Screw fastening structure

Abstract

To provide a screw fastening structure that allows screw fastening with a small amount of rotation.SOLUTION: Provided is a screw fastening structure that connects a first member having a male threaded portion at one end and a second member having a female threaded portion at one end. The male threaded portion of the first member has one or more male threads having a length of 1 / (2n) circumference arranged n pieces (n: a natural number) in one circumference, at equal intervals in the circumferential direction. The female threaded portion of the second member has one or more female threads having a length equal to or less of 1 / (2n) circumference arranged n pieces in one circumference, at equal intervals in the circumferential direction. Alternatively, the male threaded portion of the first member has one or more male threads having a length equal to or less of 1 / (2n) circumference, arranged n pieces in one circumference, at equal intervals in the circumferential direction. The female threaded portion of the second member has one or more female threads having a length of 1 / (2n) circumference arranged n pieces in one circumference, at equal intervals in the circumferential direction.SELECTED DRAWING: Figure 3

Description

Technical Field

[0003] , , , , , , , , , ,

[0004] , , , , , ,

[0001] <000,004>The present invention relates to a screwing structure used for writing instruments such as ballpoint pens, mechanical pencils, and signature pens, as well as for cosmetics such as eyeliner pens, general storage containers composed of containers and lids, and handles of various tools.

Background Art

[0002] Conventionally, the screwing structure used for writing instruments, cosmetics, storage containers, handles of tools, etc. is an ordinary screwing structure provided with at least one spiral screw. To fasten the screw, it is necessary to rotate the member provided with the screw many times, which may be troublesome for the user and also a factor reducing productivity during manufacturing. Also, if the screw is tightened too much, the thread may be deformed or damaged, causing the screw to spin freely and unable to be fastened. 5] Furthermore, the screw is a means of fixing by friction, and if tightening and loosening are repeated, the fastened screw may become loose easily. Therefore, screws that can be fastened with a small amount of rotation and screws provided with a stopper or anti-loosening means at the fastening end of the screw have been proposed. (See Patent Document 1)

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The screw fastening structure described in Patent Document 1 has a male thread that extends for one full turn, and fastening the screw requires a minimum of one turn and a maximum of two turns, which is still a large amount of rotation. Moreover, since the contact surfaces of the two stopper pieces are perpendicular to the direction of rotation, there is a considerable possibility that they will deform or break and spin freely if a large fastening force is applied. Furthermore, the return prevention piece that prevents the screw from loosening is a thin protrusion that extends outward, which raises concerns about durability when used as a screw fastening means for containers and lids that are opened and closed many times.

[0005] Therefore, the object of the present invention is to provide a screw tightening structure that can tighten screws with a small amount of rotation. Another objective is to provide a screw tightening structure that can reliably prevent screws from spinning freely due to overtightening. Furthermore, the objective is to provide a screw fastening structure that reliably prevents screws from loosening and also features a highly durable anti-loosening mechanism. [Means for solving the problem]

[0006] To solve the aforementioned problems, the present invention has the following configuration. In a screw fastening structure that connects a first member having a male threaded portion at one end and a second member having a female threaded portion at one end, The male thread portion of the first member has at least one thread of a male screw having a length of 1 / (2n) of the circumference, arranged at equal intervals in the circumferential direction, with n threads (n: a natural number) per circumference, and the female thread portion of the second member has at least one thread of a female screw having a length of 1 / (2n) or less per circumference, arranged at equal intervals in the circumferential direction. the law of nature, A first slider portion is formed in conjunction with the tip side surface of the tip side surface of the tip of the tip of the male screw portion at the leading edge, which has a curved shape that curves away from the leading edge as it moves from the downstream to the upstream side in the rotational direction when fastening, and / or a second slider portion is formed in conjunction with the tip side surface of the tip of the tip of the female screw portion at the leading edge, which has a curved shape that curves away from the leading edge as it moves from the downstream to the upstream side in the rotational direction when fastening, Or, The male thread portion of the first member has at least one thread of n male threads, each having a length of 1 / (2n) or less, arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of n female threads, each having a length of 1 / (2n) in the circumferential direction, arranged at equal intervals in the circumferential direction. the law of nature, A first slider portion is formed in conjunction with the tip side surface of the tip side surface of the tip of the tip of the female thread on the leading edge side of the female thread, which has been arranged at equal intervals in the circumferential direction, and / or a second slider portion is formed in conjunction with the tip side surface of the tip of the tip of the male thread on the leading edge side of the male thread, which has been arranged at equal intervals in the circumferential direction, and / or a second slider portion is formed in conjunction with the tip side surface of the tip of the tip of the tip of the male thread, which has been arranged in conjunction with the tip side surface of the tip of the tip of the male thread, which has been arranged in conjunction with the tip side surface of the tip of the male thread, which has been arranged in conjunction with the tip side surface of the tip of the male thread, which has been arranged at equal intervals in the circumferential direction, and A screw-tightening structure characterized by the following: Furthermore, the present invention comprises the following configurations. In a screw fastening structure that connects a first member having a male threaded portion at one end and a second member having a female threaded portion at one end, The male thread portion of the first member has at least one thread of a male screw having a length of 1 / (2n) of the circumference, arranged at equal intervals in the circumferential direction, with n threads (n: a natural number) per circumference, and the female thread portion of the second member has at least one thread of a female screw having a length of 1 / (2n) or less per circumference, arranged at equal intervals in the circumferential direction, A first occlusal portion is formed at the upstream end of at least one thread of the male screw, which has a length of 1 / (2n) of the circumference and is arranged at equal intervals in the circumferential direction, in the male screw portion, wherein at least one thread of the male screw at the rearmost end has a length of 1 / (2n) of the circumference and is arranged at equal intervals in the circumferential direction, extending in the direction of rotation of the male screw and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation is wedge-shaped. A second occlusal portion is formed at the downstream end of at least one thread of the female screw, which has a length of 1 / (2n) of the circumference or less and is arranged at equal intervals in the circumferential direction, in the female screw portion, wherein at least one thread of the female screw, which has a length of 1 / (2n) of the circumference or less and is arranged at equal intervals in the circumferential direction, extends in the direction of rotation of the female screw and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation is wedge-shaped. Or, The male thread portion of the first member has at least one thread of n male threads, each having a length of 1 / (2n) or less, arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of n female threads, each having a length of 1 / (2n) in the circumferential direction, arranged at equal intervals in the circumferential direction. In the female thread portion, at least one thread of the female thread, each having a length of 1 / (2n) of the circumference and n threads per circumference, is arranged at equal intervals in the circumferential direction. A first occlusal portion is formed at the upstream end of at least one thread of the female thread at the rearmost end, extending in the direction of rotation of the female thread and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation is wedge-shaped. In the male thread portion, at least one thread of the male thread, each having a length of 1 / (2n) of the circumference or less and n threads per circumference, is arranged at equal intervals in the circumferential direction. A second occlusal portion is formed at the downstream end of at least one thread of the male thread at the furthest end, extending in the direction of rotation of the male thread and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation is wedge-shaped. When the male screw portion and the female screw portion are fastened together, the first occlusal portion and the second occlusal portion occlude with each other. A screw-tightening structure characterized by the following: [Effects of the Invention]

[0007] The present invention enables fastening with a minimum rotation of 1 / (2n) turns and a maximum of 3 / (2n) turns by fastening a first member having at least one male or female thread with a length of 1 / (2n) turns per circumference arranged at equal intervals in the circumferential direction, and a second member having at least one female or male thread with a length of 1 / (2n) turns or less per circumference arranged at equal intervals in the circumferential direction. Furthermore, this invention can reliably prevent screws from spinning freely due to overtightening. Furthermore, the present invention can reliably prevent screws from loosening. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of a ballpoint pen 1 according to Embodiment 1 of the present invention. [Figure 2] This is a perspective view of the ballpoint pen 1 according to Embodiment 1 of the present invention, disassembled into two parts: a front cylindrical case 21 and a rear cylindrical case 22. [Figure 3] These are a front view and a side view of the front cylindrical case 21 of the ballpoint pen 1 according to Embodiment 1 of the present invention. [Figure 4] This is an enlarged perspective view of the male screw portion 3 of the front cylindrical case 21 of the ballpoint pen 1 according to Embodiment 1 of the present invention. [Figure 5]It is a longitudinal sectional view of the rear cylindrical case 22 of the ballpoint pen 1 according to Embodiment 1 of the present invention. [Figure 6] It is a partially cut-away enlarged perspective view of the female screw portion 4 of the rear cylindrical case 22 of the ballpoint pen 1 according to Embodiment 1 of the present invention. [Figure 7] It is a sectional view taken along line VII-VII of FIG. 1. [Figure 8] It is a sectional view taken along line VIII-VIII of FIG. 1. [Figure 9] It is a diagram showing the state of fastening of the male screw portion 3 and the female screw portion 4 of the ballpoint pen 1 according to Embodiment 1 of the present invention. [Figure 10] It is a perspective view of one part 5 obtained by disassembling the handle of the tool according to Embodiment 2 of the present invention. [Mode for Carrying Out the Invention]

[0009] [Embodiment 1] Hereinafter, the screw fastening structure according to Embodiment 1 of the present invention will be described by exemplifying a ballpoint pen 1 which is a writing instrument, with reference to the drawings. In the following description, the same reference numerals in different figures indicate parts having the same function, and duplicate descriptions in each figure are omitted as appropriate.

[0010] [Overall Structure of Ballpoint Pen] FIG. 1 is a perspective view of a ballpoint pen 1 according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view of the ballpoint pen 1 according to Embodiment 1 of the present invention disassembled into two parts, a front cylindrical case 21 and a rear cylindrical case 22. The ballpoint pen 1 has a cylindrical case 2 composed of a front cylindrical case 21 and a rear cylindrical case 22. Inside the cylindrical case 2, a refill and a knock mechanism (both not shown) are housed. The front cylindrical case 21 and the rear cylindrical case 22 are integrated to form the cylindrical case 2 by fastening a male screw portion 3 provided on the front cylindrical case 21 and a female screw portion 4 provided on the rear cylindrical case 22.

[0011] [Structure of Male Screw Portion] Figure 3 is a front view and a side view of the front cylindrical case 21 of the ballpoint pen 1 according to Embodiment 1 of the present invention, and Figure 4 is an enlarged perspective view of the male screw portion 3 of the front cylindrical case 21 of the ballpoint pen 1 according to Embodiment 1 of the present invention. The front cylindrical case 21 has a reduced outer diameter at its rear end, and a protruding portion 211 with a male threaded portion 3 is provided via a stepped portion 212. The male threaded portion 3 has two male threads 31, a first slider portion 32, a first occlusal portion 33, and a first rib 34. Note that the male threads 31 are not limited to two threads; they may have one thread or three or more threads.

[0012] The male screw 31 has two pairs of male threads 311, each with a length of 1 / 4 of the circumference, arranged axially on the front cylindrical case 21. These pairs of male threads 311 are provided in two locations circumferentially, separated by a gap 312 that is 1 / 4 of the circumference. The gap refers to the unthreaded portion between the threads in the circumferential direction. (The same applies hereafter.)

[0013] The first slider portion 32 is provided at the upstream end of each pair of male threads 311 in the rotational direction when the screws are fastened, so as to fill a portion of the gap 312. The first slider portion 32 is formed to connect with the tip side surface of the screw thread 3111 on the tip side in the insertion direction when fastening the screw among the pairs of male screw threads 311, and is a convex portion with a curved surface 321 that curves away from the tip side in the insertion direction as it goes from the downstream side to the upstream side in the rotation direction when fastening the screw.

[0014] The first occlusal portion 33 is a protrusion extending axially from the front cylindrical case 21, connected to the rear end of the first slider portion 32, at the upstream end in the rotational direction of the screw fastening of the screw thread 3112 at the rear end in the insertion direction of each pair of male screw threads 311 during screw fastening. As shown in Figure 7, it has a wedge-shaped first occlusal projection 331 that protrudes toward the downstream side in the rotational direction.

[0015] The first rib 34 extends axially from the front cylindrical case 21 at a position spaced apart from the thread 3112 at the rear end of the insertion direction, and at a position spaced apart from the first occlusal projection 331 at the downstream side of the rotation direction when the screw is fastened to the first occlusal projection 331.

[0016] [Structure of the female screw part] Figure 5 is a longitudinal cross-sectional view of the rear cylindrical case 22 of the ballpoint pen 1 according to Embodiment 1 of the present invention, and Figure 6 is a partially cut and enlarged perspective view of the female screw portion 4 of the rear cylindrical case 22 of the ballpoint pen 1 according to Embodiment 1 of the present invention. The rear cylindrical case 22 has a female screw portion 4 formed on the inner circumferential surface at the tip end. The female thread portion has two female threads 41, a second slider portion 42, a second occlusal portion 43, and a second rib 44. Note that the female threads 41 are not limited to two; they may have one or three or more threads.

[0017] The female thread 41 has a pair of female threads 411, each having two female threads that are less than or equal to 1 / 4 of the circumference and are provided in the axial direction of the rear cylindrical case 22. These pairs of female threads 411 are provided in two locations in the circumferential direction, separated by gaps 412 that are more than 1 / 4 of the circumference. The female thread pairs 411 and the gaps 412 are provided so that the combined length of the female thread pairs 411 and the gaps 412 equals 1 / 2 of the circumference.

[0018] The second slider portion 42 is provided so as to project toward the insertion end in the insertion direction, continuously from the tip side surface of the screw thread 4111 on the tip side in the insertion direction of each female screw thread pair 411, and the tip side surface in the insertion direction is a convex portion with a curved surface 421 formed thereon, which curves away from the tip side in the insertion direction as it goes from the downstream side to the upstream side in the rotation direction when the screw is fastened.

[0019] The second occlusal portion 43 is provided at the tip of the thread 4111 in the insertion direction when screwing in each female thread pair 411, and at the downstream end in the rotation direction when screwing in the second slider portion 42. Furthermore, as shown in Figure 7, the second occlusal portion 43 has a wedge-shaped second occlusal projection 431 that protrudes toward the downstream side in the rotational direction.

[0020] The second rib 44 extends axially from the rear cylindrical case 22, spaced apart from the thread 4112 at the rear end of the insertion direction, and spaced apart from the second occlusal projection 431 on the downstream side of the rotational direction when the screw is fastened.

[0021] [Structure of the occlusal area] Figure 7 is a cross-sectional view taken along line VII-VII in Figure 1, showing the occlusal structure of the first occlusal portion 33 and the second occlusal portion 43. The first occlusal projection 331 of the male screw portion 3 and the second occlusal projection 431 of the female screw portion 4 have similar angles at their tips, forming acute angles of 30° to 60°, respectively. This structure ensures that even when a large fastening force is applied, the male thread pair 311 and female thread pair 411 do not break or deform, thus preventing the male thread 31 and female thread 41 from spinning freely. If the angle of the tips of the first occlusal projection 331 and the second occlusal projection 431 is less than 30°, the first occlusal projection 331 and the second occlusal projection 431 will bite together firmly, but the first occlusal projection 331 and the second occlusal projection 431 themselves will become thin, making them prone to breakage when a large fastening force is applied. Conversely, if these tip portions are greater than 60°, when a large fastening force is applied, the first occlusal projection 331, the second occlusal projection 431, the front cylindrical case 21, and the rear cylindrical case 22 will deform, causing the male screw 31 and female screw 41 to overlap each other, making it easier for the screw to spin freely.

[0022] [Rib structure] Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 1, showing the occlusal structure of the first rib 34 and the second rib 44. The first rib 34 extends axially from the front cylindrical case 21, spaced apart from the threaded groove 3112 at the rear end of the insertion direction, and spaced apart from the first occlusal projection 331 on the downstream side of the rotational direction when the screw is fastened to the first occlusal projection 331. The upstream side of the first rib 34 in the rotational direction when the screw is fastened is steeper than the downstream side. This shape allows the downstream surface of the first rib 34 to pass over the second rib 44 during fastening, thus requiring less rotational force. Conversely, when the screw loosens, the steep upstream surface of the first rib 34 must pass over the second rib 44, thus preventing the screw from loosening with less force.

[0023] Furthermore, the upstream side of the second rib 44 in the direction of rotation when the screw is fastened may be steeper than the downstream side, and the upstream side of the first rib 34 and the second rib 44 in the direction of rotation when the screw is fastened may each be steeper than the downstream side. Furthermore, the locations where the first rib 34 and the second rib 44 are formed can be any location where the first rib 34 and the second rib 44 can overcome each other during fastening, and where fastening of the male and female threads is not hindered.

[0024] [Screw fastening] Figure 9 shows the fastening of the male screw portion 3 and the female screw portion 4 of the ballpoint pen 1 according to Embodiment 1 of the present invention. When the protruding portion 211 of the front cylindrical case 21 is inserted into the front end of the rear cylindrical case 22, as shown in Figure 9(a), the front end surface of the thread 3111 on the insertion end side of the male screw 31 and the front end surface of the second slider portion 42 of the female screw 41 come into contact with each other. Subsequently, when the front cylindrical case 21 and the rear cylindrical case 22 are rotated relative to each other, the tip surface of the thread 3111 on the insertion side and the tip surface of the second slider part 42 slide against each other and advance downstream in the rotational direction. Then, as shown in Figure 9(b), the curved surface 321 of the first slider part 32 and the curved surface 421 of the second slider part 42 come into contact with each other, and the male thread part 3 and the female thread part 4 also advance in the insertion direction. At this time, the contact between the curved surfaces 321 and 421 allows for a smooth change in the direction of travel from the rotational direction to the insertion direction, thereby enabling a smooth screw fastening operation. As the entire female thread portion 4 advances into the gap 312 of the male thread portion 3, the male thread portion 3 and the female thread portion 4 each advance further in the insertion direction, as shown in Figure 9(c).

[0025] As shown in Figure 9(d), when the tip of the rear cylindrical case 22 comes into contact with the stepped portion 212 of the front cylindrical case 21, its advance in the insertion direction stops. In this state, the thread 4112 on the rear end side in the insertion direction of the female thread portion 4 is positioned to fit between the two threads 3111 and 3112 of the male thread portion 3, and the thread 3112 on the rear end side in the insertion direction of the male thread portion 3 is positioned to fit between the two threads 4111 and 4112 of the female thread portion 4. Furthermore, as it is rotated, as shown in Figure 9(e), the thread 4112 on the rear end side in the insertion direction of the female thread portion 4 enters between the two threads 3111 and 3112 of the male thread portion 3, and the thread 3112 on the rear end side in the insertion direction of the male thread portion 3 enters between the two threads 4111 and 4112 of the female thread portion 4. Finally, as shown in Figure 9(f), the first rib 34 of the male threaded portion 3 and the second rib 44 of the female threaded portion 4 overcome each other, causing the first occlusal portion 33 of the male threaded portion 3 and the second occlusal portion 43 of the female threaded portion 4 to interlock and stop, completing the fastening of the male threaded portion 3 and the female threaded portion 4.

[0026] In Figure 9, from the insertion of the male threaded portion 3 into the female threaded portion 4 (Figure 9(a)) to the completion of fastening (Figure 9(f)), a rotation of slightly less than 3 / 4 of a turn is required. Furthermore, when the protrusion 211 of the front cylindrical case 21 is inserted into the front end of the rear cylindrical case 22, if the downstream end in the rotational direction of the front end face of the male thread pair 311 of the male screw 31 and the downstream end in the rotational direction of the front end face of the second slider portion 42 of the female screw 41 come into contact even more tightly than shown in Figure 9(a), a maximum rotation of approximately 3 / 4 of a turn will be required. Conversely, when the protruding portion 211 of the front cylindrical case 21 is inserted into the front end of the rear cylindrical case 22, if the downstream end of the pair of male threads 311 of the male screw 31 and the downstream end of the pair of female threads 411 of the female screw 41 barely touch, and the pair of female threads 411 of the female screw portion 4 fits into the gap 312 of the male screw 31, then the minimum amount of rotation required is approximately 1 / 4 of a turn.

[0027] [Example 1] The above embodiment 1 was a combination of a male threaded portion 3 having a male thread groove that is 1 / 4 of the circumference and a female threaded portion 4 having a female thread groove that is 1 / 4 of the circumference or less. However, the opposite combination is also possible: a female threaded portion having a female thread groove that is 1 / 4 of the circumference and a male threaded portion having a male thread groove that is 1 / 4 of the circumference or less. In this modified example 1, the female screw portion is configured to have a first slider portion, a first occlusal portion, and a second rib, while the male screw portion is configured to have a second slider portion, a second occlusal portion, and a first rib.

[0028] Embodiment 1 and its modification 1 are summarized as follows: The screw portion having a threaded groove that extends for 1 / 4 of the circumference has a first slider portion and a first occlusal portion, and the screw portion having a threaded groove that extends for less than 1 / 4 of the circumference has a second slider portion and a second occlusal portion, with the male screw portion having a first rib and the female screw portion having a second rib.

[0029] [Differentiation 2] In the above embodiment 1, the male thread portion 3 had two male threads with a length of 1 / 4 of a turn, separated by a gap 312 of 1 / 4 of a turn, and the female thread portion 4 had two female threads with a length of less than 1 / 4 of a turn, separated by a gap 412 of 1 / 4 of a turn or longer. However, in addition, the male thread portion may have three male threads with a length of 1 / 6 of a turn, separated by a gap of 1 / 6 of a turn, and the female thread portion may have three female threads with a length of less than 1 / 6 of a turn, separated by a gap of 1 / 6 of a turn or longer. Note that the length of the female threads with a length of less than 1 / 6 of a turn and the length of the gaps of 1 / 6 of a turn or longer are combined to form a length of 1 / 3 of a turn.

[0030] In other words, to generalize, in the male threaded section, where n is a natural number, male threads with a length of 1 / (2n) circumference should be provided at n locations with gaps of 1 / (2n) circumference, and in the female threaded section, female threads with a length of 1 / (2n) or less circumference should be provided at n locations with gaps of 1 / (2n) or more circumference. Note that the length of the female threads with a length of 1 / (2n) or less circumference and the length of the gaps of 1 / (2n) or more circumference should be combined to form a total length of 1 / n circumference. Conversely, in the female thread section, female threads with a length of 1 / (2n) circumference should be provided at n locations via gaps of 1 / (2n) circumference, and in the male thread section, male threads with a length of 1 / (2n) circumference or less should be provided at n locations via gaps of 1 / (2n) circumference or more. Note that the length of the male threads with a length of 1 / (2n) circumference or less and the length of the gaps of 1 / (2n) circumference or more should be combined to form a total length of 1 / n circumference.

[0031] While the lengths of the male thread and its gap, and the female thread and its gap, are given as 1 / 2n of the circumference, they do not necessarily have to be the values ​​shown in this formula. They may deviate from this value, but the length of the male thread and its gap, and the length of the female thread and its gap, should be set to 1 / n.

[0032] In addition, the amount of rotation during fastening in Modification 2 is approximately 1 / (2n) rotations at the minimum and approximately 3 / (2n) rotations at the maximum. Furthermore, if n is small, the amount of rotation required for fastening increases, and conversely, if n is large, the length of each screw becomes too small, resulting in weaker fastening force and increased susceptibility to breakage and deformation. Therefore, although it depends on the size of the male and female screw parts, an optimal value for n is around 2 to 4.

[0033] In this modified version 2, the threaded portion having a thread groove with a length of 1 / (2n) circumference has a first slider portion and a first occlusal portion, and the threaded portion having a thread groove with a length of 1 / (2n) circumference or less has a second slider portion and a second occlusal portion, and the male threaded portion has a first rib and the female threaded portion has a second rib. Conversely, a screw portion having a threaded groove with a length of 1 / (2n) circumference may have a second slider portion and a first occlusal portion, and a screw portion having a threaded groove with a length of 1 / (2n) circumference or less may have a first slider portion and a second occlusal portion, with the male screw portion having a first rib and the female screw portion having a second rib.

[0034] [Difference 3] Furthermore, in the male threaded portion, where n is a natural number, male threads with a length of 1 / (2n+1) turns or less may be provided at (n+1) locations via gaps of n / ((2n+1)(n+1)) turns or more. Similarly, in the female threaded portion, female threads with a length of n / ((2n+1)(n+1)) turns may be provided at (n+1) locations via gaps of 1 / (2n+1) turns. Note that the length of the male threads with a length of 1 / (2n+1) turns or less and the length of the gaps of n / ((2n+1)(n+1)) turns or more are provided so that the total length is 1 / (n+1) turns. For example, when n=2, the male thread section has three male threads with a length of 1 / 5 of a turn or less, separated by gaps of 2 / 15 of a turn or more, and the female thread section has three female threads with a length of 2 / 15 of a turn, separated by gaps of 1 / 5 of a turn. Conversely, in the male threaded portion, where n is a natural number, male threads with a length of 1 / (2n+1) circumference may be provided at (n+1) locations via gaps of n / ((2n+1)(n+1)) circumferences, and in the female threaded portion, female threads with a length of n / ((2n+1)(n+1)) circumferences or less may be provided at (n+1) locations via gaps of 1 / (2n+1) circumferences or more. Note that the length of the female threads with a length of n / ((2n+1)(n+1)) circumferences or less and the length of the gaps of 1 / (2n+1) circumferences or more are provided so that the total length is 1 / (n+1) circumferences.

[0035] Furthermore, in the female thread section, female threads with a length of 1 / (2n+1) turns or less may be provided at (n+1) locations via gaps of n / ((2n+1)(n+1)) turns or more, where n is a natural number. Similarly, in the male thread section, male threads with a length of n / ((2n+1)(n+1)) turns may be provided at (n+1) locations via gaps of 1 / (2n+1) turns. Note that the length of the female threads with a length of 1 / (2n+1) turns or less and the length of the gaps of n / ((2n+1)(n+1)) turns or more are provided so that the total length is 1 / (n+1) turns. Conversely, in the female thread section, female threads with a length of 1 / (2n+1) circumference may be provided at (n+1) locations via gaps of n / ((2n+1)(n+1)) circumferences, and in the male thread section, male threads with a length of n / ((2n+1)(n+1)) circumferences or less may be provided at (n+1) locations via gaps of 1 / (2n+1) circumference or more. Note that the length of the male threads with a length of n / ((2n+1)(n+1)) circumference or less and the length of the gaps of 1 / (2n+1) circumference or more are provided so that the total length is 1 / (n+1) circumference.

[0036] While the lengths of the male thread and its gap, and the female thread and its gap, are given as 1 / (2n+1) turns and n / ((2n+1)(n+1)) turns, the values ​​do not have to be those shown in this formula and may deviate from these values, but the length of the male thread and its gap, and the length of the female thread and its gap, should be set to 1 / (n+1).

[0037] In addition, the amount of rotation during fastening in Modification 3 is approximately 1 / (2n+1) turns at the minimum and approximately (3n+2) / ((2n+1)(n+1)) turns at the maximum. Furthermore, if n is small, the amount of rotation required for fastening increases, and conversely, if n is large, the length of each screw becomes too small, resulting in weaker fastening force and increased susceptibility to breakage and deformation. Therefore, although it depends on the size of the male and female screw parts, an optimal value for n is around 2 to 4.

[0038] In this modified example 3, the threaded portion having a threaded groove with a length of 1 / (2n+1) turns or less has a first slider portion and a first occlusal portion, and the threaded portion having a threaded groove with a length of n / ((2n+1)(n+1)) turns or less has a second slider portion and a second occlusal portion, and the male threaded portion has a first rib and the female threaded portion has a second rib. Conversely, a screw portion having a threaded groove with a length of 1 / (2n+1) or less may form the second slider portion and the first occlusal portion, while a screw portion having a threaded groove with a length of n / ((2n+1)(n+1)) or less may form the first slider portion and the second occlusal portion, with the male screw portion having the first rib and the female screw portion having the second rib.

[0039] [Other examples of Embodiment 1] The above embodiment 1 is an example in which a screw fastening structure is applied to the connection of two halves, front and back, of the cylindrical case 2 of the ballpoint pen 1. However, it may also be applied to a ballpoint pen having a cylindrical case and a tip case, in which the cylindrical case and the tip case are detachable. In addition, it may also be applied to a structure for attaching a cap to the tip of the cylindrical case with screws, or a structure for detachably screwing a member to the rear end of the cylindrical case, etc.

[0040] Furthermore, the writing instrument is not limited to ballpoint pens; other writing instruments such as mechanical pencils and felt-tip pens are also acceptable. Furthermore, Embodiment 1 can be applied not only to writing instruments as described above, but also to cosmetic tools such as eyeliner pens, storage containers consisting of a lid (cap) and a container, and so on.

[0041] [Embodiment 2] Embodiment 1 had a threaded portion at one end of a single member, while Embodiment 2 has threaded portions at both ends of a single member. Hereinafter, with reference to the drawings, the screw fastening structure of Embodiment 2 according to the present invention will be described using the handle (grip, handle, or grip) of a tool (such as a mop or brush) as an example. Figure 10 is a perspective view showing one disassembled part 5 of the handle of a tool according to Embodiment 2 of the present invention.

[0042] Component 5 has a male threaded portion 3 at one end and a female threaded portion 4 at the other end. The male threaded portion 3 and the female threaded portion 4 are the same as those in Embodiment 1 or its modified versions 1 to 3, respectively. Connect multiple of these parts 5 together to assemble a long handle. Furthermore, a member having a male threaded portion at one end, such as the front cylindrical case 21 of Embodiment 1, may be connected to one end of a long handle formed by linking multiple parts 5, and a member having a female threaded portion at one end, such as the rear cylindrical case 22 of Embodiment 1, may be connected to the other end.

[0043] [Differentiation Example 4] In Embodiment 2, the component 5 had a male threaded portion 3 at one end and a female threaded portion 4 at the other end, but it may also have male threaded portions at both ends, or female threaded portions at both ends.

[0044] [Other examples of Embodiment 2] Embodiment 2 is not limited to the handles of the tools described above, but can also be applied as a structure for disassembling into shorter members in long objects such as pointers and antennas, rods for hanging things like hangers, rods for supporting shelves, and rod-shaped members for supporting things like selfie sticks.

[0045] Although Embodiments 1 and 2 of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design changes, etc., that do not depart from the spirit of the present invention are also included. Furthermore, the aforementioned embodiments can be combined by utilizing each other's technologies, as long as there are no particular contradictions or problems in their purpose, configuration, etc.

[0046] [Other embodiments of the invention] (1) In a screw fastening structure that connects a first member having a male threaded portion at one end and a second member having a female threaded portion at one end, The male thread portion of the first member has at least one thread of male screws, each having a length of 1 / (2n) of the circumference, arranged at equal intervals in the circumferential direction, with n threads per circumference (n: a natural number). The female thread portion of the second member has at least one thread of female screws, each having a length of 1 / (2n) or less of the circumference, arranged at equal intervals in the circumferential direction, with n threads per circumference. Or, The male thread portion of the first member has at least one thread of n male threads, each having a length of 1 / (2n) or less, arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of n female threads, each having a length of 1 / (2n) in the circumferential direction, arranged at equal intervals in the circumferential direction. A screw-tightening structure characterized by the following: (2) The male thread portion, in which at least one thread of the male thread having a length of 1 / (2n) of one circumference is arranged at equal intervals in the circumferential direction, and the female thread portion, in which at least one thread of the female thread having a length of 1 / (2n) of one circumference is arranged at equal intervals in the circumferential direction, each has a first slider portion formed in a curved shape at the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the rotational direction when fastened, which curves away from the tip side surface as you go from the downstream side to the upstream side in the rotational direction. and / or, The female thread portion, in which at least one thread of the female thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, and the male thread portion, in which at least one thread of the male thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, is connected to the tip surface of the first thread of the female thread and the first thread of the male thread at the leading edge, respectively, and the tip surface is formed in a curved shape that curves away from the leading edge as it moves from the downstream side to the upstream side in the rotational direction during fastening. The screw fastening structure described in (1) above, characterized in that (3) In the male threaded portion, at least one thread of a male screw having a length of 1 / (2n) of the circumference per circumference is arranged at equal intervals in the circumferential direction, and in the female threaded portion, at least one thread of a female screw having a length of 1 / (2n) of the circumference per circumference is arranged at equal intervals in the circumferential direction, a first occlusal portion is formed at the upstream end of at least one thread of the male screw and one thread of the female screw at the rearmost end in the direction of rotation when fastened, extending in the direction of rotation axis of the male and female screws, and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. In the female thread portion, at least one thread of the female thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, and in the male thread portion, at least one thread of the male thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, a second occlusal portion is formed at the downstream end of at least one thread of the female thread and one thread of the male thread, each extending in the direction of the rotation axis of the female thread and the male thread, and having a wedge shape when viewed in cross-section in the direction of the rotation axis. The screw fastening structure according to (1) or (2), characterized in that the first occlusal portion and the second occlusal portion occlude with each other when the male screw portion and the female screw portion are fastened together. (4) A first rib is formed on the outer surface on which the male thread is formed, extending in the direction of the rotation axis of the male thread. A second rib is formed on the inner circumferential surface where the female thread is formed, extending in the direction of the rotation axis of the female thread. A screw fastening structure according to any one of (1) to (3) above, characterized in that when the male screw portion and the female screw portion are fastened together, the first rib and the second rib overcome each other and engage. (5) A writing instrument having a screw-fastening structure as described in any one of (1) to (4), characterized in that the first member and the second member are one and the other of two detachable cylindrical cases of a writing instrument, respectively. (6) A lidded container having a screw fastening structure as described in any one of (1) to (4), characterized in that the first member and the second member are, respectively, either a container or a lid that can be attached to or detached from each other. (7) A rod-shaped member having a screw fastening structure as described in any one of (1) to (4), characterized in that the first member and the second member are each either one or the other of a first rod-shaped member and a second rod-shaped member that are detachable from each other.

[0047] (8) A screw fastening structure connecting a first member having a male threaded portion at one end, a second member having a female threaded portion at one end, and / or a third member having a male threaded portion or a female threaded portion at one end and the other end, The male thread portion of the first member is configured such that at least one thread of a male screw having a length of 1 / (2n) of the circumference, with n threads (n: a natural number) per circumference, is arranged at equal intervals in the circumferential direction, or at least one thread of a male screw having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction. The female thread portion of the second member is configured such that at least one thread of a female screw having a length of 1 / (2n) of the circumference is arranged at equal intervals in the circumferential direction, or at least one thread of a female screw having a length of 1 / (2n) or less of the circumference is arranged at equal intervals in the circumferential direction, The male thread portion of the third member is configured such that at least one thread of the male thread, each having a length of 1 / (2n) of the circumference, is arranged at equal intervals in the circumferential direction, or at least one thread of the male thread, each having a length of 1 / (2n) or less of the circumference, is arranged at equal intervals in the circumferential direction. The female thread portion of the third member is configured such that at least one thread of the female thread, each having a length of 1 / (2n) of the circumference, is arranged at equal intervals in the circumferential direction, or at least one thread of the female thread, each having a length of 1 / (2n) or less of the circumference, is arranged at equal intervals in the circumferential direction. The male thread portion, having at least one thread of the male thread having a length of 1 / (2n) of the circumference and n threads per circumference, is arranged at equal intervals in the circumferential direction, and the female thread portion, having at least one thread of the female thread having a length of 1 / (2n) or less of the circumference, is fastened together. and / or, The male thread portion, in which at least one thread of the male thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, is fastened to the female thread portion, in which at least one thread of the female thread, each having a length of 1 / (2n) per circumference, is arranged at equal intervals in the circumferential direction. A screw-tightening structure characterized by the following: (9) The male thread portion, in which at least one thread of the male thread having a length of 1 / (2n) of the circumference per circumference is arranged at equal intervals in the circumferential direction, and the female thread portion, in which at least one thread of the female thread having a length of 1 / (2n) of the circumference per circumference is arranged at equal intervals in the circumferential direction, each has a first slider portion formed in a curved shape at the tip side surface of first thread of the male thread and the tip side surface of the tip side surface of the tip side surface of the rotational direction when fastened, which curves away from the tip side surface as you go from the downstream side to the upstream side in the rotational direction, and / or, The female thread portion, in which at least one thread of the female thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, and the male thread portion, in which at least one thread of the male thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, is connected to the tip surface of the first thread of the female thread and the first thread of the male thread at the leading edge, respectively, and the tip surface is formed in a curved shape that curves away from the leading edge as it moves from the downstream side to the upstream side in the rotational direction during fastening. The screw fastening structure described in (8) above, characterized in that (10) In the male threaded portion, at least one thread of the male thread having a length of 1 / (2n) of the circumference around one circumference is arranged at equal intervals in the circumferential direction, and in the female threaded portion, at least one thread of the female thread having a length of 1 / (2n) of the circumference around one circumference is arranged at equal intervals in the circumferential direction, a first occlusal portion is formed at the upstream end of at least one thread of the male thread and one thread of the female thread at the rearmost end in the direction of rotation when fastened, extending in the direction of rotation axis of the male thread and the female thread, and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. In the female thread portion, at least one thread of the female thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, and in the male thread portion, at least one thread of the male thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, a second occlusal portion is formed at the downstream end of at least one thread of the female thread and one thread of the male thread, each extending in the direction of the rotation axis of the female thread and the male thread, and having a wedge shape when viewed in cross-section in the direction of the rotation axis. The screw fastening structure according to (8) or (9), characterized in that the first occlusal portion and the second occlusal portion occlude with each other when the male screw portion and the female screw portion are fastened together. (11) A first rib is formed on the outer surface on which the male screw is formed, extending in the direction of the rotation axis of the male screw. A second rib is formed on the inner circumferential surface where the female thread is formed, extending in the direction of the rotation axis of the female thread. A screw fastening structure according to any one of (8) to (10), characterized in that when the male screw portion and the female screw portion are fastened together, the first rib and the second rib overcome each other and engage. (12) A writing instrument having a screw-fastening structure as described in any one of (8) to (11), characterized in that the first member, the second member, and the third member are each one of three or more detachable cylindrical cases for a writing instrument. (13) A rod-shaped member having a screw fastening structure as described in any one of (8) to (11), characterized in that the first member, the second member, and the third member are each one of a first rod-shaped member, a second rod-shaped member, and a third rod-shaped member that are detachable from each other.

[0048] (14) A screw fastening structure that connects a first member having a male threaded portion at one end and a second member having a female threaded portion at one end, The male thread portion of the first member has at least one thread of male screws, each having a length of 1 / (2n+1) or less and n+1 (n: a natural number) per circumference, arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of female screws, each having a length of n / ((2n+1)(n+1)) per circumference, arranged at equal intervals in the circumferential direction, Or, The male thread portion of the first member has at least one thread of n+1 male threads with a length of n / ((2n+1)(n+1)) circumferences arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of n+1 female threads with a length of 1 / (2n+1) circumference or less arranged at equal intervals in the circumferential direction. A screw-tightening structure characterized by the following: (15) The male thread portion, in which at least one thread of the male thread having a length of 1 / (2n+1) or less and n+1 threads per circumference is arranged at equal intervals in the circumferential direction, and the female thread portion, in which at least one thread of the female thread having a length of 1 / (2n+1) or less and n+1 threads per circumference is arranged at equal intervals in the circumferential direction, each has a first slider portion formed in a curved shape at the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the rotational direction when fastened, which curves away from the tip side surface as you go from the downstream side to the upstream side in the rotational direction. and / or, The female thread portion, having n+1 female threads with a length of n / ((2n+1)(n+1)) circumferences per turn, is arranged at equal intervals in the circumferential direction, and the male thread portion, having n+1 male threads with a length of n / ((2n+1)(n+1)) circumferences per turn, is arranged at equal intervals in the circumferential direction, respectively, has a second slider portion formed by connecting the tip side surface of the tip of the first female thread and the tip of the first male thread at the leading edge, respectively, the tip side surface being formed in a curved shape that curves away from the leading edge as you move from the downstream side to the upstream side in the rotational direction during fastening. The screw fastening structure described in (14) above, characterized in that (16) In the male threaded portion, at least one thread of the male thread having a length of 1 / (2n+1) or less and n+1 threads per circumference is arranged at equal intervals in the circumferential direction, and in the female threaded portion, at least one thread of the female thread having a length of 1 / (2n+1) or less and n+1 threads per circumference is arranged at equal intervals in the circumferential direction, a first occlusal portion is formed at the upstream end of at least one thread of the male thread and one thread of the female thread at the rearmost end in the direction of rotation when fastened, extending in the direction of rotation axis of the male thread and the female thread, and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. In the female thread portion, at least one thread of the female thread having a length of n / ((2n+1)(n+1)) circumferences per circumference is arranged at equal intervals in the circumferential direction, and in the male thread portion, at least one thread of the male thread having a length of n / ((2n+1)(n+1)) circumferences per circumference is arranged at equal intervals in the circumferential direction, a second occlusal portion is formed at the downstream end in the rotational direction when fastening, at least one thread of the female thread and one thread of the male thread at the outermost end, extending in the rotational direction of the female thread and the male thread, respectively, and having a wedge shape when viewed in cross-section in the rotational direction. The screw fastening structure according to (14) or (15), characterized in that the first occlusal portion and the second occlusal portion occlude with each other when the male screw portion and the female screw portion are fastened together. (17) A first rib is formed on the outer circumferential surface on which the male thread is formed, extending in the direction of the rotation axis of the male thread. A second rib is formed on the inner circumferential surface where the female thread is formed, extending in the direction of the rotation axis of the female thread. A screw fastening structure according to any one of (14) to (16), characterized in that when the male screw portion and the female screw portion are fastened together, the first rib and the second rib overcome each other and engage. (18) A writing instrument having a screw-fastening structure as described in any one of (14) to (17), characterized in that the first member and the second member are one and the other of two detachable cylindrical cases of a writing instrument, respectively. (19) A lidded container having a screw fastening structure as described in any one of (14) to (17), characterized in that the first member and the second member are, respectively, either one or the other of a container and a lid that are detachable from each other. (20) A rod-shaped member having a screw fastening structure as described in any one of (14) to (17), characterized in that the first member and the second member are each either one or the other of a first rod-shaped member and a second rod-shaped member that are detachable from each other.

[0049] (21) A screw fastening structure connecting a first member having a male threaded portion at one end, a second member having a female threaded portion at one end, and / or a third member having a male threaded portion or a female threaded portion at one end and the other end, The male thread portion of the first member is arranged in such a way that at least one thread of a male screw having a length of 1 / (2n+1) turns or less, with n+1 threads (n: natural number) per turn, is arranged at equal intervals in the circumferential direction, or at least one thread of a male screw having a length of n / ((2n+1)(n+1)) turns, with n+1 threads per turn, is arranged at equal intervals in the circumferential direction. The female thread portion of the second member is configured such that at least one female thread, each having a length of 1 / (2n+1) or less and n+1 threads per circumference, is arranged at equal intervals in the circumferential direction, or at least one female thread, each having a length of n / ((2n+1)(n+1)) threads per circumference, is arranged at equal intervals in the circumferential direction. The male thread portion of the third member is configured such that at least one thread of the male thread, having a length of 1 / (2n+1) or less and n+1 threads per circumference, is arranged at equal intervals in the circumferential direction, or at least one thread of the male thread, having a length of n / ((2n+1)(n+1)) threads per circumference, is arranged at equal intervals in the circumferential direction. The female thread portion of the third member is such that at least one thread of the female thread, each having a length of 1 / (2n+1) or less and n+1 threads per circumference, is arranged at equal intervals in the circumferential direction, or at least one thread of the female thread, each having a length of n / ((2n+1)(n+1)) threads per circumference, is arranged at equal intervals in the circumferential direction. The male threaded portion, in which at least one thread of the male thread, each having a length of 1 / (2n+1) or less and n+1 threads per circumference, is arranged at equal intervals in the circumferential direction, is fastened to the female threaded portion, in which at least one thread of the female thread, each having a length of n / ((2n+1)(n+1)) threads per circumference, is arranged at equal intervals in the circumferential direction. and / or, The male thread portion, having n+1 male threads with a length of n / ((2n+1)(n+1)) circumferences per turn, arranged at equal intervals in the circumferential direction, is fastened to the female thread portion, having n+1 female threads with a length of 1 / (2n+1) circumference or less per turn, arranged at equal intervals in the circumferential direction. A screw-tightening structure characterized by the following: (22) The male thread portion, in which at least one thread of the male thread having a length of 1 / (2n+1) or less and n+1 threads per circumference is arranged at equal intervals in the circumferential direction, and the female thread portion, in which at least one thread of the female thread having a length of 1 / (2n+1) or less and n+1 threads per circumference is arranged at equal intervals in the circumferential direction, each has a first slider portion formed in a curved shape at the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the tip side surface of the rotational direction when fastened, which curves away from the tip side surface as you go from the downstream side to the upstream side in the rotational direction. and / or, The female thread portion, having n+1 female threads with a length of n / ((2n+1)(n+1)) circumferences per turn, is arranged at equal intervals in the circumferential direction, and the male thread portion, having n+1 male threads with a length of n / ((2n+1)(n+1)) circumferences per turn, is arranged at equal intervals in the circumferential direction, respectively, has a second slider portion formed by connecting the tip side surface of the tip of the first female thread and the tip of the first male thread at the leading edge, respectively, the tip side surface being formed in a curved shape that curves away from the leading edge as you move from the downstream side to the upstream side in the rotational direction during fastening. The screw fastening structure described in (21) above, characterized in that (23) In the male threaded portion, at least one thread of the male thread having a length of 1 / (2n+1) or less and n+1 threads per circumference is arranged at equal intervals in the circumferential direction, and in the female threaded portion, at least one thread of the female thread having a length of 1 / (2n+1) or less and n+1 threads per circumference is arranged at equal intervals in the circumferential direction, a first occlusal portion is formed at the upstream end of at least one thread of the male thread and one thread of the female thread at the rearmost end in the direction of rotation when fastened, extending in the direction of rotation axis of the male thread and the female thread, and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. In the female thread portion, at least one thread of the female thread having a length of n / ((2n+1)(n+1)) circumferences per circumference is arranged at equal intervals in the circumferential direction, and in the male thread portion, at least one thread of the male thread having a length of n / ((2n+1)(n+1)) circumferences per circumference is arranged at equal intervals in the circumferential direction, a second occlusal portion is formed at the downstream end in the rotational direction when fastening, at least one thread of the female thread and one thread of the male thread at the outermost end, extending in the rotational direction of the female thread and the male thread, respectively, and having a wedge shape when viewed in cross-section in the rotational direction. The screw fastening structure according to (21) or (22), characterized in that the first occlusal portion and the second occlusal portion occlude with each other when the male screw portion and the female screw portion are fastened together. (24) A first rib is formed on the outer surface on which the male screw is formed, extending in the direction of the rotation axis of the male screw. A second rib is formed on the inner circumferential surface where the female thread is formed, extending in the direction of the rotation axis of the female thread. A screw fastening structure according to any one of (21) to (23), characterized in that when the male screw portion and the female screw portion are fastened together, the first rib and the second rib overcome each other and engage. (25) A writing instrument having a screw-fastening structure as described in any one of (21) to (24), characterized in that the first member, the second member, and the third member are each one of three or more detachable cylindrical cases for a writing instrument. (26) A rod-shaped member having a screw fastening structure as described in any one of (21) to (24), characterized in that the first member, the second member, and the third member are each one of a first rod-shaped member, a second rod-shaped member, and a third rod-shaped member that are detachable from each other. [Explanation of symbols]

[0050] 1 ballpoint pen 2. Cylindrical case 21 Front cylindrical case 211 Protrusion 212 Stepped section 22 Rear cylindrical case 3 Male threaded section 31 Male screw 311 Male threaded pair 3111 Threaded groove on the tip side in the insertion direction 3112 Threaded groove on the rear end in the insertion direction 312 Cavity 32. First slider section 321 Curved surface 33 First occlusal part 331 First occlusal process 34. First Rib 4 Female threaded section 41 Female thread 411 Female threaded pair 4111 Threaded groove on the tip side in the insertion direction 4112 Threaded groove on the rear end in the insertion direction 412 Cavity 42 Second slider section 421 Curved surface 43 Second occlusal part 431 Second occlusal process 44. Second Rib 5. One part of the disassembled handle.

Claims

1. In a screw fastening structure that connects a first member having a male threaded portion at one end and a second member having a female threaded portion at one end, The male thread portion of the first member has at least one thread of a male screw having a length of 1 / (2n) of the circumference, arranged at equal intervals in the circumferential direction, with n threads (n: a natural number) per circumference, and the female thread portion of the second member has at least one thread of a female screw having a length of 1 / (2n) or less per circumference, arranged at equal intervals in the circumferential direction, A first slider portion is formed in conjunction with the tip side surface of the tip side surface of the tip of the tip of the male screw portion at the leading edge, which has a curved shape that curves away from the leading edge as it moves from the downstream side to the upstream side in the rotational direction when fastening, and / or a second slider portion is formed in conjunction with the tip side surface of the tip of the tip of the female screw portion at the leading edge, which has a curved shape that curves away from the leading edge as it moves from the downstream side to the upstream side in the rotational direction when fastening, Or, The male thread portion of the first member has at least one thread of n male threads, each having a length of 1 / (2n) or less, arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of n female threads, each having a length of 1 / (2n) in the circumferential direction, arranged at equal intervals in the circumferential direction. A first slider portion is formed in conjunction with the tip side surface of the tip side surface of the tip of the tip of the female screw portion at the leading edge, which has a curved shape that curves away from the leading edge as it moves from the downstream to the upstream side in the rotational direction when fastening, and / or a second slider portion is formed in conjunction with the tip side surface of the tip of the tip of the male screw portion at the leading edge, which has a curved shape that curves away from the leading edge as it moves from the downstream to the upstream side in the rotational direction when fastening, as it moves from the downstream to the upstream side in the rotational direction when fastening, as it moves from the leading edge A screw-tightening structure characterized by the following:

2. A first rib is formed on the outer circumferential surface on which the male screw is formed, extending in the direction of the rotation axis of the male screw. A second rib is formed on the inner circumferential surface where the female thread is formed, extending in the direction of the rotation axis of the female thread. The screw fastening structure according to claim 1, characterized in that the first rib and the second rib overcome each other and engage when the male screw portion and the female screw portion are fastened together.

3. A screw fastening structure connecting a first member having a male threaded portion at one end and a second member having a female threaded portion at one end, The male thread portion of the first member has at least one thread of a male screw having a length of 1 / (2n) of the circumference, arranged at equal intervals in the circumferential direction, with n threads (n: a natural number) per circumference, and the female thread portion of the second member has at least one thread of a female screw having a length of 1 / (2n) or less per circumference, arranged at equal intervals in the circumferential direction, A first occlusal portion is formed at the upstream end of at least one thread of the male screw, which has a length of 1 / (2n) of one circumference per circumference, in the male screw portion, where at least one thread of the male screw at the rearmost end is arranged at equal intervals in the circumferential direction, and the first occlusal portion extends in the direction of rotation of the male screw and protrudes downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation is wedge-shaped. A second occlusal portion is formed at the downstream end of at least one thread of the female screw, which has a length of 1 / (2n) of one circumference or less per circumference, in the female screw portion, where at least one thread of the female screw, which has a length of 1 / (2n) of one circumference or less per circumference, is arranged at equal intervals in the circumferential direction, in the downstream end of at least one thread of the female screw, which has a length of 1 / (2n) of one circumference or less, in the direction of rotation when fastened, and the second occlusal portion extends in the direction of rotation of the female screw and protrudes downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation is wedge-shaped. Or, The male thread portion of the first member has at least one thread of n male threads, each having a length of 1 / (2n) or less, arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of n female threads, each having a length of 1 / (2n) in the circumferential direction, arranged at equal intervals in the circumferential direction. In the female thread portion, at least one thread of the female thread, each having a length of 1 / (2n) of the circumference and n threads per circumference, is arranged at equal intervals in the circumferential direction. A first occlusal portion is formed at the upstream end of at least one thread of the female thread at the rearmost end, extending in the direction of rotation of the female thread and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation is wedge-shaped. In the male thread portion, at least one thread of the male thread, each having a length of 1 / (2n) of the circumference or less and n threads per circumference, is arranged at equal intervals in the circumferential direction. A second occlusal portion is formed at the downstream end of at least one thread of the male thread at the furthest end, extending in the direction of rotation of the male thread and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation is wedge-shaped. When the male screw portion and the female screw portion are fastened together, the first occlusal portion and the second occlusal portion occlude with each other. A screw-tightening structure characterized by the following:

4. A first rib is formed on the outer circumferential surface on which the male screw is formed, extending in the direction of the rotation axis of the male screw. A second rib is formed on the inner circumferential surface where the female thread is formed, extending in the direction of the rotation axis of the female thread. The screw fastening structure according to claim 3, characterized in that the first rib and the second rib overcome each other and engage when the male screw portion and the female screw portion are fastened together.

5. A writing instrument having a screw-fastening structure according to any one of claims 1 to 4, characterized in that the first member and the second member are, respectively, one and the other of two detachable cylindrical cases of a writing instrument.

6. A lidded container having a screw-fastening structure according to any one of claims 1 to 4, characterized in that the first member and the second member are, respectively, either one or the other of a container and a lid that are detachable from each other.

7. A rod-shaped member having a screw fastening structure according to any one of claims 1 to 4, characterized in that the first member and the second member are, respectively, either one or the other of a first rod-shaped member and a second rod-shaped member that are detachable from each other.

8. In a screw fastening structure connecting a first member having a male threaded portion at one end, a second member having a female threaded portion at one end, and / or a third member having a male threaded portion or a female threaded portion at one end and the other end, The male thread portion of the first member is configured such that at least one thread of a male screw having a length of 1 / (2n) of the circumference, with n threads (n: a natural number) per circumference, is arranged at equal intervals in the circumferential direction, or at least one thread of a male screw having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction. The female thread portion of the second member is configured such that at least one thread of a female screw having a length of 1 / (2n) of the circumference is arranged at equal intervals in the circumferential direction, or at least one thread of a female screw having a length of 1 / (2n) or less of the circumference is arranged at equal intervals in the circumferential direction. The male thread portion of the third member is configured such that at least one thread of the male thread, each having a length of 1 / (2n) of the circumference, is arranged at equal intervals in the circumferential direction, or at least one thread of the male thread, each having a length of 1 / (2n) or less of the circumference, is arranged at equal intervals in the circumferential direction. The female thread portion of the third member is configured such that at least one thread of the female thread, each having a length of 1 / (2n) of the circumference, is arranged at equal intervals in the circumferential direction, or at least one thread of the female thread, each having a length of 1 / (2n) or less of the circumference, is arranged at equal intervals in the circumferential direction. The male thread portion, having at least one thread of the male thread having a length of 1 / (2n) of the circumference and n threads per circumference (n: a natural number), is arranged at equal intervals in the circumferential direction, and the female thread portion, having at least one thread of the female thread having a length of 1 / (2n) or less of the circumference and n threads per circumference, is fastened together with the female thread portion, and / or, The male thread portion, in which at least one thread of the male thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, is fastened to the female thread portion, in which at least one thread of the female thread, each having a length of 1 / (2n) per circumference, is arranged at equal intervals in the circumferential direction. A screw-tightening structure characterized by the following:

9. A first slider portion is formed in conjunction with the tip side surface of the tip side surface of the tip of the tip of the male screw portion at the leading edge, which has a curved shape that curves away from the leading edge as it moves from the downstream side to the upstream side in the rotational direction when fastening, and / or a second slider portion is formed in conjunction with the tip side surface of the tip of the tip of the female screw portion at the leading edge, which has a curved shape that curves away from the leading edge as it moves from the downstream side to the upstream side in the rotational direction when fastening, Or, A first slider portion is formed in conjunction with the tip side surface of the tip side surface of the tip of the tip of the female screw portion at the leading edge, which has a curved shape that curves away from the leading edge as it moves from the downstream to the upstream side in the rotational direction when fastening, and / or a second slider portion is formed in conjunction with the tip side surface of the tip of the tip of the male screw portion at the leading edge, which has a curved shape that curves away from the leading edge as it moves from the downstream to the upstream side in the rotational direction when fastening, as it moves from the downstream to the upstream side in the rotational direction when fastening, as it moves from the leading edge The screw fastening structure according to feature 8.

10. In the male threaded portion, at least one thread of the male thread having a length of 1 / (2n) of one circumference is arranged at equal intervals in the circumferential direction, and in the female threaded portion, at least one thread of the female thread having a length of 1 / (2n) of one circumference is arranged at equal intervals in the circumferential direction, a first occlusal portion is formed at the upstream end of at least one thread of the male thread and one thread of the female thread at the rearmost end, in the direction of rotation when fastened, extending in the direction of rotation axis of the male thread and the female thread, and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. In the female thread portion, at least one thread of the female thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, and in the male thread portion, at least one thread of the male thread, each having a length of 1 / (2n) or less per circumference, is arranged at equal intervals in the circumferential direction, a second occlusal portion is formed at the downstream end of at least one thread of the female thread and one thread of the male thread, each extending in the direction of rotation axis of the female thread and the male thread, and projecting downstream in the direction of rotation axis, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. The screw fastening structure according to claim 8, characterized in that the first occlusal portion and the second occlusal portion occlude with each other when the male screw portion and the female screw portion are fastened together.

11. A first rib is formed on the outer circumferential surface on which the male screw is formed, extending in the direction of the rotation axis of the male screw. A second rib is formed on the inner circumferential surface where the female thread is formed, extending in the direction of the rotation axis of the female thread. The screw fastening structure according to claim 8, characterized in that the first rib and the second rib overcome each other and engage when the male screw portion and the female screw portion are fastened together.

12. A writing instrument having a screw-fastening structure according to any one of claims 8 to 11, characterized in that the first member, the second member, and the third member are each one of three or more detachable cylindrical cases for a writing instrument.

13. A rod-shaped member having a screw-fastening structure according to any one of claims 8 to 11, characterized in that the first member, the second member, and the third member are each one of a first rod-shaped member, a second rod-shaped member, and a third rod-shaped member that are detachable from each other.

14. In a screw fastening structure that connects a first member having a male threaded portion at one end and a second member having a female threaded portion at one end, The male thread portion of the first member has at least one thread of male screws, each having a length of 1 / (2n+1) or less and n+1 (n: a natural number) per circumference, arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of female screws, each having a length of n / ((2n+1)(n+1)) per circumference, arranged at equal intervals in the circumferential direction, A first slider portion is formed in conjunction with the tip side surface of Or, The male thread portion of the first member has at least one thread of n+1 male threads, each having a length of n / ((2n+1)(n+1)) circumferences, arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of n+1 female threads, each having a length of 1 / (2n+1) circumferences or less, arranged at equal intervals in the circumferential direction. A first slider portion is formed in conjunction with the tip side surface of A screw-tightening structure characterized by the following:

15. A first rib is formed on the outer circumferential surface on which the male screw is formed, extending in the direction of the rotation axis of the male screw. A second rib is formed on the inner circumferential surface where the female thread is formed, extending in the direction of the rotation axis of the female thread. The screw fastening structure according to claim 14, characterized in that the first rib and the second rib overcome each other and engage when the male screw portion and the female screw portion are fastened together.

16. A screw fastening structure connecting a first member having a male threaded portion at one end and a second member having a female threaded portion at one end, The male thread portion of the first member has at least one thread of male screws, each having a length of 1 / (2n+1) or less and n+1 (n: a natural number) per circumference, arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of female screws, each having a length of n / ((2n+1)(n+1)) per circumference, arranged at equal intervals in the circumferential direction, A first occlusal portion is formed at the upstream end of at least one thread of the male screw at the rearmost end, in which at least one thread of the male screw has a length of 1 / (2n+1) or less per circumference and is arranged at equal intervals in the circumferential direction, extending in the direction of rotation axis of the male screw and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. A second occlusal portion is formed at the downstream end of at least one thread of the female screw at the frontmost end, in which at least one thread of the female screw has a length of n / ((2n+1)(n+1)) per circumference and is arranged at equal intervals in the circumferential direction, extending in the direction of rotation axis of the female screw and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. Or, The male thread portion of the first member has at least one thread of n+1 male threads, each having a length of n / ((2n+1)(n+1)) circumferences, arranged at equal intervals in the circumferential direction, and the female thread portion of the second member has at least one thread of n+1 female threads, each having a length of 1 / (2n+1) circumferences or less, arranged at equal intervals in the circumferential direction. A first occlusal portion is formed at the upstream end of at least one female thread on the rearmost side of the female thread, in which at least one female thread has a length of 1 / (2n+1) circumference or less per circumference and is arranged at equal intervals in the circumferential direction, extending in the direction of rotation axis of the female thread and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. A second occlusal portion is formed at the downstream end of at least one male thread on the frontmost side of the male thread, in which at least one male thread has a length of n / ((2n+1)(n+1)) circumference per circumference and is arranged at equal intervals in the circumferential direction, extending in the direction of rotation axis of the male thread and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. A screw fastening structure characterized in that the first occlusal portion and the second occlusal portion occlude with each other when the male screw portion and the female screw portion are fastened together.

17. A first rib is formed on the outer circumferential surface on which the male screw is formed, extending in the direction of the rotation axis of the male screw. A second rib is formed on the inner circumferential surface where the female thread is formed, extending in the direction of the rotation axis of the female thread. The screw fastening structure according to claim 16, characterized in that the first rib and the second rib overcome each other and engage when the male screw portion and the female screw portion are fastened together.

18. A writing instrument having a screw-fastening structure according to any one of claims 14 to 17, characterized in that the first member and the second member are, respectively, one and the other of two detachable cylindrical cases of a writing instrument.

19. A lidded container having a screw-fastening structure as described in any one of claims 14 to 17, characterized in that the first member and the second member are, respectively, either one or the other of a container and a lid that are detachable from each other.

20. A rod-shaped member having a screw-fastening structure according to any one of claims 14 to 17, characterized in that the first member and the second member are, respectively, either one or the other of a first rod-shaped member and a second rod-shaped member that are detachable from each other.

21. In a screw fastening structure connecting a first member having a male threaded portion at one end, a second member having a female threaded portion at one end, and / or a third member having a male threaded portion or a female threaded portion at one end and the other end, The male thread portion of the first member is arranged in such a way that at least one thread of a male screw having a length of 1 / (2n+1) turns or less, with n+1 threads (n: natural number) per turn, is arranged at equal intervals in the circumferential direction, or at least one thread of a male screw having a length of n / ((2n+1)(n+1)) turns, with n+1 threads per turn, is arranged at equal intervals in the circumferential direction. The female thread portion of the second member is configured such that at least one female thread, each having a length of 1 / (2n+1) or less and n+1 threads per circumference, is arranged at equal intervals in the circumferential direction, or at least one female thread, each having a length of n / ((2n+1)(n+1)) threads per circumference, is arranged at equal intervals in the circumferential direction. The male thread portion of the third member is configured such that at least one thread of the male thread, having a length of 1 / (2n+1) or less and n+1 threads per circumference, is arranged at equal intervals in the circumferential direction, or at least one thread of the male thread, having a length of n / ((2n+1)(n+1)) threads per circumference, is arranged at equal intervals in the circumferential direction. The female thread portion of the third member is such that at least one thread of the female thread, each having a length of 1 / (2n+1) or less and n+1 threads per circumference, is arranged at equal intervals in the circumferential direction, or at least one thread of the female thread, each having a length of n / ((2n+1)(n+1)) threads per circumference, is arranged at equal intervals in the circumferential direction. The male threaded portion, in which at least one thread of the male thread having a length of 1 / (2n+1) or less and n+1 threads per circumference is arranged at equal intervals in the circumferential direction, is fastened to the female threaded portion, in which at least one thread of the female thread having a length of n / ((2n+1)(n+1)) threads per circumference is arranged at equal intervals in the circumferential direction, and / or, The male thread portion, having n+1 male threads with a length of n / ((2n+1)(n+1)) circumferences per turn, is fastened to the female thread portion, having n+1 female threads with a length of 1 / (2n+1) circumference or less per turn, is fastened to the female thread portion, having n+1 female threads with a length of 1 / (2n+1) circumference or less, is fastened to the female thread portion, which is fastened to the male thread portion, having n+1 female threads with a length of 1 / (2n+1) circumference or less, is fastened to the female thread portion, which male thread portion, having n+1 female threads with a length of 1 / (2n+1) circumference or less, is fastened to the female thread portion, which is fast A screw-tightening structure characterized by the following:

22. A first slider portion is formed in conjunction with the tip side surface of Or, A first slider portion is formed in conjunction with the tip side surface of The screw fastening structure according to feature 21.

23. In the male threaded portion, at least one thread of the male thread, each having a length of 1 / (2n+1) or less and n+1 threads per circumference, is arranged at equal intervals in the circumferential direction, and in the female threaded portion, at least one thread of the female thread, each having a length of 1 / (2n+1) or less and n+1 threads per circumference, is arranged at equal intervals in the circumferential direction, a first occlusal portion is formed at the upstream end of at least one thread of the male thread and one thread of the female thread at the rearmost end, in the direction of rotation when fastened, extending in the direction of rotation axis of the male thread and the female thread, and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. In the female thread portion, at least one thread of the female thread having a length of n / ((2n+1)(n+1)) circumferences per circumference is arranged at equal intervals in the circumferential direction, and in the male thread portion, at least one thread of the male thread having a length of n / ((2n+1)(n+1)) circumferences per circumference is arranged at equal intervals in the circumferential direction, a second occlusal portion is formed at the downstream end of at least one thread of the female thread and one thread of the male thread at the leading edge, in the direction of rotation when fastened, extending in the direction of rotation axis of the female thread and the male thread, and projecting downstream in the direction of rotation when fastened, such that the cross-sectional view in the direction of rotation axis is wedge-shaped. The screw fastening structure according to claim 21, characterized in that the first occlusal portion and the second occlusal portion occlude with each other when the male screw portion and the female screw portion are fastened together.

24. A first rib is formed on the outer circumferential surface on which the male screw is formed, extending in the direction of the rotation axis of the male screw. A second rib is formed on the inner circumferential surface where the female thread is formed, extending in the direction of the rotation axis of the female thread. The screw fastening structure according to claim 21, characterized in that when the male screw portion and the female screw portion are fastened together, the first rib and the second rib overcome each other and engage.

25. A writing instrument having a screw-fastening structure according to any one of claims 21 to 24, characterized in that the first member, the second member, and the third member are each one of three or more detachable cylindrical cases for a writing instrument.

26. A rod-shaped member having a screw-fastening structure as described in any one of claims 21 to 24, characterized in that the first member, the second member, and the third member are each one of a first rod-shaped member, a second rod-shaped member, and a third rod-shaped member that are detachable from each other.

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