present invention relates to a nail clipper. [Background technology]

[0002] Conventionally, there have been nail clippers as described in Patent Document 1 or 2. In the nail clipper described in Patent Document 1, the support part of the upper operating lever and the support part of the lower operating lever are inserted between the upper and lower blade bodies through their support holes with the upper and lower blade edges facing each other, and are supported by the pivot joint between the upper and lower blade bodies so as to be pivotable relative to each other. The force point part of the upper operating lever is located between the upper and lower blade edges and the pivot joint, and engages with the outside of the support hole in the lower blade body. The force point part of the lower operating lever is located between the upper and lower blade edges and the pivot joint, and engages with the outside of the support hole in the upper blade body.

[0003] The nail clipper described in Patent Document 2 includes a support. A cutting member is disposed within the support. A cutting blade is formed at the front end of the cutting member, and the cutting blade side has elasticity in the direction away from each other. A support shaft is inserted through the support body and the front end of the cutting member. A pressing lever is rotatably supported at the upper end of the support shaft. The cutting member is supported on the support shaft so as to be rotatable in clockwise and counterclockwise directions with the axis of the support shaft as the rotation center. When using the nail clipper, a part of the cutting member protruding from the cutout surface is pulled out. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-248013 A [Patent Document 2] JP 2018-102408 A Summary of the Invention [Problem to be solved by the invention]

[0005] There is a continuing need for nail clippers that improve sharpness, reduce cutting resistance, and cut nails smoothly and cleanly. The nail clippers described in Patent Documents 1 and 2 above have room for improvement in terms of cutting nails smoothly and cleanly. One way to improve the sharpness of nail clippers is to make the cutting edge sharper, but simply making the cutting edge thinner to make it sharper can cause the blade to bend or break.

[0006] In addition, from the perspective of SDGs Goal 12 "Responsible Consumption and Production" - 12.5 "By 2030, substantially reduce waste generation through prevention, reduction, recycling and reuse," there is a growing need for everyday items that are hard to break and can be used continuously. The present invention aims to provide a nail clipper that is one of the products that is not only functional but also durable, in order to contribute to the realization of a sustainable world. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides the following means. In the following description, reference numerals and the like in the drawings may be written in parentheses to facilitate understanding of the invention, but the components of the present invention are not limited to these specific configurations and should be broadly interpreted within the scope of technical understanding of those skilled in the art.

[0008] The nail clipper according to one embodiment of the present invention comprises a first blade body (10) having a first bladed portion (13) at a first tip portion (12) located at the tip, a second blade body (20) having a second bladed portion (23) at a second tip portion (22) located at the tip, and an operating member (30) operated to move the first bladed portion and the second bladed portion closer to or farther from each other. The first tip portion (12) has a blade surface (15) exposed to the outside and a blade back surface (16) located on the back side of the blade surface. The blade back surface (16) is curved so that the angle with respect to the vertical direction increases with distance from the cutting edge at the tip of the first bladed portion, and the angle between the blade surface and the blade back surface at the cutting edge of the first bladed portion is 20° or more and 35° or less.

[0009] The angle between the blade surface and the blade back of the nail clipper with the above configuration is between 20° and 35°, which is sharper than that of conventional nail clippers, and allows the clipper to smoothly cut the nail while reducing the cutting resistance during use. In addition, the blade back is curved rather than straight, and the thickness of the first tip increases as it moves away from the cutting edge, which makes it possible to prevent the blade from bending or breaking. This makes it possible to provide a nail clipper with sufficient performance for cutting nails and increased durability.

[0010] In the above nail clipper, preferably, the angle between the front surface and the back surface of the blade at the cutting edge of the first bladed portion is 27° or more and 33° or less.

[0011] The nail clipper having the above-described configuration allows the user to cut his nails without any particular stress.

[0012] In the nail clipper, the back of the blade is preferably curved in an arc having a radius of curvature of 5 mm or more and 50 mm or less.

[0013] According to the nail clipper having the above-mentioned configuration, the cutting edge can be made sufficiently sharp while ensuring sufficient durability of the cutting edge.

[0014] In the above nail clipper, preferably, the first blade body (10) further has a first main body portion (11) continuing from the first tip portion (12), the first tip portion (12) is bent toward the second blade body side relative to the first main body portion, and the blade surface (15) has a first blade surface (15a) including the cutting edge and extending horizontally in the vertical direction, and a second blade surface (15b) continuing from the first blade surface and extending linearly at an acute angle with respect to the vertical direction, the second blade surface being formed so as to form an angle of 55° or more and 75° or less with respect to the first main body portion.

[0015] In the past, there have been descriptions of nail clippers with curved blade undersides in patent documents, but these are merely conceptual representations in drawings, and no nail clippers have actually adopted a curved blade underside. This is because the usefulness of curved blade undersides has not been recognized in the past, given the difficulties involved in manufacturing the curved blade underside.

[0016] The inventors have found that by adopting a nail clipper shape in which the blade surface is straight and the blade surface is curved as described above, it is possible to provide a configuration that is sufficiently useful even when the difficulties in manufacturing are taken into consideration. With the nail clipper configured as described above, it is possible to provide a nail clipper with improved durability that can prevent the blade body from bending or breaking, while employing a relatively easy manufacturing technique.

[0017] Furthermore, according to the inventors' study, it was found that if the angle of the second cutting edge relative to the first body portion is less than 55°, the thickness of the cutting edge becomes small, which reduces rigidity, causing the cutting edge to bend during use and making it difficult to cut nails. It was also found that if the angle of the second cutting edge is greater than 75°, it becomes difficult to form the cutting edge by press processing. Therefore, by adopting the above-mentioned configuration in which the angle of the second cutting edge relative to the first body portion is between 55° and 75°, it is possible to achieve a configuration that is easy to cut nails and does not cause problems during forming.

[0018] Furthermore, by making the first blade surface extend horizontally in the vertical direction as described above, the first blade body and the second blade body can be sharpened simultaneously, improving the efficiency of the manufacturing process. Also, the nail clipper can be configured to be easy to cut nails when in use.

[0019] In the above nail clipper, preferably, the first blade body further has a first main body portion continuing from the first tip portion, the first tip portion is bent toward the second blade body side relative to the first main body portion, and a blade back connection portion (16b) connecting the blade back and the first main body portion is curved to have a radius of curvature smaller than the radius of curvature of the blade back.

[0020] The nail clipper having the above-described configuration can be relatively easily molded, and can be configured to sufficiently prevent the bent connection portion between the first main body portion and the first tip portion from being damaged by stress. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view of a nail clipper. [Diagram 2] FIG. 2 is a side view of the nail clipper with the cutting edges engaged. [Diagram 3] FIG. 3 is an enlarged view of the vicinity of the cutting edges of the nail clippers when the cutting edges are engaged. [Figure 4] FIG. 4 is a top view of the upper blade body. [Diagram 5] FIG. 5 is an enlarged view of the vicinity of the cutting edge of the upper blade body. [Figure 6] FIG. 6 is an enlarged cross-sectional view of the vicinity of the cutting edge of the upper blade body of the modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] One feature of the nail clipper of the present invention is that the underside of the blade is curved in an arc so that the angle with respect to the vertical direction increases with increasing distance from the cutting edge, and the angle between the front and back of the blade at the cutting edge is between 20° and 35°.

[0023] Hereinafter, a nail clipper according to one embodiment of the present invention will be described in detail with reference to the drawings. However, the embodiment and examples described below are merely examples of the present invention and should not be construed as limiting the technical scope of the present invention. In each drawing, the same components are denoted by the same reference numerals.

[0024] For ease of explanation, in this specification, the direction from the upper blade body 10 side to the lower blade body 20 side on the blade surface side of the upper blade portion 13 of the upper blade body 10 and the lower blade portion 23 of the lower blade body 20 is referred to as the "vertical direction", but the vertical direction here does not refer to the direction of gravity which changes depending on the orientation of the nail clipper 1.

[0025] Fig. 1 to Fig. 3 are diagrams of the nail clipper 1 of this embodiment, Fig. 1 is a perspective view, Fig. 2 is a side view of the cutting edges engaged, and Fig. 3 is an enlarged view of the vicinity of the cutting edges in the same state. Fig. 4 and Fig. 5 are diagrams of the upper blade body 10 constituting the nail clipper 1, Fig. 4 is a top view, and Fig. 5 is an enlarged cross-sectional view of the vicinity of the cutting edges at the center position in the width direction of the upper blade body 10.

[0026] As shown in Figures 1 and 2, the nail clipper 1 comprises an upper blade body 10, a lower blade body 20, and an operating member 30. The operating member 30 comprises a lever 31 and a support shaft 32. The upper blade body 10 and the lower blade body 20 are connected by welding at a connecting portion 11a. The upper blade body 10 and the lower blade body 20 are further connected by a support shaft 32 near their respective tips so that the upper blade body 10 and the lower blade body 20 can move toward and away from each other. The support shaft 32 is a cylindrical member, and the lever 31 is connected so as to be rotatable around the axis of the support shaft 32.

[0027] As shown in Figs. 1 to 4, the upper blade body 10 includes an upper main body portion 11 and an upper tip portion 12. The upper main body portion 11 is plate-shaped. The upper tip portion 12 is formed continuously from the upper main body portion 11 and is bent toward the lower blade body 20 with respect to the upper tip portion 12. The upper tip portion 12 is formed with an upper bladed portion 13 that is sharpened by sharpening. The upper bladed portion 13 has a cutting edge 14 that is the tip of the blade. The upper tip portion 12 has a cutting surface 15 exposed to the outside and a cutting back surface 16 located on the back side of the cutting surface. As shown in Fig. 4, the upper bladed portion 13 of the upper blade body 10 is curved in an arc shape with a recessed center at both ends in the width direction. The radius of curvature of the upper bladed portion 13 is, for example, 28 mm, but may be changed as desired.

[0028] As shown in the enlarged view of the upper blade body 10 in Figure 5, the upper body portion 11 has an outer surface 10a and an inner surface 10b. The inner surface 10b is provided at a position opposite to the lower body portion 21 of the lower blade body 20, and the outer surface 10a is the surface opposite to the inner surface 10b.

[0029] The blade back 16 has a curved portion 16a formed in the region from the cutting edge 14 to the blade back connection portion 16b, and a blade back connection portion 16b connecting the blade back 16 and the inner surface 10b of the upper main body portion 11. The curved portion 16a and the blade back connection portion 16b are curved so that the angle with respect to the vertical direction increases with increasing distance from the cutting edge 14. Specifically, the curved portion 16a is curved in an arc shape, and the radius of curvature is preferably 5 mm or more and 50 mm or less, more preferably 30 mm or less, and even more preferably 15 mm or less, for example 11.3 mm. The blade back connection portion 16b is also curved in an arc shape, and the radius of curvature is 0.1 mm to 2.0 mm, for example 1.0 mm. The radius of curvature of the blade back connection portion 16b is formed to be smaller than the radius of curvature of the curved portion 16a of the blade back 16.

[0030] The blade surface 15 has a first blade surface 15a extending vertically from the cutting edge 14, a second blade surface 15b continuing from the first blade surface 15a, and a third blade surface 15c connecting the second blade surface 15b and the outer surface 10a. The second blade surface 15b extends in a direction forming an acute angle with respect to the vertical direction. The angle θ2 that the second blade surface 15b has with the outer surface 10a of the upper body portion 11 is preferably 55° to 75°, more preferably 60° to 70°, for example 65°. The third blade surface 15c is curved in an arc shape, and the radius of curvature is 1.0 mm to 4.0 mm, for example 2.8 mm.

[0031] The distance L1 between the outer surface 10a and the cutting edge 14 is, for example, not less than 3.0 mm and not more than 6.0 mm, for example, 4.6 mm.

[0032] At the position of the cutting edge 14, the angle θ1 between the blade surface 15 and the blade back surface 16, more specifically, the angle between the first blade surface 15a and the curved portion 16a, is preferably 20° or more and 35° or less, more preferably 27° or more and 33° or less, for example, 30°.

[0033] The angle θ1 between the blade surface 15 and the back surface 16 is measured by measuring the angle between a tangent to the tip of the cutting edge 14 on a curve formed by the back surface 16 in the cross section of the upper blade body 10 and the first blade surface 15a of the blade surface 15.

[0034] The lower blade body 20 has roughly the same shape as the upper blade body 10, but has a slightly different shape due to adjustments for meshing with the upper blade body 10, etc.

[0035] The lower blade body 20 includes a lower main body portion 21 and a lower tip portion 22. The lower main body portion 21 is plate-shaped. The lower tip portion 22 is formed continuously with the lower main body portion 21 and is bent toward the upper blade body 10 relative to the lower main body portion 21. A lower bladed portion 23 that has been sharpened by sharpening is formed on the lower tip portion 22. The lower bladed portion 23 has a cutting edge 24 that is the tip of the blade.

[0036] Here, an outline of a manufacturing method for the nail clippers 1 will be described in order to understand the difference in shape between the upper blade body 10 and the lower blade body 20. As the manufacturing method for nail clippers is well known, a detailed description will be omitted, but the nail clippers 1 are manufactured as follows.

[0037] First, a blade body that will be the base material of the upper blade body 10 and the lower blade body 20 is prepared. This base blade body is common to the upper blade body 10 and the lower blade body 20. The base blade body before processing is slightly different in shape from the upper blade body 10 and the lower blade body 20 that are completed through the following process. Next, the upper blade body 10 and the lower blade body 20 are connected by welding at the connecting portion 11a. Next, the cutting edges 14 and 24 are formed by sharpening the respective tip portions. At this time, the front surfaces of the cutting edges 14 and 24 are formed on the same plane both before and after sharpening. Therefore, the cutting edge 14 of the upper blade body 10 and the cutting edge 24 of the lower blade body 20 can be sharpened simultaneously in a single sharpening process. Next, the cutting edge 14 of the upper blade body 10 and the cutting edge 24 of the lower blade body 20 are slightly misaligned to form a "cover" that prevents the cutting edges from touching each other during use, and the angles of the upper blade body 10 and the lower blade body 20 are adjusted by "blade spreading."

[0038] [Using nail clipper 1] In the state shown in FIG. 1, the lever 31 is laid down, and in the state shown in FIG. 2, the lever 31 is rotated about the support shaft 32 to stand up. When the lever 31 is operated by the user in the standing state shown in FIG. 2 to press the upper body 11 of the upper blade body 10 toward the lower body 21 of the lower blade body 20, the upper tip 12 of the upper blade body 10 and the lower tip 22 of the lower blade body 20 approach each other against the elastic force, and the cutting edges 14 and 24 come into contact with each other. As described above, more precisely, the cutting edges 14 and 24 are slightly misaligned. When the user reduces the force applied to the lever 31, the upper tip 12 of the upper blade body 10 and the lower tip 22 of the lower blade body 20 move away from each other due to the elastic force. That is, the operating member 30 is a member for operating the upper bladed portion 13 of the upper tip 12 and the lower bladed portion 23 of the lower tip 22 so as to move them toward and away from each other.

[0039] [Variations] Fig. 6 is an enlarged view of the vicinity of the cutting edge of the upper blade body 110 of the nail clipper in the modified example, which corresponds to Fig. 5 of the embodiment. Compared to the upper blade body 10 of the embodiment, the cutting back 116 of the modified example, which corresponds to the cutting back 16, differs in the curvature radius of the curved portion 116a and the cutting back connection portion 116b, and the angle with the cutting front surface 15. The differences from the embodiment will be specifically described below.

[0040] The blade back 116 has a curved portion 116a formed in the region from the cutting edge 14 to the blade back connection portion 116b, and the blade back connection portion 116b connecting the blade back 116 to the inner surface 10b of the upper main body portion 11. The curved portion 116a and the blade back connection portion 116b are curved so that the angle with respect to the vertical direction increases with increasing distance from the cutting edge 14. Specifically, the curved portion 116a is curved in an arc, with a radius of curvature of, for example, 7.6 mm. The blade back connection portion 116b is also curved in an arc, with a radius of curvature of, for example, 1.0 mm.

[0041] At the position of the cutting edge 14, the angle θ3 formed between the blade surface 15 and the blade back surface 116, more specifically, the angle θ3 formed between the first blade surface 15a and the curved portion 116a, is, for example, 25°.

[0042] The present invention is not limited to the configurations of the embodiments and modifications, and also includes modifications based on the configurations of the embodiments and modifications.

[0043] [Nail clipper evaluation] The nail clippers 1 of the embodiment, the modified nail clippers, and the reference example nail clippers were prepared and evaluated by several people who actually used them. The reference example nail clippers were prepared with an angle of 40° between the blade surface and the blade back surface. In the following, for the sake of convenience, the nail clippers 1 of the embodiment will be referred to as nail clippers A, the modified nail clippers as nail clippers B, and the reference example nail clippers as nail clippers C.

[0044] The evaluation was carried out by multiple people, who rated the sharpness and cutting quality of the blade when cutting the nails on a four-point scale: 1. good, 2. fair, 3. slightly bad, and 4. bad. The sharpness of the blade was determined by comprehensively judging the cleanness of the cut edge when cutting the nails, the ease of separating the cut nails, and the occurrence of burrs. The sharpness of the blade was determined based on the degree to which the nails could be cut with light force. The sharpness and cutting quality were calculated as the average of the four-point scale. In other words, the lower the value, the higher the evaluation.

[0045] As a result of the above evaluation, nail clipper A had a sharpness of cutting: 1.3 and sharpness: 2.0, nail clipper B had a sharpness of cutting: 1.4 and sharpness: 1.6, and nail clipper C had a sharpness of cutting: 1.8 and sharpness: 2.2. In other words, nail clipper A was rated the highest for sharpness of cutting, and nail clipper B was rated the highest for sharpness. From these evaluation results, it was found that although nail clipper B had the best sharpness, nail clipper A would be preferred by users overall.

[0046] [Features of nail clippers] In the nail clippers of the above-mentioned embodiment and modified example, the blade back 16 is curved so that the angle with respect to the vertical direction increases as it moves away from the cutting edge 14 at the tip of the upper blade portion 13, and the angle between the blade surface 15 and the blade back 16 at the cutting edge 14 of the upper blade portion 13 is configured to be 20° or more and 35° or less. This configuration reduces the cutting resistance during use and allows the nail to be cut smoothly. In addition, since the blade back 16 is curved rather than linear and the thickness of the upper tip portion 12 increases as it moves away from the cutting edge 14, it is possible to prevent the upper blade body 10 from bending or breaking. This makes it possible to provide a nail clipper that has sufficient performance for cutting nails and has increased durability.

[0047] In addition, the angle between the blade surface 15 and the blade back surface 16 is set to 27° or more and 33° or less, allowing the user to cut their nails without any stress.

[0048] In addition, the back side of the blade 16 is curved into an arc with a radius of curvature of 5 mm or more and 50 mm or less, so that the durability of the cutting edge 14 can be sufficiently ensured while the cutting edge 14 is made sufficiently sharp.

[0049] Additionally, the upper tip portion 12 of the upper blade body 10 is bent toward the lower blade body 20 relative to the upper main body portion 11. In the blade surface 15, the second blade surface 15b, which is continuous with the first blade surface 15a that includes the cutting edge 14 and extends horizontally in the vertical direction and extends linearly at an acute angle to the vertical direction, is formed to form an angle θ2 of 55° to 75° with the upper main body portion 11. With this configuration, it is possible to prevent the blade body from bending or breaking, and it is possible to provide a nail clipper with increased durability using a relatively simple manufacturing technique.

[0050] In addition, since the blade back connection portion 16b is curved to have a radius of curvature smaller than the radius of curvature of the curved portion 16a of the blade back 16, it is relatively easy to form and is configured in a way that can sufficiently prevent the curved connection portion between the upper main body portion 11 and the upper tip portion 12 from being damaged due to stress.

[0051] As explained in the embodiment, the above configurations are applied not only to the upper blade body 10 but also to the lower blade body 20, and it is more preferable to configure the upper blade body 10 and the lower blade body 20 as described above. However, a certain degree of effect can be obtained even if the above configuration is adopted only for the upper blade body 10 or the lower blade body 20. [Explanation of symbols]

[0052] 1. Nail clippers 10, 110...upper blade body 11...Upper body part 12…Top tip 13…Upper blade part 14…Cutting edge 15...Blade surface 16, 116…Back of the blade 16a, 116a...curved portion 16b, 116b...Blade back connection part 20…Lower blade 21…Lower body part 22...Lower tip 23…Lower blade part 24…Edge 30...Operation member 31... Lever 32…Spindle

Claims

1. A first blade body having a first cutting edge portion at the first tip located at the tip, A second blade body having a second cutting edge at the second tip located at the tip, The device comprises an operating member for operating the first cutting portion and the second cutting portion to move closer to and further apart from each other, The first tip portion has a blade surface that is exposed to the outside and a blade back located on the back side of the blade surface, and the blade back is curved such that the angle with respect to the vertical increases as it moves away from the cutting edge of the tip of the first cutting portion. In the cutting edge of the first cutting portion, the angle between the front surface of the blade and the back surface of the blade is 20° or more and 35° or less. The blade surface has a first blade surface that includes the cutting edge and extends horizontally in the vertical direction. Nail clippers.

2. In the cutting edge of the first cutting portion, the angle between the front surface of the blade and the back surface of the blade is 27° or more and 33° or less. The nail clipper according to claim 1.

3. The back of the blade is formed in an arc shape with a radius of curvature of 5 mm or more and 50 mm or less. The nail clipper according to claim 1.

4. The first blade further has a first main body portion that is continuous with the first tip portion, The first tip portion is bent toward the second blade portion relative to the first main body portion. The blade surface has a second blade surface that is continuous with the first blade surface and extends linearly at an acute angle with respect to the vertical direction. The second blade surface is formed to form an angle of 55° to 75° with respect to the first main body. The nail clipper according to claim 1.

5. The first blade further has a first main body portion that is continuous with the first tip portion, The first tip portion is bent toward the second blade portion relative to the first main body portion. The blade back connecting portion connecting the blade back and the first main body portion is formed in a curved shape having a radius of curvature smaller than the radius of curvature of the blade back. The nail clipper according to claim 1.

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